RE: Shinano Kenshi 24VDC Servo Motor with Encoder Res: 500 Pulses/Rotation I have databook

According to my rough calculations, you can get 64 lbs of thrust using these
motors at the rated torque with the following assumptions:

- 2:1 reduction from motor to 5 tpi ballscrew, and 90% efficiency overall
- effective pitch = .100" motion per turn of screw (in/rev)
- 1 kgf-cm = .8679 lbf-in
- rated motor torque = 1.3 kgf-cm = 1.13 lbf-in = 18.1 oz-in
- screw nut thrust force:

Force(oz) = [torque(oz-in) * 2 * 3.14 * efficiency(%)] / pitch(in/rev)

= [18.1 * 2 * 3.14 * .9 ] / .100

= 1023 oz.

= 63.9 lbs

This would be the thrust force of the nut pushing on the table, assuming
there are no additional torque loads on the screw. This does not include
any friction losses due to the slide system (dovetail ways, etc) or masses
(z axis weight, inertia). Once you know this info and the cutting loads you
want to see, you should be able to calculate the max. acceleration potential
of the system. I have no idea what good acceleration would be for machine
tools. Anyone??

Carlos Guillermo

> -----Original Message-----
> From: Jon Elson [mailto:jmelson@...]
> Sent: Tuesday, February 08, 2000 3:10 PM
> To: CAD_CAM_EDM_DRO@onelist.com
> Subject: Re: [CAD_CAM_EDM_DRO] Shinano Kenshi 24VDC Servo Motor with
> Encoder Res: 500 Pulses/Rotation I have databook
>
>
> From: Jon Elson <jmelson@...>
>
>
>
> Multi-Volti Devices wrote:
>
> > From: "Multi-Volti Devices" <multi-volti@...>
> >
> > If anyone wants full data sheets for this motor, I just got a catalog
> > in the
> > mail from Shinano today, by coincidence.
> >
> > How much work can one really do with a 40W servomotor, compared to a
> > NEMA 34
> > or 42 stepper?
>
> Not much. Might be somewhat comparable to the NEMA size 34 stepper
> (single stack).
> The servo motor has a peak rating, which is usually several times the
> continuous rating,
> and so it can actually accelerate and brake a bigger load than you would
> think from the
> 40W rating, which would be the continuous number. This might be fine
> for the smaller
> machines (Sherline, Taig, etc.). Especially with a belt reduction in
> the range of 2:1 to 4:1,
> and ball screws, I would expect it to do a fine job.
>
> I'm using 1/8 Hp (continuous) motors on my Bridgeport, with 2.5:1 belt
> reduction and
> 5 TPI ballscrews. I have broken 3/8" end mills off cleanly when a clamp
> bolt crashed
> into the (stationary) tool! And, that was without even tripping the
> servo amp offline!
> So, I think motors of this size are sufficient for the Bridgeport. 1/8
> Hp is just under
> 100W.
>
> Jon
>
>
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