Undesired "stringing" commands in the gcode

[jep1955 0]

So.  Visualize a square box with a hole in the middle.  When I print the part (Created in CURA), it prints material from the outer square boundary to the inner circle boundary.

 

The head does not lift.

The filament does not retract.

 

I get a lot of this.  I'd rather have it print the outer boundary (box), lift (and pull back the filament), move to the circle, drop, restore filament, and print the to objects isolated from each other.  Z hop and all that kind of stuff does not seem to fix this.  The printer connection seems to be intentional for some reason.

 

I should note that if I print two separate parts it does *not* do this between parts.  Just isolated features on the same part.

[gr5 1,137]

Well the answer is to turn off combing mode off.  This should enable retractions even "inside" the part.

 

First note that your cad model specifies that the space between the box and hole should be solid.  So you might want to change the cad model instead.

 

So the reason you get this string on each layer is because cura doesn't retract.  It's trying to save time since normally people don't mind if there is a little stringing inside their part where no one can see anyway.  When retractions are turned off the nozzle keeps extruding.

 

There are 2 kinds of "non printing" moves: retraction and non-retracting.  They are different shades of blue in the layer view.  Make sure you see the moves change color in layer view to be sure that disabling combing will do what you want.  No need to actually waste another print if I'm wrong about combing.