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Document 1932121
THE DEVELOPMENT OF A DESIGN PROTOCOL FOR PRODUCTION OF HIGH SPEED COINING DIES. by
BURGER ADRIAAN KOTZE
Submitted in partial fulfillment of the requirements for the degree
MASTER OF ENGINEERING (MECHANICAL)
in the
FACULTY OF ENGINEERING
UNIVERSITY OF PRETORIA
OCTOBER 2000
© University of Pretoria
DISSERTATION SUMMARY
THE DEVELOPMENT OF A DESIGN PROTOCOL FOR PRODUCTION OF HIGH SPEED COINING DIES. B.A.KOTZE
Supervisor:
N .D.L. Burger
Department:
Mechanical and Aeronautical Engineering
Pr.Eng MEng(Mech),GCC(Mech)
UNIVERSITY OF PRETORIA
In the production process of coining dies various obstacles are encountered. Due to the
complexity of the process and the system, many of the underlying problems remain
unidentified just to repeat themselves at a later stage.
The project was done to provide the client with a better understanding of the major factors
that influence the development process. If the source of a problem can be identified and is
understood a course of action can be determined that will prevent the problem from
reoccurring.
The project focus was on the behaviour of the die and coin material during the deformation
and heat treatment processes.
The behaviour of the material was explained from a
theoretical point of view and methods to control this behaviour were discussed.
A design protocol was established, which will enable the developer to achieve improved
results during the development process. The main objective of the protocol is to improve
consistency in the results that are obtained during the development process.
ABSTRACT Title:
THE DEVELOPMENT OF A DESIGN PROTOCOL FOR PRODUCTION
OF HIGH SPEED COINING DIES.
Author:
RA. Kotze
Supervisor:
N.D.L. Burger
Pr.Eng MEng(Mech),GCC(Mech)
Department: Mechanical and Aeronautical Engineering
UNIVERSITY OF PRETORIA
Degree:
M.Eng (Mech)
The degree of success with which coining dies are manufactured greatly influences the
total development time and therefore the total success of a project. In the production
process of the coining dies, various obstacles are often encountered. These obstacles retard
the project and adversely affect the profit margin of the company.
There are no scientific models in place by which these dies can be developed.
Consequently the development and production process is done on a trial and error basis.
Due to the complexity of the process and the system many of the underlying problems
remain unidentified just to repeat themselves at a later stage.
The major factors determining the success of a project, from the perspective of the
development department, is the total project time, the quality of the product (Le. the dies
and the final coins) and die life.
The purpose of the project was to analyse the development process in detail and to develop
a design protocol, which will guide the developer during development.
The design
protocol will suggest a procedure to follow when developing dies. The design protocol will
assist the die developer in locating the source of certain problems systematically.
The project was done to provide the client with a better understanding of the major factors
that influence the development process. If the source of a problem can be identified and is
understood the proper action could be detennined and employed to prevent the problem
from reoccurring. This project will serve as the basis for further development efforts in
this field.
During the course of the study emphasis was put on the development and production of the
high speed coining dies. The major factors that influence the development process were
identified and development tests were done to establish the influence of each of these
factors. The development process was broken down into components and each component
was evaluated separately.
The test focus was on the behaviour of the die and coin material during the deformation
and heat treatment processes. For each test a significant amount of test data was collected.
The results of the tests were analysed and evaluated. The behaviour of the material was
explained from a theoretical point of view and methods to control this behaviour were
discussed. The test results were generalized to apply to all development projects.
The source of many of the problems that are encountered during the development and
production process were identified and quantified with the test results. On the basis of
these results the design protocol was established. Many of the problems encountered are
process control related. Solutions to improve the process control are discussed in the
report.
The design protocol will enable the developer to achieve improved results during the
development process. The design protocol can also be used as a tool to establish the cause
and recourse for certain development and production problems. The main objective of the
protocol is to improve consistency in the results that are obtained during the development
process.
The design protocol will enable the developer to implement a faster and more efficient
development process, while avoiding problem areas, thereby reducing the total project time
and increasing product quality and profit margins.
ACKNOWLEDGEMENTS I would like to thank God for giving me the strength and ability.
"I would rather walk with God in the dark than go alone in the light."
Mary Gardiner Brainard
I would like to thank the following people and institutions for their contributions and
support for making this project possible.
• Mr. Danie Burger for his support and academic guidance.
• Mr. Rudolf Ottermann for managing the project.
• The S.A Mint for their resources and support. Especially Mr. Pieter Goosen and
everybody at the deVelopment department who assisted me unconditionally.
• LGI (Pty) Ltd. and CMTI Developments (Pty) Ltd. for their fmancial contributions.
• THRIP for supporting technological research and for their financial contribution.
• My fiance, Elanie, for her emotional support.
LIST OF SYMBOLS AND ABBREVIATIONS
Rockwell B Hardness Rockwell C Hardness Yield Strength Strain Vickers Hardness CONTENTS PAGE 1
PROLOGUE
SECTION A
DIE DEVELOPMENT
5
INTRODUCTION
CHAPTER 1
4
MATERIAL SELECTION
12
1.1
Introduction
12
1.2
Dies
13
1.2.1
Introduction
13
1.2.2
Material analysis (Tool Steel)
14
1.2.3
Tensile Tests (Tool Steel)
27
1.2.4
Conclusion
32
1.3
Blanks
33
1.3.1
Introduction
33
1.3.2
Material Analysis (Steel)
34
1.3.3
Tensile Tests (Steel)
35
CHAPTER 2
COIN DESIGN
36
2.1
Introduction
36
2.2
Design Selection
37
CHAPTER 3
BLANK DESIGN
41
3.1
Introduction
41
3.2
Blank production
41
3.3
Blank Qualification
45
3.4
Conclusion
48
CHAPTER 4
DEVELOPMENT TESTS 49
4.1
Introduction
49
4.2
Test 1: Introduction to Development Tests
51
4.3
Calibration of Hobbing Press
53
4.4
Measuring Procedure
59
4.5
Heat Treatment
63
4.6
Test 2: Heat Treatment
66
4.7
Test 3: Heat Treatment
73
4.8
Test 4: Hobbing
86
4.9
Stress Concentrations
108
SECTIONS
HIGH SPEED COINING
113
CHAPTER 5
COINING TESTS
114
5.1
Introduction
114
st
5.2
Test 5: 1 Coining Test
115
5.3
Test 6: 2nd Coining Test
120
5.4
Test 7: 3rd Coining Test
124
5.5
Calibration of High Speed Coining Press
130
SECTIONC
DESIGN PROTOCOL
134
CHAPTER 6
DESIGN PROTOCOL
135
6.1
Introduction
135
6.2
Design Protocol
136
6.3
Conclusion
141
LIST OF APPENDICES
APPENDIX A
Material Analysis
APPENDIXB
Tensile Test Results
APPENDIXC
Specification Drawings
APPENDIXD
RSA Circulation Coin Specifications.
APPENDIXE
Measuring Procedure
APPENDIXF
Test 4 Results
1
PROLOGUE A successful development effort and a short project time are crucial if the S.A Mint is to
succeed in the competitive international industry of coin manufacturing.
Scientific
knowledge in the process will be an asset to the company and will guide the company in
deciding where further development efforts are necessary.
The degree of success with which coining dies are made, greatly influences the total
development time and therefore the total success of a project. In the production process of
the coining dies various obstacles are often encountered. These obstacles retard the project
and adversely affect the profit margin of the company.
There are no scientific models in place by which these dies can be developed.
Consequently the development and production process is done on a trial and error basis.
Due to the complexity of the process and the system, many of the underlying problems
remain unidentified just to repeat themselves at a later stage.
A detailed functional analysis was done on the entire development and production process.
This was necessary to identifY the problem areas, to get an overall picture of the process,
and to determine all the factors that playa role in each process. The inter-relationship of
2
PROLOGUE
the different activities was also established. A report was compiled and delivered to the
Mint. The report indicated certain problem areas, which need to receive attention. The
functional analysis report will not be included in this report.
The purpose of the project was to analyse the development process in detail and to develop
a design protocol, which will guide the developer during development.
The design
protocol will suggest a procedure to follow when developing dies. The design protocol will
assist the die developer in locating the source of certain problems systematically.
The project was done to provide the client with a better understanding of the major factors
that influence the development process. If the source of a problem can be identified and is
understood the course of action can be determined that will prevent the problem from
reoccurring. This project will serve as the basis for further development efforts in this
field. The test focus was on the behaviour of the die and coin material during deformation
and heat treatment processes.
In Chapter 1 the material that was used for the project will be analysed. Chapter 2 and 3
will deal with the design of the coin and the production of the blanks. All the development
tests that were done on the production of the master punch are discussed in Chapter 4.
Chapter 5 contains the results of the coining tests and the design protocol that was
developed is discussed in Chapter 6.
A project overview is included in Figure 1 to show what was done during the project and
to show how the structure of the report was compiled.
S.A Mint Project Overview
I'ROLOGUE
I
I
I
SE!::Dru:!A
SE!::IIru:! a
IICIlQrlC
llIe Developmem
H1&b Speed CCIInIn;
I
CHAEIIB6
Deslln Protocol
I
~
I I
CfAEIDU
MoteJillllleIecHon
Coin De11ln
1.1 Inlrodndlon
I
.cIW!.IJIU
.!:IW!IlIU
C-DI Tests
Bin Design
Development Tests
S.ll_.cOnn
I
1.3 Blmb
I
I
1.2.1 Introduction
1.3.1 '_uctIon
1.2.2 MoteJiIll Alllllysi.
1.3.2 MaleJilll A..,.IJ
• HBrdnes, Test
I
II.l De,lgn ProlDcoi
~
Y
2.1 I _ o n
-1
H3.2
3.1 l_uctIon
'1.2 Deugn Selecllon
I
81_ ProducOonJ
H,.3 Bin Q..-onl
• Compoatim Majv ••
y
• Hardnc:s. Ten
I
6.3 Cood..lon
I
I
!.2 Te.t!: l"CoIlllngTe.t
S.] Te.t6, l'" CCIInIn; Tett
CaiIlIng will .... wiIl.1!halbw
Coiniola with d'" with de<;>
dOl", u.hgnamal and .aft
<Iesi&n
3.4 Cooduslon
I
b_
U Toll 7: rCoInInl Te"
Tnmllvtnc
CoinioI! with d'" with lqe dome
uai1a namal and soft blanb
prenes
• NantlIIlSamples
• _=lid Samples
I
I
I
4.2 Test!
4.3 Cllllbrafion or
HoblllDl_n
4.4 Me. Wing Procedw'e
4.! Heal Tre..-nl
P"'sscalilro!Jldto<mrure
Estab6shprocedute toel1l\l!1!
1.2.4 Coodus.on
IlIrohJ:O:m to deveiopnent
test!
Hesltte_p:a:... of
2363TooI Steel
accurate n",*" <lnirt!
bob1illltr""...·
Project Overview
accurate results.
I
I
4.6 TesU:
Heat Treabnent
Heat TreaClnent
Quatijl\o ope chanp 01:
die <lnirt!h>at_
4. 7 Te.t3:
Olluu,.,,,,, _r~
shape cllar!!e ofdie <lnirt!
hesltre_
4.8 Test4: HO_I
4.9 stress concentradom
'"' E _ shape chanp of
puncllo. duri1a~ and
heal tre_ p:a:esas,
• EVIl_ die biank CO!¥!
..pI
I
Proc.dute dewl:Jped fa
coIibmtir;g ca.it1! JIOIIS"
I
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FIGURE 1
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!o! CIIII_on or cOllllng
• LqeSornp""
Lonaiudi1al
.SmollSamples
Lonaindlnal
I
I
1.303 TonsOe Telts
1.2.3 To..U. T••ts
Introduction
I
1.2 DIe.
Compodicn Majva.
Chern. Blsna DistributiJn
Mkrartructin
Nood_tMoT,"IilS
U
4.1 lDtroducliOD
I
•
•
•
•
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~tiA:fII.i :i
Evaluating tho efIIoct o f _
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