The Reaction Injection Molding process utilizes low viscosity liquids, low processing temperatures (90 – 105 F°), low mold temperatures (90 – 105 F°), and low internal molding pressures 50psi and up.
The following are the major advantages of Reaction Injection Molding:
Very Large, Lightweight Parts
The flow-ability of the liquid polyurethane components allow for even distribution of the material within the mold allowing for very large parts. This is NOT possible with injection molding.
Varian Medical Accelerator
86.5" x 46.5" and only 40 pounds
Varied Wall Thickness
Producing significant variable wall thickness within the same molded part is achievable with RIM. Wall thickness ranges between .25 inches and 1.125 inches are possible cross-sections in the same molded part. This is NOT true for thermoplastic injection molding, blow molding, sheet molding compound and other polymers.
Lighting Unit
B-Side of an End Bezel for Lighting Unit
Low Tooling Costs
RIM tooling costs are significantly less than that of an injection mold. Because the RIM process incorporates low temperatures and low mold temperatures and pressure, the tool can me made out of less expensive mold materials such as cast aluminum. The choice depends on such factors as the number of parts to be made; dimensions, shapes, and tolerances; the quality and texture of the surface; mold life; required mold cost; and part performance
Freedom of Design
RIM allows for complex mold shapes or highly detailed parts with intricate design features.
Door for Telecom Cabinet
Fountain
Encapsulation of Inserts
Different types of inserts and be placed into a mold prior to injection of the RIM material, and the RIM material can encapsulate many inserts during molding. Inserts such as steel, aluminum, glass, wood, electronic sensors, PC boards and wiring harnesses are some examples of material that have been encapsulated.
Steel Plate Encapsulation
Rapid Prototyping
Working prototypes can be developed with short lead times and the RIM process is ideal for shorter production runs of less than 5,000 parts.
Class – A Surfaces
The surface finish of RIM parts allows manufacturers to produce Class A painted parts.
Toro Commercial Equipment
Toro Tractor Shield
In-Mold Painting
With the RIM process, it’s possible to apply gel-coats and two-component polyurethane in-mold paints into the mold prior to injection. The injected polyurethane material bonds to the gel-coat or paint during molding, allowing a decorated part to be produced in the mold. This can significantly reduce secondary finishing costs.
Other Benefits
High strength, scratch resistant, heat resistant, impact resistant, resistant to organic and inorganic acids, and high R Value.