The RIM procedure uses really low viscosity liquids as from 500 to 1500 mPas, low mold temperatures of between 30 to 40°C, low internal molding pressures of 3 to 10 bar and low processing temperatures of 30 to 40 °C. The low temperatures, low pressures and low viscosity offer some very unique advantages or benefits for the reactive injection molding process in comparison with what’s obtainable with other plastic processing methods.
- Very Large Parts
The flowability associated with the liquid polyurethane components lets them fill molds for huge parts. The inflexible structural foam roof for a Company & Deere combine weighs around 250N and measures 1550 mm by 1700 mm. The bulk of the part that could be molded is dependent on the throughput of the metering unit as well as the speed of the reactivity feature of the polyurethane formulation- the pounds per minute that could be dispensed.
- Encapsulation of Inserts
Inserts of several types could be placed into a mold before the injection of the RIM material. And the RIM material could encapsulate several inserts while molding takes place. In one instance, an aluminum frame is put into the mold and an elastomeric Reaction Injection Moulding (RIM) system is injected and encapsulates the frame thus forming the decking for a snowshoe. PC boards, window glass, wiring harnesses, aluminum frames and shapes, glass performs, steel and electronic sensors are a few examples of materials that have been encapsulated with the help of the RIM process.
- Thick and Thin Walls
Producing variable wall parts within the same molded part are a major issue with a lot of plastic processing materials and methods, like blow molding, sheet molding compound (SMC), thermoplastic injection molding as well as other polymers. However, the reactive injection molding procedure provides you with the flexibility to create parts with major variations in wall thickness. Wall thickness that is between 6 mm and 30 mm are likely cross-sections in the same molded section.