New member seeking advice for 2 different laser projects

Hello folks, new to the LPF and lasers >"5"mW.

As the title says I am looking to use 2 different lasers for 2 different purposes but I'm unable to find some info and I'd also Like to discuss some technical information to see if one of the projects is even feasible with a hobby level budget.

The 1st and easiest project (not really even a project) is I'd like to get a burning laser preferably in the visible light spectrum 405-680nm range that can pop balloons and more importantly light fireworks, yes I realize a lighter, matches, or other source of fire is easier slightly safer and definitely cheaper but I'd rather just be able to press a button and light the fuse, and still be able to do a balloon shoot out at the ok coral, then just recharge some batteries to be able to use it again later. The thing is I'm not looking to be like OMG YAY I haz 1W lazor that cans light fuses and go pew pew, I'd like the minimum wattage that could do these tasks, pop a balloon from say 5-10ft and light a fuses from a few inches to say a ft or so away and cost maybe $50-100 (would prefer the lower price range though).

Also for either one of these I'd buy the appropriate safety glasses since it's the safe thing to do and you folks can't seem to advocate it enough.

The second project is the tough one that has the most ambition and most practicality and that I like to make a cnc engraver / etcher that would primarily be used to make pcb's but also be usable on most plastics, such as ABS, plexiglass of any color and opaque-ness while being able to do the process within say a 5 hour window (just so it doesn't take forever and because anything that would be lightning fast would cost several thousand dollars).

As for the cnc laser engraving actual laser I understand a lot of the "ability" to cut/engrave/etch depends on what wavelength the material in question can absorb, and from a little bit of the information on this article http://www.laser-systems.net/pdf/Copper welding4.pdf about copper welding where they demonstrate using a pulsed Nd Yag laser and how it either results in power ablation of the copper or completely obliterates it vs using a "green" or 532nm pulsed Nd YAG laser and how it has better results due to better absorption on the lasers energy. Now sure I realize that in the article they are discussing the use of a Yag laser and the fact that it's somewhere in the 1.5Kw range (which is way outside they price range for a hobbyist) but I presume they are referring to using this in a single quick pass for rapid developement versus, say a 1+ hour multi pass process that is aimed at removing a little bit of the copper at a time, also what makes me think that a green or possibly even down to say a 405nm laser at say the 500mW-3W rane might work was this video I saw of a professional pcb CNC laser posted on the cnc forums

if you look at the close up at 45 seconds in it looks like it's a green laser, but a better close up at approx. 1:00 in seems to back this idea up, however 2 things could be argued 1 being that the laser in question is most likely 10's if not 100's of watts versus the power I'm talking about but I'm also talking a bout a slightly slower process, and the 2nd point is that the beam may actually be of lower wavelength due to the fact that copper burns green.

So I pose the questions of, if a 500mw-3W 405-532nm laser is used and focused down to say 5mil or so (apprx. .127mm) could the power density be enough with several passes to oblate copper to be able to make pcb's without the use of chemicals, as well as if anyone has tried using a 532nm or lower laser at these power levels with multiple passes to etch/engrave/ or even cut copper with enough passes?

Sorry for the very long 1st post and thank you for any suggestions / discussions/ or advice.

P.S. There are links in there but I couldn't figure out how to make them more visible.

On number one, your looking at about $150 minimum for a decent 'burning' laser that fits your criteria.

And number two.. a CO2 laser will be your best bet, especially for the transparent materials.. since wavelengths in or around the visible range will pass right through them.

Thanks for the input Qumefox, for the CNC Idea though I'm mostly aiming for pcb etching without chemicals, the idea of doing plastics is so the project would be more multifunctional vs uni-functional, a CO2 laser probably isn't going work for the copper aspect since CO2 wavelength is 10.6um I believe and I'm pretty sure that the copper would reflect a good deal of the energy possibly destroying the laser or surrounding items.

Also I hate to sound like rude but are you sure that using a visible light laser would just pass through clear plastics or would it do some "damage" just not enough or the type of "damage" I'm looking for?

For the 1st burning laser I was asking about would you or some else mind giving a suggestion as to what wattage and wavelength I'd be looking for, so I could keep an eye out for a good deal on a laser?

Um.. There are very few things that reflect 10600. Gold is one of them I know. 99.999% of things absorb that wavelength. Which is why it's used for cutting and engraving. The problem your going to have with that is that anything that will cut the copper will cut through the fiber layers a LOT faster.. Commercial boards are still chemically etched for a reason. That's the best way to do it.

For a burning laser you want either a 405 or a 445. 445 is capable of more power, up to 2W or so, but 405 will give better 'distance burning' due to it's better beam characteristics.

qumefox said:

On number one, your looking at about $150 minimum for a decent 'burning' laser that fits your criteria.

And number two.. a CO2 laser will be your best bet, especially for the transparent materials.. since wavelengths in or around the visible range will pass right through them.

Click to expand...

agreed

agreed^^^^

also, yes, visible wavelengths pass through clear plastic and it is inherently dangerous because of reflections.



michael.

Ah tahnk you again Qumefox for the information and clearing up my misunderstanding about CO2 Lasers and the 10600 wavelength.