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Linköping University
Department of Management and Engineering
Master Thesis, TQMT30 2021, Mechanical Engineering
Autumn 2021, LIU-IEI-TEK-A--21/04227—SE
A Comparison Study for Robot Planning
Automation Between CATIA V5 and
3D Experience
MASTER THESIS
Author’s: Vinayak Ramachandra Acharya(vinac187)
Veera Venkata Manikanta Virupaksh Raja Chowdary Rimmalapudi(veeri248)
Supervisor: Mehdi Tarkian
Industrial Supervisor: Henrik Kihlman
Examiner: Johan Persson
Linköping University
SE – 58183 Linköping, Sweden
+46013281000, www.liu.se
Authors
Veera Venkata Manikanta Virupaksha Raja Chowdary Rimmalapudi
M.Sc. Mechanical Engineering
Linköping University, Sweden
Vinayak Ramachandra Acharya
M.Sc. Mechanical Engineering
Linköping University, Sweden
Supervisor
Mehdi Tarkian
IEI, Division of Machine Design
Linköping University, Sweden
Industrial Supervisor
Henrik Kihlman
Customer Solutions Architect
Prodtex, Göteborg, Sweden
Examiner
Johan Persson
IEI, Division of Machine Design
Linköping University, Sweden
i
Abstract
As the world is evolving very fast with the developments of new technologies and softwares in
design and manufacturing, business organizations and manufacturing industries will always be
adapting to the new technologies and softwares for increasing the cost and time efficiency in the
development of products. So, this thesis focuses on a comparative study between two Dassault
Systems softwares in which, one is mostly used CAD software by industries for a long time, and
one is the latest developments in the CAD softwares with satisfying business requirements.
For this comparison study, the two methods called design automation and robot simulation are
used in the development of modular fixtures platforms used in automobile manufacturing
industries. In the first method, the design and assembly of modular fixtures platform are done
which holds the automotive car sheet pillars together. By single mouse click, the complete design
and assembly of the modular fixtures can be done using automation. In the second method, the
spot-welding manufacturing operation is done to join the car sheet pillars together to produce the
B-pillar of the Body in white (BIW) for the automobile, with the help of a welding gun connected
to ABB robot arm, using automation in robot simulation.
This work takes place in CATIA V5 and 3D Experience, and the final results obtained in both the
software are compared and discussed in the results part of this report. Automation in CAD has
been one of the advanced developments that happened in the 21st century through which most of
the engineering knowledge and intent can be captured and reutilized. Automation in CATIA V5
& 3D Experience is done using two programming languages called VB (Visual Basics) and
VB.net.
ii
Acknowledgement
We would like to thank our supervisor Prof. Mehdi Tarkian, for giving wonderful opportunity
and support to work on this master thesis at Linköping University. We appreciate his patience,
guidance, opinions, advice, and constructive criticism for our shortcomings.
We would like to thank our industry supervisor Dr Henrik Kihlman, for his encouragement,
assistance, quick replies to the queries in need over the last six months.
We are extremely grateful for their cooperation, wisdom, and knowledge in solving any problems
that arose during our project.
We would like to thank Anton Wiberg, for providing his valuable time and responding quickly to
help us in solving the technical issues of the software.
We would like to acknowledge our examiner Johan Persson for his assistance in evaluating our
work and providing suggestions throughout the thesis time.
We would like to thank our colleagues Albin Parappilly Albert and Sanjay Nambiar for joining
us on this journey for the past few months.
Finally, we would like to express our gratitude to our family for providing unconditional support
and encouragement for every step we take throughout our journey in the master’s program at
Linköping University.
Expressing our heartful thanks to your presence in our life and this journey, without you this
journey is incomplete.
Raja Chowdary & Vinayak Acharya
Linköping, September 2021
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Table of Contents Abstract .......................................................................................................................................................... i
Acknowledgement ........................................................................................................................................ ii
List of Figure................................................................................................................................................. v
Abbreviation: .............................................................................................................................................. vii
1. Introduction ........................................................................................................................................... 1
1.1. Background ................................................................................................................................... 1
1.2. Problem Statement ........................................................................................................................ 2
1.3. Literature Review .......................................................................................................................... 2
1.4. Purpose .......................................................................................................................................... 3
1.4.1. Research Questions ............................................................................................................... 3
1.4.2. Deliverables .......................................................................................................................... 3
1.5. Delimitations ................................................................................................................................. 4
1.6. Thesis Overview ........................................................................................................................... 4
2. Theory ................................................................................................................................................... 5
2.1. CAD .............................................................................................................................................. 5
2.2. Product Lifecycle Management (PLM) ........................................................................................ 6
2.3. Fixtures ......................................................................................................................................... 7
2.3.1. Fundamentals of Fixture Design ........................................................................................... 8
2.3.2. Modular Fixture .................................................................................................................... 9
2.3.3. Reconfigurable Fixtures ........................................................................................................ 9
2.3.4. Units of Modular Fixture Platform (MFP) .......................................................................... 10
2.3.5. Three-Two-One Method ..................................................................................................... 14
2.4. Digital Manufacturing ................................................................................................................. 15
2.5. Body in White (BIW) .................................................................................................................. 17
2.5.1. Car B-pillar ......................................................................................................................... 18
2.6. Knowledge-Based Engineering ................................................................................................... 19
3. Methodology ....................................................................................................................................... 20
3.1. Project workflow ......................................................................................................................... 20
3.2. Design Automation (DA) ............................................................................................................ 21
3.2.1. Modeling Apps .................................................................................................................... 24
3.3. Robot Simulation (RS) ................................................................................................................ 25
3.3.1. Modelling Apps................................................................................................................... 29
iv
3.4. VB (Visual Basics) and VB.net: ................................................................................................. 29
4. Results ................................................................................................................................................. 31
4.1. Comparison ................................................................................................................................. 31
4.2. Design Automation: .................................................................................................................... 31
4.2.1. Comparison between codes ................................................................................................. 34
4.3. Robot Simulation: ....................................................................................................................... 42
4.3.1. Comparison of codes ........................................................................................................... 43
5. Discussion ........................................................................................................................................... 50
5.1. Project Outcome .......................................................................................................................... 50
5.2. Answering The Research Question ............................................................................................. 51
6. Conclusion .......................................................................................................................................... 54
6.1. Future Work ................................................................................................................................ 54
References ................................................................................................................................................... 55
Appendix ..................................................................................................................................................... 59
Appendix 1: ................................................................................................................................................. 59
1.1 Catia V5 Design Automation Codes using Visual Basics .................................................................... 59
Generation of Modular Fixtures .......................................................................................................... 59
1.2 3D Experience Automation Codes using Visual Studio ....................................................................... 93
Generation of Modular Fixtures .......................................................................................................... 93
Appendix 2: ............................................................................................................................................... 124
2.1 CATIA V5 Robot Simulation Automation Codes using Visual Basics .............................................. 124
2.2 3D Experience Robot Simulation Automation Codes using VB.Net.................................................. 126
v
List of Figure Figure 1: Thesis overview ............................................................................................................... 4 Figure 2: Evolution of CAD ........................................................................................................... 5 Figure 3: Traditional Fixtures in Automobile Industries (Volkswagen, 2020) .............................. 8 Figure 4: Clamps Assembled to Holder ........................................................................................ 11 Figure 5: Locator........................................................................................................................... 11 Figure 6: (A)Clamp Support Figure 7: (B) Locator Support ...................................................... 12 Figure 8: Base Unit ....................................................................................................................... 13 Figure 9: Control Unit ................................................................................................................... 13 Figure 10: Twelve Degrees of Freedom ....................................................................................... 15 Figure 11: Domains of the digital manufacturing process ............................................................ 16 Figure 12: Body in White (Volvo, 2014) ...................................................................................... 18 Figure 13: Overall Project workflow ............................................................................................ 20 Figure 14: Flowchart for Design Automation ............................................................................... 22 Figure 15:Modular fixture Design using CATIA V5 ................................................................... 23 Figure 16: Production Planning Process ....................................................................................... 26 Figure 17: Flowchart for automatic robot simulation ................................................................... 27 Figure 18: Design of Production Planning.................................................................................... 28 Figure 19: Import definitions in VB.Net....................................................................................... 30 Figure 20: Tool Sweep in 3D Experience ..................................................................................... 31 Figure 21: User Interface of 3D Experience ................................................................................. 32 Figure 22: User Interface of CATIA V5 ....................................................................................... 32 Figure 23: 3D Experience Action Bar in Generative Shape Design ............................................. 33 Figure 24: CATIA V5 Action Bar in Generative Shape Design .................................................. 33 Figure 25: GetPart Function in Visual Studio for 3D Experience ................................................ 34 Figure 26: GetPart in Visual Basic for CATIA V5....................................................................... 35 Figure 27: Product Creation in Visual Studio for 3D Experience ................................................ 35 Figure 28: Product creation in Visual Basics for CATIA V5 ....................................................... 36 Figure 29: Copy & Paste in Visual Studio for 3D Experience ..................................................... 36 Figure 30: Copy & Paste in Visual Basics for CATIA V5 ........................................................... 36 Figure 31: Instantiation in CATIA V5 & 3D Experience using VB & VB.net ............................ 37 Figure 32: Axis Creation in Visual Studio for 3D Experience ..................................................... 38 Figure 33: Axis Transformation in Visual Studio for 3D Experience .......................................... 39 Figure 34: Axis Transformation in Visual Basics for CATIA V5 ................................................ 39
Figure 35: Design assembly of MFP in CATIA V5 ..................................................................... 40 Figure 36: Design assembly of MFP in 3D Experience ............................................................... 40 Figure 37: 3D Experience Action Bar in Robot Spot Simulation ................................................. 42 Figure 38: CATIA V5 Interface of Device Task Definition ......................................................... 43 Figure 39: Get Entity using VPMOccurence in Visual Studio for 3D Experience ...................... 44 Figure 40: Get Part in Visual Basics for CATIA V5 .................................................................... 44 Figure 41: Spot Weld Trajectory in Visual Studio for 3D Experience ......................................... 45 Figure 42: Tag Group in Visual Basics for CATIA V5 ................................................................ 46 Figure 43: Robot Task in Visual Studio for 3D Experience ......................................................... 46
vi
Figure 44: Robot Task in Visual Basics for CATIA V5 ............................................................... 47 Figure 45: Spot operations in Visual Studio for 3D Experience .................................................. 47 Figure 46: Robot motions & operations in Visual Basics for CATIA V5 .................................... 48 Figure 47: Play Simulation in Visual Studio for 3D Experience .................................................. 49 Figure 48: Play Simulation in Visual Basics for CATIA V5........................................................ 49
vii
Abbreviation:
AI - Artificial Intelligence
API - Application Programming Interface
BIW - Body in White
CAD -Computer Added Design
CAE - Computer Aided Engineering
CAM - Computer Aided Manufacturing Process
CADA - Computer Aided Design Automation
CADT – Computer Aided Drafting
CAFD - Computer Aided Fixture Design
CAFDA - Computer Aided Fixture Design Automation
CAFM - Computer Aided Fixture Manufacturing
CARS – Computer Aided Robot Simulation
CIM - Computer Integrated Manufacturing Environment
CATIA - Computer Aided Three-Dimensional Interactive Application
DA – Design Automation
DOF - Degrees of Freedom
DTD – Device Task Definition
FMS - Flexible Manufacturing Systems
GSD - Generative Shape Design
KBE - Knowledge Based Engineering
KBS - Knowledge Based System
MF - Modular Fixtures
MFP - Modular Fixtures Platform
PD - Part Design
PLM - Product Lifecycle Management
PPR - Product, Process & Resources
PSI – Panel Side Inner
viii
PSO – Panel Side Outer
RMP - Robot Manufacturing Process
RSM - Responsive Manufacturing System
RSA – Robot Simulation Automation
RSO – Robot Spot-welding Operation
RS – Robot Simulation
RSS – Robot Spot Simulation
SWP - Spot Welding Positions
TCP - Tool Center Point
VB - Visual Basics Application
VS - Visual Studio Application
VSTA- Visual Studio Tool Application
1
1. Introduction
In manufacturing industries and production firms, different operations like machining, welding,
assembling are performed on the workpieces. To test the welding operation, the workpiece is
located and held successfully with external forces. The constraining of a workpiece with an
external force is called fixture force or work holding. This way of holding the parts and
components together is considered a prominent issue in many manufacturing industries. In
traditional manufacturing, engineers develop different fixture platforms for different workpieces,
depending on their shapes and sizes.
The Responsive Manufacturing System (RSM) and flexible fixture platforms could change their
fixture orientations to desired directions based on various shapes and sizes of the workpieces
within a certain family of parts and manufacturing operations, which has become a valuable
technique in the industry. The form of flexible fixture is a behavior of any Flexible Manufacturing
System (FMS), and this FMS technique is called automated reconfigurable fixture techniques. The
reconfigurable fixture is one of the most appropriate flexible fixture techniques for a Computer
Integrated Manufacturing (CIM) environment. Reconfigurable and automated modular fixture
employs several fixture modules that are set up, adjusted, and changed to form different fixture
layout.
In the current phase of modern technologies, the new tools are developed or identified for problem-
solving by the designers or the engineers. Engineering design is an iterative process enclosed with
concept design, detailed design and design validation or analysis. Design automation is an
approach used to capture and reuse engineering knowledge and intent. The automation technology
enables to use the rule-based designs, which can be used to drive parameters and attributes of the
design models.
1.1. Background
In the standard designing process, modular fixture systems are an extension of the classical
machinist’s approach for developing a fixture’s variety from the combination of elements like V-
blocks, toggle clams, rectangular blocks etc.…, that is locked to the cast of baseplates (Grippo, et
al., 1987). The term fixture refers to the task of immobilizing a workpiece to perform operations
such as assembly and machining. As such, fixtures are of fundamental importance to industrial
manufacturing. In this project, the reconfiguration of modular fixture elements is done for holding
the required workpiece (B-pillar sheets) in automobile industries.
The CAD world is evolving with the new development’s day by day. Due to the competition in
this field, the data connectivity with different modules and flexibility in utilizing those modules in
working are becoming the route of interest for organizations. A few years ago, Cloud-based CAD
software which gives universal access to data was unimaginable, but now it is becoming more and
more prevalent. Automation in CAD and other various sectors had also been the biggest milestone
in history. Dassault systems has already introduced AI in their CAD systems such as CATIA and
3D Experience. The market also focuses on virtual reality through which the quality of
visualization can be improved, to reduce the gap between 3D models and reality (Gaget, 2021).
2
An American architect and designer, BUCKMINSTER FULLER said, “You never change things
by fighting the existing reality. To change something, build a new model that makes the existing
model obsolete”.
As the world of engineering always thrives on development and innovations, CAD is one of the
major organs of the business world, which will be developing and expanding all the time.
1.2. Problem Statement
For the organizations and companies to decide on which is the best CAD software according to
their requirements within the competitors, this thesis provides a report with the information about
two different CAD applications of Dassault Systems which are CATIA V5 and 3D Experience.
The development of a modular fixture’s platform which can be flexible enough to adjust the
fixtures in required orientations is one of the major requirements of the various product
manufacturing industries, which can be fulfilled with the help of CAD methods. This thesis also
concentrates on the development of robot spot welding operations with advanced CAD methods.
1.3. Literature Review
Modular Fixtures (MF) are the components that are widely used in every manufacturing industry
for an increase in products efficiency and decrease in process cost. But for a long time, one of the
main problems faced in this fixture is the flexibility to use the same MF platform for different
workpieces. During this project, a wide range of articles concerning fixture were studied, including
design of fixtures, fixture modelling and automated fixture planning. It can be seen that; these
topics follow a historical line that is divided into different areas. Most and recent projects in this
topic are from the area of automatic fixture’s design. Fixture’s design became an important factor
in decreasing the production time and cost in the manufacturing process, along which CAD
systems were developed to simplify this design process. Even though the automated CAD systems
for fixtures has been improved, and their techniques were incorporated in CAD, many
manufacturing activities are covered by Computer-Aided Manufacturing (CAM) process
softwares such as tool paths generation, motion tasks, etc. So, to increase the speed, accuracy and
consistency in manufacturing, the CAM is developed and used for handling modular fixtures with
respective workpieces which simplifies the manufacturing process. The development of
automation in the computer-Aided Fixture’s Design (CAFD) and development of Computer-Aided
Fixture Manufacturing (CAFM) has been the focus of this project (Keyvani, June 16, 2008).
Several researchers have focused their work on fixture design information representation.
‘Uday.H.Farhan’ is one among these people whose project’s objective is automation in the design
and assembly of modular fixture’s platform using Solid works Application programming interface
(API) connected to Visual Basics programming language. He used VBA automation to create the
new menus and libraries in a solid works environment for storing and selecting different elements
of the modular fixture platform, which helped him to develop the user interface of solid works API
for modular fixtures (Farhan, 2013).
3
‘Ali Keyvani’ is one among the researchers whose project objective is to implement new methods
based on a new process and plant simulation. A software called “Tecnomatix” is used for the
process simulation in his project, which includes designing, validation and robot simulation in the
modular fixture area, which is specifically used in BIW robotic lines. And this API decreases the
distance and time between design, validation & simulation modules. Ali’s one objective is semi-
automation in the CAD by customizing the new dialogue boxes on the “Tecnomatix” environment
for modular fixtures (Keyvani, June 16, 2008).
Similar research was done on both modelling and analysis of modular fixtures for flexible
manufacturing systems by Vukelic.D. In his project, he modelled mounting frame type modular
fixtures in which there are sliding movements with 6 degrees of freedom between fixture elements
to hold any shaped or sized workpiece. He also differentiated his fixtures model with conventional
modular fixtures and analyzed the stiffness between them using Finite Element Analysis (FEM)
stress analysis (Matejic, et al., 2018).
Ilker Erdem research objective is to identify and increase the efficiency of flexible fixtures in
manufacturing industries. He worked on methodologically finding the usage of efficiency in
modular fixtures design. This study of Ilker Erdem made our understanding of reconfigurable
modular fixtures used in various industry sectors and gave an idea to think for different
perspectives on flexible fixture systems (Erdem, 2017).
1.4. Purpose
The purpose of the thesis is to conduct a comparison between the advantages and disadvantages
of the two software’s used for feasible development of the modular fixtures and spot-welding
operations for the fixture designing of car’s B-pillar workpiece.
1.4.1. Research Questions
• What is the difference between CATIAV5, and 3D experience? Explain with advantages
and disadvantages of the process in each application.
• How can automation in Design and Digital Manufacturing be achieved?
1.4.2. Deliverables
• A significant study on techniques suitable for Computer-Aided Design Automation
(CADA) and Computer-Aided Robot Simulation (CARS).
• Code for design automation of modular fixture platform.
• Code for digital manufacturing automation of spot-welding operation.
• The distinction of Dassault Systems, CATIA and 3D Experience softwares.
• Simulation of robot spot-welding operation on a workpiece (car’s B-pillar).
4
1.5. Delimitations
• For using Visual Studio Tool Application (VSTA) in 3D Experience, the specific version
of Visual Studio community application 2017, must be installed.
• 3D Experience software provided does not have 100 % license access for creating new
products.
• Limitations due to the lack of computer performance for using 3D Experience commits the
software crashes while working.
1.6. Thesis Overview
The overview of report structure from background study to the methods implemented to acquire
the results is mentioned in the below Figure 1.
Figure 1: Thesis overview
Chapter 1
• Introduction: This chapter presents the overall outline of the thesis describing the problem discription, literature review, purpose & research questions, deliverables and delimitations.
Chapter 2
• Theory: The chapter presents all the supporting concepts of the elements of the thesis as a theoratical study.
Chapter 3
• Methodology: This chapter explains what is done and how it is done. It allows to evaluate thereliability and validity of the research and it allows to know the approach used to work in this project.
Chapter 4• Results: This chapter is where main findings of the thesis is noted.
Chapter 5
• Discussion: This chapter explores the significance, relevance, and meaning of our results. It describes and evaluates what we found and shows how it relates to the literature study and research questions.
Chapter 6
• Conclusion and Future Work: This chapter state the answer to the main research questions and summarizes on the purpose. It make recommendations for future works on this topic.
5
2. Theory
2.1. CAD
Computer-aided design (CAD) refers to computers assisting the design process in all kinds of
industries. In CAD, it’s conceivable to build a complete design in an imaginary space, through
which properties like length, height, width, material, and color can be visualized and modified
(Design, 2021).
The CAD program is utilized to extend the efficiency of the drawings, make strides in the quality
of design, make strides in communications through documentation, and make inputs for
manufacturing. CAD results are in the form of electronic records of print, machining, or other
manufacturing operations. Mechanical Design Automation (MDA) or Computer-Aided Drafting
(CADT) are the different terms used for creating technical drawings on a computer. To depict
traditional drafting objects, CAD software usually relies on vector-based graphics. However, raster
graphics would also be used to display the overall appearances of the designed object (V, 2018).
Evolution:
Before the origin of CADD (Computer-aided designing & drafting), engineering drawings were
made on large paper sheets using drawing boards. In the paper drawings, the completely drawn
design cannot be changed. So, if changes in design are required, engineers have to create the
sketches all over again (Anon., 2021).
Figure 2: Evolution of CAD
As shown in the above Figure 2, the father of CAD “Patrick Hanratty” and a man in collaboration
with a machine who made graphical communication system “Ivan Sutherland”, are the roots of the
development of what is today called CADD.
6
“Francis Bernard”, the father of CATIA and “Marcel Dassault”, founder of Dassault aviation, are
the roots of the development in CATIA today. In 1970s, Francis initiated CAD developments at
Dassault Aviation and co-founded Dassault Systèmes in 1981, after he collaborated with IBM to
sell CATIA with windows operating system. In 1984, a young engineer named Bernard Charles
joined the company and founded the research and strategy department for the development of
Dassault Systèmes, who is the present director from 2006 after Francis’s retirement (YOU, 2021).
In the year 1988, an aerospace company, “Boeing”, announced that CATIA will be used for
designing the 777 aircraft. Through this IBM-Dassault made revenue of 1billion dollars. In 1995,
the invention of “SolidWorks” which is the first CAD modeler for windows was successful and
was acquired by Dassault Systèmes in 1997. From 1990, the market’s attentiveness was rerouted
to product data management software, which was successfully used in Boeing’s 777 design in
CATIA.
Since 1981, the advancement in Dassault Systèmes CATIA increased with progress in its versions
till CATIA V5. In 2015, the latest version of CATIA named 3D Experience was built, which is a
platform possible to connect design engineers and their product’s data in the companies with the
help of a cloud database. In 2020, 3D Experience expanded the idea of design from things like
Automobiles, buildings and aero planes to the human body and life with the advent of virtual twins.
Compatibility of CAD systems with all major platforms & devices like windows, Mac, and
digitizing graphics tablets went on increasing. Furthermore, there’s been a lot of developments in
the CAD-human interface interaction from touchscreens to Visual Reality (VR)/Augmented
Reality (AR) (Scan2CAD, 2021).
Types of CAD:
2-Dimensional CAD: 2D CAD that was developed in the 70s, depends on basic geometric shapes
like lines, rectangles, circles, etc. to build levelled drawings.
3-Dimensional CAD: The development in processing power and graphic display capabilities of
computers made 3D CAD a popular design tool. These 3D models can be visualized in isometric
view and rotated in the X, Y & Z axis.
3-Dimensional wireframe & surface modelling: 3D wireframes can be visualized with lines and
arcs. 3D surface models can be visualized as a solid with a minimum thickness limit. They are
more realistic compared to wireframes.
Solid Modelling: has the properties of giving weight, volume, and density to physical objects.
These models designed can be exported in part or product formats and used as inputs to
manufacturing (Anon., 2021).
2.2. Product Lifecycle Management (PLM)
Product Lifecycle Management (PLM) which consists of different entities such as products or
intangible goods, is the process of systematic management of the life cycle for a developing
7
product from the establishment stage to the disposal of the product and control of its product-
related information (Saaksvuori & Immonen, 2008). The main objectives of the PLM companies
are to improve the managing capacity of a life cycle of a product and product-related performance
(Stark, 2011).
Many organizations adopt the PLM concepts and the PLM Systems, as it is gaining access to the
product throughout its life cycle. A single PLM system can support the information related to the
product life cycle and have access, store, and reuse all its product information (Sudarsan, et al.,
2005).
The PLM is integrated with technology like CAD, CAM, and CAE for defining the process. Design
and manufacturing engineers are often benefitted from information about the 3D representation of
the product. Having the vast information in the collaborative space, the information data are
exchanged in the CAE environment, and later the results of the simulation data of the project are
carried on the CAD Modelling. The improvement or the changes required on the product is done
by validating the experimental results and by taking the feedback from 3D Modelling and
simulation of the product (Nosenzo, et al., 2013).
2.3. Fixtures
The fixture design is carried out manually in the normal environment, where heuristic knowledge
is required for the designing and the manufacturing techniques. The fixture design is categorized
based on the degree of automation like interactive, semi-automated and automated systems. The
process of integrating automation for the fixture design has been put into the effort, where we use
these systems, one that automates the selection of fixture points and another one is the position of
the elements using the design techniques and the rule-based design with Artificial Intelligence (AI)
tools (A, et al., 2000).
Considering the configurations and the classifications of the fixture systems, some aspects for
designing the flexible model can be noted. The working model of the fixture system is separated
into sub-elements like locators, supporters, and clamps. These sub-elements have different
behaviors and while designing, one must note the harmony of these elements to make it more
flexible or modular. Many methodologies and guidelines are developed to implement modular
fixture systems to reduce unnecessary costs and increase the knowledge in developing it more
flexible (Z & W, 2010).
Fixtures are important components in the production or manufacturing industries. Many operations
like welding, assembling, machining, and others will take place with the help of fixture platforms.
The quality of the parts produced in manufacturing industries can be improved by using a fixture
platform which increases efficiency and decreases the time and cost consumption in production
(Kumar, et al., 2004).
The initial concept in planning, with the calculation for the cost-effectiveness, resource planning
and layout, instructs the manufacturers to build the assembly setup. To perform this task, engineers
should carry out detailed planning with equipment design, robot simulation, and virtual
commissioning. A detailed 3D model is developed using the CAD software tools along with robot
8
simulation tools which result in the detailed robot movements that are used to create the virtual
simulation of the manufacturing, safety regulations considerations, and concept development of
the production lines (Biesinger, et al., 2018).
2.3.1. Fundamentals of Fixture Design
Fixtures are regarded as tools used to assist in manufacturing on a production line. They are also
one of the resources that process planners can use to plan the production sequence along with many
other types of tools such as machines, transport devices, cutting tools, etc. To produce a part, a
production sequence, lists the operations and sequences that can be followed, along with resource
specifications. In traditional automobile manufacturing, the humans used to assemble the car on
assembly line which can be seen in Figure 3.
Fixture design consists of planning, layout design, elements design, tool body design etc. They
may be developed in parallel, not necessarily as a series of isolated activities in real execution.
Basic fixture concepts that are established during fixture design are:
• Fixture element design is related to the complete details of the clamps, pins, locators and
supports.
• Tool body design produces a structure combining the fixture elements within the required
spatial relationship with the machine.
It is the process of conceptualizing a basic fixture
configuration by analyzing the information that is
available regarding the material and geometry of the
workpiece, the operations, the processing equipment
required for those operations, and the operator
(Kumar, et al., 2004).
The fixture design depends on the size and shape of
the workpiece. The axis system of the fixture’s
platform depends on the surface axis of the workpiece
and its orientation. It also depends on the number of
contact elements required to hold the complete
workpiece. The position of the locators and clamps are
one of the major factors which cause the deformation of the workpiece during machining. The
purpose of a tool body design is to create a rigid structure in which all the components of a fixture
are positioned correctly (Erdem, 2017).
The fixture elements should be structured in such a way as it illustrates the relationships between
them and how they are assembled. To prevent damage to the fixtures from machining forces, it
must be designed to withstand those forces. It is important to construct fixtures, as well as parts,
in such a way that they can hold the workpiece securely, as well as robust enough to handle the
forces generated by the tool. If possible, these forces ought to be directed towards clamping the
workpiece (Erdem, 2017).
Figure 3: Traditional Fixtures in Automobile Industries (Volkswagen, 2020)
9
2.3.2. Modular Fixture
A MF platform is a flexible alternative to a single purpose fixture system. With the help of re-
oriented clamps and pins, the fixture’s platform can easily reconfigure for any work holding
application. Assembling and disassembling this fixture’s platform is also easy with the help of a
screwing and pivoting mechanism. Originally developed in the late 1960s, modular fixture systems
are primarily used in conjunction with CNC machines. Until the advent of multi-axis CNC
machines, their use was not widespread. There are different types of MF kits; each of these
components belongs to one of the types: baseplate, locator, clamp, and connection. One can create
a customized fixture by assembling the components from the kit (Jonsson & Ossbahr, 2010).
Modular construction implies assembling the standardized sub-assemblies. For example, in
automobile engines, a self-contained unit comprising many parts is a module. Similarly, the
modular automobile consisting of multiple elements like spark plugs, carburetors, fuel pumps and
anti-friction bearings is a module. Modules are toggle clamps comprising links, pivots, and
adjustment screws. Essentially, components of a swinging hook clamp, such as the spring, the stud,
and the nut, is a module. In this sense, all the standardized parts in fixture contact elements of this
treatise can be considered as modules; and all the fixtures that go in connection with them can also
be considered modular (Joshi, et al., 2010).
At each pointed position, the fixture elements act as the contact elements between the workpiece
surface and the fixture’s baseplate. This employs a supply of elements (or modules) to construct
the fixture layout by connecting (or bolting) the elements to a baseplate, which usually have tapped
holes. The alignment of the whole fixture platform on the baseplate depends on the workpiece
placement. The elements have the rotational movement for fixing the workpiece on the modular
fixture’s platform. They must be designed in CAD for the total construction of the fixture’s
platform. Nevertheless, this design may require a lot more time and effort than just constructing
the fixture elements to its platform (Shirinzadeh, 2002).
2.3.3. Reconfigurable Fixtures
The concept of reconfigurable fixtures uses elements that can be rearranged or reconfigured to
create layouts that position and hold different workpieces within a family (Bejlegaard, et al., 2018).
A robot or dedicated electronic manipulator usually performs the reconfiguration or
rearrangement. A robot retrieves elements from a storage magazine and places them on a platform
to generate a fixture layout. The platform can be a baseplate or a T-slotted plate with plain and
tapped holes. In reconfigurable fixtures, the robots are used to perform quick adjustments to fixture
bodies and locators (Erdem, 2017).
Rebuilding means physically removing or reattaching fixture components, while reconfiguring
implies that some components are adjustable. However, the line between modularity and
reconfigurability is not clearly defined, and many hybrid solutions exist. Although a reconfigurable
fixture could also be restricted in many geometries it can conform to, reconfiguration is often done
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more quickly. For fixtures to be reconfigurable, they have to be designed to accommodate families
of products during a single fixture which will be efficiently converted to different product variants,
while also enabling the fast introduction of new products, since product families change over time
(Bijan, 2002).
Reconfigurable modular fixtures are a combination of both modular and reconfigurable fixture
systems, where the supply of modules of fixture elements can be rearranged in required
orientations to constrain different workpieces. In this, there exists a library of various fixture
elements, as the basic fixture elements include vertical and horizontal clamps depending on the
surface of the workpiece. The contact points on the workpiece selected in a CAD environment to
define fixture element’s locations (Jonsson & Ossbahr, 2010).
2.3.4. Units of Modular Fixture Platform (MFP)
The MFP has been subdivided into 6 different units such as clamps, locators, holders, cylinders,
pillars, base and control units.
• Clamps: A clamp is a device used to hold the workpiece against the locator and to resist
the effects of the welding force. The size of the clamp should be large enough to hold the
workpiece, on the contrary, it should be small enough to stay away from collisions that can
occur in the tool path. Here, L-shaped rectangular clamps are used to hold the workpiece
from the top axis (Farhan, 2013). This also helps the workpiece secure under vibration,
loading and stress and provides damage prevention to the workpiece. The direction of
clamps should be determined according to welding forces direction to perform machining
operations securely. Clamping forces should be in the same direction as the machining
forces, which try to push the workpiece in opposite to the machining direction onto
supports (Farhan & Rada , 2011). The designed representation of the clamps, locators &
their supports used in the whole modular fixture’s platform design used in Volvo car
industries is shown in the below figures.
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Figure 4: Clamps Assembled to Holder
• Locators: A locator is a fixed component of the fixture that constrains a parts movement
while maintaining its position in the fixture. In coordination with the supports, locators
define a unique way of keeping the part in the correct position and orientation. Here, the
pin-hole locators are used for the concentric locating of the workpiece through a modular
fixture’s platform (Keyvani, June 16, 2008). They are used to restrict the degrees of
freedom of the workpiece by locating the pins in the holes existing on the workpiece
(Farhan & Rada , 2011). Depending on the type of holes on the workpiece, the number of
DOF can be constrained. For example, to a circular hole, the locator can constrain the X &
Z axis, whereas to a slot, they can constrain only the Z-axis and the X, Y-axis will be free.
So, the locators should be strong enough to secure the workpiece against the welding forces
(Kumar, et al., 2004).
Figure 5: Locator
• Supports: Holders, cylinders and Pillars are the supporting elements that will be in contact
with the other fixture elements that are clamps and locators. Clamps, locators, holders,
cylinders, and pillars are the modules that are used to construct a modular fixtures platform
and these modules will be connected using a screwing mechanism. Pillars have an angular
movement so that the clamps connected to them can get the angular movement for
reconfiguration of fixtures. Holders are movement less supports as they are connected to
locators to hold them straight up in a vertical direction. Pillars are the main supports of the
fixture systems, which stands to carry and support the other elements of fixtures on the
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fixture base plate layout. Supports are added and placed below the workpiece to prevent or
constrain deformation.
Figure 6: (A)Clamp Support Figure 7: (B) Locator Support
• Base Unit: The base plate or unit is the main structure of the MFP which carries all the
fixture components on the flat plate. There are different types of baseplates such as
rectangular plates, circular slotted plates, square pallet plates, T-slotted plates, vertical
angle plates etc. (Resources, 2021). Some types of plates have grid threaded holes which
will be protected from the chips by set screws (Book, 2021). Baseplates are manufactured
with a variety of materials like aluminium, cast iron, granite. Two types of modular fixture
systems accessible today in industries are baseplates with grid pattern holes and T-slots.
MFP with grid pattern holes has more advantages and accuracy compared to the T-slotted
plates (R Rzasinski, 2018). But T-slotted plate can be used according to the requirements
as it gives the movement along with the slot to components connected on it. Hydraulic
power work-holding is one of the modular fixture systems which used standard, off-the-
shelf power work-holding components. Adoption of these fixture systems reduce the cost
investments and provide more possibilities or options in designing (Resources, 2021).
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Figure 8: Base Unit
• Control Unit: The Control Unit is the valve box that is used to operate the fixture with
hydraulic and electrical connections in MFP to cylinders, holders, etc. This is the power
supply that is utilized to move the elements or components of fixtures in required
orientations. This also helps in assembling and dissembling the fixture elements on the
base unit.
Figure 9: Control Unit
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2.3.5. Three-Two-One Method
Most of a fixture designer's time is spent deciding where the workpiece should go in the fixture.
For solving this problem, one can use the 3-2-1 principle that consists of 3 steps that employ
initially three points, then two points and then one fixed point, which is why it is also called the
six points methods. (Anon., 2009)
There are twelve degrees of freedom for any free body, as follows:
6 are translational degrees of freedom:
- +X, -X, +Y, -Y, +Z, -Z directions
6 are rotational degrees of freedom:
- Clockwise around the X-axis (CROT-X)
- Anticlockwise around the X-axis (ACROT-X)
- Clockwise around the Y-axis (CROT-Y)
- Anticlockwise around the Y-axis (ACROT-Y)
- Clockwise around Z-axis (CROT-Z)
- Anticlockwise around Z-axis (ACROT-Z)
To locate the workpiece in the fixture, all 12 degrees of freedom except for three transitional
degrees of freedom (-X, -Y, -Z) must be fixed. The workpiece must therefore be fixed in 9 degrees
of freedom.
By using the 3-2-1 method these degrees of freedom can be fixed in the workpiece to modular
fixtures platform. The process of locating the workpiece using a 3-2-1 principal fixture is explained
in the steps below.
Step-1: Place the workpiece on three non-collinear points of the bottom surface (XY), and it is
able to fix the degrees of freedom +Z, CROT-X, ACROT-X, CROT-Y and ACROT-Y.
Step-2: Place the workpiece at two points of the side surface (XZ) and it is able to fix the +Y and
ACROT-Z degrees of freedom.
Step-3: The +X and CROT-Z degrees of freedom can be fixed by placing the workpiece at one
point on the adjacent surface (YZ).
Using the 3-2-1 principle of fixture design, you can fixate 9 of the required degrees of freedom
(Anon., 2009). The 12 degrees of freedom can be seen in below Figure 10.
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Figure 10: Twelve Degrees of Freedom
2.4. Digital Manufacturing
Production planning plays a significant role in the development of manufacturing industries. An
increase in customer needs and changing demands in the products gives the manufacturing system
a challenge of evolution in terms of methods or innovation in the modern manufacturing society.
Flexible manufacturing and customization are integrated into the modern manufacturing society
to improve the system’s responsiveness to meet the market demands ( Wang, et al., 2011).
Satisfying the demands of the system, strategic and tactical designs methods are focused on the
improvement of the existing manufacturing systems using simulation methodologies. A simulation
is a powerful tool that can mimic the dynamics in a real-time system. As stated by Shannon (1975),
simulation is “the process of designing a model of the real system conducting experiments with the
model designed for the purpose of understanding the behavior of the system or evaluating the
strategies based on the operation of the system” (Ingalls, 2011). In the product and production
engineering process, simulation is a key to create an overall virtual model on the different levels
of product realization.
Digital manufacturing can be considered a highly promising set of technologies for the
development of products in terms of development time or cost, addressing the increasing product
quality and needs of customization. Together with the help of digital manufacturing and high-end
simulation, the development of the integration of computer-based simulation, 3D visualization,
analytics, and collaborative tools to create products and the manufacturing process. Evolution of
the digital manufacturing ensued from the manufacturing initiatives like a design for
manufacturability (DFM), computer integrated manufacturing (CIM), Flexible manufacturing
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systems (FMS), etc., to design the 3D simulation for the complete production line and the variants
of the production process ( Seimens, n.d.).
Figure 11 (Myung, 2003) shows different domains of the applications of the digital manufacturing
process in various designing fields. In manufacturing engineering, the digital manufacturing
process provides support from designing to the marketing of the products, involving different
domains of product development, Virtual manufacturing, Robot Simulation, and Ergonomics
analysis, etc. Digital manufacturing unifies the various operation technologies and information
technologies to develop smart products while reducing the resources required in the inventory
process (Myung, 2003). The digital factory that consists of digital modelling and simulation tools
are employed to increase the productivity of the manufacturing cell with the integration of robot
automation. The Robot Simulation environment is applied to configure the 3D simulations of
different tasks and operations of manufacturing processes and analyze them to configure the
collision-free robot paths (Caggiano, et al., 2018).
Figure 11: Domains of the digital manufacturing process
Robot simulation is the simulator used in the manufacturing process that helps to create robot
applications for the industrial plant layout. This evolution of robots was started in the year 1961
with the invention of “UNIMATE”, the robot arm used to pick and place objects, materials, and
parts in industries. “George Charles Devol”, grandfather of robotics made this invention of the
first digitally operated programmable robot arm. Since then, the development in robotics has
progressed widely over the world. Today robots are utilized in industries for doing more precise
operations such as spot-welding, assembling, etc., due to which the efficiency in the production
increases.
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CARS is used to design a robot manufacturing process (RMP) with the help of CAD software,
through which the cost and time investments can be reduced in the manufacturing process.
Industrial robotics is the combination of numerical control technology (NCT) and teleoperation
technology (TOT) through which the robot can be controlled. In NCT, it can be programmed with
the numerical code, whereas in TOT, it can be operated by a human with the help of its computer
controls (Myung, 2003).
2.5. Body in White (BIW)
The body in white (BIW) stage in automobile manufacturing involves joining the chassis and body
of an automobile together before painting and before the motor, chassis subassemblies (glass, door
locks, handles, seats, upholstery, electronic, etc.) are integrated into the structure. The assembly
includes a variety of techniques such as welding (spot, MIG/MAG), riveting, clinching, bonding,
and laser brazing. The name “body in white” is derived from the car body after it is dipped into a
white bath of undercoat paint (primer). The term BIW might also refer to timber that has been used
for car bodywork. Basically, all materials, such as timber, furniture, etc., are considered "in the
white" when they are raw and unfinished (Pradeep & Pilla, 2017).
BIW makes up about 27% of a car's curb weight, and it affects the car's performance greatly. It is
possible to construct BIW in two different ways: monocoque structures, in which all body
members carry the load while the chassis is integral to BIW and integrated with each other, and
body-on-frame structures, in which the frame carries most of the load. There are several significant
properties expected of the BIW. Among other things, it should have high tensile strength, and be
stiff in bending, torsion, static, and dynamic modes. As well as providing good quality safety for
the car body and its occupants, it must also meet U.S. Federal Motor Vehicle Safety Standard 208,
which ensures the safety of the passengers from accidental crashes, whether it be front, rear, side,
or even rollover (Pradeep & Pilla, 2017).
To improve fuel economy, lightweight materials should also be used in the body in white (BIW),
as it represents a significant portion of a car's weight; in addition, given environmental concerns
in recent years, it is also expected to be recyclable. The B-pillar which is the main component of
this project will join the body frame of the car in the body in white (BIW) stage of automobile
manufacturing (Pradeep & Pilla, 2017). The BIW of the car can be seen in below Figure 12.
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Figure 12: Body in White (Volvo, 2014)
2.5.1. Car B-pillar
In a vehicle, the B-pillar is the pillar attached to the rear of the forward door. Designed to keep the
pillars between the front and rear doors from obscuring the view from the offset rear, the B-pillars
curve inward following the contours of the seat frame. The pillar is primarily intended to protect
passengers in lateral collisions, so controlled deformation of the pillar during a lateral collision is
recommended for the best possible protection of passengers. The B-pillar is shaped from a planar
steel blank and is of substantially hat-beam shape with varying cross-sections along its length. The
top of the pillar is shaped as a transverse profile, which acts as a fastening portion adapted to being
welded to the longitudinal roof member of the vehicle. A transverse profile is carved into the
bottom of the pillar and represents a fastening portion. This portion is designed to be welded to the
vehicle's sill member (Bodin & Berglund, 2012). Roof and sill members are the upper and lower
fastening portions of the car door, between which the B-pillar is welded as a supporting pillar for
the car body frame. The B-pillar supports the roof as well, but the safety belt mechanism for the
front seat is hidden behind the B-pillar between the front and rear doors. By spreading forces away
from car occupants, also helps during side impacts. Various holes on the pillar are necessary, e.g.,
those for fastening the rear door hinges and the striker plate for the rear door lock, as well as a hole
where the cable leads will pass through (Bodin , et al., 2012).
Adding the B-pillar to the vehicle body is the last step of completing the car body structure. These
installations can be called panel side outer and panel side inner, which are integrated as Body
frame inner (BFI) and Body frame outer (BFO) in BIW.
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2.6. Knowledge-Based Engineering
The knowledge-based system (KBS) programming methodology offers a convenient way to
encode the heuristic knowledge of human experts. In a manufacture’s product development, the
need to capture, manage, and utilize design knowledge and automate the process gives the unique
experience to the development of knowledge-based Engineering technology (Sainter, et al., 2000).
According to J.K. Debenham (1988),” Knowledge Engineering is the process of developing
knowledge-based systems in any field whether it be in the public or private sector in commerce or
in industry.”
Knowledge-Based Engineering (KBE) is a never-ending research field that promotes the
application and the reuse of the process engineering knowledge through various studies of
technologies and methods with the objective is to improvise the various aspects in the development
of the products and their process (Verhagen, et al., 2012). KBE represents the connection of
various disciplines like artificial intelligence (AI), CAD and computer programming (Rocca,
2012).
Automotive, aeronautics and general engineering industries are well known for knowledge and
their expertise, spread in various divisions. The field engineering product development integrates
multiple disciplines like weight, stress, aerodynamics, design, tooling, manufacturing, etc., the
development of this knowledge is comprised in different stages are carried out using commercial
systems like CAD, CAE, PLM systems. (Holla, 2018)
In product development technology, the knowledge of engineered products and their design
process is embedded in a system known as the KBS system, which can be reused in the
development of similar products. (Holla, 2018)
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3. Methodology
The methods for developing the modular fixtures platform assembly and spot-welding operations
on car B-pillar has been divided into two stages in this project. Automation in designing and robot
simulation are the two stages that are used to develop the modular fixture’s platform. This
workpiece (Car’s B-pillar) needs to be fixed flat by the Modular Fixtures Platform (MFP) with the
help of fixture elements to secure it from wobbling and tottering when implemented with
manufacturing operations such as spot-welding, machining, etc. This is the quantitative research
approach through which information can be collected and categorized by working and testing in
the CAD softwares. This can be done using Dassault Systems CAD applications, which are
CATIA, and 3D Experience. In this approach, the existing basic data on CAD applications and
modular fixtures that are used in automotive industries can be used as the input sources for design
automation and robot simulation.
3.1. Project workflow
The activity or method of the project is shown in the below Figure 13, the method study is carried
out with the data collected from study results of Design automation and robot simulation through
the CATIA V5 and 3D Experience softwares. In the initial stage, the problem of the thesis is
understood, and a literature study is done to come up with the methods that can solve the problem
and satisfy the purpose. The automation of design and robot simulation of modular fixtures
assembly is done using Excel and Visual Studio applications for coding by referring to the data of
V426 modular fixtures. The results of DA and RS between CATIA V5 & 3D Experience are
compared and explained with the differences in the Results part.
Figure 13: Overall Project workflow
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3.2. Design Automation (DA)
In the current phase of modern technologies, new tools are developed or identified for problem-
solving by the designers or the Engineers. Engineering design is an iterative process enclosed with
concept design, detailed design and design validation or analysis. Fundamentals in the design
process need consistent management, relations, constraints, dependencies, and domain knowledge
while associating with the products.
Now a day’s automation has become the most important work in the manufacturing industries due
to its advantages like reduced human labour costs and expenses, improved quality, increased
consistency of outputs, reduced cycle time and increased accuracy. DA helps to manufacture much
easier, as it enables engineers to capture and reuse the engineering knowledge and intent. DA not
only helps in reducing errors and time spent on tedious, repetitive modelling tasks, but it can also
be scaled to streamline downstream development processes.
In this project, the API used for automation in CATIA is Visual Basics and in 3D Experience in
Visual Studio. They are used for coding and executing design generation. More explanation about
these tools is added in the later contents in methodology. The DA is used to create the MFP which
can be reconfigurable or reoriented according to the workpiece.
In the previous research articles, the decision of the clamping positions has been determined by
the researchers by using 3-2-1 methods. Whereas, here there is no need for that, as the pointer
positions for clamping and locating on the workpiece is provided by the VOLVO R & D
Department. These pointed positions are denoted with X, Y, Z in the CAD model and are located
inside every part in a geometrical set named “Master locating systems”.
The Design automation process for MFP has been divided into 6 different modules such as axis
reference creation, clamps instantiation, holder’s instantiation, pillars instantiation, locator’s
instantiation, and locator-pillars instantiation in which the coding process will be similar to the
changes in the loop values. As the given master locating positions carries no geometry, the module
called “axis reference creation” is generated, which consists of the code to create an axis system
on the master locating positions to use them as the geometric reference for the instantiation process.
This separate creation of modules helps the design engineers for easy understandings and doing
modifications in the code. Any problem related to a specific MFP part can be solved by modifying
the code in the respective module.
The automation process to design MFP can be seen in the below Figure 14,
22
In the flowchart above, the design automation process used to develop the modular fixture’s
platform has been explained.
Step-1: Firstly, the part document that consists of the point references of master locating or
clamping positions will be called in the GET PART stage.
Step-2: FOR LOOP is used to select all the master locating positions in an order starting from
value 1 and ending at the last position in the no of references, which is denoted with variable “i”.
Step-3: IF LOOP is used, give conditions to “for loop”, in such a way that only the specific required
positions will be selected in sequential order. If the condition satisfies, then the chain will continue
to create the new part, otherwise, it will go back to for loop to select the next position in the order.
Step-4: The new part document will be created inside the new product and will be named with the
numerical value of “i” in the PART CREATION stage.
Step-5: In the COPY & PASTE OPERATION stage, the selected master locating axis systems in
the loop will be copied and pasted in the newly created part inside the first geometrical set.
Figure 14: Flowchart for Design Automation
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Step-6: Now, the Instantiation is done by considering the copy-pasted element as the reference
location of the instantiating part in the new part document inside the new geometrical set.
Step-7: The new axis system is created inside the new part document as per the required clamps
orientations in the AXIS CREATION stage.
Step-8: Finally, the axis transformation of the instantiated part will be done on to the previously
created axis system to get the part in the required orientation by using AXIS TO AXIS
TRANSFORMATION.
The parts of MFP such as clamps, locators, holders, cylinders, pillars, and base units are designed
separately with the required parameters, and then they are instantiated to make the complete
assembly of the MFP with the required clamps and locator orientations on the workpiece (B-pillar).
After axis transformation, the loop continues until all points are plotted. All the parts of MFP are
instantiated into the separate product named from Child_001(1st child) to 004(4th child).
The whole design and assembly of the modular fixture’s platform done in CATIA V5 are shown
below in Figure 15.
Figure 15:Modular fixture Design using CATIA V5
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3.2.1. Modeling Apps
Part design (PD) and Generative shape design (GSD) are the two 3D modeling applications of the
CAD software packages which are used for the product, part & component designs. These are also
termed as modules of CAD software. PD is used for solid modelling with mass and volume
whereas, GSD is used for surface modelling using curve tracing which has a large set of tools for
creating and modifying the complex shape design & styling. Although both are used for the solid
and surface designs, GSD provides more tools as compared to PD.
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3.3. Robot Simulation (RS)
In the digital manufacturing/robot simulation, the main task is to define the structure of the plant,
lines, station, and resources in a 3D space and relate all these together by several operations to
show and verify the flow of products and resources. The main appliances in each project are
products, resources, and operations. Generally, in the automobile industry, the car body parts are
called products, whereas the robots, risers, weld guns etc. are called resources and the directives
of how to assemble the car parts using resources are called operations. There is another appliance
called simulation which shows the visual representation of spot-welding operation.
The RS here is used to plan & design the process of spot-welding operation on the workpiece (B-
pillar) which is held on the MFP. This spot-welding is done for joining the different car pillar
sheets together and it also joins the Panel Side Inner (PSI) and Panel Side Outer (PSO) of B-pillar
sheet parts. This spot welding is done with the help of a weld gun connected to the ABB robot
arm, which is called Robot Spot-Welding Operation (RSO). The position of spot welding is
decided by the R & D department of VOLVO cars and the cloud of weld guns connected to those
positions has been provided in the data. CAD software’s, CATIA V5 and 3D Experience in
connection with VB & VB.Net programming languages are used for the automation of robot
simulation.
In the development of manufacturing history, robotic manufacturing has been the biggest
milestone through which the efficiency in the production increased and the physical efforts of
humans in dangerous manufacturing sites has been decreased. The robots used in industries are
programmable, multifunctional manipulators which will perform many tasks by moving materials,
tools, or specialized devices through programmed movements. With the help of Robot Simulation
Automation (RSA), most of the real-time errors can be observed and estimated through robot
simulation applications. Due to this design stage of robot simulation, the efficiency can be
increased, and the time and cost can be decreased in the industrial manufacturing process.
The process of planning for robot simulation is shown in below Figure 16,
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Figure 16: Production Planning Process
A Process, Product and Resource (PPR) context allows to create a manufacturing context, which
contains products, processes, manufacturing systems, and physical resources. PPR is a
fundamental building block in Dassault systems that stores any kind of PLM entity used in the
digital manufacturing process. Manufacturing layout/footprint is created within the selected area
in the robot simulation module. The manufacturing footprint can be seen as a floor on which all
the manufacturing operations takes place. The workpiece held on the MFP, robot, weld gun and
riser are adjusted or snapped on the manufacturing footprint of the apparatus by positioning in the
required orientations. The weld gun is connected to the robot arm at its Tool Center Point (TCP).
The flow of the process shown below is a representation of Visual Studio scripts used for Robot
Simulation. The automation process to design the RSO can be seen in the flowchart below,
27
Step1: With the help of references, Visual Studio will identify and connect with the CATIA open
document in the IMPORT CATIA_APPLICATION stage.
Step-2: The part document that consists of the point references for spot welding positions (SWP)
will be called in the GET PART stage.
Step-3: Spot weld trajectory which selects and contains the spot weld positions will be created in
CREATE ROBOT SPOT TRAJECTORY stage. These trajectories are similar to the tag groups
that consist of tag points inside them.
Step-4: The new robot spot task will be created in CREATE ROBOT TASK stage.
Step-5: FOR LOOP is used to select all the SWP in an order starting from value 1 and ending at
last position in no of references, which is denoted with variable “i”.
Figure 17: Flowchart for automatic robot simulation
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Step-6: In the SELECT SPOT WELDS IN TRAJECTORY stage, all the selected SWP will be
added to the previously created spot-welding trajectory. These SWP are in the form of points inside
the group named “Frame of reference” in the product called V426_PAT_JOINING.
Step-7: By attaching the spot weld trajectory as the robot path for welding, the robot motions, and
the spot-welding operations for every SWP will be created with the “for loop” in CREATE
ROBOT MOTIONS & SPOT-WELDING OPERATIONS stage.
Step-8: For loop will continue with the execution of this whole process using another “i” value in
the sequence till the loop ends.
Step-9: With the help of the “Teach” option, the robot task that is created in step-4 can be modified
according to the requirement in this TEACH TASK stage.
Step-10: Finally, the robot task simulation can be executed, and the graphical representation of the
robotic spot-welding process can be observed in 3D space in the RUN SIMULATION stage. The
run time of the simulation can be adjusted in the simulation window, and it can be seen at different
speed levels.
Before teaching the robot task, the singularities in the robot must be checked in the robot jog and
the home position of the robot must be adjusted accordingly. The different configurations of
kinematics and joint values of the robot can be modified in the jog mechanism to avoid the
singularities and incapability to reach. Through this, one can avoid the collisions between robot
and workpiece (B-pillar).
The constructed apparatus in the 3D Experience Robotic simulation model is shown in the below
Figure 18.
Figure 18: Design of Production Planning
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3.3.1. Modelling Apps
Device Task Definition (DTD) and Robot Spot Simulation (RSS) are the two 3D industrial design
applications of the CAD software packages which are used for production planning, process
planning & manufacturing operations. The DTD is the application of CATIA V5 software and
RSS is the application of 3D Experience software. Unlike DTD, the RSS application is only used
for the spot-welding operation.
3.4. VB (Visual Basics) and VB.net:
In VB, Excel is used as a medium to store and execute the scripted program through macros. To
get access to the Visual Rudimentary editor, we must ascertain that the Developer tab is visible.
To make it visible, the developer has to be selected in the file-options-customize ribbon. Then the
macros will be enabled by selecting “enable all macros” in macro settings, which is in trust centre
settings in Excel. Then the Visual Basic editor can be opened from the developer tab. To connect
the excel VB editor with CATIA V5, all the CATIA dependencies from the references option in
the tools tab will be checked. Now, the VB macros can be used and applied to the part in the
CATIA window.
A macro is a series of functions inscribed in a scripting language that is grouped into a single
command to perform the requested task automatically. If you perform a task perpetually, you can
capitalize on a macro to automate the task. Macros are habituated to preserve time and truncate the
possibility of human error by automating recurring processes, standardization, amending
efficiency, expanding CATIA’s capabilities, and streamlining procedures.
There is a procedure to write the code in VB which is a block of statement that is enclosed by a
particular declaration statement and an End declaration. Declaration verbalization is, as
indicatively insinuated by their denomination, used to declare something such as a variable or a
constant. VB supports two types of procedures.
1. Sub procedures, which perform an action in Excel. The declaration verbal expression that
commences a Sub procedure is “Sub”.
2. Function procedures, which carry out calculations and return a value.
Sub procedures do not return a value, but function procedures can perform certain activities before
returning a value.
VB.net means Visual Basics. Network Enables Technology, which is a modern, object-oriented
language that replaced VB6 (Visual Basics version 6). It uses common language runtime (CLR)
component of .Net framework. CLR uses better code translation just in time compiler. Unlike VB,
it does not support backward compatibility and in this the data is handled using ADO.net (ActiveX
Data Objects) protocol.
This VB.net works in connection with Microsoft Visual Studio (VS) application, which is an IDE
and used to develop computer programs, website, mobile apps, operating systems, mechanical
designs, games, etc. Windows Forms, which is a software development platform in VS, is used for
programming the design in connection with 3D Experience. Windows Forms is a class library that
includes .Net frameworks, which provides access to develop the client applications. This class
library is used to control the program using windows controls like buttons, textbox, checkbox, and
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list view, etc. Different modules can be added under the Windows Form, and they can connect and
operate with the form using control button.
In VS, the definitions can be imported before starting the code, through which the requirement of
writing the “Namespace” for every definition can be avoided. Unlike VB, here every variable used
must be defined with its respective interface reference. The importing of definitions can be seen
in Figure 19.
Figure 19: Import definitions in VB.Net
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4. Results
4.1. Comparison
The differences observed in 3D Experience and Catia V5 while working on Design automation
and robotic simulation are explained below.
4.2. Design Automation:
As explained in methodology, for this comparison study, design automation and robot simulation
are chosen as the two main methods. In design automation of modular fixtures application called
"Generative Shape Design (GSD)" is used in both CATIA V5 and 3D Experience. In fact, GSD is
used to design models based on the combination of wireframe and extensive multiple surface
features, with full specifications. In 3D Experience, GSD incorporates all the functions and
command options from CATIA V5 GSD. 3D Experience expanded and developed an extensive
set of tools for creating and modifying mechanical surfaces used in the design of complex shapes
such as Tool Sweep, etc. Tool Sweep can create 3D shape by moving a symmetrical 2D profile
along a specified path in 3D area. The comparison between this application in both software is
explained first.
Figure 20: Tool Sweep in 3D Experience
3D Experience interface is clearer compared to CATIA V5. 3D Experience interface is revamped
and has transformed to a sleeker and more modern look. Instead of complicated top bars with
multiple menus and options, 3D Experience got a change in the top bar with five icons, a search
bar, and an ultra-handy compass. These five icons put back all the functionalities that were
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available within the CATIA V5 top bar menus. The five icons have named Me Menu, Add Menu,
Share Menu, Home Menu, and Help Menu that can be seen in Figure 21.
Figure 21: User Interface of 3D Experience
Figure 22: User Interface of CATIA V5
In Me Menu, all the information related to the designer and the design window can be checked. In
Add Menu, a designer can create and add content by importing different file types such as 3D
XML, CATIA files, STEP files, IGES, STL, etc. In Share Menu, a designer can save and share the
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file created by exporting in different file formats to the personal computer or the collaborative
workspace, or the 3D Experience community also. In this one of the unique features exist through
which, a designer can communicate with other designers instantly in 3D Experience by using 3D
messaging. In-Home Menu, a user can switch to other collaborative spaces and roles that are
connected with his 3D Experience account. Help Menu is where the user assistance can be received
by using options such as Get started, Help, User's guide, Tutorials, and support community.
The search bar, which is called 3D search in 3D Experience is used to find the information on the
3D Experience platform and is connected to the cloud base. So, it helps in finding all data and
metadata stored in the 3D Experience platform and a user can also filter data through a 3D
Experience unique tagging system called 6WTags that categorizes objects by who, what, when,
where why, and how criteria.
3D Experience compass is the gateway to all the user's applications according to roles for both
web and native apps. Users can simply click on quadrant compass and access through any
application in 3D Experience software. Whereas in CATIA V5, a command toolbar will be
accessed by choosing the required workbench from "Start Menu" on the top bar. These can be
observed in the above figures.
In CATIA V5 the command options are set in their respective toolbars that can be shown/hidden,
rotates, and moved on the model window that is shown in Figure 22. To minimize the space
occupation of toolbars on the model window, some of the command option toolbars are hidden
most of the time while working which can be seen in Figure 24.
In 3D Experience, the command option icons are larger and more intuitive. The toolbars that are
specific to the active application are pinned at the foot of the window in what's called "Action
Bar". Multiple toolbars that are divided according to their functions are categorized in their
respective tabs in the Action Bar. 3D Experience provides the option to edit and customize the
action bar. The Tabs that exist in GSD are Essentials, Wireframe, Surface, Volume, Transform,
Refine, View, Tools, Touch. Unlike CATIA V5, if the input is not recognized by the command
bar, it shows the window with suggestions of similar commands to the original input.
Figure 23: 3D Experience Action Bar in Generative Shape Design
Figure 24: CATIA V5 Action Bar in Generative Shape Design
As shown in the design automation flow chart in methodology, the difference between CATIA V5
and 3D Experience design automation process according to that flow chart is explained below.
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4.2.1. Comparison between codes
Get Part Document
In 3D Experience, the get part document step is done using a function code-named "GetPart" and
its working definition is "PLMOpenService". This working definition is used to open the PLM
entity that exists in the active design model window by using part or product entity names. This
identifies the name of the part entity from the model and then opens that respective named entity
from the 3D Experience collaborative database search. The "Return" statement is used to return
the code execution from the "Get part function" to the "Part1" line in the "sub" as shown in the
Figure 25. This type of function must be used in 3D Experience because the software works in
connection with its database.
Figure 25: GetPart Function in Visual Studio for 3D Experience
Whereas in CATIA V5, it is easy to call any part or product entity directly by just setting the active
document and call with the required item name and its type as shown in the figure below. Here, in
the first line of calling active document, VB is connecting with the CATIA application and
selecting the active CATIA document from the app. This active document will be referred to as
the model location to select the required part or product with the help of their respective entity
names.
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Figure 26: GetPart in Visual Basic for CATIA V5
Part Creation
In 3D Experience, part or product creation can be done by using the working definition called
"PLMNewService", which works to create new PLM entities such as 3DShapes, parts, products,
etc as shown in the figure below. Then the created part will be made as the active working object
to do any design operations inside it. By using a working definition called "VPMReference", the
created part will be converted as the child of the main product in the active window. The detailed
code for this can be seen in Figure 27. The salient point here is, most of the academy student
versions of 3D Experience don't have complete software licenses, due to which the creation of
products through automation is not possible in our project.
Figure 27: Product Creation in Visual Studio for 3D Experience
Whereas in CATIA V5, it is easy to create the part or product directly by using a string called
"AddNewComponent", which creates any kind of entities like part, product, etc by mentioning the
type of that entity to it. Then the part will be named and numbered as required, to call it with its
part number whenever it is required to be used. To do any kind of design operation in that part, it
can be simply called with its number. The detailed code for this can be seen below.
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Figure 28: Product creation in Visual Basics for CATIA V5
Copy-Paste Operation
In 3D Experience, copy & paste is done by selecting and adding the required items or elements to
the copy list and then pasting them in the required part, by selecting that part and adding it as the
paste location. The paste operation is done by using the function called "PasteSpecial" through
which the designer can define if the elements should be pasted as the results with the link or without
the link. The same process is followed in CATIA V5 using VB. There is no difference in this step.
But, in VB.Net for 3D Experience, the copy & paste operation is not necessarily used because the
new part is not created for the instantiation. The codes can be seen in Figure 29 & Figure 30.
Figure 29: Copy & Paste in Visual Studio for 3D Experience
Figure 30: Copy & Paste in Visual Basics for CATIA V5
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Instantiation
In 3D Experience, instantiation (powercopy of 2D & 3Delements) is done by using the working
definition called “InstanceFactory” through which the instantiation is possible in the required
location from one part to another part. Though the power copy part is not active, instantiation can
be done by finding the power copy part from the 3D Experience database by defining the location
with its name and version.
This is the same process in CATIA V5 using VB. The only difference is that here the location will
be defined from the personal directory and in 3D Experience the location will be defined from the
database. The codes are shown in the below figure.
Figure 31: Instantiation in CATIA V5 & 3D Experience using VB & VB.net
By using this instantiation code all the fixture parts required are instantiated onto the B-pillar
workpiece and the complete assembly of the modular fixtures platform is done.
Axis Creation
In 3D Experience, the axis creation is done by using the working definition called "Axis System"
through which the new axis systems can be created on the 3Dspace with the help of 2D references
like points, and lines. The point reference is used to set the origin position and the line references
are used to set the axis system orientation. This is the same process in CATIA V5 also for creating
an axis system. The only difference between 3D Experience and CATIA V5 using VB.Net & VB
is that, in VB.Net, every variable should be defined. The codes are shown in the below figures.
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Figure 32: Axis Creation in Visual Studio for 3D Experience
Axis Transformation
In 3D Experience, Axis transformation is done by using the "AddNewAxisToAxis" statement,
which is used to transform any 2D & 3D elements from the reference axis to the target axis system.
Here, axis transformation works by creating a copy of the new element and transforms it onto the
target axis, while the original element is still on the reference axis system. So, after doing axis
transformation, 2 same elements can be seen on both the reference and target axis systems.
According to the requirement, to make sure that the axis of the body has transformed to the required
orientation after the ais transformation is completed, the original body will be hidden, so that the
copied body can be seen in the required orientation. Here the element to be axis transformed is
defined as a reference and this reference is added to the axis transformation statement as shown in
the Figure 33.
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Figure 33: Axis Transformation in Visual Studio for 3D Experience
Whereas in CATIA V5, the Axis transformation is done by transforming the original body onto
the target axis system. The automation process of axis transformation is the same in CATIA V5
also, but the difference here is that there is no need to write the code for hiding the elements. Here,
the element to be axis transformed is selected from its respective part family, and that part is made
as to the working object by using the statement "Inworkobject". The code for this is shown below
figure.
Figure 34: Axis Transformation in Visual Basics for CATIA V5
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The final obtained design assembly of the modular fixture’s platform is shown in Figure 35 &
Figure 36,
Figure 35: Design assembly of MFP in CATIA V5
Figure 36: Design assembly of MFP in 3D Experience
Inside the model tree, separate pillar sheets are imported as different sub-products under one main
product named V426. Inside each product, there are multiple parts respective to that sheet part.
Unlike the original Volvo fixtures, all the locators have individual risers and holders. The axis of
the holes is used to adjust for the orientation of the locators. The elements of modular fixtures like
clamps and locators are created separately in CAD with the correct fixing dimensions and
clearance. The fixturing components like clamps, locators, holders, cylinders, and pillars are
designed separately and used for assembly of the whole MFP using instantiation in the design
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automation process. These components can be assigned with the parameters through which their
size and shape can be modified easily. Parametric modeling requires design engineers to use
"design intent". This means that they have to think of the design as a real-world representation of
the object—changes can, or cannot be made, the same way changes would or wouldn't be made to
a real-world object. Parametric modeling, therefore, requires the designer to think and plan
considering every action.
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4.3. Robot Simulation:
In robot simulation of spot-welding operation, the application called “DTD” is used in CATIA V5
and the application called “RSS” is used in 3D Experience.
DTD is used for digital manufacturing process planning in CATIA V5. This application makes the
designer capable of programming, simulating, and validating mechanical devices ranging from
simple clamps to complex lift assist mechanisms such as robots. To eliminate interference and
achieve optimal cycle times, every device is individually programmed with tasks that are
sequenced and simulated. Designers can alter a mechanical device by adding, replacing, and
editing the existing parts or joint attributes. In DTD, robots for different purposes from different
companies exists in the robot library, which can be used according to the requirement.
RSS is used for digital manufacturing process planning in 3D Experience. This application is also
used for programming, simulating, and validating the different types of mechanical devices. The
difference is that robot spot simulation is only used for spot welding operation in 3D Experience,
whereas CATIA V5 can do all digital manufacturing operations using DTD. 3D Experience also
has an application that is used for doing all manufacturing operations called "Robot Simulation".
But only spot welding is made using the RSS application for its benefits. The comparison between
this application in both the software's is explained below.
The main interface difference between 3D Experience and CATIA V5 is already explained in the
above paragraphs. The Tabs that exist in RSS are Standard, Setup, Programming, Point Fastening,
Drill Fill, Analysis & Output, PPR Standard, selection mode, View, AR-VR, Tools, Touch. The
programming tab holds the command options for creating and teaching the robot task. Analysis &
Output tab holds the command options for creating spot profile and spot weld trajectory. Whereas
in DTD, the command options called tag groups, tag points and robot task support exist. This
difference is because RSS is the special application only used for the spot-welding operation. In
the robot simulation app, which is similar to DTD, similar command options such as tag groups,
tag points, etc.., exist, as it is used to make all kinds of manufacturing operations except spot
operation.
Figure 37: 3D Experience Action Bar in Robot Spot Simulation
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Figure 38: CATIA V5 Interface of Device Task Definition
As shown in the design automation flow chart in methodology, the difference between CATIA V5
and 3D Experience design automation process according to that flow chart is explained below.
4.3.1. Comparison of codes
Get Part
In 3D Experience, the get part document step is done using its working definition is
"PLMProductService". This working definition is used to open the entities concerning
VPMOccurence and VPMReference that exist in the active design model window in terms of PPR,
manufacturing cell, robot, resource, tools. This identifies the occurrence entity by its parent root
occurrence and reference entity by its parent occurrence from the model and then opens that
respective item entity from the 3D Experience collaborative database search. Unlike the "GetPart"
function explained above, "VPMOccurence" will select and open any entity by finding its parent
or child. The full form of VPM is virtual product management, which manages the product data in
the 3D Experience cloud database. The detailed code for this is shown in the below figure.
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Figure 39: Get Entity using VPMOccurence in Visual Studio for 3D Experience
Whereas in CATIAV5, as explained in the DA "GetPart" step, it is easy to call any part or product
entity directly by just setting the active document and call with the required item name and its type.
Though the entities here are in terms of PPR which are process list, product list, and resource list,
VB in automation considers entities as part and products only. So, it is the same process here in
RSS, get part document step, such as it is in DA get part document step.
Figure 40: Get Part in Visual Basics for CATIA V5
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Create robot spot trajectory
In 3D Experience, create robot spot trajectory step is done using a working definition called
"PointTrajectory" which also means spot-welding point trajectory. Spot welding trajectory is the
path followed by the spot welding positions which help the object (weld gun) with mass to move
under the action of given forces by a robot on the workpiece(B-pillar) as the function of time. This
SWT is the input to the robot task for doing the spot-welding manufacturing operation. The code
for this is shown below figure.
Figure 41: Spot Weld Trajectory in Visual Studio for 3D Experience
Whereas in CATIA V5, the working definition called "TagGroup" is used instead of robot spot
trajectory. Tag groups are the parents for tag points which show the path for the robot to move on
the workpiece for the spot-welding operation. The difference between SWT & tag groups is that
using tag groups the robot motions have to be created separately with operations, which is not
required using SWT. The code is shown below figure.
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Figure 42: Tag Group in Visual Basics for CATIA V5
Create robot task
In 3D Experience, create a robot task is done using the working definition called "ResourceTask",
which is used to create the robot motions and operations and store them inside it. Resource task
acts as the main source of output for spot welding simulation. Here, the resource task in connection
with the robot will be stored in an entity called "behaviors" in the model tree, which consists of all
inputs and outputs of the simulation.
Figure 43: Robot Task in Visual Studio for 3D Experience
Whereas in CATIA V5, the working definition called "RobotTask", is used which is similar to
"ResourceTask". This difference is only in the definitions but not in working. Robot task and
resource task both work for creating robot motions and spot-welding operations only. Here, robot
tasks will be stored inside the robot and can be accessed directly from robots.
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Figure 44: Robot Task in Visual Basics for CATIA V5
Create robot motions & spot-welding operations
In 3D Experience, creating robot motions and operations is done using the working definition
called "RobotMotionActivity", which is used to create the motion profile or path of the robot for
the spot-welding operation. This decided the robot's motion, how it moves and where it stops
according to tag point or spot welds. In RSS, as spot welding trajectories are used as inputs to
robot tasks, the code for the creation of robot motions is not necessary. They will be created
automatically when the operations are created. Operations are created using a working definition
called "PointOperation", which is used as a spot-welding operation for joining the car pillar sheets
together.
Figure 45: Spot operations in Visual Studio for 3D Experience
Whereas in CATIA V5, the definition called “RobotMotion”, is used to create motions by selecting
one tag point for every motion creation as the input in the loop. Here robot motions are required
unlike 3D Experience and the operations are not possible to create in VB automation but can be
copy-pasted in the loop with the manually created robot operations.
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Figure 46: Robot motions & operations in Visual Basics for CATIA V5
Teach task and run simulation
The next step in RS is the teaching task, which is required to modify the inputs of the robot tasks
such as tag groups or spot weld trajectories and robot motions. Then the simulation can be executed
by activating the robot task, and the time and frames rate for simulation can be given in the play
simulation options in both 3D Experience and CATIA V5. This can be clearly understood by
checking the figures below.
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Figure 47: Play Simulation in Visual Studio for 3D Experience
Figure 48: Play Simulation in Visual Basics for CATIA V5
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5. Discussion
5.1. Project Outcome
The fixturing technologies developed in this project, currently do not satisfy the industrial
expectations due to some complex fixture design platforms. Computer-aided fixture design and
knowledge-based engineering are integrated as solutions for this existing complex fixture design
process. The main requirement for designing is to restrain a workpiece by a fixture with locators(l)
and clamps(c) which have their tip in contact between the fixture element and workpiece. The
welding operation is performed on the workpiece (B-pillar), constrained by fixtures from
movements due to passive forces. The fixture locators and clamps should change their orientations
according to the position of the workpiece. The master locating points on the workpiece are chosen
to minimize the passive forces of the contacts due to machining and active clamping. Automated
computer-aided fixture design allows the user to define a feasible fixture configuration, including
locating methods and clamping mechanisms, and layout for a given workpiece. Therefore, the
design automation and automatic digital manufacturing on the modular fixture configuration which
are used to hold the B-pillar sheet must be done by utilizing the CAD software to solve the
problem. By doing this method, necessary differences are identifying between two Dassault
systems softwares and explained in the results.
As mentioned in the literature study, many researchers worked with different methods for the
development of fixtures in manufacturing industries. But, unlike them, our work includes the
complete automation of modular fixtures design assembly that can be reconfigured in required
orientations and, automation in digital manufacturing of spot-welding operation on car B-pillar
fixed to MFP. Ali Keyvani's work was mostly focused on the usage of Tecnomatix software for
the development of MFP, whereas Vukelic's main focus was on analyzing the stiffness of the
mounting frame type modular fixtures using FEM.
Uday. Farhan's works were more towards the development of modular fixtures for manufacturing
industries using CAD which seems much similar to this project. He used solid works in modular
fixtures design and assembly process by using multiple rules and reactions in API with connected
parameters which means it is the semi-automated design process. In this thesis, the design and
assembly of modular fixtures are done fully automated using two software and two scripting API.
Iker Erdem worked on finding the key to increase the efficiency of the flexible fixtures in
manufacturing industries by using four different design research methods. In his research question-
answers, he mentioned that accuracy and repeatability describe how correctly & repetitively a
workpiece can be located on a fixture’s platform. In this thesis, that problem is avoided by using
the 3-2-1 method to locate the workpiece to be fixed on the fixture’s platform. By using
instantiation and axis transformation methods in design automation, repeatability can be achieved
through reconfiguration of fixture elements.
In Erdem’s research, the final proposed design method offers two solutions for increasing the
efficiency of flexible fixtures in manufacturing industries by choosing between,
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1. Flexible fixtures with different fundamental features to detect fixturing solutions with high
efficiency.
2. The components of individual flexible fixtures to identify and replace the source of
inefficiency.
In this thesis, both are satisfied by using Design Automation for modular fixtures assembly,
through which different components of modular fixtures can be replaced according to their
requirement. The instantiation process is used multiple times, to instantiate one component onto
another to complete the full assembly of modular fixtures. This helps by increasing the ease in the
assembling and dissembling of modular fixtures platforms. Through this, the efficiency of modular
fixtures in manufacturing industries also increases.
After all these research works done on the development of flexible modular fixtures with
automation in CAD & CAM, there is a lot more to be done for the required modular fixtures
technology in manufacturing industries to make the production process more efficient with less
time consuming and low-cost investment. So, our focus in this project is research based on test
results on CAFD and CAFM using automation in CATIA V5 & 3D Experience environments
connected to excel & visual studio applications. The main objective is the comparative study of
CATIA V5 and 3D Experience through the development of a modular fixture’s platform. This is
the first comparative study on 3D Experience after its development happened, which was not done
before. Design automation and robot simulation are methods used for comparison, and modular
fixtures are the main topic chosen for the development using these methods.
5.2. Answering The Research Question
RQ1: What is the difference between CATIAV5, and 3D experience? Explain with advantages
and disadvantages of the process in each application.
There are two main differences between CATIA V5 and 3D Experience which make them
antithetical, are their graphical user interfaces and the data storage feasibility. There is an extensive
development in 3D Experience, model interface, and visualization and it also came up with the
cloud database storage which is one of the most demanded developments in the present CAD
business sectors.
Through this database, the efficiency of designing increases, and the time consumption in the CAD
process decreases as the access can be given to different persons to the required extents by the
respective collaborative space owners & leaders.
Differences:
3D Experience CATIA V5
In axis transformation, copy of the original
body will be created and transferred to the
target axis.
Axis transformation works by transferring the
original body from reference to the target axis.
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All the power-copy elements will be stored
inside the geometrical set and for this, the
body should have the volume extrude but not
solid extrude.
Power-copy file after instantiation can be
stored using both part body and geometrical
set.
Any model saved in a specific module cannot
be opened in another application. In some
cases, while working on a certain application,
the other models active in 3D Space, will also
automatically be saved under that application,
which cannot be changed in the future.
Any model, part and product can be opened in
any specific module such as part design,
Generative shape design, device task
definition.
It segregates modules with respect to their
working functions and accommodates
respective commanding options. So, all the
options are perfectly aligned and can be
easily found in the action bar with the bigger
icons and visible names.
It accommodates multiple commanding
options used for doing different operations in
a single module, due to which few options are
hidden in the action bar and are difficult to
find sometimes.
If a command is searched with some syntax
that does not exist, it shows few suggestions
which match near to that.
If a command is searched with some syntax
that does not exists, it shows error msg “Syntax
Error”.
Software crashes while working on
complicated designing, and high-quality
renderings
Not observed any software crashes while
working.
Creation of a new product using design
automation is not possible due to the
limitations of the software license
No license issues found.
Working with behaviors is complicated in
robot simulation, as it consists of control
attributes, inputs, outputs, and tasks of the
simulation.
There are no behaviors, and the connections
between model entities are direct which
makes it easier.
Virtual Reality (VR) and Augment Reality
(AR) functions exists.
Virtual Reality (VR) and Augment Reality
(AR) functions don’t exist.
High resolution rendering options like
"stellar" are available through which,
materials and styling can be added in
different tones and effects at different
positions required for the model.
Stellar doesn’t exist.
In generative shape design module, new
function called tool sweep is developed,
which allows creating 3D shape by moving a
symmetrical 2D profile along a specified path
in 3D area
Tool Sweep doesn’t exist.
In robot spot simulation, the spot profile will
be created through which the weld gun
No such option.
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parameters such as dimensions, tip clearance,
and arm tolerances can also be modified,
which makes the spot-welding process more
efficient.
In robot spot simulations, robot motions are
created automatically with the operations
using spot-welding trajectories.
In device task definition, robot motion and
operations are created separately.
Kinematics of a robot can be adjusted to
avoid singularities by modifying robot joint
values in automation.
Modification of kinematics is not possible in
automation.
RQ2: How can automation of Design and Digital manufacturing be achieved?
The automation in design and digital manufacturing is achieved by using instantiation and axis
transformation for the design and assembly of the modular fixture’s platform and by creating the
robot tasks using the robot for spot welding operation on a component fixed with modular fixtures.
These processes are done by using different applications in CATIA V5 and 3D Experiences such
as Generative shape design, device task definition, robot spot simulation, plant layout design CAD
applications, and VB & VB.net programming languages.
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6. Conclusion
3D Experience has the unique ability to connect the employees of various departments in the
company working on the design development of different projects together.
Performance, support, online training, and implementation are very efficient in 3D Experience
compared to CATIA V5. For efficient usage of the 3D Experience software, a powerful processor
and the highest quality of graphics are required. Due to this requirement of advanced hardware
and software built-in computers, 3D Experience is a cost-ineffective program. It also needs high
maintenance, by frequently updating the graphics and performance drivers connected with the
software. Hence, availability, usability, and reliability are better in CATIA V5 than 3D Experience.
Creation of manufacturing operations and controlling the robot kinematics are not possible in
CATIA V5 automation, which is one of the major drawbacks of production planning.
Developments in the automation of digital manufacturing in CATIA V5 are required.
As 3DX is the upgraded version of CATIA, it is built with modern contemporary features in its
applications. 3D Experience is developed as the house of all the CAD, CAM, CAE, and other
applications to develop products related to various industrial sectors such as mechanical, electrical,
and civil, etc. This evolution of the 3D Experience platform helps many business industries, by
minimizing the investments in purchasing different software applications for doing different tasks
from different companies. 3D Experience re-created its graphical assets for the high-resolution
screens that are available today through which visual clutter is avoided or reduced.
6.1. Future Work
The following few ideas that are proposed for the future research purpose,
• The elastic deformation of the workpiece due to the clamping and welding forces can be
minimized in fixture platforms by using multi-disciplinary optimization. This optimization result helps to create the optimum fixture layout which shows minimum deformation.
• The advanced computer-aided fixture design can be enhanced using the visual reality
feature in 3D Experience. VR is one of the new developments in CAD software. VR systems can simulate various physical behaviors of fixture elements according to physics laws. Through this, entire fixture design automation can be completed in the virtual environment as if in the real physical world.
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Appendix
Appendix 1:
1.1 Catia V5 Design Automation Codes using Visual Basics The codes used to do design automation of modular fixtures platform in CATIA V5 are shown
below. The commented part of script is also correct and used in different conditions & situations
according to user’s requirement. So, that part is not removed from the codes as it could be useful
for any designer who works on the similar concepts.
Generation of Modular Fixtures
VB Script for Axis System creation: The first module in the VBA is executed to create the axis
systems as the references for fixturing elements instantiation process.
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In this script the axis systems were created by taking point references from hybrid body named
“Master_Locating_Systems” in the part document “COMP_31_31860092-01. CATPart”. This is
done using 3 different loops as the naming order of references are irregular. So, different “If
Condition” are used in all the 3 “For loops”. In loop, point reference “Y” & “i” are equaled to
“CAM”.
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VB Script for fixturing elements Instantiation: This module is executed for instantiating clamps,
holders & pillars in connection to one another to make complete modular fixtures platform.
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Now, holder instantiation is done by using the axis references that are created on clamps. These
holders are supporting the clamps which are holding B-pillar workpiece. The code for that can be
seen below.
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Here the pillar instantiation is done with respect to holders. Pillars were instantiated by using
references that were created on holders in the previous operation. These pillars are supporting the
holders on the manufacturing layout of modular fixtures with connection to holders.
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VB Script for Pin/locator instantiation: This module is executed for instantiating the pins on the
correct positions of the B-pillar sheet part by using point references. After the pin get
instantiated, the references will be created in the pins to use them as references for its holders’
instantiation.
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Visual Basics script for Pin/locator-holders Instantiation: Pin-holders instantiation codes can be
seen below. These holders are used to support the pins that are connected to the workpiece on
modular fixtures platform. The pins are concentric to the surface of the workpiece fixed in the
hole with the locating point reference.
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1.2 3D Experience Automation Codes using Visual Studio The codes used to do design automation of modular fixtures platform in 3D Experience are
shown below.
Generation of Modular Fixtures
VB.Net Script for Public Not Inheritable Class: The first-class script in the Visual Studio is used
to lead the modules that will be written as a parent and is named as “This Application”. This
class is marked as not Inheritable to prevent the accidental inheritance in the different modules to
be executed. The purpose of this class is to provide some implementation that can be used within
that class only.
The above-mentioned code is the main class with the help of which the main module of different
scripts works. The script for axis systems creation on B-pillar workpiece in 3D Experience
CATIA as the references for instantiation can be seen in below. The axis systems were created
by using the reference points from hybrid body named “Master_Locating_System”.
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VB.Net Script for Axis System creation: The first module in the Visual Studio is executed to
create the axis systems as the references for fixturing elements instantiation process.
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VB.Net script for fixturing element clamp Instantiation: The clamps were instantiated by using
the reference axis systems that were created using the point references in the previous operation.
The clamps are used to hold the workpiece on modular fixtures platform to avoid disturbances
while doing operations like welding, machining, assembling, etc. After the instantiation of
clamps, the new axis system was created on the clamps to do axis to axis transformation to
position the clamp in the required orientation.
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VB.Net Script for Holder Instantiation: The holders were instantiated by using the reference axis
systems that were created on the clamps in the previous operation. The holders are used to
support the clamps that are connected to workpiece on modular fixtures platform.
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VB.Net script for Pillar Instantiation: The pillars were instantiated by using the reference axis
systems that were created on the holders in the previous operation. The pillars are used to
support the other elements assembled to the modular fixture’s platform. Pillars serves as the
main supporting elements of the platform connected to the manufacturing layout of the MFP.
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The above-mentioned codes explain the design automation procedure of building modular
fixtures platform that is used to hold the Volo car A, B, C-pillar workpieces for assembling them
together using spot welding operation.
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Form button code in VB.Net: This calls and executed all the modules at once by just clicking on
the “Instantiation” button.
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Appendix 2:
2.1 CATIA V5 Robot Simulation Automation Codes using Visual
Basics
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2.2 3D Experience Robot Simulation Automation Codes using VB.Net
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