Ultimaker 3 - Problem with "raised edges" that are unfixable

[eaamarp 0]

Hello everyone

 

So I am running a Create space along with some other students at my academy and we have four ultimaker 3's

One of them is giving us a lot of struggle which I have tried solving by looking at every post in the forum regarding the nozzle touching the print.

We are experiencing that after a few layers of printing, the nozzle starts colliding with the print, as if there have been extruded to much filament and the layers become to high.

 

https://ibb.co/5cz4H7S

So our initial build plate was bent and we replaced it with a new one from a maintenance kit.

The cooling is set to 100% at all time and we also replaced the radial fan with a new one from the maintenance kit.

The Z screw is not making any noise when moving up or down and it is lubricated.

 

We are printing in PLA at a layer height of 0.1mm, print temp 200-210deg C, print speed is at 50m/s

Out of the four printers, this is the only one which is giving us trouble, which causes me to believe that it is a hardware malfunction somewhere.

 

I hope that I somehow described our problem well enough for someone to make a diagnose, because it is starting to drive me crazy 😛

Please let me know if you need any more info

 

Best regards

Martin Pedersen

[Smithy 1,144]

Have you printed exactly the same object, same settings on another UM3? 

 

Depending on your model, it could be that you print too fast, that's why I am interested if it is different on another UM3.

[gr5 2,167]

This is an extremely common issue with PLA.  It happens only when the walls are not vertical - when they overhang.  Just like in the photo.  This is very mild overhang yet pretty bad raised edges.

 

I tried dozens of variables and the only one that makes raised edges better or worse is fan speed.  You want the fan speed on 100% (which is default).

 

So the first thing that comes to mind is to make sure your two side blowers are at 100% when printing.  Cura by default turns them off on the bottom layer and then gradually turns them on and by about 1mm off the build plate they should be at 100%.  You may have a loose cable.  If you remove the rear two screws on the print head - the very long screws - everything is fine but now the top rear panel comes off (which holds the electric cable in place).  Reseat that cable connector and then put it back together but add a shim - add some blue tape around the cable so it doesn't pull out again in the future.

 

The other thing is bed temp.  The sensors aren't always identical so I'd put a little blue tape on the bed of a good and this bad UM3 and set the bed to 60C and wait 5 minuts and use an IR thermometer to check that the temp is the same.  It should be within 2C of 60C in the center of the bed.  If one is hotter then just adjust the temp in cura by the error (if bed is 65C then set bed temp to 55C in cura going forwards).

 

[gr5 2,167]

Oh one more thing - even though it looks bad while printing - it usually comes out fine in the end.

 

if your problem is not exactly that you have raised edges but that the raised edges cause the part to come loose well then that's a completely different issue.  I talk about many fixes for this.  I have done prints where you hear the head hit the print ("BAM!") but the print stays on.  I can pick up my whole printer by the tiny UM robot print.  How to get parts to stick real well is a long subject hence the 15 minute video - I know it's a long video but it explains so much!

 

[eaamarp 0]

Hello

Yes I have printed the same print on multiple printers and this is the only one giving me real issues.

I have already set the fan speed to 100% which made no difference.

The issue is not that the print is coming off the build plate, but the end result has some really jagged layers on the overhangs, which is not really acceptable at 0.01mm I feel like.

 

I will try reseating the cables in the back and report back later.

 

Edit:

I don't know if it is relatable, but after doing a bunch of manual leveling of the build plate, the screws reach a certain height. After this height have been reached, even though I do the manual leveling so everything fits snugly, when the printer afterwards tries to do active leveling, the nozzle hits the build plate before even starting to increment closer to the nozzle.

I might be totally off, but shouldn't active leveling be relative to the manual leveling or is it always starting from a specific point?

 

Best regards

Martin Pedersen

Edited March 13, 2019 by eaamarp

[Smithy 1,144]

3 hours ago, eaamarp said:

I don't know if it is relatable, but after doing a bunch of manual leveling of the build plate, the screws reach a certain height. After this height have been reached, even though I do the manual leveling so everything fits snugly, when the printer afterwards tries to do active leveling, the nozzle hits the build plate before even starting to increment closer to the nozzle.

I might be totally off, but shouldn't active leveling be relative to the manual leveling or is it always starting from a specific point?

The distance between the base and the aluminum plate below the glass should be ~14mm. If you are too high or too low, the leveling will fail and/or makes other problems. It doesn't matter if you have 13 or 15mm, but round about 14mm is a good start and you are fine.

[eaamarp 0]

Thanks Smithy

How do I measure the distance between the two?

My thought is to make a small printed block that can slide between the two plates while I adjust.

 

 

Edit:

So I tried remounting the cables for the fans, they fit snugly. I also tried cranking the space down to around 14mm so the active leveling was functioning again.

 

The problem is still there. My benchy is getting these ugly ragged layers on the front overhang.

Best regards

 

Martin Pedersen

Edited March 13, 2019 by eaamarp

[Smithy 1,144]

There is already a "tool" available.

 

Buildplate_distance_tool.stl

[eaamarp 0]

Thanks, but as mentioned, the problem still persists.

Any ideas how I should proceed?

 

Edit:

So, something new, I saw in another post about the 4 screws that is holding the z axis lead screw needing to be tight. I raised the build plate and tightened the screws (they were a little bit lose), but now when i raise the build plate I hear a bit of grinding as it is nearing the top.

 

Should I loose the 4 screws a bit again or is this a sign of grinding in the bearings inside the cover?

 

Best regards

Martin Pedersen

Edited March 14, 2019 by eaamarp

[geert_2 557]

Have you checked if the fans are running freely? Not (partially) stuck by sucked-up filament hairs and strings? Or no filament or other debris is covering the exit or inlet holes, or something mounted incorrectly, or something else along this line?

 

What could help, is putting a desktop fan in front of the printer, at its lowest speed setting. This provides a huge amount of fresh air at low speed. But of course, this does not address the source of the problem.

 

What also helps for overhangs, is printing in thicker layers, e.g. 0.3mm instead of 0.1mm. But that may not always be desirable for the rest of the model. Printing slow and cool also helps.

 

[eaamarp 0]

The fans are totally clean and running freely.

We don't really have a fan at our disposal and as you said, it does not solve the initial problem.

 

Best regards

Martin Pedersen

[eaamarp 0]

Hello all

 

So I found this post:

And tried doing some post manual and active leveling leveling(tuning the screws of the build plate at the beginning of the print).

This seems to have fixed the issue as far as I can see right now.

After doing a few smaller print, I tried this:

https://www.thingiverse.com/thing:2656594

The only place it messed up a bit was on the 90deg overhang and as far as I know, the ultimaker was never supposed to do that without support to begin with.

I will try a dual print later today to check for issues regarding the z offset.

 

Edit: I tried the dual print and now the second printhead is hitting the print. . .

 

Best regards

Martin Pedesen

Edited March 21, 2019 by eaamarp

[eaamarp 0]

So to me it seems like the offset between the two heads are not correct.

How would I go about fixing that?

[eaamarp 0]

I hate to be a bumper, but I have still not gotten any progress in trying to fix my issue.

Does anyone have fresh suggestions?

 

Best regards

Martin Pedersen