Finite Element Analysis and Design Optimization of Platen for Injection Molding …mechnovation.weebly.com/uploads/6/1/1/4/61141041/sa… · · 2015-10-13This is to certify that

Finite Element Analysis and Design

Optimization of Platen for Injection Molding

Machine

By

Rahul M. Thaker

(Enrolment No. 130321708509)

Guided By

Ms. Neha B Joshi

Assistant professor, Mech. Engg. Dept.,

L. J. Institute of Engineering and Technology,

Ahmedabad, Gujarat

A Thesis submitted to

Gujarat Technological University

In partial fulfilment of the requirements for

The Degree of Master of Engineering in [CAD/CAM]

May-2015

L. J. Institute of Engineering and Technology,

LJ campus, S.G. Highway, Sarkhej,

Ahmedabad - 382210.

ii

CERTIFICATE

This is to certify that research work embodied in this project report entitled “Finite

Element Analysis and Design Optimization of Platen for Injection Molding

Machine” was carried out by Mr. Rahul M. Thaker (Enrollment No. 130320708509)

at L. J. Institute of Engineering and Technology, Ahmedabad for partial fulfillment of

M.E. degree to be awarded by Gujarat Technological University. This research work has

been carried out under my supervision and is to the satisfaction of department.

Date:

Place: Ahmedabad

Ms. Neha B. Joshi

Asst. Prof., PG. Dept.

LJIET, Ahmedabad

Ms Gayatri S. Pandi (Jain)

HOD, PG Dept.

LJIET, Ahmedabad

Dr. A. C. Suthar

Director

LJIET, Ahmedabad

iii

INDUSTRY CERTIFICATE

iv

COMPLIANCE CERTIFICATE This is to certify that research work embodied in this thesis entitled “Finite Element

Analysis and Design Optimization of Platen for Injection Molding Machine” was

carried out by Mr. Rahul M. Thaker (Enrollment No. 130320708509) at L. J. Institute

of Engineering and Technology, (032) for partial fulfilment of M.E. Mechanical

(CAD/CAM) degree to be awarded by Gujarat Technological University. He has

complied to the comments given by the Mid Semester Thesis Reviewer to my

satisfaction.

Date:-

Place:-Ahmedabad

Rahul M. Thaker

(Enrolment No.130320708509)

Ms. Neha B. Joshi


LJIET, Ahmedabad

v

PAPER PUBLICATION CERTIFICATE

This is to certify that research work embodied in this thesis entitled “Finite Element

Analysis and Design Optimization of Platen for Injection Molding Machine” was

carried out by Mr. Rahul M. Thaker (Enrollment No. 130320708509) at L. J. Institute

of Engineering and Technology, (032) for partial fulfilment of M.E. Mechanical

(CAD/CAM) degree to be awarded by Gujarat Technological University, has been

published in International Journal of Innovative Research in science & Technology,

during May, 2015.

Date: Place:-Ahmedabad

Rahul M. Thaker


Ms. Neha B. Joshi


LJIET, Ahmedabad

Dr. A. C. Suthar

Director

LJIET, Ahmedabad

vi

THESIS APPROVAL CERTIFICATE

This is to certify that research work embodied in this entitled “Finite Element Analysis

and Design Optimization of Platen for Injection Molding Machine” was carried out

by Rahul M. Thaker (130320708509) at L. J. Institute of Engineering and Technology

is approved for award of the degree of Master of Engineering in Mechanical

(CAD/CAM) by Gujarat Technological University.

Date:

Place:

Examiner Sign and Name:

............................. .............................

( ) ( )

vii

DECLARATION OF ORGINALITY

I hereby certify that I am the sole author of this project report and that neither any

part of this nor the whole of the project report has been submitted for a degree to any

other University or Institution.

I certify that, to the best of my knowledge, my project report does not infringe

upon anyone’s copyright nor violate any proprietary rights and that any ideas,

techniques, quotations, or any other material from the work of other people included in

my project report, published or otherwise, are fully acknowledged in accordance with

the standard referencing practices. Furthermore, to the extent that I have included

copyrighted material that surpasses the bounds of fair dealing within the meaning of

the Indian Copyright Act, I certify that I have obtained a written permission from the

copyright owner(s) to include such material(s) in my project report and have included

copies of such copyright clearances to my appendix.

I declare that this is a true copy of my project report, including any final

revisions, as approved by my project report review committee.

Date:

Place: Ahmedabad

Rahul M. Thaker


Ms. Neha B. Joshi


LJIET, Ahmedabad (032)

viii

AKNOWLEDGEMENT

I express my deep gratitude and respect to my guide Ms. Neha B Joshi, Assistant

Professor in Mechanical Department, L.J.I.E.T., Ahmedabad for her valuable guidance,

motivation, cooperation, constant support with encouraging attitude at all stages of my

work. I am highly obliged to her for her constructive criticism and valuable suggestions,

which helped me to present the scientific suggestion in an efficient and effective manner

in this thesis. I thank her from bottom of my heart.

I am highly thankful to Mr. Nikunj Desai, Industrial Guide in Design

Department, Windsor India Pvt. Ltd. for his valuable guidance and proper suggestions

for solving difficulties during my work.

I would also like to thank Ms. Gayatri Pandi (Jain), Head of PG Department,

L.J.I.E.T., Ahmedabad for her constant guidance, encouragement and academic support.

I owe my most sincere gratitude to my parents whose blessing and honest support

has given me energy to start my work successfully. I admire my parents determination

and sacrifice helped me during the difficult moments of my life. Thank is a very small

words for this. Last but not the least thanks to almighty for giving me such a platform.

Rahul M. Thaker

M.E. (CAD/CAM)


ix

TABLE OF CONTENTS

Title page i

Certificate ii

Industry certificate iii

Compliance certificate iv

Paper publication certificate v

Thesis approval certificate vi

Declaration of Originality vii

Acknowledgement viii

Table of contents ix

List of figures xii

List of Table xiv

Abstract xv

Chapter 1. Introduction 1

1.1 Overview 1

1.2 Components of Plastic Injection Molding Machine 2

1.3 Injection system 4

1.4 Application of Plastic Injection Molding Machine 9

Chapter 2. Literature review 10

2.1 Review of research papers 10

2.2 Abstract of entire review 18

Chapter 3. Project work out 19

3.1 Objective of Thesis 19

3.2 Project road map 20

3.3 Various Forces act on Plastic Injection Molding Machine 21

3.4 Machine Parameters 23

3.5 Force Analysis 25

3.5.1 Calculation of Applied Pressure 25

x

3.5.2 Types of Molds mounted on Platen 27

Chapter 4. Modeling 28

4.1 Introduction 28

4.1.1 Introduction About Solid Works 28

4.1.2 Difference between solidworks and other CAD systems 28

4.1.3 Machining Drawing 29

Chapter 5. FE Analysis 30

5.1 Introduction 30

5.2 ANSYS Package 30

5.3 Analysis Results of Platen 30

5.3.1 FE Analysis of End Platen 31

5.3.2 Thermal analysis on stationary platen 36

Chapter 6. Experimental Setup and Methodology 38

6.1 Taguchi’s Philosophy 38

6.2 Taguchi Method’s Categories 39

6.2.1 Static Problems 39

6.3 Parameters Consideration For Experiment 40

6.4 Selection of Orthogonal Array (OA) 41

6.5 Variation in Parameter for Taguchi’s Design 43

6.6 Data Analysis 52

Chapter 7. Analysis and Discussion of Results 53

7.1 Testing Results 53

7.2 Analysis Software Minitab16 53

7.3 S/N Ratio Calculation for Stress And Deformation 54

7.3.1 Main Effects Plot of Stress 55

7.3.2 Main Effects Plot of Deformation 56

7.4 Analysis of Variance 57

7.4.1 Analysis of Variance for stre 58

xi

7.4.1 Analysis of Variance for deformation 59

Chapter 8. Result And Discussion 63

Chapter 9. Conclusion 64

References 65

Appendix-A:Review comment card 68

Appendix-B:Plagiarism report 73

Appendix-C:Review paper 75

Appendix-D:Published paper 80

xii

LIST OF FIGURES

Figure No. Description Page No.

1.1 Line diagram of a plastic Injection molding

machine

2

1.2 Plastic Injection Molding Machine 4

1.3 A single screw injection molding machine 4

1.4 A Reciprocating Screw 5

1.5 Nozzle with barrel 6

1.6 A typical molding system 6

1.7 A two plate mold 7

3.1 Force V/S Elongation 21

3.2 Pressure Applied at Projected Area 25

3.3 Applied forces at each strain rod 26

3.4 Pattern of Mounting a Mold 27

4.1 Stationary Platen 29

4.2 Moving Platen 29

4.3 End Platen 29

4.4 Tie Bar 29

4.5 Assembly of Platen & Tie Bar 29

5.1 Geometry of end platen 31

5.2 Mesh generation of end platen 31

5.3 Static structural analysis providing fixed support 32

5.4 Static structural analysis of platen 32




5.8 Steady state thermal analysis 36

5.9 Steady state thermal analysis 36

6.1 The Orthogonal Array Selector 41

6.2 Case-1 modeling 43

6.3 Case-1 Total Deformation 43

xiii

6.4 Case-1 Equivalent stress 43

























7.1 Screen view of MINITAB16 software 54

7.2 Effect of input parameter on Stress 55

7.3 Effect of input parameter on Deformation 56

7.4 Main effects plot for stress and deformation 60

7.5 Interaction plot for stress and deformation 61

xiv

LIST OF TABLES

Table No. Description Page No.

6.1 Range of Process Parameters 40

6.2 The Scheme of L9 Design of Experimental 42

7.1 Experimental results 53

7.2 Analysis of Variance for stress 58

7.3 Analysis of Variance for deformation 59

7.4 Analysis of Variance for stress and deformation 62

7.5 Analysis of Variance for stress and deformation 62

xv

Finite Element Analysis and Design Optimization of Platen for

Injection Molding Machine

By

Rahul M. Thaker

(Enrolment No. 130320708509)

Gudied By

Ms. Neha B. Joshi

Assistant professor, Mech. Engg.

Dept. LJIET, Ahmedabad

ABSTRACT

Plastics are certainly most versatile of all known materials today and have

therefore, established themselves in enviable position from where are not even possible to

replaced. Injection molding machine is one of the most widely used method of

conversion of plastic into various end products application to wide range of plastic

materials from plastic commodity to specialty engineering plastic. In injection molding

machine platen play a very important role. During the process generally compressive

stress generates at particular regions. As load varies with fast rate there is chance to

failure of tie bar rod. Due to heavy mould shape, size of platen also change, that’s

increase its weight as well as stress level at certain region and this is not good in practice.

This leads to failure of platen or failure of tie rod due to stretching by nut and platen. The

aim of this research is study about those areas where stress can affect the failure of tie bar

due to heavy weight of platen the deflection or misalignment with movable platen.

Finally redistribution of stress so that uniform stress achieve (optimization of platen).

This project is including Finite Element Analysis and Optimization of a Typical

Structural Component of a Plastic Injection Molding Machine. The aim of project is to

optimize a typical structural component (platen) by using finite element analysis after

checking induced stresses with allowable design stress. Optimize design of platen with

the use of removing material from them. Hence design modification of platen is carried

out to achieve good strength and cost effectiveness.

1

CHAPTER-1

INTRODUCTION

1.1 Plastic Injection Molding Machine Overview

Plastics are certainly the most versatile of all known material today and have, therefore,

established themselves in an enviable position from where they are not even possible to

be displaced.

The most common method of conversion of plastics are: -

Compression Molding

Injection Molding

Blow Molding

Extrusion And Thermoforming

Injection molding is one of the principle methods of conversions of plastics into various

end-products using a very wide range of plastics materials from commodity plastics to

specialty engineering plastics.

A large variety of molding machines are manufacture in the country with the

indigenously developed technology as well as in collaboration with the world leaders to

indigenously manufacture machines of world standards. Clamping force, low pressure

molding machines, gas injection molding machines, multi component molding

machines‟s co-injection molding machines or some very special tailor-made machines

dedicated to specific end-uses and polymers.

The facilities for mold making have also developed over the years and even the most

difficult and sophisticated molds are now being designed and fabricated in India. The

potential for the injection molded products is tremendous in our country.

2

Courtesy: www.plasticsdome.com

Fig 1.1 Line diagram of a Injection molding machine[21]

1.2 Components of Plastic Injection Molding Machine:

1.2.1 Types of Machine

These are broadly classified as plunger and screw types.

1.2.1.1 Single-Stage Plunger

The forward motion of plunger forces the granules along the cylinder around spreader.

The section of injection cylinder around the spreader is heated by electrical heaters and

the materials is spread so thin in passing between spreader and cylinder that is melted to

the point where it can be forced through the nozzle in the clamping action of pres plates

and the plastic material is forced into all area of cavities.

3

1.2.1.2 Two-Stage Plunger Machine

This equipment involves two plungers, one on top of the other. One plasticizes the

material and feeds it to the other cylinder where the second one, which is stronger,

operates as shooting plunger and pushes plasticized materials into the mould.

1.2.1.3 Two-Stage Screw Plunger Machine

Here the action of screw serves to work and melt the resin and feed it to the second

plunger unit, where the injection ram forces it forward into the mould.

1.2.1.4 Reciprocating Screw Type Machine

In this machine the plunger/spreader has is a key to the plunger type machine, is replaced

by a reciprocating screw, which moves back and forth within the heating cylinder. As the

screw rotates, the flights pick up the feed of granular material from the hopper and force

it along the hot cylinder barrel.

The complete cycle can be depicted as under: -

1. Oil is set behind the clamp ram closing the mould. Pressure builds up to develop enough

force to keep mould closed while the injection process occurs.

2. Previously plasticized material, in front of reciprocating screw, is forced into the mould

by the hydraulic injection cylinders.

3. Pressure is maintained on the material to mould a part free from sink marks, flow marks,

welds and other defects.

4. At the end of this period, the screw starts to turn plasticizing material for next shot.

5. While this is occurring, the plastic is cooling in the mould and solidifying to a point

whereby it can be ejected successfully. This cooling is accomplished by circulating a

cooling media, usually water, through drilled holes or channels in mould base, cavities

and cores.

6. Oil is sent to return port of clamping ram, separating the mould halves.

7. As moving platen returns, the knock-out or ejection mechanism is activated removing

pieces from the mould.

4

Fig 1.2 Plastic Injection Molding Machine [21]

1.3 Injection system

The injection system consists of a hopper, a reciprocating screw and barrel assembly, and

an injection nozzle, as shown in Fig 1.4. This system confinesand transports the plastic as

it progresses through the feeding, compressing, degassing, melting, injection, and

packing stages.

Fig. 1.3 single screw injection molding machine[22]

Hopper

Thermoplastic material is supplied to molders in the form of small pellets. The hopper on

the injection molding machine holds these pellets. The pellets are gravity-fed from the

hopper through the hopper throat into the barrel and screw assembly.

5

Barrel

As shown in Fig 1.4, the barrel of the injection molding machine supportsthe

reciprocating plasticizing screw. It is heated by the electric heater bands.

The Reciprocating Screw

The reciprocating screw shown in Fig 1.5 is used to compress, melt, andconvey the

material. The reciprocating screw consists of three zones:

feeding zone

compressing zone

metering zone

When outside diameter of the screw remains constant, the depthof the flights on the

reciprocating screw decrease from the feed zone to the beginning of the metering zone.

These flights compress the material gainst the inside diameter of the barrel, which creates

viscous (shear) heat.This shear heat is mainly responsible for melting the material. The

heater bands outside the barrel help maintain the material in the molten state.

Fig 1.4 Reciprocating screw‟s feeding zone, compressing (or transition) zone, and metering zone.

[22]

The nozzle

The nozzle connects the barrel to the bushing of the mold and formsa seal between the

barrel and the mold. The temperature of the nozzle should be set to the material's melt

temperature or just below it, depending on the recommendation of the material supplier.

When the barrel is in itsfull forward processing position, the radius of the nozzle should

6

nest and seal in the concave radius in the sprue bushing with a locating ring. During

purging of the barrel, the barrel backs out from the sprue, so the purging compound cans

free fall from the nozzle. These two barrel positions are illustrated in Fig 1.6.

Fig.1.5 (a) Nozzle with barrel in processing position. (b) Nozzle with barrel backed out for purging.

[22]

Mold system

The mold system consists of tie bars, stationary and moving platens, as well as molding

plates (bases) that house the cavity, sprue and runner systems, ejector pins, and cooling

channels, as shown in Fig 1.7.The mold is essentially a heat exchanger in which the

molten thermoplastic solidifies to the desired shape and dimensional details defined by

the cavity.

Fig.1.6 A typical molding system[22]

A mold system is an assembly of platens and molding plates typically made of tool steel.

The mold system shapes the plastics inside the mold cavity (or matrix of cavities) and

ejects the molded parts. The stationary platen is attached to the barrel side of the machine

and is connected to the moving platen by the tie bars. The cavity plate is generally

7

mounted on the stationary platen and houses the injection nozzle. The core plate moves

with the moving platen guided by the tie bars. Occasionally, the cavity plate is mounted

to the moving platen and the core plate and a hydraulic knock-out (ejector) system is

mounted to the stationary platen.

Two-plate mold

The vast majority of molds consist essentially of two halves, as shown in Fig 1.7. This

kind of mold is used for parts that are typically gated on or around their edge, with the

runner in the same mold plate as the cavity.

Fig.1.7 A two plate mold[22]

Cooling channels (circuits)

Cooling channels are passageways located within the body of a mold, through which a

cooling medium (typically water, steam, or oil) circulates. Their function is the regulation

of temperature on the mold surface. Cooling channels can also be combined with other

temperature control devices, like bafflers, bubblers, and thermal pins or heat pipes.

Hydraulic system

The hydraulic system on the injection molding machine provides the power to open and

close the mold, build and hold the clamping tonnage, turn the reciprocating screw, drive

the reciprocating screw, and energize ejector pins and moving mold cores. A number of

hydraulic components are required to provide these powers, which include pumps,

valves, hydraulic motors, hydraulic fittings, hydraulic tubing, and hydraulic reservoirs.

8

Control system

The control system provides consistency and repeatability in machine operation. It

monitors and controls the processing parameters, including the temperature, pressure,

injection speed, screw speed and position, and hydraulic position. The process control has

a direct impact on the final part quality and the economics of the process. Process control

systems can range from a simple relay on/off control to an extremely sophisticated

microprocessor-based, closed-loop control.

Clamping system

The clamping system opens and closes the mold, supports and carries the constituent

parts of the mold, and generates sufficient force to prevent the mold from opening.

Clamping force can be generated by a mechanical (toggle) lock, hydraulic lock, or a

combination of the two basic types.

Cold runners

After molding, the cold-runner delivery system is trimmed off and recycled. Therefore,

the delivery system is normally designed to consume minimum material, while

maintaining the function of delivering molten plastic to the cavity in a desirable pattern.

Hot runners

The hot-runner (or runner less) molding process keeps the runners hot in order to

maintain the plastic in a molten state at all times. Since the hot runner system is not

removed from the mold with the molded part, it saves material and eliminates the

secondary trimming process.

9

1.4 Application of Plastic Injection Molding Machine:

In Automobile application like Radiator Fan, Air Separator.

In engineering application like Pipe End Cap, Pipe Coupler, Textile Bobbin.

Computers & Accessories: Mouse, Key Board Parts.

Electrical & Electronics: 2 point socket, Miracle Base.

Furniture: Back chair with arm.

Food / Non Food Containers: Plastic Container, Round Container.

Medical / Lab: Measuring Cup, Lab Tray.

Writing Instruments / Stationeries: Pen Barrel, Scale.

Automotive Structural Parts.

TV Cabinets.

Computer Monitor-housing.

Rigid Packaging Containers.

10

CHAPTER-2

LITRETURE REVIEW

2.1 REVIEW OF RESEARCH PAPERS

C.Sasikumar, S.Srikanth, S.K.Das (January-2006)[1]

“Analysis of premature failure of a tie bar in an injection molding machine”

In this paper researcher, the tie bars are subjected to a pulsating cyclic loading during the plastic

molding process. The failure was occur at the root of the first thread of transverse fatigue

fracture induced by a pulsating tensile stress with multiple points of high stress concentration.

The high stress concentrations appear to have introduced with a combination of improper

molding parameters resulting in uneven tensions in the four tie bars and aggravated by the

presence of some material defects. The material defects observed are inclusions, presence of

some retained austenite and fine cracks. The tie bar of the injection-molding machine has failed

at the root of the thread by fatigue fracture induced in a combination of pulsating cyclic tensile

stress and a component of torsional stress with multiple points of high stress concentration. High

stress concentrations have introduced with a combination of improper molding parameters

resulting in uneven tensions in the four tie bars and significant amount of material defects.The

fatigue crack has initiated at the root of the final thread at an inclusion and propagated through

the inclusions and fine cracks inherently present in the material. Once the diameter of the tie bar

is reduced due to the propagation of fatigue fracture and reaches the critical diameter, the final

failure has occurred by ductile fracture due to overload.

Z.W.jiao,P.C.Xie, Y.An,X.T.Wang, W.M.Yang ( June-2011)[2]

“Development of internal circulation two-platen IMM for Thermoplastic Polymer”

In this research proposed and designed an internal circulation two-platen IMM, which can

produce plastic parts while maintaining excellent quality. Experimental tests performed on the

IMM prototype CHH200 (results of which were compared with a toggle IMM of the same

11

specification) show that the clamping force partial load rate and clamping force repeatability of

CHH200 are higher than those of the toggle IMM. Items produced by IMM CHH200 are shown

to be more precise, with weight repeatability reaching 0.867%. and a low energy consumption of

0.395 kWh/kg. Utilizing the IMM, ultra-precise plastics parts used in automobiles, IT,

medicines, and many other products can be molded with lower equipment cost and power cost.

Energy consumption for the internal circulation two-platen IMM is below 0.4 kWh/kg. The

structure of the internal circulation two-platen IMM‟s simple, with the CHH200‟s number of

parts being 46 less than that of a toggle machine‟s of the same specification. The internal

circulation two-platen clamping unit can achieve strong mold adaptability. Weight repeatability

for the CHH200 can reach as low as 0.867%.

George Z. Voyiadjis, PawelWoelke (august-2005)[3]

“General non-linear finite element analysis of thick plates and shells”

In this paper researcher presented a non-linear FE analysis, for the elasto-plastic behavior of

thick shells and plates including the effect of large rotations. In the treatment of material non-

linearities the authors adopt:

I. A non-layered approach and a plastic node method.

II. A yield function expressed in terms of stress resultants and stress couples modified to

investigate the development of plastic deformations across the thickness, as well as the

influence of the transverse shear forces on plastic behavior of plates and shells.

III. Isotropic and kinematic hardening rules.

Hence, Non-linear finite element analysis had used for assembly analysis to analyze the exact

values of stress and deflection at the moving platen because there is a bonded contact between

the mating components of assembly, therefore there will be a non-linear behavior of the analysis.

Patel Niral ,MihirChauhan ( March-2013)[4]

“FEA and Topology Optimization of 1000T Clamp Cylinder for Injection Molding

Machine”

12

The paper consist the detail design of clamp cylinder for 1000 ton injection machine with

topology optimization. The design is carried out based on calculated diameter and thickness.

Modeling and FEA is doing for newly designed 1000T clamp cylinder and to be verified with

theoretical calculation and acceptance criteria. The topology optimization of clamp cylinder is

also carried out using CAE tools to reduce weight with the constraints of standard operating

condition. Topology optimization is a mathematical approach which optimizes the material

layout within a given design space, under given set of loading and boundary condition. Fourteen

iterations were required to solve this the optimization problem. The optimized model is equally

strong and light in weight compared to existing model. After modify the topology of the clamp

cylinder the maximum principle stresses and the total deformation within the permissible limits,

but substantial reduction of the material hence weight have been obtained. Hence the purpose of

the topology optimization serves. The topology optimization of the component is carried out and

substantial reduction in weight about 70 kg is obtained.

DheerajMandliya, YogeshAgrawal, G.V.R SeshagiriRao (May-2014)[5]

“Design Optimization of Stationary Platen of Plastic Injection Molding Machine Using

FEA”

In this paper researcher to study about those areas where stress can affect the failure of tie bar

due to heavy weight of stationary platen the deflection or misalignment with movable platen.

During the process generally compressive stress generates at particular regions. As load varies

with fast rate there is chance to failure of tie bar rod. Due to heavy mould shape, sizes of platen

also change, that‟s increase its weight as well as stress level at certain region and this is not good

in practice. This leads to failure of platen or failure of tie rod due to stretching by nut and platen.

This paper is including Finite Element Analysis and Design Optimization of a Typical Structural

Component of a Plastic Injection Molding Machine. The aim of paper is to optimize a typical

structural component (stationary platen) by using finite element analysis after checking induced

stresses with allowable design stress. FE analysis of existing stationary platen is carried out by

using ANSYS software. Finally In optimization design modification has been carried out in

Pro/E model and checked for its feasibility with respect to stresses and weight. The aim of the

optimization is reduce the weight and make it cost effective. Existing model of stationary platen

13

has dome type shape. Dome type shape is converted in to box type which resulted in reduction of

overall thickness of platen to the tune of 5 %.

Shu Huang Sun (Septmber-2004)[6]

“Optimum topology design for the stationary platen of a plastic injection machine”

In this paper researcher main objective is to design the structure of the stationary platen with

optimized stiffness at minimal raw material cost. Tie bars are key components of a plastic

injection machine. They very easily fatigue in periodically long term operations due to the

bending moment transferred to them by the bending of the stationary platen. This problem can be

easily overcome by reducing the deflection of the stationary platen through topology

optimization of the platen structure by applying a cost or weight constraint. In this paper, the

self-organization method was introduced to optimize the topology of the stationary platen. This

method is to modify the Young‟s modulus of each element according to the ratio of its stress and

the average stress of the entire model after each FEM analysis. By applying this method to the

stationary platen design, the deflection of the platen could be reduced, which correspondingly

reduces the bending load of the tie bars and thus extending their operating life. The proposed

stationary platen design was almost identical to that used in a commercial machine Also, the

proposed method herein, proved the effectiveness of the existing platen design through a simple

and systematic scientific way.

Mold Flow Corporation, USA (s2005)[7]

“Simulation of core shift and Injection Molding Machine clamp over-tonnage using

Mold-flow plastics”

In this paper researcher said, when the clamp force of the machine is exceeded to the limit, the

tie bars stretch. The mold will open the amount of the stretch, increasing the wall thickness of the

part. As the part shrinks, the clamp force is reduced and the mold will shut. In most molds, the

pressure distribution is not even, so the stretching of the tie-bars is not uniform. The ends of the

tie-bars that are not attached to the platen have a displacement load applied to them which

14

represent the stretch applied to the tie-bars based on the clamp force applied to the mold.This is

calculated based on the following relationship: -

Clamp force ∗ (length of the tie bars )

(Modulus E of the tie bars) ∗ (total transverse area of the tie bars)

The total amount of the bending of the moving platen and elongation of the Tie-bars depend

upon the maximum camping force applied by the machine.

D. Papageorgiou, C. Medrea , N. Kyriakou( march 2013)[8]

“Failure analysis of H13 working die used in plastic injection moulding”

This paper is focused on the failure of a die used in plastic injection molding. The die was made

from AISI H13 steel and was intended for the production of plastic cups used for the outer

closure of cylindrical aluminum cans in coffee packaging. Extended corrosion damage on

various areas of the metallic part and a wide crack can be observed by the naked eye. The design

deficiency and improper cooling conditions generated a complex fatigue-corrosion cracking

mechanism that lead to the damage of the die after half of its predicted service life. Poor design

and improper cooling agent are responsible for the die failure. The water corroded the cooling

surface leading to increased surface roughness. The surface irregularities converted the laminar

liquid flow into turbulence. Corroded crack tip worsens the stress contribution around it and

accelerates crack propagation. The crack propagated towards the mould-surface and ended at the

injection hole. The most effective method to prevent similar failures is the reduction of the stress

contribution. Furthermore, the intensive corrosion could have been avoided by using salt-free

cooling water. In addition, selection of corrosion fatigue resistant steels is desirable.

Ph.D. Eng. VolodymyrKrasinskiy(2012)[9]

“Optimization of Injection Molding Manufacturing For Automotive Industry”

This paper deals with optimization of injection molding process. Optimization of process with

configuration of main parameters influences on velocity of injection cycle, quality of moulds and

15

energy consumption. The aim is to reduce the time of the injection process and reduce the

number of defective parts during mass production. Examination analyzing injection molding

production process and optimize the manufacturing process using software. The task of the

optimization was to create moldings with required quality in the shorter injection cycle, without

compromising their quality. The simulation included a test of process parameters obtained during

the optimization of injection molding process. Fill analysis of the cavity and injection pressure

analysis revealed the cause of burns in two places between inlet moldings. Analysis of quality

prediction revealed the possible problems during production and confirms problems from praxis.

Optimization of the injection cycle and error analysis yielded shortens production cycle and

reduced the proportion of waste during production because of visual defects. Thus optimization

of this part and process saves the energy and material costs.

Li-ping Ding, Jian-rong Tan, ZheWei(January-2010)[10]

“Multi-Objective Performance Design Of Injection Molding Machine Via A New Multi-

Objective Optimization Algorithm”

To solve the multi-objective optimization problem of injection molding machine product's

overall performance, the optimal design of injection molding machine is studied and the design

problem is formulated as a constrained multi-objective problem involving continuous and

discrete design variables. Furthermore, with the K means of joint support vector clustering

method to reduce the number of external stocks, a new multi-objective optimization algorithm

KSVC-SPEA is proposed. Then, taking the multi-objective optimization of the overall

performance of the HT160X1N high-speed injection molding machine as an example, the

traditional linear weighting methods, Strength Pareto Evolutionary Algorithm (SPEA) and the

KSCV-SPEA are applied. The traditional linear weighting method and the KSCV-SPEA are

applied to the optimization design problem of the HT160X1N injection molding machine's

overall performance respectively. The optimization results show that the Pareto frontier achieved

by the KSCV-SPEA has better border and distribution. In addition, through the computations of

the cases with external population at different scales, it can be noticed that the KSVC clustering

method can effectively improve the performance of clustering operations of the large scale

population, meaning the computing efficiency are improved signicantly.

16

Xiaowei Li, Zhiming Jin, Yajun Zhang[11]

“Kinematic calculation analysis of micro injection molding machine with double-toggle

clamping mechanism based on MATLAB”

The geometric model of micro injection molding machine with double-toggle clamping

mechanism is established to analyses the kinematic and mechanical performance of double

toggle clamping mechanism. The kinematic analysis of the double-toggle clamping mechanism

is used to study the effects of the double-toggle parameters for the microstructure injection

molding machine. The parameters discussed in this paper include the amplification ratio, velocity

ratio and the amplified force ratio for the double-toggle clamping mechanism. The optimized

parameters of clamping mechanism are obtained according the calculation results of stroke ratio,

velocity ratio and the amplified force ratio. This paper is based on the geometric model of

double-toggle clamping mechanism. After analyzing the mechanical and kinematic performance

of the mechanism specially, the mathematic expression of geometry and position dimensions,

stroke, velocity and force amplified ratio, which settles theoretic foundation for the calculation

analysis of MATLAB.

Amol J. Asalekar(sept-2014)[12]

“Design & Analysis in Injection Moulding Machine System to Reduce the Torsional

Failure of Screw”

The plastic being melted in injection molding machine and then injected into the mould. The

barrel contains reciprocating screw for injecting the material into the mould and the material is

also melted into the barrel. This project deals with, the solution of problem occurred for

reciprocating screw of Injection molding machine. It identifies and solves the problem by using

the modeling and analysis techniques. The problem occurred in the reciprocating screw of

machine which is wearing of threads due to effect of temperature of mold materials. The main

work was to model the components of machine with dimensions, and perform static and thermal

analysis with parts of injection molding machine parts like reciprocating screw. In analysis of

coupling we can observe that, coupling shows maximum possibility of failure than reciprocating

screw. And maximum value of equivalent stress is obtained is also to much higher than

17

reciprocating screw . We can say from analysis of coupling and reciprocating screw, coupling is

weaker one than reciprocating screw and it will really fail before. The coupling is the better

solution for reducing at least torsion failure of the reciprocating screw by making coupling

element than reciprocating screw in injection molding process

Mr.G.V.Pujari (January-2015)[13]

Defect by Applying Taguchi & Moldflow Method For Injection Molding Component

This paper describes about the parameter optimization using the combination of design of

experiment (DOE) Taguchi method and Moldflow simulation tests by this method, it can gain

the experiment data which can reflect the overall situation using fewer number of simulation test.

Furthermore, the effects degree of different molding process parameters for surface sink marks

are investigated, optimized parameter combination is obtained. It can solve the unreasonable

appearance of process parameter settings. The mold design above mentioned can fasten the mold

developing schedule, thus shorten the cycle of product development, and improve the quality of

products and the competitive ability of enterprise. The simulation considering the sequence of

effects degree of different molding process parameters for surface sink marks ranked in the

holding pressure; melt temperature, cooling time and injection pressure. The holding pressure is

the most important effect. The optimized parameter combinations of different factors are

considered as melt temp 235°c; injection pressure 80 bar; holding pressure 55 bar & cooling time

50 sec, and its sink marks index is 2.674, which is the best data compared with other parameter

combinations.

18

2.2 ABSTRACT OF ENTIRE REVIEW:

In general, the researchers give different method of topology optimization and FE

analysis of injection molding machine by changing its geometry. One of the researchers Shu

Huang Sun From Kun Shan University Of Technology, Taiwan has research on topology design

for the stationary platen of a plastic injection machine. He had carried out on ANSYS 5.5 to

FEM analysis for stationary platen.

Following are the some points which shows the entire review of the above research‟s papers:

Researchers outlined modification of platen is carried out to achieve good strength and

cost effectiveness.

Some researchers focus on failure analysis in tie bar & reduce the bending load of tie

bars. So its increase operating life of platen.

Some researchers focus on failure of Screw, Multi-Objective Optimization Algorithm is

for optimization.

As per review of research papers, we can see that during the process compressive stress

generates at particular regions of platen. As load varies with fast rate there is chance to failure of

tie bar rod. Due to heavy mould shape, sizes of platen also change, that‟s increase its weight as

well as stress level at certain region. This leads to failure of platen or failure of tie rod due to

stretching by nut and platen. Main objective of these literature study are, optimize design of

platen with the use of removing material from them.

19

CHAPTER-3

PROJECT WORK OUT

3.1 OBJECTIVE OF PROJECT WORK:

The aim of this project is study about those areas where stress can affect the failure of tie bar

due to heavy weight of stationary platen the deflection or misalignment with movable platen.

Finally redistribution of stress so that uniform stress can achieve (optimization of platen) and

optimize design of platen with the use of removing material from them.

The objectives of the study are as follows:-To reduce weight of clamping assembly. To

reduce weight of moving platen. To reduce running cost of machine.

In injection molding machine platen play a very important role. During the process generally

compressive stress generates at particular regions. When load varies with fast rate there is

chance to failure of tie bar rod. Due to heavy mould shape, size of platen also change, that‟s

increase its weight as well as stress level at certain region.

20

3.2 PROJECT ROAD MAP:

FE ANALYSIS OF STRUCTURAL

COMPONENT BY USING ANSYS

TO SHORT OUT THE

PROBLEMS RELATED STRUCTURAL

COMPONENT OF

INJECTION MOLDING MACHINE.

VALIDATION OF RESULTS

LITERATURE REVIEW

ABOUT INJECTION

MOLDING MACHINE .

OPTIMIZATION OF PLATEN

BY DOING DESIGN OF

EXPRIMENT

PROJECT START

PROJECT END

TO PREPARE 3D MODEL OF

STRUCTURAL COMPONENT

OF INJECTION MOLDING

MACHINE.

FE ANALYSIS OF OPTIMIZED

PLATEN BY USING ANSYS

RESULTS OF OPTIMIZED

PLATEN

21

3.3 VARIOUS FORCES THAT ACT ON PLASTIC INJECTION MOLDING

MACHINE:

The Various Forces Which Act On The Machine Are Following: -

Clamping force

Reactive force (due to cavity pressure)

Total force (clamping + reactive)

Breaking force

Ejection force

The maximum clamping force is reached when the toggle links are fully extended and

straightened in their end position. This force fc

is built up in accordance with the spring

characteristics of the tie-bars. It is attained when closing and locking are completed and is

equal to the sum of all tensile forces in the tie bars. The maximum clamping force fc max

is

the maximum force a machine can produce.

The maximum clamping force fc max

produces a method of the tie-bars of the magnitude

atb max

. The force-deformation diagram generated by a machine with a mechanical clamp

system, such as toggle clamp is shown in following:

Fig.3.1 Force V/S Elongation[23]

22

Fc max – Maximum clamping Force

Atb max - Magnitude of Tie bar

FR – Relative force

Ax – Distance

The clamping force Fc Max

affects the mold and compresses it by the distance AmoMax

.

During injection into the mold cavity, a reactive force FR

is produced, which is the

product of the average cavity pressure multiplied by the cavity area projected on a plane

through the parting line. This force decreases the compression of the mold AMO

and

increases the elongation of tie-bars ATB

. As soon as flashing occurs, this action has

reached its practical limit somewhere between FO

= FR MAX

& FO

= FR PERM

. During this

action, the elongation of the tie-bars increases first to ATB MAX

. This cause the mating

mold surfaces to separate by a distance AX. The permissible value of a

x depends on the

plastic material and on the melt and mold temperatures. It is of order of 0.05-0.1mm. The

usable force reserve of a toggle clamp system is if the magnitude of 10% of the clamping

force.

The rigid unit permits a higher Total Clamping Force (Reactive Force) before the mold

halves begin to separate. At this moment, the stresses in the tie bars are higher than in the

less rigid unit. Thus, one can conclude that rigid bars call for a greater safety factor than

yielding (thin) ones, if they are frequently over-loaded by incorrect operation (equal flash

in both cases). Reproducibility and precise adjustment of the clamp force certainly not

improved with an extremely rigid design, because the force is produced within a

relatively small distance and subject to great variations.

To set the desired Clamping Force, a suitable distance between mold platen and tail

stock platen is selected and adjusted with mostly a central mechanical adjusting device.

Another critical point is the deflection of the machine platens, primarily the stationary

platen. For reasons of strength, little thickness is sufficient most of the time. An

acceptable value would be a deflection of <0.2 mm related to 1 m distance between tie

23

bars. The problem of deflecting machine platens, of course, also exists in machines with

hydraulic clamping units.

The Opening Force is the force produced by the clamping unit during the opening stage.

The forces available over the full stroke are smaller during opening than during closing.

The nominal opening force is that force which remains attainable for opening the mold

after clamping and subsequent unlocking.

The Toggle Forces are fully sufficient to break open the mold. Ejection is often produced

during mold opening by an ejector bar, against which the movable platen moves and

which activates the ejection system of the mold. The magnitude of the ejection force

which is exerted upon the ejection system in the mold is important. This operation uses

the opening force of the toggle which is available after part of the opening stroke has

been completed. It cannot be more than the minimum opening force which is only 1 to

2% of the maximum clamping force in the most adverse case.

3.4 Machine Parameters:

Screw Travel:

Most machines have a pointer attached to the injecting screw and a stationary scale to

indicate the distance of the injection stroke. If it is desired to convert the weight of a shot

in grams into inches of screw travel, it can be done below: -

In3 =gms

sp. Gravity x 16.39

The distance of travel can be calculated as: -

distance of travel for material at hand =In3 of material x screw travel

In3 of metering section

For a great many materials the 2 ton/in2

is adequate. For polycarbonate, however the

value is 5 and for nylon, 7 ton/in2

.

24

Machine Capacity:

As it relates to shot size means how many ozs/gms of polystyrene can be plasticized per

second divided. The number of ozs/gms of ps plasticized per second divided into the

number of ozs/gms of machine capacity will provide an estimated time that a full shot of

ps will take. thus if the plasticizing capacity is 100kg/hour,

100kgs. = 278g/sec,

3600

so, say a shot of 500gms will require,

500g = 1.79 seconds, to plasticize the full shot of ps.

278

Molding Set-Up Time

Molding Set-Up Time (Seconds) = Factor X Max Thickness (cm2

)

Cylinder Temperature: Colors

It is often observed that the cylinder temperatures are required to be re-set for the same

polymer, for the same product, when the color is changed. In general, white, blues, greens

require a slightly higher setting than red, brown and black.

Mold Connections for Water

Mold temperature connections should be placed away from the operator side and recessed

wherever possible so that the damage is eliminated. Whenever quick disconnect

couplings are used, care should be taken to see that the openings in the timings will not

restrict the flow to the mold and to ensure that the proper velocity for turbulent flow is

maintained.

Clamp Tonnage and Mold Size

Most platens are made of cast steel with yield strength of about 25tons/in2

allowing a

factor of safety of 7 the permissible load could be 3.5tons/in2

with this data, the minimum

area, in2

a certain machine will safely bear or what reduction in tonnage of the clamping

force required to protect the platens from damage could be worked out.

25

Clamping Force

This is usually expressed in ton and if this is not adequate, the two halves of the mold

will open because of force exerted by the melt injected into the mold.

The relationship is 𝑓 =p x a

2000

Where,

F = force (tons),

P = pressure (psi, average 10,000)

A = projected area, in2

.

3.5 Force Analysis:

Forces Applied on Stationary Plate

All pressure from the mold side transferring to the stationary platen.

Then these forces transferring to strain rod through stationary platen.

And the forces from the strain rod transfers to the NUT.

Nut is fixed so it produced the reaction forces.

3.5.1 Calculation Of Applied Pressure:

Max. mold area= l*b

Min. mold area= k1l * k2b

K1= k2= 0.67= constant

Force= 160 ton

Pressure= 1655 bar = 165.5 N/mm2

Fig.3.2 Pressure Applied at Projected Area

26

Area =𝑓𝑜𝑟𝑐𝑒

𝑝𝑟𝑒𝑠𝑠𝑢𝑟𝑒 = 9483.98 mm

2

Fig.3.3 Applied forces at each strain rod

Force applied due to each strain rod = 𝑓𝑜𝑟𝑐𝑒

4

= 160∗1000∗9.81

4

= 392400 N

Bending stress :

Maximum bending stress:σ = β W/ t2

β= bending constant = 1.115

W= total load apply = 160 ton

T = thickness of plate = 220 mm

Put all values in above equation

So we get value of σ = 36.15 N / mm2

NOTE:

Design of stationary platen in such a way that the all forces transferred to stationary

platen are equally and opposite in nature.

If the forces applied to the stationary platen are equally distributed then the

symmetrical bending and stretching of tie rod equally.

27

So we can maintain relative deflection within some criteria otherwise there are

following problem arise.

1. Mold Flash

2. Distortion of Mold

3.5.2 Types of Molds mounted on Platen:

Fig.3.4 Pattern of Mounting a Mold[22]

28

CHAPTER - 4

MODELLING

4.1 INTRODUCTION

The modeling has been performed on the Solid works 2013 version and then after the

analysis work has been performed on the ANSYS 12.1 version.

4.1.1 About Solid works

Solid works is a computer graphics system for modeling various mechanical designs

for performing related design and manufacturing operations. The system uses a 3D

solid modeling system as the core, and applies the feature base parametric modeling

method. In short solidworks is a feature based parametric solid modeling system with

many extended design and manufacturing applications.

4.1.2 Difference between Solidworks and other CAD systems:

Solidworks is the first commercial CAD system entirely based upon the feature based

design and parametric modeling philosophy. Today many software producers have

recognized the advantage of this approach and started to shift their product on to this

platform. Nevertheless, the differences between a feature based, parametric solid

modeling.

Solidworks Conventional CAD systems

Solid model Wire frame and solid model

Parametric model Fixed-dimension model

Feature based modeling Primitive-based modeling

Subject oriented sub-modeling systems A single geometry based system

29

4.1.3 MACHINING DRAWING FOR PLATEN:

Fig. 4.1 Stationary Platen

Fig. 4.3 Moving Platen

Fig. 4.2 End Platen

Fig. 4.4 Tie Bar

Fig. 4.5Assembly of Platen & Tie Bar

30

CHAPTER - 5

FE ANALYSIS

5.1 Introduction

The ANSYS-12.1 software is used to obtain the results by FEM. The modeling, meshing

and post-processing are done by the ANSYS the results obtained will be compared with

the results of analytical solutions.

5.2 ANSYS Package

The ANSYS is a comprehensive general-purpose finite element computer program. The

ANSYS program has many capabilities ranging from a simple, linear, static analysis to a

complex, nonlinear, transient dynamic analysis. A typical analysis in ANSYS involves

three distinct steps.

1. Pre-processing: Using PREP7 processor, providing data such as the geometry,

materials, and element type to the program.

2. Solution: Using Solution processor, defining the type of analysis, set boundary

conditions, applies loads, and initiate finite element solutions.

3. Post processing: Using POST1 (for static or steady state problems) or POST26 (for

transient problems), reviewing the results of analysis through graphical displays and

tabular listings.

5.3 Analysis Results of Platen:

Static FE analysis has been carried out on Platen for checking stress and weight. Here

shown in figure four faces of hole are fixed and force 160 ton applied on toggle part.

Then automatic tetrahedral mesh generation generate nodes-42252, element-160862.

The below fig show geometry of end platen and then generate mesh on it.

31

5.3.1 FE Analysis of End Platen

Fig.5.1 geometry of end platen

Fig.5.2 mesh generation of end platen

32

Fig.5.3 static structural analysis providing fixed support

Fig.5.4 static structural analysis of platen

33



34


The above fig. Show that static structural analysis of end platen.

First take fixed support and then apply force 160 ton on that platen. Then analysis carried

out on equivalent (von-mises) stress.

Here shows that toggle link get maximum shear stress. And total deformation has been

carried out it like 0.1834 mm.

Material properties: Materials in the Workbench are imported from material library

available in ANSYS database.

35

Test Report

Result of standard model from test report:

Generated Stress: 181.62 MPa

Total Deformation: 0.1965mm

36

5.2.3 Thermal analysis on stationary platen

Fig.5.8 steady state thermal analysis

Fig.5.9 steady state thermal analysis

37

The above Fig shows that steady state thermal analysis on stationary platen.

In stationary platen nozzle has mounted on center for injection for mold in clamping unit.

In thermal analysis carried out on center of platen. Nozzle get hot in injection unit so, this

temperature may effect on stationary platen and it get deformed. Hear temperature apply

on center of platen for analysis of thermal effect.

Total deformation δl = α*l*δt

Where δl = total deformation

α = coefficient of thermal expansion= constant

δt = (tmax– tmin)

put all value on above equation.

So, Total deformation δl = 0.0747 mm

Hence , it very low value and can be negligible.

38

CHAPTER -6

EXPERIMENTAL SETUP AND METHODOLOGY

DESIGN OF EXPERIMENT

In this study, three machining parameters were selected as control factors, and each

parameter was designed to have three levels, denoted 1, 2, 3 and 4 (Table). The experimental

design was according to an L‟9 array based on TAGUCHI Method, while using the Orthogonal

array would markedly reduce the number of experiments. A set of experiments designed using

the TAGUCHI method was conducted to investigate the relation between the process parameters

and response factor. Minitab 16 software is used to optimization and graphical analysis of

obtained data.

Topology optimization is a powerful structural optimization method that combines a

numerical solution method, usually the finite element method, with an optimization algorithm to

find the optimal material distribution inside a given domain. In designing the topology of a

structure we determine which points in the domain should be material and which points should

be void.

6.1 TAGUCHI’S PHILOSOPHY

Design of experiment (doe) is a powerful statistical technique for improving

product/process designs and solving production problems. A standardized version of the doe, as

forwarded by Dr. Genichi Taguchi, allows one to easily learn and apply the technique product

design optimization and production problem investigation. There are a number of statistical

techniques available for engineering and scientific studies. Taguchi has prescribed a standardized

way to utilize the Design of Experiments (DOE) technique to enhance the quality of products

and processes.

Upstream methods efficiently use small-scale experiments to reduce variability and

remain cost-effective, and robust designs for large-scale production and market place. Shop-floor

techniques provide cost-based, real time methods for monitoring and maintaining quality in

production. The farther upstream a quality method is applied, the greater leverages it produces on

39

the improvement, and the more it reduces the cost and time. Taguchi„s philosophy is founded on

the following three very simple and fundamental concepts:

Quality is best achieved by minimizing the deviations from the target. The product or

process should be so designed that it is immune to uncontrollable environmental

variables.

The cost of quality should be measured as a function of deviation from the standard and

the losses should be measured system-wide.

Taguchi proposes “off-line” strategy for quality improvement as an alternative to an

attempt to inspect quality into a product on the production line. He observes that poor

quality cannot be improved by the process of inspection, screening and salvaging. No

amount of inspection can put quality back into the product.

6.2 TAGUCHI METHOD’S CATEGORIES

6.2.1 Static Problems

Generally, a process to be optimized has several control factors which directly decide the

target or desired value of the output. The optimization then involves determining the best control

factor levels so that the output is at the target value. Such a problem is called as a "STATIC

PROBLEM". Noise is shown to be present in the process but should have no effect on the

output! This is the primary aim of the Taguchi experiments - to minimize variations in output

even though noise is present in the process. The process is then said to have become ROBUST.

6.2.1.1 Signal to Noise Ratio

Once the experimental design has been determined and the trials have been carried out,

the measured performance characteristic from each trial can be used to analyse the relative effect

of the different parameters. The product/process/system design phase involves deciding the best

values/levels for the control factors. The signal to noise (S/N) ratio is an ideal metric for that

purpose.

The S/N ratio, as stated earlier, is a concurrent statistic. A concurrent statistic is able to

look at two characteristics of a distribution and roll these characteristics into a single number or

40

figure of merit. The S/N ratio combines both the parameters (the mean level of the quality

characteristic and variance around this mean) into a single metric. A high value of S/N implies

that signal is much higher than the random effects of noise factors. Process operation consistent

with highest S/N always yields optimum quality with minimum variation.

The S/N ratio consolidates several repetitions into one value. The equation for calculating

S/N ratios for “smaller is better” (LB), “larger is better” (HB) and “nominal is best” (NB) types

of characteristics.

6.3 PARAMETERS CONSIDERATION FOR EXPERIMENT:

Input parameters

Hole Size

Lateral Distance

Linear Distance

Output parameters

Stress

Deformation

Table 6.1: Range of Process Parameters

Input parameters Level

1 2 3

Hole Size 40 42 44

Lateral Distance 250 270 290

Linear Distance 250 270 290

In the present study hole size, lateral & linear distance selected as input parameter. The

range of selected process parameters are shown in Table no. 4.1.

While we take other data for this parameter stress can increase on platen. We also

perform on hole size 38, 45, both distance 249, 291 but stress can increased. So, we

cannot take consideration this level of parameter.[13]

41

6.4 SELECTION OF ORTHOGONAL ARRAY (OA)

In selecting an appropriate OA, the pre-requisites are:

Selection of process parameters and/or interactions to be evaluated.

Selection of number of levels for the selected parameters

The determination of which parameters to investigate hinges upon the product or process

performance characteristics or responses of interest. Several methods are suggested by Taguchi

for determining which parameters to include in an experiment. These are:

Brainstorming

Flow charting

Cause-Effect diagrams

The total Degrees of Freedom (DOF) of an experiment is a direct function of total

number of trials. If the number of levels of a parameter increases, the DOF of the parameter also

increases because the DOF of a parameter is the number of levels minus one. Thus, increasing

the number of levels for a parameter increases the total degrees of freedom in the experiment

which in turn increases the total number of trials. Knowing the number of parameters and the

number of levels, the proper orthogonal array can be selected. Using the array selector table

shown below, the name of the appropriate array can be found by looking at the column and row

corresponding to the number of parameters and number of levels. Once the name has been

determined. The orthogonal array selector is shown in Figure 4.4. The number as subscript in the

array designation indicates the number of trials in that array. The total degrees of freedom (DOF)

available in an OA are equal to the number of trials minus one.

Fig.6.1The Orthogonal Array Selector

42

fLn=N-1

Where,

fLn= Total degrees of freedom of an Orthogonal Array

LN = OA designation

N = Number of trials

When a particular OA is selected for an experiment, the following inequality must be

satisfied: fLn ≥ Total degree of freedom required for Parameters and Interactions depending on

the number of levels of the parameters and total DOF required for the Experiment, a suitable OA

is selected.

Table 6.2: The Scheme of L9 Design of Experimental

Experiment No. Hole Size Lateral Distance Linear Distance

1 40 250 250

2 40 270 270

3 40 290 290

4 42 250 270

5 42 270 290

6 42 290 250

7 44 250 290

8 44 270 250

9 44 290 270

For these parameters L9 orthogonal will be generated as above and 9 run can be

considered.

After generating these runs the output variation and result of analysis will generated in

ansys workbench.

43

6.5 VARIATION IN PARAMETER FOR TAGUCHI’S DESIGN

Case 1

Hole Size: 40 Lateral Distance: 250 Linear Distance: 250

Fig. 6.2 Case-1 modeling

Total Deformation: 0.2094 mm

Fig. 6.3 Case-1 Total Deformation

Equivalent stress: 185.36 MPa

Fig. 6.4 Case-1 Equivalent stress

44

Case 2







45

Case 3







46

Case 4







47

Case 5







48

Case 6







49

Case 7







50

Case 8







51

Case 9







52

6.6 DATA ANALYSIS

A number of methods have been suggested by Taguchi for analyzing the data:

observation method, ranking method, column effect method, ANOVA, S/N ANOVA, plot of

average response curves, interaction graphs etc. However, in the present investigation the

following methods have been used:

ANOVA for S/N data

S/N response graphs

Interaction graphs

Residual graphs

The plot of average responses at each level of a parameter indicates the trend. It is a

pictorial representation of the effect of parameter on the response. The change in the response

characteristic with the change in levels of a parameter can easily be visualized from these curves.

Typically, ANOVA for OA„s are conducted in the same manner as other structured experiments

The S/N ratio is treated as a response of the experiment, which is a measure of the variation

within a trial when noise factors are present. A standard ANOVA can be conducted on S/N ratio

which will identify the significant parameters (mean and variation). Interaction graphs are used

to select the best combination of interactive parameters. Residual plots are used to check the

accuracy.

53

CHAPTER -7

ANALYSIS AND DISCUSSION OF RESULTS

7.1 TESTING RESULTS

After generating runs of all 9 case the output variation and result of analysis will

generated in ANSYS workbench and results are recorded in a table as shown below.

Table 7.1 Experimental results

Experiment

No.

Hole Size

(mm)

Lateral Distance

(mm)

Linear Distance

(mm)

Stress

(MPa)

Deformation

(mm)

1 40 250 250 185.36 0.2094

2 40 270 270 183.72 0.2096

3 40 290 290 184.57 0.2098

4 42 250 270 186.01 0.2097

5 42 270 290 185.25 0.2094

6 42 290 250 185.72 0.2097

7 44 250 290 187.06 0.2101

8 44 270 250 184.13 0.2094

9 44 290 270 185.15 0.2108

7.2 Analysis Software MINITAB16

Minitab is a statistics package used for analysis of experimental data. It was developed at

the Pennsylvania state university by researchers Barbara F. Ryan, Jr., and Brian L. Joiner

in 1972. The goal of robust experimentation is to find an optimal combination of control

factor Settings that achieve robustness against noise factors. MINITAB generates main

effects and interaction plots for signal-to-noise ratio (S/N ratios) vs. control factors.

54

MINITAB is a powerful, easy-to-use, statistical software package that provides a wide

range of basic and advanced data analysis capabilities. MINITAB's straightforward

command structure makes it accessible to users with a great variety of background and

experience. MINITAB runs on PC and Macintosh computers, and most of the leading

workstations, minicomputers and mainframe computers. While MINITAB differs across

releases and computer platforms, the core of MINITAB - the worksheet and commands.

Fig.7.1 shows that screen view of MINITAB16 software described whole data which are

used in present study.

Fig 7.1 Screen view of MINITAB16 software

7.3 S/N Ratio Calculation for Stress and Deformation

In this the observe value of Stress and Deformation are transform in S/N ratio values to find out

the optimum combination of parameters for response variable. In stress and deformation

response ―smaller is better‖ is objective characteristics.

55

7.3.1 Main Effects Plot of Stress

The main effects plot for S/N ratio of Stress versus Hole, Lateral Distance, Linear

Distance are shown in fig.7.3.

444240

186.0

185.5

185.0

184.5

290270250

290270250

186.0

185.5

185.0

184.5

HOLE

Mean o

f M

eans

LATERAL DISTANCE

LINEAR DISTANCE

Main Effects Plot for MeansData Means

444240

-45.32

-45.34

-45.36

-45.38

-45.40

290270250

290270250

-45.32

-45.34

-45.36

-45.38

-45.40

HOLE

Mean o

f SN r

ati

os

LATERAL DISTANCE

LINEAR DISTANCE

Main Effects Plot for SN ratiosData Means

Signal-to-noise: Smaller is better

Fig.7.2 Effect of input parameter on Stress

Fig.7.3 shows that better stress will meet at hole size 40 mm, lateral distance 270 mm and

linear distance 270 mm. The graph generate by use of minitab-16 statistical software for

stress.

56

It has been conclude that the optimum combination of each process parameter for

stress will meet at hole size [A2], lateral distance [B2], linear distance [C2].

7.3.2 Main Effects Plot of Deformation

The main effects plot for S/N ratio of Deformation versus Hole, Lateral Distance,

Linear Distance are shown in fig.7.4.

444240

0.21000

0.20985

0.20970

0.20955

0.20940

290270250

290270250

0.21000

0.20985

0.20970

0.20955

0.20940

HOLE

Mean o

f M

eans

LATERAL DISTANCE

LINEAR DISTANCE

Main Effects Plot for MeansData Means

444240

13.58

13.57

13.56

13.55290270250

290270250

13.58

13.57

13.56

13.55

HOLE

Mean o

f SN r

ati

os

LATERAL DISTANCE

LINEAR DISTANCE

Main Effects Plot for SN ratiosData Means

Signal-to-noise: Smaller is better

Fig.7.3 Effect of input parameter on Deformation

57

Fig.7.4 shows that better Deformation will meet at hole size 40 mm, lateral distance 270

mm and linear distance 270 mm. The graph generate by use of minitab-16 statistical

software for Deformation.

It has been conclude that the optimum combination of each process parameter for

deformation will meet at hole size [A2], lateral distance [B2], linear distance [C2].

7.4 ANALYSIS OF VARIANCE (ANOVA)

In design of experiment the results are analyzed due to one or more of the following three

objectives. [14]

1. To establish the best or the optimum condition for a product or a process.

2. To estimate the contribution of individual factors.

3. To estimate the response under the optimum condition.

The main output from an analysis of variance study is arranged in a table. List the sources of

variation, their degrees of freedom, the total sum of squares, and the mean squares. The

analysis of variance table also includes the F-statistics and p-values. Use these to determine

whether the predictors or factors are significantly related to the response. ANOVA tables are

also used in regression and DOE analysis.

Analysis of variance (ANOVA) Terms & Notations:

n = Number of trials C.F. = Correction factor

E = Error P = Percentage contribution

F = Variance ratio T = Total of results

𝑓 = Degree of freedom S = sum of squares

𝑓E = Degree of freedom of error V = Mean squares (variance)

𝑓T = total degree of freedom

Total numbers of trail:

The total number of trial is the sum of numbers of trials at each level.

58

Degree of freedom:

It is a measure of amount of information that can be uniquely determined from a given set of

data. DOF for data concerning a factor equals one less than the number of levels.

Variance:

Variance measures the distribution of the data about the mean of the data.

Variance ratio:

Variance ratio is the ratio of variance due to the effect of a factor and variance due to the error

term. This ratio is used to measure the significance of the factor under investigation with respect

to the variance of all the factors included in the error term. The F value obtained in the analysis is

compared with a value from standard F – tables for a given level of significance.

When the computed value is less than the value determined from the F tables at the selected level

of significance, the factor does not contribute to the sum of squares within the confidence level.

7.4.1 Analysis of Variance for stress

Table 7.2 Analysis of Variance for stress

Source DF Seq SS Adj SS Adj MS F P

HOLE 2 2.0816 2.0816 1.0408 3.86 0.006

LATERAL

DISTANCE

2 4.7583 4.7583 2.3791 8.82 0.002

LINEAR

DISTANCE

2 0.7664 0.7664 0.3832 1.42 0.000

Error 2 0.5394 0.5394 0.2697

Total 8 8.1457

S = 0.399305 R-Sq = 93.38% R-Sq(adj) = 73.51%

From ANOVA result it is observed that the hole size, lateral distance, linear distance are

influencing parameter for stress. The confidence level (CL) used for investigation is taken

93% for this investigation. The parameter R-Sq described the amount of variation is

59

explained by the input factor. R-Sq= 93.38% which indicate that the model is able to

predicate the response with high accuracy

7.4.2 Analysis of Variance for deformation

Table 7.3 Analysis of Variance for deformation

Source DF Seq SS Adj SS Adj MS F P

HOLE 2 0.0000005 0.0000005 0.0000003 5.77 0.148

LATERAL

DISTANCE

2

0.0000006 0.0000006 0.0000003 7.00 0.125

LINEAR

DISTANCE

2

0.0000004 0.0000004 0.0000002 4.92 0.169

Error 2 0.0000001 0.0000001

0.0000000

Total 8 0.0000016

S = 0.000208167 R-Sq = 94.65% R-Sq(adj) = 78.60%

From ANOVA result it is observed that the hole size, lateral distance, linear distance are

influencing parameter for deformation. The confidence level (CL) used for investigation is

taken 94 % for this investigation. The parameter R-Sq described the amount of variation is

explained by the input factor. R-Sq= 94.65% which indicate that the model is able to

predicate the response with high accuracy

The One-Way ANOVA is used when you have one categorical and one quantitative variable

and you want to compare the means of the quantitative variable across different categories.

With the use of this method main effects plot and interaction plot graph have been generated

shown in fig.

60

444240

186.0

185.5

185.0

184.5

290270250

290270250

186.0

185.5

185.0

184.5

HOLE

Mean

LATERAL DISTANCE

LINEAR DISTANCE

Main Effects Plot for STRESSData Means

444240

0.21000

0.20985

0.20970

0.20955

0.20940

290270250

290270250

0.21000

0.20985

0.20970

0.20955

0.20940

HOLE

Mean

LATERAL DISTANCE

LINEAR DISTANCE

Main Effects Plot for DEFORMATIONData Means

Fig 7.4 Main effects plot for stress and deformation

61

290270250 290270250

187.5

186.0

184.5

187.5

186.0

184.5

HOLE

LA TERA L DISTA NCE

LINEA R DISTA NCE

40

42

44

HOLE

250

270

290

DISTANCE

LATERAL

Interaction Plot for STRESSData Means

290270250 290270250

0.2105

0.2100

0.2095

0.2105

0.2100

0.2095

HOLE

LA TERA L DISTA NCE

LINEA R DISTA NCE

40

42

44

HOLE

250

270

290

DISTANCE

LATERAL

Interaction Plot for DEFORMATIONData Means

Fig 7.5 Interaction plot for stress and deformation

62

One-Way ANOVA: Hole, Lateral Distance, Linear Distance, Stress, Deflection

Table 7.4 Analysis of Variance for stress and deformation

Source DF SS MS F P

Factor 4 576727 144182 1193.52 0.000

Error 40 4832 121

Total 44 581559

S = 10.99 R-Sq = 99.17% R-Sq(adj) = 99.09%

Table 7.5 Analysis of Variance for stress and deformation

Level N Mean StDev

Hole 9 42.00 1.73

Lateral Distance 9 270.00 17.32

Linear Distance 9 270.00 17.32

Stress 9 185.22 1.01

Deflection 9 0.21 0.00

Pooled StDev = 10.99

In this method result it is observed that the parameter R-Sq described the amount of

variation. R-Sq= 78.60% which indicate that the model is able to predicate the response with

high accuracy. With use of this method optimized result has been predict.

63

CHAPTER 8

RESULT AND DISCUSSION

In this chapter the combined approach of Taguchi and ANSYS is discussed. After this nine

analysis is carried out of platen for Taguchi selected array. This result is used in Taguchi

analysis and from that analysis it can be concluded that case 2 which has hole size 40mm,

lateral distance 270mm, linear distance 270mm gives the nominal Stress, Deformation of

platen is and this combination can be utilized to optimize platen.

Optimized Results based on factor level for prediction on ANOVA

Hole

size(mm)

Lateral distance

(mm)

Linear distance

(mm)

Stress (Mpa) Deformation

(mm)

40 270 270 183.72 0.2096

In design of experiment perform on different level design with use of minitab software 9

experiment introduce. This factor level prediction analyzed by ANSYS and gets the value of

stress and deformation.

When performing factor level for prediction parameter Stress, Deformation of platen is

nominal for hole size 40mm, lateral distance 270mm, linear distance 270mm.

With use of this combination material remove from platen, weight and cost optimized.

64

CHAPTER 9

CONSLUSION AND FUTURE SCOPE

In this research, three parameters: hole size, lateral distance, linear distance were analyzed

for material removal from platen. Taguchi method was used in this research to conduct an

experimentation plan to determine the optimum parameters settings that affect the output

characteristic responses as proposed in this study such as stress and deformation

Optimization of all responses has been carried out with help of ANOVA method and the best

factor setting obtained is hole size 40mm, lateral distance 270mm, linear distance 270mm.

This parameter gives optimum value of material removal from platen. Hence, with use of this

parameter we get 5% cost can optimized.

Future scope:

In present work, optimization of two responses, stress and deformation considered for

platen. Due to time constraints, we optimized only platen of injection molding machine

although clamping assembly optimization may be carried out in future. Moreover in this

work kinematic analysis of clamping system of injection molding machine, linear elastic

fracture mechanics analysis of platen also carried out in future.

65

REFERENCES:

RESEARCH PAPERS

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11. Xiaowei Li, Zhiming Jin, Yajun Zhang “Kinematic calculation analysis of micro

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67

DISSERTATIONS

19. Nirav B. Barevadiya “Optimization of Wax Tank Parameter In Injection Molding

Machine to Maintain Uniform Temperature of Wax” U. V. Patel College of Engiineeriing

Ganpat Uniiversiity Kherva, Mehsana, May-2012.

20. Rikard Johansson and Daniel Konijnendijk “Injection Moulding Simulation -A fnite

element approach to analyse the thermodynamics in an IM tool”, Lund University, Lund,

Sweden, March 2007

21. Andreas Östergren, Master‟s Thesis in the Applied Mechanics Department of Applied

Mechanics Division of Material and Computational Mechanics “Prediction of residual

stresses in injection moulded parts” Chalmers University Of Technology, Göteborg,

Sweden 2013, ISSN 1652-8557

BOOKS

22. Prof. sham Tickoo, Deepak maini “Solidworks 2007 for engineer and designers”,

Dreamtech press, First Edition 2007

23. Genichi Taguchi, “System of experimental design: engineering methods to optimize

quality and minimize costs”, Volume 1(1987).

WEB REFERENCES:

24. www.plasticsdom.com

25. http://www.dc.endr.scu.edu/cmdoc/dg_doc/develop/process/control/b1000002.htm

26. www.elitemachinerysystem.com

27. www.cheresources.com

28. www.sinotech.com

https://www.google.co.in/search?tbo=p&tbm=bks&q=inauthor:%22Genichi+Taguchi%22

http://www.dc.endr.scu.edu/cmdoc/dg_doc/develop/process/control/b1000002.htm

http://www.elitemachinerysystem.com/

http://www.cheresources.com/

http://www.sinotech.com/

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