Common sense of PET raw materials that need to be paid attention to in the injection molding process

December 31, 2021

一、Before molding, the plastic must be fully dried. After the material containing moisture enters the mold cavity, it will cause silver tape-like flaws on the surface of the part, and even hydrolysis at high temperatures, resulting in deterioration of the material. Therefore, the material must be pretreated before the molding process, so that the material can maintain the proper moisture.

二、Mold temperature setting：

1.Mold temperature affects the molding cycle and molding quality. In actual operation, it starts from the lowest appropriate mold temperature of the material used, and then adjusts it appropriately according to the quality situation.

2.Correctly speaking, mold temperature refers to the temperature of the cavity surface when molding is performed. In mold design and molding engineering condition setting, it is important not only to maintain a proper temperature, but also to make it uniform Distribution.

3.Uneven mold temperature distribution will lead to uneven shrinkage and internal stress, which makes the molding mouth prone to deformation and warping.

4.Increasing the mold temperature can obtain the following effects：

①Add the crystallinity of the molded product and a more uniform structure.

②Make the molding shrinkage more fully and reduce the post-shrinkage.

③Improve the strength and heat resistance of molded products.

④Reduce internal stress residue, molecular alignment and deformation.

⑤Reduce the flow resistance during filling and reduce pressure loss.

⑥Make the appearance of the molded product more shiny and good.

⑦Increase the chance of burrs on molded products.

⑧Increase the location near the gate and reduce the chance of recession at the far gate.

⑨Reduce the obvious degree of joint line

⑩Increase the cooling time.

三、Barrel Temperature

Although about 60~85% of the melting of plastic is due to the heat generated by the rotation of the screw, the melting state of the plastic is still greatly affected by the temperature of the heating cylinder, especially the temperature near the front of the nozzle-the temperature of the front is over When it is high, it is easy to cause dripping and wire drawing when taking out the parts.

The above is the Common sense of PET raw materials that need to be paid attention to in the injection molding process we have listed for you. You can submit the following form to obtain more industry information we provide for you.

You can visit our website or contact us, and we will provide the latest consultation and solutions

Share to:

Send Inquiry

Previou:How to troubleshoot the failure of the injection mold?-part7

Next:How to troubleshoot the failure of the injection mold?-part6