I am considering adding software auto-lift for non-extruding moves to my delta support for Duet electronics. The idea would be to lift the nozzle by about 0.2mm during non-printing moves, to avoid the nozzle touching parts of the print that it moves over.
Some ways I can see of implementing it:
1. Add a quadratic term to the tower height vs. distance function. This would make the nozzle describe a parabola, but is computationally difficult.
2. Add a quadratic term to the square of tower height vs. distance function. This is computationally much easier.
3. Split each non-printing linear move into two separate moves of equal length, and increase the height at the join.
Has this been done before? Is it a good idea, or a waste of time? I see that slic3r has a "Lift Z" option in the filament retraction settings, but I've never tried it. It also has an "Avoid crossing perimeters" option, although I am told that it can make slicing very slow.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].