Laser build questions CNC IR Pyrography

Hi, this forum is great, filled with experience. Exactly what I don't have right now. I'm looking to build/buy a laser for under 150 that I can use for wood burning designs in a homebuilt CNC setup. FYI, I'm decent with electronics, but I don't have any machining tools. I'm not really a laser hobbyist, though I did make a little red laser spirograph a few years ago w/ pwm and speed control that runs off of a micro.

I've already figured that a 1w 808 would probably be the best bang for my buck (let me know if you disagree), but what I have the most questions about are focal length and cooling. I expect to run this thing for several hours a day maybe in high ambient temps, and I want to make sure cooling is not an issue. What would you guys do in this scenario?

Also, I would like to be able to setup an optimal point at a long focal length, say 1.5 - 2'. Will any adjustable lens setup allow me to do that?

I am far from an expert on CO2 lasers. I believe most use a fixed head and a traveling "arm" with mirrors in it to position the beam. Also , I do not think 1W will be enough power. From what I've read, around 10W is the starting point.
Here's a site with a little more info.
Laser Cutting Machines
Also, a lot of good info here.
Sam's Laser FAQ - Carbon Dioxide Lasers
Good Luck!

Greenmechanic said:

I am far from an expert on CO2 lasers. I believe most use a fixed head and a traveling "arm" with mirrors in it to position the beam. Also , I do not think 1W will be enough power. From what I've read, around 10W is the starting point.
Here's a site with a little more info.
Laser Cutting Machines
Also, a lot of good info here.
Sam's Laser FAQ - Carbon Dioxide Lasers
Good Luck!

Click to expand...

Hey, thanks for the response. I probably should've been a bit more specific in my specs. I don't really need to do anything other than be able to make dark fine lines on wood. It looks like this is quite doable with a 1w. I don't know much about C02 setups, I'll have to research them.

See, my idea is to be able to burn designs on wooden coins at fairs and events and such. So, whatever I end up with needs to be portable, not too finicky, and be able to run off of a couple of car batteries all day.

Then you can probably use an 1W or 2W fiber coupled laser ..... the fiber permit you to mount the laser on an heavy heatsink outside the CNC moving part (if the course is small enough, otherwise you still can moutnt the laser and heatsink on one of the moving parts, and drive the fiber to the final moving head) ..... also, the fiber permit you to collimate the beam in a better point, instead a "line" like most of the IR diodes .....

Something like this one, or something similar, can be a good solution, just as example ..... this is an 835nm one, so can be a problem to see the collimated spot, if not using a camera with a ND filter ..... but time by time there are 808nm or 780nm units, similar to this one, for sale, and in these cases, the collimated spot is still visible in faint red, so you don't need to add a red guide beam or a camera (but ALWAYS use protective goggles for IR) .....

That looks quite good. I'm not terribly knowledgable about lasers. Columnated means the photons are moving in all directions, right? Will I benefit at all by focusing it after that, or do those units have pretty tight enough beams for burning wood? Also, if you know, do you have any idea how fast burning a line might be? 1 in per sec, 1/2 in per sec on a maybe ligher colored wood?

Oh, yes... I will wear goggles, and be very very carefull.

Collimate definition. For this project you do not want to collimate the beam, you want to focus it.

1W is enough to burn wood, but it won't move terribly fast. Focusing can be done with a regular convex lens.

What I would do: get a 1W laser diode from ebay, and put it in a blank Aixiz module within some sort of heat sink. You then only have to provide a regulated ~2V ~1.2A to the diode. I'm sure other members will chime in with more details.

Thanks. I pulled the trigger buying a diode last night, don't know if it was the best choice, but we'll see how it turns out. At a late hour, and bleary eyed from researching, I eliminated the CO2 laser option, went to E-bay and bought a 3w 808 with TEC, mounting, and optics for DPSS for $70 free shipping. I wasn't thinking very straight last night. So when I woke up, I checked the seller's rep (seems okay), and noticed the lack of specs on everything. Hope it all turns out okay.

I'm now digging around to get schematics for a switch mode driver for this.

do you have any conclusions by now. I am interested in the purpose you bought a diode for but i haven't worked out a driver for it yet. I am really interested in the cnc and pyrography part of it.