Re: ARC's, IKJ & R in Vector CAD/CAM, Art's program

--- In CAD_CAM_EDM_DRO@y..., Alan Marconett KM6VV <KM6VV@a...> wrote:

> Yeah, it probably wouldn't hurt to cut two complete circles, in

opposite

> directions, but I imagine doing G02 AND G03 back to back for LESS

then a

> full circle would cause problems! Probably fail because of the

wrong

> radius? Is there a practical limit or ratio of radius length to
> start/end to determine a radius error?

Absolutely not. You can cut any combination of arcs, both ccw & cw.
As long as the end points are correctly stated and either the R's or
IJK's are also correct. Many controllers will error if the arc
calculation is not within .0001 inch. Some of the older ones had
this requirement, but did not round correctly, so about 1/150 arcs
has to be slightly modified to accomodate the fact the 1.00015 was
rounded to 1.0001, instead of 1.0002. They did the math in hardware
and that was the way it was. More modern controllers, especially
those that are software based, will often have a tolerance that can
be set. Keep it tight though, as a start and end point that are the
same will generate a circle, even is you just wanted to make a tiny
move!

Some controllers do have a limit on the maximum size of arc that they
can process. I have seen some in which any arc over about 40 inch
radius was rejected(maybe the old Bandit controllers?). That is one
reason that the arc-spline in Vector has a setting for max radius
when fitting arcs to splines.

Best Regards,

Fred Smith
IMService