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Author Topic: spindle encoder and breakout board question, qaud encoder?  (Read 3215 times)

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spindle encoder and breakout board question, qaud encoder?
« on: November 17, 2007, 11:07:24 AM »
Does mach support a qaud encoder on the spindle or just the single pulse/tach type ? I would like to experiment rigid tapping on the mill so I think the qaud encoder will be required,
I am also converting my 14x40 lathe to cnc and am curious about reccomended breakout boards,  I have been happily using deskcnc on my other cnc machines but want to give mach a try on the new lathe. Any suggestions or advice on breakout boards welcome , I have an ncpod board but I am guessing all the bugs to interface with mach fully are not completley ironed out . I am considering the board form cnc4pc , how does the encoder for the spindle interface ?

Also curios how to index a cat40 spindle correctly with mach for tool changes so that the drive key is in the proper place

Thanks in advance for any advice
« Last Edit: November 18, 2007, 01:30:38 PM by panaceabeachbum »

Offline Hood

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Re: spindle encoder and breakout board question
« Reply #1 on: November 17, 2007, 05:32:34 PM »
The smooth stepper board which will be released soon uses an encoder for the spindle, or at least I think it does  ::)

Hood

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Re: spindle encoder and breakout board question
« Reply #2 on: November 18, 2007, 10:41:09 AM »
Does you mill have a servo motor for the spindle or 3ph synchronous motor??

I don't beleive that MACH can ridig tap in the conventional manner. We have acheived great success with SRT(semi rigid tapping) down to a 1 thread tolerance. But it requires the use of a T/C tap holder as Mach has to resync as the spindle reverses and that takes from 1 to 2 turns of the spindle. ANd you are limited in speed due to the fact you have to stop and start the high inertia motor and that takes time even with dynamic braking.

It can be done IF the spindle is a servo BUT it requires the use of an axis renaming routine in the gcode which makes it unconventional in its use. That way you can also use the encoder index to index in the slot for the tool changer.

(;-) TP
Re: spindle encoder and breakout board question, qaud encoder?
« Reply #3 on: November 18, 2007, 01:34:15 PM »
my spindle motor is a conventional 3 phase AC  motor with VFD  . I was hoping for qaud encoder input so I could try mach on a large milling center but the cat40 spindle requires precise indexing for tool changes because of the drive key, rigid tapping was hopefuly going to be a plus .

Is there any plan/hope of a qaudreture encoder interface in the future?