I mostly call it Photo Etching
Published by
Kathleen Stillman
on
How many names does it need?
As the Sales & Marketing person here at Conard, the three biggest problems I fight every day about what we do are these:
- The photo chemical machining process is not well known in the metal fabricating world and not at all in the knowledge base of solid modeling software;
- For the engineers and designers that could benefit from it, there is precious little information about etching in the wild; and
- The process has too many names!
It’s like a major case of multiple identity disorder: photo chemical machining, PCM, photo chemical etching, photo etching, chemical etching and chemical machining all refer to the same process.
As if that’s not enough, there are three additional, similar sounding processes that are NOT photo etching.
- Electro chemical etching (sometimes called electrolytic etching) is a process used for part marking on metal parts.
- The MetalPhoto process utilizes pre-treated aluminum panels to create nameplates and identification products.
- Chemical milling is a process used to modify parts by selectively removing metal from specific areas. Chemical milling is often used on airframe components to reduce weight.
Photo chemical etching is not subject to Nadcap because the etching process does not alter the properties of the material.
[Chemical milling may be subject to Nadcap checklist 7108/5. Nadcap (formerly NADCAP, the National Aerospace and Defense Contractors Accreditation Program) is a global cooperative accreditation program for aerospace engineering, defense, and related industries. Nadcap covers a range of special processes with uniform standards. ]
Finding a cup of coffee or a burger: easy. Finding an etching supplier: *crickets*.
Photochemical 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 about 2,000 metal stamping shops, just in the US. Photochemical etching is often a better solution to fabricating flat metal parts, but too few people are familiar with the process.
Etching is cleaner than people realize.
We also must overcome misperceptions about etching and the environment. Today, all-aqueous chemistries are used. PCM is closely monitored by environmental protection departments in every state where there are PCM shops. We take environmental responsibility very seriously. We have state of the art water treatment facilities. Our process waste water is cleaner than the municipal water supply. We must “clean” the city water in a de-ionizing column before we can use it in the etching process.
It’s surprising how often we receive inquiries from people who “want to buy a photo etching machine.” It’s not a photocopier.
Photo etching is a process that involves a considerable suite of specialized facilities and equipment. There are six operations performed by dedicated capital equipment. Our facility has a 5000-gallon spill-containment sump. We discharge an average of 4000 gallons of treated process water every day.
Photo etching is a metal fabricating process that fits in a spectrum that includes metal stamping, CNC punching, laser, plasma and water-jet cutting, and wire EDM.
The result of all these processes is flat metal parts. Stamping and punching are processes that require hard metal tooling to cut parts from sheets of metal. Laser, plasma and water jet use narrow beams of focused energy. In the case of the laser, the energy comes from collimated light, and the water jet uses a pressurized abrasive slurry. Plasma uses a beam of highly energized gas. Wire EDM uses a wire electrode to burn the parts out of metal.
Stamping and punching create mechanical stresses and burrs on the metal. Laser, plasma and EDM generate thermal stresses which may alter the characteristics of the metal.
Among the advantages of etching is that etched parts do not acquire any thermal or mechanical stresses during fabrication. The unwanted metal is dissolved by the etchant and rinsed away. We think of it as “stress free machining.”
Thousands of companies in dozens of industries rely on etched metal components.