PRESENTED

BY:

MR. AHMAD

AIZUDDIN ABD AZIZ

PhD STUDENT.

TITLE:

INVESTIGATING

OF PLASTIC

INJECTING

MOLDING

PROCESS

OPTIMIZATION IN

COMPLEX SHAPE

PRODUCT

�Introduction

�Methodologies

�Result and discussions

�Conclusion

Overview

INTRODUCTION

INJECTION MOLDING

• Manufacturing process for making complex shapes from polymeric materials. The process involves heating up the polymer, injecting the molten polymer into a mold, cooling the polymer in the mold, and ejecting the part.

• Injection molding is a complex technology with possible production problems. They can be caused either by defects in the molds or more often by part processing which is molding.

CONT…The common defect are:

Warping Short shot Sink marks

Flash Weld lines

Phone Cover model

Product

• Nowadays, in mobile phone manufacturing or industries

are made a lot of accessories as a protector from

damage or made a very nice appearance. The phone

cover also one of the accessories is made to protector

the mobile phone from damage. The whole part for

phone cover (upper and bottom casing, transference

keypad and screen) is not injected in the same mold

simultaneously, they are come batch by batch instead of

their type, which means, for example, the upper and

bottom casing come from one mold and the other pieces

also comes from one mold.

cont

cont

• The main problem is to inject the whole of part

for phone cover (upper and bottom casing,

transference keypad and screen) which come in

diversity of shape, size, and volume in one mold

need the most optimize injection parameter

setting because if one piece is rejected, the set

is not completed, in order to replace the rejected

piece, it needs another injection which will lead

to more cost and higher inventory.

OBJECTIVES

The main objectives of the project are:

• To simulate the product using CAD software.

• To find the optimum moulding parameter of

plastic injection moulding process.

• To analyses the material flows of two and three-

plate molds in injection molding process.

Prepare CAD

Saved in x_t file type for MPI simulation

Meshing A continuous surface or volume is broken into many connected but

discrete elements, forming a mesh.

The time required to mesh the part will depend on the size and

complexity of the part.

Runner layouts

H-type (branched) Radial-star

Type of Gate Chosen

AC Technology, 1996. C-MOLD Design Guide. New York, USA.

Type of Gate Chosen

AC Technology, 1996. C-MOLD Design Guide. New York, USA.

RESULT

AND

DISCUSSION

In order to find the most optimize layout arrangement of

phone cover mold, the result from 2 layouts should be

compared. The selected results of each layout that will cover

are:

1. Fill time

2. Average velocity

3. Clamp force

4. Pressure

5. Time to reach ejection temperature (Cooling time)

6. Volumetric shrinkage.

1. Fill time

The Fill time result shows the position of the flow front at regular intervals

as the cavity fills. At the start of injection, the result is dark blue, and the

last places to fill are red. The shortest time is H-type layout with 3.148s but

two part in H-type layout will get flashing defect. Even fill time in radial-

star layout takes 3.176s, this layout is the most balanced with all the part

filled almost uniformly.

Standard H-Types Radial-Star

3.148s 3.176s

2. Average velocityStandard H-Types Radial-Star

953.4cm/s 754.3cm/s

The Average velocity, part show the result of the velocity profile across

the part thickness, calculated at the end of cooling time. From the result,

can see that the H-type layout reach over 953.4 cm/s rather than over

754.3cm/s in radial-star layout

3. Clamp forceStandard H-Types Radial-Star

38 tonne 28 tonne

Clamp force is the force required to hold the mold closed while an opposing

pressure is exerted by the plastic injected into the cavity. Clearly can see that

radial star layout just need 28 tonne clamp force, while the stabdard H-type just

need 38 tonne clamp force . This means the parts of radial star layout should be

no defect of flashing.

4. Pressure Standard H-Types Radial-Star

< 9.875 MPa < 9.053 MPa

The Pressure result is generated from a Fill analysis, and shows the

pressure distribution through the flow path inside the mold at the time

the result was written. The radial star layout got the lowest pressure

which is 9.053 MPa compared to h-type layout which over 9.875 MPa.

This is because radial star layout have bigger runner size and volume.

5. Time to reach ejection

temperature (Cooling Time)Standard H-Types Radial-Star

50.05s 30.19s

6. Volumetric shrinkage

Standard H-Types Radial-Star

The Volumetric shrinkage result shows the volumetric shrinkage for

each area as a percent of the original volume.

Comparison Criteria H-type Radial-star

Fill time X

Average velocity X

Clamp force X

Pressure X

Time to reach ejection

temperature

X

Volumetric shrinkage X

Radial-star was chosen as the most optimize runner layout

Advantages & Disadvantages

Two & Three Plate Molds

Conclusion

• Results show that three plate moulding satisfy

both process quality and the product quality

characteristics in this injection moulding

process.

• The radial star layout was the better layout for

parts injection molding process.

• Although this optimization study only

emphasis in the runner layout and product

configuration in the mold, the proposed

approach is feasible and effective to assist the

today manufacturing industry needed for

complex shape.

REFERENCES

[1] Stanek, M., Manas, D., Manas, M., Javorik, J. Simulation of

injection molding process by cad mould rubber. Int. J. Math.

Comput. Simul., 5.5, 413-421 (2011).

[2] Chen, W. C., & Lin, S. B, Int. J. App. Phys. Math., Vol. 3, No. 6,

373-375 (2013).

[3] Dang, X.P. Simulation Modelling Practice and Theory 41, 15-27

(2014).

[4] P.K. Bharti et al. Int. J. Eng. Sci. Tech., Vol. 2(9), 4540-4554

(2010).

[5] Shen, C., Wang, L., & Li, Q. J. Mater. Proc. Tech., 183.2, 412-

418 (2007).

[6] Tang, S. H., et al. J. Mater. Proc. Tech., 171.2, 259-267 (2006).