RIM vs Cast Aluminum

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RIM offers

Better Finishing Quality

Lower Lead Times

than Cast Aluminum

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.


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.


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.

Though these are some of the main considerations to account for when deciding on a production process, there are many issues to balance when determining the most effective option. Let Exothermic help you uncover the opportunities for success and guide your design concept to meet those process needs.

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