If the mold cavity is poorly machined, such as scars, micropores, wear, roughness, etc., it will inevitably be reflected on the plastic parts, making the gloss of the plastic parts poor. Therefore, the mold should be carefully machined to make the surface of the cavity have a small roughness, and if necessary, it can be polished and plated with chrome.
If there is oil and water stains on the surface of the cavity, or too much release agent is used, the surface of the plastic part will become dark and glossy. Therefore, it is necessary to clean up the oil and water stains in time and limit the use of release agent.
If the demoulding tilt angle is too small and the demoulding is difficult or the demoulding force is too great, the surface gloss of the plastic part will be poor. In this case, increase the demoulding angle.
If the exhaust of the ABS injection molding mold is poor and too much gas stays in the mold, it will also cause poor gloss, and the mold exhaust system should be checked and repaired for this.
If the gate or runner cross-sectional area is too small or the sudden change occurs, when the melt flows, it will be subjected to a large shear force and present turbulent flow, causing poor gloss. In this case, appropriately increase the gate and runner cross-sectional areas.
If the injection speed is too slow, the surface of the injection molding supplies will not be compact, and the gloss will be poor. In this case, the injection speed can be appropriately increased.
For thick-walled plastic parts, if the cooling is insufficient, the surface will become hairy and the gloss will be dark. In this case, the cooling system should be improved.
If the holding pressure is insufficient and the holding time is too short, the density of the plastic part will be insufficient, and the gloss will be poor. In this case, increase the holding pressure and holding time.
If the ABS molding melt temperature is too low, the flowability is poor and it is easy to cause poor gloss. In this case, the melt temperature should be appropriately increased.
For crystalline resins such as PE, PP, and POM, if the cooling is uneven, poor gloss may occur, so the cooling system should be improved to make it cool uniformly.
If the injection speed is too high and the gate cross-sectional area is too small, the area near the gate of the mold will become dark, resulting in poor gloss, which can be resolved by reducing the injection speed and increasing the gate cross-sectional area appropriately.
The difference in the granularity of the raw materials makes it difficult to plasticize evenly and causes poor gloss, so the raw materials should be screened.
If too much recycled materials or sprue materials are added to the ABS moulding raw materials, it will affect the even plasticization of the melt and cause poor gloss, so the amount of recycled materials or sprue materials should be reduced.
Some raw materials will decompose and change color during temperature adjustment, causing poor gloss, so raw materials with better heat resistance should be selected.
If the content of water or volatile substances in the raw materials is too high, it will evaporate into gas when heated and condense in the cavity and melt, causing poor gloss. In this case, the raw materials should be pre-dried.
If the dispersibility of some additives is poor, it will cause poor gloss of the plastic part, so additives with better fluidity should be used.
If foreign matter, impurities or incompatible materials are mixed in the raw materials, they cannot be uniformly mixed with the original materials, resulting in poor gloss, so these impurities should be strictly excluded in advance.
If the amount of lubricant used is too small, the flowability of the melt will be poor, the surface of the ABS molding part will not be tight, and the gloss will be poor, so the amount of lubricant should be appropriately increased.