| Brittleness | |
| Possible Cause | Suggested Remedy |
| Melt temperature too low | Increase melt temperature (weak weld lines) |
| Material overheated, resulting in molecular breakdown | a. Decrease melt temperature b. Residence time in cylinder excessive – use smaller barrel c. Decrease overall cycle d. Reduce back pressure |
| Contamination by foreign material or excessive pigment usage | a. Inspect resin for contamination (replace if contaminated) b. Purge injection cylinder thoroughly c. Keep hopper covered d. Review material handling procedures for regrind usage e. Reduce filler or pigment loading |
| Excessive amounts of regrind | a. Reduce regrind % mixed with virgin b. Regrind level dependent upon application: general rule 25-30% c. Keep hopper covered d. Review material handling procedures for regrind usage e. Reduce filler or pigment loading |
| Injection rate too slow | a. Increase injection or first stage pressure b. Increase boost time |
| Improper gate location or size | a. Relocate gate away from potential stress area b. Increase gate size to obtain optimum filling |
| Moisture in material during processing | a. Review material handling to eliminate moisture pick up b. Dry material prior to moulding c. Utilize hopper dryers |
| Dry-as-moulded properties | Moisture condition parts to increase toughness |