@analogoutput Description below of my anodised aluminium / CNC router method, adapted from an email sent to a friend a little while ago…
It took a while to figure out a good process for making the synth faceplate panels, but in the end I bought a load of 1.5mm thick black anodised aluminium from these guys (in the UK): http://www.impactmetal.co.uk/
To do the lettering I use a 0.4mm cutter, not a pointed engraving tool but fluted: https://www.mscdirect.co.uk/ACM-20000H/SEARCH:CATEGORY/product.html
The process is quite laborious, as the depth of the lettering has to be really accurate. First I machine an area of the MDF bed using a big 50mm diameter cutter, about 0.5mm deep, to make a flat area. I had all the anodised aluminium cut into 1m x 250mm strips (my synth modules are 222.5mm high), and one of these is then placed into the flattened area. The aluminium can be held in place with screws / penny washers and with aluminium bars with holes in the end, as well as the vacuum bed. Make sure the screws don’t deflect the aluminium at all.
The lettering is then machined to a depth of around 0.05 to 0.08mm (note that’s not 0.X, but 0.0X). Any less and the letters don’t show up, but any more and you get a burr and you don’t get nice shiny letters, and risk breaking the tool. I have to machine relatively small areas of lettering at a time (maybe 50 x 50mm) as the thickness of the aluminium varies over the sheet. I also have a suspicion that the hardness of the anodising isn’t perfectly uniform either.
If necessary, the Z axis in Mach 3 is updated if I’m cutting an area and the tool is a little bit high or low. So the tool might start off at 0.05mm but then need slight adjustment as it gets to the bottom of the panel. The trick is, though, to get the material really flat in the first place, as this saves a lot of time. If there is an accidental bit of burring, I smooth it over with a wooden lolly stick and re-cut the path to tidy it up.
Fine tuning the height is the laborious part, but I’ve found that resting a hand on the spindle or gentle pressure on the underside adjusts the tiny amount of backlash in the ballscrew bearings enough to correct the Z axis to make the lettering look good. I’m using a CNC router with 1220 x 1220mm bed by the way.
I have to sit with the machine as it does the lettering, and it takes roughly 45 minutes per 50mm panel width, but it’s surprising how you can get a few done in an evening, and they look great afterwards. Once the lettering is done, I change over to a 3mm cutter and machine two stripes at 0.15mm, cut the holes for sockets etc, and finally cut around the perimeter. This bit is a lot easier and the machine can be left unsupervised.
These single flute cutters are great, I use them for pretty much everything: https://www.cutwel.co.uk/milling/milling-cutters/alu-power-aluminiumnon-ferrous/1-flute-alu-power-carbide-end-mill-e5e47-series
Once the machining is done I file off the tabs, deburr the edges, then add a couple of strips of masking tape, which protect the face when the sides are folded in the folding machine.
PCB brackets are just cut with a 3mm cutter out of any 1.5mm aluminium sheet. Pots and sockets are added and tightened with Wera nut spinners. I’ve found the anodised panels to be really hard wearing, resisting scratches from dropped jack plugs etc. They look fantastic once they’re done, and it’s less hassle than this lengthy description might indicate, in that now and again I’ll re-make panels if I need to change the layout of a module or add an extra feature or whatever.
I think early Moog panels used bare aluminium lettering on a black anodised panel, which I only found out after settling on this method. Moog used some kind of industrial etching process though, rather than machining.
I’ve found this method works well, and if I didn’t have my CNC router that I use for other projects I’d definitely get a small one just for synth panels…