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Posted · Kevin Jones

I've had a U3 for some time, and recently purchased an S5. I'm having a strange issue with Cura 4.1 where parts that print great on the U3 will not print on the S5, and it seems to be a Cura issue. I'm using a variety of materials for the parts (PLA, TPLA, CPE, ABS, PC, etc), but all use the breakaway support material. If I slice a part for the U3, the areas that have support material get a solid floor on the first layer before starting to build up the hollow support structure on the layers above. Slicing the same part for the S5, it always skips the support material on the first layer. On the second layer it starts adding in the hollow support structure, but there is nothing for it to stick to, so it fails miserably. Is this due to a parameter set wrong on my end?

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Posted · Kevin Jones

Please save your Cura project as 3mf file (project file) and upload it here to the forum. Then we can check what's wrong.

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Posted · Kevin Jones

Confirmed this behaviour in version 4.1 for the UM5 file at least.

I also tried to slice it in the 4.2-BETA (I remember something we changed for a bugfix) which _does_ seem to have the first layer support ūüôā

 

... so, it seems unlikely the problem was on your end!

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Posted · Kevin Jones

Thanks for the feedback. Is there a known remedy, or is the S5 just not usable with breakaway support at the moment?

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Posted · Kevin Jones

Unfortunately - no joy with 4.2 beta. It partially fixes the slice issue. There now is support material on the first layer, but in some areas it builds a complete floor, and in other places it tries to build a very sparse structure right on the build plate. The sparse structure won't stick, and the part fails. I'm not sure if this would be considered a Cura issue or a printer issue though. The same part sliced by Cura 4.1 for the U3 gets a full floor anywhere the support material touches the build plate. On 4.2 Beta, however, the support is the same as for the S5. I haven't yet tried a print on the U3 with the weaker support first layer.

 

At this point, I'm seriously regretting the S5 purchase. The U3 has been bomb proof, but I have yet to get any decent prints on the S5. I seem to have trouble getting the breakaway material to feed properly most of the time. It comes out looking kind of burnt, and clumps up. It never sticks in the support tower.

 

I've attached files for the u3 from Cura 4.1 and for the S5 from 4.2 Beta. Any suggestions on how to get the S5 functioning properly would be greatly appreciated.

UM3_Test2.3mf UMS5_Test2.3mf

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Posted (edited) · Kevin Jones

I'm not quite sure what you mean by sparse structure. Could you show some pictures of it? I've sliced both your projects with the latest Cura and i seem to get a pretty good first layer.

Other than that, I'd recommend using build plate adhesion. That should ensure that your flow is up and running before the actual print starts.
UM3:

UM3FirstLayer.png

S5:

S5FirstLayer.png

Edited by nallath
Added labels to clarify which image is of what printer.

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Posted · Kevin Jones

Very strange. Here's what I get - first on the UM3 with Cura 4.1.0, and second on the UMS5 with Cura 4.2.0 Beta. I included a snapshot of the Cura version info in case you are using a different version.

1505128542_UM3Test2Cura4.1.0.thumb.jpg.976a7ac91b98a22f8beab3d3a5bea1cf.jpg

2098208571_UMS5Test2FirstLayer.thumb.jpg.219396e4f6357be5ec1d75f6e1e1148b.jpg

1506238043_CURA4.2.0Beta.thumb.jpg.1285984d4b3dd6d27e1a110d7ca78617.jpg

 

I've tried playing with the stick-on adhesion sheets, but the material sticks to them so well that I can't get my parts off of them. I end up tearing up the adhesion sheet, and some of it remains on my part. Maybe if I used a raft under the part?

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Posted (edited) · Kevin Jones

Quick update - I was just playing around with options in Cura, and if I select "skirt" for Build Plate Adhesion, it adds the full floor on both support areas. A brim using the breakaway material looks even better. I'll try one of those tonight, but it's an 18 hour print, so I won't know for a while. Actually, I'll know early if it fails.

 

Second update: it seems to be doing well now with a brim around the part with breakaway material, however, I just noticed that it wasn't producing a prime ball when starting a print. On the brim, the outer few layers are broken up or missing while it primed the nozzle. I just looked in Cura, and prime ball for the build plate adhesion was disabled (I didn't know that was even an option until now). Seems like default "on" would be a smarter option.

 

Third update: Now I'm really confused. Now that I have enabled prime blob, I'm getting a floor on the support area that looks the same as on the U3 - and that's with the S5. Even stranger, if I now uncheck the prime blob box, it still creates a full floor, in fact, i cannot find a way to get Cura 4.1.0 to fail. If you look back at the beginning of the thread, at that time it skipped the first layer altogether. Now, reopening the test file I posted here a few days ago, 4.1.0 slices correctly, and I cannot figure out why, or rather, why was it slicing incorrectly before?

 

4th update: Even more peculiar - I accidentally had loaded the .3mf file generated by Cura 4.2.0 Beta into 4.1.0, and 4.1.0 now slices that file exactly right - if it is a .3mf file generated in 4.2.0 Beta. However, loading that .3mf file back into Cura 4.2.0 Beta, it still fails to generate the first layer of support correctly. It appears to build the first layer exactly the way the second layer should look. There is also now some issue, perhaps due to having both copies of Cura loaded on the same machine, that has partially wrecked 4.1.0. As mentioned,  the .3mf file loads and slices fine, however, if i load the STL file from scratch, now slicing stalls out half way through, unless I turn brim on. Perhaps an incompatibility in a shared parameter file or something?

Edited by jones007
new intel

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Posted · Kevin Jones

I just loaded the official release of Cura 4.2.0, and it looks like the problems mentioned above still exist. In summary, here's the issues that seem problematic:

 

1). By default, prime blob under build plate adhesion is disabled, but my experience has been that this will wreck a build unless brim is turned on with the support material selected for the brim. Wi9thout this, the first layer of support will be broken up or missing, and if that happens, all subsequent layers of support will also fail.

 

2). Without skirt or brim enabled, the first layer of breakaway support is actually what is expected for layer 2 (compared to what 4.1.0 produced for the U3). The support structure on the build plate is sparse, and may fail, particularly if prime blob is disabled. the workaround is to enable brim with the support material.

 

3). In 4.2.0 Beta, I only experienced these issues on the S5, but now they seem to also exist on the U3. I suppose it's preferable to be consistent across different printers.

 

Now that I've actually been able to get prints made on the S5 with breakaway support material working correctly, it does produce superior parts to the U3. The surface finish is notably better. Not sure if this is merely because the printer is new, and the U3 has been in use for a year or so. The part in question has very slightly off-axis faces, and on the U3 there are consistent ripples due to stepper-motor advance I guess. On the S5 prints, this sort of defect is undetectable.

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Posted · Kevin Jones

I was still on an older version of the Engine. I'm also getting the same initial situation as you now.

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Posted · Kevin Jones

I'm getting pretty good results now if I use a brim made of the breakaway material. It takes a few minutes longer than what was previously done in 4.1.0 for the UM3, but at least now it seems consistent across the UM3 and UMS5. For sure I would advise turning on prime-blob in the adhesion settings. If you're printing with a brim, then you'll probably be OK, but if not your support structure will likely fail.

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Posted · Kevin Jones

I just aborted a job on the S5, and during the abort process it retracted the material about 8 or 10 inches. I thought the machine had locked up during abort, as the print nozzle remained stationary on the build for a very long time. I had to look closely to see that it was retracting material for 20 or 30 seconds. Unsure if this is a Cura or printer issue, but I've never seen it do that before.

 

I've also noticed that with "prime blob" enabled, it only creates a prime blob for material 1, never material 2. As stated above, if it doesn't create a prime ball, and if you are not using a brim made from material 2, the print will likely fail, as some or most of the first layer will be missing while the head gets primed.

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Posted · Kevin Jones
12 minutes ago, jones007 said:

it only creates a prime blob for material 1, never material 2

 

The "Enable Prime Blob" setting is per print core, so you have (or can) enable it for each extruder.

 

Personally I have no problems with a disabled prime blob. I was surprised when I bought the S5 because I was used to get a prime blob from the UM3, but per default it is disabled for the S5. But I don't miss anything and had never issues with the extrusion. I also don't use a brim, only for very rare objects, but I always use a skirt which is enough for me to prime to get a good first layer. 

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Posted (edited) · Kevin Jones

Hummm, so far I've only found a single prime-blob switch. Guess I better look again.

 

I've had many failed prints when prime blob was not enabled for material 2 (breakaway support material). It likes to use a sparse structure on the 1st layer, and if it's not primed and the support area is smallish, there may not be any material at all on the 1st layer. However, if I enable a brim using material 2 then it will prime itself on the outer layer or two of the brim, and this works well - it just requires the use of a brim, which is a bit time consuming.

 

Edit: OK, I see now that the enable prime blob check-box is per-material, even though it's in the adhesion section, with a selection for adhesion material right below it. Hopefully that helps when a brim is not used.

Edited by jones007

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