Replacing stepper motors with servos ?....

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cut2cut

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Is there a generic / standard way to determine the size / specs of a servo to replace a stepper motor on a 3 axis metal mill ?

Specifically my brother is trying to determine which ClearPath servos to purchase. ClearPath has a been a bit vague in response to which ones are adequate for his size mill. Its a Wabeco F1210 ( basically the size of a Grizzly G0704) ( roughly 400 pound 3 axis metal mill ). Currently his are all nema 34 : 425 oz inch for the x and y and 700 oz inch for the Z.

Does anyone have any advice they can share ?

Thanks in advance,

Jake
 
The most powerful that he is willing to pay for, if you can get it up to say 500 IPM rapids this will considerably shorten machining time, nothing works better then power.

Rapids are the times when you are not actually cutting, time between cuts is a complete waste therefor money, the faster the rapid moves the better.

Fanuc produces small mill/drill machines that rapid at 1000 IPM, very little wasted time.

I set up and programmed a lathe job today for small parts, 1500 pcs, 3 tool changes per part using a qctp. 4500 manual tool changes, a tool turret would make this much faster, gang tooling would be better for such a small part. Fortunately I do not have to run these parts myself, another person will operate it tomorrow morning, I expect several tool crashes in the first few days. This lathe only rapids at 100 or so IPM., it will crash before it can be stopped in most cases however.
 
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If the current motors are doing the job, then you would be more than safe using the same torque motors in a servo. Unlike a stepper, a servo has a nearly flat torque curve, a stepper's torque drops off dramatically as the RPM increases.

I installed a set of 4 NEMA 34, 750W ClearPath SD servos on a customer machine and it has worked out very well.
 
I've researched ClearPath motors for plans of using them for powerfeeds on my Clausing 8520.
Are you planning on using them in a CNC set-up ???
If you register on the Teknic site, you can go to here: https://www.teknic.com/products/cle...vo-motors/wizard/allresults/#ppsShowPopUp_100
The other way to get there is https://www.teknic.com/
From the home page, hover mouse on Products. A drop down menu appears, select ClearPath then All Models from the next dropdown menu.
Here you will see all the motors with the following comparison categories:
Frame Size (NEMA)
Length (inches)
Peak Torque (oz-in)
Cont.(RMS) Trq (oz-in)
Rated Speed (RPM)
Max Speed (RPM)
Price (USD Qty. 1-9)
 
Thanks for the replies !

Yes, it's for a cnc 3 axis metal "bench top"mill weighing about 400 pounds.

The current motors were never used, this mill is being restored but upgraded with new axis drive motors ( replacing existing steppers that are belt driven ( 3 to 1 ratio currently but that can change )
 
I guess a lot will depend on what you want to do.
Staying with a geared/belt drive system will allow you to use smaller, cheaper motors, but can induce inaccuracies.
Does your mill currently have acme screws or ball screws ???
Direct drive increases speed and accuracy, but requires more power and torque.
There are quite a few YouTube videos by people who converted over to ClearPath motors.
 
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