Program a machine that applies acid to precision-etch metal and plastic.
Makes wax pattern of ear and molds plastic impression of ear for use in hearing aids, using handtools, grinder, and polishing wheels: Forms red designing wax into shape of ear, using spatulas, brushes, and gas burner. Mixes ingredients to make plaster and pours it over wax pattern to form plaster mold of ear. Removes plaster mold from wax pattern. Mixes ingredients to make plastic compound and pours it into plaster mold to form impression of ear. Applies hot and cold water and air to mold to harden plastic liquid in cavity of mold. Removes rough casting of ear from mold. Grinds and polishes casting to obtain plastic ear impression, using electric grinder and polishing wheels. Examines impression for blemishes, and places it in box for shipment.