Polymers and colorants (masterbatches, etc.) are affected by temperature during the processing. Thermal stress is not only the result of processing parameters, but also that of the mold structure. An unsatisfactory mold structure may cause additional thermal stress, and the total of all thermal stresses will put the system within the range of initial thermal damage. To avoid this situation, the structure of the mold should take the following points into consideration.
① Gate system. The diameter of the gate should not be too small; otherwise, it will cause too much frictional heat. Another key point is the correct position of the gate.
② Mold cooling system. Polymers are poor conductors of heat. The cooling system should not only be effective but also ensure that the surface temperature at all parts of the mold is appropriate. Because uneven heat dissipation of the mold can lead to different contractions, which have an adverse effect on the quality of the formed parts; In addition, poor local heat dissipation of the mold can cause a significant extension of the cycle time, resulting in an increase in injection molding costs. The appropriate surface temperature of the mold is also important for forming a perfect surface of the formed parts, such as a glossy surface and the reproduction of surface structure.
③ The surface finish of the mold. All parts of the mold should have the same surface finish, including the cavities of all visible parts of the molded part, which should be made of the same alloy. Different alloys may cause different surface structures to be reproduced.
④ Good venting of the mold. This is very important for eliminating the black spots caused by the influence of diesel engines.
⑤ Sharp edges. Generally, sharp edges should be avoided as they may cause high shear force, which can have a detrimental effect on the quality of the formed parts.
⑥ "Dead point". Dead points must be avoided to prevent thermal damage to the polymer and colorant.
The selection of an appropriate hot runner can determine the function of the mold and the quality of the formed parts. Inappropriate hot runner systems often cause high pressure loss. If such systems are used, injection molding will be carried out at very high temperatures, which usually lead to the decomposition of polymers and colorants. Therefore, their use should be avoided. Hot runner structures should avoid sharp edges, "dead" points, and be too small in size. They should also have excellent temperature control.
Problems related to molds and hot runner structures are usually recognized in the test procedures. Whether the problems can be completely solved, of course, also depends on the type of problem, the time spent and the cost of solving it.
About UsThe company's main products include black and white masterbatches, colored masterbatches, and various functional masterbatches. It is mainly used in the plastic industry such as film blowing, blow molding, bag blowing, injection molding, sheet, pipe, wire, drawing, pelletizing, wire and cable, and modification of engineering materials.
ProductThe company's main products include black and white masterbatches, colored masterbatches, and various functional masterbatches. It is mainly used in the plastic industry such as film blowing, blow molding, bag blowing, injection molding, sheet, pipe, wire, drawing, pelletizing, wire and cable, and modification of engineering materials.
Industry applicationThe company's main products include black and white masterbatches, colored masterbatches, and various functional masterbatches. It is mainly used in the plastic industry such as film blowing, blow molding, bag blowing, injection molding, sheet, pipe, wire, drawing, pelletizing, wire and cable, and modification of engineering materials.
NewsThe company's main products include black and white masterbatches, colored masterbatches, and various functional masterbatches. It is mainly used in the plastic industry such as film blowing, blow molding, bag blowing, injection molding, sheet, pipe, wire, drawing, pelletizing, wire and cable, and modification of engineering materials.
Contact usThe company's main products include black and white masterbatches, colored masterbatches, and various functional masterbatches. It is mainly used in the plastic industry such as film blowing, blow molding, bag blowing, injection molding, sheet, pipe, wire, drawing, pelletizing, wire and cable, and modification of engineering materials.
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