PCB engraver using lasers? - Page 1
Forum section: electronics / projects

author: IonizedGears
author_rank: Regular Contributor
timestamp: March 10, 2013, 04:15:48 pm
content: I was thinking about how my electronics school should get a pcb engraver then it hit me, why not make a pcb etcher with a laser? I'd say with the right controls and a automatic variable focus laser(possible right?) and adjustment on how much power it would take to go through just the copper and not the fiberglass it is definitely possible. Plus, think how great it would be: quick, no changing bits, if you have a very fine laser it would be possible to achieve very very high resolution. I'm talking about this both in wouldn't this be awesome kind of way and would it be possible to get one for my school kind of way.

author: mariush
author_rank: Super Contributor
timestamp: March 10, 2013, 04:38:44 pm
content: Copper is very hard to cut with laser, you need a very powerful one... in the realm of hundreds of watts. Copper absorbs heat very well and it's also very reflective, and that causes problems.Cheap Chinese laser engravers are usually 40-60 watts, really impossible to cut copper with these.

author: IonizedGears
author_rank: Regular Contributor
timestamp: March 10, 2013, 04:49:14 pm
content: What if you preheated the copper clad until medium heat saturation then used the laser to etch it? That way it you wouldn't need a very powerful laser?

author: mariush
author_rank: Super Contributor
timestamp: March 10, 2013, 05:00:51 pm
content: And what are you gonna do about reflectivity? Stuff that reflects light is very hard to cut with a laser...Seehttp://www.ctechlaser.com.au/lctheory.pdfSeehttp://physics.stackexchange.com/questions/2709/laser-cutting-drilling-of-copperAlso, seehttp://www.k3pgp.org/Notebook/Lasersam/laserco2.htmQuoteThe closest you may be able to come to would be cutting very thin mild stainless steel sheets, as this guy did with a 30-40w laser:http://hackaday.com/2013/01/22/laser-cut-pcbs/But even so, the optics were so lousy he couldn't even cut holes for a DIP chip in the metal, it's not precise enough.

author: Kremmen
author_rank: Super Contributor
timestamp: March 10, 2013, 05:04:21 pm
content: Not to mention avoiding walking the rest of your life with a white cane. A gizmo like that would qualify into the heaviest class of laser radiation with matching heavy safety requirements (at least here in the EU). I say forget it, it is asking for tears and frustration. Lasers like that are not harmless toys.

author: Marco
author_rank: Super Contributor
timestamp: March 10, 2013, 05:29:50 pm
content: Pulsed laser with ns range pulses would work ... and people have DIY'd cutters using pulse lasers.http://4hv.org/e107_plugins/forum/forum_viewtopic.php?146258.0#post_146266Not going to be fast, easy or cheap though.

author: djsb
author_rank: Super Contributor
timestamp: March 10, 2013, 05:32:39 pm
content: Do you mean something like this?http://www.lpkf.com/products/rapid-pcb-prototyping/laser-circuit-structuring/laser-micromaterial-processing.htmDavid.

author: IanB
author_rank: Super Contributor
timestamp: March 10, 2013, 05:40:03 pm
content: Even if you could get it to work I think a secondary problem is the laser would vaporize the copper and cause copper to be deposited where you didn't want it (i.e. between the tracks). Look up sputtering as a common method of metal deposition. I feel you would get a very similar sputtering effect with high power laser pulses.

author: Marco
author_rank: Super Contributor
timestamp: March 10, 2013, 05:47:41 pm
content: Quote from: IanB on March 10, 2013, 05:40:03 pmIf it was a problem even with a high flow air stream you could put a high voltage on the copper and near the lens to keep the debris away.

author: IonizedGears
author_rank: Regular Contributor
timestamp: March 10, 2013, 05:53:49 pm
content: Quote from: djsb on March 10, 2013, 05:32:39 pmYeah, that is what i mean but without all the prices etc. but eh might not be possible for the price

author: metalphreak
author_rank: Frequent Contributor
timestamp: March 12, 2013, 01:10:27 pm
content: IIRC, I've seen people do it by spray painting the copper side black (instead of toner), lasering off the PAINT, then etching as you normally would in a chemical bath.

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 12, 2013, 03:39:45 pm
content: Quote from: metalphreak on March 12, 2013, 01:10:27 pmThat's exactly how they manufactured PCBs at Texas A&M University. The copper etching was very precise, but the lack of solder mask means that SOIC is the smallest size supported and via plating wasn't very good.As for making PCBs without a chemical process, EDM might work well.

author: G7PSK
author_rank: Super Contributor
timestamp: March 12, 2013, 04:10:13 pm
content: When laser cutting copper or any other metal the main problem is reflective property of the metal it is normal practice with shiny metals to cover them with a black plastic film, stainless steel and aluminium are the worst offenders for reflecting the beam.