We need a special Form of Spiral Mode

I print large objects with large nozzles (1mm or 1,2mm). Therefor I use PET-Filament, because it sticks to the printing-bed and does not warp and it keeps stabil under sun.
Printing such fluid Filament with large nozzles leads to specific problems, because large nozzles loose filament in empty travel.
Retraction will not help. If I retract too much air comes into the nozzle, but it keeps loosing filament. Blobs appear if it prints after a travel.

It is no good idea to do fillings with a large nozzle. Only 100% fillings are practicable because the walls of fillings are as thick as the nozzle and press through the perimeters.
If I use fillings, then I draw them myself, like in this case. I import them as an extra object, so Slic3r prints them after the perimeters:


Edited 3 time(s). Last edit at 09/18/2018 07:07PM by ManfredGotthalmseder.

Now let us come back to the Problem:
As soon as an Objekt needs fillings, printing with large nozzles leads to artefacts like shown in the images:
The red arrows show where the Problem comes from: It appears just, when there are these little fillings done. If I delite those fillings (0% filling instead of 100% filling) the print appears perfect. But I need the filling for stability. Slic3r does all the perimeters and afterwards all the fillings. Therefor it travels from one area that has to be filled to the next, and while that travel large nozzles loose filament. That leads to the shown artefacts.




Edited 4 time(s). Last edit at 09/18/2018 07:02PM by ManfredGotthalmseder.

And now the solution:

Prints with large nozzles get perfect, as long as empty travel is not done or reduced to a minimum. So it would be useful to fill every layer in one move without empty travel or two moves if there are two seperate areas to fill. For example the shown shape could be done like this:


I would donate a project that leads to a "no empty travel"-mode! We can also call it "advanced-spiral-mode".
Is there any programmer who wants to work on it?

Edited 4 time(s). Last edit at 09/18/2018 07:10PM by ManfredGotthalmseder.

You'd have to design each part in such way, that there are always even numbers of perimeters. Or the extrusion width has to vary to make it even.
Not the way to go.

Manfred.

Possible a comparable problem dicussed in - (Experimental - GCODE Optimizer)
[reprap.org]

JoRo