Over-Retraction

[jds25650]

1-2 times per layer, my extruder will "over-retract" during a move. When the move completes and begins extruding again, plastic will not leave the nozzle for around 5 seconds. This leaves gaps in the infill and sometimes the perimeter. When it happens, it tends to happen at the same location on each layer throughout the build. This does not occur between layers, but most frequently while printing infill.

With the exception of these 1-2 over-retractions on each layer, all other retraction operations seem to be working just fine. These are my settings:
Retraction Distance: 2mm
Retraction Speed: 40mm/sec.
Z-lift: 0.5mm

When I print the same part using Slic3r, this problem does not occur.

In the picture you can see in the green material a section where the -45 degree infill was not printed because the extruder "over-retracted" just before getting there. This happened in the same spot on every layer that printed -45 degree (+45 degree worked fine). You can also see spots in the yellow material where this also occurred.

Anyone else run into this problem? Any fixes or recommendations? Thanks in advance.

[JoeJ]

I haven't seen this before with my dual color prints. Can you post a factory file?

[jimc]

i have gotten something similar but not that bad. usually the start of my new line is thin or inconsistent for 5-10 mm then extrusion is fine. for me if my start points are in a row it causes a hole in my print. i haven't quite nailed this problem down yet as its somewhat intermittent. it seems to me that its retracting but at the start of the new line its not returning the filament to where it was before printing again. it might just be coincidence but when i get this i will take my saved profile, trash it then load the default built-in profile for my printer so everything is fresh then plug in the same settings as my trashed profile. i will save that one and print with it. when i do this the problem disappears. its very odd. its as though the profile gets corrupted somehow. again this could all just be coincidence. i havent nailed down anything as of yet so i dont want to say yeah this is your problem. its just something to try. on the mechanical side check that nothing is loose on the filament drive system. this would be a symptom of a loose drive gear, etc.

[DarthRevan]

Can I get a look at your factory file for this?

[inhouse]

Hey! I have got the same problem!

When the extruder moves to the starting point of new a layer, the pla does not extrude for 5 to 10 mm leaving gaps in my prints.
So I started to fiddle with retraction settings and extra restart distance by creating different processes that print 5mm high and then the next process starts with slightly different settings. this way I hoped to find the optimum settings.

The best result was unchecking retraction, but still not 100% okay...
As soon as I checked Retraction in the Ooze control section the gaps appeared, even if the retraction distance was set to 0!
I also played with the extra restart distance by setting it from 0 to 10mm. Strangely it as no effect at all ! while I would expect massive zits.....

I am beginning to think there is a little bug the software (I have version 2.2.2)

[inhouse]

O, sorry, Ill take that back..... It not the program, its the idiot behind the computer setting up the left extruder whilst printing with the right extruder....