Injection molded parts to the brightness
发布日期：2013-12-05 11:12:27 点击量：1568 信息来源：Creation
How can increase brightness plastic molded parts is the main reason of the bad lustre: mold, injection molding process, raw materials, etc.
One, the injection mold
1. If the mold processing, such as scars, microporous, wear and tear, rough, etc, is bound to response to the plastic parts, bad lustre plastic, and carefully processing mould, make the cavity surface has smaller roughness, polished chrome plated when necessary.
2. If the cavity surface oil, stain, or release agent to make too much, can make the dark, no luster on the surface of the plastic, and to keep clear of the oil and water damage, and limited use of release agent.
3. If the draft is too small, plastic demoulding difficulty, or ejection force is too large, poor surface gloss plastic, to this, to increase the draft.
4. If the mold venting is not good, too much gas stays within the model, also lead to bad lustre, to this, check and correct mold exhaust system.
5. If the gate or port area is too small or a sudden change, in which the melt flow when subjected to shear force is too large, the dynamic flow turbulence, lead to bad lustre, and should be appropriately increase the gate and port area.
Second, the injection molding process
1. If the injection speed is too small, not on the surface of the plastic is close-grained, bad lustre, to this, can improve the injection speed appropriately.
2. For thick wall plastic parts, such as insufficient cooling, the surface will be afraid of dark luster, the cooling system needs to be improved.
3. If the holding pressure is insufficient, the holding time is short, density and bad lustre enough plastic, that should increase the holding pressure and holding time.
4..If the melt temperature is too low, the liquidity is poorer, easily lead to bad lustre, and should be appropriately increase the melt temperature.
5. Crystallization for resin, such as PE, PP, POM, such as production of plastic parts, such as uneven cooling can lead to bad lustre, to this, should improve the cooling system, uniform cooling.
6. If the injection speed is too large, and gate area is too small, the water the product will be dark and bad lustre, near to this, can reduce the injection speed and appropriately increase the gate area.
Three, raw materials,
1. Raw material particle size differences, making it difficult to uniform plasticizing, and bad lustre, the raw materials for screening should be processing.
2. Reworked material or material floolwing add too much raw material, influence of melt uniformly plasticizing and bad lustre, to this, should reduce reworked material or material floolwing addition amount.
3. Some of the raw materials in the thermal control will break discoloration caused bad lustre, to this, should choose good raw material temperature tolerance.
4. High moisture and volatile matter content in the raw material, volatile into a gas when heated, in the mold and melt condensation, lead to bad lustre plastic, and dealing with the raw materials for dry processing.
5. Some poor dispersion of additives and bad lustre plastic, to this, should use additives with better flow properties.
6. Mixed with foreign body in the raw materials, sundries or combination of materials, they can't instead of raw material evenly mixed melt together and cause bad lustre, to this, should be strictly exclude the sundries in advance.
7. If too little dosage of lubricant, melt liquidity is poorer, not density on the surface of the plastic, makes bad lustre, and should be appropriate to increase the amount of lubricant used.According to your mold polishing degree meets the requirement, if the mold itself has no problem, make sure your ABS to determine the features, can choose the anti-embrittlement temperature, high speed and high pressure;Use chilled water to also can achieve smooth finish.
