injection compression moulding/icm
The injection compression molding process is a combined molding technique of injection molding and compression molding. It is a method in which the melt is injected into a slightly opened mold cavity at a lower pressure, and then the melt in the injection mold cavity is compressed to further compact the melt, thereby improving the performance of the article.
Main Features:
Compared with traditional injection molding, the main feature of injection compression molding is that its mold cavity space can be automatically adjusted according to different requirements, such as it can close the mold guiding part before the material is not injected into the cavity, and the cavity space is expanded to twice the wall thickness of the finished part. In addition, according to different manipulation modes, the size of the cavity space can be controlled correspondingly during the injection of the material or after the injection is completed, so as to match the injection process, the polymer is kept under proper pressure, and to achieve the effect of compensating material shrinkage.
Compared with traditional injection molding, the advantage is that there is a larger proportion of wall thickness of the flow length, the clamping force and injection pressure can be reduced, and large parts can be made on smaller injection molding equipment, it also has lower material internal stress, and get good results on the refraction of light.
Mold Process:
According to the geometry of the injection molded parts, surface quality requirements, and different injection molding equipment conditions, there are four injection compression methods: sequential, synchronous, intermittent and selective.
Note:
It is necessary to select the inlet of the part to be injected and the position of the flow to the channel to achieve a good effect of filling the cavity;
The protruding guide rail and the guiding core and the cavity of the mold have a strict tolerance fit (0.02-0.04) to prevent the polymer from leaking out of the cavity. There need a nozzle with a Non-return switch to prevent the polymer from flowing back into the injection molding machine. It is also possible to install a hot jet nozzle with a check valve on the mold instead of the above nozzle;
For parts with through holes, the locking nails fixed to one side of the mold should be inserted into the other side of the mold with a good sliding fit to prevent the mold cavity movement from forcing the pin is loosen or become stuck;
In the ICM injection molding process, the cavity pressure is lower than that of the traditional injection molding, so the mold structure does not have to be as solid and bulky as traditional injection molding.
Case:
Injection compression molding is suitable for injection molding parts with curved shapes, such as laptop casings, car tailgates, car dashboards, and flat car fenders, CDs, ophthalmic lenses, etc.
