About PhotoChemical Machining (PCM)

What is precision photo chemical machining?

• A means of photofabricating thin gauge precision metal parts
• Metal thickness ranges from .001″ to .080″ depending on the type of metal
• Etchable Metals include many alloys of steel, copper, aluminum, molybdenum and more.
• Alternative to stamping, punching, laser, water jet and wire EDM
• Low cost tooling in one day
• Part sizes from .020″ diameter to 24″ x 60″
• Quantities from handfuls to 100,000's

Photo-Etching vs. Stamping, Laser, Water-Jet and Plasma Cutting

Many Names, One Process

Photochemical machining is known by a number of names including PCM, photo etching, chemical etching, and chemical machining. All of these names describe the same precision metal etching process. We use a stencil, which we call a photo tool, to expose multiple images of the parts on both sides of a sheet of raw material that has been coated with a light sensitive and acid resistant material, called “resist.” After the images of the parts have been developed, and the uncured resist washed away, we etch the metal around the parts by dissolving it in a ferric chloride solution. The resulting parts have no burrs or deformations of the raw material that can occur with other processes such as punching, stamping, and water-jet or laser-cutting.

The Six Steps of Photo Chemical Machining:

1. Clean the metal in dilute acid solution to remove oils and contaminants
2. Laminate photopolymer film on both sides
3. Print the part patterns onto the coated metal and expose the photopolymer
4. Develop the printed image to remove unexposed resist
5. Etch the metal in ferric chloride solution
6. Strip the resist in sodium hydroxide solution

The photo chemical etching process is frequently the process of choice because the tooling is inexpensive and can be produced very quickly, the parts are very precise and consistent, and the metal etching process is particularly effective when the shape of the part is complex and/or the part contains many holes or internal cut-outs. The Process Photo Tour

Popular Metal Alloys for Photo Chemical Etching

Photo etching is effective for many kinds of metal. Ferrous alloys (steel), aluminum, cuprous alloys (including copper, brass, bronze and copper nickel, beryllium copper and more), nickel and nickel-iron alloys, molybdenum and more are suitable for custom photo chemical machining services. Photo etched brazing alloy preforms are gaining popularity in aerospace and other industries. Popular Metal Alloys for Photo Chemical Etching