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