- molds and plastics  injection troubleshooter -

• Short Shots - plastic injection troubleshooter

• Description:

Resulting from incomplete filling of the mould: parts of the moulding are not formed.

• Causes:
machine · improper feed
· injection pressure too low
· injection speed too low
· injection time too short
· faulty back flow valve ring
mould · poor mould venting
· mould too cold
material · melt temperature too low
· viscosity too high

• Actions:

1st. increase dosage
2nd. increase injection pressure
3rd. increase booster time forward
4th. increase material temperature by increasing
cylinder temperatures
5th increase mould temperature, if glass-filled
6th check material flow length vs wall section thickness
7th increase nozzle diameter
8th check restrictions of nozzle, runners and actual gating
9th increase gate size of sprue and runner system

contact :  jmfalcao@webXpace.com

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