Problem with 13.10 Cura "Retraction"

[oatfoundryprinting 0]

Hello Ultimakers,

I've recently downloaded 13.10 Cura and have been testing out some prints of mine, and I began to notice a drop in quality of my finished prints. The "drop" in quality is not so much to do with the actual layers of the print, so much as it does with the "moves" and retractions of the print.

I've noticed that my prints sliced with Cura 13.10 often opt to not make a full retractions when moving across my part. As a result, I am left with large strings being pulled across open areas of my print. This leaves lots of excess material that I must cleanup afterwards, even on the most simple of prints. Now, it's not very hard to do this, but I find it vexing that this new version of Cura seems to have it's own sense of when to retract fully, and when to simply move (even though I have specified retractions in the expert settings). Below is an example of these extra drags across the middle of my parts that I feel should be full retractions. In the upper right of the print, these excess drags can be noticed.

http://imgur.com/DX7eiO0

I understand that this is probably done to preserve the filament by reducing retractions, but it's annoying when Cura 13.04 or 13.06.4 result in MUCH better looking prints due to retracting when necessary. Is anyone else noticing this kind of behavior from your machine? Are there extra retractions settings that I can mess with in order to reduce these artifacts?

Many thanks for reading!!

 

[Daid 306]

In the expert settings, there is a "minimal extrusion before retraction", most likely you need to tune this a bit down to get the results you want. It's a setting that sacrifices sometimes quality a bit to reduce the chance of jams.

 

[oatfoundryprinting 0]

Daid,

Thanks for your reply! The "minimal extrusion before retraction" setting is exactly what I looked to to solve this issue. I have the numerical value in this field set to a ridiculously small number, 0.5mm I believe, and yet still I get these massive strings caused by the head deciding to "move" without a retraction. The extruder is not actively pushing filament during these moves, it simply leaks due to the plastic being heated and results in self-ooze.

Watching my prints, I have noticed these types of "moves" occur even after a substantial amount of printing has been completed. That is to say, I am positive that more than 0.5mm of fiament has been extruded since the last retraction, and still the machine refuses to retract before certain moves. What's more confusing is that it seems to be inconsistent. I will notice proper retractions before most moves, but a few hiccups still persist and I am left with additional stringing.

Additionally, I have tried printing identical objects using 13.07 TestSupport Cura, and this version also has the "minimal extrusion before retraction" setting. At the same setting of 0.5mm, I get cleaner prints using 13.07 TEST than I do 13.10. This makes even less sense to me, as it suggests that the problem does not lie within the "minimal extrusion before retraction" setting.

Thoughts?

Thanks again for reading.

 

[oatfoundryprinting 0]

Here is another great example of what I am talking about. New Tapir Fan Shroud v4.9 from Thingiverse. The print has LOTS of excess webbing on the inside of the part.

http://imgur.com/nnBNMtw

 

[3dcase 37]

Hi,

I'm struggling with this retraction thing as well, pretty sure my 13.11 doesn't retract atl al blue lines, even the 50mm long ones and with more than 0.5mm feeded filament.

But why? I don't know jet, still observing what happens.

But on the picture of your fanshroud, It looks to me that 90% of the stringing is because of the steep overhang.

I assume You've printed it with the fan mount facing down. So the inner wall perimeter is not touching the lower layer enough. The shrinking makes it even look worse.

But some of the strings, for sure the ones crossing straight from one side to the other. are strange (Non)retraction things.

 

[Daid 306]

Got some links to the models?

Note, I've tweaked the combing and retraction code quite a bit. It remains a difficult thing to get 100% right, as there are all kinds of tiny details to get right. For example, before I retract, I move inwards a bit. And combing I do not do on the outside boundary, but 1.5 line widths inside the print.

What I do find odd is that the code should comb or retract, but with these lines it does nether of them...

 

[oatfoundryprinting 0]

Daid,

You would want to see the gcode the file was sliced into, or the original .stl?

Also, what is combing exactly?

 

[Daid 306]

The stl files would do.

Combing is staying inside the model during travel moves instead of going in a straight line from A to B

 

[3dcase 37]

I'm working in Cura 13.11, but i guess partly the same problem.

Combing is enabled, retraction is set, min. extr, before retraction =0.0.

Printhead moves while filling the four corners, the shortest way from one to the other corner, without retraction.

That's a little lie, sometimes it retracts but have'nt found exactly when and why?

 

See if I can upload the gcode somewhere. Renaming from .gcode to jpg was a to simply tric :(

 

Edit..

http://3dcase.eu/Zooi/LampPart8.gcode

 

[oatfoundryprinting 0]

Daid,

http://www.thingiverse.com/thing:107413/#files

The V4.9 Shroud (last file) is what I was trying to print. And Thank you for clarifying combing - I have noticed it does that on some moves so that the "drag-behind" is in the internals, but it's not consistent.

 

[gr5 2,228]

That is to say, I am positive that more than 0.5mm of fiament has been extruded since the last retraction, an

 

You could set it to zero maybe?

.5mm of filament at 2.85mm diameter is the equivalent of a 250mm string of filament .1mm high (125mm if .2mm layers). Are you sure you printed more than 250mm since the previous retraction?

 

[3dcase 37]

You could set it to zero maybe?

.5mm of filament at 2.85mm diameter is the equivalent of a 250mm string of filament .1mm high (125mm if .2mm layers). Are you sure you printed more than 250mm since the previous retraction?

 

I'm using 13.11 but setting that value from 0.5mm to 0.0mm makes no difference, using 0.01 neither.

As far as I can see, the 'problem' occurs with/while/after separated (I mean more spots per layer)

infills