To fabricate sheet metal components, photoresist and etchants get used. This is PCM or photochemical machining. It goes by the names photochemical milling or photo etching. Borne in the 60s because of the printed circuit board industry, photo chemical machining etching gives you complex parts with fine details. It gets used instead of punching, wire electrical discharge machining, stamping and laser or water jet cutting.

 

Photo Chemical Machining Etching

 

The process involves a mylar stencil that gets used for the images that will get made. Both sides of the metal sheet get coated with “resist”. After the development of the images, the uncured “resist” gets washed away. The surrounding metal gets dissolved through etching chemistry.

Photo chemical machining etching is effective in aluminum, copper, manganese, silver, stainless steel, titanium, brass, nickel, steel, zinc, brass and chromium. PCM gets used in producing precision parts like flex circuits, PCB circuit, rigid-flex circuit designs and decorative items like sheets and foils.

Uses of Photo Chemical Machining Etching

Specifically, photo etched materials get used in a lot of mechanical and electronic parts of many industries.

* In aerospace and defense – Metal components in the fuel systems, helicopter drive shafts, RF, space-rated batteries, fire detection and suppression systems, amoung others.

* In electronics and electricals – “Cans” are full metal enclosures where some electronic circuits get packaged. These get sealed with fitted lids which photo etching produces. DBC or direct bond copper which is done on ceramic, gets used in wireless communications, industrial, scientific and medical instruments and controls. Photo etching is the only practical way for DBC. Likewise, RF and its cousin, the microwave technologies use extensively PCM parts.

* Sensors – from smoke detectors, seismometers and strain gauges to mass spectrometers, to name a few.

* Mechanical – parts like gaskets, shims, shields, flexures, pressure membranes, clips, and apetures are products of photo etching. These parts are in lasers, turbines, PVD and CVD systems, printer, dispenser, and many more.

Pros of PCM

* It gives you quick production time because the PCM tool can get quickly made. Compared to hard tooling, prototyping cycles get reduced to days rather than weeks. The photo chemical machining etching cycle finishes within five days. New parts get done within 4 weeks and prototype orders get finished within 2 weeks. Secondary operations like forming, silk screening, addition of surface components, plating, heat-treatment and assembly need additional time.

* You get your tooling costs reduced. These inexpensive tools, in a matter of hours, can get generated and regenerated for revisions.

* You may work on complex designs because it’s very precise, flexible and gives consistent results. The raw material remains free of deformations. This isn’t possible with other processes like punching, waterjet or laser cutting or stamping. This is because PCM gives no stress on metals. PCM also leaves etched parts clean, free from contaminants.

* You may work on a range of materials. Photo etching suits metal gauges with a range of thickness from .005” to .065” for ferrous and non-ferrous metals and molybdenum.

Australian owned and operated, Mastercut, experts in thin metals is ISO 9001:2008 Certified. With 20 years to back them up, you can check out their products, services and projects in http://www.mastercut.com.au/services/pcm-etching.aspx

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