125,000 steps per second

[smarbaga]

i saw a picture on the galery here of a drive
(i forget the brand name, somethig cnc, o yeh deskcnc) that said 125,000 steps per second.
is that many really necessary on a screw type system ?

[ger21]

DeskCNC. If you use servos, it gives you the option of using higher resolution encoders. Another benefit is that it gives you a better pulse stream, which should equate to smoother running mototrs.

In September, Gecko will release their G100, which will ouput 4 million steps per second for 6 axis!

[smarbaga]

can you really tell the difference between 100,000 and 125,000 pulses per second?
thats a pulse every ....... who knows ....

[imserv]

Not much difference,but up to 125,000 steps per second will run a medium resolution encoder (inexpensive) up to the normal design speed of available pmdc servo motors(also inexpensive).

A Sherline mill has a 20 pitch screw. A servo motor, with 2.8:1 belt reduction, and a 500 line encoder has a step ratio of 112,000 steps per inch. 50 inches per minute on this machine is just over 90,000 steps per second.

Most parallel port indexers will not run that fast. DeskCNC will run even faster if you need it for your machine. The DeskCNC hardware is dedicated to stepping, and will create a smooth pulse train from the slowest to the fastest step rates. It's been available for several years.

Fred Smith - IMService
http://www.cadcamcadcam.com/hobby