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...