Finishing of Metal Calibration Targets
I would like some advice on how to finish some metal calibration targets (these are just metal bars). Our requirements are as follows:
1. Dimensions: 2" x 1/4" x 1' (up to 3').
2. Aluminum surface (only one side matters)
3. Aluminum surface can be machined or finished in whatever manner is required to make the best finish.
4. Finish requirements are:
1. Very flat (diffuse reflector) finish.
2. High degree of repeatability of color/gloss from one specimen to the next.
3. High uniformity of color/gloss across the piece.
Which type of finish would be recommended ?
1. Spray painting
2. Electrostatic powder
4. Other ?
- Delta, B.C., Canada
I'm not sure that I fully understand all of the parameters that you require, but I would probably brush finish, etch, and anodize them on the belief that an anodized finish is more durable than an organic coating. You could also silkscreen a very durable grid on them before anodizing, which might both serve the function of making them look like something and in some future iteration allow you to double-check a distance optically.
Ted Mooney, P.E.
Pine Beach, New Jersey
You may want to consider an abrasive blasting operation followed by hard anodizing. This would provide a uniform, non-reflective surface that is also abrasion resistant and electrically dielectric.Note: hard anodizing provides a black integral coating, especially on 6000 series aluminum
Fort Worth, Texas, USA
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