Bridgeport Retrofit Using Brushless AC Servo Motors?

[Eric]

I have a few Brushless AC Servo Motors and drivers that I was thinking of using to convert my Bridgeport knee mill to CNC. Can anyone tell me if they are good enough for this application?


Y-2023 series
4500 RPM
Power 0.91KW
Continuous Stall Torque 2.5 N-m (22.5 lb-in.)
Peak Stall Torque 7.1 N-m (63 lb-in.)
2000 Count Optical Encoder
3.5" bolt circle mounting


I have only have one of these....
F-4030 series
4000 RPM
Power 1.4KW
Continuous Stall Torque 3.5 N-m (31 lb-in.)
Peak Stall Torque 11.3 N-m (100 lb-in.)
2000 Count Optical Encoder
Nema 56C mounting

Here is a (large) PDF for both Motors
http://www.ab.com/manuals/gmc/GMC-SG...4_1_Motors.pdf


Thanks.

--Eric

[Al_The_Man]

I have a couple of Excello knee mills with brushed motors that size, you could put the larger size on the Y as this motor usually carries the X table also. Mine are toothed belt drive with 2:1 reduction.
Al

[Eric]

So what else do I really need to convert this to CNC (control wise)? I have the servo motors and the AC drives for them which will accept step and direction signals. Do I just need something like Mach2 and hook up the parallel port of the PC to AC drives?

Or do I need some kind of multi axis controller PCB?

[Al_The_Man]

Depends what you want to spend and how sophisticated a system you want. Don't forget you will also want ball screws on all three axis and will need to add a Z axis control to the quill.
Al

[Eric]

I don't need something super expensive or sophisticated since this is not for produciton work or making money. I just need something so I can cut metal for my projects, motorcycles, jet skis, 4x4s, etc. I want to be able to cut arcs, large circles, 3D shapes, etc. I don't know if that means I need something more powerful than Mach2 and step and direction from a parallel port or if I need a multi axis motion card???? As far as the servo motors go, I think a 5TPI ballscrew with a 2:1 pulley reduction will give more speed than I could need ~ 400 IPM = 4000rpm / 5 TPI / 2:1 reduction.

I just want to mess around with an x-y CNC first and then I can worry about making the quil the z-axis and maybe my rotary table 4th axis.

I mostly machine aluminum and mild steel.

Thanks for any input.

[unterhaus]

I am renovating a Bridgeport using Electrocraft motors, one is a 4030. This is a high end setup particularly well suited for CNC. I'm using Electrocraft drives which can take step and direction. EMC, Mach2 or Turbocnc will all work with this setup, and you avoid spending $700 on an interface card. Suggest you go with a breakout board for the parallel port.

You might want to check out the project logs for mills, there is mine and one that actually a conversion, which sounds like what you are doing. You can find it here: http://www.cnczone.com/forums/vertical_mill_lathe_project_log/

[Eric]

Yes, these are very high end (expensive) motors and drives. I have three Ultra 100 series 2KW drives for each of these and they will take step/dir as inputs for getting your system up an running fast. They also accept +/-10V analog (16bit) inputs and have encoder outputs so you can hook them up to a motion control card later on down the road.

Here is the PDF for the F-Series motors:
http://www.ab.com/motion/ec/f_series.pdf

Here is the PDF for the Ultra 100 series drive:
http://www.ab.com/motion/drives/1398-1.0.pdf