1. Injection mould
1. If the mold cavity of the vertical injection molding machine is not well machined, if there are scars, microholes, wear, roughness and so on, it will inevitably react to the plastic parts and make the plastic parts have poor gloss. To this end, the mold must be carefully processed so that the surface of the cavity has a smaller roughness. Finish chrome plating if necessary.
2. If the surface of the vertical injection molding machine has oil stains, water stains, or release agent too much, it will make the surface of the plastic parts dark and have no gloss. For this, we should remove the oil stain and water stains in time, and limit the use of the release agent.
3. If the moulding angle of plastic parts is too small, the demoulding is difficult, or the force is too large, the surface gloss of the plastic parts is not good, so it is necessary to increase the angle of the vertical injection molding machine.
4. If the mold exhaust is bad, too much gas stays in the model, which also causes the bad gloss. For this, the mold exhaust system should be checked and corrected.
5. If the cross section area of the gate or runner is too small or suddenly changed, the melt is subjected to too much shearing force when flowing in it, which results in turbulent dynamic flow, resulting in poor luster. Therefore, the cross section area of the gate and runner should be appropriately increased.
II. Injection molding process
1. If the injection speed is too small, the surface of the plastic parts is not dense and the gloss is poor, the injection speed of the vertical injection molding machine can be improved appropriately.
2. For thick wall plastic parts, if the cooling is not sufficient, the surface will be hairy and the gloss will be dim. For this reason, the cooling system of vertical injection molding machine 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 gloss is not good. For this reason, the pressure holding pressure and the holding time should be increased.
4. If the melt temperature is too low, the fluidity will be poor and the luster will be poor.
5. For the plastic parts made of crystalline resin, such as PEPP-POM, such as uneven cooling, it is necessary to improve the cooling system by vertical injection molding machine and make it cool evenly.
6. If the injection speed is too large and the gate cross section area is too small, the injection speed of vertical injection molding machine can be reduced and the gate cross section area can be increased.