Friction roller type rotary

[Greg Holt]

I have a chuck type rotary axis for my home built RECI powered 60w laser. It works well.

But I am now going to build a friction roller type rotary for more versatility. (or just because I want to) :)

It will be stepper motor driven style, of similar principals to the pics below.

My question is, what diameter main drive friction wheels do you think work best?

Or perhaps I should ask, what diameter are they on say an Epilog, Trotec etc. rotary?

And how much gap between said rollers?

Thanks for any responders.

Greg

[Rodne Gold]

Make the distance adjustable , you can use a spring loaded jockey pulley to take up belt tension if you need to

[Greg Holt]

Thanks Rodney.

I have decided the best strategy is to simply make the friction rollers larger.

Larger rollers should cover a wider range of job diameters.

Greg

[Joe Hillmann]

What type of laser are you mounting this to?
The best size for the rollers depends on how the software works to control the rotary.

If you are putting it in a universal laser or (I assume) any other laser that comes with a chuck style rotary you want the rollers to be as close to the diameter of the average part you plan to do with it. Also since you will have to scale you image at a ratio of roller diameter/workpiece diameter on the y axis I would suggest making the roller diameter an whole number to make the math easier.

If you are putting it in a laser that is meant to run a rotary with rollers than you don't have to take any of that into consideration..

[Rodne Gold]

I really like the idea of those friction rollers in this thread
http://www.sawmillcreek.org/showthread.php?184871-A-different-kind-of-rotary-attachment

[Greg Holt]

If you are putting it in a universal laser or (I assume) any other laser that comes with a chuck style rotary you want the rollers to be as close to the diameter of the average part you plan to do with it.
Also since you will have to scale you image at a ratio of roller diameter/workpiece diameter on the y axis I would suggest making the roller diameter an whole number to make the math easier.

This machine has the LightObject DSP controller. Similar to the Shenhui.

This controller will scale the output for the rotary when raster engraving. Just enter the diameter of the job and the output is scaled accordingly. (when using a chuck type) Unfortunately it does not work with vectors, only raster engraving.

So with a friction roller type rotary it makes good sense to get the ratio right so that it matches the Y axis that it replaces. Then output scaling is not necessary. So vectors will work as they are.

This is not so difficult. Combination of roller diameter and the belt reduction so that the ratio comes out correct.

With some pulleys that I alraedy have on hand, that will mean rollers 115mm diameter. That might be a bit excessive. I will draw it up and see what it looks like.

Greg