Does this problem have a name?

[cheuschober 1]

Hi. I just did a major servicing on my S5 (all belts changed, axles realigned, new feeders (fine knurl), etc) and I've been run calibration prints when a new problem evolved and I'm not sure what to call it which makes looking for a solution much harder.

The print here is a califlower. I can't include the STL for reasons that it's not my model to share but this is an XY+Skew calibration tool being printed here at 0.1mm with Ultimaker ABS and the AA0.4 print core. This model has both a top and a bottom chamfer and at both there appears to be some kind of bulging or the walls are collapsing inward a bit. As I said, I'm not sure if this has an official name and/or solution but I'd really appreciate it if someone could point me in the right direction.

 

ultimaker-s5-abs-calibration.curaprofile

[MariMakes 168]

Hey @cheuschober,

 

Your ribbing seems to happen at quite regular intervals. 

Could there be something with your Z spindle? 

[cheuschober 1]

Hi @MariMakes

If the bulging wasn't happening right at the point where the angle of the chamfer hits, I'd be more inclined to investigate that. I The other banding is just some ringing from a rather fast jerk (30mm/s). If it wasn't clear, this isn't the print orientation -- it's flipped on its side 90 deg so I could show the funny bulging along the XY where the chamfers angles meet the walls.

[libertyhouseplans 2]

@cheuschober It's tricky to spot what you mean. Would you mind posting another photo and labelling it with an arrow?

[MariMakes 168]

Oh, if the orientation you see is different, you might be seeing some ringing/ghosting. 

That is often linked to buffer underrun, where you have too many actions in a short amount of time and the printer cannot keep up. You can quickly see that by increasing your resolution settings, which will reduce the number of segments. 

 

Are you up to date with Firmware and Cura versions?
We've made big steps in reducing the buffer underrun with the default settings, but you can only use them if you have a firmware version over 7.0.3 and a cura version over 5.1

 

[cheuschober 1]

On 2/23/2023 at 9:38 AM, libertyhouseplans said:

@cheuschober It's tricky to spot what you mean. Would you mind posting another photo and labelling it with an arrow?

 

Absolutely! Here are two calibration print examples. There's something happening at the top and I'm realizing it really doesn't matter if it's chamfered or not -- something is expanding beyond or pushing the walls out and I cannot seem to narrow the relevant setting in Cura...

 

I also know I've got a bit of elephants foot there which I'll eventually dial in via Initial Layer Horizontal Expansion.

[cheuschober 1]

On 2/27/2023 at 4:15 AM, MariMakes said:

Oh, if the orientation you see is different, you might be seeing some ringing/ghosting. 

That is often linked to buffer underrun, where you have too many actions in a short amount of time and the printer cannot keep up. You can quickly see that by increasing your resolution settings, which will reduce the number of segments. 

 

Are you up to date with Firmware and Cura versions?
We've made big steps in reducing the buffer underrun with the default settings, but you can only use them if you have a firmware version over 7.0.3 and a cura version over 5.1

 

 

 

Hi! Yes. I'm running Cura 5.1 with the latest 8.x firmware. I didn't have this ringing until I changed the belts so I wonder if this is an artifact of what's now a rather rigid system (by comparison). It's pretty consistent on both X&Y.

 

Here's the profile I've been using thus far which was largely based on the default Engineering Fine profile

ultimaker-s5-abs-calibration.curaprofile

[cheuschober 1]

Oh, also, here's a small test model though it obviously shows up on multiple models:

ChamferBulge.obj

[Torgeir 212]

Hi @cheuschober,

 

You must save this object as a project file, if not it is impossible to see if this is caused by any Cura adjustment.

 

 

Also, this object is pretty small, so a better picture may also help.

 

Thanks

 

Torgeir

[cheuschober 1]

Here's a calibration cube that's showing the same effect.

Anywhere there's a bottom or a top, there's bulging that seems to get worse the closer it gets to the top / bottom.

 

This cube measured at Layer 4 or 195 was effectively +0.1mm over layers in the center. While initial layer horizontal expansion can help with elephants foot, it seems like something else is either bulging with top/bottom or the walls are collapsing.

TopSurfaceLip.3mf

[Torgeir 212]

Hi @cheuschober

 

I can see that you're using Cura 5.2.1, witch is great for trying out the new functions on your projects.

 

However, I'll think I would use the last stable old "engine" found in Cura 4.13.1 for calibration of my printer, as this one is proven very accurate over time.

Use standard profiles that's well proven, this will be the better approach for proper calibration.

 

As this new version of Cura can adjust the line width very much and indeed can influence on a lots of parameters.

This will avoid any conflicts between the new software and the calibration of your printer.

 

Good luck

Torgeir

 

[PaulKuiper 5]

Bulging on a top layer can indicate an overextrusion of your machine for this material. Pressure can then build up when printing the dense skin layer and it is released at the edge of skin. 
 

Reduce the “skin flow” setting with 2-3% and check if it improves. 
 

 

[Torgeir 212]

Hi @cheuschober

 

As I've been reading through again, about your issues, -cause I could not find any problem with your settings.

Come to think about the belts you have changed, to low tension can create ringing and stretching to much give to high friction (cause the belt do not match the pulleys teeth).  Sure I'll doubt that the tension is too high.

 

The belts is wider in order to handle the heavier mass of the head and shafts in the "new" series of Ultimaker printers.

So for the ringing, the belt might have a "little" to low tension.

 

So after such a maintenance we'll do some testing to be sure that our printer still is according to its specs.

Finally, there is one other issue to check, -is your nozzle at the proper size?

Nozzles do wear and can be the reason for this issue as it may give a little too high flow when the printer slow down.

 

I'll think it's a good idea trying to reduce the flow as @PaulKuiper suggest.

 

 

 

 

 

[cheuschober 1]

Thanks @PaulKuiper -- that definitely had me along the right track and was consistent with what I was thinking. After about 50-ish calibration prints I think what was happening was a confluence of multiple factors.

The biggest benefit came from upping the build volume temp from the default of 35C to 50C and changing fan speed from 15% to 65%. That had the most dramatic effect on what I suspect was warping due to the top/bottom having so much more plastic than the body and the forces related to that pulling inward.  Moving more air onto the freshly melted plastic and keeping a generally warmer chamber had a dramatic, but not complete, effect.

I then *also* had to dial down the skin flow by a couple % as you suggested to get a clean corner.