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A HYBRID SYSTEM COMBINING RAPID
PROTOTYPING AND CNC MACHINING OPERATION
BY
A N M AMANULLAH TOMAL
A thesis submitted in fulfilment of the requirement for the
degree of Master of Science (Mechatronics Engineering)
Kulliyyah of Engineering
International Islamic University Malaysia
FEBRUARY 2018
ii
ABSTRACT
At present, two important processes, namely CNC (Computer Numerical
Control) machining and rapid prototyping (RP) are being used to create
prototypes and functional products. CNC machining (subtractive method) is
relatively more precise and accurate, but it is tough to create stuffs with complex
features. RP (additive method), by contrast, is able to form parts with
sophisticated features, that consents materials to be utilized more efficiently.
Combining both subtractive and additive process on a single platform has
significant advantages. However, there are two important aspects need to be
taken into consideration for this process hybridization. First aspect is the
integration of two different control systems for two processes and second aspect
is maximizing workpiece alignment accuracy during the changeover step. This
research attempts to assimilate both of these processes and propose a new design
of hybrid machine with the purpose of overcoming the drawbacks related with
different control panel and misalignment issues. Fused deposition modeling
(FDM) is considered as the RP process in this study. A new innovative design
for hybrid system, consisting of CNC machining and FDM, was proposed in this
study. One of the aspects of the design consist of installing the CNC cutting
spindle and the heat extruder of FDM on a rotary stage and using the IR sensors
which makes the mechanism simpler and overcomes the problem of
misalignment. The rotary stage has also given the advantage of using the 3-axis
machine as a 4-axis machine. The other feature of this research was the single
control panel for both CNC machining and FDM operation. The case studies
undertaken in this research demonstrated that the proposed hybrid system can
conduct three-axis machining on a completed FDM part or trim the surface of
the parts with two different layers fabricated by FDM to achieve more accurate
dimensions or better surface finish. Several objects were produced with different
layer thickness for example 0.1 mm, 0.15 mm and 0.2 mm. About 99.87%
accurate dimension was achieved after CNC grinding operation. Finally,
dimensional accuracy was improved by 92% when the FDM part is compared
with the final part after grinding operation. At the same time average surface
roughness (Ra) was reduced by 90%. It was also observed that layer thickness
plays a role on the dimensional accuracy and best accuracy is achieved with the
minimum layer thickness (0.1 mm).
.
iii
خلاصة البحثABSTRACT IN ARABIC
CNC المنتجات هما و النماذج لصنع يستخدمان مهمتان عمليتان ، في الوقت الحاضر Machining and Rapid prototyping (RP) . العمليةCNC Machining ة هي عملي
قطع باستخدام الآلة بحيث يكون القطع أو الحفر دقيق ومتقن. لكن هناك صعوبة بصنع النماذج المعقدة بهذه العملية. هي عملية إضافة قادرة على صنع النماذج الأكثر تعقيداً بكفاءة ودقة. بجمع العمليتين على منصة RPفي المقابل عملية
ومع ذلك، هناك جانبان مهمان يجب علينا أخذهما بعين الاعتبار من أجل واحدة نحصل على إيجابيات كلتا العمليتين.عملية الدمج أو التهجين. الأول هو دمج اثنين من أنظمة التحكم المختلفة للعمليتين والثاني هو زيادة دقة العمل أو الحفر
تصميم آلة جديدة هجينة للتغلب خلال خطوة التحول. هذا البحث يدرس التخفيف أو الحد من هاتين العمليتين واقتراح Fused في هذا البحث هي RPعملية على العيوب المتعلقة بالتحكم بالعملية وموضوع عدم الاتساق.
Deposition Modeling (FDM) تصميم نظام هجين يحتوي على .CNC Machining and
FDM برمجة وتنصيب هي ما سوف تناقشه هذه الدراسة. واحدة من الجوانب في التصميم هيCNC Machine التي تجعل العملية أبسط وتحل مشكلة عدم IRفي مرحلة الدوران واستخدام المستشعر FDMوجعلها تعمل مع
الاتساق. من ايجابيات الدوران هو جعل الآلة ثلاثية المحاور تعمل كأنها آلة رباعية المحاور. وهناك ميزة مبتكرة أخرى ألا هذه الدراسة تبحث في النظام الهجين الذي يعمل .CNC and FDMللعمليتين كم واحدةوهي استخدام لوحة تح
أو جعلها تقطع سطح النماذج مع اختلاف في سمك الطبقة FDMجعلها تعمل على نموذج المحاور و على آلة ثلاثيةف في سمك الطبقة العديد من النماذج قد انتجت قد انتجت مع اختلاFDMالمقطعة أو السطح باستخدام عملية
CNCبعد عملية 99.87. نسبة دقة الأبعاد قد كانت% 0.1mm ,0.15 mm, 0.2 mm،على سبيل المثال
Grinding عند استخدام 92%. أخيراَ ،دقة الأبعاد قد زادت بنسبةFDM بعد عمليةCNC Grinding .حظ أن سمك الطبقةالمقطعة يلعب .لقد كان من الملا90 %قد خفض بنسبة Raبنفس الوقت متوسط خشونة السطح
دوراً مهماً بتأثيره على دقة الأبعاد وأن أفضل دقة يمكن الحصول عليها هوعند استخدام أقل سمك . 0.1mmللطبقةالمقطعة
iv
APPROVAL PAGE
I certify that I have supervised and read this study and that in my opinion, it conforms
to acceptable standards of scholarly presentation and is fully adequate, in scope and
quality, as a thesis for the degree of Master of Science (Mechatronics Engineering).
…………………………………..
Tanveer Saleh
Supervisor
…………………………………..
Md. Raisuddin Khan
Co-Supervisor
I certify that I have read this study and that in my opinion it conforms to acceptable
standards of scholarly presentation and is fully adequate, in scope and quality, as a thesis
for the degree of Master of Science (Mechatronics Engineering).
…………………………………..
Syamsul Bahrin Abdul Hamid
Internal Examiner
…………………………………..
Prof. Dr. Imtiaz Ahmed
Chowdhury
External Examiner
This thesis was submitted to the Department of Mechatronics Engineering and is
accepted as a fulfilment of the requirement for the degree of Master of Science
(Mechatronics Engineering).
…………………………………..
Syamsul Bahrin Abdul Hamid
Head, Department of
Mechatronics Engineering
This thesis was submitted to the Kulliyyah of Engineering and is accepted as a
fulfilment of the requirement for the degree of Master of Science (Mechatronics
Engineering).
…………………………………..
Erry Yulian Triblas Adesta
Dean, Kulliyyah of Engineering
v
DECLARATION
I hereby declare that this dissertation is the result of my own investigations, except
where otherwise stated. I also declare that it has not been previously or concurrently
Submitted as a whole for any other degrees at IIUM or other institutions.
A N M Amanullah Tomal
Signature ........................................................... Date .........................................
vi
COPYRIGHT PAGE
INTERNATIONAL ISLAMIC UNIVERSITY MALAYSIA
DECLARATION OF COPYRIGHT AND AFFIRMATION OF
FAIR USE OF UNPUBLISHED RESEARCH
A HYBRID SYSTEM COMBINING RAPID PROTOTYPING
AND CNC MACHINING OPERATION
I declare that the copyright holders of this dissertation are jointly owned by the
student and IIUM.
Copyright © 2018 A N M Amanullah Tomal and International Islamic University Malaysia. All
rights reserved.
No part of this unpublished research may be reproduced, stored in a retrieval system,
or transmitted, in any form or by any means, electronic, mechanical, photocopying,
recording or otherwise without prior written permission of the copyright holder
except as provided below
1. Any material contained in or derived from this unpublished research
may be used by others in their writing with due acknowledgement.
2. IIUM or its library will have the right to make and transmit copies
(print or electronic) for institutional and academic purposes.
3. The IIUM library will have the right to make, store in a retrieved
system and supply copies of this unpublished research if requested by
other universities and research libraries.
By signing this form, I acknowledged that I have read and understand the IIUM
Intellectual Property Right and Commercialization policy.
Affirmed by A N M Amanullah Tomal
……..…………………….. ………………………..
Signature Date
vii
ACKNOWLEDGEMENTS
First of all, Alhumdulillah and all praise to ALLAH (S.W.T), the Most Beneficial and
Most Merciful, to give me the ability and knowledge to accomplish my research work
successfully. Then, I would like to thank my supervisor Dr.Tanveer Saleh for his
dedicated guidance, suggestion, motivation and valuable support which has directed me
the way to develop my research skills and knowledge as well. He has not only guided
me as a supervisor but also I want to mention him as a guardian. I also like to thank my
co-supervisor Dr.Md. Raisuddin Khan for his endless encouragement and support to my
research work. I would like to thank Brother Taufiq and sister Nazreen for their help to
develop the three-axis machine. I would like to extend my gratitude to others who also
have helped me in using research instrument for my experiments as the technicians of
the Engineering Laboratories in IIUM.
I am also grateful to Mechatronics Engineering Department and Kulliyyah of
engineering for giving me the research facilities.
I would like to give special thanks to my wife for her guidance and support for
my study. Finally, I would like to mention my parents who always keep me in their
prayers to almighty “ALLAH” for every single bit of my success.
viii
TABLE OF CONTENTS
Abstract .......................................................................................................................... ii
Abstract in Arabic ......................................................................................................... iii
Approval page ............................................................................................................... iv
Declaration ..................................................................................................................... v
Copyright ...................................................................................................................... vi
Acknowledgements ...................................................................................................... vii
Table of contents ......................................................................................................... viii
List of tables ................................................................................................................... x
List of figures ................................................................................................................ xi
List of Abbreviations ................................................................................................. xiv
CHAPTER ONE : INTRODUCTION ....................................................................... 1
1.1 Background ............................................................................................. 1
1.2 Problem statement and its significance .................................................. 3
1.3 Research Objectives: .............................................................................. 3
1.4 Research Methodology: .......................................................................... 4
1.4.1 Methodology for Objective 1 .................................................... 4
1.4.2 Methodology for Objective 2 .................................................... 6
1.4.3 Methodology for Objective 3 .................................................... 6
1.5 Research Scope ....................................................................................... 8 1.6 Thesis Organization ................................................................................ 8
CHAPTER TWO : LITERATURE REVIEW ........................................................ 11
2.1 Introduction .......................................................................................... 11
2.2 Additive manufacturing (AM) process ................................................. 12
2.2.1 Different types of AM Processes ............................................. 13
2.2.1.1 Liquid Based AM systems ........................................... 14
2.2.2.2 Solid‐based AM systems ............................................ 16
2.2.2.3 Powder‐based AM systems ........................................ 18
2.2.2 Post Processing Techniques Of Additively Manufactured
Parts ......................................................................................... 20
2.3 Subtractive processes .......................................................................... 22
2.4 Hybrid additive and subtractive manufacturing processes ................... 24
2.4.1. Laser cladding and mechanical machining ............................. 25
2.4.2. Shape deposition manufacturing (SDM) and mechanical
machining ............................................................................... 29
2.4.3. Arc welding and mechanical machining ................................ 30
2.4.4. Injection moulding and milling .............................................. 33
2.4.5. Electroforming and polishing ................................................. 33
2.4.6. FDM and machining: .............................................................. 34
2.5 Chapter Summary: ................................................................................ 35
ix
CHAPTER THREE: DESIGN AND DEVELOPMENT OF THE NEW
HYBRID MACHINING SYSTEM .......................................................................... 37
3.1 Introduction .......................................................................................... 37
3.2 Development of the Hybrid Machine ................................................... 37
3.2.1 Mechanical Structure of the System ........................................ 37
3.2.1.1 Analysis of Power and Torque of Spindle ................... 38
3.2.1.2 Driving System of the Hybrid System ......................... 39
3.2.1.3 Selection of Rotary stage ............................................ 44
3.2.1.4 Selection of Infrared Sensors ....................................... 45
3.2.1.5 Implementation of CNC spindle and FDM
extruder ........................................................................ 46
3.3 Development of the Control System .................................................... 47
3.3.1 Control System for Three axes Movement and CNC
Machining Operation ............................................................... 49
3.3.1.1 Callibration of Target Position for Servo
Motors .......................................................................... 49
3.3.1.2 GUI for CNC machining operation: ............................ 50
3.3.2 Control System of 4th axis and FDM Operation: ..................... 52
3.3.2.1 Callibration of speed for Stepper Motor: ..................... 52
3.3.2.2 GUI for FDM operation:.............................................. 53
3.3.2.3 Temperature control of heater and heat bed ................ 54
3.3.3 Control System for Alignment: ............................................... 56
3.4 Chapter Summary ................................................................................. 57
CHAPTER FOUR: RESULTS AND DISCUSSION .............................................. 59
4.1 Introduction .......................................................................................... 59
4.2 Dimensional Accuracy Test ................................................................. 60
4.3 Surface roughness study ....................................................................... 66
4.4 Chapter Summary ................................................................................. 72
CHAPTER FIVE : CONCLUSION AND RECOMMENDATIONS ................... 73
5.1 Conclusion ............................................................................................ 73
5.2 Recommendations ................................................................................ 75
REFERENCES ........................................................................................................... 76
PUBLICATIONS ....................................................................................................... 82
APPENDIX A ............................................................................................................. 83
x
LIST OF TABLES
Table No. Page No.
2.1 Different Post Processing Techniques 22
3.1 Parts for CNC Machining 46
4.1 Measured Dimensions (mm) for Different Layer Thickness 64
4.2 Roughness Parameters in m 68
4.3 Material Ratio Parameters 68
xi
LIST OF FIGURES
Table No. Page No.
1.1 Involvement of various processes in metal parts production (Levy et
al 2003) 2
1.2 Proposed design of the with CNC spindle 6
1.3 Proposed design of the with CNC spindle 6
1.4 The complete research plan of methodology 7
2.1 The eight stages of the RP process 13
2.2 Classification of Additivie Manufacturing Processes 14
2.3 Illustration of SLA 15
2.4 Ice parts built by the RFP process (Guo & Leu, 2013) 16
2.5 Illustration of FDM process 17
2.6 Position of RP and CNC in terms of their characteristics 25
2.7 Design of the hybrid maching system with selective laser cladding and
milling 27
2.8 Hybrid machine is presented with additive head permanently
mounted adjacent to the machining spindle (Kerschbaumer & Ernst,
2004) 28
2.9 Shape deposition manufacturing (SDM) cycle with addition and
removal of part and support materials (Lanzetta and Cutkosky,
2008)List of Actual Use of Digital Technologies Items 29
2.10 Hybrid Machining System with 3D welding and milling
machine(Song & Park, 2006) 30
2.11 Developed Hybrid machine with welding torch and milling
cutter(Akula & Karunakaran, 2006) 31
2.12 Example of a mould core using hybrid machine combining additive
(GMAW) and subtractive (CNC machining)(Karunakaran et al.,
2009) 32
2.13 Integrating changes in design of a part using reconfigurable tooling
system (Kelkar&Koc,2008) 33
xii
2.14 Hybrid System of Electroforming Process with Polishing of Hard
Particles (Zhu et al., 2006) 34
2.15 Hybrid Machine with FDM and 5 axis Machining 35
3.1 Different Forces During Machining Operation 40
3.2 Three axes machine 44
3.3 When the object (CNC spindle or FDM extruder) is (a) in aligned
position; (b) in misaligned position 45
3.4 Three axis machine with rotary stage and IR sensors 46
3.5 Three axis machine with CNC Spindle 47
3.6 Total control Structure of the Hybrid System 48
3.7 GUI of the Hybrid System 49
3.8 Target position calibration for servo motors 50
3.9 GUI for CNC Machining Operation 51
3.10 Three axis Movement for IIUM Pattern 52
3.11 Velocity Calibration for Stepper Motor mm/s to RPM 53
3.12 GUI for FDM Operation 54
3.13 Temperature Control for Heater and Heat Bed 56
3.14 The difference of reflected IR signals as analog voltage when the
object is in (a) aligned and (b) mis-aligned position 57
4.1 Total experimental procedure 59
4.2 Production of the FDM part 60
4.3 CNC Grinding operation on produced part 61
4.4 Surface of the FDM part (without machining) with layer thickness (a)
0.1mm (b) 0.15 mm and (c) 0.2 mm (with gap showing insight) 62
4.5 Surface of the FDM part (with machining) with layer thickness (a)
0.1mm (b) 0.15 mm and (c) 0.2 mm 63
4.6 Comparison of dimensions in (a) length ,(b) width, and (c) height
between targeted and final parts 65
4.7 Experimental Setup for Surface Roughness Test 67
xiii
4.8 Comparison of surface profile of the parts with 0.1 layer thickness 70
4.9 Comparison of surface profile of the parts with 0.15 layer thickness 70
4.10 Comparison of surface profile of the parts with 0.2 layer thickness 71
4.11 Average Roughness values vs Layer Thickness of created parts with
and without machining 72
xiv
LIST OF ABBREVIATIONS
ABS Acrylonitrile Butadiene Styrene
AM Additive Manufacturing
3DP 3D Printing
LM Layered Manufacturing
LOM Laminated Object Manufacturing
CNC Computer Numerical Control
DED Directed Energy Deposition
PBF Powder Bed Fusion
FDM Fused Deposition Modelling
IR Infrared
LENS Laser Engineering Net Shaping
PLA Polylactic Acid
RP Rapid Prototyping
SEM Scanning Electron Microscope
SI Solid Imaging
SLC Selective Laser Cladding
SLS Selective Laser Sintering
STL STereoLithography
i.e (id est) that is
1
CHAPTER ONE
INTRODUCTION
1.1 BACKGROUND
The objectives of manufacturing systems are more powerful now because of over-all
competition in the development of product. Owing to spread the market rapidly,
products that are commonly used to produce prototypes, need to be manufactured within
scheduled time (Koren, 2010).Therefore, this development has appealed the attention
of technology developers to bring change in the methods of manufacturing that are
employed in producing prototypes. In the 1980s, RP- Rapid Prototyping technologies
were introduced and were used to produce prototypes quickly with an automation
process. RP is also known as ‘Layered Manufacturing’ (LM) and ‘Additive
Manufacturing’ (AM). Additive mechanism which implies to build the part by
combining layers of material (solid sheet, powder or liquid) until the whole product is
produced (Wohlers, 2000). This additive manufacturing technology has drawn
noteworthy interest due to its capability to overcome many drawbacks of traditional
manufacturing techniques. Its ability to form almost any geometric feature or shape is
a great advantage of AM (Hanser Gebhardt, 2003). RP technologies was introduced to
assist the development of new product specially for evaluation processes and analysis.
At early stages of product development, RP allows design changes and confirms
product’s validity before entering full scale production. With the time being RP
technologies have advanced and their scope has been extended to create finished parts.
Several techniques have been developed to establish RP technology as one of the most
2
reliable manufacturing methods. More developments have invented some advanced
techniques which are able to process metallic materials as well as to produce polymeric
products.
However, this technology is still besieged with several limitations which restrict its
abilities. Though this manufacturing technology is able to process metallic materials,
may not be capable of solving several important issues including surface roughness,
dimensional accuracy and final part properties (Campbell, Bourell, & Gibson, 2012;
Wong & Hernandez, 2012). Figure 1.1 represents the qualitative assessment of different
processes that are able to produce metal parts.
Figure 1.1 Involvement of various processes in metal parts production (Levy et al
2003)
According to Levy, Schindel, and Kruth (2003) only two processes are able to fabricate
metal parts directly. The rest of the processes can be considered as indirect processes as
they use different methods like as dies and moulds to createthe finished parts.
3
As the limitations of RP processes are still unsolved, other methods need to be
considered to solve the issues such as cutting operations. However, there is a limitation
in terms of part complexity despite the capability to handle low to medium production
quantities. This method of manufacturing is categorized under subtractive
manufacturing processes.
1.2 PROBLEM STATEMENT AND ITS SIGNIFICANCE
Both additive and subtractive approaches are important aspects of today’s prototyping
industry. Conventional CNC machining is a subtractive process. Subtractive processes,
as the name implies, create objects by removing unwanted material from a large block
or sheeting the form of chips. On the other hand, FDM is an additive process. It can’t
meet the need of subtractive approaches. In RP process though fast, easy of fabrication
and process automation is obtained at the same time accuracy, good surface finish are
not obtained which is possible in CNC machining. So the combination of FDM and
conventional CNC machining will accumulate the advantages of the bost operation into
a single work station. One system has been developed recently that is the combination
of FDM and five-axis machining. But in this system stepper motors were used which
creates a problem with less accuracy. Another remark is that in that system FDM
extruder was installed on the opposite end of the cutter spindle that is a bulky
mechanism. So, in this research, we will try to achieve better dimensional accuracy of
the finished part with compact mechanism.
1.3 RESEARCH OBJECTIVES:
This project presents in detail a hybrid system combining FDM and CNC machining
operation. The objectives of the project are as below:
4
1. To develop the mechanical system of the hybrid system.
2. To design and implement the graphical user interface based control system
for the hybrid system.
3. To evaluate the performance of the system in terms of surface roughness
and product accuracy by comparing with previous works.
1.4 RESEARCH METHODOLOGY:
This research has been carried out mainly based on experimental design, simulation and
control system implementation of the developed system. The following section
describes methodology for each objective of this proposed project.
1.4.1 Methodology for Objective 1:
The main structure of the machine was pre built with 3 servo motors for 3 axis. For that
purpose, at first the properties of the motors were justified to confirm its ability to
withstand with our newly developed hybrid system. For maintaining the alignment
during changeover process, a rotary stage and two IR sensors wrer used. In front of the
rotary sensor, there is an attachment where the CNC spindle and FDM heat extruder
was attached respectively just parallel to the Rotary stage. An L bracket was fabricated
to hold the FDM heat extruder. The IR sensors were attached to another attachment that
is perpendicular to the rotary stage. The sensors were used to omit the problems of
misalignment during exchanging the equipment of CNC milling and FDM process.
Figure 1.2 and figure 1.3 shows the proposed 3D figure of the hybrid system with CNC
spindle and heat extruder respectively.
5
Figure 1.2 Proposed design of the system with CNC spindle
Figure 1.3 Proposed design of the system with heat extruder
6
1.4.2 Methodology for Objective 2:
The whole control system for the machine was developed using separate controller and
circuitry to handle the CNC machining and FDM process. For our research purpose, we
have used LabVIEW 2014 to create the Graphical User Interface (GUI) for the newly
developed system. For controlling the whole process we have used NI PCI-7344, UMI-
7764. To perform the FDM operation, at first, we needed to draw the 3D figure of the
desired object. As most of the RP processes use the CAD file in STL (stereolithography)
format (Fadel & Kirschman, 1996), the 3D figure was converted into STL format .To
do these operations we used SolidWorks 2014. After that we sliced the CAD file into
layers with Slice3R software and we got the G codes for the FDM operation. Finally we
did the FDM operation. During the changeover process we controlled the signals
coming from the IR sensors to eliminate the misalignment issue. For this issue we have
used the NI DAQ USB 6211. The analog signals were coming from the IR sensors and
in the GUI it was represented as voltage. After that, we adjusted the position of the CNC
spindle by rotating the rotary stage according to the signal information from the sensors.
When the misalignment issue was eliminated we started the CNC grinding operation.
1.4.3 Methodology for Objective 3:
To investigate the performance of the machine the dimensional accuracy, surface
roughness and effect of layer thickness on the produced parts were studied. We have
used PLA (Polylactic Acid) material to produce several cubic parts with different layer
thickness. After doing the FDM operation, we replaced the FDM heat extruder with
CNC spindle with grinding stone. Figure 1.4 describes the process of methodology flow
for objectives of the research work.
7
Figure 1.4 The complete research plan of methodology
Mechanical Design of the
Machine
Development of the System
Development of the Control
Panel
Evaluation of the Performance
of the hybrid system
FDM operation and CNC
machining
Thesis writing
Desired
Performance
achieved??
Literature Review
Start
Stop
Yes
No
8
1.5 RESEARCH SCOPE
This research represents the development of a new hybrid system integrating two
processes namely CNC machining and FDM operation. We have developed the system
with simple mechanism with compared to other existing systems. The alignment issue
during the changeover process was eliminated by using Rotary stage and IR sensors.
The single control panel for the whole system was also a great achievement. The
technique requires a set of process parameters for experimental verification to achieve
the best parameter for the sensor fabrication. Primarily, the justification of the selection
of different motors investigation was carried out. Consequently, several cubic parts with
different layer thickness were produced to assess the system performance. Next,
dimensions were measured to test the dimensional accuracy of the both produced parts
with and without machining. Thereafter, the produced parts were investigated in SEM
so that we could get better idea about the surface finishing before machining and after
machining. Finally, the effect of layer thickness on thermoplastic parts was described.
1.6 THESIS ORGANIZATION
The thesis has been organized in 5 chapters which have highlighted the total research
work in detail. The 5 chapters are described briefly as below.
Chapter 1: As described in the previous sections, this chapter provides a brief
insight into CNC machining and RP technology along with the importance of hybrid
manufacturing system combining these two operation into a single workstation. It also
highlighted the developments that enable the RP process to manufacture finished
products. The last section highlights the research scope of this study technology.
9
Chapter 2: The literature review starts with introducing the Additive
Manufacturing Technologies along with its classifications and its usage in different
sectors. After that, the existing post processing techniques of additively manufactured
parts are described in briefly. Several processes are also described based on subtractive
processes. Next, a comparison is shown between CNC machining and additive
manufacturing processes. Advantages and limitations of each process are described
specially to fortify the argument for implementing RM applications and CNC
machining. Finally, several sections cover the developments that have been carried out
in hybrid manufacturing systems combining CNC machining and RP technology.
Chapter 3: The design and development of the whole hybrid system is
described in this chapter. Firstly, the mechanism of the total mechanical structure of the
hybrid system is described. After that, the justification of the existing servo motors to
withstand with the new system is validated. Later on, the mechanism behind using the
IR sensors is described. Along with these sections, the selection of several parts such as
rotary stage, IR sensors, is also described. Next, the whole control system is described
along with all sub control panels for different operations involved in the hybrid system
such as: jog and home operation, CNC machining operation, FDM operation, and
alignment operation.
Chapter 4: Performance of the newly developed hybrid manufacturing system
is evaluated in this chapter by producing several cubic parts with different layer
thickness. Firstly, the dimensional accuracy test is described showing the differences
of different layer thickness for both machined and un-machined parts. Secondly, the
roughness study is highlighted elaborately. In which, the comparative study of the
surface profile of each parts is described. During the production of the cubic parts and
10
CNC machining on them several problems raised. The problems are also highlighted in
this chapter with providing the possible actions to resolve them.
Chapter 5: The whole work discussed in this thesis is summarized in this
chapter. The findings of the previous studies related to hybrid manufacturing system are
highlighted. Furthermore, the shortcomings of this research work is highlighted and
recommendations are also included to give proper direction for future works that will
further improve this hybrid manufacturing system.