Cura 13.11 retract before every layer change

[jimmy 0]

I've noticed something strange with my prints after I switched to Cura 13.11. An retraction/extrusion cycle seems to occur at each layer transition, with very little x-y movement. Sample g-code looks like this:

G1 F2400 X107.97 Y127.04 E214.34222

;LAYER:80

G1 F2400 E209.84222

G0 F9000 X107.85 Y127.55 Z8.20

;TYPE:WALL-INNER

G1 F2400 E214.34222

There is a retract, then a z-level change with slight x/y movement, then re-extrude.

I think the retract cycle is occurring at the beginning at an infill pass.It seems to occur for me with multiple models. This does not occur with Cura version 13.09 pre-release.

Minimum travel and minimum extrusion are set to 0... Combing is enabled.

Any thoughts on a setting I could change to stop this? It isn't a big thing, but on small items the blobbing is noticeable and one wonders whether filament grind-thru will become a problem.

 

[gr5 2,167]

Is retraction visible in layer view? It is shown as a *vertical* short blue line. If so you could experiment and set the minimum travel to .7mm (which is farther than this moved) and see if the line (retraction) goes away.

[jimmy 0]

Hi gr5,

Thanks! Yup, that did it. The retractions do show in the layer view, and they go away with minimum travel set as low as .3mm.

I guess I don't quite understand the intent of the min travel setting... My impression was that this setting regulated behavior based on all head travel between retractions. This part is basically a 11mm dia. cylinder w/ 100% infill, so there should have been more than enough travel between layers to avoid retracts. Ah well... one of those little quirks I suppose.

Thanks for the help!

[Daid 305]

Retraction works like this, if the head needs to move from place A to B without printing, it will do a few checks:

* If the distance between A and B is less then the minimal travel, do nothing, just move there.

* If point A or point B is not 0.6mm within the object boundary, it will move the points inwards and travel to the new point A

* It draws a straight line between point A and B, if there is no intersection with this line and the 0.6mm internal boundary, do nothing, and move straight to B.

* When we do cross a boundary, try to find a path around it. (Called combing)

* If no path can be found that stays in the boundary, retract at the new point A and push back at the new point B.