: injection troubleshooter :

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plastic short shots

• 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@moldplast.com