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View Full Version : Curious: PCB etching - use printed traces as resist



DrStein99
01-06-2017, 02:56 AM
Can I put a bare copper PCB on the plate of the 3d printer, and print a layer of plastic (pla, abs, or WHATEVER is used) directly to a bare copper board? I want to print a printed circuit board pattern, and etch-resist the board after print. If this is NOT possible, can I know why / what happens?

Little_Chips
01-06-2017, 04:51 AM
It will be far greater end result if you use more conventional methods. Do a little searching on using laser jet prints and transferring them to copper board. Then etch. Note the copper has to be very clean. use a scotch bright then clean with denatured alcohol prior to transferring the mask. If your board isn't too big Eagle will allow you to generate a circuit and layout for printing. I believe you will have poor quality of traces if you pursue 3D print a mask. It may work with traces that are .125" wide but why use a clumsy method when the procedure/process for making boards is perfected even for hobbyist use. There are also several quality board houses for boards under about 6 square inches where you can get 3 perfect boards for $30 - $50 and they use the files generated by Eagle. You can also use CAD and generate a dxf file to print as a mask. The method you propose is the wrong direction to go imo. I am an electronic technician since 1980 and have successfully built many high quality boards. Good luck to you.

DrStein99
01-06-2017, 06:00 AM
I'm familiar with the toner transfer a sending away for pcb production. No thanks.

dharmic
01-06-2017, 07:37 PM
Two problems immediately spring to mind:

1. Accuracy. You have decent positional control with a printer, mebbe down to about 0.08mm / 3mil for placing the centreline of a track. But their width is much harder to get accurate so, for small stuff, you're going to have problems of shorts or breaks in tracks where it didn't quite get it right.

2. Adhesion. Getting your plastic to actually stick to that layer of copper is going to be a challenge.

Solving these two issues is going to be an order of magnitude more painful than toner transfer or photoresist exposure methods. Even then: I have a full photoresist exposure box with vacuum pulldown, bubble tanks, developing trays and chems I bought 20 years ago for prototyping and haven't used in years - it just doesn't make sense to do them here any more. Between the complexity and small scale of the boards I do to fit the modern SMD components, the value of my time, and the wish to be productive instead of dicking around with etchant etc, there's just no way to me that not sending it to a cheap mob like OSH Park or SEEED makes sense.

:edit: if you have to pursue this path to quiet some inner demon, perhaps consider printing a new head for your 3d printer which can hold a spring loaded Dalo (or other resistant ink) pen. Get it to just draw the resist down nice and accurately for you.

DrStein99
01-07-2017, 07:26 AM
Ok so your saying the hot plastic glue is sloppy, and I would end up having a nice adventure playing with the extrusion head. Ok, well I can understand that. There are so many of these tiny machines made out of sloppy leadscrews a shakey frames.

A_Camera
01-08-2017, 03:26 AM
Convert the printer into a CNC or build one. 3D printing PCB tracks is not going to work.

DrStein99
01-08-2017, 11:08 PM
I am interested in knowing how any why you believe print PCB tracks will not work.

A_Camera
07-13-2017, 09:15 AM
I am interested in knowing how any why you believe print PCB tracks will not work.

So, did you try it out?

Sorry for the late answer...

...maybe it would work, I am not an expert in 3D printing and how well the plastic sticks to the copper layer, but to be able to etch nice tracks the plastic must have nice and clean and very even edges, otherwise it will not look well enough. After etching you need to use other chemicals to remove the 3D printed tracks, so it involves a lot of wet handling. I am "etching" using my CNC mill and that works fine. No aggressive chemicals, dry process and very fast.

CNCMAN172
07-13-2017, 11:05 AM
Well it might be possible to get something like that to work, you might want to look on youtube at Lasers doing PCB etching. They can actually do this pretty fast with high accuracy. There are a couple of methods with lasers, one is to turn off all the area to etched away with chemicals, the second is using strong lasers that burn away all the copper not part of the design. Those are pretty amazing but my guess is those lasers are probably costly.

Russ

justCNCit
09-29-2017, 10:24 PM
You can try use DLP 3D printer to do this which is much more accurate I was going to do it till I burned out the projector.

gcz
09-30-2017, 07:02 PM
well, you can print wax and it will stick but you will have difficulty controlling trace width cuz big nozzles.
you can coat your pcb with black paint and laser that with a diode laser, too- that will get you very acceptable accuracy and control over feature dimensions.

justCNCit
03-07-2018, 09:03 AM
update if you have tried this. A friend of mine is an electronics guru and we had been working on this and it has been mentioned on the net but no one has followed through. We can't think of a reason it wouldn't work but has to be tried