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• Sticking in Cavity - plastic injection troubleshooter
• Description:
At end of cycle, the moulding does not release from the mould but sticks in the cavity (female mould side).
• Causes:
machine
· injection pressure too high
· injection speed too high
· holding time too long
· too much material feed
mould
· cavity too hot – release is better from hot mould (20°C below HDT)
· mould too cold
· poor mould finish
material
· melt too hot
• Actions:
1st
check cycle time: cooling
2nd
decrease injection pressure
3rd
decrease injection hold time
4th
decrease injection speed
5th
decrease second pressure time
6th
reduce and adjust feed for constant cushion
7th
check for poor mould finish or corrosion on mould surface
8th
increase mould opening time
9th
decrease material temperature by lowering cylinder temperatures and/or nozzle
10th
lower mould temperature
11th
adjust the cavity temperature to a 20°C differential between mould halves
12th
check mould for undercuts and/or insufficient draft and taper
13th
use proper mould release
contact:
jmfalcao@moldplast.com
