View Full Version : Laser won't cut a perfect circle

Wilbur Harris
06-28-2016, 11:40 PM
The ends meet, and it's close, but not perfect. In fact, it's noticeable if you give a second look! How can I adjust this thing to get a bit more toward a real circle.

Shenhui Laser
RDWorks software

Rodne Gold
06-29-2016, 1:48 AM
Use the lead in and lead out setting , this basically starts and ends the circle beyond the actual circle and provides a circular cut without notches

Rich Harman
06-29-2016, 3:41 PM
That's due to backlash. You may find better results when the cut point starts/ends at different points on the circle.

Wilbur Harris
06-29-2016, 8:31 PM
I'll try to figure out what Rodney is talking about but I believe I can do what Rich suggests right away...maybe not....

Rich Harman
06-29-2016, 8:50 PM
To experiment with different start points you would use the node edit tool, select one of the nodes and then break it apart. That way when you rotate the circle the endpoint rotates along with it. If you don't break it apart then it may not affect where the laser begins to cut it.

Kev Williams
06-29-2016, 9:28 PM
Lead-in/lead-out is aka tangential entry/exit.

This is a cut path with lead in/out:


the cut starts at the tip of the arc, which passes the first/last point, then upon completion, the path continues beyond the first/last point in the second arc...

The idea is for your tool, knife, plasma flame or laser beam to never be stopped at the first/last point, and ideally leave an invisible transition...
It works wonderfully when vinyl cutting with a swivel-knife machine, this insures the first/last point will be cut, which really helps with weeding.
I've never actually tried it with laser cutting, I don't do very much high-def vector cutting...

None of my laser's software or drivers have this function (that I know of), my old Casmate created the above...

Wilbur Harris
06-30-2016, 1:02 PM
Thanks Guy's! Give me a day or two to work on this and if I fix it I'll get back here and say so. The darn thing is pretty close as it is....

Bill George
06-30-2016, 2:14 PM
I have owned and used two laser engravers, never had to do this on either. My CNC plasma cutter, yes.