Design Features
Outside features in cast aluminum can be incorporated, but any internal features must be created through a secondary machining operation. RIM allows these features to be molded in for reduced assembly. Both methods allow for variable wall thickness—down to 0.60″ for aluminum casting, and from 0.125″ to 1.125″ in RIM.
Encapsulation
Materials cannot be encapsulated with aluminum casting. Only RIM can encapsulate metals, electronics, and other parts for optimum protection and strength.
Finish & Surfacing
Compared to RIM, the finish quality of cast aluminum parts is low; and RIM can take paint, silk screening and texturing better for improved cosmetics.
Volumes
Both processes are appropriate for small run volumes, but are typically not cost-effective when dealing with larger quantities (over 500/mo.).
Lead Times
RIM tooling lead times are shorter than for aluminum casting, and since Exothermic uses in-house machining centers, they can reduce processing and assembly time and create production molds within 2 to 4 weeks.
Tooling Costs
Both RIM and cast aluminum require a low up-front cost, although RIM is slightly more cost-effective if tooling modification will be needed.
Other Design Benefits
With RIM, you can create very large, light-weight, low-cost parts that would otherwise be limited in design with cast aluminum.