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funny lint (Cura 13.12)

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Hello people

I once downloaded this two-part SlipCase in Cura 13:12. There I also increases both parts together and positioned perpendicular to the virtual construction platform. So far so good.

Then I have the G code is generated and stored on the SD Card. At the Cura-basic settings I have changed nothing.

My Ultimaker2 began printing layer by layer in the transition from object to object. Since the objects in the result in each case are very high, the Ultimaker can print them and not one after the other, otherwise it would collide with the already finished object with the linear guides and or the print head at the beginning of the Second Print.

So everything is obviously correct expired and the two objects appear to be a total success.

But the printer has entailed when changing from object to object during the layered structure funny lint, which can be removed easily determined.

So the whole thing requires some post-processing, but maybe I can in Cura what optimize now and I'm looking for the appropriate edit option ... Retraction?

One of the two objects was up slightly closed, although both are supposed to be open.

Incidentally, I have also problems with some small objects to remove the support material, it has a tight fit.

Does anyone have some helpful tips for me?

The related pics you will find in my User Album in the forum.

Thank you


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Hi Markus... first question... where in germany are you ?

Schone Grusse aus wonderschon Leipzig :wink:

Back to topic... in most prints you will normally get a little lint. small tiny lines of pla traced between jumps from one object to the next. That is normal !

Of course what you can do. to reduce the work after your model is finished is to do exactly what you are talking about... go into the retraction settings in cura and bring up the speed a little and test. also you can increase the retraction distance a little as well... why not setup a very simple test box... then space.. than box as a printable STL...

then increase the settings and try them out on the box test ?

Ian :-)


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Hello Ian

I live in Flensburg (Schleswig-Holstein) near the Danish border.

You a Happy New Year and best wishes.

Regarding the Cura settings I try step by step and look for confirmations for my suspicions. I'm also only since just before Christmas with the Community.

Thank you very much

@ illuminarti

Also of course you a Happy New Year.

I am now a bit confused, because I can change directly on the working device retraction. In the Cura basic settings there is no retraction. And in the Expert settings is a general default, which is probably extremely material dependent. Correctly?


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On the UM2 you can change the amount of retraction that is used when retraction happens. But the decision whether to use retraction or not happens during the slicing process.

In the quickprint settings - (High Quality/Normal/Fast) - I don't think any of them use retraction. At least they didn't last time I checked. I thought that was what you were using - and I would recommend not using them.

Once you go into the full settings mode, then retraction gets set in two different places...

First of all it is either turned on, or off, on the Basic Tab. If it is off there, there won't be any retraction. If it is on, then retraction will be used, depending on the settings in the 'Expert Settings':

Minimum Travel sets a distance threshold. Any move less than this won't have retraction. I generally set this to 1mm - that's means it won't retract when moving between adjacent lines of print, for instance, but will on anything longer.

Minimal Extrusion before Retracting is a safety feature - and specifies the net amount of extrusion after one retraction before another can happen. A small value (0.02) or zero here is fine on a UM2. it is designed to prevent grinding away filament by constantly retracting over the same spot, but it seems not to be much of a problem on the UM2.

'Enable Combing' - when this is on, moves within the same part of a print will try to avoid crossing the edges of the print. So if printing a C shape, and moving from the top right part to the bottom right part, it will curve around the C, staying inside it, rather than jumping across the gap. This is generally a good thing... but, it also disables retraction currently, which means that the head can ooze while moving, leaving the head with too little plastic to resume the print immediately after. So I generally turn that off.

So then, these settings determine when a retraction is requested, and the settings in the printer determine what that retraction is. I generally use 5.5mm at 35mm/s as my in-printer settings.

(On a UM1, all of the above also applies, but there speed and distance is set in the advanced tab, and hard coded into the gcode, rather than being set at print time).

The other thing to do to minimize any oozing is to make sure your travel speed is quite high - I use 250mm/s on my UM2. That will minimize the time that plastic can be oozing from the head during the move, by making the move happen fast. It also makes it more likely that any string of plastic being pulled from the print breaks quickly, rather than extending out.

The settings might need a little bit of tweaking to get good retraction, but generally speaking the UM2 seems to have a much better handle on retraction than the UM1. I generally go with those quite aggressive retraction settings, and if that still causes any stringing (which is rare), I just lower the temp a bit (which should make the plastic less stretchy), and then the speed (which should reduce the pressure in the head, and hence the tendency to leak).


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Oh, thank you for your detailed explanation, I have to swallow this now first ...

What the hell ... The result is in any case already convince enormous. I'm curious if my RepRap printer will be able to follow.

I do not regret my purchase never ... I'd rather sell my car ... and my wife I send on holiday, alone, and for a very very long time ... And I have a feeling it will be much better if I understood the machine and Cura. I'm looking forward to new Cura versions with tons of tuning options ... sob ...

Have you all a nice time.


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I'm glad you're getting good results.... it's a great printer! :-)

However, don't expect Cura to offer lots of tuning options any time soon. The number of options is gradually being reduced rather than expanded. Mostly the defaults are ok, or the behavior is intelligent enough. But, there are time that I wish for more control...

But, Cura was always about making 3D Print slicing approachable and manageable. It began as a front end for Skeinforge which had hundreds (thousands?) of possible settings, and set out to reduce that to a sane number that a normal user could understand.

Then, in the middle of 2013, Daid took the brave step of writing his own slicing engine from scratch - one that is much faster, and still evolving, but already quite capable. It's a great asset to the UM community and company, but I think its fair to say that the direction is always likely to be in the direction of fewer configurable options, rather than more... or at least, extra options are only going to get added when there's a really good reason to do so. :-)


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Uh, that with tons of options I have something fun meant. It's good to find a way for beginners and experts. I also believe it was quite well done.

But great men need toys with lots of buttons and lights, like a helicopter cockpit :smile:

Sorry for that...

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