Laser Etching PCBs

[sturgeo]

I want to have a go at etching a few PCBs, I've never done it before & me being me, probably want to make it more difficult for myself using the equipment I have.

If I were to spray paint a sheet of FR4 and laser engrave the etch artwork (I'll need to invert this so it removes the correct material) that should work right? I might need to try a few different types of paint to see what works best, and then obviously proceed with the normal etching method.

Has anyone with a laser attempted this?

[komigenie]

I did, and come out awesome, now - my advice is to use High Temperature grill paint or paint will turn to some kind of messy sticky layer ....

http://www.homedepot.com/p/Rust-Oleum-Specialty-12-oz-Bar-B-Que-Black-Satin-High-Heat-Spray-Paint-7778830/202315061

[culturejam]

Wow. I would have never thought of that.

[selfdestroyer]

Thats some great detail on that etch komigenie.

Cody

[sturgeo]

Ooo impressive, glad I'm not barking up the wrong tree for once

Time to buy some chemicals and tell the mrs i'm getting my Heisenberg on in the garage!

[m-Kresol]

before you buy anything wrong, I have to say that FeCl3 is working very well for pcbs (and enclosures). Stay away from any mixtures of hydrochloric (muriatic) acid with hydrogen peroxide or even worse sulfuric acid with peroxide. I've seen both around here and both are (especially the last one is ridiculously oxidizing and corrosive) quite dangerous. More dangerous than necessary for pcb etching at least.

now I can sleep with good consciousness.

[sturgeo]

Thanks for the heads up, fortunately I'm limited for choice for products like this and Ferric Chloride is one of the only products available off the shelf. For the rest of the process i'll use selfdestroyer's excellent tutorials, might attempt a reverse etch on some old enclosures once I've got enough used etchant 

[sturgeo]

Well, i had a pop at this over the weekend and wasn't very successful.

I sprayed the FR4, let it dry, lasered away all the paint to be etched, popped it in the etchent(Ferric Chloride - MG Chems 415) and nothing... it would appear that enough residue was left behind to stop the process, next time i'll try 2 passes with the laser, it looked as if all the paint had been removed. I probably left it in the etchent for 45mins in the end. I then struggled to remove the paint that was left by hand, probably need to etch it and then run it under the laser to expose all the copper for soldering.

I then tried the usual toner transfer method for the first time, possibly a little too over enthusiastic as i tried to do a 150mm x 100mm board with 16 small pcbs on all at once, after a long soak some have transferred ok, i think i'll wirewool the lot and split it up into smaller pieces, rough it up with some 600-800 grit and try again.

I'm hoping i can get the laser method dialled in as its a lot easier & quicker!

[galaxiex]

Not to hi-jack the thread, but does anyone here have experience with those cheap laser engravers I see from China/Hong Kong on ebay?

Some are less than a hunnert bucks!
Any good?
Any recommendations for a inexpensive laser engraver?

Thanks!

[culturejam]

Not to hi-jack the thread, but does anyone here have experience with those cheap laser engravers I see from China/Hong Kong on ebay?

If you want to lightly mark very small pieces of wood or paper, they are ideal. For anything beyond that, they are somewhat useless.

[komigenie]

Well, i had a pop at this over the weekend and wasn't very successful.

I sprayed the FR4, let it dry, lasered away all the paint to be etched, popped it in the etchent(Ferric Chloride - MG Chems 415) and nothing... it would appear that enough residue was left behind to stop the process, next time i'll try 2 passes with the laser, it looked as if all the paint had been removed. I probably left it in the etchent for 45mins in the end. I then struggled to remove the paint that was left by hand, probably need to etch it and then run it under the laser to expose all the copper for soldering.

I then tried the usual toner transfer method for the first time, possibly a little too over enthusiastic as i tried to do a 150mm x 100mm board with 16 small pcbs on all at once, after a long soak some have transferred ok, i think i'll wirewool the lot and split it up into smaller pieces, rough it up with some 600-800 grit and try again.

I'm hoping i can get the laser method dialled in as its a lot easier & quicker!

Well, i was using 40 watts laser, and removed paint with 2 passes what removed paint - but leave some thin "dust like" layer what i clean with Magic Eraser and then etch ... You can see results on photo i posted ! Was i clean and fast process !

[sturgeo]

Thank you Komigenie, i gave it 3 passes with the laser to be sure, successfully etched and then scrubbed the unnecessary paint off with some wire wool.

Also thanks to Cody for the excellent tutorials