Transparent plastic plates molding note _ plastic plates _ injection molding

Transparent plastic sign note transparent plastic molding with high light transmittance, will be strict in plastic sign products surface quality, without any markings, porosity, and white. Fog halo defects such as poor, black spots, color and luster, thus in the whole process of raw materials, equipment, mold, injection molding and the design of the product, will be very attention and strict and even special request. Secondly because of the transparent plastic more for high melting point, poor liquidity, so to ensure the surface quality of injection products, tend to be in high temperature, injection pressure, injection speed make minor adjustment to the process parameters, such as when making plastic injection can not only full of mold, and won't produce internal stress caused by the deformation and cracking products. So from the raw material preparation, the requirements for equipment and mold the aspects of raw material processing, injection molding process and product are strict operation. A, materials preparation and drying due to any impurities in the plastic, can influence the transparency of the products, therefore, and storage and transportation. Charging process, must pay attention to the sealing, ensure clean raw materials. Especially moisture is contained in raw material, after the heating will cause raw material deterioration, so be sure to dry, and in the injection molding, charging must use a drying hopper. Also note in the drying process, the input should be the best of air filter, moisture, in order to guarantee doesn't contaminate the raw material. Its drying technology, such as: the drying process of transparent plastic, material process drying temperature ( ℃) The drying time, h) Material thickness ( mm) Note pmma70 ~ 802 ~ 430 ~ 40 pc120 ~ 130 & gt; 6' 30 hot air circulation drying pet140 ~ 1803 ~ 4 using continuous dry feeding device is preferred. 2, cylinder and screw accessories clean to prevent pollution and in cavity has the old screw and accessories material or impurities, particularly poor thermal stability of resin, so, stop after application of the screw before using cleaner clean all parts, not with impurities, when there is no screw cleaning agents, PE, ps and other resin available cleaning screw. When temporary downtime, in order to prevent the raw material at high temperature for long time, cause solution, drying machine and barrel temperature should be reduced, such as PC, pmma, barrel temperature will drop to below 160 ℃. ( Temperature of the hopper for PC should have fallen to below 100 ℃) Third, in the mold design should pay attention to the problem ( Including the design of the injection plate product) Poor, in order to prevent back flow, or caused by uneven cooling of plastic molding, surface defects and metamorphism, generally in the mold design, should pay attention to the following: 1. Wall thickness should be uniform, the draft should be large enough; 2. The transition part should be gradual. Smooth transition, to prevent a sharp corners. Sharp edges produce, especially PC products do not have a gap; 3. Gate, flow channel, short and wide, as far as possible, and should be set according to the contraction condensation process gate location, should add cold slug well when necessary; 4. Mold surface should be smooth, lower roughness ( Below zero. 8) ; 5. Vent, tank must be sufficient, and discharge the air and the gas in the melt; 6. In addition to the PET, wall thickness not too thin, generally should not be less than LMM.