ISSN: 2454-1362, Design and … · Economics in injection moulding) Spain, (2013); M.C. Song, Z....

Imperial Journal of Interdisciplinary Research (IJIR) Vol-2, Issue-6, 2016 ISSN: 2454-1362, http://www.onlinejournal.in

Imperial Journal of Interdisciplinary Research (IJIR) Page 867

Design and Analysis of Injection Moulding Die

and Optimization of Runner Cross-Section Using

Analytical Hierarchy Process (AHP)

Manish S. Patil1 , Pranjal Singh

2, Shubh Bajaj

3, Vinay Sharma

4, Vipul

Kumar Panchal5

1Assistant Professor IMSEC, Uttar Pradesh, India

2,3,4,5Student, Bachelor of Engineering Student, IMSEC, Uttar Pradesh, India

Abstract. : Injection molding process is one of the

most process to producing single functional parts or

say non-continues parts components in large numbers

in a short span of time.

The designing of mould is a complicated process. In

mould designing various parameters are to be

adjusted for successful mould design. Here we use the

CAD software to design the mould and to analysis of

various parameters for design of mould. The CAD

software’s use are CREO 2.0 or SOLIDWORKS and

ANSYS. Here we design the moulds by using both

analytical and software methods for various

parameters. The main failure modes of the plastic

mould are surface wear, deformation and fracture.

The main failure reasons depend on working

conditions, mould materials and thermal properties,

stresses due to ingates etc. Material selection of

plastic mould is decided by their using performances

and life of material. By analytic calculations

selections of gate types, gate size, sprue, runners,

margin for clamping holes and all other parameters

and locations in mould plate. The analysis of mould

we can suggest a proper material selection, size, and

optimizing the shape of the ingate or runner and the

position of the runner.

To avoid the failure of shape of the runner and the

position of the runner is to be selected properly so that

the stress is reduces and the failure of the die is

avoided and the stress can be minimized.

Here we use the analytical hierarchy process for the

optimization of the runner cross section. We take the

ANSYS results and apply this technique on it so that

we get the optimum cross section for the runner and

we take that runner cross section and design the

moulding die, after designing the moulding,

manufacture the die on CNC machine.

I. Introduction.

Injection moulding technology is used for a

variety of different products in almost all branches of

industry. This process now integrated with computer

control make the production better in. quality and

better quantity. In designing the mould for injection

moulding, the accuracy in making mould very

important in order to reduce cost. Before this, the

mould designer used manual analysis to the mould.

But now, there is software that can simulate the

analysis of the mould that wants to develop. Clearly,

more and more manufacturers are using computational

and analytical techniques to reduced design time and

cost while significantly improving yield and quality.

Simulation software allows to do some trouble

shooting very easily.

The die is the most complex part for the

design. Lot of calculation and thumb rules are

available for the design of the die. For complex shape,

complicated die is available and for complicated die,

so many stresses act on the surface of the die, that

stresses are sometimes leads to the failure of the die.

The high stress area of the die is runner area, because

through the runner high pressure liquid is passes and at

the junction of the runner and die area shape is

complicated so that this area is one where lot of

stresses are coming, and our aim is to avoid or reduce

that stress value so that the failure of the die is

avoided.

The various literatures which helped in

carrying forward the work are Bohai He, (Research on

the failure and material selection of Plastic mould),

China, 2011; L.W. Seow, Y.C. (Optimizing flow in

plastic injection moulding), Australia, 1996; B.

Nardin, K. Kuzman, Z. Kampus, (Injection moulding

simulation results as an input to the injection moulding

http://www.onlinejournal.in/




process), Slovenia; D.E. Dimla, M. Camilotto, F.

Miani, (Design and optimisation of conformal cooling

channels in injection moulding tools), Italy; S.H.

Tang, Y.M. Kong, S.M. Sapuan, R. Samin, S.

Sulaiman (Design and thermal analysis of plastic

injection mould), Malaysia, (2005); M.A. Sellesa, S.

Sanchez-Caballeroa, E. Perez-Bernabeu, (Analysis and

review of different tools to calculate the production

Economics in injection moulding) Spain, (2013); M.C.

Song, Z. Liu, M.J. Wang, T.M. Yu, D.Y. Zhao,

(Research on effects of injection process parameters

on the Moulding process for ultra-thin wall plastic

parts), China, (2006).

II. Die Design and Analysis.

(A). Die Design.

Calculation for Die.

Die design for the product is our main area of

concern. So, for the correct die design we need all the

dimensions of the die which could be calculated using

the following formula.

Thickness of die T =

Where F=maximum force applied on die (N),

L=length of cavity (mm),

B=width of cavity (mm),

f =tensile stress of material of die (N/mm²).

Now, margin along the width of die= (.5*thickness of

die)

Now for calculating the length of diagonals:

Diagonals = (2*length of product’s

cavity+2*margin+2*distance of cavity from center)

Since we know the diagonal of the face of die we can

find out the side of its face.

Side of face of die=

Calculation of Runner.

For the calculation of runner, we have to

calculate the area of cross-section and the length of the

runner.

For calculating the area of cross-section of

circular runner we need the diameter of the runner.

Diameter of runner D =

Where D= diameter of runner (mm)

w= weight of material to be injected (gm)

l= length of runner (mm).





Variables used for Runner Design.

The variables which we used for the design

of the runner is the shape of cross-section of the

runner. The various shapes we used as variables are.

Circular

Hexagonal

Square

Rectangular

Variables used for Die Design.

The variables which we used for the design

of the die is the position of the runner. We used runner

at three different positions which are as follows.

Upper position

of runner

Centre position of

runner

Lower

position of

runner

(B). Analysis on Die.

(i). Upper Die.

(ii). Lower Die.

Circular Cross-section.





HEXAGONAL CROSS-SECTION.





SQUARE CROSS-SECTION.




Imperial Journal of Interdisciplinary Research (IJIR) 74

RECTANGULAR CROSS-SECTION.





Results of AHP Method.

For the calculation of the final results through

the AHP process, we have to give the preferences to

the different variables we used during our analysis.

This is called as Ranking Scale. Now we have to find

out the geometric mean (G.M.) for those ranking and

then we calculate sum of G.M. of all rows and then we

find out the ratio of G.M. to sum of G.M. The

calculated result is called weightage. And this

weightage we calculated gives the result for different

parameters. After applying the whole AHP process

and calculating parameters for different variables we

have concluded that from different four cross-sections

and positions of runner, we have to select the

maximum to maximize the value and to minimize

select minimum.

The table in which the calculated result with

the help of weightage is as follows.

Conclusion from AHP Method.

Result shows that if we want to maximize the

value, we select the maximum value and if we want to

minimize the value, we select minimum value.

For circular cross-section all the Criteria will

be minimum. So we can select the ‘Circular Cross-

section’ as best selection or optimum selection.

III. Final Result and Discussion.

Geometric mean is maximum in case of

circular cross-section shaped area with runner in

centre position die.





The result which we are getting i.e. the

circular cross-section die has the least stresses

induced, it is because of the reason that in the circular

cross-section runner we get stream line flow of the

plastic material into the cavity due to which the

stresses induced in the die are very less. Also from the

three positions of the runner i.e. centre, upper and

lower the stresses produced are less in centre position

because the material has to flow a less distance in

runner and hence less pressure is exerted. Pressure was

more in upper and lower position of the die. The graph

for the final result is shown as follow.

IV. Conclusion.

The concept of AHP use for the selection of

multiple criteria selection process. For selection of

mould design parameter, we choose the AHP method

for selection process. We use new approach for the

selection design parameter. This method gives very

accurate and value based result.

So using this concept for selecting of runner

cross section shape. We get optimum result and also

we use for manufacturing of mould. The AHP concept

easy to calculate and not required any lengthy

calculations. So AHP method is very useful when time

is matter for the selection of any process.

Here we use SOLIDWORKS 2014 for the

designing of dies and runners of different cross-

sections (like circular, rectangular, square and

hexagonal). The analysis work of dies and runners is

done by using ANSYS 14.5 simulator. We work with

integrating theoretical aspect with practical study and

get the desired output.

From Stress analysis result, we conclude that

MOULD DESIGN with CIRCULAR cross section has

given optimum result of all stress analysis parameters

like cooling time, strength, mouldability, etc.

V. Acknowledgement.

This research paper is made possible through

help and support of our project guide. His kind

guidance during the entire period of our research work

was very helpful. His consistence support and advice

has helped us to complete this research paper

successfully. His sincerity, thoroughness and has

been a constant source of inspiration for us. It is only

his cognizant efforts that our endeavors have seen

light of the day.

The contribution of all faculty members of

the department for their kind assistance and

cooperation during the development of our project and

research paper is acknowledged by us. Last but not the

least we would like to thank our friends and family for

their motivation.

VI. References.

[1]. Bohai He, Research on the failure and material

selection of Plastic mould. China, 2011.

[2]. B. Nardin, K. Kuzman, Z. Kampus Research on

Injection moulding simulation results as an input to

the injection moulding process, Slovenia, 2002.

[3]. D.E. Dimla, M. Camilotto, F. Miani Research on

Design and optimization of conformal cooling

channels in injection moulding tools.

[4]. L.W. Seow, Y.C. Optimizing flow in plastic injection

moulding. Lam Journal of Materials Processing

Technology, Australia, 1996.

[5]. M.A. Sellesa, S. Sanchez-Caballeroa, E. Perez-

Bernabeu, Analysis and review of different tools to

calculate the production Economics in injection

moulding. Procedia technology, Spain 2013.

[6]. P. H. Joshi., Press tools design and construction, S.

Chand & Company Ltd. New Delhi, India. 2000.

[7]. Reddy KB, Ayachit NH, Venkatesha MK, A

Theoretical method for performance evaluation of

technical institutions - Analytic Hierarchy Process

approach, The Indian journal of technical education,

Vol.27, 2004.

[8]. S.H. Tang, Y.M. Kong, S.M. Sapuan, R. Samin, S.

Sulaiman MalaysiaDesign and thermal analysis of

plastic injection mould Journal of Materials

Processing Technology, 2006.

[9]. T.L. Saaty, the Analytic Hierarchy Process, McGraw

Hill, NY, 1988.

[10]. V.S. Lai, R.P. Trueblood, B.K. Wong, Software

selection: a case study of the application of the





analytical hierarchical process to the selection of a

multimedia authoring system, Inform. Manage, 1999.



ISSN: 2454-1362, Design and … · Economics in injection moulding) Spain, (2013); M.C. Song, Z....

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