We are always curious about how we can improve the surface glossy of injection plastic parts, today we will analysis from 2 points: injection mold and injection technical.
1.Injection mold
Injection parts will not look good if the mold cavity has scratches, micropores, wear out, roughness, etc. As a result, we should process the mold elaborately, making the cavity surface smoother. It is possible to polish and chrome plate if necessary.
It is necessary to remove oil pollution and water stains in time and limit the use of demoulding agents if the surface of the cavity is oily, water stains or too many demoulding agents are being used.
De-moulding will be difficult if the draft angle of plastic parts is too small. If you overforce the demoulding process, the surface will be dull and non-glossy. For this project, it is necessary to increase the draft angle.
Excess gas is retained in the model due to poor mold exhaust, which also results in a lack of gloss. It is necessary to check and correct the die exhaust system in order to solve this problem.
When the gate or runner cross-section area is too small or changes suddenly, the shear effect of the melt in it is too high about the shear force when liquid melts in, resulting in poor gloss on the plastic part. In this regard, it is necessary to increase the gate and runner cross-sections.
2.Injection technical
Plastic part surfaces will be not compacted if the injection speed is too slow, resulting in poor gloss. This should be corrected by improving injection speed.
There are some problems with the thick wall plastic parts, including insufficient cooling, scared surfaces, and darker luster. The solution is to improve the cooling system.
It is likely that the density of the injection parts will not be sufficient and the lustre will be poor if the holding pressure and holding time are insufficient. This problem can be solved by increasing the holding time and holding pressure.
We should improve the melt temperature properly to fix this problem, as the melt temperature is too low, making fluidity poor and producing luster.m.
Plastics with crystalline resin, like PE, PP, POM etc., will have a poor glossy finish if their cooling is uneven. It is necessary to improve the cooling system in order to achieve uniform cooling.
Injection speed is too fast if the cross-section area of the gate is too small. There will be a lack of gloss and a dark color near the gate. It should reduce the injection speed properly and increase the section area of gate.