Acme Thread, Ball Screw Or Belt Drive for Laser Cutter/Engraver?

[pyrofx]

I'm designing a laser cutter/engraver. My expertise is in electronics not mechanical engineering but I have seen several homebuilt designs using each of the methods to drive the system. Already have the laser(s) sorted out with a 15w CO2 and a 75w ND:YAG but burning stuff indiscriminately is only fun for so long!

Most laser cutters seem to use a belt drive pulley system but this seems to me to require higher torque steppers and have a fixed resolution related to the steppers resolution. The gantry carrying a mirror is certainly much less weight to slew around than a router. However, I would like to build a system that may have the top gantry mount replaced with some additional components to do routing as well.

Wouldn't a leadscrew system be more capable of doing both. Also your steppers would have increased resolution depending on the TPI you pick for your leadscrews? Depending on the TPI you could trade off speed for resolution. Maybe even different rates for each axis?

Any advice from those who have built their own systems is welcomed.

[Konstantin]

Hi. I find the diolde lasers fascinating. Could you post some pictures of the YAG laser? Tell us more details, like where did you purchase the laser, how did you assembled it.

I suppose you wish to make a router/laser with the ND YAG, is that correct?

Right now I am building my X axis, I think going with belts, I like the Servbelt system, dont know if I am going to use their design.

[pyrofx]

The CO2 laser is a Directed Energy RF head at 15w and the ND:YAG at 75-85w is the guts out of a medical laser.

I can post some pics if I fire them up in the next few days.

[zax15uk]

The best option for a laser would be small stepper or servo motors with a belt drive, but as you say that isn't suited to a router.

I do not recommend trying to make a multi-purpose system. That's how I started out, retrofitting a laser to my home built router. They just have different needs and a combination isn't very effective.

A laser (for rastering/engraving) requires a low mass head for rapid movement, and having a routers Z-head (w/motor) and/or spindle on it won't allow the optimum speeds that a laser could achieve.

Routers are generally dusty, even with a good extraction system. Dust can quickly kill the optics on a laser system, so you'll be cleaning a lot!

Zax.

[pyrofx]

Thanks for the input, the more I have thought about it, the needs for router and lasers are too different. The gantry would be way different as you say due to mass. The only parts that would be reused is the table and rails. Those are the cheapest parts anyway, might as well build two system.

[kewlkiwi]

The only parts that would be reused is the table and rails.

How about using the table and rails for both?
e.g. on one end of the table, have your laser gantry, and the other end, the router.

When the router is in use, the mirror, lens, etc on it's gantry is simply moved as close as possible to it's 'end' (perhaps covered to keep the dust out of the optics) and when the laser is in use the router's gantry is moved right up to _it's_ end of the table.

Bob