That’s a good point.
Well I’ve already made a lot of progress towards modding the printer so I’ll persevere but I’ll consider ways to mitigate the dust and debris problem. A vacuum attachment perhaps. vacuum pump
I’ve redesigned the hot end bracket to accept proper linear bearings instead of brass bushes. I bought the bearings on tatBay from China and could only get 12mm long bearings. The clips on the bracket are 8mm. I’m also designing a printed bracket that clips into the same “U” shaped slot as the hot end assembly to accept drilling and milling mechanism. This will have ball bearings to support a carbon fibre shaft holding the chuck and a flexible drive shaft driven from a motor mounted under the control board. There’s just enough space to mount this in a printed clip. It will drive more carbon fibre rods through a printed gearbox with a couple of bevel gears to the top of the rear of the printer. A hex drive will connect this to the drill head via the flexible drive.
Back to your point, drilling 0.5mm holes in PCBs will not create a lot of dust. Milling will create considerably more so perhaps I’ll abandon this idea. I was already toying with two potential methods of making the PCBs. One was milling away the 0.04mm copper surface around the tracks. The other is spray painting the surface then scribing the track layout (inverted) and using a chemical etch process to dissolve the exposed copper.
I can easily make a spring loaded scriber in a custom printed bracket to achieve this. Or perhaps simply use a ball head engraving bit in the drill chuck.
Another option is a laser to etch photosensitive coating on the copper clad board.