Torque Ratios?

[SteveT44]

I'm designing a gantry router and will be using two motors/ballscrews on the X axis. My question is, is there a recommended ratio between the dual X axis motor torque and the single Y axis motor torque? For example, would I use two 400oz steppers on X and then a single 800oz stepper on Y, or just use 400oz motors all around?

My router will be similar to the K2CNC 50"x50" model. Can anybody recommended minimum motor torque for cutting 3/4" ply? The ballscrews have a .5" lead.

TIA

Steve T.

[jeffs555]

A .5" lead ballscrew will generate about .71 pounds of force for each oz-in of stepper torque. A 400 oz-in stepper would generate 284 lbs of force just before it stalled. That sounds like a lot of force, but the torque on a stepper drops off at speed. You would have to look at the torque curves for your steppers to see what force they would have at the cutting speed you want.

As for the dual steppers on the x axis, when at the edges, unless one motor can handle all the force, there will be racking forces on the bearings. How much racking force you can stand depends on your bearings.

There is no quick answer. To be assured that it will work, you need to go through a lot of calculations.

Jeff

[bradyfb]

Hey, Just woundering what diameter ballscrew you are useing with the .5 lead?

[SteveT44]

.75"

http://cgi.ebay.com/NOOK-3-4-Ball-Sc...QQcmdZViewItem