: injection troubleshooter :

machine

· contamination

mould

· check sprue diameter
· pin-point too small
· poor venting

material

· melt too hot or too low, may create shear
· long residence time
· instability of polymer / pigments

1st

purge heating cylinder

2nd

lower material temperature by
- reducing cylinder temperature
- decreasing screw speed
- reducing back pressure

3rd

lower nozzle temperature

4th

check residence time

5th

check machinery purging

6th

shorten overall cycle

7th

check hopper and feed zone for contaminants

8th

check for proper cooling of ram and feed zone

9th

provide additional vents in mould

10th

move mould to smaller shot size press to reduce residence time