Top Layers not touching - UM2

[Labern 774]

I had a similar problem on my UM2go but the side walls wernt touching also. They ended up requesting me to send the printer back and they will supply me with a new printer. UM will investigate what is wrong and report back.

I had tried heaps of different things but still stayed the same. and UM gave me ini files to print and I had the same issue.

[esteban-pacheco 33]

I had a similar problem on my UM2go but the side walls wernt touching also. They ended up requesting me to send the printer back and they will supply me with a new printer. UM will investigate what is wrong and report back.

I had tried heaps of different things but still stayed the same. and UM gave me ini files to print and I had the same issue.

so you mean we got an defect Batch of ultimakers? i have mine since july last year, i think is too late to send it back.... i#m having These Problems since the begining...

[Labern 774]

I had a similar problem on my UM2go but the side walls wernt touching also. They ended up requesting me to send the printer back and they will supply me with a new printer. UM will investigate what is wrong and report back.

I had tried heaps of different things but still stayed the same. and UM gave me ini files to print and I had the same issue.

so you mean we got an defect Batch of ultimakers? i have mine since july last year, i think is too late to send it back.... i#m having These Problems since the begining...

Well I'm not sure if it's a defect batch. I went through the whole thing part by part and couldn't find a reason. Ultimaker got me to calibrate some things and print some files but issue was still there.

So hopefully they can find the cause and it's an easy fix.

[Nicolinux 288]

Well if you look at this thread, I doubt it is an easy fix...

But lets hope your new printer will be fine.

[baymaker 1]

Man, I was so full of hope when I saw this post going on for 38 pages, thinking that finally someone else was having the same issues as I did, and hoping that I'll find a fix in there, but unfortunately, I just got to the end, and no luck so far ... .

I'm really struggling to find what could be going on wrong and explaining these issues ....

As most who have this problem, I've already tried replacing ptfe coupler (like 1 month ago maybe), check the bowden tube, opened the feeder to clean it all up, but so far, nothing has made any kind of improvements ...

What I don't really understand is that this issue just "appeared" out of nowhere, that some models would print perfectly fine 2 days ago, and now I can't get a single layer for a "large" flat object to print decently ...

[baymaker 1]

I'm not sure now that I've been reading some many issue/fix posts, but I was wondering what firmware was everyone experiencing this running.

I know that I would probably never have done the update if I haven't changed the electronic board, so I was wondering if maybe that could be linked to this ?

I'm going to take the head apart this afternoon, not sure what I'll be looking for but it can't hurt to give it a look, especially since the printer is not working in the meantime ..

[baymaker 1]

Would there be a way to "group" all the topics related to this issue ? I've found 3 "active" ones so far, and we pretty much all have the same issues, with the same fix suggested. I'm thinking it would probably be more efficient if everyone focused on a single topic page, that way we could probably avoid repeating some information, and group all the information in one place, and who knows, maybe the 39th page will be the one where we finally come up with a solution !

I found this post : https://ultimaker.com/en/community/view/9513-underextrusion-need-help-with-this-one?page=2 , and Illuminarti's answer got me thinking that maybe my print head assembly is wrong, with the nut being screwed too far into the nozzle (all the way down, without forcing, but without leaving a full turn unscrewed as shown in the picture either). Because of this, the teflon is not sitting as far down, and maybe this creates some gap somewhere, that could slowly get filled by melted plastic, which would probably affect the flow in a pretty "random" way, that could generate the fluctuations we see in the infill ? I just took apart and reassembled my print head yesterday, so I'd like some confirmation or advice before getting back to disassembling it again, but I'm thinking that maybe this could be what's causing our issue (which would be awesome !)

If nobody knows about this I'll give it a shot this afternoon and post my results.

[baymaker 1]

I THINK I FOUND IT !!!!

I just disassembled the head yesterday and replace the teflon coupler that was roughly a month old (yeah, I'd been printing a lot but still), and was a bit surprised to see how used it already looked. With the new one I've been able to print again, and it looks pretty perfect, but I just found out that the assembly manual (actually I first just found out there was an assembly manual for the UM2 available to the public !) that the teflon coupler IS sitting too high into the nut. I believe that the reason for that is that 'for me at least), when you replace your teflon coupler, you may first screw the nut back into the nozzle, then try to put the teflon, and soon enough, nothing works on the printer anymore ... I may be wrong, but I believe this is caused by extremely premature use of the teflon coupler caused by too high a pressure from the spring.

When checking the manual, I saw that you're actually supposed to first place the teflon back into the nut (where it should be able to slide in all the way), put that back into the metal plates, and THEN screw it into the nozzle, stopping once you have a gap about 1mm between the teflon and nut ... I just stopped a print I had going on (which was turning out pretty perfect so far otherwise) to dismount the head and do that adjustment. I'll launch a new print right after and let you know how it goes.

Maybe this won't make any difference, but that would explain why people with new parts that they just replaced are experiencing issues, and could explain the randomness of who's experiencing the issue (I also saw on another thread that some people had this mounted wrong from the factory, so that could also explain the issue on brand new printers ..)

I'll adjust it all and keep you posted on the results.

Hopefully that will FINALLY solve it !

[baymaker 1]

Ok, I don't want to celebrate too early, but I've been printing for about 2 hour now, and not a single issue, perfect layers, smooth as can be. So, still not fully celebrating as I'll wait for this part to finish printing, but I think it's safe to fill the fridge with champagne just in case !

[Labern 774]

i'm not saying you haven't fixed your problem but Mine came from the factory and had this issue. Even the test block printed using the printer had this issue. So i'm guessing the would have installed it correctly. I also replaced it using the method you have described but the problem was still there. Different slicing did make it show more then others.

[baymaker 1]

Huh, too bad, but I saw on a different thread that some printer came from the factory assembled the wrong way on that part, so depending where yours was assembled, you may have had this issue from the beginning .. If so, it would probably be worth it to replace the teflon coupler, even if not used that much, it had probably been under a lot more stress and pressure that it should have, which may have made it degrade much faster ...

I'm still recalibrating everything, but I've had a couple prints coming out pretty great from the printer since modyfing this. Maybe I was having a different issue, but the pictures and problems experienced where very very similar (at least from the pictures I saw).

[Nicolinux 288]

And to add more weirdness to the problem, check out this two pictures. On the far right, the strands do touch, on the left the don't. So the problem occurs not only for entire prints, but also mid-print...

To me it looks like the bed changes its leveling/distance from the bed minimally.

[3dnerd 6]

Hello baymaker,

since I (still) have the same problem, could you please explain more detailed how to assemble it your way?

- What do you call 'the nut'?

- What is (exactly) to do to solve the problem?

Some drawings/images (if you can provide) would be nice.

Thanks!

[esteban-pacheco 33]

And to add more weirdness to the problem, check out this two pictures. On the far right, the strands do touch, on the left the don't. So the problem occurs not only for entire prints, but also mid-print...

To me it looks like the bed changes its leveling/distance from the bed minimally.

 

im having the same problems in here, i just turn the material flow to 110%, i ve changed all in my printer (except the build plate, the frame, and the motors ), maybe is a design problem, i hope the ultimaker guys take notes and try to solve this...

[shurik 87]

Just to let you all know that I'm also in this problematic-top-layers club.

And exactly as on the photos above, sometimes they do touch and sometimes not, during the same print. Weird.

[Labern 774]

I received my replacement printer a few days ago and It doesn't have the problem. Yay for me, stink for you guys. Just hope they find the problem with the old one a report back. At least they have a sample printer.

[Dim3nsioneer 557]

And to add more weirdness to the problem, check out this two pictures. On the far right, the strands do touch, on the left the don't. So the problem occurs not only for entire prints, but also mid-print...

To me it looks like the bed changes its leveling/distance from the bed minimally.

 

Have you checked btw if the extrusion rate is the same for the two xy positions? So we would finally know if it is a problem of the z axis or of the e axis.

Personally I have seen this issue as well on my UM2 with Ultimaker black PLA. With other PLA brands even in black I do not or much less see it.

[Nicolinux 288]

I've done so many tests on this issue, I don't know if I checked the extrusion rate for both axes...

What would be the best way? Print a rectangle in different orientations? Since infill is done in an obliquely I would need to match the rotation of the object to have the infill lines go in x direction and with another print to go in y direction. Does this sound right?

[esteban-pacheco 33]

well, theres must be a REAL solution for those that cannot return the printer and get a new one, right?

im using this settings for a 0.35 nozzle:

110% flow rate

mat temp: 222 C* (Blueish White ColorFabb)

solid infill speed at 20 to 25 mm/s

outline speed 40 mm/s

fan min speed 50 %

fan mix speed 60 %

this settings works almost all the time, but,  this issue is so erratic that from time to time, even if im printing with using the above described settings the problem just appears...  i've made many many tests, there. this issue is so frustrating...

(i've observed that the fan speed has smth to do, its like wen using 100 % fan, the thin cord coming out of the nozzle looses quickly its temperature and theres a consequent reduction of its diameter -  but im just guessing)

Edited August 23, 2015 by Guest

[Nicolinux 288]

I have the Olsson Block and the issue is still there. I've also changed the temperature sensor and fan shroud. The next thing would be to swap boards but my motivation is kinda low.

[DidierKlein 729]

I have had this problem on my extended just yesterday. Printing with Architect Stone White (Faberdashery).

Maybe i'm just lucky or it isn't the real problem of top layers not touching but here's what i did and what i understand.

To me it's clearly related to some underextrusion, in my case i had tightened the four lead screws a bit more (careful not too much!). I have seen several posts where playing with these screws helped solving underextrusion.

I also tightened the spring in the feeder (Robert's feeder), the spring is compressed to 13mm approximately.

And finally i had to increase the temperature to 230°c (printing 0.2mm layers at 40mm/s).

[esteban-pacheco 33]

I have the Olsson Block and the issue is still there. I've also changed the temperature sensor and fan shroud. The next thing would be to swap boards but my motivation is kinda low.

 

please make a cubus (50 mm x 50 mm x 5 mm - or something similar). i also have an Olson block, i also changed the temp sensor, i also changed the heater cartridge for an 35 W and use my Settings and tellme what happens...

[Nicolinux 288]

@exteban-pacheco: I will.

In the mean time, here is something new. I am experimenting with colorFabb XT-CF20 and while printing with a 0.8mm nozzle, it got so full of filament on the outside that I had to pause the print and wipe the nozzle clean. Check this out:

Right before I paused the print, the filament strands did touch. Then after the pause they didn't and after a while they touched again. Now the standard pausing procedure on the UM2 is to retract some filament and move the nozzle to the front left while holding the temperature (fan was off for that print). When the print is resumed, it would extrude some filament first and then continue the print. However, there is some oozing involved and even with the extruding right before resuming the print, some filament is "lost".

I guess this reinforces the theory that this issue is strongly related to under extrusion because "losing" filament is the same as "not enough filament extruded".

[neotko 1,417]

I have not tested colorfabb cf but formfutura carbonfill made the same think on the nozzle until I used the fan. FF carbon does stick really really well to the bed at 70C or cold bed with blue tape so I could just pop the fans at after the fourth 90% and the amount that the nozzle dragged of filament was close to nothing. Also I didn't notice any problems with layering by poping the fans so it was all great.

[esteban-pacheco 33]

@Nicolinux:

well i was testing the new cura (15.06.03) if you use a 0.4 nozzle, and you turn up the top/bottom line width to 0.5, it gives good results, i think is a good option (you don't even need to set the flow rate to 110 %), but, cura has still some bugs... but that option is great...

Edited August 29, 2015 by Guest