Causes of burrs:
The material is under pressure and runs out of the mold gap, usually on the parting surface, affecting the appearance
How to improve burrs:
ONE. product design
1. Use materials with poor fluidity (such as PA is easy to run, PC is not easy to run burrs).
2. Parting surface: shrink the clamping surface by 2~3 strips to avoid the burrs caused by the deviation of the male and female molds on the appearance surface
Tow.mold design
1. The precision of mold processing and matching is improved, especially the friction surface of the slider, which is easy to run into the unilateral gap under the impact of material flow
Pay attention to machining accuracy, positioning method and matching accuracy
2. Strengthen the exhaust: avoid excessive local pressure, excessive filling and burrs
Safety depth of exhaust groove: PA 0.010mm PC/ABS 0.015mm PC 0.002mm
For materials that are prone to burrs, such as PA, the exhaust can be opened at the beginning of the runner, the position of the thimble and other non-appearance surfaces to solve the problem of burrs on the appearance surface.
Three. Molding conditions
1. Reduce the fluidity of the material: reduce the material temperature, mold temperature, injection pressure, and pressure holding (if it is inconsistent with the size, it can be set in sections)
2. Increase the clamping force
3. Reduce the gas generation of baking material, avoid the material being too high and cracking to generate gas, resulting in trapped gas, making the filling too full and running burrs
4. Appropriate switching position to avoid filling too much.
