Re: motor/leadscrew/ps recomendations and calculations

You really might want to go with the transformer and rectifier for you
stepper power. I have a 24 volt 8.6 amp switching power supply I WAS
going to use with Dan's 5 AMP controllers. The operative word here
is WAS, because when I could get it to actually provide motion, the
torque was almost non existant. Holding torque was great, but not the
moving torque. Just for kicks, after exchanging email's with Dan, I
replaced the 24 volt switcher with two 12 volt lead-acid batteries in
series, WOW what a difference. I now have loads of torque in motion,
and the speed is fine and can most likely be pushed even higher. I am
currently usind DeskNC on a 486-66 PC with MS-DOS 6.2.2

The 24 volt switching power supply will go up on ebay this week and I
will purchase a transformer and other power supply components from Dan
to do the power supply correctly. By the way, my 5 volt DC comes from
a 300 watt PC power supply and that seems to be fine, but I won't try
to use a switcher for stepper power again! (I don't need that kind of
stress in my like!!)

John Guenther

--- In CAD_CAM_EDM_DRO@egroups.com, "Richard Spelling" <richard@s...>
wrote:

> I've built a prototype cnc router using 3/8-12 leadscrews, Dan's 2

amp

> driver, and the following motors:
> X - 210ozin from Dan Mauch
> Y - 180ozin, high torque (read SLOW), from www.amsicorp.com
> Z - ???ozin, salvaged from a printer
>
> The power supply is an old AT supply.
>
> For X I can get about 12 ipm before the motor stalls
> For Y I can get about 8 ipm
> for Z I can get about 10 ipm
>
> I'm using half step mode, with 4800 steps per inch and CNCPro.
>
> I'd like to increase the speed, but still have at least 50 lb of

linear

> force available.
>
> I figure if I went to 3/8-4 screws, I would still have 1600 half

steps per

> inch, more than enough for me, and this would bring the machine

motion

> further down into the motors torque curve, but I'm not sure if this

would

> kill my linear force or not. What is the formula for calculating the

linear

> force available at different leadscrew pitches and motor ozin?
>
> Another option I'm considering, at about the same cost, is to get

another of

> Dan's motors for Y, and increase the voltage of the power supply.

Under load

> right now, it puts out about 9v. Dan suggests I would get a 50%

increase in

> speed from the motors by going with an 18v supply. This would give

me about

> 18ipm for X and Y. This route would keep the high linear force, at

the cost

> of higher screw rpm and a lower top speed than the new leadscrews.
>
> What I like about the AT supply is the readily availble 5v for limit
> switches, but I suppose I could pull 5v off Dan's board somewhere

for the

> same purpose...
>
> Suggestions? Comments? Questions?
>
>
>
> Richard Spelling, http://www.spellingbusiness.com/boats
> From the muddy waters of Oklahoma