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.