Direct laser PCB etching (through Cu ablation)

[Benm]

I don't think it can happen that way, and the evaporated Cu should obviously not be inhaled. The ablation would be carefully controlled by the PWM'ed optical output, just as it's done in professional machines.

I meant that it would deposit on a cold piece of your circuit board, unless you have really good ventilation to remove it immedately (at which point it will probably deposit into a hose that sucks it away or something. Copper vapour would certainly condense, and fine copper particles may also stick to things.

Obviously you should never inhale those, i'm sure that it would be pretty hazardous.

 

[DiegoChajtur]

any news?
i want to buy 15w 450nm laser for pcb etch

 

[Encap]

any news?
i want to buy 15w 450nm laser for pcb etch

So buy one. lol

Avoid necroposting on dead threads--frowned on here---last post and interest here was 1 year ago

Consensus seems to be an ordinary laser diode won't cut it (literally). You need something like a Q-switched laser, pulsed at 10's of kHz. The peak power has to be extremely high to ablate copper (>2500°C), and some nasty fumes come off the epoxy substrate, which have to be exhausted. Even a 40W CO 2 CO2 CW laser won't cut thin metal foil- it just bounces off. See: https://electronics.stackexchange.com/questions/100857/laser-diode-to-remove-copper-layer-from-pcb

 

[Alaskan]

Sniff, likely HMT?

 

[Encap]

Sniff, likely HMT?

Probably troll yes
HMT maybe?? lol

 

[DiegoChajtur]

So buy one. lol

Avoid necroposting on dead threads--frowned on here---last post and interest here was 1 year ago

Consensus seems to be an ordinary laser diode won't cut it (literally). You need something like a Q-switched laser, pulsed at 10's of kHz. The peak power has to be extremely high to ablate copper (>2500°C), and some nasty fumes come off the epoxy substrate, which have to be exhausted. Even a 40W CO 2 CO2 CW laser won't cut thin metal foil- it just bounces off. See: https://electronics.stackexchange.com/questions/100857/laser-diode-to-remove-copper-layer-from-pcb

I had already read that,
At the beginning of this thread, it was asked that someone who had a powerful laser, try to remove copper from a pcb ...
I do not want to buy an expensive 15w laser, if that is not going to work for me ...

Thanks

(sorry for my English)

 

[Alaskan]

IDK, changing my view, I've searched the web for information which led to a forum I was completely unfamiliar with and posted a question in an old thread before. They didn't like my necro-posting, but I found the thread on a google search. Maybe legit question..

 

[Encap]

IDK, changing my view, I've searched the web for information which led to a forum I was completely unfamiliar with and posted a question in an old thread before. They didn't like my necro-posting, but I found the thread on a google search. Maybe legit question..

yes could be that.

He has an answer of a sort--will not work is the consensus---reflective metals, are difficult to laser cut using CO2 lasers include yellow metals such as gold, copper, brass and bronze.

"In this work various problems concerning cutting copper sheets using CO2 laser are reported. First, all copper thermophysical properties, that regulate the process dynamics, and then the weight of each parameter has been evaluated numerically, even though only approximately. The surface absorption value of copper at room temperature and near the melting point and the order of laser power that is necessary to cause a gradual raise of the workpiece temperature from room to melting have been estimated. Then, the order of the cutting speed at which a sheet of a known thickness can be cut has been calculated. The analysis of all these problems, and the process dynamics and state of the art seem to confirm the validity of the current thesis on the impossibility of cutting copper by CO2"
From: Cutting copper sheets using CO2lasers | SpringerLink

Another but more hopeful about copper:
"During a decade and a half of industrial applications with carbon dioxide lasers, many different materials- metallic and non metallic have been cut by C02 lasers. But the basic physics of laser beam absorption and subsequent thermal conductivity involved in the cutting process have made a few materials poor candidates for laser cutting. Copper, in particular, has long been thought uncuttable on a practical basis. We have successfully cut copper sheets ranging from 0.2 to 4.0 millimeters thick with a 2 kilowatt CO2 laser. The processing speeds can be significant : micro-graphic sections of the various work-pieces show that the laser cutting quality is quite good. This article consists of two basic sections-a brief review of the process dynamics of laser cutting and a discussion of our experimental results. For simplicity of expression we will refer only to metallic work-pieces in this discussion. "
From: https://www.researchgate.net/publication/236269958_G_Daurelio_-_Cutting_Copper_Sheets_by_CO2_Laser_Long_Thought_Uncuttable_on_a_Practical_Basis_Copper_Has_Surrendered_to_the_CO2_Laser

 

[paul1598419]

This is not a necropost, but I am putting it here because the webcast, by Laser Focus World, and sponsored by Ophir, II-VI Incorporated, Lasertel, and Eagleyard Photonics called "Understanding High-Power Laser Diodes" included a part about copper absorption at 450nm wavelength which reminded me of this thread.

https://event.webcasts.com/starthere.jsp?ei=1144018&tp_key=cc837ecda0

 

[Rivem]

I outlined why you would need either a q-switched or massive kilowatt scale laser to do this over a year ago in the initial few posts. A 15W 450nm laser would be hopeless for copper ablation.

 

[paul1598419]

Yeah, I saw that post, but I had to put this somewhere and the CW 450nm laser they were talking about for copper made this seem like the best place for the link to the webcast. It wasn't about that so much, but that did catch my attention and seemed like information someone looking to do this would find interesting.

 

[Rivem]

Yeah, I saw that post, but I had to put this somewhere and the CW 450nm laser they were talking about for copper made this seem like the best place for the link to the webcast. It wasn't about that so much, but that did catch my attention and seemed like information someone looking to do this would find interesting.

Yeah. No worries. Just wanted to make sure that the original necroposter got a clear message.

 

[Benm]

I'm not reallly sure what the point of it woud be.

Directly blasting off the copper probably is not the best of ideas, but you could use 405 nm lasers to illuminate the photoresist layer or normal pcbs and them develop and etch them as usual.

 

[SIEVA]

Hi Guys!

After having accidentally come across this YouTube video, I decided to look back in this old thread. Starting at 3:10, you will see someone (who are likely also a member of this forum) using a 7 * 7W = 49W collimated blue laser bank, to cut and melt a carpenters steel blade. Although Cu has a very different energy absorption, a PCB Cu layer is much thinner than that blade.

Thus my original idea stands yet unproven, since as far as I can tell, nobody have done much testing. Most of you here have access to a wide variety of high powered diode lasers, and I don't, so there is not much I can do except trying to convince someone who does have a couple of these, to put more effort into it.

Also I'd like to emphasize that I am not interested in any other laser technologies than diode lasers for this project. Of course we can find a cheapo CO2 one, but its totally OT for this project. PCB manufacturing by laser CNC ablation.

So what is the next step?

Grab a FR4 PCB and find or cut out a lonely Cu island. Roughen the surface a bit with sand paper. Heat it up to about 200C in oven or with blow torch.
Now bring out all your best HP LPs and focus on the spot. Anything? How about painting it black or adding a bit of silver solder?

Alternatively: Make a medium wide (~2 mm) and 2 cm length of Cu "canal" and pass a current through it, to heat it that way, while lasing it. We all know how easily we can burn off a wire...

We need something very well focused with around 10-50W to see anything, when using < 405 nm pulsed lasers.

PS. I couldn't see that other laser focus world webcast...

 

[diachi]

Hi Guys!

After having accidentally come across this YouTube video, I decided to look back in this old thread. Starting at 3:10, you will see someone (who are likely also a member of this forum) using a 7 * 7W = 49W collimated blue laser bank, to cut and melt a carpenters steel blade. Although Cu has a very different energy absorption, a PCB Cu layer is much thinner than that blade.

Thus my original idea stands yet unproven, since as far as I can tell, nobody have done much testing. Most of you here have access to a wide variety of high powered diode lasers, and I don't, so there is not much I can do except trying to convince someone who does have a couple of these, to put more effort into it.

Also I'd like to emphasize that I am not interested in any other laser technologies than diode lasers for this project. Of course we can find a cheapo CO2 one, but its totally OT for this project. PCB manufacturing by laser CNC ablation.

So what is the next step?

Grab a FR4 PCB and find or cut out a lonely Cu island. Roughen the surface a bit with sand paper. Heat it up to about 200C in oven or with blow torch.
Now bring out all your best HP LPs and focus on the spot. Anything? How about painting it black or adding a bit of silver solder?

Alternatively: Make a medium wide (~2 mm) and 2 cm length of Cu "canal" and pass a current through it, to heat it that way, while lasing it. We all know how easily we can burn off a wire...

We need something very well focused with around 10-50W to see anything, when using < 405 nm pulsed lasers.

PS. I couldn't see that other laser focus world webcast...

The problem with CW diode lasers is that you'll heat up (And potentially damage) the surrounding material too, not just the material you're trying to remove. I don't think anyone (on here at least) has enough power at ~405 or ~450 to test this.

That's the advantage of Q-switched lasers, the peak power is so high that the target material is ablated before there's time for heat to transfer to the surrounding material.