Ultimaker 3 not calibrated?

[ATS_DEMUC 0]

Hello.

I've been working with Ultimaker 3 for a bit, managed to get some decent prints, and got some problems with dual extrusion prints.

For that reason, I've performed both bed levelling and XY calibration.

 

After a while, my prints started to get worse and worse. Whenever I use dual extrusion, the layers never align. 

Taking a closer look at the first layer, the second material clearly doesn't have the same " coordinate referential" as the first material (if it's supposed to be two concentric circles, the second one would be off center).

 

The first time it happened, I wasn't paying attention and I've let it print around 20 layers. Even edges of the same material weren't aligned (layer by layer), which means... it dis-aligns whenever it performs a core switch? (all layers were dual-material, but the "outside" of each layer was always the same material).

Whenever I print with 1 material, it prints fine.

 

I performed more XY calibrations after that in-between prints, even asking help for other sets of eyes, but it doesn't solve it.

 

So I'm here to ask you, what do you think it's happening?

 

PS: I don't have pictures to show you because all the print went straight to the bin

Edited May 9, 2022 by ATS_DEMUC
PS

[ATS_DEMUC 0]

Any ideas?

 

I really needed to fix this

[Smithy 1,144]

I have no idea, but have you tried to print just with Print Core 2 ?

 

Maybe @gr5 has some more ideas....

[tomnagel 126]

You say you see that layers of the same material are mis-aligned. So we can rule out the XY offset calibration. 
is this happening for both materials? Or only for 1 material?

A good test print might be 2 separate cylinders, one with each material. 
and pictures help greatly!

[ATS_DEMUC 0]

18 hours ago, tomnagel said:

You say you see that layers of the same material are mis-aligned. So we can rule out the XY offset calibration. 
is this happening for both materials? Or only for 1 material?

A good test print might be 2 separate cylinders, one with each material. 
and pictures help greatly!

 

I tried to do what you said.

 

First print: 2 cylinders, one of each material, printing at the same time, both PLA

Second print: 1 cylinder with 2 materials, both with PLA

Third Print: PVA with PLA support+brim

 

In the third print, it's clear that it is mis-aligned. There should be 2 lines of PVA around the PLA. But it's clear that the PVA is too much to the "left".

The first time I tried it, I had enabled the setting "enable prime blob", but that has some issues, because sometimes it gets dragged to the print. And then I have to pause, to take it out. And so, I thought it dis-aligned when I paused it and resumed it.

There's two pictures because I tried more than once. Actually tried 4 times, always the same output. Always dis-aligned in the same direction. 

 

 

 

 

Now.. why? Well, the only thing that differs is the material.. and the core.

 

But last time, I also had issues with that orange PLA + Ultimaker White tough PLA (so, both AA 0.4). Unfortunately I don't have photos of that.

 

I cannot understand.

[tomnagel 126]

In your previous post, you said you saw layers within 1 material misaligned. 

Have you not been able to reproduce this?

 

About the pictures from your most recent post:

what was you conclusion from your print 1 and 2? All fine? No layer shifts?

 

The pictures with the PVA around the orange object show a non wanted offset. Are you aware that XY offset calibration must be done for all print core combinations separately?

so if you are not satisfied with the alignment, you have to do the XY offset calibration procedure with those cores!

Edited May 13, 2022 by tomnagel

[ATS_DEMUC 0]

15 hours ago, tomnagel said:

In your previous post, you said you saw layers within 1 material misaligned. 

Have you not been able to reproduce this?

 

About the pictures from your most recent post:

what was you conclusion from your print 1 and 2? All fine? No layer shifts?

 

The pictures with the PVA around the orange object show a non wanted offset. Are you aware that XY offset calibration must be done for all print core combinations separately?

so if you are not satisfied with the alignment, you have to do the XY offset calibration procedure with those cores!

 

The first time this happened, I was printing a tough PLA rectangle with orange PLA lettering inside/on top of it. 

 

Then, I changed to BB0.4 and PVA (the focus of my work) and started happening with it aswell. 

 

But yes, the PLA prints worked fine this time, unexpectedly. And no, I couldn't reproduce those issues again. 

 

Maybe I did calibrate it properly with AA0.4, but not with BB0.4?

 

I guess I'll try it on monday! (Unfortunately, it's my work's printer, not personal)

 

 

[ATS_DEMUC 0]

On 5/13/2022 at 6:42 PM, tomnagel said:

The pictures with the PVA around the orange object show a non wanted offset. Are you aware that XY offset calibration must be done for all print core combinations separately?

so if you are not satisfied with the alignment, you have to do the XY offset calibration procedure with those cores!

 

Well, I made another XY offset, with AA and BB cores.

I changed it from around -15 on X, to +16.5. (remember that on -15 the PLA+PLA prints were fine)

 

You wouldn't believe the result of the print, after calibration. Check the attached picture, I cannot believe it.

 

So.. with -15, the print is mis-calibrated to the left. With +16.5 it's mis-calibrated to the right. I'm guessing it should be calibrated if I choose +1 then 🤓 (trying it right now).

 

But then, why on earth is my calibration... mis-calibrated? 

 

 

[ATS_DEMUC 0]

I ran the XY offset calibration again, but this time the most aligned X segments were on +4.

It seems aligned, but it lacks quality on the PVA structures. It doesn't seem that the UM3 is able to print PVA with decent resolution. Which is a whole other problem.

 

Anyways, the Y is constant at -3 from the last 3 calibrations.

 

Why is X fluctuating so much? 

[tomnagel 126]

I have never seen values of -15 or +16. It's hard to say what is causing this.
It seems we need to concentrate on the second print core. The printhead and printcore is designed such that the repositioning accuracy is very high (better than 10mu, more than good enough for what the application requires).

The design is certainly good,  but something is wrong in your system. 

Since you do not see this problem when you place your AA core in slot 2, the problem seems to be in the BB core. You could try to print with another BB core in slot 2. 

 

Another idea: when you lower the right nozzle, and try to manipulate the nozzle in XY direction, how does that feel? Is it firmly positioned? Do you feel play?

 

 

 

 

 

[ATS_DEMUC 0]

1 hour ago, tomnagel said:

I have never seen values of -15 or +16. It's hard to say what is causing this.
It seems we need to concentrate on the second print core. The printhead and printcore is designed such that the repositioning accuracy is very high (better than 10mu, more than good enough for what the application requires).

 

It certainly feels like a problem with the printcore2 or at least the "right" side of the printhead.

 

1 hour ago, tomnagel said:

You could try to print with another BB core in slot 2. 

 

I have more BB cores, but I think they're in worst shape than this one, or at least clogged. We've received this printer from colleagues, and it doesn't feel like they took care of it properly.

 

1 hour ago, tomnagel said:

Another idea: when you lower the right nozzle, and try to manipulate the nozzle in XY direction, how does that feel? Is it firmly positioned? Do you feel play?

 

Not sure what you mean "when you lower". You mean manually move the printhead in the settings, with the printcore 2 selected?

 

Before I advance any further in your suggestions, let me tell you what I've done so far:

 

I've changed printcores from slot to slot. BB to 1, AA to 2.

Performed a XY calibration, and the polarity got inversed. From +4 to -5 on X, from +3 to -3 no Y.

Another interesting thing happened, for the first time the PVA prime blob wasn't dragged in the beginning of the calibration. Which led to the best quality (print-wise) calibration grids I've seen.

 

I tried to print my part (in an updated slice) and got this error message twice: Nozzle Offset Probe Failed

 

EDIT: My mistake, nozzle had a bit of dried filament that was messing up auto-levelling. Gonna try the print

 

Edited May 16, 2022 by ATS_DEMUC
own mistake

[tomnagel 126]

With “lowering” I mean with the mechanical switch on the side of the printhead. When it’s in the lower position, it should be firmly and accurately positioned in all 6 degrees of freedom 

Edited May 16, 2022 by tomnagel

[ATS_DEMUC 0]

5 minutes ago, tomnagel said:

With “lowering” I mean with the mechanical switch on the side of the printhead 

I can't answer this right now, since I changed the slot where it was. But in slot 1 feels normal

 

Well, after changing printcores from slot 1 to 2 and vice-versa, I got the following results (look at the pictures).

The red is supposed to be PVA, the light blue PLA.

During the print, the first millimeter (in height) of PVA was decent. The second millimeter was off-center; and then, the nozzle probably hit it/dragged it and literally pushed it off the table. Got pictures from how it was, and how it got. 

 

It literally dis-aligned during the print. 

 

 

 

[gr5 2,172]

1) With your first post I thought you maybe didn't do the XY calibration right (by the way what were your final values?  Usually they are 0 1 or 2 at the most).  Note that if you swap cores you also have to recalibrate.  The printer stores XY calibration values for every pair of cores in the position when you calibrated.  Each core has a serial number so if you insert a combination it recognizes then it uses the old XY calibration data.

 

Z calibration is not stored  when you change a core because you may have touched one or more of the 3 bed leveling knobs since the last Z calibration it's not valid anyway.

 

2) But with the post above it sounds like you have a completely different issue where the print head is knocking the PVA apart?

 

3) Also your screenshot above seems to show that the C shape is support and the column should be PLA but in the photos above that is backwards - did you swap filaments in addition to the cores?  I don't recommend that unless you reslice as it will be using the wrong temperatures.  Which could explain #2 above.

 

4) Please clarify which issue you want us to tackle first:

A) XY calibration issue between the two cores or

B) Bad alignment part way through a print.

 

[ATS_DEMUC 0]

16 hours ago, gr5 said:

1) With your first post I thought you maybe didn't do the XY calibration right (by the way what were your final values?  Usually they are 0 1 or 2 at the most). 

 

My first calibration with AA on slot 1, and BB on slot 2, X was at -15 (Y=-3). The PVA was mis-calibrated and printing too much to the left.

My second calibration with AA on slot 1, and BB on slot 2, X was at +16.5 (Y=-3). The PVA was mis-calibrated and printing too much to the right.

I then noticed the pattern -> -15 LEFT, +16.5 RIGHT. So I guessed I should put a number in between. But then..

I ran a third calibration with AA on slot 1, and BB on slot 2, and X was at 4 (Y=-3). 

The print seemed calibrated, both filaments (PVA and PLA) were aligned, but it wasn't printing properly. Where we should see two PVA circles (1 filament line each) with scarce infill (space between circles so thin that it can't deposit material uniformly), we could just see a zig-zag circular shape, that had different zig-zag "vortexes" for each layer. 

 

So.. I decided to change BB to slot 1 (along with PVA) and AA to slot 2 (with PLA). And re-slice it (that's why my first pictures show a different shape brim than the last  ones).

Ran a forth calibration, but now with BB on slot 1, and AA on slot 2, and X was at -5 and Y at 3 (the polarity reversed).

The print was calibrated, as you can see in the pictures above, the filaments align properly on the build plate. 

 

PS: All calibrations were made with the help of at least another set of eyes, so human error on segment alignment should be minimal.

 

PS.2: After switching printcores from slot to slot, one odd thing started to happen: The PVA "prime blob" stopped getting dragged by the nozzle to the print "area" at the start of the print. The PVA (never the PLA) has always been dragged up until then.

 

17 hours ago, gr5 said:

Z calibration is not stored  when you change a core because you may have touched one or more of the 3 bed leveling knobs since the last Z calibration it's not valid anyway.

 

This doesn't apply cause I've been calibrating and re-calibrating a lot. And didn't touch the knobs whatsoever, I just perform auto-level on Z.

 

17 hours ago, gr5 said:

2) But with the post above it sounds like you have a completely different issue where the print head is knocking the PVA apart?

Exactly. Because after all the calibration and print and calibration and print, I managed to calibrate it.

But for some reason... I noticed that a part of the PVA cylinder was off-center:

-Was it knocked by the nozzle earlier and I just saw it afterwards?

-Or was it printed off-center = dis-calibration mid print?

 

And then yes, it was fully knocked by the nozzle, getting out of the build plate.

 

17 hours ago, gr5 said:

3) Also your screenshot above seems to show that the C shape is support and the column should be PLA but in the photos above that is backwards - did you swap filaments in addition to the cores?  I don't recommend that unless you reslice as it will be using the wrong temperatures.  Which could explain #2 above.

 

Not so sure what you mean. In the pictures above, the PLA is orange which relates to the light blue in the slice. And that's exactly what I want. And yes, I swapped cores (with the respective filaments) and resliced it.

 

17 hours ago, gr5 said:

4) Please clarify which issue you want us to tackle first:

A) XY calibration issue between the two cores or

B) Bad alignment part way through a print.

 

I would say A) but I'm afraid B) could be a product of A).

 

This is my best attempt at a summary of what's been happening

 

 

[ATS_DEMUC 0]

29 minutes ago, ATS_DEMUC said:

-Was it knocked by the nozzle earlier and I just saw it afterwards?

-Or was it printed off-center = dis-calibration mid print?

 

Answering myself, after I tried to print again, I think it's just bad printing + lack of adhesion in between layers of PVA.

I was printing at 35mm/s and 210 degrees, and it just print really poorly. Sometimes, when the BB nozzle stops printing, it drags the print (or parts of it), and that's what de-centralized it (broke it) in the previous attempt.

The brim lines look great, but the print lines (small 8-6 mm diameter circles) look awful (check the picture of the latest print). Why?

 

The filament is brand new, so problems with humidity shouldn't exist. And I'm printing the same filament (but 1.75mm diameter) in a Prusa and it looks great.

 

17 hours ago, gr5 said:

4) Please clarify which issue you want us to tackle first:

A) XY calibration issue between the two cores or

B) Bad alignment part way through a print.

 

32 minutes ago, ATS_DEMUC said:

I would say A) but I'm afraid B) could be a product of A).

 

So: A) might already been solved but, it is left to be explained why did I get such different calibrations with the same core setup. I'm afraid of the structural state of this 3D printer. We've received this printer in the office from another department. For all I know, it could've been printing in the rain up until now. The 1 extruder PLA prints look decent, just a notch below Prusa. Double-extruder PLA prints tend to have issues (material dragging and a really bad mis-calibration one time but could've been lack of proper XY to that setup). PLA+PVA prints worked great once, and then stopped working. But the inconsistent XY calibration is, at least for me, a clear red flag that something isn't right.

 

B) isn't really bad alignment, it's just bad quality print, right? Or could it be firmware? Calibration? I'm running out of options. 

 

 

 

[gr5 2,172]

Well 16 seems crazy large - my printers had values usually at zero but I think one axis went as high as 3 on one of the printers.  But if your bottom layer looks centered and it does for example in the photo immediately above, then I suppose it's working.  But having 16 and then -16?  No that seems wrong.  Unless you swapped cores.  But you said you didn't.  I'm wondering if something is loose.  With nozzles cold I would open the front door on the head and hold the nozzle tip in my fingers and gently jiggle it left/right/front/back.  Sometimes the entire print head rocks in the Y direction.  Actually it's rotating around the X axis.  This is a known problem for some printers related to some plastic breaking inside the head that holds the Y bearing - the one where the Y rod passes through the head.

 

Anyway be gentle - just a pound or half kg of force at the most.  It isn't all that hard to snap the core at the heat break.

 

4 hours ago, ATS_DEMUC said:

Not so sure what you mean. In the pictures above, the PLA is orange which relates to the light blue in the slice. And that's exactly what I want. And yes, I swapped cores (with the respective filaments) and resliced it.

No it's the light blue that's the PVA.  The print itself is "more important" and gets more colors (red for outer shell, green for inner shell, orange for infill.  Support and brim typically both get that "light blue" or teal color.  Sometimes it's hard to tell them apart.  Anyway, I'm pretty confused about which is your print and which is your support - the blue parts in the cura screen shot don't look connected/continuous.  So it looks like the white PVA matches with the red center part.  I guess maybe it's the angle?

 

too skinny?

 

Well your print is pretty skinny.  You should at least have "support horizontal expansion" set to (default?) 3mm so that it's one continuous section of support reaching all the way to the print bed.  So that the support doesn't have to rest on top of the PLA and rely on the PLA for support.

 

I guess I would print your model sideways.  Then you don't have so many issues of things breaking off and falling while printing.

 

Note that PLA doesn't have to be kept particularly dry but PVA absorbs humidity like crazy.  Just 24 hours of sitting in normal air can make it such that you need to dry the PVA.  If it's a bit wet it gets more snowy and if it gets very wet you can see steam coming out of the nozzle and you can hear pop and crackle and sizzle sounds.  To dry PVA unspool enough for your print and without cutting that from the spool place it directly on the print bed with the spool on top and heat the bed at 55C for about 8-12 hours with a towel or blanket on top. 

[gr5 2,172]

It would help if you could post the project file.  Do "file" "save project as" (and tell me your cura version).  That way I can see your model and cura settings and I can slice it myself and look at things from different angles.

[ATS_DEMUC 0]

2 hours ago, gr5 said:

Well 16 seems crazy large - my printers had values usually at zero but I think one axis went as high as 3 on one of the printers.  But if your bottom layer looks centered and it does for example in the photo immediately above, then I suppose it's working.  But having 16 and then -16?  No that seems wrong.  Unless you swapped cores.  But you said you didn't. 

 

Exactly. On 3 consecutive calibrations I got 3 different values. And I'm not crazy, I double and triple checked every calibration with my peers. 

 

2 hours ago, gr5 said:

I'm wondering if something is loose.  With nozzles cold I would open the front door on the head and hold the nozzle tip in my fingers and gently jiggle it left/right/front/back.  Sometimes the entire print head rocks in the Y direction.  Actually it's rotating around the X axis.  This is a known problem for some printers related to some plastic breaking inside the head that holds the Y bearing - the one where the Y rod passes through the head.

 

Anyway be gentle - just a pound or half kg of force at the most.  It isn't all that hard to snap the core at the heat break.

 

 

I open the fan case, and I don't find anything wobbly. With decent pressure I guess the whole printhead moves but just 1mm or so, in positive X direction. But I don't think that's an issue(?).

 

2 hours ago, gr5 said:

No it's the light blue that's the PVA.  The print itself is "more important" and gets more colors (red for outer shell, green for inner shell, orange for infill.  Support and brim typically both get that "light blue" or teal color.  Sometimes it's hard to tell them apart. 

 

Trust me, the blue is the PLA. I'm printing a PVA tube with PLA support. I know that's not what people usually do, but I need a hydrosoluble tubing. And since I can print with two different materials, I use that to make supports that detach from the print easier (in PLA, instead of using PVA also).

 

2 hours ago, gr5 said:

too skinny?

 

Well your print is pretty skinny.  You should at least have "support horizontal expansion" set to (default?) 3mm so that it's one continuous section of support reaching all the way to the print bed.  So that the support doesn't have to rest on top of the PLA and rely on the PLA for support.

 

I guess I would print your model sideways.  Then you don't have so many issues of things breaking off and falling while printing.

 

The only reason I'm printing vertically, it's because I can have better round surfaces on the outside. When I print horizontally, I lose a bit of "roundness", if you know what I mean. Plus, vertically, I don't need support inside of the tubing.

 

 

2 hours ago, gr5 said:

Note that PLA doesn't have to be kept particularly dry but PVA absorbs humidity like crazy.  Just 24 hours of sitting in normal air can make it such that you need to dry the PVA.  If it's a bit wet it gets more snowy and if it gets very wet you can see steam coming out of the nozzle and you can hear pop and crackle and sizzle sounds.  To dry PVA unspool enough for your print and without cutting that from the spool place it directly on the print bed with the spool on top and heat the bed at 55C for about 8-12 hours with a towel or blanket on top.

 

Today arrived a new drying spool box to our office. I'm gonna try to heat the filament and repeat the print tomorrow.

 

 

2 hours ago, gr5 said:

It would help if you could post the project file.  Do "file" "save project as" (and tell me your cura version).  That way I can see your model and cura settings and I can slice it myself and look at things from different angles.

Ultimaker Cura 4.13.1. File attached.

I slowed down the travel speed because I noticed that was causing me unwanted dragging. Since the "tube" is, as you also said, "too skinny", the infill isn't uniform (see the green material on the attached picture). And in-between the deposition of the green parts, the high travel speed makes that it doesn't deposits the material properly, and drags it. If you look closely at the previous sent pictures, the brim always look nice, because it is only affected by "print speed".

This "travel speed" change enhanced my print, but it still isn't ok. I still cancel it after ~150 layers because the tubing isn't uniforms, and lacks material.

Also, I'm using Smartfil PVA:

Print Temperature 190 - 210 ºC

Hot Pad 25-60ºC

Fan Layer - Active

Layer Speed 30- 45 mm/s

 

 

UM3_actuator_v4_core.3mf

[gr5 2,172]

45 minutes ago, ATS_DEMUC said:

Trust me, the blue is the PLA. I'm printing a PVA tube with PLA support.

Oh wow.  Wow!  Very cool.  That explains it.

 

Okay so definitely look at how much PVA you are using (it says so near the SLICE button in cura) and loosen that much before drying it (so it is all exposed to the dry air).

 

Usually when PVA gets wet you get problems with the support but usually it doesn't matter because you don't care how ugly/broken the PVA is.  But in your case - you care quite a bit.  You should look into aquasys as well.  I hear that behaves much better than PVA.

 

Man it's going to be tricky to remove all the PLA.  PVA is usually pretty weak/brittle in comparison to PLA.  But I think it's doable.

[gr5 2,172]

Okay well that support up the middle of the tube is useless and can get in the way.  I'd use a support blocker to remove that.  And I'd also add some horizontal expansion to the PLA support.  I'll create a project file (based on your file) and post it here.

 

done.  I used 1.5mm for the horizontal expansion and had to block a little bit on all those semi-disk protrusions.

 

 

UM3_actuator_v4A_core.3mf

[gr5 2,172]

Another idea. 

I tilted it 45 degrees to reduce the need for support. 

Used tree supports to hold up some of it (it would otherwise fall over).

Set support angle such that it only supports a few places

lowered the Z value so it's below the plate (idea is you would make it a little longer and cut the bottom off at the end if you need it flush)

 

UM3_actuator_v4B_core.3mf

[tomnagel 126]

Hydrosoluble tubing sounds rather counterintuitive. Can you share what you do with that, just out of curiosity?
 

[tomnagel 126]

This is a useful testprint is you want to make layershifting visible.I have attached the project file.

UMS5_layershift.3mf

[ATS_DEMUC 0]

17 hours ago, gr5 said:

Man it's going to be tricky to remove all the PLA.  PVA is usually pretty weak/brittle in comparison to PLA.  But I think it's doable.

 

The first time I've done it, I've done it with Ultimaker PVA and PLA, and it worked fine (see image attached). But that PVA lost properties severely in the mean time. I was just waiting for this new dry box to repair it.

 

4 hours ago, tomnagel said:

Hydrosoluble tubing sounds rather counterintuitive. Can you share what you do with that, just out of curiosity?
 

 

So, in the first image, it's a hydrosoluble molding core. Alongside a PLA mold, and silicone to cast, I can create Soft Robots (in this case, just an actuator). The "tubing", which basically is just creating a "hollow" space in the core, is to pump water through it, to dissolve faster, when the casting is completely cured. In the second image, you can see it actuated with compressed air. 

Edited May 18, 2022 by ATS_DEMUC