Points to note in LSR injection molding machine precision injection molding

Feb 20, 2020

There are many differences between LSR and traditional thermoplastic rubber processing. LSR shrinkage, demolding, mold materials, cold runner systems, and temperature control are very different from traditional thermoplastic materials, so this makes LSR More difficult to process than ordinary thermoplastics.

Because of the original metal or plastic components, the waterproof silicone ring of the LSR injection molding machine is generally smaller than the commonly used silicone ring and has higher compatibility with the shell and accessories, so it needs to be more accurate.

The key points of LSR injection molding machine to achieve precision injection molding are as follows:

Fully mix liquid silica gel with precise mixing ratio. Generally speaking, LSR is a two-component raw material of A and B. Before injection, it must be mixed uniformly according to accurate 1: 1. If it is a colored liquid silicone product, the proportion of color paste must also be accurately controlled.


The static mixer is a key part of injection molding. After the mixture is completely uniformly mixed, the A and B glues can only be completely cured and molded into the mold. Sealing and temperature control of injection molding machine parts

Due to the low viscosity of the LSR, it is necessary to consider the reflow and leakage of the material, and the screws must be sealed; the mold is heated during the SR forming process. In order to prevent the LSR from solidifying, a water-cooled nozzle can be used to ensure that the temperature is sufficiently low.

Finished product control during injection molding, dividing line: Pre-consideration of the position and accuracy of the parting line can help to avoid entrainment and welding air and avoid burrs; Shrinkage: Although LSR will not shrink during the injection molding process, due to its extremely high Coefficient of thermal expansion, usually 2% to 3% after demolding and cooling;