With reaction injection molding (RIM), chemical components, typically polyurethanes, are measured and mixed by metering equipment as they are injected into the mold. The components combine through a chemical reaction, and, depending upon the chemical formula, the end product can take on a range of characteristics: they can be either foam or solid, highly rigid or very flexible.
The RIM molding process provides numerous advantages over traditional injection molding. The "flowability" of the polyurethane components allows for even distribution of the material within the mold. This enables the production of large parts, said to not be possible with injection molding. RIM molding also allows for the encapsulation of inserts, such as metal frames. This capability has a broad range of applications, including PC boards. RIM also allows for the production of significantly varying wall widths. Additionally, the supplier says, RIM equipment is generally more automated, uses less energy to make a product and requires less equipment and floor space than injection molding.
The end product is designed to be low weight, scratch-resistant, high-strength, heat-resistant, and resistant to organic and inorganic acids. The R-value of polyurethanes alone is said to make it ideal for insulation in many products, including appliances. Other parts created through the RIM technology include medical and diagnostic equipment. Gusmer Decker, www.gusmer-decker.com
Gusmer Decker a Graco Co.