CAD and CAM help shop pump out micromedical parts

The pacing leads provide the connection between the heart and the power source of pacemakers. In producing the cardiac leads, as well as proprietary ones for catheters and devices that introduce drugs into the body, Oscor Inc. of Palm Harbor, Fla. (oscor.com), does everything inhouse, from designing components, building molds, and micromolding parts, to sterile packaging and labeling. Typical part tolerances are 0.0002 in.

For design, Oscor uses PowerShape CAD software. "The program lets us build, repair, and modify surface and solid models," says Ed Smith, chief of manufacturing engineering. "And wizards let us extract cores, slides, and cavities straight from imported design geometry. PowerShape also lets us check draft angles, see hard-to-mold areas for the tiny leads, and inspect mold models for duplicated or missing surfaces."

To get fast turnaround, the company keeps mold bases on-hand. "We interchange components from the same basic mold, switching inserts in the base, vents, and carriers. The CAD program helps our designers generate time and cost-saving strategies to make interchanges smooth and the various mold assemblies reliable," says Smith.

The company machine shop cuts molds out of hardened steel on high-speed milling machines running PowerMill CAM software. It uses data from CAD models to generate code that tells the machine what to do. "PowerMill supports high-speed-machining (HSM) strategies for the efficient use of the CNC machine and the cutting tools," says Smith.

For instance, one HSM strategy involves keeping a consistent load on the tiny cutters, some only 0.005-in. diameter, and minimizing sudden changes in cutting direction. "This gives us high-quality machine surfaces in minimal time. Plus, the software lets us write our own code in, say, Visual Basic, to generate toolpaths that automate work such as the robotic handling of parts," adds Smith.