how do I laser?

[LaserLotus]

I want to mount a blue or uv laser to my hobby mill for burning power. The mill can move a workpiece in the x/y plane underneath the laser so the laser can be stationary and need focus on one point only (or the laser can be mounted to the spindle and fired from a calibrated height above the workpiece). I know next to nothing about lasers/optics so I am hoping to get some advice on what would make a good first build; i.e., nothing too expensive and nothing too complicated. Here's what I would like the system to be capable of:

- blue/violet output for higher power and easier focusing.

- PC toggleable. I use a gecko g540 to drive the mill and it has outputs that short to ground when toggled, so I think this should be able to turn a laser diode on and off by just wiring the diode's ground to the g540 output as long as the diode's DC source is connected to the ground of the g540 it should work.

- small spot size for precise roasting: ideally around 0.05mm (50 microns). distance from laser to workpiece preferable at least 5cm but I've heard that focusing is harder at longer distances.

So what kind of diode should I buy from where? Are there any low-cost diode/lens systems for sale that I could adapt rather than finnicking with the diode itself? What kind of lens is appropriate for this project and where would I buy one? From the sounds of it collimation is not necessary since my working distance does not change so I just need a converging lens? Can a collimating lens be used at a slightly different distance to produce the necessary focusing? Can any of the higher-power "laser pointers" be easily adapted to focus to a 50 micron spot?

Any advice appreciated.

 

[Eudaimonium]

Blue build with 445nm diodes are easy to build.

If you are looking for digital control over the laser, look into TTL drivers for that. Those are going to be a bit tougher to build, but you seem to know your way around electronics so it should not be a problem.

No idea about the tiniest spot achievable. You will just have to experiment with that and see.

Use a diode in an Aixiz module, and get glass lens for it - standard M9 glass lens, you can find it easily anywhere an Aixiz module is sold. That's ALL optics there is there in your project, you don't need to worry about anything else.

 

[Npglaserer]

I am not a hobby mill expert, but I will try to answer your questions.

Blue (445 or 450nm) will get you the highest power for the price.

Not sure about the PC toggleable part, but it should work.

I do not know if you can get that small with the dot, but maybe someone else knows.

As for the diode, I would recommend either the M-140 or the Osram PLTB450B from DTR.

The M-140 is multimode, which gives it a differently shaped dot, so you may want to get the single mode Osram.

Depending on what you need to do, you might want more power than the Osram, but it should be able to do a lot.

Links
M-140: https://sites.google.com/site/dtrlpf/home/diodes/445-m140-didoes
Osram: https://sites.google.com/site/dtrlpf/home/diodes/osram-pltb450-1-4w-450nm

I would get the driver installed unless you want to DIY.

Remember that you will need safety goggles if you are going to be in the same room as the laser. You can get those here: Eagle Pair® 190-540nm Standard Laser Safety Goggles

Good luck and welcome to the forum! I suggest that you make a thread in the welcome section to introduce yourself.

P.S. lasers get hot, so you will need a heat sink or active cooling to prevent overheating.