What should be Paid Attention to when Forming Transparent Injection Molded Parts?

As a Film Tapes Plastic Core Tube Exporter, share with you.

Due to the high transmittance of transparent plastics, the surface quality of plastic products must be strict, and there must be no streaks, pores, and whitening. Defects such as haze, black spots, discoloration, poor gloss, etc. Therefore, the raw materials and equipment are affected during the entire injection molding process.

The design of molds and even products must pay great attention and put forward strict or special requirements. Secondly, because transparent plastics mostly have high melting points and poor fluidity, in order to ensure the surface quality of the product, it is necessary to make fine adjustments at high machine temperature, injection pressure, injection speed and other process parameters, so that the plastic can be filled with mold without Internal stress will be generated which will cause product deformation and cracking.

The following is its preparation in raw materials. Regarding the equipment and mold requirements, the injection molding process and the raw material handling of the product, talk about the matters that should be paid attention to.
                              
                                                                                                               PE Plastic Tube Core

Preparation and drying of raw materials

Because any impurities in the plastic may affect the transparency of the product, and therefore storage and transportation. During the feeding process, care must be taken to ensure that the raw materials are clean.

In particular, the raw material contains moisture, which will cause the raw material to deteriorate after heating, so it must be dried, and the injection must use a dry hopper during injection. It should also be noted that during the drying process, the input air should preferably be filtered and dehumidified to ensure that it does not contaminate the raw materials.

Cleaning of barrel, screw and accessories

In order to prevent contamination of raw materials and the existence of old materials or impurities in the recesses of the screw and accessories, especially resins with poor thermal stability, therefore, screw cleaning agents should be used to clean each piece before use and after shutdown to prevent impurities from sticking. When no screw cleaning agent is available, resins such as pe, ps can be used to clean the screw.

When temporarily stopping, in order to prevent the raw materials from staying at high temperature for a long time and causing degradation, the temperature of the dryer and the barrel should be reduced, such as pc, pmma and other barrel temperatures must be reduced to below 160 ° C.

Mold design

In order to prevent poor backflow or uneven cooling caused by poor plastic molding, surface defects and deterioration, generally the following points should be paid attention to when designing the mold:

The wall thickness should be as uniform as possible, and the draft angle should be large enough;

The transition should be gradual. Smooth transition to prevent sharp corners. Sharp edges are generated, especially for pc products. There must be no gaps;

Gate. The runner should be as wide and short as possible, and the gate position should be set according to the contraction and condensation process, and a cold well should be added if necessary;

The mold surface should be smooth and low in roughness;

Vent. The tank must be sufficient to exhaust air and gases from the melt in a timely manner;

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