Reaction Injection Moulding (RIM) is a process where a fast reacting PU (polyurethane) resin is low pressure injected into a mould. This process conveniently fits between Vacuum Casting and Thermoplastic Injection Moulding in the prototyping / manufacturing chain. This is a cold injection process that does not require pre-heating of moulds or post curing of castings. Larger sized components can be produced and several moulds can be cast consecutively, leading to quicker production times.
Tools are made from Silicone, Resin, Model Board or Aluminium, and can yield anything from 50 up to 1000+. This process is mainly used for larger and simpler parts with a typical wall thickness of 2-3mm+.
As with vacuum casting, a wide range of production simulant materials are available, offering a wide range of properties; rigid or flexible; solid or foamed, with a density as low as 40 kg/m³. Rigid self-skinning materials, where the surfaces are hard and solid enclosing a foam core, can be moulded to produce lightweight but rigid components.
Rigid and flexible RIM components are extensively used in:
- Exterior and interior automotive applications
- Large Machinery
- Domestic appliances
- Housings for electrical goods
- Medical
- Office furniture
- Sporting goods
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Advantages of Rim Casting:
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- Quick manufacture of tooling using RP technology masters or patterns
- Relatively low tooling costs
- Tough, durable, flexible and rigid components
- High quality and large component size
- High impact strength and dimensional stability
- Flexibility, low cost high or low volume production
- Inserts and metal reinforcement can be over moulded into components
- Good thermal, electrical and sound insulation properties
- Can be flame retardant to meet UL 94 V0 environmental compliance
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