To solve the problem of injection molding flat parts, only 4 steps are required

The area of plane injection molded parts is large, and the shrinkage is large. Because the molecular orientation of large-scale injection molded parts is very serious, and the mold cooling is also uneven, the shrinkage of injection molded parts in all directions is inconsistent, resulting in the deformation and distortion of thin large plane injection molded parts. Sometimes one side of a large plane injection molded part is designed with a supporting bone. At this time, the injection molded part must bend towards the bone side.

It is really a difficult problem to solve the deformation of large plane injection molded parts. During production, we summarized some effective measures to improve the deformation:

1. Change the mold into multi-point water inlet (usually three plate mold), and the Hao of large plane injection molded parts with more than 24 a machine reaches more than 4 points. This can reduce the degree of directional arrangement of molecules and reduce the gap of inconsistent isotropic shrinkage.

Properly increase the mold temperature, and the ABS material is usually kept above 60 ℃ to reduce the cooling rate of injection molded parts, reduce the temperature difference deformation caused by chilling transition, and reduce the degree of molecular orientation.

3. The important thing is to increase the injection or pressure holding pressure and greatly prolong the injection or pressure holding time, so as to increase the size of the injection molded part, reduce its shrinkage and significantly improve the degree of deformation. Therefore, prolonging the injection or pressure holding time (e.g. 10 to 15 seconds) has become an important means to solve the deformation problem.

4. If none of the above three measures can achieve the ideal effect, only the method of mold setting is adopted. Because most people don’t use it very well, it needs some skills.

Summary:

First of all, the injection molded parts should be out of the mold early, and then, when they are still in the state of tens of degrees high temperature (it should still be hot, which is the key), they should be placed on the workbench and shaped with a fixture. The key is that the design of the shaping fixture needs to be appropriate.

At the same time, the springback degree of injection molded parts should also be considered. Usually, the springback will basically stop after 12 hours, and the lower the die temperature, the greater the springback. The so-called correction must be too positive, so the amount of over correction should be studied during production.