Machine specs aluminum plates

Good afternoon ,
I always wondered how the black and "white" aluminum plates found on various appliances (specs on electric motors, speed charts on lathes, etc) are manufactured.
I think it involves a silkscreening process, but I don't know how the black part is obtained (it' doesn't look to be a paint, more some black oxide, as it is tightly adhering to the underlying metal, with no discernable thickness).
If somebody knows more about the process, I would be happy to learn something new.

Massimo

Edited By Massimo Dalmonte on 10/12/2019 11:41:42

Take a look at www.gsmgraphicarts.com/ Massimo, the manufacturers appear to offer several different methods.

Brian G

Edit:  I just learnt (nearly 40 years too late) that the instrument manufacturer I used to work for had the wrong description on its drawings, and that the round head rivets that secure nameplates should be called drive screws, not drive rivets.

Edited By Brian G on 10/12/2019 12:58:14

It can be done like this.

Laser Engraving

skip to 3/4 of the way through if you dont want the layout process.

regards Martin

The coloured aluminium plates are produced by first anodising the plates. This is a protective surface which is porous, a bit like an open honeycomb on a microscopic scale. Selected parts are masked off, usually by photographic resist or silk screening. The part is then put in a bath of hot dye which soaks into the bare areas. The resist/silk screen ink is washed off and another part is left bare for more dye of a different colour. This can be done several times. An example is used on the speed control levers on older Colchester lathes.

**LINK**

Thanks everybody,
so the plates I was referring to are dyed anodized aluminum (always thought of color anodizing as covering the whole object and not only some parts of it...); it almost seem I could replicate this at home, using the same photoresist film used for pcb, though there is surely a learning curve to get decent results.

Massimo

Here's a link: **LINK**

It can be done, but my own efforts were 'inconclusive'.

Neil