Why Choose Photo Etching for Producing Metal Parts

The biggest problem with photo chemical etching is that it is unfamiliar to many designers and engineers. The second problem is that it has too many names: “PCM,” photo etching, chemical etching, acid etching, chemical machining, metal etching.  People don’t know what to ask for.

photo etched and gold plated leadframe

And just to add to the confusion, there are several other processes that sound similar, but aren’t the same.  Electrochemical etching is used for part-marking.  MetalPhoto is a photographic process for making nameplates that entails no etching at all. And, chemical milling is used to selectively alter three dimensional parts to change the surface or reduce the weight of the metal.

Photo etching is a metal fabricating technique that fits in a spectrum of processes that include metal stamping, CNC punching, laser and water-jet cutting  and wire EDM.  The end result of all of these processes is flat metal parts, that may be subsequently formed or finished by other methods. 

One of the chief advantages of photo chemical etching process is that photo etched parts do not acquire any thermal or mechanical stresses during fabrication.  The unwanted metal is dissolved by the etchant and rinsed away.

Stamping and punching are processes that require hard metal tooling to cut parts from sheets of metal which can cause cold working of the metal. Plasma, laser and water jet use narrow beams of focused energy.  In the case of the laser, the energy comes from colimated light, and the water jet uses a pressurized abrasive slurry, and plasma uses ionized gas.  Wire EDM uses a wire electrode to burn the parts out of metal.

Photo chemical machining is a relatively rare process.  There are only about 100 PCM shops in the country and barely a few hundred globally.  Compare that to several thousand metal stamping shops just in the US.  Photo etching is often a better solution to fabricating flat metal parts, but too few people are familiar with the process.  This video provides a 2-minute overview of the photo etching process: http://www.iplayerhd.com/player/ConardCorp

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