Happy to update (click to see the GIF):

Printing settings:

• Polymaker ASA @240°c
• Bed at 75°c
• Chamber still heated up to ~50°c (It's passively heated by the giant bed, not much I can do to reduce it)
• Fan at 15% for the entire print, except the first 4 layers

Results:

• Perfectly straight pulley teeth
• Slight deformation on the bottom pulley wall (touching the bed), I think I need to enable cooling there as well, just a bit.

I would like to thank everyone here for your help, it's been amazingly helpful to have so many experienced people chime in and help me improve my printer and my my understanding.

Though the main culprit turned out to be simply a overly hot print bed, I also improved the way I calibrate my printer and removed a different error I have had for years.

Special shoutout to @Norder and @alankilian! Thanks so much!

Pretty sure this isn't the correct place, but didn't know what is.
What I did:

• connect NPN capacitive sensor to z.probe-in
• in configurator I selected z.probe-in as the signal pin
• in the endstop tab, I selected "switch" as the z probe type

Issues:

• selecting "switch" type shows you information that says the probe must be connected to the e0 stop pin
• there is no way to select the e0 pin in the i/o mapping tab
• the output from the configurator was:

M558 P4 C"zprobe.in" H5 F120 T6000

• while the expected output is

M558 P5 C"zprobe.in" H5 F120 T6000

probing did not work with the "p4" option

I very much enjoy the rich and high-quality eco-system that has sprung up around duet, and would like to contribute, if only by bug reports for now. please let me know if this is indeed a bug, and if there is a better place to post it.

Thanks!

Embarrassed / Happy to say that I found a loose connection deep in the mines of moria electronics bay.

Below is the result of wiggling that cable... That cable is very much static during the print, but I guess the vibrations/heat expansion was enough to cause issues?

Lesson of the day: don't use bare wire in screw terminals! (not even "just temporarily to see if it works!")

Thanks all for bearing with me during my somewhat crazy tangents.

Used fallback procedure 1 and all is good.

And yes, it looks like the issue was that I had multiple tabs open....

Thanks @Phaedrux and @chrishamm

@alankilian said in Mushrooming print - What could cause this?:

@leav

Is there any way you could post your STL files (And GCODE for comparison?)

I'd love to try printing this on my Delta to see if there's anything in the model or sliced code that's causing this.

Shoot, I meant to do this with the previous post.
Here is a link to a zip with the two STL files and the SuperSlicer 3mf project (not sure if it's compatible with prusa slicer or other versions). Please let me know what you find.

@engikeneer said in Mushrooming print - What could cause this?:

@leav could it simply be shrinkage/warping?

It looks like the faster layers without solid infil (I.e. the ones that are laid down faster) are just contracting, but the slower layers are maintaining size better.

I'd try a different reel/brand of filament, or a different material

Could very well be. The green material was eSun ABS+, and I printed these black items with Polymaker ASA (same exact gcode).

The deformation is noticeably smaller, leading me to believe plastic shrinkage may be the main mechanism here.
My printing temps:

• Extruder 250°c
• Bed 110°c
• Chamber (passively heated by 2000w bed heater) ~40-50°c (rises during the print)

@norder said in Mushrooming print - What could cause this?:

At first glance it looks like over-extrusion or wrong Z-axis stepps.
The retract doesn't seem to be there either, if you look at the blobs on the skirt and where you move from the skirt to the first layer of the component, the filament runs through without interruption.

Thanks for calling attention to that. I have a super long bowden tube (>1000mm), and retraction is currently set to only 8mm. I think it's very likely it needs to be much larger to account for the extra length of the filament snaking around in the capricorn tube.

Regarding your calibration suggestions, I am jotting down a list here:

• Check drive item tightness (including pulley set screws in all 4 steppers)
• measure axis travel (all 4 steppers)
• Bed level sensor repeatability test
• Check flatness of travel to bed after mesh probing using an indicator that clips on the effector
• Calibrate flow from scratch (filament diameter + flow calibration print)
• Optimal printing temperature test (temperature tower?)

Will report back the results

@o_lampe said in Mushrooming print - What could cause this?:

How about the rod-distance? The effector looks like the magnets are arranged in a regular pattern (more or less)
It seems easy to match the wrong pair of magnets, which would lead to non-parallel rods.

You are correct that it is easy to get a mismatch pair, but in this case it is correct - Thanks!

@norder said in Mushrooming print - What could cause this?:

Did you use the printer to print the red fan-duct that you can see in the photo here ?

Yes

@norder said in Mushrooming print - What could cause this?:

This effect can also be seen there, that the outer wall collapses inwards.
But it seems to be worse on the left side than on the right !?

Good eye, I didn't catch that!

@norder said in Mushrooming print - What could cause this?:

Print a 100mm high cylinder (or even higher) in vase mode and show us the result.
It is best to do this in different places on the print bed one after the other.
For example, as close as possible to each of the three Z-axes and once in the middle.
Just to make it clear where this effect occurs.

In progress now, will update soon, including results of the above tests.

I would like to say thanks to everyone pitching in to try and figure it out, much appreciated!

Happy to report that:

• Changing to 3-parameter calibration removed almost all of the waviness
• Reducing extrusion temp from 250°c to 230°c eliminated the warping near the edge in test parts
• I did indeed find that the socket was coming loose at the edge of the print area as @o_lampe suspected (though I estimate that it was not an issue in the original pulley parts. [Video 1] and [[Video 2](Video 2)], "fixed" by removing excess grease (may redesign the sockets one day)

Original thin wall cylinder (spiral vase)

Same part printed after the fixes 1 & 2 above (the printing gap is due to the socket pulling out, fixed mid print)

Now printing the pulleys again...

@norder said in Mushrooming print - What could cause this?:

@leav
It looks like your component cooler is a hot air gun. Try it with a very easy to print PLA.

If that then looks good, you know that you have to work on the settings of the ASA, but the printer is OK.

You don't know the half of it. Here's a macro shot of the pulley teeth printed with the part "cooler" on, the shrinking is even worse.

Now printing 3 perimeters @ 42% infill in ASA, but I'll bust out my first ever roll of PLA after that.

@alankilian said in Mushrooming print - What could cause this?:

@leav said in Mushrooming print - What could cause this?:

Pulleys do not seem impressed with all the improvements.

Have you tried reslicing with only 3 perimeter walls and 50% infill like I did?

I got them to print prefectly when I made that change even though they printed distorted with completely-filled with perimeter walls like yours.

Doing that now, will update (I went for 18% infill).

@alankilian said in Mushrooming print - What could cause this?:

Also, can you please post the GCODE for just one pulley centered on the bed?

Here you go - This includes a single thick-walled pulley plus a 3-perimeter 18% infill version which I am now printing.

• IR Thermometer was pointed at the black FR4/G10 sheet (not the glass)
• At room temp, the readings are:

 Bed: 26.0°c
Hotend: 24.4°c
Chamber: 26.3°c
Multimeter probe on bed: 28°c

I suspected that my bed thermistor position was not giving a good reading, it was not exactly in the most sensible location.

Here you can see the temperature probe location (under the glass) and the multimeter's probe (I found it) placed on the bed in the center.

I later moved the bed probe (the one the printer uses) to the center of the bed and measured again (in the photo you see it on top of the glass, that's just to show where I placed it, in reality it is under the glass):

The results are quite dramatic:

• In both cases bed temp target is 100°c, and in both cases that temp is maintained on the thermistor very well (blue and yellow lines, blue is barely visible).
• The red line shows that when the probe was not in the correct location, the actual temperature in the center of the bed was much higher and reached ~130°c
• The green line shows that when the probe is placed in the center of the bed, the top of the bed reaches ~77°c
• This is both a large change between the two temperature measurements (~60°c) and in both cases a large error between the value that the controller sees and the actual temperature on top of the bed. I'll have to see how I can address this, possibly a different temperature probe location.
• To be clear, this means that when I thought my print bed temp was 110°c, it was closer to ~140°c, which could explain a few things.

@norder said in Mushrooming print - What could cause this?:

It would be great if you could send one last photo.
Maybe even a cog with the problem and a current cog next to it.
I would be interested in the end result, because the GIF doesn't show how well the print has become.
The top should also be visible.
Thanks !

Thanks for all the tips, I'll definitely give them a try to see if I can improve my accuracy even more (or see how far off I am...)

First the side view (best I could do without a telecentric lens):

This shows the bottom cavity where the plastic collapsed into:

The next one is a GIF:

@o_lampe said in Mushrooming print - What could cause this?:

@leav
It still puzzles me, why it was able to collaps at 100% infill? But I'm glad you found a solution.

The part designhas a central cavity, that gave the plastic a place to collapse into, that's my explanation for "where did the plastic go?".

@hackinistrator said in Mushrooming print - What could cause this?:

that's strange .
i have both esun ABS+ and polymaker ASA.
i use much higher bed temp , around 120-130c and never had this effect .
maybe your bed temp readings are way off .

Definitely could be. I double checked with an IR thermometer and got ~5°c off the printer's reading (which is good for an unknown emissivity, I'd say...). Can't find my multimeter's thermocouple at the moment but I will double check it.
However I think there is a possibility that the readings are accurate and the cause for the different behavior might be:

• High temperature inside the chamber (4 of the 6 walls are double aluminum panels with an air gap between them for better insulation, and the remaining doors are thick glass panels)
• Reflective aluminum walls bouncing the IR radiation from the oversized bed back to part to be absorbed.

Happy to update (click to see the GIF):

Printing settings:

• Polymaker ASA @240°c
• Bed at 75°c
• Chamber still heated up to ~50°c (It's passively heated by the giant bed, not much I can do to reduce it)
• Fan at 15% for the entire print, except the first 4 layers

Results:

• Perfectly straight pulley teeth
• Slight deformation on the bottom pulley wall (touching the bed), I think I need to enable cooling there as well, just a bit.

I would like to thank everyone here for your help, it's been amazingly helpful to have so many experienced people chime in and help me improve my printer and my my understanding.

Though the main culprit turned out to be simply a overly hot print bed, I also improved the way I calibrate my printer and removed a different error I have had for years.

Special shoutout to @Norder and @alankilian! Thanks so much!

@norder said in Mushrooming print - What could cause this?:

I would like to see a video of the print.

A picture is worth a thousand words, but a GIF can hold a thousand pictures.

Since this happened with two different brands, I think there must be something wrong with my temperature settings?

• ABS from eSun and ASA from Polymaker
• Happened both @ 230°c and 250°c
• Bed @ 110°c
• Chamber temp reaches ~50°c and stabilizes there

Those seem pretty standard settings from what I've seen around. Maybe my temperature calibrations are off?

@norder said in Mushrooming print - What could cause this?:

@leav
It looks like your component cooler is a hot air gun. Try it with a very easy to print PLA.

If that then looks good, you know that you have to work on the settings of the ASA, but the printer is OK.

You don't know the half of it. Here's a macro shot of the pulley teeth printed with the part "cooler" on, the shrinking is even worse.

Now printing 3 perimeters @ 42% infill in ASA, but I'll bust out my first ever roll of PLA after that.

@alankilian said in Mushrooming print - What could cause this?:

@leav said in Mushrooming print - What could cause this?:

Pulleys do not seem impressed with all the improvements.

Have you tried reslicing with only 3 perimeter walls and 50% infill like I did?

I got them to print prefectly when I made that change even though they printed distorted with completely-filled with perimeter walls like yours.

Doing that now, will update (I went for 18% infill).

@alankilian said in Mushrooming print - What could cause this?:

Also, can you please post the GCODE for just one pulley centered on the bed?

Here you go - This includes a single thick-walled pulley plus a 3-perimeter 18% infill version which I am now printing.

Pulleys do not seem impressed with all the improvements.
Now trying with part cooling fan on at 50% (even though this is ASA).

Happy to report that:

• Changing to 3-parameter calibration removed almost all of the waviness
• Reducing extrusion temp from 250°c to 230°c eliminated the warping near the edge in test parts
• I did indeed find that the socket was coming loose at the edge of the print area as @o_lampe suspected (though I estimate that it was not an issue in the original pulley parts. [Video 1] and [[Video 2](Video 2)], "fixed" by removing excess grease (may redesign the sockets one day)

Original thin wall cylinder (spiral vase)

Same part printed after the fixes 1 & 2 above (the printing gap is due to the socket pulling out, fixed mid print)

Now printing the pulleys again...

• 3 drive motors tested and all good
• 3 axis travel tested, all good
• Z probe repeatability: 0.065mm and 0.061mm (two different tests, 10 probes each in center)
• Flatness of travel after mesh - to be tested
• Calibrate flow from scratch - to be done
• Temp calibration TBD

I had the same train of thought as @pjl , and found this sentence in the guides:

Bed should be at right angles to the towers in both X and Y directions

Actually, this isn't essential, because RepRapFirmware can compensate for bed tilt. Unfortunately, auto calibration can't easily distinguish between bed tilt and differences in tower separation. One approach to getting the bed level is to mount it on 3 equal-length spacers attached to the lower horizontal frame. If you are using metal corners, the horizontal frame should be at right angles to the towers. If you do need to make any adjustment, you can stack washers or shims on top of one or two of the spacers.

This is actually NOT the case in my printer: the bed flatness must be calibrated by hand every time you need to access the electronics (see pic1 below) and I always just assumed the mesh probing will take care of it.

Running M665 I get:

M665
Diagonals 511.070:511.070:511.070, delta radius 172.890, homed height 341.889, bed radius 160.0, X 0.399°, Y 1.141°, Z 0.000°

An angle deviation of 1.141° means a position deviation of ~5mm, which is just not possible in my printer (the tower tops and bottoms are held in place by two laser cut sheets).

This confirmed my suspicion that I was wielding the G30 command without understanding its power and limitations.

Steps taken now:

• Bed perpendicular-ed to towers with a carpenter's square (see below, it's what I had...)
• bed.g changed to 4 factor calibration (was 6 factor)

Printing test file now, will update!

@alankilian said in Mushrooming print - What could cause this?:

@leav

Is there any way you could post your STL files (And GCODE for comparison?)

I'd love to try printing this on my Delta to see if there's anything in the model or sliced code that's causing this.

Shoot, I meant to do this with the previous post.
Here is a link to a zip with the two STL files and the SuperSlicer 3mf project (not sure if it's compatible with prusa slicer or other versions). Please let me know what you find.

@engikeneer said in Mushrooming print - What could cause this?:

@leav could it simply be shrinkage/warping?

It looks like the faster layers without solid infil (I.e. the ones that are laid down faster) are just contracting, but the slower layers are maintaining size better.

I'd try a different reel/brand of filament, or a different material

Could very well be. The green material was eSun ABS+, and I printed these black items with Polymaker ASA (same exact gcode).

The deformation is noticeably smaller, leading me to believe plastic shrinkage may be the main mechanism here.
My printing temps:

• Extruder 250°c
• Bed 110°c
• Chamber (passively heated by 2000w bed heater) ~40-50°c (rises during the print)

@norder said in Mushrooming print - What could cause this?:

At first glance it looks like over-extrusion or wrong Z-axis stepps.
The retract doesn't seem to be there either, if you look at the blobs on the skirt and where you move from the skirt to the first layer of the component, the filament runs through without interruption.

Thanks for calling attention to that. I have a super long bowden tube (>1000mm), and retraction is currently set to only 8mm. I think it's very likely it needs to be much larger to account for the extra length of the filament snaking around in the capricorn tube.

Regarding your calibration suggestions, I am jotting down a list here:

• Check drive item tightness (including pulley set screws in all 4 steppers)
• measure axis travel (all 4 steppers)
• Bed level sensor repeatability test
• Check flatness of travel to bed after mesh probing using an indicator that clips on the effector
• Calibrate flow from scratch (filament diameter + flow calibration print)
• Optimal printing temperature test (temperature tower?)

Will report back the results

@o_lampe said in Mushrooming print - What could cause this?:

How about the rod-distance? The effector looks like the magnets are arranged in a regular pattern (more or less)
It seems easy to match the wrong pair of magnets, which would lead to non-parallel rods.

You are correct that it is easy to get a mismatch pair, but in this case it is correct - Thanks!

@norder said in Mushrooming print - What could cause this?:

Did you use the printer to print the red fan-duct that you can see in the photo here ?

Yes

@norder said in Mushrooming print - What could cause this?:

This effect can also be seen there, that the outer wall collapses inwards.
But it seems to be worse on the left side than on the right !?

Good eye, I didn't catch that!

@norder said in Mushrooming print - What could cause this?:

Print a 100mm high cylinder (or even higher) in vase mode and show us the result.
It is best to do this in different places on the print bed one after the other.
For example, as close as possible to each of the three Z-axes and once in the middle.
Just to make it clear where this effect occurs.

In progress now, will update soon, including results of the above tests.

I would like to say thanks to everyone pitching in to try and figure it out, much appreciated!

I hear all your thoughts regarding the magnetic cups, I'll give you my own experience with them:

• They feel retained very well with zero backlash under low loads
• If the nozzle collides with the print in any meaningful way, they disconnect totally and very obviously
• In rare cases I've seen them disconnect and reconnect, but this has always been a prelude to a permanent disconnect as described above
• Of course it is possible that what we're seeing are micro disconnects of some sort, but I have a hard time believing the joints would hold on so reliably under disconnect conditions

I decided I don't understand the issue enough so printed some stuff and I have some more data to chew on...

First I calibrated the extrusion using SuperSlicer's generated test:

I settled on 0.92 extrusion multiplier because the -20% circle looked under extruded, and set out to print the whole set to gather more data:

Honestly, I'm at a loss. I can't imagine any sort of issue that could cause this.

The effect is roughly uniform in Z, and has a radial symmetry in the pulleys, so based on my understanding of Deltas, I feel like this should rule out any geometric issues within the system.

There is a transition in the section in the pulley in this area, see the lower part:

And the upper part:

I'll have to sleep on this. Happy to get any thoughts you have and test any theories put forth.

As this looks like it could be contraction, I guess maybe the next step is to test PLA? (never printed PLA before)