Injection Molding Cooling Problems

People in the industry all know that injection molding mold is a complicated step in processing. There are different views on cooling time after injection plastics are molded.

In injection molding, the accurate judgment of cooling time is not only related to the quality of the product, but also has a great relationship with the output and cost. The first consideration is to transfer the necessary heat from the plastic melt into the cavity to make it solid, so that it can be removed from the injection molding mold without deforming.Therefore, correctly budgeting the cooling time has become the first technical parameter that should be determined in injection molding.

So, what is the cooling time of injection molding? The cooling time is the time required for the molten material in the mold cavity to cool until the part can be removed from the mold. It is generally defined as follows.

1. The time required for the thickest part of the injection product to cool to the thermal deformation temperature of the polymer.

2. The time required for the average temperature on the section of the injection product to cool to a specified desired temperature.

3. The cooling time is the time required for the crystallinity of the finished product to reach a specified value, as well as the time required to cool the thickest part of the finished product to its melting point.

Injection products have certain fluidity which is controlled by adjusting injection pressure in injection molding.

The thermal function and cooling speed of injection products are different. The high thermal energy requires a lot of heat in the process of plasticizing, so it is necessary to adjust the injection molding machine with larger plasticization. The cooling time of injection parts with high hot deformation temperature is shorter and the mold is released earlier, so attention should be paid to avoid the cooling deformation after the mold is released.

It's of great importance to select appropriate cooling speed for various plastic products with different types and shapes. Additives of plastic products have different hydrophilicity. Hydroscopic plastics are necessary to adopt proper heating method to warm up strictly in accordance with requests, avoiding heat absorption again.