Quick Facts

Reaction Injection Molding, a foamed polyurethane molding process, produces parts with intricate detail, are dimension-ally stable, chemically resistant, physically tough, and wear resistant.   RIM's versatility and low tooling costs provide for economical prototype and short runs, while full scale production remains competitive with other processes.

The Process

Reaction Injection Molding (RIM) is the high pressure mixing of two or more liquid urethane components and the injection of this mixture into the cavity of the mold.  The liquids chemically interact, expanding the mix and filling the  mold.  Within seconds, the liquid solidifies and becomes rigid.  The resulting part is comprised of a urethane foam core sandwiched between tough, smooth skins of high density urethane at the surfaces. 

Reaction Injection Molding Advantages

Considerable design freedom is possible with thick and thin wall sections due to the uniform shrink characteristics.  Foamed polyurethanes are natural thermal and accoustic isulators.  Excellent flowability allows for the encapsulation of a variety of inserts.  Because RIM is a chemical reaction rather than a thermoplastic cooling and due to its inherent low molding pressures, even the largest parts remain stress-free without sink marks, regardless of the configuration.  RIM's versatility and low tooling costs provide for economical prototype and short runs, while full scale production remains competitive with other processes.  Since RIM urethane components are introduced as liquids, the inside of the mold is faithfully reproduced, making possible a myriad of applications from machine enclosures to marine products.

Tooling

A wide range of tooling materials may be used to produce RIM parts.  Among the materials used are silicone epoxy for "look see" parts, spray metal/ aluminum backed tooling when quick turnaround is required, cast and machined aluminum for low to medium production runs and good dimensional accuracy, and steel tooling for high production parts.