1、 Causes of flash
1-1 mould parting surface (PL) sliding surface does not fit.
1-2 injection pressure too high
1-3 injection machine offset
1-4 insufficient locking force
2、 Associated knowledge
2-1 mold parting surface PL, sliding mating surface, demoulding pin, cushion block, etc. All kinds of molds
The gap between grooves, if the flow of material becomes a flying edge. The flash is wedge-shaped. There is a tendency to grow.
2-2 the principle of eliminating the flash of products is generally to repair the die, which appears temporarily due to the bad setting of forming conditions
The temperature of the barrel should be reduced. Reduce mold temperature and injection rate, reduce material fluidity
Direction setting parameter of. However, it should be noted that the residual internal stress in the product will be caused by using this kind of material.
3-1 instant: reduce the injection pressure and the temperature of heating barrel. Reduce the ejection speed.
3-2 short term: grind the surface where the die has flash.
3-3 long term: the die is made of hard steel.
4、 Due to material differences
4-1 because the material with good fluidity is easy to produce flash, so the parting surface of the mold should be done tightly.
The viscosity of 4-2 crystallized material is very low during melting. In particular, the mold parting surface is required to be tight.
5-1 it should be noted that too much pressure on the mold will also cause flash, and foreign matters between parting surfaces will be damaged
If the die is damaged, the flash will occur again.
5-2 mold materials are usually S50C and other materials (Japanese jjs standard is equivalent to domestic 50 × steel)
It is difficult to produce flash on the parting surface of hrc30's pre hardened special steel