Which do you prefer? I have the option to do both but milling seems to take awfully long and produces a lot of noise and glass fiber dust. It has the benefit of not needing etch resist which is also messy.
Chemical etching with iron chloride is also quite messy. First applying etch resist, removing part of it, etching etc. It is much simpler though and you don’t need a CNC machine for this.
Chemical etching is more accessible for sure, but every part of the process kind of sucks. Getting a solid toner transfer, preparing the bath, keeping the bath warm /moving, evenly washing the board (and stopping at the right time), cleaning up the mess, drilling all the through-holes, and optionally tinning… It’s all labor-intensive and error-prone, and I’m honestly not sure if the results I got would ever have been good enough for modern digital circuits. Ymmv.
(If I did go back to chemical etching, I sure as hell wouldn’t use ferric chloride. I’d try one of those reagents you can actually see through!)
Hmm. I’ve gotten to the point where I used my CNC for the chemical etching process as well. Instead of fumbling with toner transfer I use spraypaint and a laser engraver as etch resist. It is way more reliable.
As for ferric chloride, indeed you cannot see your circuit board but it is possible to store this for long. Solutions like HCl + H2O2 don’t last very long and I only do PCB making sporadically.
This is basically what I do at the FabLab, I was about to post a comment when I saw yours. If you’re interested, I wrote a blog post on the procedure, what I need to update it for double sided PCBs https://emamaker.com/projects/fablab/pcb-laser-engraver.html
Interesting read! I’ve seen a video on youtube where someone used white UV curing resin as the first layer and also as etch resist. It can be cleaned with IPA and you just leave it on after etching.
Afterwards a green layer of UV curing resin is applied and the laser is used to burn away only the green material so that silkscreen text becomes visible. I haven’t tried it myself but it looks like a promising process.
Yeah I know about that kind of approaches but I haven’t been able to test them, the resins don’t look cheap and I don’t make pcbs often enough to justify the cost. But I have tried engraving FR4 to get silkscreens on single sided boards. Decent results, but the smell is awful