Pin type clamping

8/7/2019 Pin type clamping

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Afzeri International Islamic University Malaysia

[email protected]

A.G. E SutjiptoInternational Islamic University Malaysia

[email protected]

Riza Muhida International Islamic University Malaysia

[email protected]

Atiah A.S

International Islamic University Malaysia

[email protected]

AbstractCurrent machining shop floors, which are

characterized by large variety of products in small

batch sizes, require dynamic access and real-time

monitoring capabilities that are responsive and

adaptive to the rapid changes of production capability.

This paper proposes an emergence technique for web

based manufacturing using CNC milling machine

which uses Specialy developed holding attachment forremote machining. The proposed system can be

applied for large variety of products in small batch

sizes which requires dynamic access and real-time

monitoring capabilities The web technologies have

been employed in developing manufacturing systems

which is connected to server and client for remote

operation and monitoring. The objective of this

research is to develop an appropriate tool and

methodology with open architecture for real-time

monitoring and remote operation of networked CNC

machines. A prototype named Setup Free Machining

(Integrated CNC Milling, Reconfigurable Pin type

fixture and Internet communication) is designed for

this purpose. A new enabling technology to bringtraditional CNC machine tools on-line with combined

operation and monitoring is also presented. Issues such

as architecture design, methodology development, and

prototype implementation are addressed through a

special developed material holding attachment. It is

expected that the developed technology can be readily

applied to real shop floor environments for fully

operated remote machining with increased

responsiveness.

KeywordsWeb-based manufacturing; Remote manufacturing ;

CNC machining; Java 3D

1. Introduction

Many remote manufacturing system allow different

user at different remote location to have their designs

manufactured at remote location by manufacturing

equipments. Various Web-based manufacturing

systems have been developed in the past decade for

supporting activities in deferent life-cycle phases of

product development, including marketing, design,

process planning, production, distribution, service, etc.,

and associating these distributed product development

life-cycle activities into a globally integrated

environment using Web technologies[1]. Many product

development software tools, such as CAD systems,

CAM systems, database management systems,

knowledge-based intelligent systems, etc., at different

locations have also been integrated through Web

technologies in these Web-based manufacturing.

Although many Web-based manufacturing systemshave been developed, most of these systems were

implemented as results of research or prototypes in

industry. Compared with the computer-based systems,

such as Computer Aided Design (CAD) systems,

Computer Aided Manufacturing (CAM) systems,

manufacturing modeling and simulation systems, etc.,

the importance and usefulness of Web-based

manufacturing systems for improving product of

manufacturing industry in real remote operation have

not been widely recognized and demonstrated. Many

problems are found within a system and need to be

solved for new improved the Web-based manufacturing

systems.

Despite all the accomplishments, the available systemsare either for off-line simulation or for monitoring only.

Advanced and distributed shop floor monitoring and

remote CNC control remain impractical as web-based

applications due to the real-time constraints and lack of

equipments. To facilitate a viable web-based

environment, application servers will engage users in a

3D graphical interaction. Remote users need active and

visual supports to coordinate their efforts in a

distributed environment. There are concerns in

reducing network traffic and increasing system. Today,

shop floor engineers and machine operators still have

to meet and respond the challenges for producing

highly complex products, especially in very small

batches. To be practical, a web-based monitoring andremote operation system should also be efficient andadaptive. This paper presents a new approach for fully

remote operated CNC Milling machine using Setup

Free attachment for auto loading of workpiece and Java

3D tools remote operation and monitoring.

Manufacturing of the parts completely in all surfaces

can be done for several processes continuously without

performing setup and attendance of technician for

product evaluation and work piece setup can also be

avoided.

Remote Manufacturing and Monitoring of CNC Milling Machine

With Integrated Setup Free through Web based Virtual 3D Environment



2. Literature Review

Many Web-based manufacturing systems allow

different users at different locations to have their

designs manufactured at remote locations by expensivemanufacturing equipment such as CNC centers, robots,

and rapid prototyping machines. Several researches

concerning to utilization of web technology has been

investigated as listed bellow. In the CyberCut system[2], designers can use Web-browsers to design

components, send the process plans to a remote

controller, and execute the process plans on a three-

axis milling machine. However the system can not be

applied for complex geometry of component where

intensive manufacturing evaluation and changing the

setups is necessary. Web-based Rapid Prototyping

(RP) system called TeleRP for remote part submitting,queuing, and monitoring [3]. In this system, selection

of a valid and feasible rapid prototyping manufacturing

site registered in the RP tele-manufacturing Web

server depends mainly on two factors: site

manufacturing capability and delivery time constraints

concerning all the queues inside the site. Accuracy andvariety of material could be used for RP still lower

than milling process capability. An Internet-based

controlling of robotic system presented an experience

toward building for tele-operation shows the current

capability of networking system [4][5]. The system has

a standard network protocol and an interactive human

machine interface. Using a Web-browser, a remote

operator can control the mobile robot to navigate in the

laboratory with visual feedback and a simulated

environment map via the Internet. Many research has

been conducted for remote operation of manufacturing

equipments. Special case for machining process using

milling machine, part manufacturing still not possible

to be operated fully from remote for completeoperation. Attendance of operator is necessary for

setup of workpiece for every process.

3.The Current Connection Situation

The current state of technology for linking CNC

machine tools to the Internet is not very state-of-the-

art. Look at the desktop PC or laptop are available to

make it faster, simpler to use or more powerful.

Operating systems that come out of Microsoft on a

semi-regular basis are constantly adding more power to

the laptop or desktop PC. Contrast this situation with

that of CNC machine tools. Although the control units

are gaining more power and capabilities, their

weakness lies in connectivity to the outside world [6].

Several machine interface was designed to plug into

any network connection anywhere in the plant. If

machines had to be moved, the user could simply

relocate a network cable and plug it into the nearest

available network jack, quickly putting the machine

back online. NC part programs that are developed in

one facility can be downloaded directly to the CNC (or

to its Web server), even if that CNC is halfway around

the world. This is a nice feature for big manufacturers

who concentrate their CAD/CAM work in one location

and their manufacturing in another.

4. Auto Setup Machining Attachment

An auto setup CNC milling machine which areequipped with specially developed Setup Free

Attachment is investigated as one solution for remote

machining process. A specially designed attachmentwith setup free machining methodology has been

developed for horizontal machining center as shown in

Figure 1. By the attachment mounted on the table of a

horizontal machining center, a small size component

designed by specially developed CAD/CAM software

can be automatically machined from all of the surfacesin single process without using other fixtures[7][8].

The attachment is composed of Material rotatingdevice, Sub clamp with reconfigurable pins, Rotating

table and Material pulling device. The material rotating

device is used to hold and rotate the round bar material

for machining from circumferential surfaces. Sub

clamp which is have a pairs of reconfigurable pins is

aplied to increase the rigidity of the machining process

Figure 1: Setup Free Block Machining

Attachment.

Figure 2 : Final Clamping using reconfigurable

pins vise after Part is separated from

roundbar.



and become a main clamping device after part is parted

off from round bar material.

The attachment is suitable for machining low repetitive

small size components. Several cutting test has been

performed to evaluate the system performance.

Machining process is started by machining from

circumferential surfaces and continued by parting off

operation. After the part is parted off from round bar,sub clamp is applied to holds the workpiece. Toincrease the geometry of the part possible to be

machined, pin-type reconfigurable fixture has been

proposed to be used for clamping irregular surfaces.

A pin-type reconfigurable device is used for locating

and clamping an irregular shape of workpiece during

machining process. A pin type fixture as illustrated in

Figure 2 consists of a main body or base that contains a

two-dimensional array of orthogonal to the base roads

or pins. Each pin is protruded downward

independently, and therefore all the tips of the pins

form a cradle conforming to the shape of the

workpiece which is fixed during manufacturing

operation. Different locking methods can selectedincluding mechanical methods, pneumatic pressure and

phase change material for holding the pins after

touching the workpiece surfaces. A low-melt alloy

(bismuth-lead-tin-cadmium) is a kinds of most suitablematerial used as the holding mechanism. The low melt

temperature allows the use of hot water or induction

heating as the power source of phase change [9].

In order to determine a suitable clamping condition,

clamping evaluation has to be performed

automatically. Clamping evaluation process has been

developed to judge the machining possibility by the

succeeding algorithm[10].

5.Clamping ability evaluation

Evaluation for product manufacturability is an

extensive job. Knowledge and experience engineer still

difficult to be structured on database. Manual

evaluation of product manufacturability is not efficient

especially for low repetitive product manufacturing.

Manufacturability evaluation for machining using auto

setup machining attachment always produce the result

of unique process plan meaning that product can be

finished in single process and other sequences of machining setups are not necessary.

To restrain the workpiece during machining

operation, the clamping force should strong enough to

fix the workpiece. There are two types of supportingwhen a workpiece is held on machine tool table;

friction force and body support. Depending of directionof cutting force, one of the following clamping

condition may be happen; hold by body support, hold

by friction force and body, and hold by friction only.

Friction force restrains the workpiece for direction of

the cutting force right angle to the pins axis while the

body support restrains in the direction of pin axis.

Friction force is the main factor have to be evaluated

on workpiece holding using pin type clamping

mechanism due to the amount of force much lower than

supporting force. The amount of friction support is the

function of the normal locking force and surface

contact area between pin and workpiece surface.

Increasing the friction force by tighten the pin in

normal direction tend to defect the worpiece surface.Normal force is strictly depending on hardness of

workpiece material.First step of clamping ability

evaluation is determining usable pin through

calculating area of contact between pin and workpiece

surface which are conducted by mean of Boolean

interfere operation. The second step is calculating the

balancing the clamping force for all useable pins. Initialclamping force for every pin in one side is total

clamping force which is equal for upper and lower pin

divided by total number pins. Balancing of clamping is

performed by comparing the force resultant position in

upper and lower pins. On the ideal condition, distance

of resultant between upper and lower pins is zero.

Figure 3 shows the condition of pin configuration with

not acceptable (a) and acceptable (b) condition. When

the distance is bigger than certain value and no pin

located at opposite position of another pin resultant,

meaning that clamping balance is not suitable for the

configuration and rearrangement of pins is necessary.

The rearrangement is performed by releasing certain

pins and calculates the clamping force and balance for

such configuration. This procedure is repeated until

minimum distance between upper and lower force

resultant achieved. Part will be categorized as

unmachinable when there is no satisfies clamping

configuration possible after rearrangement process.Figure 4 shows a computer result of clamping

evaluation with pins arrangement for one operation of

machining process. Several pins have not contacted tothe workpiece, and some the others pins have partially

contacted. Non contact and less 20% partially contacte

pin on the workpiece are categorized as unusable pins.

Rearrangement of the pins is then conducted with an

algorithm by accessing other surfaces to find the

maximum numbers of usable pins. Result of the

FLR

FUR

FLR

FUR

(a) (b)

FLR

FUR

FLR

FUR

FLR

FUR

FLR

FUR

(a) (b)

Figure 3: Force resultant for determining pin

arrangement. (a) not acceptable

condition, (b) acceptable condition



machining evaluation is referred to arrange the

machining sequences.

6.Virtual Java 3D modeling

The framework SFT Machining is designed to use thepopular client-server architecture and view-control-

model design pattern. Figure 5 shows the framework in

three tiers, which is the enhanced version of that

presented. Targeting the real-time monitoring and

remote CNC machining, high efficiency for data

communication are carefully examined. The solutions

for meeting both the user requirements of rich visual

data sharing and the real-time constraints are, firstly,

using interactive scene graph-based Java 3D models

instead of bandwidth-consuming camera images for

shop floor visualization and secondly, transmitting

only the sensor data and control commands between

Java 3D models and device controllers for remote

monitoring and operation.

Java 3D is designed to be a mid to high-level fourth-

generation 3D API [11]. What sets a fourth-generation

API apart from its predecessors is the use of scene-graph architecture for organizing graphical objects in

the virtual 3D world. Unlike the display lists used by

the third-generation APIs (e.g. VRML, OpenInventor,

and OpenGL), scene graphs mercifully hide a lot of the

rending details from programmers while offering

opportunities for more flexible and efficient rendering.

Enabled by the scene-graph architecture, Java 3D

provides an abstract, interactive imaging model for

behavior and control of 3D objects[12][13].

For the sake of network bandwidth conservation, Java

3D technology is introduced as an alternative of

camera-based solution for web-based visualization. The

individual connections between Java 3D nodes arealways forming a direct relationship: parent to child.Utilizing the Java 3D technology, a machine of interest

(SFT Machine in this case) can be modeled as a scene

graph, representing its physical counterpart in the Setup

Free Machining environment. Wrapped in an applet,

the model only needs to be downloaded once from its

application server, and remains alive through applet-

servlet communications. The data transmited through

the network are limited to the data showing runtime

status of the machine. Driven by the real sensor data

,the Java 3D model can demonstrate the true behavior

of the real machine with largely improved network

performance[16].

Setup Free Attachment is designed to provide userswith a web-based and 3D virtual environment for

conduct machining process on the shop floor

environment where real-time monitoring and remote

operation are undertaken. It utilizes the latest Javatechnologies, including Java 3D and Java Servlets, as

enabling technologies for system implementation.

Instead of camera images (usually large in data size), a

physical device of interest (e.g. a milling machine, auto

setup attachment and a robot) is represented by a scene

graph-based Java 3D model in an applet with

behavioral control nodes embedded. Once downloaded

from an application server, the Java 3D model is

Figure 4: Clamping configuration of pin type setup

free attachment.

(a)

(b)

Figure 6 : Virtual Model of Pin Type Reconfigurable

Setup Free Attachment

Figure 5: Software Configuration for Virtual

Simulation



rendered by the local CPU and can work on behalf of

its remote counterpart showing real behavior for

visualization at a client side. It remains alive by

connecting with the physical device through low-

volume message passing (sensor data and user control

commands). The 3D model provides users with

increased flexibility for visualization from various

perspectives, such as walk-through and way aroundthat are not possible by using stationary optical

cameras; whereas the largely reduced network traffic

makes real-time monitoring, remote control, on-line

inspection, and collaborative trouble-shooting practical

for users on relatively slow hook-ups.

By combining virtual reality models with real devices

through synchronized real-time data communications,

the SFT allows engineers and shop floor managers to

assure normal shop floor operations and enables web-

based operation. In addition to real-time monitoring

and control, the framework can also be extended and

applied to design verification, remote diagnostics,

virtual machining, and augmented virtuality in

construction.SFT Machine with pin type reconfigurable clamping

device as illustrated in Figure 6 is a specially design

attachment which is placed on table of 3-axis

horizontal milling machine. Monitoring of actualmachining can be viewed by sending the equipment

position from various orientation (a) and (b) to the

Virtual system. Kinematic model for virtual simulation

is arranged with 3D scene scene graph architecture as

shown in Figure 7. The scene graph contains a

complete description of the entire scene. It includes the

geometry data, the attribute information, and the

viewing information needed to render the scene from a

particular point of view. All Java 3D scene graphs are

connected to a Virtual Universe object to be displayed.The Virtual Universe object provides grounding for the

entire scene. A scene graph itself, however, starts withBranchGroup (BG) nodes (although only one BG node

in this case). A BranchGroup node serves as the root of

a sub-graph, or branch graph, of the scene graph. The

TransformGroup nodes inside of a branch graph

specify the position, the orientation, and the scale of the geometric objects in the virtual universe. Each

geometric object consists of a Geometry object, an

Appearance object, or both. The Geometry object

describes the geometric shape of a 3D object. The

Appearance object describes the appearance of the

geometry (color, texture, material reflection

characteristics, etc.). The behavior of the SFT Machinemodel is controlled by Behavior nodes, which contain

user- defined control codes and state variables. Sensor

data processing can be embedded into the codes for

remote monitoring. Once applied to a TransformGroup

node, the so-defined behavior control affects all thedescending nodes. In this case study, the attachment

motion (X-Table, Rotary Indexer, Sub Clamp, and

Spindle) are controlled by their corresponding behavior

control nodes, for both on-line monitoring. As the Java

3D model is connected with its physical counterpart

through the control nodes by low-volume message

passing (real-time sensor signals and control

commands, etc.), it become possible to remotely

operate and monitor the real SFT Machine through its

Java 3D model.

A proof-of-concept prototype is implemented on top of

the framework to demonstrate its application on real-

time monitoring and remote operation through a Setup

Free Virtual system. Geometry of the parts as shown in

Figure 6 are modeled using CATIA CAD software and

exported to VRML file format. The system

configuration is modeled using the scene graph-based

Java 3D imported from VRML data using

VRMLLoader library with behavioral control nodes

embedded. It thus can behave in the same way of its

counterpart for remote monitoring at client-side,

facilitated by the model-embedded kinematics of the

real attachment.

7. Remote Device Operation and

MonitoringIn remote machining schema of the proposed system as

shown in Figure 8, it is a task of user to perform the

CAM session before sending the product data. Using

the specially developed CAM software, user must

arrange the machining process in reference to the SFT

requirement and available tools. Necessary data

formatted in ODBC which are available on the SF

server provided can be accessed during machining

preparation. Upon completing CAD session, user is

Figure 8: Web base Remote Machining Business

Scenario with auto setup CNC Milling

machine

Virtual Universe

BG

T

BaseT T

T

Table-X

Z-Column

T

Spindle

T

Table-X

VerticalMachine Tool

sClampT

T

sClampR

T

Upper Vise

T Lower Vise

Upin-1 Upin-2 Upin-.. Upin-n

T T T T

Lpin-1 Lpin-2 Lpin-.. Lpin-n

T T T T

Setup Free Attachment

T

bSlider

T

wpFeeder

T

wpRotator

Figure 7 : Java 3 D Scene Graph Architecture of

Setup Free Technology



requested to send NC program as well as product

geometry data. The received product data is then

evaluated by the SF server to determine its

machineability. Result of the machine ability

evaluation will determine whether the part can be

manufactured with pin arrangements or not.

For accepted part, the user will be notify to perform

others necessary requirement (payment etc.) which canalso be performed remotely. Operator at the server sitecan do the approval remotely before conducting the

machining process. Machining of the product data is to

be performed directly and user can monitor their

process through virtual Scene of Java.

Optionally, remote control of the SF Machine is also

possible by sending proper movement commands

through the applet-servlet-controller communication.

In order to remotely control the SF Machine, user

authentication and control right authorization must be

accomplished for the client who requests this function.

It is done by setting a bit in the control word in a data

packet that is sent to the client. If the client has

requested the control right and the bit is set, a messagewill appear on the screen notifying the user that is in

control of the machine.

8. Conclusions

In response to the distributed manufacturing

environment, this paper proposes a web-based remote

machining operation and monitoring using Setup Free

Attachment and Java 3D. The case study of this

approach show optimistic future design, monitoring,

and control distributed manufacturing. Pins type

reconfigurable vise has been proposed for clamping

irregular workpiece shape automatically from the

calculated orientation. Newly designed attachment

with reconfigurable pin clamping has been integrated

with specially developed CAD/CAM software for

clamping evaluation. The proposed model has the

potential to be used for fully unattended remote

machining in which interference of operator in

preparation of each process can be avoided.

Acknowledgments

The authors gratefully acknowledge the financial

support of International Islamic University Malaysia

(IIUM) by the sponsorship of IIUM Research Center.

The study reported is a part of the Precision

Manufacturing Research Group.

References

[1] H.Yang and D.Xue 2003: Recent research on

developing Web-based manufacturing systems: a

review Int.Journal of Prod.Res.,vol.41,no.15,3601

–3629.

[2] C. S. Smith and P. K. Wright 1996: CyberCut: A

World Wide Web Based Design-to-Fabrication

Tool. Journal of Manufacturing Systems. Vol.15,

No.6, pp.432-442.

[3] Jiang,P.and Fukuda,S. 2001 . TeleRP an Internet

Web-based solution for remote rapid prototyping

service and maintenance. International Journal of

Computer Integrated Manufacturing ,14 ,83 – 94. [4] Hu,H.S.,U,L.X.,Tsui,P.W.And Zhou,Q. 2001,

Internet-based robotic systems for

teleoperation.Assembly Automation ,21 ,143 –151.

[5] Safaric,R.,Parkin,R.M.,Czarnecki,C.A.AndCalkin,D.W. 2001. Virtual environment for

telerobotics.Integrated Computer-Aided

Engineering ,8 ,95 –104.

[6] John H. Hosmon,Connecting Your Legacy CNC

Machine Tool To The Internet,

http://www.mssonline.com/.

[7] Afzeri, T.HOSHI. 1999. Manufacturing

Evaluation and Enhancement for Setup-Free Block

Machining Technology, The 32 nd CIRP

International Seminar on Manufacturing Systems,

Leuven-Belgium, pp.289-295.

[8] Afzeri. 2004. Setup-Free Parting-off for

machining Center Work using Roundbar Steel

Material, South East Asia Iron & Steel Institute

2004 Seminar, Surabaya Indonesia. [9] A. A-Habaibeh et al. 2003, Experimental Design

and Investigation of a Pin-Type Reconfigurable

Clamping System for Manufacturing Aerospace

Components, pp 1771-1777,, Journal of

Engineering Manufacture Vol. 217 No. B12.

[10] Afzeri, A.G. E Sutjipto, A.K.M Nurul Amin, Riza

Muhida. 2005. Determination of Pin configuration

for clamping fixture by means of Solid model

contact analysis, Proceedings of the International

Conference on Mechanical Engineering 2005

(ICME2005) 28- 30 Dhaka.

[11] J. Barrilleaux. 2001. 3D User Interfaces with Java

3D, Manning Publications Co.

[12] B. Adelson. . 1999. Developing Strategic

Alliances. A Framework for Collaborative

Negotiation in Design”, Research in Engineering

Design, Vol.11, pp.133-144.

[13] P. Waurzyniak. 2000. Electronic Intelligence in

Manufacturing”, SME Manufacturing Engineering,

Vol.127, No.3, pp.44-67.

[14] J. van den Broecke.2000. Pushlets, Part 1: Send

events from servlets to DHTML client browsers,

JavaWorld.

[15]Lihui Wang ,Peter Orban,Andrew

Cunningham,Sherman Lang. 2004. Remote real-

time CNC machining for web-based

manufacturing, Robotics and Computer-Integrated

Manufacturing, 20 563 –571.[16]Yongmin Zhong, et all. 2005. A methodology for

solid modeling in a virtual reality environment,

Robotics and Computer-Integrated Manufacturing

,21 528 –549.

[17] Sotiris L.Omirou, Antigoni K.Barouni. 2005.

Integration of new programming capabilities into a

CNC milling system, Robotics and Computer-

Integrated Manufacturing 21 518 –527.

Documents

Pin type clamping