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Absolutely correct.

That would be due to underextrusion - at this temp the PLA is more like toothpaste (versus honey) and so you need to print much slower - about half the speed you were at or half the layer height. But if you are happy I would stick with those settings. Just be aware that you are "on the edge" of more serious underextrusion so one minor filament tangle may push it over the edge.

The feeder motor shuts off at I believe 170C so you need to keep nozzle temp above that. 180C to be safe or 175C if you are very daring.

I think that sharp corner issue may have had to do with parts that need to fit inside each other? In that special case you have to cut the corners a bit or spend much too much time with the file.

@lab I think your bed is too far from the nozzle on your bottom layer. it could be underextruding but I suspect you just need to move the bed closer. Don't use the leveling routine - just turn the 3 screws a full half turn counter clockwise. Also in your last picture it looks like you need a bit more fan. Make sure fans are well above 50% by the time it gets to that layer being shown. This probably means you need the fans at 100% by the time you are up to 1mm. You want them to come on slowly because if not the nozzle cools too fast for the PID controller to compensate (the PID controller needs a little time to adjust to the increased need for power). I'd like to see more photos @lab to see if you have underextrusion issues on other parts of the print.

This is a good read: http://support.3dverkstan.se/article/38-designing-for-3d-printing

You have very serious play or backlash (look up the term in wikipedia). Usually caused by loose belts as Sander says. Also paradoxically can be caused by belts too tight but this is very rare on the UMO. It can be caused by loose belts or high friction - either one will keep the head from moving all the way where it is supposed to go - kind of like a loose steering wheel when moving the wheel back the other direction has no effect for the first bit of turning. Push the head around by hand - there is quite a bit of resistance from the steppers but only that - you should be able to do it with your smallest finger on each hand pushing one finger on each opposite block. usually high friction on UMO is caused by the end caps being too tight - you can try loosening them a little and see if friction goes down. HOWEVER - it's much more likely that your belts are too loose.

That 125% is a serious problem - it means it is trying to put out more filament than needed for the standard .4mm nozzle - it's tough to squeeze out more filament than there is vertical space for it so the filament has to go out sideways which greatly increases the needed pressure. Also in Cura what is your shell width it MUST be a multiple of 0.4 or you can get the same problem (underextrusion). Also - probably most important of all - you are printing too cold, too thick and/or too fast. For .15mm layers here is the max speed I recommend for any given temp. This changes depending on layer height. Some printers can do double these speeds but barely and most printers can't: 26mm/sec at 200C 40mm/sec at 210C 53mm/sec at 225C 67mm/sec at 240C Also different filament colors vary and you might have to print hotter with a few colors. It's perfectly fine to print at 50mm/sec - quality will be lower but still pretty decent - so if you don't care too much about quality raise the temp to 230C (don't go over 240C) and if you want higher quality then lower speed to 35mm/sec and temp at 210C.

I call this "stringing" although this is extremely minor stringing - it's more caused by a tiny bit of PLA on the tip of the nozzle that comes off when it touches the pillar below. The best solution for this is to try a different brand or color of PLA. Some colors and brands are just worse. Lowering the temperature is the ONLY thing you can do if you don't change PLA. I usually print at 210C - different printers are different as the temp sensors can vary by +/- 20C (usually they are within +/- 5C) so tommy probably has a printer that prints on the hot side but having said that, you might be able to get rid of these pillars at 180C to 190C but if you go that route you need to also print MUCH slower. With layer size of .08mm and temp down at 190C I would stay well under 20mm/sec and at 180C I would stay under 10mm/sec. Here are typical max speeds for UM2 or UMO - I like to print at half these speeds - these are in mm cubed so you have to take this number and divide by 0.4 (nozzle width) and layer height (.08mm) to get max possible speed on a brand new printer:

OH MY GOD! You should have posted that a month ago!!! This changes everything. In layer view the printer stops on layers 31,32 do not print - nothing happens - it just skips from layer 30 to 33. No wonder! So the problem is in your STL model. There is a hoel in it somewhere such that cura can't make a complete loop so it doesn't know what to do with all the "random" line segments it has for those layers and so it prints nothing. if you look at the part in xray view as labern suggests you will see a red spot somewhere in those 2 layers. You need to fix that spot. Possibly you can fix this with the "fix horrible" settings but those might fill in holes that you need such as vertical screw holes so I don't recommend that. Also you don't need "support". I would turn that off - that's a waste of time and filament because it is supporting a surface that is "bridged" anyway and the printer is pretty good at doing bridging - especially with PLA. I mean the support doesn't hurt anything but it doesn't help either.

Sorry to hear that!

Email Carl one more time. He's very busy and was in Hong Kong for a while and the people he left behind running the store may have lost your order. But he's back and your email is probably buried. So just email him one more time. He's very kind to his customers - for example often offering a free extra nozzle as an apology.

I have to say words are not the best way to communicate sometimes. A video or photos is usually better. That way the term "grinding" is clear to everyone.

Maybe the problem is we disagree what "grinding" means. To me grinding is when the filament is ground down and you get a bite mark out of the filament. Or alternatively the filament is ground flat on one side so instead of a cylinder coming out of the feeder you get a half cylinder. I think maybe you just mean the "skipping" sound is grinding? If so that means everything you said is now taken in a new light and maybe you just have normal underextrusion which is a whole different topic than grinding or plugs.

Oh! That's normal. If nothing is coming out then it may be getting hung up on an internal ridge. Try cutting the tip of the filament to a point and reinserting it. Or go to move material and move it up and down a few times watching the filament and grabbing the bowden and pushing it a few different angles so the filament approaches slightly different each time. Usually what I notice is suddenly the filament starts moving again another 10mm before finally coming out of the nozzle. Alternatively you could have a plug. A small piece of sand or dust can get carried up through the bowden and into the head and cause a plug. Best remove with cold pulls or you can remove the whole nozzle assembly and burn it out clean. I guess reading all your posts I'm just completely confused. Are you saying you get nothing out of the nozzle during filament load? if you do get filament but it's skipping - that's completely normal. Or are you saying move-material works fine but when you print the print doesn't look so good? I think you should start over and explain what the problem is because I'm getting conflicting information.

You only had underextrusion in that one spot - it's not because of the temp or speed or feeder - it's because the layers below aren't high enough. At least I'm 90% sure. having filament down to 2.5mm would be (2.85/2.5)^2 or 30% underextrusion - I suppose that might be enough to cause what you saw - but it would be a problem in the entire layer - not just that one spot. I really doubt this is a filament diameter issue. I think it's just having trouble on the underside - maybe show a photo from the other side - I bet the layer looks pertty bad on the bottom side of that bad spot. Maybe if you could design some support structure underneath it would work out better. I could be totally wrong but in the photo it looks like it's only underextruding in that one spot.

This is very common - the whole thing is symmetrical and it can go together 2 differnt ways. I think you put it back together backwards. Don't feel bad - IRobertI did the exact same thing and he's very smart. The um2go is backwards from the UM2 and UM2 extended.

This is faulty material. There was a recent bad batch of UM PLA. Contact UM immediately: http://support.ultimaker.com At the same time you might want to order some PLA from a local distributor. Germany has some interesting filaments - google "PLA45" and "PLA90". Once PLA breaks in the bowden it will fail on a retraction soon after because occasionally that crack will get stuck in the print head well above the hot zone and then the print just fails because the filament is ground to dust at the feeder. If you have several spools of PLA it's easy to test it for being brittle. Bend it until it breaks. Repeat with good and bad filament. The difference is obvious!

Is the feeder stepper really hot? Sometimes it is hot enough to soften the PLA right at the feeder knobbed sleeve. Maybe you need to explain better about the "change filament" grinding. Is it happening only when the material gets into the head? Or when it is part way through the tube. You might want to remove the bowden at the feeder and inspect it for over-crimp there which can cause problems.

White prints pretty well for most areas (like walls) but it tends to be more liquidy. Less viscous. So it is more likely to leak/string and it doesn't do overhangs quite as well. But top surfaces should be fine. I tend to print white at a lower temp - maybe 15C lower. And then I end up also having to print slower because I'm afraid of underextrusion even if it's not necessarily a problem. I think you had trouble on that top surface because it is over an overhang and it took a while for the layers to "catch up". Maybe if you rotate the part so the circle is down? or increase infill to 24%? Or higher?

If the switch won't remove power then you have a strange problem. I would just return the PCB. Contact support.ultimaker.com

Wow! That's the problem right there! Do not leave the ABS at 250C for so long. It will turn into this gunk that is like gum left under a table for a year in a restaurant. Did you soak the peek part in acetone? Someone else asked if that is okay to do. I didn't know the answer.

CAUSES FOR UNDEREXTRUSION AND HOW TO TEST FOR THEM AND REMEDY THEM As far as underextrusion causes - there's just so damn many. none of the issues seem to cause more than 20% of problems so you need to know the top 5 issues to cover 75% of the possibilities and 1/4 people still won't have the right issue. Some of the top issues: 1) Print slower and hotter! Here are top recommended speeds for .2mm layers (twice as fast for .1mm layers): 20mm/sec at 200C 30mm/sec at 210C 40mm/sec at 225C 50mm/sec at 240C The printer can do double these speeds but with huge difficulty and usually with a loss in part quality due to underextrusion. Different colors print best at quite different temperatures and due to imperfect temp sensors, some printers print 10C cool so use these values as an initial starting guideline and if you are still underextruding try raising the temp. But don't go over 240C with PLA. 2) Isolator - this is most common if you've printed extra hot (>240C) for a few hours or regular temps (220C) for 100 hours. It warps. It's the white part touching the heater block. Test it by removing it and passing filament though it by hand. 3) Curved filament at end of spool - if you are past half way on spool, try a fresh spool as a test. 4) curved angle feeding into feeder - put the filament on the floor -makes a MASSIVE difference. 5) Head too tight? Bizarrely MANY people loosen the 4 screws on the head by just a bit maybe 1/2 mm and suddenly they can print just fine! Has to do with pressure on the white teflon isolator. 5b) Bowden pushing too hard - for the same reason you don't want the bowden pushing too hard on the isolator. 5c) Spring pushing too hard. Although you want a gap you want as small as possible a gap between teflon isolator and steel isolator nut such that the spring is compressed as little as possible. 6) clogged nozzle - the number one problem of course - even if it seems clear. There can be build up on the inside of the nozzle that only burning with a flame can turn to ash and remove. Sometimes a grain of sand gets in there but that's more obvious (it just won't print). Atomic method (cold pull) helps but occasionally you need to remove the entire heater block/nozzle assembly and use flame. 7) Temp Sensor bad - even the good ones vary by +/- 5C and bad ones can be any amount off - they usually read high and a working sensor can fail high slowly over time. Meaning the sensor thinks you are at 220C but actually you are at 170C. At 170C the plastic is so viscous it can barely get out of the nozzle. You can verify your temp sensor using this simple video at youtube - on you tube search for this: mrZbX-SfftU 8) feeder spring issues - too tight, too loose 9) Other feeder issues, one of the nuts holding machine together often interferes with the feeder motor tilting it enough so that it still works but not very well. Other things that tilt the feeder motor, sleeve misaligned so it doesn't get a good grip. Gunk clogging the mechanism in there. 10) Filament diameter too big - 3mm is too much. 3mm filament is usually 2.85mm nominal or sometimes 2.9mm +/- .05. But some manufacturers (especially in china) make true 3.0mm filament with a tolerance of .1mm which is useless in an Ultimaker. It will print for a few meters and then clog so tight in the bowden you will have to remove the bowden from both ends to get the filament out. Throw that filament in the trash! It will save you weeks of pain 10b) Something wedged in with the filament. I was setting up 5 printers at once and ran filament change on all of them. One was slowly moving the filament through the tube and was almost to the head when I pushed the button and it sped up and ground the filament badly. I didn't think it was a problem and went ahead and printed something but there was a ground up spot followed by a flap of filament that got jammed in the bowden tube. 11) Hot weather. If air is above 30C or even possibly 25C, the air temperature combined with the extruder temperature can soften the filament inside the feeder such that it is getting squeezed flat as it passes through the feeder - this is obvious as you can see the problem in the bowden. The fix is to add a desk fan blowing on the back of the printer. 12) Crimped bowden. At least one person had an issue where the bowden was crimped a bit too much at the feeder and although the printer worked fine when new it eventually got worse and had underextrusion on random layers. it's easy to pull the bowden out of the feeder end and examine it.

That's strange. That sounds like there is a huge friction in the tube itself. Is it possible you bought some 3mm filament by accident (instead of 2.9mm or 2.85mm)? when you had the bowden disassembled did you try pushing some filament through it? Does it grind even before the filament reaches the head? while it's still part way through the bowden tube?

I didn't know you could still buy a UMO "regular". I thought only the "+" was for sale. When you switch it off by the side switch - could it be the USB cable that *appears* to be powering the printer (but not the steppers of course)? That is normal. In other words - try removing USB cable and switching power off - does it still stay on? Well the UMO board has these things that are usually called "pololus" or "stepper drivers". They are socketed and there is one near each axis (X,Y,Z,E). You could try swapping the drivers for Z and X to see if the problem moves with the pololu. If so then they only need to send you a pololu maybe? Or you could buy a few - they are quite cheap (google pololu black): http://www.pololu.com/product/2128