Seeing that we have CNC mills at VHS, I was thinking that I would like to use them for making PCB’s from copper clad.
I know that some members here say “Just order it online.” But it’s expensive to do it that way if you only need to use one copy, and it takes time to arrive. So I would do that if I were using multiple copies, or if it’s double sided and it would benefit from vias and plated through-holes.
But if anyone here knew how to do it, milling our own PCB’s could be useful for simple prototyping. You could design the board and get it milled, then solder the components, and if anything doesn’t work you could modify the design of the board and retry in the same day.
But I don’t know how to use the CNC mills yet, being new at VHS. I have only seen the one that’s straight ahead when you enter the front door (Is that the Taig or the Sherline?), and the big Grizzly which is obviously not the one to use for PCB’s.
Does anyone with CNC mill experience have a good idea of what the process would be to get the mill to make a PCB that was designed on the computer?
There is this guide on Instructables on this topic.
I wonder if the right answer is to have the ability to mill boards or if we should have a small set of equipment for chemical etching? I think we had some etching chemicals back at 45W but they were disposed of for lack of interest. Oh I know, a poll to gauge interest!
I would love to be able to etch or mill boards if we had the gear, a workshop tutorial, and it was safe and mostly mess-free. Otherwise ordering them from OSHPark is far more convenient for prototyping, and DirtyPCBs for larger/slower/cheaper runs.
The big reason nobody really has been pushing to do PCB milling or etching at VHS is that many surface mount components will make you hate life if you don’t have a soldermask on the PCB, and most of us use SMD almost exclusively these days. Between the mess, time required, and poor results of DIY PCBs and low cost and readily available professional PCBs, it’s really an easy choice as far as I’m concerned. If I have an urgent deadline and can’t get PCBs made in time, I’ll then use pre-made SMD breakout boards (basically PCBs with SMD footprints routed to pads) and regular protoboards for the wiring.
However having said that, I do have a full etching setup left over from when I used to etch my own PCBs, including heater, bubbler, and a bunch of paper specifically for toner-transfer. It’d need a laser printer to print on the toner transfer paper, but other than that it’s all there. I’d be happy to donate it to VHS, and run a class on the process at some point - though I don’t really think it’s something VHS will get much use out of which is why I haven’t done so already.
I did a bunch of etched boards, back in the day. I stopped when boardhouses
got really cheap, because it’s totally not worth it. Each of the processes
(export, printing, exposure, developing, toner transfer, etching - mix and
match depending on the process you go for) requires finetuning depending on
your particular batch of chemicals, so it requires a ton of
experimentation. Each time you run an experiment, setup and cleanup makes
the process take a couple hours. You won’t do it right the first time, or
second time probably.
My time is worth more than that, in what is essentially a dead process!
Milling would probably be easier and more consistent (albeit larger pitch),
and the Sherline is actually a decent machine for that! People used to do
it. If you want to turn it on a play around, go for it. Unlike the larger
Taig or the Grizzly CNCs, I don’t believe training is required. I can sell
you an engraving bit at cost, if you like.
Well, I suppose it was foolish of me to not expect this to become a “versus” thread. But too bad it happened so damn quickly.
But really; that poll isn’t even so relevant anyway, as this isn’t about a decision purchasing new equipment; I was talking about doing something with what we already have.
But since the original topic is already dead for now…
It’s too bad that more people voted for chemical etching. I’m afraid that the motivation is simply traditionalism, and fear of a less familiar method. But really; it makes sense given our situation here, as long as you’re not making anything really small.
Boardhouses use chemical etching because it’s better suited to large-scale production. It’s also the more common hobbyist method because it doesn’t require expensive equipment (like a CNC mill). But we do have a CNC mill; multiple actually.
Although chemical etching is better known, there are many steps involved. It also leaves you with chemicals that you must dispose of. This topic is often avoided by many internet tutorials on chemical etching, so I suspect that many people etching at home are going the illegal route. It would be nice to simply put the board under the mill, put in the right settings, walk away and come back to have a single-sided board with holes already drilled in precisely the right location.
Well, I didn’t consider that. But I suppose that would also apply when you drill the holes in a chemically etched board. This may be better suited to FR2 than FR4.
So chemical etching may be preferred over milling, because the tolerances
are much, much, better. I’ve successfully etched 0.65mm pitch footprints,
while your limit for milling won’t usually be much better than through-hole
sizes (0.1" / 2.56mm). Probably much less painful if that is acceptable to
you, though.
Yeah, that’s good. I like through-hole, and I don’t think I’m doing SMD until I have to.
I was just thinking that milling PCBs this way would be a good step up from perfboard.
Well that’s nice. I’ll figure out how to do that.
They have it on the Arch User Repository (AUR), so I can install it on Manjaro.
So I should just bring the G-code to the space, and then the rest of the steps I can deal with there, right?
I would recommend keeping these kinds of materials out of the metal cutting CNCs. Unless very strictly controlled the abrasive dust can be quite damaging to the machine. PCB milling is often done on dedicated router type machines that are more tolerant to dust.
It doesn’t look like he posted it on this thread, but a member here told me at the hackspace that the owner of the machine (I don’t know which CNC mill) has said that he won’t allow the machine to be used for this purpose.
Now that I think about it, I suppose that it could be nice. The only thing missing is that I would much prefer to do it with a printer that can print directly onto the copper board. The toner-transfer method is just too much hassle. I tried it repeatedly without success, although that may be because I used a colour printer (as it’s what I had access to).
It would be nice to have an easy way to make our own PCB’s at the hackspace. Some of us just want to get things done immediately, without spending much money. But it would probably be too much of a hassle if we can’t remove the steps of getting the toner onto the copper. It would also be good to make the drilling process easy and accurate, as it would take me a hell of a long time to get all the holes drilled out when I made a PCB at home. Laser cutter maybe? It might be dangerous as if the laser goes over exposed copper then it will get reflected (although this would be avoided by leaving the etch resist until after cutting, and trying to make it cut only where there is no copper).
By the way, I am sure that there are still many people that come to VHS who often solder through-hole.
I wouldn’t want to do that. I’m don’t use through-hole simply because I don’t have SMD parts, but because I like the construction method. Although I haven’t done it, I would imagine SMD being harder to solder with nothing to hold it in place. Using through-hole components for smd would take up more space than either through-hole or proper SMD. I would rather just drill holes.
I have struck gold when looking through the poisons locker (my first time searching through everything there, so some of you may already know). I have found positive photoresist.
I have never used photosensitive copper boards, as they’re too expensive. But I have heard about the process being more reliable than the iron-on method, even though it probably wouldn’t have the ease x quality of a direct print (if we had a printer that worked on copper).
Now I just need to find a printer to use that has transparent sheets.
Since it sounds like you are going to do this, here is my experience and knowledge (i had a full kit but i got rid of it)
transparent over head sheets for laser printers can be bought at staples
i got the best results with the toner transfer method by using paper specifically made for such use, it is high in starch and low in fiber content so it dissolves very easily in water.
-to transfer the toner properly you need the right pressure, temperature and speed. Other than using an actual fuser cartridge from a laser printer, you best bet is with a slightly modified laminating machine (right temperature and speed, pressure needs adjusting)
-etching, if you want good results with fine traces you got to keep the chemicals moving. You could use an aquarium pump to make bubbles, but i would sometimes end up with a bubble stuck to the board. … i ended up using a water pump from an aquarium filter, it lasted long enough for my purposes and they can be had cheap from Craigslist
-Oil is your enemy, wear clean gloves and clean the copper with a scrubbing sponge and isopropyl (99%)
-When designing the pcb i would fill large empty areas with copper (ground planes) so that the board spent less time etching and the chemicals would last longer
-be nice to the planet, neutralize and dispose of the spent chemicals in a safe manner
Having said all that, let me know if you would like some help. I think having a complete working pcb making kit at the space would be an asset
If I have an urgent deadline and can’t get PCBs made in time, I’ll then use pre-made SMD breakout boards (basically PCBs with SMD footprints routed to pads) and regular protoboards for the wiring.