One, injection molding shell

1. If the mold cavity is poorly processed, such as scars, microholes, wear, roughness and other deficiencies, it is bound to reflect on the plastic parts, making the plastic parts poor luster, in this regard, it is necessary to carefully process the mold, so that the surface of the cavity has a small roughness, if necessary, polishing chromium plating.

2. If there is oil, water stains on the surface of the cavity, or too much release agent is used, it will make the surface of the plastic part dark and no luster, in this regard, the oil should be removed in time

And water stains, and limited use of release agent.

3. If the demoulding inclination of the plastic part is too small, the demoulding difficulty, or the demoulding force is too large, so that the surface luster of the plastic part is not good, in this case, the demoulding inclination should be increased.

4. If the mold exhaust is poor and too much gas stays in the model, it also leads to poor luster. In this case, the mold scheduling system should be checked and corrected.

5. If the cross-sectional area of the gate or runner is too small or suddenly changes, the melt is subjected to too much shear force when flowing in it, resulting in turbulent dynamic flow, resulting in poor luster, in this regard, the cross-sectional area of the gate and runner should be appropriately increased.

Second, injection molding process

1. If the injection speed is too small, the surface of the plastic parts is not dense, and the luster is poor, the injection speed can be appropriately increased.

2. For thick-walled plastic parts, such as insufficient cooling, the surface will be hairy and the luster will be dark, in this regard, the cooling system should be improved.

3. If the holding pressure is insufficient and the holding time is short, the density of the plastic parts is not enough and the luster is poor, in this case, the holding pressure and the holding time should be increased.

4. If the melt temperature is too low, making the fluidity poor, easy to lead to poor luster, in this regard, the melt temperature should be appropriately increased.

5. For plastic parts made of crystalline resins, such as PE, PP, PON, etc., uneven cooling will lead to poor luster, in this regard, the cooling system should be improved to make it evenly cooled.

6. If the injection speed is too large, and the gate cross-sectional area is too small, it will be dark near the pouring product and lead to poor luster, which can be appropriately reduced the injection speed

Degree and increase the gate cross-sectional area.