If any injected part has been previously produced satisfactorily and it now goes wrong, something has changed. The main principle is never to change conditions immediately. The cause / reason should be identified and rectified.
Never adjust one condition to compensate for a failure or change in another condition. For example, if melt temperature has increased, don’t reduce speeds or pressures or mould temperature to compensate. Identify the problem, that is to say reduce melt temperature to what it was before, by checking and replacing thermocouples, etc.
Ask yourself questions:
- what has changed ?
- what is the fault?
- when did it start?
- how often does it occur?
- where in the part is the fault?
- is the fault randomly situated or always in same place?
Identify causes of defects:
- test, observe, conclude and study 'history of faults'
- injection speed: test
- screw speed: test
- back pressure: test
- melt temperature: test
- machine: check
- heating of cylinder
- mould temperature control
- material cushion
- locking of mould
So now let's use some method and solve the most common problems and issues that might show up when injecting plastic parts.
Some are due to the process itself, but some come from mold issues and even from part design. Go to solutions & problem solver page
Please take note that most problems should be addressed as early as when project design starts. Mold making also has a huge influence on the final part's look and usability as well as in the efficiency of manufacture and production.