JBR moldflow analysis example

 Case Study    |      2017-06-24

To analysis original design, cooling and check flow , warp





Plastic Material Introduction

ABS  Cycolac GPM5500 : SABIC Innovative Plastics B.V.

The customer not supply the grade of material, so we choose a general material.

1. Melt Density                              0.93839       g/cu.cm

2. Solid Density                             1.0541       g /cu.cm

3. Ejection Temperature              85 deg.C

4. Recommended Mold Temperature 60   deg.C

5. Recommended Melt Temperature   250  deg.C

6. Absolute Max. Melt Temperature   290 deg.C

 7. Melt  Temperature Minimum   230.0 deg.C

 8. Melt  Temperature Maximum  270.0 deg.C

 9. Mold  Temperature Minimum   40.0 deg.C

10. Mold  Temperature Maximum  80.0 deg.C

11. Maximum Shear Rate           50000.00 1/s

12. Maximum Shear Stress           0.300 MPa





Part Introduction







Cooling System Design




The cooling system is   shown   by   picture, the diameter of channel is 8.0mm.




Case 1

Feed System Design



1x2 cavities, three plates mold, Cold   runner +Pin gate, the  size is   shown   by     picture.




Processing conditions


Filling Conditions :

Mold temperature :  60.00 deg.C

Melt temperature :     250.00 deg.C              

Injection time 1.3sec


Cooling Conditions:

Coolant Temperature(Cavity)    50 deg.C

Coolant Temperature(Core)       50 deg.C


Fill time


Shown by picture the flow status is imbalance, cause short shot, because the gate close to the thin place.


Case 2



1x2 cavities, three plates mold, Cold   runner +Pin gate, the  size is   shown   by     picture.



Processing conditions


Filling Conditions :

Mold temperature :  60.00 deg.C

Melt temperature :     250.00 deg.C              

Injection time 1.7sec


Cooling Conditions:

Coolant Temperature(Cavity)    50 deg.C

Coolant Temperature(Core)       50 deg.C


Fill time



Shown by picture the flow status is imbalance, cause short shot, because the gate close to the thin place.





Case 3



1x2 cavities, three plates mold, Cold   runner +Pin gate, the  size is   shown   by     picture.


Processing conditions

Filling Conditions :

Mold temperature :  60.00 deg.C

Melt temperature :     250.00 deg.C              

Injection time 1.3sec

Cooling Conditions:

Coolant Temperature(Cavity)    50 deg.C

Coolant Temperature(Core)       50 deg.C




Circuit coolant Temperature



Temperature (top) part



Top temperature of  part is balance shown by   picture.



Bottom temperature of   part is  balance shown by picture.  


Fill time



Pressure at V/P switchover

The pressure at V/P switchover is 98.7 MPa .


Temperature at flow front


Temperature at flow front is imbalance shown by picture.


Air traps



The magenta circles are possible air traps shown by picture, please attention venting.



Weld lines



The color lines are possible weld lines.



Volumetric shrinkage



Volumetric shrinkage is imbalance show by picture, please  attention    the  setting of packing.


Sink marks estimate

The Sink marks estimate is imbalance show by picture, please  attention    the  setting of packing.


Frozen layer Fraction



Injection Pressure & Clamp Force





Deflection – All direction


Deflection of All direction is imbalance, possible cause warp.


Deflection – X direction





Deflection – Y direction





Deflection – Z direction




The results:

The flow status is balance, the injection and packing pressure is normal.  

The volumetric shrinkage is imbalance, please attention the  setting of packing.

Deflection of X&Y direction is balance, cause warp is little. Deflection of Z direction is imbalance, possible   cause warp.







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