[V8 BUG]

This is my bridge mill design concept.
I already have the base plate which is a welded aluminum structure 28"x67" with a 1" top plate and 1/2" double "x" pattern for support. It has been stress relieved and blanchard ground top and bottom.
I have all of the linear rails which are thk hsr25's as shown.
I also have the x plate which is surface ground steel 1" thick and weighs approx 120 lbs.
I will need to fab the uprights(3"1/4 wall tube) and the "y" cross beam (6
" channel)
The y axis plate and z axis plates will be aluminum.
So I was thinking of ordering a ball screw package off ebay from linearmotionbearing which comes with 3 5mm lead screws nuts and bearing blocks with ends machined on the screws.
Gecko drives and stepper motors in the 640oz in range.
This is where I am not sure what to do. I plan to machine aluminum and softer materials like wood and foam. Do I need bigger motors to run cutting at 120ipm and rapids at around 400ipm? I may load the table with a bridgeport vice which is about 75lbs but am not sure. I really don't care if its not really fast as I am use to cutting with huge old duplicators that are maxed out at 60ipm cutting.
As for a spindle I am not sure if I will use a wood router or build my own spindle yet.
Any suggestions would be appreciated,
Thanks Kevin

[ger21]

Generally, the bigger the motor, the slower it goes. If you want to go faster, use smaller motors. You'd probably get pretty good performance from a G540 and 380 oz steppers. The only issue you might have is acceleration.

[V8 BUG]

Thanks for the reply....I was not thinking that a small motor like that would move such a heavy x axis load. The Gecko 540 drive looks really neat and complete. That would make things easier with that drive.
Kevin

[ger21]

You really need to do the calculations to see home much force you need to move at the speeds you want, and what motor will give you that force. I don't know for sure that that drive/motor will do that.

[V8 BUG]

I wanted to do the calculations but I cannot find the .xls sheet that one of the members posted. I don't want to spend money where I don't need to or buy something that will not work or I cannot make it work. So if anyone can direct me to that document I would appreciate it. I did download the parker dos program but cannot make that work on my xp computer for some reason.
Kevin