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Author Topic: Servo for lathe spindle ?  (Read 18200 times)

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Servo for lathe spindle ?
« on: September 12, 2014, 09:47:52 PM »
 Hi everybody,

I am refurbishing my Wabeco ccd6000 lathe with servos in X and Y axis.
I am just starting to use "servos" for the first time and i am installing 2 Delta ecma servo motors AC to the x and y axis on my old wabeco lathe.The controller is csmio - a  with the enc and mpg modules.
For the spindle i would like to improve and change the original motor with either a ac motor driven with a vfd OR a AC servo and driver.The spindle is belt driven so i would like to either use a toothed belt instead of the original one which is not toothed.I have seen servo driven spindles but some people are saying that -apart from spending a lot of money for a servo and driver-by belt  there is too much resonance and is NOT going to work(i.e. the connection motor to spindle should be rigid).I would like to be able to have the servo precision and even be able to do rigid tapping (which i thing is only possible with a servo driven spindle).
The original motor is a dc 1400W motor 5000rpm getting reduced by the pulleys to 2300rpm and rpms are adjusted by a potentiometer from 250 to 2300rpm.Or if i want to go lower than that i have to change the pulleys ratio and go from 50 to 500rpm.
 So my 2 questions are:( if cost is not so important) :
1.will it work if i install a servo and be able to drive from 0-2300 rpm with enough torque even in very low rpm? and will i be able to do rigid tapping?
and 2. what servo (i.e. how many KW-rpm) should i buy to use in the spindle for that?
Please help...

Offline Dan13

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Re: Servo for lathe spindle ?
« Reply #1 on: September 13, 2014, 03:31:13 AM »
I am using AC servos for driving the spindle on two lathes and a mill. All are timing belt driven. I am VERY happy with them, and if money is not an issue I would use AC servo on any machine I shall ever do. I can do rigid tapping on all the machines, and some other things. Check out this video, where I am cutting a hex on my wee lathe:
http://youtu.be/DajrTlI8IWA

Also, I should note that as far as I know the CSMIO supports rigid tapping with any spindle motor provided it has an encoder.

Delta servos are excellent. Properly tuned you should not experience resonance. However, if you belt is too long you may need to use some tension wheels along the way. AC servos have full torque starting from zero rpm. You can run it in the rpm range you ask. Your original motor 1400W @5000rpm provides a nominal torque of about 2.6Nm. If this satisfies your needs, then this is the torque I would go for when picking a new motor.

Dan
Re: Servo for lathe spindle ?
« Reply #2 on: September 13, 2014, 10:54:01 AM »
 Hi Dan 13,

VERY IMPRESSIVE!!

What controller are you using?
And what software to design-make the g-code?

Thank you for your help very much.You see i am totally new to servos and i need all the help i can get...

Best regards,

Tasbiz

Offline Dan13

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Re: Servo for lathe spindle ?
« Reply #3 on: September 13, 2014, 02:56:22 PM »
I am using a USB SmoothStepper on the mill and the lathe in the video. The other lathe has the Ethernet SmoothStepper. If you're referring to the gcode in the video cutting the hex, it is a parametric Gcode I wrote.

Dan
Re: Servo for lathe spindle ?
« Reply #4 on: September 27, 2014, 06:42:24 PM »
Hi Dan13 and everybody...
I have finished the controller and managed to tune the servos (just the servos without the controller CSMIO/IP-A) but i CANNOT make the servos work with Mach3 and the CSMIO.I dont know what to do.I am not even sure that the connection is OK.I can jog the servos from their drives OK but from Mach3... NOTHING!! :'( :'( I have managed to get the leds on the controller to show ready state BUT if i try to jog the motors nothing is happening.I am LOST i am LOST...
Can please anybody help?

Reagards to all,

Tasbiz

Offline Dan13

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Re: Servo for lathe spindle ?
« Reply #5 on: September 28, 2014, 03:51:59 AM »
What servo drives are you using? You need to set them to analogue input if you're using the CSMIO/IP-A.

Dan
Re: Servo for lathe spindle ?
« Reply #6 on: September 28, 2014, 04:34:33 AM »
Do you mean Torque mode?
How do you set analogue input?
I am using delta drives...

Offline Dan13

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Re: Servo for lathe spindle ?
« Reply #7 on: September 28, 2014, 05:20:20 AM »
Please provide a link to the drive you're using.

Dan
Re: Servo for lathe spindle ?
« Reply #8 on: September 28, 2014, 07:01:31 AM »
http://www.delta.com.tw/product/em/motion/motion_servo/motion_servo_product.asp?pid=2&cid=1&itid=6

I managed to make them work (i found how to switch them to torque mode)but they work realy strange from mach3.It seems that no matter what i do with the settings of either mach3 or csmio when i press the jog button the axis moves in very high velocity till it hits the limit button and stops.Could it be that i am using windows 8.1 64 bit?
Re: Servo for lathe spindle ?
« Reply #9 on: September 28, 2014, 07:03:12 AM »
it appears in the diagnostics that win 8.1 and csmio are connected ok though...