need help calculating motor torque for gantry

[eloid]

im looking into using ballscrew to move my gantry on mycnc design, I what to know what is min size motor i should use?


i havent bought any motors yet, or ballscrew, im looking for advice, does anyone have a example of the calculation i need to do.
Im debting if i should use dual motors on Y axis and or do a 4:1 gear ratio.
The other question is what pitch is best suit for 4:1 with out lossing to much speed.? What is most econmical size of ball screw dia. 1/2 or 5/8

Does length of y axis play a part... im thinking the cuting area to be
6 feet yaxis 5 axis enough area to cut half a sheet of 4x8 plywood.

Im planning to use my cnc for wood working with some light alumumin
cutting.

[Eurisko]

You'll need to know the weight of the gantry.

Here's a link that will fill in the details:

http://www.cnczone.com/forums/showthread.php?t=31815

[ger21]

http://www.orientalmotor.com/support..._recommend.htm