Call me crazy but .... Would you see any issue with machining the copper off the back of the pcb with a cnc wood router? One could draw the circuit in their cad software and then "engrave" the unwanted copper away and drill the holes to feed your component leads thru? It would work for simple circuits, or if there is plenty of real estate available, for larger projects. Theoretically, it could be quicker and easier to assemble and solder the board than to do point to point wiring.
No nasty chemicals, or photoresist, or ....
No nasty chemicals, or photoresist, or ....
I've done this quite a few times.
The hardest part I've found is getting the PCB level so that the depth of cut isn't too deep. Sometimes one end of the board looks great, and the other end looks like the traces faded away!
I usually do larger spaces between the traces to allow for tooling. Small diameter mill bits break easily...
Most importantly though - dust extraction. You really shouldn't breathe the PCB dust so make sure that side of things is managed well.
The hardest part I've found is getting the PCB level so that the depth of cut isn't too deep. Sometimes one end of the board looks great, and the other end looks like the traces faded away!
I usually do larger spaces between the traces to allow for tooling. Small diameter mill bits break easily...
Most importantly though - dust extraction. You really shouldn't breathe the PCB dust so make sure that side of things is managed well.
There were $10k commercial machines for doing this back in the 70s.
As long as you don't need plated through holes and high resolution,
it's workable, at least for through hole parts.
As long as you don't need plated through holes and high resolution,
it's workable, at least for through hole parts.
As others have said, this is definitely possible. I have done it my CNC mill with great results. To help keep the board flat and parallel, I have mounted a sacrificial piece in the machine and then faced it off. Once you've done that the top surface should be dead nuts parallel to the machine. Then to hold the PCB down I use two sided tape. If your feeling fancy, you can mill some small open pockets on the perimeter so you can get flat head screwdriver under the PCB for removal.
Thanks
Thanks guys!
It’s nice to know that I get a viable “original to me” idea once in a while. Have a great day!
Thanks guys!
It’s nice to know that I get a viable “original to me” idea once in a while. Have a great day!
With the onset of very cheap Chinese PCB makers I no longer bother with DIY methods of pcb manufacture.
Today paid £1.57 for 5 100mm by 100mm pcb's.
Postage is a quite a bit more but still very cheap.
Today paid £1.57 for 5 100mm by 100mm pcb's.
Postage is a quite a bit more but still very cheap.
I agree.
If you are happy to wait a week or so and pay the postage, getting manufactured PCBs is the way to go. I get ten 100*100, 2 layer, through hole plated professionally made boards in my hands for around $40aud.
But for one-offs or quick prototypes, I find milling my own boards is a good alternative to chemical etching.
If you are happy to wait a week or so and pay the postage, getting manufactured PCBs is the way to go. I get ten 100*100, 2 layer, through hole plated professionally made boards in my hands for around $40aud.
But for one-offs or quick prototypes, I find milling my own boards is a good alternative to chemical etching.
Make vs buy -- there are services which render simple two-side PCB's very inexpensively.
For me, until I go in production, I will remake the PCB a couple times -- but sometimes with a Xacto knife and copper tape!
I did my first PCB for a ham radio receiver over 50 years ago.
For me, until I go in production, I will remake the PCB a couple times -- but sometimes with a Xacto knife and copper tape!
I did my first PCB for a ham radio receiver over 50 years ago.
Heh... I etched my first PCB when I was 12. I drew it on copper clad FR-4 with a DALO pen. A few years after that I stated using a photolithography method with negative photo resist and Kodak Lith film. I've stained more clothes with ferric chloride than I care to remember.
I still have my "garage fab". I now use the toner transfer method. That works pretty well down to ~15 mil trace width.
We used to have a small PCB milling machine where I used to work. That worked pretty well but couldn't provide much higher resolution than my garage fab. It worked similarly to the setup OP describes with the wood router.
I haven't touched the garage fab in 3-4 years now. I haven't used the dirt cheap overseas outfits. I prefer OSH Park in Oregon. The quality of their boards is excellent. They're not the cheapest but I sleep well at night knowing that the used process chemicals will be disposed of properly.
For those who are into surface mounted components, OSH Stencils is a great outfit. While many hand-solder SMD parts, using a reflow workflow makes prototyping such a breeze. I use a toaster oven for the reflow.
Anyway. To get to OP's question: Beware that FR-4 fibreglass is pretty hard on your cutting tools.
Tom
I still have my "garage fab". I now use the toner transfer method. That works pretty well down to ~15 mil trace width.
We used to have a small PCB milling machine where I used to work. That worked pretty well but couldn't provide much higher resolution than my garage fab. It worked similarly to the setup OP describes with the wood router.
I haven't touched the garage fab in 3-4 years now. I haven't used the dirt cheap overseas outfits. I prefer OSH Park in Oregon. The quality of their boards is excellent. They're not the cheapest but I sleep well at night knowing that the used process chemicals will be disposed of properly.
For those who are into surface mounted components, OSH Stencils is a great outfit. While many hand-solder SMD parts, using a reflow workflow makes prototyping such a breeze. I use a toaster oven for the reflow.
Anyway. To get to OP's question: Beware that FR-4 fibreglass is pretty hard on your cutting tools.
Tom
I have used Chinese fab JLCPCB for about a year now and done about 40 different pcb's.
Quality is excellent and never had any problems.
They are by far the cheapest.
They also do pcb assembly if you dont want to do it yourself.
Quality is excellent and never had any problems.
They are by far the cheapest.
They also do pcb assembly if you dont want to do it yourself.