Photofabrication Engineering Inc., manufactures tight-tolerance metal parts precise enough and light enough for use in hearing aids, in semiconductors, in medical implants, in fuel cells, in microelectronics and in defense work.

To create the part, a customer provides PEI with an image. From that image, PEI creates a photo tool by covering a metal sheet, top and bottom, with a photo resist coating. The customer’s image, the shape and details of the desired part, is then transferred onto the sheet with ultraviolet light.

“Because photo tools do not wear like standard metal tools or molds, every part — from the first to the millionth — is the same; once it has been established that an etched part meets the customer’s criteria, all of those parts will meet those same criteria,” PEI’s website said.

In addition to industrial uses, PEI also produces decorative items, commemorative gifts, holiday ornaments, custom jewelry, business cards, and mementos.

That UV step leaves the sheet with a protective coating where full metal thickness is desired, but no protection in areas desired to be removed. Then the sheet is exposed to chemistry on a conveyor that etches away the waste metal. Once the desired shape is reached, the remaining emulsion is stripped from the metal. The part is now ready for the next manufacturing steps, which could be assembly, plating or cut-off.

PEI uses UV light and a chemical process to precisely shape a wide range of metal, including aluminum, beryllium copper, brass, bronze, copper, gold, Kovar, magnesium, mild steel, molybdenum, nickel, nickel iron, pewter, phosphorus bronze, silver, stainless steel, tin, titanium, zinc and zirconium. Metal can be shaped in thicknesses from 0.0005-inch to 0.1250-inch. Tolerances depend on the metal thickness and the feature being etched, and can be as tight as 0.0005-inch. PEI meets numerous international quality requirement standards, including AS 9100 for aerospace; ISO 13485 for medical, ISO 9002 for general manufacturing, and Mil—1—45208 for military specs.

This chemistry, UV combined with a photo-resist process, was originally used to create rifle reticles (crosshairs) in the early 1940s, and now many industries use it, or any industry that needs smaller, lighter, more precise metal parts. PEI was founded in 1968, and expanded in 1984 into its present 40,000-square-foot facility in Milton, Massachusetts. For more information about Photofabrication Engineering Inc., visit