Are there plans to bring drag knife support to version 4?

Are there plans to bring drag knife support to version 4?


I thought drag knife only needs extra positioning GCODE and is otherwise the same as any other cut job? I may just not know enough about it though.

Nope. It has to do some nifty arc exit on each close angle vertex to avoid ripping material

@Jorge_Robles Ahh. Then the videos of drag knife cutting of cardboard and chipboard I’ve seen were just sloppily done. All of them ripped material when turning.

@Jorge_Robles FWIW, this might be helpful:

See the Excel file link labeled, “G-Code Swivel Program”

@Jorge_Robles I’m super keen to volunteer, once I actually wire my CNC up. Got the physical parts assembled now, just have to find the time to read up & do all the wiring.

Thanks… was meant to coders :slight_smile:

@Jorge_Robles hahaha fair enough

I’m guessing that drag knife support isn’t going to be added to LaserWeb 4?

It isn’t that it tears when turning corners. That is because the material is too thick and the knife is at too shallow an angle. It is that the tip of the cutter is behind the centerline of rotation. So the knife always lags behind anything but a straight cut. Arcs and circles come out a little smaller, angles are rounded.

The end of cut requires the centerline to go slightly past the end so the tip of the blade finishes the cut.

It seems like everyone talks about drag knife compensation, but it is never quite complete. It is a complex thing. However, I have an old Graphtec vinyl cutter, since died, that did all of this in firmware. I found out accidentally that it can successfully cut out Times New Roman 12pt type. So it is doable, that plotter is 20 years old and I’d still be using it if it hadn’t died.