Re: EMC2 Screw Cutting Problem

Steve.
Threading at about 100rpm upwards, the lathe carriage moves in a
series of pulses - too fast, too slow, too fast, too slow, which
diminish in size until the spindle and carriage are synchronised - I
think of it like a sine wave reducing in intensity until it's a
straight line, where the straight line represents spindle speed and
the sine wave is carriage speed (if that makes sense). Below about
100rpm everything seems to move in harmony. Spindle speed seems
constant.
Shouldn't the configuration of the encoder (in the wizard) tell EMC2
to expect 48 slots per rev and act accordingly and is it not just a
matter of sending out the correct number of pulses (at the right
speed) to the stepper motor/s each time a slot is detected?
I'll try the link you posted as well. Thanks for your help, Martin.

-- In CAD_CAM_EDM_DRO@yahoogroups.com, Stephen Wille Padnos
<spadnos@...> wrote:

>
> OK, glad it's more or less working.
>
> When you say it's "hunting", what are you describing? Do you hear

a

> pitch difference, see the motors speed up and slow down, or

something

> else? Can you see that the spindle speed is relatively constant

while

> the XZ motors are acting screwy?
>
> What kind of spindle speeds are you testing this with? EMC2

calculates

> motor velocities 1000 times per second. If you run the spindle at
> 600RPM (10 RPS), then there are only 480 new positions every

second, so

> about half the time the motion controller doesn't see any

movement. Can

> you try a couple of threading moves at very high and very low

spindle

> speeds, to see if that makes a difference?
>
> I'll point some of the people who actually use lathes at this

problem

> too, and I encourage you to email the emc-users@...
> list. There are a lot of folks who know a lot more than me about
> actually using EMC2 :)
>
> - Steve
>