First, injection mold
1. If the mold cavity is not processed well, if there are scars, micro holes, wear, roughness, etc., it will inevitably reflect on the plastic part, making the plastic part poor in gloss. In this regard, the mold must be carefully processed to make the surface of the cavity Small roughness, polishing chrome plating if necessary.
2. If the surface of the cavity has oil stains, water stains, or too much release agent, the surface of the plastic part will be dark and dull. In this regard, you should remove the oil stains and water stains in time, and limit the use of mold release agents.
3. If the demolding angle of the plastic part is too small, it is difficult to demold, or the force is too large during demolding, so that the surface gloss of the plastic part is the best. In this regard, the demolding angle of the plastic part should be increased.
4. If the mold exhaust is poor, too much gas stays in the mold, which also causes poor gloss. For this, check and correct the mold exhaust system.
5. If the cross-sectional area of the gate or runner is too small or changes abruptly, the melt will be subjected to too much shear force when flowing in it, which will cause turbulent dynamic flow, resulting in poor gloss. For this reason, the gate and runner should be appropriately enlarged. Cross-sectional area.
Second, the injection molding process
1. If the injection speed is too small, the surface of the plastic part is not dense, and the gloss is poor. In this regard, the injection speed can be appropriately increased.
2. For thick-walled plastic parts, if the cooling is not sufficient, the surface will become fluffy and the gloss will be dark. For reason, the cooling system should be improved.
3. If the holding pressure is insufficient and the holding time is short, the density of the plastic part is insufficient and the gloss is poor. In this regard, the holding pressure and the holding time should be increased.
4. If the melt temperature is too low, the fluidity is poor, and it is easy to cause poor gloss. Therefore, the melt temperature should be appropriately increased.
5 For crystalline resins, such as plastic parts made of PE, PP, POM, etc., uneven cooling will cause poor gloss. For this reason, the cooling system should be improved to uniformly cool.
6. If the injection speed is too large and the cross-sectional area of the gate is too small, the vicinity of the pouring product will be dark and poor in gloss. For this reason, the injection speed and the cross-sectional area of the gate can be appropriately reduced.
Grandshine offers plastic injection molding for special project and OEM/ODM product solution.