How to improve the brightness of outer appearance of ABS plastic?

How to improve the brightness of outer appearance of ABS plastic? China Plastic Mold Co., Ltd is going to explain to you.

1. Injection molds
Poor processing of mold cavities
If the mold cavity has defects such as scratches, micro-holes, abrasion, roughness, etc., they will inevitably influence the workpieces, making the workpieces have poor gloss. Therefore, the mold must be carefully processed to make the surface of the cavity has a smaller roughness. It should be polished and chrome plated if necessary.

Dirt on the surface of the cavity

If there are oil or water stains on the surfaclow of the cavity, or too much release agent are used, the surface of the plastic parts will be dark and dull. Therefore, the oil and water stains should be removed in time and the release agent should be used in a limited amount.

The demold angle of the plastic part is too small
If the demold angle is too small, it will be difficult to demold, or the force applied during demolding is too great, resulting in the surface of the plastic part not having the best gloss. Therefore, we should increase the demolding angle.

Poor mold exhaust
If the exhaust can’t let out well, too much gas will stay in the mold, and it will also cause poor gloss. Therefore, check and correct the mold exhaust system.

Improper gate or runner design
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. The turbulent flow is dynamic, resulting in poor gloss, so the cross-sectional area of the gate and runner should be appropriately increased.

Injection molding process
The injection speed is too low
If the injection speed is too low, the surface of the plastic part will not be dense and the gloss is poor. Therefore, the injection speed can be appropriately increased.

Insufficient cooling of plastic parts
If the cooling of thick-walled plastic parts is insufficient, the surface will be hairy and the gloss will be dark. Therefore, the cooling system should be improved.

Improper pressure holding operation
If the holding pressure is too small and the holding time is too short, the density of the plastic part will not be enough, resulting in poor gloss. Therefore, the holding pressure and holding time should be longer.

The melt temperature is too low
When the melt flow is too slow, the fluidity will be poor, and it is easy to cause poor gloss. Therefore, the melt temperature should be appropriately increased.

Uneven cooling of crystalline resin
For plastic parts made of PE, PP, POM, etc., uneven cooling will cause poor gloss. Therefore, the cooling system should be improved to have even cooling.

The injection speed does not match the gate area
If the injection speed is too high and the gate cross-sectional area is too small, the vicinity of the gate will be dark and has poor gloss. Therefore, you can appropriately reduce the injection speed and increase the gate cross-sectional area.

 

3. Raw materials
Great difference in raw material particle size
The great difference in particle size makes it difficult to plasticize the raw material uniformly, and the gloss is poor. Therefore, the raw materials should be sieved.

Too much secondary material in the raw material
If the recycled material or material from runner is added too much, the uniform plasticization of the melt will be affected and the gloss will be poor. Therefore, the amount of recycled material should be reduced.

Poor temperature resistance of raw materials
Some raw materials will be decomposed and their colors will be changed during temperature adjustment and cause poor gloss. Therefore, raw materials with better temperature resistance should be used.

The raw materials containing volatile matter
If the content of moisture or volatile matter in the raw material is too high, the raw material will volatilize into gas when heated, which will condense in the cavity and melt, resulting in poor gloss of the plastic part. Therefore, the raw material should be pre-dried.

Poor dispersion of additives
The dispersibility of some additives is too poor and the gloss of the plastic parts is poor. Therefore, additives with better flow properties should be used.

Impure raw materials
If the raw materials are mixed with foreign matter, miscellaneous or immiscible materials, they cannot be uniformly mixed with the raw materials, causing poor gloss. Therefore, these miscellaneous materials should be strictly excluded in advance.

Too little lubricant
If the amount of lubricant is too small, the fluidity of the melt is poor, and the surface of the plastic part is not dense, resulting in poor gloss. Therefore, the amount of lubricant should be appropriately increased. Therefore, auto parts manufacturers think it depends on whether the polish of your mold meets the requirements. If there is no problem with the mold itself, you must determine the characteristics of your ABS. You can choose high mold temperature, high speed and high pressure. Also, using chilling water can obtain smooth finishes.