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korneel

Again : walls\layers not touching : advanced question

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gents;

a bit of an advanced question.

first, the environment;

I have 3 UM2's, all upgraded to UM2+ printers. they work perfectly, very happy with them.. until today.

I am printing a complete BB8 for a customer, and one of the things they require is multiple outside layers. it is then that i noticed this:

210lon8.jpg

as you can see, the layers are not even close to touching..

so I did the standard things, performed an atomic pull, not debris at all..

then i changed the nozzle..

then the bowden tube..

then i cleaned the feeder..

then i placed a ferrite core over the cabling for the feeder..

then i sliced the object again with Simplify3D.. then with Cura..

and now.. I'm stuck.

my other 2 printers don't have this issue when using this filament.. so in short.. i have no clue what to do

i tried printing slower as well, hotter, i tried the tension on the belts, everything.. but I can't seem to fix it..

the material is Colorfabb PLA-HPA, and this just drives me crazy.. does anyone have a bright idea?

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Now that's really really frustrating I can imagine.

You have the benefit of having 2 machines to compare with.

I would take one of the working machines and start switching one component at a time from this working machine with the same component of the layers-not-touching-machine and start prints concurrently to see if the behaviour at some point changes.

I would start with some non-apparent things like physical placement of the machines (because it's easy; sometimes the location like a cold drag or similar could affect printing)

Then maybe the physical outlets.

Then switching the filament rolls.

Then perhaps change the electronics boards.

Then the entire print head assembly.

Then the feeder.

Then....the glass bed?

The heated aluminum plate....

....and, well, if you would have the endurance to go through it, it would be very interesting to hear about the results. Good luck!!

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hello everyone;

I have done the one thing that I always hate.. I have failed to reply to my own topic :(

so this is happening on 2 of the 4 printers. one is really bad with certain materials, one is just "normal" bad.. the other one has not problem. the one thing that differentiates them is the age.. this is 15K versus 10K versus 5K hours..

so i;'ve gone through some of the topics and it has been suggested that it might be the X/Y shafts.. so this is something I will change hopefully in the next 2 weeks since these have a long backorder time.. will keep everyone informed.

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I recently switched over to the bondtech and at that occasion also exchanged the stock bowden tube with a ptfe tube. the difference is really astonishing, even if you push the filament through without anything else attached. i could imagine that if there is some pressure, the friction is even higher. maybe exchanging the bowden helps and it is cheap to replace.

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The X/Y shaft have a clear effect on quality. I really suspect that this problem comes from there. Not really something that i was aware of but the atomic method can slightly bend them if you place the head in the middle of the printer (what i used to do to have an easy access.

Atomics should be done with the head in one corner, but again now i do most of the times lazy atomics this is less violent on the shafts

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Well if it's only on the older machines I would highly suspect the teflon isolator (the white part in the head) and the bowden as those 2 parts can wear out. Most likely the teflon part. Also Ultimaker (and 3dsolex) now sell a better kind of higher temp teflon and stopped selling the older (more opaque) white teflon parts.

I had an absolutely brand new um2 extended that did this. It was easily solved by increasing flow by 10% but it drove me crazy. I tried many things but never figured it out and I had to return the printer (it was a loaner from Ultimaker). But just increasing the flow to 110% worked fantastic so I lost some of my motivation to figure out the problem since it was printing so well with 110% flow.

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Also just one weird idea. Can you check the hotend, ofc the um2+ it's designed to now touch the olsson, but since it's a human the one that assemble it (I guess) maybe the metalfan it's touching any part of the olsson block? That could explain a cooler extrusion than intended. Just dropping ideas.

Edited by Guest

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How many hours have you been printing with the UM2+ upgrade?

I had this (with a pre-production upgrade) after approx 250 hrs ...

The teflon isolator was mounted with too much pressure on it. You could see deformations on the outside and the inner diameter was 2.9 mm! Drilled it to 3 mm now it's working again.

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The teflon isolator was mounted with too much pressure on it.

If that's the problem try loosening the 4 thumb screws on the heat a turn and the problem might go away.

Wasn't that fixed? I remember that @sandervg said something about the new hotend assembly had some kind of internal spacer to remove that assembly errors on um2+.

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It has an aluminum cylinder that replaces the spring but if you don't tighten the round nut enough (which raises the olsson block) then there's too much pressure on the teflon part.

Oops - I guess it would be a problem if you tightened it too much.

Yeah I mean part of this conversation.

https://ultimaker.com/en/community/20409-um2-upgrade-kit-first-impression-and-some-tips#reply-142752

The x4 screws are tight with a tool, so in theory they are at a 'correct' distance when they are assembled.

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I recently switched over to the bondtech and at that occasion also exchanged the stock bowden tube with a ptfe tube. the difference is really astonishing, even if you push the filament through without anything else attached. i could imagine that if there is some pressure, the friction is even higher. maybe exchanging the bowden helps and it is cheap to replace.

 

great suggestion! unfortunately, this is a new bowden tube and not the problem.

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Also just one weird idea. Can you check the hotend, ofc the um2+ it's designed to now touch the olsson, but since it's a human the one that assemble it (I guess) maybe the metalfan it's touching any part of the olsson block? That could explain a cooler extrusion than intended. Just dropping ideas.

 

great suggestion. I did however take care of this and this is not happening..

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How many hours have you been printing with the UM2+ upgrade?

I had this (with a pre-production upgrade) after approx 250 hrs ...

The teflon isolator was mounted with  too much pressure on it. You could see deformations on the outside  and the inner diameter was 2.9 mm! Drilled it to 3 mm now it's working again.

 

unfortunately that's not the case. I verified the smoothness of the filament movement (remove the print head and slowly slide some filament through the nozzle to feel for deformation) and they are perfectly fine. I hae also been testing with different pressure for a year now, so I've broken my fair share of couplers ;)

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He has upgraded them to 2+ so he has fresh TFMs in there, and fresh bowdens. It's a bit strange to say the least.

 

well, the upgrade has been done with partial custom parts (since I was testing quite a few things I did not need the complete upgrade package) so I have replaced everything except the X/Y rods.. I've ordered a new set.. let's see how that works out.

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I recently switched over to the bondtech and at that occasion also exchanged the stock bowden tube with a ptfe tube. the difference is really astonishing, even if you push the filament through without anything else attached. i could imagine that if there is some pressure, the friction is even higher. maybe exchanging the bowden helps and it is cheap to replace.

 

great suggestion! unfortunately, this is a new bowden tube and not the problem.

 

but did you replace it with a regular tube or a ptfe tube?

Edited by Guest

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I recently switched over to the bondtech and at that occasion also exchanged the stock bowden tube with a ptfe tube. the difference is really astonishing, even if you push the filament through without anything else attached. i could imagine that if there is some pressure, the friction is even higher. maybe exchanging the bowden helps and it is cheap to replace.

 

great suggestion! unfortunately, this is a new bowden tube and not the problem.

 

but did you replace it with a regular tube or a ptfe tube?

 

regular tube..

where can you buy PTFE tubes?

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I'm pretty sure that with new rods it will be perfect as the others.

I upgraded one of my UM2 with the upgrade kit and replaced the rods on my 2 years old UM2 and only that changed the print quality a lot (i also changed the block and temp sensor + new 35w heater and took the newest UM2 head i changed with the upgrade kit). Maybe the LMUU6 bearings from the head can add some friction also.

The feeder (Roberts) and tube are still the standard ones.

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