RE: [CAD_CAM_EDM_DRO] Re: Stepper motor speeds

It is not as easy as just looking at a particular metal and getting a
required speed and cutting force. As an example, if I cut a piece of
aluminum on my Bridgeport with a 1-1/2" 4 flute carbide insert cutter I
may use a feed of 50 ipm. If I cut the same material on my Sherline with
a 1/4" 2 tooth HSS cutter 10 ipm will be more appropriate. Not only are
the speed vastly different, but so are the required forces. So, it is
not just material but also how much horse power you have, how rigid the
machine is which will limit the size of a cut you can take, etc.

While you can take the engineering approach to this and calculate
everything a much easier approach is to just follow what others have
found to work. If I remember correctly you are setting up a mill/drill
or a Shoptask? If so just use some low inductance NEMA 34 motors in the
400 - 600 in/oz range and you will get great performance that is in line
with what the machines capabilities are. Lots of us have done it and we
know it works. Now if I was designing this to produce a number of these
machines I would get a lot more worried about actually calculating it
all out so I could better understand where I can save a little.

Tim
[Denver CO]

> -----Original Message-----
>
> Dave,
> Thanks for the information, and the reference to
> Mariss's message. I can understand most of it, but his
> reference to "push" has me a little confused. The formula for
> "push" is clear enough, but how do you figure out how many
> inches/minute or pounds are required? Don't both factors vary
> with the material being milled? If that's the case, it would
> be helpful if someone posted a chart with the speed & lbs.
> for various materials. It might help me to make an
> intelligent decision.
>
> Marv Frankel
> Los Angeles