Size, geometry and cost constraints posed problems for design engineers at Gyrus Medical in Minneapolis MN, when designing the jaws for a single-use bipolar open-forceps surgical instrument that uses RF energy. Tight tolerances over the length of the part (about 4.5 inches) were also an issue. The instrument will only perform properly if the surfaces remain parallel. Gyrus looked at casting and machining before choosing metal-injection molding. "Any time we need that kind of accuracy, we're going to look for a MIM-molded part," says Craig Stowell, director of engineering for Gyrus Medical. Phillips Plastics developed custom ceramic fixtures to support the parts to eliminate sagging during the production process. The parts then went through a calibration process to meet final print specifications.
For more information on Phillips Plastics, go to http://rbi.ims.ca/4933-515.