Help Please: Gear and linear speed calculation

[BigBrand]

Big thing that jumps out to me, is you're using pulley diameters, not number of teeth.
Although diameters will give you a rough calculation, it's not going to give you an exact one.

You also need to count the teeth on the pinion, and find out what pitch the rack is.

Ahhh i see. Rough calculations for now is fine but yes ill count the teeth. Also what difference does the amount of teeth on the pinion make? I thought it was just the outer diameter (circumference) of the pinion that sets the speed?

[m_c]

Don't cripple a machine this size with steppers.
Servo's aren't that much more expensive, and will be far better than even closed loop steppers.
https://www.aliexpress.com/store/gro...513054652.html
I'd probably guess 1 or 1.2KW would be a reasonable match, but I'm sure Jazz will give you a better answer.

Ahhh i see. Rough calculations for now is fine but yes ill count the teeth. Also what difference does the amount of teeth on the pinion make? I thought it was just the outer diameter (circumference) of the pinion that sets the speed?

Technically the Pinion pitch diameter is the figure you need, however it's easier just to find out what pitch (it'll either be MOD or DP) the rack is, and the number of teeth on the pinion, then multiply the number of teeth by the pitch.