Just a quick tour of our chemical etching process
1. Design Advice
At all stages of the chemical etching process, our engineers at Photofabrication will offer advice both to improve the product and reduce the costs. We are able to view all types of data; from sophisticated CAD files to “back of a fag packet” sketches. Our metallurgist will advise you on the most suitable metal to use for your application. A wide range of metals and thicknesses are held in stock.
2. Receipt of Drawings
The customer sends data to Photofabrication either in the form of a drawing or an electronic file. This is converted using CAD to allow for the etching compensation and “stepped and repeated” to fit as many components as possible onto the film.
3. Film Plotting
This is then high speed laser plotted to create the Graphic Tool. Two tools are prepared; one for each side of the metal, which allows etching from both sides. Variances between the two tools can facilitate “half-etching” from one side.
4. Metal Selection
We carefully review the component usage to ensure that the correct metal has been selected both from a performance and cost perspective. Full traceability is maintained on all grades of metal, certificates are available upon request.
5. Metal Preparation
Before coating the metal with photosensitive resist, the metal is thoroughly cleaned to remove all dirt, rust, greases and oils. This allows good adhesion to the photosensitive resist to be obtained.
6. Resist Lamination
Photosensitive resists are UV light-sensitive polymers which are applied to the metal either as a liquid by dip coating or more usually as a dry film which is applied by hot roller lamination. The type of process used depends on the metal being used and the type of subsequent processing required. The coating is applied to both sides of the metal.
The Graphic Tool carrying the component image is now laid over both sides of the metal which has been previously coated with the photosensitive resist. The combination of Graphic Tool and coated metal is then exposed to UV light to transfer the image onto the metal coating.
The area of photosensitive resist which has been protected from the UV light by the Graphic Tool, remains soft and is then chemically developed away leaving the metal exposed ready for etching. The component image remains protected by the resist.
The prepared metal sheets are now passed through the etching machine to remove the exposed metal. Virtually all metals can be etched, although some are etched more readily than others. Photofabrication have a sophisticated etchant tank farm, allowing the ideal solution to be used to obtain the best quality. The etchant is regenerated to maintain a constant etch rate, lower environmental impact and improve economic.
The final process of PCM (Photo Chemical Milling) is to strip off the resist from the etched component and ensure that the metal is clean. A combination of automation and operator care is employed depending on the component specification.
11. Inspection and Packing
The components are checked electronically to ensure they conform to dimensional specifications and they are visually inspected for any surface defects. High quality finished products are then securely packed for overnight delivery.
If you think this chemical etching process can benefit you, please contact us or telephone 01480 226699.