Defects and solutions of transparent plastic parts formed by injection mold

Defects of transparent plastic parts formed by injection mold include silver lines, bubbles, poor surface luster, jarring lines, white fog halo and white smoke and black spots. The various defects and specific solutions are described in detail below. Of course, open plastic parts open mold injection can also contact us!

1. Silver grain: due to the influence of internal stress anisotropy in the process of mold filling and condensation, the stress generated in the vertical direction makes the resin flow upward orientation, and the refractive rate is different from that generated by the non-flow orientation. When it expands, it may cause cracks in the product.

Solution: In addition to the injection process and mold attention, the best product for annealing treatment. Such as PC material can be heated to 160℃ above maintain 3-5 minutes, and then natural cooling.

2, bubbles: because the water and other gases in the resin can not be discharged, or because of insufficient mold filling, condensation surface and too fast condensation and formation of "vacuum bubble".

Solution: Do bubbles only appear when the part is 85% full? If so, it may be an exhaust issue and need to check the exhaust channel and vent; Rib, ejector pin, nozzle tip and gate bushing poor fit, nozzle misalignment and hot runner separation plate and so on May be; Another source is the screw, more specifically the back of the screw. General purpose screws with 18/1 or lower L/D are most prone to this problem. Try using a lower rear area temperature or higher back pressure to solve this problem. Another solution is to vacuum the mold before injection.

3, poor surface luster: mainly due to the roughness of the mold, on the other hand, condensation is too early, so that the resin can not copy the state of the mold surface, all these make its surface produce small uneven, and make the product lose luster.

Solution: The cavity surface of the mold should have a good finish, preferably polishing treatment or surface chrome plating. Cavity surface must be kept clean, timely removal of oil and water stains. The variety and dosage of release agent should be appropriate; In order to increase the luster, can be appropriate to improve the die temperature, it is best to use the method of warm water in the mold cooling loop, so that the heat in the cavity fast transfer, so as to avoid extending the forming cycle, this method can also reduce the residual stress in the forming.

4. Seismic marks: refers to the dense ripples formed from the direct gate as the center. The reason is that because the melt viscosity is too large, the front end material has been condensed in the cavity, and the incoming material breaks through the condensing surface, so that the surface has seismic marks.

Solution: Increase the temperature of the barrel, especially the temperature of the nozzle, but also increase the temperature of the mold; The injection pressure and speed were improved to fill the model cavity quickly. Improve the size of runner and gate to prevent excessive resistance; Mold exhaust should be good, to set up a large enough cold well; Don't design the piece too thin.

5, whitening, fog halo: mainly due to dust in the air into the raw material or raw material water content is too large caused by.

Solution: When injection transparent products injection mouth white should be solved with open ice water rinse. PET material is very sensitive to temperature, as soon as the mold temperature rises, it will turn white. Therefore, it is necessary to open ice water during normal production. Transparent products have white spots because of cold glue into the product, or dust in the material. Increase the nozzle temperature, add cold feed well, keep raw materials to prevent dust from entering.

6, white smoke, black spots: mainly due to plastic in the barrel, due to local overheating and the formation of resin decomposition or deterioration of the barrel.

Solution: In order to prevent the black spot problem more effectively, it is best to select a few good quality and new injection molding machine specially used to produce transparent parts, and PC and transparent ABS and other hard adhesive transparent material and transparent PVC material separate to use the machine, can not be shared, dehumidification dryer to use air gun to blow clean, and then use raw materials to transport several times to achieve the purpose of cleaning this is very important.

The mission of Fanstar is to master the core technology of injection molding production, communicate and analyze the technology before mold production with customers from the production needs of finished products, so that the mold delivery time is short, the life is long, the mass production is fast and the finished product quality is excellent!以上翻译结果来自有道神经网络翻译（YNMT）· 通用场景