Prototype tooling gets grainyPrototype tooling gets grainy

Akron, OH -Without the ability to texture plastic parts, non-metal rapid tooling could have an even rougher time competing against aluminum or steel than it already does. But now a new process from Akron Metal Etching Co. may just give "soft" tools the finish they need.

Called Prototex, this patent-pending process can impart more than 2,000 standard and custom mold finishes to tools based on stereolithography (SLA) parts. The process, which actually textures a photosensitive polymer that coats the entire SLA part, has two key steps: First, a photographic image of the desired finish is projected on the part, selectively curing the coating. Then, a chemical etching removes any uncured coating. As Akron Metal Etching President Lee Eisinger explains, "The finish is actually built up in relief," with a depth ranging from 0.0005 to 0.015 inches deep.

Once textured, the SLA part can serve as a master for "soft" tools capable of turning out aesthetically-and functionally-accurate prototypes. In a recent job, for example, Applied Rapid Technologies (Fredericksburg, VA) used a textured SLA part to create a silicone-rubber tool capable of producing cast urethane prototypes.

Among the couple thousand available finishes are standard matte, leather grain, complex geometric patterns, and logos. Eisinger also notes that Prototex has achieved a growing success with difficult multilayer finishes as well.