Polyurethane RRIM (reinforced reaction injection moulding) and RIM (reaction injection moulding) contends to plastics the title for preferred material in manufacturing external body parts for vehicles, such as bumpers, spoilers, rocker panels, fenders, etc.
Despite the higher cost, polyurethane prevails in terms of mechanical properties, cost of tooling, cost of processing equipment and time to market. Polyurethane is the preferred choice for medium-low volume productions (luxury and sports car) or for small series of high volume models.
RIM and RRIM polyurethanes are always injected in closed mould, using high pressure machines.
In both cases aid of nucleated air into polyol is important to ensure good flow of the injected liquid PU inside the mould (see Cannon’ solutions for air nucleation).
Processing RRIM is more critical than RIM, because RRIM features solid fillers, often abrasive, like glass or mineral fibers, carbon fibers and others. Thus, while RIM can be processed with a simple high pressure machine, RRIM requires machines with special dosing cylinders, provided with hydraulic piston.
Special treatments of the metal used for the mixing head ensure stable performance even with the toughest formulations.
Cannon supplies turnkey plants for exterior body parts working with RIM & RRIM