Nicolinux

Ahh good to know. Thanks! But how do you know it? Is there any documentation on it?

Oh and there is something else I noticed. I am printing a ball bearing filament roller right now (http://www.thingiverse.com/thing:21435). The fans on the side did not run. But as soon as I gave each a slight tug, they started turning. I've had this happen before, but only on the right fan. Could this be an indication that there something wrong with the board? Something along the lines that it doesen't provide enough current?

@Chrisp: The nozzle was clean. I could see it all the way down to the tip. Besides, I think it wasn't clogged to begin with. The filament that I pulled out at 90° had a nice finish. If it were clogged the surface should have bumps and holes. But thanks for the disassembly tip. Splitting the lower part of the head from the upper was actually the hardest step. I am glad if I can skip it. Sadly the extruder clicked right before I saw underextrusion. I also tried once to "help" him by pushing the filament in. This really seemed to help because the skipping stopped and underextrusion was gone. But when I let it go, I saw how the filament was pushed back out and the extruder started skipping again (and underextrusion occured). By the way, the two white switches on the extruder do not move a notch. I don't want to break them, but I cant move them at all. The one next to the knurled bolt - I can't get a flat screwdriver between the switch and the black margin. It pushes very hard against it. The other switch I can move down a bit but it jumps back as soon as I remove the screwdriver. Are these switches intended to be flipped when there is no filament in the extruder?

I am on it. Look what I'v got in my mailbox today

Forgot to mention. When you turn the metal piece beneath the teflon coupler, it moves the nozzle and the teflon coupler up against the bowden tube. If the bowden tube is held firmly in place, both sides are pressed against each other. I have now 0 play with the bowden tube.

Ok, I disassembled the head. Here are my findings. Before I started to take the head apart, I took the bowden tube out and followed this procedure to remove a potential clog (http://umforum.ultimaker.com/index.php?/topic/3561-ultimaker-2-extruder-nozzle-blocked/?p=28940). The filament tip looks alright when I took it out at 90°: Next I started to take the head apart. It isn't very hard. I followed braddock's advice and taped the black plastic parts together so they stayed at the top. Then I unscrewed the fan holder and moved it out of the way to the back: I had to unscrew two more screws to split the lower part of the head from the upper one. Then I took the teflon piece out. It was in perfect shape: When I took upon the nozzle, I noticed that the exit was somhow obscured. I then ran a fine wire through it and I guess something changed because it then looked much better: After I put everything together I ran illuminarti's test (no retraction). Did not went well until I straightened the filament and held in my hand the whole time... When it came to the retraction test, it failed at the end. I got lazy and put the filament on a broom leaning on the side. When I wasn't around for two minutes the filament must have tightened to the point where it started to underextrude :/ I let it finish the print and some areas recovered well. Conclusion I guess it is the extruder. Somehow it is extremely sensitive to any resistance from the filament. This wasn't always the case since I have printed some objects before without any problems. So I need to take the extruder apart. But what am I looking for? The small white switches are already at the top (I guess at maximum strength). Maybe the extruder does not get enough current - but how do I check that? This thing isn't documented at all.

Compare this with my print... Interestingly enough just before that I printed another object (without retraction) that came out just fine (under the given circumstances). But ok ok, I know. Enough bitching, off I go to take this thing apart

Hey Chrisp, thanks for the offer. I will disassemble the head first and if it doesn't help, I'll tackle the extruder next.

Never printed with something other than Ultimaker PLA. But I noticed that there are differences. The silver one looks a bit grainy when it is hot - compared to other colors like orange or white. But since I'll take the head apart anyway, I will look for a partial plug.

Sounds good. Would be an easy fix if one could actually access the teethed gear without taking the extruder apart But Sander, could you read the entire post? There are hints that the UM2 underperforms at normal speeds when retraction is enabled. gr5 and illuminarti plan to test the speed/temperature/flow limits so new users would have some guidelines when it comes to printing. But I am sure that you guys have already performed tons of tests with the new machine. Would you mind to share some data?

This could be, but given that others have used this setting (5mm at 35mm/s) I believe it to be safe. I could try another test with slower retraction.

I took a closer look of my last pencil monster print. There is one spoot where underextrusion stop mid-layer. This makes it even more totally random and weird.

Ok, will do.

Ok, thank you for the time you took to look through the code. I believe you that it is related to retraction. While I took the video(s), I didn't hear any clicking. There is sometimes a very quiet, regular ticking. Maybe that's what you ment. Not a full click-back but rather many small jumps. If I hold my finger on the extruder I feel it stuttering very slightly.

Yes I have read that post. 0.25 layer height at 90mm/s seems crazy compared to what I have here. I'll take the head apart soon, hope there is a defect that can finally be fixed. Only then I'll accept the fact that the UM2 is slower with retraction on

I didn't hear the extruder skip steps, but I am not 100% sure. I wasn't around all the time. However, I thought UM's are pretty fast. At what speeds do people print stuff when quality doesn't matter all that much? 0.1 layer height takes forever so right now I am printing almost everything at 0.2. I remember Simon's post (link) where he statest at the end that the limits of a 0.4 nozzle are between 8-10mm³/s. And with these settings I am not asking even half of it. This should really be tested, and I look forward to it. Won't do it myself though due to lack of time.

Good catch. Second test run (the objects in the front). Now the regular gcode one also features underextrusion. And I thought I might be onto something...

Printing with 0.2 layer height and 40mm/s is too fast? Retraction was set in both cases to 5.5mm and 35mm/s.

Sure, these are short prints (20min). Will do it when I get back from workout.

Another update since I still haven't got the time and motivation to disassemble the head. I printed the exact same object with the same settings twice. Only switched between Gcode and UltiGcode. The difference is striking. No underextrusion with normal Gcode. So here is another theory. It is not a software problem only but maybe a combination between UltiGcode and the firmware that leads to underextrusion (maybe a problem with the extruder controll). @braddock and Chrisp: Did you guys solve the problem? If not it might be an easy test to switch to regular gcode and print a test object. Here are my settings and the link to the model (link) Regular Gcode: CURA_PROFILE_STRING:eNrtV8Fu20YQvRJGP2KOKRqzS0pK4gi8JLVzaYoAVlHH F2JFDsWtSS6xu7QsCfr3zi5JibKlNGlyKWAdJPFxZnZm9s1bsuArVHGOYpGbiPmh t+RFEZtcJHcVak3QG0+hUTwxQlYxVnxeYDRTDXpaFiKNCxdg7xBQjExQjBQrLcwq CplXyfW6wFiLNVLAsVcrUZlY14hpNGbdpcGyRsVNozAKR0fQMDoCjo6B4x04x/Qg 8KuJp5u6lspEM9kkuagWMG9EkdYFN+jZ70yqMuZpjpoKjv6QFfYucdrwIsYHoxp3 7500ubcUNcZGLlFFV7zQOADie1k0JUbBxJNyTfXnAou0M6Me8RIpxVTQryH30L8Y P4Vt1U/A0TFwPASzQi6jgDGfDbevbfloMsR4KZvKRBP/AHWldreCV4f3SlHFdHGP Be32wZ1ElnNqacuPQw9RHvSOEgu9uTRGlgdsG3ly/jcmxA5R3VkrT96jKnjtMiKA mtmu3RUTTKxRF6klY3uDeCcqx8T22polUhYu/Y61gnZn4mW8J3baMftO0G4XokKq yHWggxa8jkYUp73qqyqwWpi8y8QGyxpatZupNnyXK2P7q7jkDw7ZJZURSjwlwnRg jpwGTGSm40w7cUbWwwFsS28RV27XMEu7nrgOb0PvwYcVUUcbXiV2Kl/v8PUQtva1 ULyws9tmMVeiHDaHGq14Ru3gaiEqKthdOQNd88TyIfA7mznX+Gi/97h1WYqUWmnT cTjNMKqMJ4dO4eObQ08rPw9xLpUStKNxUzmSW1Fb0WDy3fidtpkftaEEZY1VPBdG HzMgblvFu6eqjTBOWjqzumioMdQtouMielHUwZnf0zxBW0T8EJ0Hj6AVQT/RPijj LxKZYjS9LkSCKXDzFjYpX23tt0H6sTzenk3fcS0S0GgMra3fwu+W5NDykFyKgdRv 4S8ql2w2h3q/hSuiCsFDCafQn6yagl2H7nV62y561SkOUIPS1rFVoFY8tuUAWrZr LwZeidRm6GWvKerH4ILB9eaoiG9h+mdFSuP8jQSeprCSjQK5rIBsYWALlhk2HLvY hfvaUE/CfAgD6D5TUlxFzb7nRYP67ANl29/hc5rLxiDUkppHxKLNOKMEXvcGbk9h KUwOJkcgQQCZZRT9Ddww+MxsdJphuPn1s82JlAGwSjWNvXZGt6xLwRrdPjUJ4DaY +AyuNkOh3HYOdsn+mIPU1hlMypIqCOFyV8T+M12jks7JaXdK7W3lzq5zFTIGl6NH Hp0hjMqSCgOrakCpJXffvgjwBReVW+qwGGJkY8Dtpz3CS6IuXyDICn5//xvoRCFW 1PTgNXzqbHzf96hH/SxdVil8eE9/7daM4fpIVoNa7BTRqCm3UR+DMTvp4OxSR8O9 C7wQmeUV5FQCCPMzdSKAr/hMFdJWkaYckInacXlOLRkx9i/O7gBuWdYPHAcSMMqP 9t/SOnP9sxbtQ9pLyydaFUmQQcsS7RY6zijqMY2C49cvzJ9QDhO4OQ+JsvbrONtu oam7JTl1vM9olw3eYwWltGH39P9iUadG4yVl6xK1hyYIDZII0uW+5Kuzj2/Gp4Nq gzXNum4H8eJ0Dken23MTHT7L9A+Q6fH3y3Sr9rPgWKTwP4Viz2fHl86O2Qktm14v 7YOQXcV6hiQAvZ5+z3kTsOPnTcB+6IHj1jrfHH8n2p7N2FcVnQmlzf+p7B90zoYn DtoZ+8az1voEz+fz8/n8Pedz92Y7fJvagfuHwval+8DIIQMLhaR/CfqJvqcIbtIv Owrujv92/udoljQcrr6kUcp1s2er7bXbU0J26EtY5uSwGzan8mVTGFEXu4lV2u/G u6XZ6BVcTRhjPTjb9IZba3CzoRfj+GELn90fehi5dX/W2yeTbsM9ivYPz9WJkg== UltiGcode CURA_PROFILE_STRING:eNrtV8Fu20YQvRJGP2KOKRqzS0qKnQi8JLVzSYIAVlHH F2JFjsStSS6xu5QsCfr3zi5JibKlNGlyKWAdJPFxZnZm9s1bMucrVHGGYp6ZiPmh t+R5HptMJPclak3QpafQKJ4YIcsYSz7NMZqoGj0tc5HGuQuwdwgoxkxQjBRLLcwq CplXyvU6x1iLNVLAoVcpUZpYV4hpNGTtpcGiQsVNrTAKwyNoGB0BB8fA4Q6cYnoQ +IJ5uq4qqUw0kXWSiXIO01rkaZVzg579nklVxDzNUFPB0SdZYucSpzXPY3wwqnb3 3kqTeUtRYWzkElV0zXONPSBeyLwuMApGnpRrqj8TmKetGfWIF0gppoJ+DbmH/uXo KWyrfgIOjoHDPjjL5TIKGPNZf/u6lh+ivJB1aaKhP+qjrtj2VvDq8F4hypguFpjT fh/cSWQxpaY2DDn0EMVB9yiJ0JtKY2RxwLeBJ6d/Y0L8EOW9tfLkAlXOK5cRAdTO Zu22nGBkjdpIDR2bG0QiUTouNtfWLJEyd+m3vBW0P9R13lE7bbl9L2i/c1EiVeQ6 0EJzXkUDitNcdVXlWM5N1mZig81qWrWdqiZ8mytj+6u44A8O2SU1I5SYSpRpwQw5 jZiYmZY1zcwZWfVHsCm9QVy5bcMs8TrqOrwJvQcfVkQebXiZ2Lm82OHrPmztK6F4 bqe3yWKqRNFvDjVa8Rm1g6u5KKlgd+UMdMUTy4fAb22mXOOj/d7j1mUpUmqlTcfh NMWoZjw5dAof3+x7WgF6iDOplKAdjevSkdzK2opGk+8G8LTN9KgNJSgrLOOpMPqY AXHbat6CqjbCOHFpzaq8psZQt4iO8+hFXgVnfkfzBG0R8UN0HjyCVgT9QvugjD9P ZIrR+CYXCabAzRvYpHy1td8G6cfyeHs2fsu1SECjMbS2fgMfLMmh4SG55D2x38Jf VC7ZbA4VfwvXRBWC+yJOoT9bPQW7Dt1rFbdZ9LrVHKAGpY1jo0GNeGyLHrRs1p73 vBKpTd/LXlPUj8FrBjebozK+hfGfJSmN8zcSeJrCStYK5LIEsoWeLVhm2HDs9S7c t4Z6EuZ9GED7GZPmKmr2guc16rP3lG13h09pLmuDUElqHhGLNuOMErjoDNyewlKY DEyGQIIAcjaj6Jdwy+ALs9FphuH29y82J1IGwDLVNPbaGd2xNgVrdPfUJIC7YOQz uN70hXLbOtglu4MOUltnMCoKqiCEq10R+894jUo6J6fdKbW3kTu7znXIGFwNHnm0 hjAoCioMrKoBpZbcf/8iwOdclG6pw2KIkbUBt5/2EC+IunyOIEv48O4P0IlCLKnp wQV8bm183/eoR90sXZUpvH9Hf+3WDOHmSFa9WuwU0agpt1EfgyE76eDsUkfDvQu8 EDPLK8ioBBDmV+pEAN/wGSukrSJNOSATtePqnFoyYOxfnN0B3LCsGzgOJGCUH+2/ pfXM9c9aNI9pLy2faFUkQQYtC7Rb6DijqMc0Co5fvzF/RDmM4PY8JMrar+Nsu4O6 apfk1PEuo102uMASCmnD7un/1aJOjcZLytYlag9NEBokEaTNfclXZx8vh6eDaoMV zbpuBvH16RyOTrfnJjp8lumfINPDH5fpRu0nwbFI4X8KxZ7Pjq+dHZMTWja+WdoH IbuK9QxJADo9/ZHzJmDHz5uA/dQDx611vjn+TrQ9m7BvKnomlDb/p7J/0jkbnjho J+w7z1rrEzyfz8/n84+cz+2bbf9tagfuHwqbl+4DI4f0LBSS/iXoJ3pBEdykX7UU 3B3/zfxP0SxpOFx9Sa2U62bHVttrt6eE7NCXsMzIYTdsTuWLOjeiyncTq7TfjndD s8EruB4xxjpwsukMt9bgdkMvxvHDFr64P/Qwcuf+rLdPJt2GexTtHzOwieY=

It could be. It is winter here in Germany. I noticed that if I want to have something stick like hell, I'd use the gluestick, smudge it around with a bit of water and then set the heated bed to 75°.

I took your settings and made sure to check them before _every_ print. 5.5mm at 35mm/s

Nothing changed, retraction was on. Here are the complete print settings: layer height: 0.2 shells: 0.8 retraction: on bottom/top: 1.2 fill: 20 speed: 40 temperature: 230 bed temp: 65 support type: touching buildplate (15%)

Well that's weird. I don't have time right now to take the head apart so I just changed filament and printed again (same settings, nothing touched): There is still underextrusion, albeit hardly visible. Printed before with Ultimaker PLA (grey metal I think) and now with Ultimaker PLA gold.

I hoped to get away without taking the head apart. But oh well