I am cutting spirals on a wooden cylinder. If I only cut one spiral it works fine, and it returns to where it started. if I cut multiple along most of the length of the cylinder, one of 2 things happens:
The job finishes but the laser travels about 100mm in the negative Y direction
Alarm 1 is raised and the laser hits Y zero hard!
When Alarm 1 is raised it burns within the area defined by Framing. Any idea why it believes that a limit switch has been triggered? Smacking against Y zero can’t be doing any good. helix1.lbrn2 (5.6 KB)
Please note the values in the Lightburn file are to get the spiral to run along the length of the cylinder. The actual cylinder diameter is 18 mm.
You have a claimed 400mm^2 workarea. on your machine. I speculate you are slamming into the back rail at 4000mm/m with no room to decelerate, losing position accuracy, and then it is hitting the limit switch with some travel left over.
I set my workarea in Lightburn about 5mm less than the max travel for each axis. This ensures I have enough room left over for stopping and overscans.
5mm is about 2/10ths of an inch, hardly a sacrifice.
The 400 represents the distance travelled around the cylinder. It is not a linear distance where the laser will hit a physical limit switch. I think what is happening is that since 400 is greater than the set x-size that is triggering the Alarm. The actual bed size should be 390 x 390. I didn’t think that the helical distance travelled in the x-direction on the rotary would create an error. If that is the case then for a given spacing between the helical rings I can’t exceed 390 for the helical distance or that will be interpreted as distance travelled in the x-direction. Surely this should not apply when using the rotary. if I wanted a tight spiral along a 6" cylinder I would need to do it in several steps, which leads to positioning issues.