UNIVERSITI TEKNIKAL MALAYSIA MELAKA
APPLICATION OF TRIZ METHODOLOGY IN CASTING
PROCESS: A CASE STUDY
This report submitted in accordance with requirement of the Universiti Teknikal Malaysia Melaka (UTeM) for the Bachelor Degree of Manufacturing Engineering
(Manufacturing Process) with Honours.
by
GAN KOK HWAY
i
ABSTRACT
ii
ABSTRAK
iii
DEDICATION
iv
ACKNOWLEDGEMENTS
First of all, I would like to express my gratitude to my university, (Universiti Teknikal Malaysia, Melaka) UTeM for giving me the chance to be involve in this project. Besides that, I would like to express my warmest gratitude and thankfulness to my supervisor, En. Ammar bin. Abd. Rahman for his supervision, guidance, trust, advice and support, encouragement, and assistance towards me throughout this project. Besides that, I also like to express my gratitude to En. Zolkarnian for helping me in my project by giving advices and guidance.
v
TABLE OF CONTENT
Abstract i
Abstrak ii
Dedication iii
Acknowledgement iv
Table of Contents v
List of Figures ix
List of Tables xii
List of Abbreviations xiii
1. INTRODUCTION
1.1 Case study background 1
1.2 Problem statement 2
1.3 Objectives 2
1.4 Scope 3
1.5 Organization of project 3
2. LITERARUTES REVIEW
2.1 Casting process 5
2.2 Expendable mold casting 5
2.2.1 Sand casting process 6
2.3 Casting defects 7
2.3.1 Metallic projection 8
2.3.1.1 Veining or Finning 8
2.3.1.2 Cracked or broken mold 9
2.3.1.3 Sweating or dip air 9
2.3.2 Cavities 10
2.3.2.1 Blowholes, pinholes 10
2.3.2.2 Dispersed shrinkage 11
vi
2.3.2.4 Internal or blind shrinkage 12
2.3.2.5 Corner or fillet shrinkage 12
2.3.2.6 Centerline or axial shrinkage 13
2.3.2.7 Macroshrinkage, microshrinkage or shrinkage porosity 13
2.3.3 Discontinuities 13
2.3.3.1 Hot cracking 14
2.3.3.2 Hot tearing 14
2.3.3.3 Quench cracking 15
2.3.3.4 Cold shut or cold lap 15
2.3.4 Defective surface 16
2.3.4.1 Surface folds or gas runs 16
2.3.4.2 Metal-mold reaction, orange peel and alligator skin 16
2.3.4.3 Sink marks, draw and suck-in 17
2.3.4.4 External slag inclusions 17
2.3.4.5 Metal penetration 18
2.3.4.6 Dip coat spall, scab 18
2.3.5 Incomplete casting 19
2.3.5.1 Mis-run 19
2.3.5.2 Poured short 19
2.3.6 Incorrect dimension or shape 20
2.3.6.1 Mutilation 20
2.3.6.2 Improper shrinkage allowance 21
2.3.6.3 Casting distortion 21
2.3.7 Inclusion or structural anomalies 22
2.3.7.1 Slag, dross or other ceroxide innclusions 22
2.3.7.2 Hard spots 22
2.4 Introduction to TRIZ 23
2.4.1 The history of TRIZ 23
2.4.2 Invention problems 24
2.5 The TRIZ process step-by-step 28
2.5.1 Identifying problems 28
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2.6 ARIZ 31
3. METHODOLOGY
3.1 Project planning 32
3.2 Gantt chart 34
3.3 TRIZ methodology 36
3.4 Mini-ARIZ 36
3.5 TRIZ, 40 innovative principles 37
3.5.1 Engineering parameter and 40 innovative principles 37
3.6 Explanation tool usage 39
3.6.1 Diagnostic Phase 39
3.6.1.1 Diagnostic properties 40
3.6.2 Reduction Phase 40
3.6.2.1 Establish functional model of study for reduction 40 3.6.2.2 Explanation of functional model of study 41
3.6.3 Transformation 42
3.6.3.1 Transformation properties 43
3.6.3.2 TRIZ, 40 principles from contradiction matrix 43
3.6.4 Verification 45
4. CASE STUDY
4.1Case study background 46
4.2Case Study: Sand Casting 47
4.2.1 Procedures of Sand Casting 48
4.2.2 TRIZ Implementation 49
5. RESULT
5.1 Case study results 50
5.1.1 Metallic projection (sweating) 51
5.1.2 Surface cavity (pinholes) and rough surface 52
5.1.3 Flash formation 54
6. DISCUSSION
viii
6.1.1 Diagnostic phase 56
6.1.1.1 Diagnostic statement 57
6.1.1.2 Operative zones 57
6.1.1.3 Final ideal result 58
6.1.2 Reduction phase 58
6.1.3 Transformation phase 61
6.1.3.1 Proposed solution 63
6.2 Solving problem of surface defect 64
6.2.1 Diagnostic phase 65
6.2.1.1 Diagnostic statement 65
6.2.1.2 Operative zones 65
6.2.1.3 Final ideal result 66
6.2.2 Reduction phase 66
6.2.3 Transformation phase 71
6.2.3.1 Proposed solution 73
6.3 Verification of solution 79
6.3.1 Diagnostic phase 79
6.3.1.1 Verification of solution on casting surface and metallic projection
80
6.3.1.2 Verification of solution on removing casting’s flash formation
83
7. CONCLUSION
7.1 Conclusion of TRIZ implementation in case study 84
7.2 Summary of result 86
7.3 Suggestion on future work 87
REFERENCE 88
ix
LIST OF FIGURES
2.1 Joint flash or fins. 8
2.2 Veining or finning. 8
2.3 Cracked or broken mold. 9
2.4 Sweating or dip air. 9
2.5 Blowholes, pinholes. 10
2.6 Dispersed shrinkage. 11
2.7 Open or external shrinkage. 11
2.8 Internal shrinkage. 12
2.9 Corner or fillet shrinkage. 12 2.10 Centerline or axial shrinkage. 13
2.11 Macroshrinkage. 13
2.12 Hot cracking. 14
2.13 Hot tearing. 14
2.14 Quench cracking. 15
2.15 Cold shut/lap. 15
2.16 Surface folds/ gas run. 16
2.17 Metal mold reaction. 16
2.18 Sink marks. 17
2.19 External slag inclusion. 17
2.20 Metal penetration. 18
2.21 Dip coat spall, scab. 18
2.22 Mis-run. 19
2.23 Poured short. 19
2.24 Mutilation. 20
2.25 Improper shrinkage allowance. 21
2.26 Casting distortion. 21
2.27 Slag, dross / other. 22
2.28 Hard spots. 22
x
2.31 Ideal Solution May Be Outside Your Field. 25 2.32 TRIZ Approach to Problem Solving. 28
3.1 Flow Chart of Project Planning. 33
3.2 Mini-ARIZ. 36
3.3 Flow chart of Mini-ARIZ used. 38 3.4 Structure of the relationship of the OZ with system
and environment.
39
3.5 Functional model of study. 41 3.6 Structure of interaction of the key concepts of TRIZ. 43 3.7 Demonstration of usage. 44 3.8 Illustration of principles selection. 44
4.1 Sand casting experimental sets. 47 4.2 Mold for sand casting with indicators. 47 4.3 Sequential demonstration of the procedures. 49
5.1 Arranged pictures of casting defects with picture indicators. 50 5.2 Sweating found on the casting. 51 5.3 Porous surface on the casting. 52 5.4 Formation of flash on parting line region. 54
6.1 Diagnostic phase. 57
6.2 Reduction phase. 58
6.3 Functional model of study for flash reduction. 60 6.4 Sequential steps of preparing silicone solution to apply,
distributes and removal of pattern.
64
6.5 Functional model of study for making mould surface smoother and removal of moisture.
68
6.6 Heating process to remove moisture, temperature at 120oF 74 6.7 Simple test conducted, Gypsum quantity varies from left to
right at 10%, 5%, 4% & 3%.
76
xi
gypsum, picture at left indicates sectioned side view and picture at right indicates the top view.
6.9 Easy extraction from the greensand mould, picture at left indicates before pouring and right indicates a clear extraction.
78
6.10 Picture (a) casting after TRIZ improvement and (b) defect of metallic projection.
80
6.11 Picture (a) after TRIZ improvement, (b) and (c) indicates rough surface before TRIZ improvement.
80
6.12 Pictures of comparison between casting surface, without camera flash at left and with camera flash at right.
81
6.13 Comparison of microscopic images under 3x magnification between castings, improved surface located on the left showing denser grain structure.
82
6.14 Microscopic images under 50x magnification between castings surface, improved surface (a) showing reduction in surface cavity compared (b).
82
6.15 Comparison between castings surface with bare eye observation, improved surface on the left and before improvement on the right.
83
6.16 Comparison at parting line area using bare eye, improved finishing on (a) and before improvement on (b).
83
xii
LIST OF TABLES
2.1 Levels of Inventiveness. 27
2.2 List of 39 Engineering Parameters and 40 Principles. 29
3.1 Gantt Chart PSM 1. 34
3.2 Gantt Chart PSM 2. 35
4.1 Tin element facts. 46
5.1 Defects explanation. 51
5.2 Sweating defect (metallic projection). 51
5.3 Rough surface defect. 52
5.4 Flash defect. 54
6.1 Operative zones affecting the formation of flash. 57
6.2 Table of summary. 60
6.3 40 Innovative principles for parting line removal. 61 6.4 Principle to remove parting line. 62
6.5 Table of solution (silicone characteristic). 64 6.6 Operative zones affecting the surface defect. 65
6.7 Table of summary. 68
6.8 40 innovative principles for solving casting surface problem.
69
6.9 Table of principles frequencies. 71 6.10 Principles to remove surface defects. 72 6.11 Reasons for Gypsum/plaster mixture. 76 6.12 Experiment result through observation. 76 6.13 Table before and after TRIZ implementation. 79
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LIST OF ABBREVIATIONS
ARIZ
-
Algorithm for Inventive Problem Solving
PSM
-
Project Sarjana Muda
TRIZ
-
Theory Of Inventive Problem Solving
USSR
-
Union of Soviet Socialist Republics
Vol.
-
Volume
CICO
-
Cluster-In-Cluster-Out
CROST
-
Constructive Result & Resource Orientated Strategy of
Thinking/ Transformation
1
CHAPTER 1
INTRODUCTION
1.1
Case Study Background
(Teoriya Resheniya Izobretatelskikh Zadatch/ theory of inventive problem solving),
TRIZ methodology is a theorem use to creating an ideal solution in solving a
problem, this report aims to seek out the application of TRIZ methodology for ideal
solution to curb with problems found in casting process. The main objective of
conducting this study is to see for the compatibility of TRIZ methodology in
providing an existing problem an ideal solution. The application of TRIZ
methodology in problem solving should demonstrate how effective the solution are
based on the tools introduced by the TRIZ. Implementation of the project aims to
come out with an ideal solutions to the problems found in casting.
TRIZ is a non-intuitive problem-solving method based on logic and data analysis,
which accelerates the ability to solve problems creatively. TRIZ also provides
predictability, and reliability due to its structure and algorithmic approach. TRIZ is a
(Russian) acronym for the “theory of inventive problem solving,” which was
developed on the study of the patterns of problems and solutions, not on the
spontaneous and intuitive creativity of individuals or groups. In the formulation of
TRIZ methodology, more than 3 million patents have been analyzed to decipher the
patterns that predict breakthrough solutions to problems. TRIZ has always been
famous with solving problem and emphasizing on the ideality of the solution, the
enhancement of ideality is done by overcoming contradictions, mostly with minimal
2
Research in this topic is to implement the TRIZ methodology into solving the
problem arises during the process of casting. The project tends to see the
compatibility of TRIZ methodology in solving out the problem raised in casting
process.
1.2
Problem Statement
Technique of solving problem is increasingly important in the current engineering
field.
However, conventional ways of solving the problem faced in engineering field is
nothing more than a mere trial and error techniques, this can be costly, time
consuming and lack of practicality on the ideas generated.
Conventional ways of solving the problem is done via the trial and error.Inability to
understand its problem have always lead engineer to come out with unsuitable
solution and caused waste of time and energy. In this case, the study conducted in
this report tends to solve problem faced in casting process.
Hence, in order to solve the problem surfaced by case study of casting process; a
suitable methodology will be used to overcome the problem during casting process.
Problem will be investigated and the best solution will be generated to enhance the
ideality of current existing solution.
1.3
Objectives
1. To adopt TRIZ methodology in problem found in casting process and come out
with an ideal solution.
2. To construct a model for problem solving based on TRIZ methodology and
moving towards the ideal solution (IFR) by:-
3 ii. Increasing the ideality of solution
iii. Implementing TRIZ into casting problem solving.
3. To further understand and improve current existing solution in casting process.
1.4
Scope
This project aimed to focus on how to solve problem arise from casting process using
TRIZ methodology and it should covers the scope as stated below:
1. Apply TRIZ methodology into solving problem arising in sand casting.
2. Unified the TRIZ tools used in the project.
3. The tools of TRIZ involved in generating ideal solution are:
i. Mini-algorithm of inventing (Mini-ARIZ).
ii. 40 innovative principles of TRIZ.
4. Verify solution effectiveness.
1.5
Organization of the project
Generally, organization of the report consists of six chapters, namely introduction,
literature review, methodology, result, discussion and conclusion for future works.
All the structure details for each chapter had been shown below:-
a) Chapter 1 : Introduction
This chapter contains introduction and description about the
project title. Generally, it covers the background, problem
statement, and objective, scope of study and thesis contents. It
4 b) Chapter 2 : Literature review
Throughout this chapter, information relevant to the study will
be included, it is the topic to study for better understanding.
Subsequently, summarization of important information is done
here.
c) Chapter 3 : Methodology
This chapter contains information on how to conduct the
analysis on the case study. Methodology show here provides
the information on how to perform and conduct the project.
d) Chapter 4 : Case study
Chapter 4 explains about the sequential steps of conducting the
experiment, it consists of vital information need to know in
order to conduct the experiment correctly.
e) Chapter 5 : Result
Chapter 5 is regarding the result obtained from the case study
experiment, it is conducted to identified all the defects formed
during the experiment.
f) Chapter 6 : Discussion
This chapter contains vital information that elaborates the
solution for solving the sand casting problem. Result obtain
here must apply the methodology describe in chapter 3.
g) Chapter 7 : Conclusion
Finally, this chapter concludes the main findings for the report.
Besides, the recommendation for further study will be
5
CHAPTER 2
LITERATURE REVIEW
2.1
Casting Process
Casting is a manufacturing process by which a liquid material is pour into a mold
contains a hollow cavity of the desired shape, and then allowed to solidify. Solid
casting is then eject or broken out to complete the process. Casting can also be use to
form hot liquid metals and often used for making complex shapes that would be
otherwise difficult or uneconomical to make by other methods. Casting processes
have been divided into two distinct groups, which are the expendable and
non-expendable mold casting. Expendable molds are use only once and other molds are
made of metal (permanent molding and die-casting) and can be used repeatedly.
Pattern must be removable from the mold without damage, and the casting must be
removable from the mold or die without damaging the die and the casting product
(Anonymous, 2008).
2.2
Expendable Mold Casting
Expendable mold casting is a generic classification that includes sand, plastic, shell,
plaster, and investment (lost-wax technique) moldings. This method of mold casting
involves the use of temporary, non-reusable molds and usually need gravity to help
6 2.2.1 Sand Casting Process
One of the most popular and yet simplest types of casting that has been use for
centuries will be sand casting. Sand casting can be used for smaller batches
production compared to permanent mold casting and at a very reasonable cost.
Besides of allowing manufacturers to create products at a low cost, there are other
benefits to sand casting, such as very small size operations. From castings that fit in
the hand’s palm to train beds (one casting can create the entire bed for one rail car), it
can all be done with sand casting. Sand casting also allows the casting of most metal
depending on the type of sand used for the molds. Casting is a process by which a
fluid melt is poured into a mold, allowed to harden within the mold, and then ejected
or revealed to make a fabricated part or casing. Four main elements are required in
the process of casting: pattern, mold, cores, and the part. Pattern, the original
template from which the mold is prepared, creates a corresponding cavity in the
casting material (Cambridge Encyclopedia Vol. 13, 2008).
In this process, sand mixed with binders and water is compacted around wood or
metal pattern halves to produce a mould. Mould is removed from the pattern,
assembled with cores, if necessary, and metal is poured into the resultant cavities.
After cooling, moulds are broken to remove the castings. This process is suitable for
a wide range of metals (both ferrous and non-ferrous), sizes and shape complexity.
(Ravi, 2004). Sand casting primarily uses green (moist) sand, and it has almost no
part weight limit whereas dry sand has a practical part mass limit of 2300-2700 kg.
Minimum part weight ranges from 0.075-0.1 kg. Sand is bonded together using clays
(as in green sand) or chemical binders, or polymerized oils (such as motor oil). Sand
can be recycled many times in most operations and requires little additional input.
The term green sand does not refer to color, but to the fact that a raw sand and binder
mixture has been tempered with water. Sand molding is a versatile metal-forming
process that provides freedom of design with respect to size, shape, and product
quality (Anonymous, 2008).
Plaster casting is similar to sand molding except that plaster is substituted for sand.
Plaster compound composed of gypsum, strengthener and water, parts were typically
7
ornaments. The finished product of plaster casting has a very high surface resolution
and fine tolerances, it is inexpensive but low production. Plaster casting cannot be
use for non-ferrous metal, gypsum in the plaster will slowly reacts with the iron; the
maximum temperatures of plaster casting is limited to 1200o, it limits the material
cast using this methods. A thin layer of parting film is usually spray to the pattern to
prevent mold from sticking the pattern, this step is necessary in the preparation step.
Unit of the preparation will be shaken to allows the filling of the small cavities
around the pattern, it is then dried at the temperatures between 120o to 260o and
preheated when molten metal is poured in (Ravins et. al, 1989).
2.3
CASTING DEFECTS
There are only seven categories of casting defects, which have been established.
These defects are (Donohue et. al., 1999):
(a) Metallic Projections
(b) Cavities
(c) Discontinuities
(d) Defective Surface
(e) Incomplete Casting
(f) Incorrect Dimensions or Shape
