Re: [CAD_CAM_EDM_DRO] List goals/aims/results?

> I, for one, would like to know if I can get more than 10 IPM with my
> existing hardware (Sherline mill, Sherline motors and mounts, Mauch 2A
> board, 24V/8A power supply, counterbalanced head, stock leadscrews and
> nuts, Mobil One synthetic grease, all described in earlier posts) by just
> switching from the default (since it's free...) DeskNCrt to a different
> software.

I'm far from an expert, but it would seem to me like there are 3
possibilities:

1) the software can't generate steps any faster on your computer
2) the driver/motors can't go any faster at this voltage
3) the driver/motors could go faster, but not without loosing steps
under load

As a start, what is the failure mode when you tell it to go faster
than it does? Does it keep moving but not faster? Or does it stall
or move erratically? What if you write a tight loop, even in basic,
to twiddle the step pulse on the parallel port? Can you change
between full and half step mode?

If this is right on the limit of what your drive/motors can handle at
the present voltage (ie, it stalls or moves erratically when you try
to go faster) there might be some benefit from a program that profiled
motion with proper acceleration and deceleration times, but my
uneducated guess is that this would be more likely to help on a
bridgeport-sized machine than a sherline-sized one moving the vicinity
of 10 ipm.

Quick calculation: on a stock sherline it takes 40 turns per inch.
With a 200 step/revolution motor in half step mode that is 16000
steps/inch. 10 ipm is 1/6 inch per second, so that's about 2666
steps/second... Or put another way, 400 rpm. If the motors are small,
this very well might be the limit where the torque would fall off too
much to effectively run the machine.

I'm sure others will give you better advice based on their experience.

Chris

--
Christopher C. Stratton, stratton@...
Instrument Maker, Horn Player & Engineer
22 Adrian Street, Somerville, MA 02143
http://www.mdc.net/~stratton
NEW PHONE NUMBER: (617) 628-1062 home, 253-2606 MIT