Anyone running CNC pcb prototyping?
- Thread starter Aurbo99
- Start date
I have thought of it.
The track spacing may be an issue with pcb milling. I'm still working through my Mach 4 & Ethernet Smooth Stepper setup.
Then I will need to test it on some board that I haven't created yet.
I'm still learning the ropes regarding CNC with my build. Low priority right now.
Choosing CAD software is another unresolved issue slowing me down.
Too many hobbies, ....
The track spacing may be an issue with pcb milling. I'm still working through my Mach 4 & Ethernet Smooth Stepper setup.
Then I will need to test it on some board that I haven't created yet.
I'm still learning the ropes regarding CNC with my build. Low priority right now.
Choosing CAD software is another unresolved issue slowing me down.
Too many hobbies, ....
I plan to try a different direction with CNC PCB production and go for a hybrid solution.
I have years of experience doing prototype PCBs using hand layouts and photographic techniques (drafting tape masters > Kodak ortho film > UV sensitive photo resist > ferric chloride etch). However, these days I have a CNC laser engraver in the house (a serious brand name machine I use for commercial work and not a cheap Chinese model) but I figure I can use the laser to selectively remove an applied acid resistant coating from the copper surface of a bare PCB and then do traditional etching of the laser prepared board (probably try the cleaner copper chloride in aqueous hydrochloric acid etch mix instead of the ferric chloride mix I used for years).
I have years of experience doing prototype PCBs using hand layouts and photographic techniques (drafting tape masters > Kodak ortho film > UV sensitive photo resist > ferric chloride etch). However, these days I have a CNC laser engraver in the house (a serious brand name machine I use for commercial work and not a cheap Chinese model) but I figure I can use the laser to selectively remove an applied acid resistant coating from the copper surface of a bare PCB and then do traditional etching of the laser prepared board (probably try the cleaner copper chloride in aqueous hydrochloric acid etch mix instead of the ferric chloride mix I used for years).
I agree. Way back...way way back...if you wanted a PCB you had to tape it out (Bishop Graphics anyone?), send it to a house, get the film and then a board, and it was $$$. Moved onto CAD, plotted the layout, but still needed to get film shot. So for one-offs and proto it was either wire wrap or copper clad and etch. I then found out my local PCB house (its nice to have at least one local to you) could do a print/plate/etch or what others call bare bones boards. No silk screen, you can get it plated or not...just copper. Basically what you have if you etch your own or mill it out. Pretty inexpensive way of doing it, and I will still do those on occasion for a fit test of oddball components. But now with the various PCB pools available, I personally do not find it advantageous to do a board myself. Its not a hobby for me, doing board layout, so if I do a board for me I often do a combine of several designs and $100 and a week later I have boards in hand. My software package? Eagle...I've been using it for over 15? years now, moved from OrCAD (when it was really OrCAD), Smartwork and red/blue tape.
Yes, I remember, back in the 80's we did that. The Drafting Department was responsible to do the artwork and tape layout. Us engineers got artwork usually 4X size on plotter paper to trace the artwork and compare it to the schematic. What a tedious process! There were usual mistakes in every project and if you didn't catch it the pcb board would have bugs in it, ... then back to the "taping" cycle, often wasting months.
Bishop Graphics. I'd forgotten that name. Chartpak I remembered, but needed a prod to recall the Bishop Graphics stuff. The only good thing I remember about the tape was that it was impossible to use in an un-airconditioned office/workshop in an Australian summer when it hit the high 30s/low 40s (Centigrade), and the tape couldn't be stored in those conditions either, so it justified getting an airconditioner fitted into the drafting area.
That's the reason we set up our own in house photo darkroom and PCB production area. Everything was done cheaply and unofficially. Even so, the home brew darkroom and etch tank meant that we could start with a drafting film board layout in the morning, and have the PCB etched and ready for drilling by lunch time ... it also meant that our engineers got into the habit of prototyping on double sided PCBs (no plate through facilities, so wire links and double sided solder had to do).
Our etch tank started as a silicon sealed, glass 2 ft x 1 ft x 1 ft aquarium heated with two tricked up fish tank heaters (thermostat was wound up as far as it would go) and some drilled PVC conduit connected to an old vacuum cleaner in blow mode as a bubbler/agitator in the bottom of the tank. We ran that for years. Had the odd incident ... like when the ferric chloride eventually seeped into one of the glass cased heaters, and the resulting electrical explosion blew out the side of the fish tank and hot ferric chloride went everywhere. Fortunately there was nobody in the area at the time. The occupational health and safety people would have shut us down in an instant if they ever saw our equipment.
Years later, we bought a commercial heated spray etch system to replace the aquarium ... but within just a few years, only the welded PVC case was left of the commercial system. Everything else in the commercial etcher failed in one form or another. The pump for the spray system just made it past the end of warranty. The replacement pump that we were assured was ""acid rated" and would work fine, lasted barely 30 minutes before the pump drive shaft disintegrated. We fitted a real acid rated pump with a magnetic drive and as far as I know, it's still running decades later. The special grade stainless steel cased heater lasted about 3 years, and we replaced it with a titanium cased heater. Over the years we learned that the only things that can hold up to hot ferric chloride are glass, titanium, some silicon sealants, nylon, and PVC. We had any metal fittings in the etch tank re-manufactured out of one of the "safe" materials.
I still come across old artwork, contact prints, and odd etched PCBs form my days there. I got very good at etching photographs onto pieces of PCB. I made stuff like etched aluminium wall plaques (got to be real careful etching aluminium in hot ferric chloride), and even etched steel fittings (would sometimes leave it in the etch tank over night to create the right level of etch). I miss having access to the facilities, but it certainly wasn't a healthy work place.