Decfects -

Description

Negative

Sharp separation, often jagged, often thru all or a majority of the section.

varies

Change in section or area restricted by features of the die or core. Defects often repeat in same location.

Visual inspection

Release of internal or externally applied stress

Area	Possible Cause	Potential Correction
Equipment	Out of calibration	See Best Practices Section
Equipment	Excessive Injection time	Decrease injection time. If pattern cools excessively in die, it will become hard and brittle and tend to crack before or during removal.
Equipment	High injection pressure pattern difficult to remove from die	Reduce injection pressure.
Equipment	Cold die	Increase die and /or platen temperature
Equipment	Improper mold opening	Slow down opening rate. Check opening sequence of die carefully without forcing pattern. Note: When draw is deep, make sure parting line is separated evenly. Add or extend guide pins.
Equipment	Improper removal of pattern	Check pattern handling and removal techniques. Consider using air assist
Equipment	Draft, burr or rough surface	Have tool maker check the die. Correct or polish as necessary.
Equipment	Improper adjustment of knock-out pins	Locate pins to avoid a bending stress on the pattern during removal and add more pins if necessary. Check adjustment of pins for even actuation and speed.
Equipment	Sharp inside corners	Check with engineering for possible addition of fillet.
Wax	Brittle wax	Consider changing wax to Increase toughness in order to reduce brittleness. Consult your wax supplier.
Other	Insufficient mold release	Check for adequate mold release in area of difficulty. Change mold release as necessary.