Issues printing with Printcore AA 0.8 : Strange Elephant Foot

[V3DPrinting 11]

Hi to all

 

I am trying to print with a 0,8 mm nozzle on my S5, using Cura 4,0.

 

I have used the printcore AA 0,8 profile and printed a calibration cube in PLA, 200 microns resolution

 

I have done some tuning on the temps (nozzle and bed) and material flow, but whatever I set, I still have an elephant foot on all the solid infill layers.

 

So the 5 first layers are consistently at 30,5 mm for a cube of 30 mm side, for the rest of the layers I have a 30 mm +/- 0,05 cube.

 

See picture

 

I forgot to mention that printing with a 0,6 nozzle with a profile derived from the AA 0.4 works fine, no elephant foot at all.

And yes, I am using 3D Solex Hardcores, so I am able to swap nozzles.

 

Also I have noticed an excess of material on the top layers 

 

Has anyone a clue ?

 

Thanks for your feedback

David

[burtoogle 513]

Hi @V3DPrinting, please save the project (File -> Save) and attach the resulting .3mf file to this thread. Thanks.

[V3DPrinting 11]

Here it is !

Thanks for your expertise.

UMS5_Cube plein test.3mf

[burtoogle 513]

Thanks for the file, I sliced it and looked at the gcode and, so far, can't see anything obviously wrong. It simply looks like over-extrusion. Have you checked the filament diameter?

[V3DPrinting 11]

Thanks for the feedback

 

Yes I've checked the filament diameter and it was the right one.

I have also played with the flow rate, dropping it to 90%, but with no success.

 

BTW, the very same filament (same spool, same diameter, 100% flow rate as it's PLA) on the same printer, with the same printhead, but a 0.6 nozzle printing the same part does not create the "elephant foot". I have just swapped the nozzle on my 3d Solex Hardcore.

 

So I believe there is something not properly handled in Cura on the solid infill feature.

[V3DPrinting 11]

UP !

 

I still have the issue with the bottom layers being oversized using a 0.8 mm nozzle.

As there is no issues printing the same part with a 0.6 mm nozzle it may be related to the slicer.

I need to print a big flat part in many chunks and a 0.8mm nozzle would save me a lot of time.

Has anyone a workaround ?

Thanks in advance 

[burtoogle 513]

Hi @V3DPrinting, I'm sorry I don't have any experience using a 0.8 nozzle so I'm just guessing but have you tried using wider lines. Personally, I use 0.5mm wide lines with a 0.4mm nozzle and get really good results so I'm wondering what will happen if you try using 1mm wide lines with your 0.8mm nozzle? At least for the infill if not the walls as well?

[burtoogle 513]

3 minutes ago, smartavionics said:

At least for the infill if not the walls as well?

 

I meant skins, not infill although using wider lines for the infill would probably save time.

[V3DPrinting 11]

HI @smartavionics

 

Using wider lines for the infill doesn't save any time, just more material and weight on the print.

 

And yes I have used wider lines : 0,75mm line width for a 0,8 mm nozzle. I've also made a test with a 0,8 mm line width, but it doesn't change the behavior.

I may have a go on your suggestion for a 1,00 line width with the 0,8 mm nozzle, but it will increase the pressure in the nozzle so retraction and coasting tuning might be a bit more tricky. Generally, I am setting a lower line width than the nozzle size for these reasons.

 

I think there is an issue in the line width calculation / parametrization for the skin and bottom layers.

 

[burtoogle 513]

25 minutes ago, V3DPrinting said:

I think there is an issue in the line width calculation / parametrization for the skin and bottom layers.

 

I checked the extrusion rate when you posted your original message and it looked OK but I will check again to see that the extrusion rate is what I would expect. I'll get back to you on that.

[burtoogle 513]

I checked the extrusion rate and line spacing of the skin lines and they agree with what I would expect given the settings you are using.

[V3DPrinting 11]

16 hours ago, smartavionics said:

I checked the extrusion rate and line spacing of the skin lines and they agree with what I would expect given the settings you are using.

 

OK thanks a lot.

 

So I shouldn't have that issue.

Again, printing with a 0,6 mm nozzle with a 0,55 line width on the same printer / hardcore  with the same spool / material flow / profile (except line width) /  part doesn't create to a larger part on the skin layers.

[V3DPrinting 11]

HI @smartavionics

 

I have done some more testing, as in my customer project I need to make some text insertions into a board. As I don't want to file / sand every letter in order to fit the board, I am trying to get rid of the "elephant foot".

 

First I confirm it is not a classical elephant foot, but the skin layers being larger than the walls + infill layers.

 

Second, I have the issue also printing with a 0,6 mm nozzle. I have double checked the filament diameter and flow rate.

In fact the filament is 2,82 mm for 2,84 mm diameter set in Cura, so the real flow rate is 99%.

 

Third, the issue is on small parts, not on larger ones. See picture : I have printed both parts on the same print job.

On the larger one, I don't have any elephant foot, only a first layer a bit too squished and not fully compensated by the -0,3mm first layer horizontal expansion.

 

 

But on the letter, which is only 25 mm wide, I do have the issue with the skin layers.

 

 

I am currently printing a calibration cube in order to have a precise measurement of the "elephant foot" with a 0.6 mm nozzle.

 

David

UMS5_Test dimensionnel.3mf

Edited April 9, 2019 by V3DPrinting

[V3DPrinting 11]

I have printed a 30 mm calibration cube with the same settings as in the cura project.

the wall and infill layers + top skin layers measure 30,04 mm, but the bottom skin with the "elephant foot" is 30,58 mm.

 

The issue is only on the 5 bottom skin layers, as my settings were 5 bottom layers, after that, the layers tend progressively to reduce to the target size.

 

Given the fact the line width has been set to 0,55mm, there is nearly a full line width added to the bottom skin layers.

 

[V3DPrinting 11]

Just to confirm that it is not a standard elephant foot, but a slicer issue, I have printed a calibration cube with a 2 mm bottom layer thickness.

 

And the issue is on 2 mm height from the build plate ....

UMS5_Cube plein test.3mf

[burtoogle 513]

Hello @V3DPrinting, I printed the bottom of the E model using Tough PLA with a  CC 0.6mm nozzle on an S5 and it doesn't show any signs of bulging at the bottom. I am now printing the bottom of the cube and see how that comes out...

The bottom of the cube is a little wider than the layers above, the difference is about 0.1mm but it's quite hard to detect by eye. Nothing like your example above.

I wonder whether the problem is that your extruder is not calibrated correctly?

 

I have tried to upload a photo here but the forum keeps giving an error on the upload.

 

[burtoogle 513]

 

I reduced the size of the photo (was less than 3M so I don't know what the problem was), it shows the bottom of the cube, you can see a very slight bump where the bottom skin layers are but nowhere near as bad as you show above. This was the worst side, the other sides were better.

 

[V3DPrinting 11]

@smartavionics

 

Indeed it is way better than my prints.

 

Maybe a calibration issue

As far as I know, e steps are an average value, part of the firmware (I have QR3,0 Bondtech extruders on UM3E, so I have to tweak the FW at each upgrade).

But is there an easy way to calibrate it and set it on the S5?

Usually we have to send an extrude command of x mm of filament, then measure the real length of filament that have been through.

Tweaking the FW should be close to the UM3 procedure.

 

Other option is : the extruder is dirty ... I'll have a look tomorrow when my print job has completed.

[V3DPrinting 11]

18 hours ago, smartavionics said:

I wonder whether the problem is that your extruder is not calibrated correctly?

 

 

I have cleaned my extruder, but it was pretty clean already. Nearly no deposits on the knurled wheel.

 

Yesterday night, I have printed a big flat part (300 * 190 * 10 mm), using the same settings as the last posted for the calibration cube.

No bulging nor elephant foot at all. I am still using the same spool.

 

 

I am not convinced it is an extrusion issue.

Though I must admit your prints were really good.

 

I will try to use the CC printcore setting on a calibration cube....

 

[burtoogle 513]

OK, good luck!

 

[V3DPrinting 11]

I have done some more testing on a calibration cube.

 

First I have printed a cube using the CC 0.6 profile instead of an AA 0.4 with modified line width.

 

 

The result is a bit better after tuning the print temp a bit, as speeds are much lower 45 mm/s default speed instead of 70 mm/s in the AA profile.

There is a pretty standard elephant foot at first glance.

Not as good as the prints done by @smartavionics, but better.

 

Then I have printed another cube with the AA profile, with 0,55 line width, to match the 0,6 nozzle, and same speeds as in the CC 0,6 profile.

So the two profiles were the same regarding line width, temperatures, speeds and of course shell and infill.

 

The cube now show a bulge as in the first attempts.

 

So there is something to do with the parameters and the slicer maybe. Are all the features of the CC or AA profile editable in Cura ?

 

Thanks for the feedback

David

[Mardesigns 0]

I am experiencing the same issue, where the number of bottom or top layers you set in cura 4.0 get wider. Even without printing your part you can see this in the preview. Still can't find a solution for it.

[V3DPrinting 11]

Indeed, very close to the print I get. Except the top layers seems to be fine on my prints.