Continuing our exploration of the right molding process for part design (â€œDetermining the Right Molding Process for Part Designâ€), this blog entry considers RIM Molding vs.Sheet Metal
Sheet metal is a very low cost option for part production, but with this process you sacrifice manyÂ design features and often add piece counts to final assembly. RIM allows for much more intricate andÂ sophisticated form development compared to sheet metal.
Any features on the inner or outer surfaceÂ of a sheet metal part must be cut out, welded, or bolted on as a secondary process. With these featuresÂ molded into a RIM mold, you can reduce assembly, add value to the overall design, and ultimately lowerÂ unit costs.
Materials cannot be encapsulated in sheet metal. Only RIM canÂ encapsulate metals, electronics, and other parts for optimumÂ protection and strength. Both processes produce a high qualityÂ finish, but also take paint, silk screening and texturing well forÂ improved branding.
Sheet metal is the most cost-effective option for smallÂ production volumes, but RIM could be taken into considerationÂ if the part design is complex. While sheet metal tooling
turnaround is very quick, RIM Molding can incorporate features from production molds that require lessÂ secondary costs than sheet metal.
Up-front tooling costs of sheet metal are lower than that of RIM tools, and modifications to the designÂ can also be made at low costs. The trade-off is that many design features cannot be incorporated intoÂ sheet metal like they would with the RIM process, and non-rectilinear sheet metal parts become costÂ prohibitive in production.
Other Design Considerations: Using RIM molding will yield a much more attractive, sculptedÂ design that is lighter in weight and has better chemical resistance and insulation properties.