Odrive for galvanometer


#1

Hi I am trying to build a galvanometer for a laser etcher project.

So it is 2 motors, controlling the tilt of 2 mirrors. Since its only 2 axis Odrive made sense.

Can any one tell what is the maximum precession in step we can achieve with Odrive?

Any suggestions on motor and encoder selection for the galvanometer?


#2

Allowing for a decent settling time, you can reach +/- 1 encoder count. So it mostly comes down to how high resolution your encoder is. The highest resolution encoders we know of that are affordable are multipole magnetic encoders, like the one presented at the very bottom of this post: Project HoverArm, and in this topic: Where to source magnetic encoder and ring?.

Since you are moving a tiny mass, I would recommend an inrunner motor, since their rotor moment of inertia is small. Something like this:

That said, why not just buy an off-the-shelf system like this one?


#3

Thanks for the post, after further study and XY belt controlled laser control for the etcher seem to be a better approach.

Lots of spares and lots of designs to work with.


#4

Oh, yeah. Laser cutters / etchers don’t work well if the distance / focal point changes. XY is a better option.


#5

Well there are flat field and F-Theta lenses, but they’re usually a bit expensive.

https://www.aliexpress.com/item/Galvo-Steering-Mirror-for-Fiber-Laser-Etching-Machine/32727187795.html


#6

I’m wondering for a long time if instead of F-theta lens you could do active focus - like the CD/DVD drives are using. Provided correct lens attached to the solenoid it should be possible to compute required parameters for this virtual Z axis depending on target X/Y position.


#7

That would be neat. I’ve been tempted to try a motorized focuser and attempting subsurface.