Actual melt and mold temperatures, actual fill time, injection pressures and times, back pressure, screw RPM s, cooling time, clamp tonnage, shot size versus barrel size. Brittleness Possible Cause Suggested Remedy 1. Melt temperature too low. Increase melt temperature. Material overheated, resulting in molecular breakdown.
Decrease melt temperature.
Residence time in cylinder excessive for size - use smaller barrel. Decrease overall cycle. Reduce back pressure. Contamination by foreign material or excessive pigment usage. Inspect resin for contamination.