The pressure of the melt pushes the mold to open due to a too low clamp force.
On the parting line, the mold opens a little and the outcoming melt freezes and a flash remains.
The risk of the flash formation can be reduced by the use of a machine with a higher clamp force or the reduction of the specific pressure in the cavity.
Another reason for flash formation can be the wrong positioning of the touching surfaces at the parting line.
Injection molding defect: At the touching surfaces on the parting line it comes to flash formation.
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This glossary of plastic industry is provided by PLEXPERT Canada Inc.
