Re: [CAD_CAM_EDM_DRO] Re: using a stepper motor for spindle on a lathe

Hi Keith

You might want to consider using a large sized servo motor on the spindle
rather than a stepper. I think your power requirements for this application
are beyond what a stepper is capable of. A servo will have a greater speed
range and available torque than a stepper. Servos are available that take
step/direction input just like a stepper motor. I am not that familiar with
machX although I am sure it can do the job, I just use a different program,
CNCPro. You might need to have a couple of different machine configuration
files depending on what you want to do.

The thing to remember about running a machine's axis' on gcode is that
everything is based on position. So to just run the spindle like a lathe
spindle, you could program in however many revolutions (in degrees) that it
will take to complete the cut. It might be easier to use the analog input
to the servo amp to just set a spindle velocity. Many servo amps have
selectable inputs step/dir, +/- 10v analog, serial communication etc.

What you want to do should be quite feasible.

If you are interested I have a couple of large servo motor/amps which take
step/ dir etc and might work for you. Email me off list for more info.

Regards,
Bob

----- Original Message -----
From: "Keith Clark" <mail@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Friday, January 13, 2006 2:12 PM
Subject: [CAD_CAM_EDM_DRO] Re: using a stepper motor for spindle on a lathe


> In a prior message Seiman said;
> "I do not see why you want to change the spindle to stepper motor as
> each one represent a completly different role."
>
> If I can work through the logic of what is a retrofit of a manual
> woodturning lathe into a CNC woodturning lathe with router option...
>
> I basically have a setup that looks like a metal working lathe with x
> and z axis, except that the axes are bolted onto the side of the
> woodworking lathe which has its own spindle motor. The z axis is the
> carriage that moves down the length of the lathe. The x axis is the
> cross-slide that moves the tool cutting bit at right angles to the
> lathe bed, but in place of the cutter I have a router mounted. The
> spindle motor on the lathe is intact and can be used for high rpm
> normal woodturning.
>
> I would like to then in one instance control the rpm of the motor for
> standard CNC turning with a normal cutting bit or router mounted on
> the cross slide.
>
> In the second instance, I would like to be able to mount an engraving
> motor or router on the cross-slide and to do engraving, fancy
> decorating etc with the spindle now controlled like a 4th axis. In
> the standard mode described in the first instance, the spindle motor
> turns at a controllable rpm either clockwise or counterclockwise. With
> the router mounted, I will be able to rough shapes in very large
> diameter logs and do spiral designs with barley twists or rope like
> creations on smaller pieces. However, in the 4th axis mode, the
> spindle will be stepped in either direction like an axis rather than
> like a lathe spindle.
>
> My problem is trying to understand how Mach3 will deal with these 2
> setup options. It seems to me that a stepper motor could offer both
> options. Perhaps the stepper motor could handle lower rpm standard
> turning jobs with the router mounted and when needed the higher rpm
> jobs would be done with the original spindle motor controlled
> manually. I realize that there is a resolution issue with larger
> diameters in the 4th axis mode that might require a significant gear
> reduction.
>
> Again, this router table is mounted to a woodturning lathe with an 8
> foot by 30 inch diameter capacity. That is about the best I can do to
> describe the situation. I appreciate eveyone's feedback and suggestions.
>
> Thanks,
> Keith Clark
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, Seiman H <seiman_h@y...> wrote:
> >
>
> > you can have a 3 axis machine with rotary 4th axis but the spindle
> still independat it usually works with Z axis in this case which do
> not exists at your lathe.
> >
> > Seiman
> >
> > Keith Clark <mail@t...> wrote:
> > I am wondering if I can use a stepper motor to turn the spindle of a
> > lathe. I am using Mach3 to control the 2 axis router machine that
> > mounts on the woodturning lathe. I will do very slow rpm work,
> > shaping vessels with the router machine. It seems like Mach3 is
> > capable but the docs do not specifically discuss stepper motors but
> > say a step and dir controlled motor will work. Does anyone see a
> > problem with this approach?
> >
> > Thanks,
> >
> > Keith Clark
> >
> >
> >
> >
> >
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timg@...
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[Moderators]
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> OFF Topic POSTS: General Machining
> If you wish to post on unlimited OT subjects goto:
aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if
you have trouble.
> http://www.metalworking.com/news_servers.html
>
> http://groups.yahoo.com/group/jobshophomeshop I consider this to be a
sister site to the CCED group, as many of the same members are there, for OT
subjects, that are not allowed on the CCED list.
>
> NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM.
DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
> bill
> List Mom
> List Owner
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>
> Yahoo! Groups Links
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