Re: [CAD_CAM_EDM_DRO] Re: Timing Pulley Accruacy and Servo shaft runout

Polaraligned wrote:

>Hi Les,
>Yes the one that measured .005 at the end of the shaft was a
>new motor and appeared undamaged. But it was by far the worse
>one. The other motors measured in the .002 range. Still more
>than I expected.
>When you say anything below .0005" should be fine, did you mean
>anything below .005"??
>.0005" is on the otherside of the spectrum and a very small
>runout for a timing pulley. I would have to both turn the motor
>shafts and bore the pulleys to keep that.
>
>If I did the math right, using the runout of .005" with the
>motor pulley being 1" approx dia., I get an error of almost
>.008". This almost sounds like too much error for that runout.
>
>(.005/(3.14*1))*5 = approx .008
>
>

The last operation should be division, as the leadscrew will reduce movement
per revolution. A total indicator reading of .005" is an actual
eccentricity of
.0025". So, I think a more accurate prediction would be .0025/(3.14*1)
/ 5 =
.00016" I interpreted the .0005" to be the linear error result of the
pulley
eccentricity. and agree that when it gets down there, you can ignore it.

Most likely, the pitch errors in your leadscrews exceed that by a
significant margin.

Jon