Interpretation of the causes of burrs in injection molded parts
automotive aluminum die casting shows the remaining plastic appearance, mostly in the mold clamping, thimble, slider and other moving parts, which is a major problem for poor molding. Many products simply have burrs, which may be OK during mold testing. There will be after a long time. There are roughly the following types of hair edges of injection molded parts:
1. This kind of thin-walled product is back-filled in sequence, and the pressure is very high when filling at G1. Usually, there are burrs during filling, which is not caused by subsequent pressure maintenance.
2. Moreover, the environmental protection material of ABS+28PET is used, and the poor fluidity will also cause the pressure at G1 to be too large to support the mold
3. The heat dissipation holes here are very easy to have punch marks (ABS is good, ABS+PET is not), and the molding technology that requires high mold temperature and speed can be adjusted better, which makes the pressure backlog at G1. Delay the injection speed, decrease the injection pressure, decrease the holding pressure, slightly accelerate the V-P switch, and check the clamping force.
4. If the mold is to accelerate the curing of the resin, it is to add cooling water, check the parting surface of the mold, and close the mold to see if there is any dead land.
When the temperature of the master mold reaches 75 degrees, the burrs have extended to the sidewall where the side wall is scratched, and then the temperature of the master mold is lowered to 60 degrees, and the burrs have been effectively improved, as long as they are very small, but they cannot be completely eradicated.
In fact, when we usually make such products, we usually scratch the vicinity of G1, but here the heat dissipation hole can only be scratched on the side wall, and the front can only be scratched, so it is easy to support the burrs, so change the Only by scratching can we completely solve this problem
Of course, the plastic car parts manufacturer increases the thickness of the meat by 0.2mm, the thickness of the meat is thicker, and the material is changed to ABS with better fluidity, so there will be no such question. Regarding the burrs of the product, sometimes the mold temperature is required. High talents can improve the burrs, and sometimes the opposite is true. Everything must be analyzed from the actual product, and only after understanding the reasons can effective countermeasures be made.