[tulsah]

I presently have a 2007 IH 12Z manual mill that I am contemplating a CNC conversion for. I fully intend to spec, source and install of the components myself as I have designed and built a sizeable CNC router previously. However, that system employed direct drive steppers for each axis as opposed to the servos I am planning to use for the IH mill.

My question(s) are around the sizing of the servo and power systems. If one uses the typical belt drive reduction in the 3-4:1 ratio range, is there consensus or general rule of thumb as to what size/strength of servo is required for each axis. Two such motors I have run across have the following specs:

1. 850 oz-in, 72 vdc, 8.5 A cont (38 A peak), 4200 RPM

2. 1125 oz-in, 90 vdc, 7.8 A cont (40 A peak), 3200 RPM

Are either of these motors in the ballpark as being suitable for this conversion? Overkill, underkill, etc...? If so, how does one go about determining the appropriate size of power supply to drive all three axis?

Thank in advance for any help.

-Tulsah

[Runner4404spd]

mine runs at 80vdc and has 400 oz in motors on all three axes with a 4:1 belt drive reduction. plus i'm running 3/4 dia screws. i forget the pitch. i think your motors would be able to run with a 2:1 reduction, but you will need a larger power supply. mine is only 20 amps.

Jerry

[skray775]

I have used the DMM ac servos on two builds now... the first was a smaller machine with 300 watt servo's. The second build was a IH clone with the 900 watt kit.

DMM Technology Corp.

I have a complete build thread here on the zone and many youtube vidieo's of the machine.

I really love the DMM setup, simple, quite, no missed steps, and it works.

[arizonavideo]

Both motors will work fine with the right gearing. I ran vary large motors and the only advantage I see is the low noise I get and the cool running. They don't even get warm if they idle all day.

The Z is the axes that takes real power to move and change direction. I would gear for 100 IPM for the Z if you don't add springs.

The smaller motors should change direction faster but I have found that the machine flexes if you have it set to max accelerations on the servos.

[Runner4404spd]

personally mine isn't counter balanced and i didn't use springs. but in retrospect i would counter balance the head and then you can easily use a 400 ozin motor on the z.