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

FACULTY OF MANUFACTURING ENGINEERING

2008

i

ABSTRACT

This report discussed about how to solve problem arise from casting process by using

the TRIZ Methodology. TRIZ methodology is a theorem use for creating an ideal

solution in solving a problem, it is done by solving the contradiction arise in the

problem. During the project, casting process is selected as the case study for

application of TRIZ methodology in order to solve the defects arise in the process;

theory designed aims to solve the problem innovatively. Initial part of the report

discussed about casting process and followed by the common type and cause of

defects found in casting process. Further on, discussion in the report continue to

discuss about the solution towards casting defects, it is done by using TRIZ

methodology (Mini-ARIZ and 40 innovative principles). Principles selected will be

applied in this report, it tends to show how to solve manufacturing problem in casting

and come out with a concrete solution, which is cost effective and efficient from

various aspect. As for result and outcome of experiment, TRIZ implementation

brings a major impact towards the result of casting. During the case study, TRIZ

application has successfully solved four main problems identified in the casting

experiment; these defects include surface cavities defects (pinholes), flash formation,

rough surface and metallic projection. TRIZ application has successfully solved the

problem by generating useful guidance and provides direction in future steps. Report

also include the result and verification of solution effectiveness, solution generated

outcome has been verified and proven to be effective by experiment. As in general,

TRIZ successfully solve the problem of flash formation, rough surface, metallic

projection and reduce the formation of surface cavities.

ii

ABSTRAK

Secara umumnya, laporan ini adalah mengenai keberkesanan sistem penyelesaian

TRIZ dalam mengatasi masalah yang dihadapi dalam proses tuangan. TRIZ

merupakan teori yang digunakan untuk menyelesaikan masalah, ia berfungsi dengan

menyelesaikan masalah percanggahan yang terbentuk di dalamnya. Sebagai

permulaan, perbincangan projek bermula dengan pengenalan jenis-jenis kerosakan/

ciri-ciri tidak dihendaki yang terbentuk dalam prosess tuangan dan sebab

pembentukannya. perbincangan turut merangkumi bahagian penyelesaian masalah

melalui cara TRIZ (Mini-ARIZ dan 40 innovative principles). Prinsip-prinsip yang

dijanakan dari sistem TRIZ akan digunakan dalam experimen proses tuangan, ia

bertujuan menunjukan keberkesanan TRIZ dalam penjanaan penyelesaian yang

berkos rendah dan berkesan. Laporan ini turut menbincangkan tentang keputusan

dalam experimen yang dijalankan, kehadiran TRIZ telah menpengaruhi cara

penyelesaian dan keputusan yang dijanakan, dan ia dapat dikesan berdasarkan

experimen yang dijalankan. Secara umumnya, TRIZ telah membantu dalam

penyelesaian 4 masalah utama; antara masalah yang dinyatakan adalah masalah

keliangan, pembentukan flash, permukaan kasar (rough surface) dan pembentukan

besi di bahagian luar daripada bentuk tetapan (metallic projection). Kehadiran TRIZ

member kesan yang menggalakan dalam penjanaan cara penyelesaian, ini adalah

kerana ia telah menyelesaikan masalah dengan baik melalui panduan yang

mencukupi. Selain itu, kertas kajian ini turut merangkumi keputusan dan

pengenalpastian keberkesanan cara penyelesaian. Cara penyelesaian yang dijanakan

telah dibuktikan berkesan melalui experiment proses tuangan, perbandingan hasilnya

turut menbuktikan hasil bentuk tuangan selepas applikasi TRIZ adalah lebih baik.

iii

DEDICATION

To my beloved parent, aunts, siblings’ and cousins.

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.

Last but not least, I would like to thank my family who gave me the encouragement

and support, strength and inspiration to perform this project to the end. At the same

time, I would like to thank my coursemates for providing ideas, advices, support and

comments in order to accomplish my project.

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

2.3.2.3 Open or external 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

2.5.2 Formulate the problem: the prism of TRIZ 28

2.5.3 Search for previous well-solved problem 29

vii

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

4.1 Case study background 46

4.2 Case 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

6.1 Solving problem of flash formation 56

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

APPENDIX 90

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

2.29 General Problem Solving Model. 23

2.30 Limiting Effects of Psychological Inertia. 24

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

6.8 Discardable film or covers of mixture of greensand and 77

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

7.1 Summary of solutions. 88

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

6.14 Surface roughness result. 81

xiii

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

Psi - Pound square inch

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

introduction of resources.

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:-

i. Using 40 principles of innovation to create a good solution.

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

is done to enable an easier overview of the project.

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

included at the same time.

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

force molten fluid into casting cavities (Anonymous, 2008).

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

made of the plaster casting are lock components, gears, valves, fittings, tooling, and

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 260

o 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

(g) Inclusions or Structural Anomalies