# Roller diameter and MM per rotation

Why isn’t the roller diameter directly correlated to the MM per rotatation.
Like Dia x Pi = circumferencec = MM per rotation?

Last night I was doing some test burns on a cup trying out some different speeds with a 10mm x 10mm square and some text. Was coming out at 9 mm in the Y direction. this morning I try a new setting and my 10 mm is coming out 5 mm in the Y direction. I drew a rectangle that matched the circumference of of the cup and ends match up great, maybe off by 1mm but the 10 mm square is turning out as a 10mm x 5mm rectangle.

The only rotary that needs the circumference is a ‘chuck’ type.

With a wheel (roller) type the circumference is moot as the roller (wheel) rotate for 1 inch, so will the surface of the mug/cup…

With a roller, the setup is for the motor to turn 1 rotation, then apply the ‘ratio’ of the drive belts (gears) to the steps… causing the roller to rotate 1 complete turn. The roller diameter/ratio are used to compute the resulting surface speed.

Make sense?

Yours doesn’t make sense, if it loses 1/2 it’s distance on one run, then other art will properly produce a rectangle… some problem with configuration or ?

Where did you get the data for setup of your rotary… I assume it’s a wheel (roller) rotary.

It is a roller type. So the MM per rotation has nothing to do with the roller and is MM per rotation of the stepper motor?

Not exactly…

The setup for a generic motor driver for a rotary is to determine steps/rotation (mm/rotation, they are different) then apply the ratio of the drive system to the driving wheel. This will change the ‘one’ rotation of the motor to ‘one’ rotation of the drive wheel.

With the drive wheels diameter, the software can compute how much it has to move the wheel to rotate the object properly.

What you want is the wheel to rotate one direction then back…

Sorry if I confused you.

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.