Chemical etching (also known as ‘photochemical etching’ and ‘chemical milling’) is a process for milling sheet metal using corrosive chemicals to selectively etch in specified areas. A number of manufacturing steps makeup the etching process, each requiring precise controls to produce a quality product.

The chemical etching process

As an overview, the chemical etching process can be broken down into the following key steps:

1. A sheet of metal is chemically cleaned to ensure that it is free from potential contaminants
2. The sheet is coated with a film that is resistant to the chemical etchant called ‘photoresist’
3. The pattern to be etched is overlaid on the photoresist covered sheet, which is then exposed to UV light. The area that is not covered by the etched pattern is activated by the UV light and this will prevent the acid etching the material in this area
4. The sheet is put through a development stage where the unexposed photoresist is removed, leaving uncovered areas which will be etched by the acid
5. Developed material goes through the etching process where it is sprayed with the chemical etchant to etch the required pattern into the metal
6. The material is cleaned to remove the remaining photoresist

The benefits of chemical etching

Chemical etching offers a number of advantages over mechanical machining including:

• There is no heat stress introduced to the material
• There is no burring of the material
• The mechanical properties of the material are unchanged
• The complexity of the pattern to be etched does not affect the cost of production

Heatric’s Langley Drive site is the largest chemical etching facility in the world (by volume of material removed). The facility utilises a range of dedicated equipment for chemical storage, cleaning, etching, and printing. Heatric’s capabilities allow etching of sheets in sizes up to 1500 x 600 x 3mm to etch depths of 2.5mm (and potentially deeper). Materials that can be etched include stainless steels (316L, 304L, Duplex) high nickel alloys and exotic materials such as 617.

For more information on Heatric’s chemical etching process, and to find out how Heatric’s expertise can support your project, send a message directly through the enquiry page or call Heatric on:

+44 (0) 1202 627 000