Fill+Pack+Warp Analysis on a Storage box which is made by Plastic Injection Molding

Aim :

• To obtain the results of a Fill+Pack+Warp Analysis that is run on a model.
• To identify the main contributing factor for the warpage on the model from results.

Procedure :

1. I have imported a model (STEP file) of Plastic storage-box used in industries for storing miscellenous small light weight parts like Nuts,bolts,pneumatic joints and fittings,etc.
2. This model was then meshed in Autocad Moldflow Synergy with Dual Domain Mesh having edge length of 1.6mm.
3. It was then diagnosed for meshing defects such as Free edges,Non Manifold edges,Orientation defects,Collapsed elements,etc.
4. After replacing the defective elements with new elements, the model was then progressed for further analysis.
5. Material selected was Generic Polypropylene, which is commonly used for the this part. Material properties are as follows :
6. Gate location analyis was then done on the model, result is as below:
7. Gate location was selected same as shown but from bottom side.
8. It was then further progressed for Fill+Pack+Warp analysis :
9. Process Parameter setting for the analysis is as below :
   • Injection time: 1.2 seconds
   • Packing pressure profile:
     25Mpa for 0.2 seconds
     20 Mpa for 2 seconds
     15MPa for 2 seconds
     10 Mpa for 1 second
10. Result of the anaylsis is as below :

Fill Time animation is as below :

Warpage results are as below :

It can be seen that majority of warpage is found on the thin vertical walls.

Max warpage is around 0.7mm

Remedies to reduce warpage :

1. Use different resin or introduce additive to reduce shrinkage.
2. Provide stiffner to reduce the warpage effect on the walls
3. Provide cooling circuit for the mold