Liquid injection molding (LIM) is an industrial fabrication process that molds materials into a broad range of components and products. Unlike the standard reaction injection molding process, which relies on pressurized impingement mixing, liquid injection molding uses a mechanical mixing process that focuses mainly on liquid silicone rubber (LSR) and similar elastomeric materials.
Choosing the right injection technology for LSR molding is key to a successful part, especially in the case of directly gated components (no sprue). The two most popular systems involve open nozzle systems and valve gates.
Modern LSR injection molding manufacturing reflects innovation and efficiency that are the results of decades of experience. Today, incredible cost-efficiency can be achieved without sacrificing time or quality, so long as one employs appropriate materials, selects a fitting manufacturing process and sets high standards.
For Two Shot Molding, a multi-shot mold is needed. There are several types of multi-shot molding available, such as over-molds, core-back, and multi-station molds. The right mold selection depends on part geometry, volume, quality, and molder capacity/capability.
For design and processing of Liquid Silicone Rubber (LSR) parts, in the silicone injection molding vulcanization process, the curing and respective flow behavior must be known. The two components begin to cure immediately after mixing. During curing the chemical bonds formed release heat which causes a temperature rise. Increasing the temperature of the resin decreases the viscosity, allowing better mold flow and exhaustion of air bubbles.