Everyone knows that new products go through extensive design and prototype evaluation, as well as functional testing before they even see the light of day. Rapid Injection Molding is one of the best techniques for prototypes that need to undergo design changes during the development stage. It's a process that quickly turns out real parts and acts as the bridge between rapid prototyping and conventional injection molding. The technique supports almost all thermoplastics, including specially compounded materials. One Minnesota company is playing a part in radically reducing time to market by combining information age technologies with advanced moldmaking processes to deliver real parts, real fast, with real savings.

The Protomold Company (Maple Plain, MN) provides mechanical designers with a unique process to reduce their time to market: Rapid Injection Molding. Once associated with only straight-pull molding, Rapid Injection Molding now also accommodates up to four side actions per mold-a major advancement. Due to the original straight-pull limitation associated with their Rapid Injection Molding process, they developed the ability to automatically recognize undercuts in their customers' models, and these are still the most common part feature flagged as an issue by their system-if only to offer some potential cost and time savings if they can be removed. Sometimes, undercuts can easily be eliminated from the design without sacrificing functionality. For example, one technique used by Protomold is telescoping shutoffs to produce features that would otherwise require a side action in the mold. Telescoping shutoffs occur when two surfaces slide relative to each other as the mold opens and closes. When this happens, one or both mold halves will have projections designed to provide some desired geometry internal to the other half of the mold. But when undercuts are a required feature of a customer's design, Protomold offers support for certain classes of undercuts through the use of up to four side actions per mold, all of which must be on the mold parting line.

Even with the advancements noted above, the company has almost totally automated the process of producing the injection mold tooling. They work exclusively with CNC high speed machining in aluminum. No steel, no EDM, and none of the costly and time consuming custom engineering that normally goes into the development of the injection molds. According to Brad Cleveland, President and CEO of Protomold, the company's software automates the quoting and designing process, creating commands for their CNC milling machines to make the mold.

"Protomold's Rapid Injection Molding process combines 3D CAD technology with high speed CNC machining equipment to quickly manufacture injection molds," says Cleveland. "This efficient moldmaking technology enables the low cost creation of injection-molded prototypes and makes low volume runs of production parts affordable. Manufacturers and design engineers can get real injection molded parts or prototypes in just a matter of days and at a fraction of the cost of conventional methods."

Some Committed Protomold Users