What is Molecular Etching?
The commercial etching process found its feet with the advent of the modern printed circuit board (PCB) or printed wire board (PWB) in the 50s and 60s. The process involved laminating copper foil over a fibreglass substrate and selectively removing the copper by etching, to leave an electrical circuit.
Etching back the copper was a relatively easy erosion process undertaken using Ferric Chloride. This traditional chemistry has proved satisfactory for etching many other metals such as mild and stainless steels but as the need has arisen to etch more exotic metals, many of which are renown for their high corrosion resistance, a new approach to etching became essential.
Many etching operations continue by modifying the traditional chemistries, with somewhat less than ideal results while turning etching into somewhat of a 'black art'.
Advanced Chemical Etching (ACE) has adopted a radically different approach, designing and modelling the chemical reaction, or series of chemical reactions, and calculating the results…
Working closely with University of Wolverhampton in a Knowledge Transfer Partnership (KTP), ACE has developed new etching chemistries that are not only faster and more controllable but are safer to use.
Titanium, Aluminium and many of the so called 'superalloys' form a virtually instant oxide layer when exposed to air and this layer is invariably both hard and very resistant to chemical attack and erosion. (For chemical attack read etching!)
Titanium for example forms an oxide layer about 1-2 nm thick, but it will continue to grow to 25 nm thick in open air during four years time and the growth accelerates as temperature increases. A chemical agent designed to sever metallic bonds in Titanium is not necessarily the optimum agent to pierce the oxide layer. For this reason, the etchants developed by ACE for Molecular Etching are complex mixtures, designed, if necessary, to perform more than one task.
ACE Molecular Etching for Net Shape?
- High accuracy (±10% of material thickness)
- No burrs for subsequent removal (as in punching)
- No material stress (as in pressing)
- No requirement for tool wear compensation
- Ambient/low temperature process… no heat distortion or partial tempering (as in laser cutting)
- Built-in special features e.g. depth etch
- Economical from one to millions
- Low initial set-up and modification costs
- Single process
- Maintains material properties
- Produces net shape
A further benefit of Molecular Etching is that the chemistries have been designed to minimise exothermic reaction and thereby reduce any thermal stress to which the material might be subjected.
In the case of Aluminium Etching, post process metal can be recovered from the etchant, extending its life and making the process even more environmentally friendly.
Molecular Etching, although in its infancy, is already identified to be efficient, economical, safe and predictable… a process fit for the 21st Century that replaces a black art with proven science.
Please contact ACE today for additional information on our Molecular Etching capabilities.