Ok, I know very little about using a lathe, I have two a Mini 4x12 and a Craftsman 12x36 but I have had the time to actually use them. I have done some turning and parting but haven't actually made anything.
So I was wondering about facing something was mention the other day but it didn't register with me?
as Hey This Is Something You Need to Know pay attention.
Ok, when one is facing a end on your lathe the center turns at a different RPM than the exterior,
is that correct??
Sort of. The RPM is constant. the issue is the surface feed rate, which depends on the radius and the rpm. When you look in a references such as Machinerys Handbook the ¡®Speeds¡¯ part of ¡®Speeds and Feeds¡¯ is always expressed in terms of surface distance/ time unit, usually feet or inches (or cm or mm) ?per second.
In the absence of some means to vary the spindle speed while facing or turning the usual approach is to pick someplace in the middle (for facing) or base it on the outer diameter of the part you¡¯re turning.
With a properly controlled electronically driven spindle you can adjust for this on the fly based on the tool position in reference to the central axis of the spindle.
In practice on a lathe with a few inches throw, like ours, this really doesn¡¯t make much difference at all, because the optimal feed rates are always expressed as a range, based on the material.
Well in thinking about stepper motors and different speeds I wondered if anyone had used?
? This Arduino library allows one to set different acceleration/deceleration rates.
I have followed the for a couple of years and there appears to be good support.
I would suppose one would use this separately from any ELS program, unless the ELS program allowed one to implement new features.?
This library would have to be incorporated into the ELS program itself, not used separately; and this library is designed to change the rates of change at the beginning and end of a movement to avoid sudden and jerky movement that could stress structures attached to the stepper motor. This kind of control is widely used in CNC router-type applications; I'm not sure how much it applies to a 2D system like an ELS.
--?
Bruce Johnson
"Wherever you go, there you are." B. Banzai, PhD
