How's this for Power....50 millionths to boot ...

natchamp_87 wrote:

>
> According to Aerotech's motor calc spreadsheet I will have the
> following speed for travel: 142 in/sec. I know this is overkill and
> I certainly won't start out at anything close to it, but it is kinda
> cool to see the power of these motors.

> Some of the input variables are:
> Load - 200lb
> Ballscrew lead - .200
> Accel time - .1 sec
> Decel time - .1 sec
> Thrust force - 1,000 lbs

I recently got my big J&L lathe (12,000 lbs, 30 HP spindle)
moving the Z axis carriage (about 1500+ lbs) with a 4000 count
encoder on a 2" dia 5 TPI ballscrew driving 2 HP servo motors
with the http://www.geckodrive.com G340 driver (in *1 mode).

The steps are demonstrable to 50 millionths (of an inch). Not bad
for a 1500 lb object! Next week the X axis is going in, with a
25 millionths step (in radius, thats 50 millionths in diameter).

The computer is an AMD350 running DOS & TurboCNC from
http://www.dakeng.com/turbo.htm and hits about 45,000 steps/sec
which gives me a speed of about 2.25"/sec with a 1500+ lb carriage.

I use my own 1.5KW power supply of course (to drive the Geckos),
but wired for 240VAC/1ph input. As a side benefit, this allowed me
to test at 'half power' using 120VAC/1ph input (which gave 37.5VDC out
instead of the normal 75VDC output).

Doug Fortune
http://www.cncKITS.com















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