| Dimensional Variations | |
| Possible Cause | Suggested Remedy |
| Non-uniform feeding of material | a. Adjust temperature profile for optimum feeding b. Increase shot size to maintain uniform cushion c. Replace check valve if cushion cannot be held |
| Large variation in cylinder temperature due to inadequate or defective controllers | Replace or calibrate controllers |
| Unbalanced runner system, resulting in non-uniform cavity pressure | a. Increase holding pressure to maximum b. Increase injection rate c. Balance/increase runner and gate sizes to provide uniform filling |
| Insufficient packing of part | Increase injection forward time and/or pressure to ensure gate “freeze off” |
| Regrind not uniformly mixed with virgin | a. Review regrind blending procedure b. Decrease percentage of regrind |
| Moulding conditions varied from previous run | Check moulding records to ensure duplication of process conditions |
| Part distortion upon ejection | See Part Sticking in Mould |