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 since I have all the photo exposure equipment and chemicals, but in reality I’ll just send away for them since they come fairly quickly, multi-layer and vias are possible and the boards don’t need drilling.
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
I have a cheapshit cnc mill I use for PCB milling. It does the job and once you get used to it, it goes fairly quick. Challenge is getting the board to stay flat, because if the tape lets go, now your bit is digging for China, and no board starts flat. Doing a height probe is very necessary. What I like is that I just swap the bit and run it through the drill map, then I’m ready to either drive rivets or poke a piece of wire through for my vias.
But for getting a quick prototype with vias and SMD pads, I don’t think etching compares. I’ll cut boards until I’m happy with the design then send it off to JLCPCB for a production board. I’m not precious about the dust, I run it out in the shop along with every other toxic gas and dust I deal with as a farmer. I guess you could run it outside if you were concerned.
This isn’t the kind of answer you wanted, but jlcpbc is beyond cheap if you have the budget for time. I’m getting 5 boards for less than $5 USD (coupon applied that lowered it by maybe $5). It’s made it so that I don’t have to think about chemicals for etching anymore. (I’ve done it a little but nothing recently)
I know but where’s the fun in that? I’ve ordered from JLCPCB a few times but it is a hell of a lot more satisfying when I’ve made the whole PCB myself.
Fair enough. My preferred battles are getting the MCU to respond the first time. It’s a great feeling when the supplies are up and you can read the id.
I think laser engraving is probably the best way to make them at home, although just buying from a pcb service like jlc is the best option if you can wait.
I have two laser heads, a 405nm 500mW and 450nm at 10W laser. I don’t think either of them are suitable for burning away copper but I can try that. I believe to burn away copper you need a pulsed YAG laser or something like that.
Yeah I think you would need to get a fiber laser, but it probably wouldn’t need much power.
I have heard of using diode lasers to burn off a mask for etching, though.
Yes I’ve tried that as well. It’s way better than messing with toner transfer or those etch resist foils/spray.
It also works well for solder mask. If you apply one white layer and a green layer on top of that you can make decent part labels by lasering away only the green top layer.