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Laser printers + 3D Printer. Easiest route to home etched/cut PCBs?
Posted by paulca on 05 Mar, 2023 09:52 -
So I hate protoboard. The only time I will use protoboard is when there are only a handful of components. Say a power distribution board in a multi-module lash up. Once you start with dozens of components and traces, its just too time comsuming and fiddly and using the green plated through hole versions, it's next to impossible to fix mistakes or get components back.
I do like PCBs. I just don't like the long (2-3week) lead time, the cost (when you include shipping to get it inside of 6-12 weeks). For me this tends to make me iterate and tweak and try and perfect each PCB I send for manufacturing. This elongates the process.
So I'm again looking at what options exist for an interim PCB made at home.
I did a little you tube watching last night and arrived at a few ideas.
1. Laser print positive onto paper. Heat transfer toner to a blank. Etch with copper chloride or whichever is easiest to order without a chemists account.
2. PCB resist print with 3D printer... etch as above.
3. Similar to above but with negatives and UV setting pre-resist coated blanks.
4. CNC approach using the 3D printer and a milling head + end mill.
On my travels I found something pretty cool. Creality make a 5W laser head for my printer. That will cut 3mm ply pretty easily. I'm going to imagine it reflects off shiny copper, so dangerous, but what if you painted the copper black? I did find someone using this technique, but their approach was to vapourize just the black paint, leaving the PCB traces behind as a resist for etching. Can't a laser cut through a thin layer of copper or are there safety concerns? -
If you have a 3D filament printer, why not print the PCB as just a single layer or two of plastic, etch, then remove the plastic. With a CNC mill, you could remove it just over the pads.
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So I hate protoboard. The only time I will use protoboard is when there are only a handful of components. Say a power distribution board in a multi-module lash up. Once you start with dozens of components and traces, its just too time comsuming and fiddly and using the green plated through hole versions, it's next to impossible to fix mistakes or get components back.
I do like PCBs. I just don't like the long (2-3week) lead time, the cost (when you include shipping to get it inside of 6-12 weeks). For me this tends to make me iterate and tweak and try and perfect each PCB I send for manufacturing. This elongates the process.
So I'm again looking at what options exist for an interim PCB made at home.
I did a little you tube watching last night and arrived at a few ideas.
1. Laser print positive onto paper. Heat transfer toner to a blank. Etch with copper chloride or whichever is easiest to order without a chemists account.
2. PCB resist print with 3D printer... etch as above.
3. Similar to above but with negatives and UV setting pre-resist coated blanks.
4. CNC approach using the 3D printer and a milling head + end mill.
On my travels I found something pretty cool. Creality make a 5W laser head for my printer. That will cut 3mm ply pretty easily. I'm going to imagine it reflects off shiny copper, so dangerous, but what if you painted the copper black? I did find someone using this technique, but their approach was to vapourize just the black paint, leaving the PCB traces behind as a resist for etching. Can't a laser cut through a thin layer of copper or are there safety concerns?
Where are you buying from? I use JLCPCB and get my boards back within a week for peanuts. -
Where are you buying from? I use JLCPCB and get my boards back within a week for peanuts.
PCBWay. They print the board within 48 hours usually, but it takes a week to get here at least. For 5 small dual layer it's only $5. But DHL or TNT shipping is $35. -
Hi paulca,
As other members underscored, dealing with a PCB manufacturer is by far the easiest solution.
But if you really want to manufacture vanilla PCBs at home, you may consider using a 3 axis milling machine (about 1000 bucks) and perform isolation milling. Seems to be a fair gear : one can see the linear bearings.
Much cheaper gear because of use of unsupported rectified shafts as guideways.
Those are really prone to buckling, so it's OK for PCB, but you won't be able to machine anything else.
You will also need to replace the crap spindle with a better stuff.
And don't forget that Tungsten-carbide drills instaneously break when used in a shaky milling machine. Any axis play is deadly. -
If you have a 3D filament printer, why not print the PCB as just a single layer or two of plastic, etch, then remove the plastic.
Because it will not hold sufficiently and resolution won't be good enough for SMT. -
Where are you buying from? I use JLCPCB and get my boards back within a week for peanuts.
PCBWay. They print the board within 48 hours usually, but it takes a week to get here at least. For 5 small dual layer it's only $5. But DHL or TNT shipping is $35.
Horses for courses I guess, but to me $40 and a week is a way better deal than fucking around etching or milling boards (I've done a fair bit of both, including toner transfer/UV/hand drawn methods). In my head I used to have this idea that DIY board making was "instant" and I could somehow still convince myself that was true 3 hours into the process. It works in an emergency where you absolutely need something simple the same day, but otherwise I can't justify it anymore when I really think about the time it takes to prep/etch/drill/etc. Plus there's chemical prep/cleanup/storage and the time it takes for all that.
Even doing it mostly automated on my CNC machine is a bit of a chore when you consider all the factors required to get good results (from physical mounting/z compensation for proper flatness across the board, to tool changes, to milling time, to cleanup, to snapped tools and restarts when you were 90% of the way through a board... etc)
The laser option might be a quicker/simpler process (no idea, I haven't used one yet) so could be worth investigating, but I feel like the other methods sound way more convenient than they really are in practice when boards are so cheap these days -
Resin printers can be used to expose photoresist on PCB with very good results. Laser engraver can be used to burn away photoresist or other protective coating.
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If money is not an issue, LKPF sells a nice UV laser + electroplating system for 4 layers in-house through-hole PCB manufacturing.
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1. Laser print positive onto paper. Heat transfer toner to a blank. Etch with copper chloride or whichever is easiest to order without a chemists account.
2. PCB resist print with 3D printer... etch as above.
3. Similar to above but with negatives and UV setting pre-resist coated blanks.
4. CNC approach using the 3D printer and a milling head + end mill.
On my travels I found something pretty cool. Creality make a 5W laser head for my printer. That will cut 3mm ply pretty easily. I'm going to imagine it reflects off shiny copper, so dangerous, but what if you painted the copper black? I did find someone using this technique, but their approach was to vapourize just the black paint, leaving the PCB traces behind as a resist for etching. Can't a laser cut through a thin layer of copper or are there safety concerns?
I have tried most of the methods you mention and find that each has problems greater than the time or expense of a PCB service.
1. Laser print on to paper. Actually fairly useful for low density single sided boards. But aligning a two sided board is hard and nearly impossible in cases that demand a two sided board (ones with small feature sizes that require side to side alignment). You will find the heat transfer process finicky so unless you keep the supplies and do the operation in a climate controlled area you will have lots of tries to get it right.
2. I haven't tried printing the resist directly on PCB, but do do a lot of 3D printing. I suspect that getting the filament to adhere to the board will require a lot of tweaking, and you won't be able to use any of the aids that the 3D printing community has developed as glue stick, hairspray and the like will be excellent resists in their own right. And the resolution is actually quite limited compared to surface mounted component requirements. Alignment of two sided boards will also be difficult though I can see some approaches that might work. The good news is that once the problems are worked out this would be one of the fastest approaches.
3. Blanks are getting harder to get as the commercial prototype houses have really reduced the market for these. And exposing the things turns out to be trickier than it appears. Be prepared for a significant learning curve.
4. I have a PCB mill. It works. But isn't as wonderful as some portray. There are many burrs on the edges of the removed material which if not removed interfere with reflow soldering. Best available resolution is not fantastic, and is only achieved with careful tweaking of tool height and perfectly flat and perfectly mounted PCB blanks. The one really great thing about the PCB mill is drilling any through holes that are needed. Obviously this advantage is declining as through hole technology fades into the past.
Another general comment about any of these methods when used in a mode that requires some precision (double sided, PCB mill, negative mask with sensitized board). Achieving the precision required usually requires tooling or holders. But unless you dedicate an entire blank to each board you create you will be dealing with odd size remnants as you cut (often by hand) your boards from the original blanks.
The laser head from Creality is likely to disappoint you. I don't know if they mentioned cutting speed in their material, but based on my experience with my 100W laser cutter, 3mm ply cutting speeds will be in the range of a few mm/sec. I haven't tried cutting comparable PWB fiberglass, but would guess that it cuts very significantly slower. I don't know the wavelength of the creality laser, but the CO2 laser in mine will effectively not cut metal at all. On most metals it will not even leave a mark. By coating the metal with appropriate materials you can make a mark, but it is more of a fusion with the surface than material removal. Some wavelengths will interact better, but generally kW of laser power are required for cutting applications.
The laser might make an interesting way to fuse a resist material on the PWB, but this would be research and invention. I don't know of any materials marketed for this purposed.
All this is a long winded way to say - despite their flaws, the commercial prototype houses are probably the way to go.
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I have a PCB mill. It works. But isn't as wonderful as some portray. There are many burrs on the edges of the removed material which if not removed interfere with reflow soldering.
Spread some thin oil (3in1 is OK) over the PCB to lubricate the bit, then you don't get burrs. As a bonus the tool lasts much longer too. Easily cleaned off with IPA. Takes care of the milling debris too, so vacuum extraction isn't needed (or wanted, come to that).Quotecareful tweaking of tool height and perfectly flat and perfectly mounted PCB blanks
Flycut the bed to make it flat (I use a half-inch thick perspex sheet as sacrificial bed) and then stick the PCB blank down with carpet tape. Carpet tape is very sticky, very thin, and pretty much consistent thickness, so it holds the entire PCB dead flat. Use a touch-detect circuit to set zero when you change tool (helps if your mill will automatically use it, but manual setting is the work of seconds) and small SMT shouldn't be a problem. -
I've used toner transfer extensively for prototypes - its quick and reliable once you get the process dialled in. For this you need a decent laser printer, proper toner transfer paper (I use Press'n'Peel Blue), and a temperature controlled hot-plate (forget about using a clothes iron). Doubled sided alignment is actually very easy - just put two moiré alignment coupons outside the board area (just sets of concentric circles).
So, some investment required, but I got to the point where I could reliably make a 2 sided board with 10mil traces in about 30 minutes. Best result was double-sided Kapton flexible pcb with 5 mil track/space - 23 out of a panel of 24 worked.
I've also tried a 50W CO2 laser cutter, using it to remove paint based resist from the laminate. It works, but takes a few tries to find the right paint (clear works best) and the right power. You can forget trying to laser off the copper - its too reflective and too thermally conductive. It would take very high power levels to do that, most likely from a q-switched NdYAG laser or similar. -
You haven't said what sort of PCBs you are making. Anything with vias on a DIY PCB is a huge pain in the ass.
See if you can find something to help with iterating, does printing it out help? 3D modeling the board and placing it in an example enclosure? etc.
https://www.eevblog.com/forum/eda/making-high-quality-home-etching-easy-66mil-pcbs-exposed-with-an-sla-printer/
https://www.eevblog.com/forum/beginners/what-is-the-best-way-to-make-printed-circuit-boards-at-home/
https://www.eevblog.com/forum/3d-printing/printing-pcb-with-3d-printer/ -
If money is not an issue, LKPF sells a nice UV laser + electroplating system for 4 layers in-house through-hole PCB manufacturing.
How many kidneys does it cost? -
Laser printer toner transfer using Press n Peel film is the way to go, it's how I've been making PCBs at home for years. I rarely do it anymore though since JLCPCB is so ridiculously cheap, but it's a nice option to have when I'm in a hurry.
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... its quick and reliable once you get the process dialled in.
You write there about etching, but I think that bit applies to any DIY method. Certainly, it took me some time and a lot of failures to get my etching prcocess working properly, just in time for the hassle of chemicals and tedium of drilling many holes off-center to encourage me to find a better way. That turned out to be CNC, but I already had a mill (not suited to PCBS, but it's a start) and even then it took a lot of failures and broken bits to get to the stage now where everything works well.
I think the only way to not go through the dialling-in thing is to farm it out to a PCB shop, but the downside with that is not finding the deliberate mistake until the board is in production and 5 days away from being delivered. At least with a homer you can fix it and restart without much of a problem (and no-one else knowing). -
I agree with PlainName, any of these processes requires a dialing in period. And for me, since I only occasionally decide to do my own boards, the dialing in process is repeated each board. Apparently I am not capturing the right stuff in my notes.
So these things probably work well for those who do it weekly, less well for the monthly board makers, and not so much for the annual ones. -
Frankly, these days I would only etch my own board if I needed one urgently. Which I have, from time to time (doing test runs of high speed discrete amplifiers). Otherwise a fab house really is the better way to go, considering how cheap it is. Well, anything under 100mm x 100mm is cheap. Go over that and it gets considerably more expensive, and the calculus changes.
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That's absolutely correct. Unfortunately, metal cutting or etchning with a laser needs a lot of power and the required laser source is not sold by Creality.
The laser head from Creality is likely to disappoint you. I don't know if they mentioned cutting speed in their material, but based on my experience with my 100W laser cutter, 3mm ply cutting speeds will be in the range of a few mm/sec. I haven't tried cutting comparable PWB fiberglass, but would guess that it cuts very significantly slower. I don't know the wavelength of the creality laser, but the CO2 laser in mine will effectively not cut metal at all. On most metals it will not even leave a mark. By coating the metal with appropriate materials you can make a mark, but it is more of a fusion with the surface than material removal. Some wavelengths will interact better, but generally kW of laser power are required for cutting applications.
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And when we talk about power, this means optical power, not electrical power, as usually indicated on Aliexpress.
Furthermore, the optical power is actually a peak power when speaking about a pulsed laser source, or a CW power if the lasers' output is a...CW.
The metal cutting domain for CO2 lasers usually begins at 400W optical power, (which means at least 4-5 kW electrical input power). But the fun only begins at 2 kW CW. You will also need 2500 l/h of process gas (Ar, N2, O2).
For high speed sheet metal cutting (0,8 mm steel), 6 kW CW optical power is standard. If you build an oil tanker with 10 cm thick steel, 20kW CW is definitely required.
CO2 best works for iron/steel and also, with limited performance, for aluminium.
Pure copper or matter that contains copper is almost not machinable with a CO2 laser.
A good alternative for high power (> 1 kW) CO2 laser are Ytterbium (and other rare matters) doped fiber lasers. They are rather cheap, really handy, and have very good efficiency.
For YIG lasers or even NIR diode lasers, lower power values can be sufficient for metal cutting, but I doubt that anything is seriously doable below 250W for iron/steel/aluminium. For copper, significantly more power is required.
LKPF uses green laser sources (12W, 8W) and also a 355nm UVA laser (5,7 W) in their Protolaser series. But, as a 'pulse frequency' is indicated, these power values are likely average electrical values. The laser source is probably Q-switched, which leads to optical power values in the kW range. And that's probably the ballpark value required for pure copper etching, even at these relatively short wavelengths, down to UVA.
As a comparision, sheet copper soldering requises a 1kW CW green laser.
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The demos I was watching on YouTube where the guy had a 2W laser mounted to his 3D printer.
He was able to cut 3mm plywood. It's just it took 16 passes. Apparently less passes at a slow speed resulted in much more charing. I think he was doing 16mm per second. 16 passes to get burn through.
If you are running a production operation that's too slow, a commercial laser cutter would do that in a single pass in 20 seconds. Not take 5-10 minutes. But if you are printing a box or a front panel for a project, who cares? right?
I'm just annoyed it probably won't do clear acrylic without a specialist laser
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The demos I was watching on YouTube where the guy had a 2W laser mounted to his 3D printer.
He was able to cut 3mm plywood. It's just it took 16 passes. Apparently less passes at a slow speed resulted in much more charing. I think he was doing 16mm per second. 16 passes to get burn through.
If you are running a production operation that's too slow, a commercial laser cutter would do that in a single pass in 20 seconds. Not take 5-10 minutes. But if you are printing a box or a front panel for a project, who cares? right?
I'm just annoyed it probably won't do clear acrylic without a specialist laser
YMMV. I find that cutting parameters vary with temperature, relative humidity, moisture content in the wood and probably several other factors I haven't identified yet. One bummer is that if you don't have it right it is somewhere between very difficult and impossible to go back for more passes. You have to move the piece to find out whether it cut through or not, and if you try to rework it must be aligned to within a fraction of the tiny laser line width.
I am sure you will be able to get it to work, but be prepared for several of those ten minute iterations to get everything the way you want it. And the results are definitely very nice.
I am assuming that the reason it won't cut clear acrylic is that the wavelength of the laser involved is not absorbed by the acrylic. There is some small chance that it will work for colored acrylics that might also be of use to you. If the dye used doesn't bleach under high intensity light and if you are content with large numbers of passes it has some chance of working. -
This is a useful website unfortunately only in german.
But google does the job.
https://www-mikrocontroller-net.translate.goog/articles/Platinenherstellung_mit_der_Photo-Positiv-Methode?_x_tr_sl=de&_x_tr_tl=en&_x_tr_hl=de&_x_tr_pto=wapp -
I still prefer CNC milling PCBs you can also drill the vias. The PCBs I made in the past were absolutely reliable, no over-etching and good surface. But the PCBs still need to be coated otherwise they'll corrode relatively quick and look ugly.
Warping of the PCBs can easily be handled via software.