Re: [CAD_CAM_EDM_DRO] Re: How to go from 2.5 D to real 3 D ??

Hi Chris:

As for Master5 and line,arc differences. After doing many experiments and
try many different methods, I kept coming back to the way EMC does it.
(Those NIST guys are geniuses) Small segment, long segment, arcs, are pretty
much the same thing. Basically a kinematic engine is asked the question,
Where will each axis be in 100uSeconds? Being that the maximum speed is
8192Hz, the fastest an axis can pulse is 100uSeconds from the last puilse.
So , the engine calculates whether or not a moving point on a toolpath
specified by the G-Code will have moved or not on any axis 100uS from now.
If so, pulse, if not, what about the next 100uS period. In this way an arc
is just an extension of the linear toolpath and creates a constant contour
movement. Of course acceleration, deceleration and feed speeds are kept in
mind to calculate the next 100uS periods reach point.
It is more complicated to calculate maximum velocities and blend
acceleration profiles during an arc, so generally, an arc is slower to
calculate, but runs as fast as a series of line segments when pulseing out
of the buffers. The buffers keep the time profile clean by allowing the
engine to slow calculations on an arc, while pulseing the line calculated
from a few moves ago. The engine will catch up while the motors are
decelerating or accelerating or doing straight line segments. Hence,
constant velocity contouring.

Art
Master5 Software
http://users.andara.com/~fenerty/master.htm