Re: [CAD_CAM_EDM_DRO] EMC and Rounded Corners

"Toddy, Terry L CUBA" wrote:

> I have my CNC plasma cutter working. I cut the first pieces last night. All
> went pretty well for a first try with a "live" torch.... but, I programmed
> sharp corners and EMC rounded them all with about a 3/8" radius. I am
> cutting at 200 IPM with 8in/sec^2 accel. Is the rounded corners due to slow
> accel or is it a constant contouring feature? If it is a feature how do I
> disable it? I realize the torch will burn the corners off some, but there is
> definitely a tool path issue here.

8 in/sec^2 may not be enough acceleration for this feedrate. 200 IPM = 3.3 IPS,
so you will need perhaps 12 In/Sec^2 or more to get pretty sharp corners.
The onter thing is that EMC defaults to a "smooth" mode where the next move
is interpolated in as soon as the deceleration from full programmed feedrate
begins on the last move. The greater the acceleration specified, the shorter
the distance this smoothing takes place over. But, you can go to "exact stop"
mode, by placing a G61 before this section of the program. (You can go back
to the smooth mode with G64.) I don't know whether the exact stop mode will
cause nasty burns where it pretty much stops for a moment.

Jon