GMN Automotive was recently challenged by Fiat Chrysler (FCA) to develop a sill plate for the Jeep Durango. Initially, GMN Automotive approached FCA with a concept that matched the customer’s functional and visual intents, but after review, FCA decided their original design didn’t correspond with the rest of the vehicle. To create the necessary harmony, FCA revised their design to include the following requirements:
- Selectively finished (brushed vs. bright metal)
- Highly polished
- Crisp/clean graphics
- Performance driven
- Dent resistant
The two major challenges presented by this part were to find a metal material whose finish improved with electro polishing and plating, and to make sure the resistive ink – necessary to create a selective finish – would bond aggressively enough to the material’s polished surface to maintain the bright metal areas.
GMN Automotive was able to successfully meet all of the key design and performance requirements by utilizing a high quality material and a tailored construction of the part. A stainless steel alloy was employed because of its receptivity to electro polishing and plating, brilliance and lack of grain structure, superior corrosion resistance, and density for dent resistance.
To create the part’s selective finish, horizontal brushing was applied to the part’s surface, while the resistive ink protected the bright metal areas from being affected. An embossing stamp was created to raise the bright areas of the design and give the characters sharp, chiseled lines. After fabrication, the part underwent electro polishing to make the surface more uniform and enhance the metal’s brilliance. Finally, to address performance considerations, the plating process further enhanced the metal’s brilliance and sealed the edges of the part that had been cut.
This sill plate is representative of GM Nameplate’s continually expanding capabilities. The development of this performance-driven construction allowed for the creation of a product that was both visually striking and manufactured in the USA. This process also allows for stainless steel to compete with aluminum as they can now both be selectively finished.