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This is a new issue for me. I would check the power voltage with a volt meter (or even better with an oscilloscope) while the motors are moving. I mean the only thing I can think of that is likely to affect both axes: 1) You messed with XY stepper current. 2) power supply. 3) You messed with jerk or acceleration settings. 4) You messed with max speed 5) Arduino clock speed is completely broken and running at 1/4 or slower rate. I doubt you did 1,3 or 4 as those are very hard to change on the UM3 (need to ssh into the printer and edit json files). I've heard this sound before when I was calibrating acceleration and max speed and I set either of them too fast. Or if you set current too low or too high. So if the 24V was actually at say 10V (while axes are moving) that would explain it. Basically: white/larger PCB, or power supply, or firmware. I'd say 70% chance it's the power brick.

Did you create this part in sketchup. If so right click on all surfaces in sketchup that are gray and select "reverse faces" which will make them white and should hopefully fix your issue. If you didn't already - ALWAYS look at the part in cura layer view before printing it. If the hole looks wrong in layer view it's going to print wrong also. If it's not the sketchup thing (or even if it is) then look at it in xray view as well and if you see any red then thats the problem. If these hints are not enough to help you then show a screen shot of the part in normal view, layer view, and xray view that shows the problem.

Maybe we are on to something! And no one printed any "filled" filament like glowfill or carbon fill? Was this 7 pounds in addition to printing? Or was the 7 pounds the only load on the filament? Because just normal printing will put 5 to 10 pounds of force on the filament and the additional 7 would of course put it over the edge. No surprises there. Well maybe when you took the feeder apart (or am I thinking of someone else) you put it back together wrong? Maybe something is wrong with the feeder gears - maybe something is slipping in there? No - it grinds. You are going to have to take this feeder apart maybe. If you don't find anything obvious you can just get another one from your supplier. Feel the gnurls on the gurled shaft and see if they are no longer sharp. Or something is wrong with the spring tension. Or maybe I misundertood your test. Make sure you do this test with virgin filament that hasn't been ground down flat already.

Yes. That makes sense to me. When you retract you relieve the pressure and when you un-retract it goes exactly back where it was (if it is fast enough). Retracting shouldn't actually suck filament up through the nozzle - that would add air inside the nozzle and be bad. Feature X: So I was thinking the speed changes should be made more gradual in cura. When it's doing one shell and it knows the speed of the outer shell it should do a fixed seconds gradual speed change. Or maybe it should do a fixed distance gradual speed change. Say either 10 seconds or 300 linear mm? Or configurable? This thought was over a year ago. Then I was printing something with these multiple speeds (default profile) and it looked to me like it was gradually slowing down before printing the outer wall. But I'm not sure if this is true. I looked at the part in layer view with colors for speeds and didn't notice anything. I didn't actually look at the gcode. Could feature X already exist in Cura?

I wanted to do this without using DHCP but eventually when I tried the DHCP method I was like "well that was easy! I should have tried that first!". Having said that - if you don't know linux maybe it's time to learn a little? Maybe not. I agree that it would be great if you could set the IP address from the control panel.

If you mean only the bottom layer micro brim (if that's your definition of elephants foot) then the easiest solution for me is to set "initial horizontal expansion" to roughly negative half the diameter of the nozzle although this varies depending on your leveling. I recommend manual leveling if you are going to want to get this dialed in perfectly. leveling will not change on this printer for many months so no need to relevel all the time - once you get it dialed in you can leave it alone. I like to level low such that the bottom layer squishes really well but you get that "elephants foot" which can be fixed with "initial horiz expansion" set to around -0.2. But this feature can hurt really tiny features (features under 1mm across) on the bottom layer. Like the teeth on a tiny gear.

I tend to simplify. We all do. Otherwise I'd have to write a 300 page book to answer every question. The vertical holes are going to need more adjustment than horizontal holes. It helps to understand the problem. 1) STL files only include triangles. No curves. So your cad program which has a cylinder of diameter e.g. 10mm is converted into a polygon with e.g. 12 sides (this is a setting in your CAD when you export to STL). The points on the polygon are ALWAYS on the circle so they lines of the polygon will be INSIDE the circle so this makes holes smaller. This is a tiny, tiny affect. Increasing the points helps a bit but if you have too many points then the printer will get upset (it doesn't like it if your polygons triangles start to get much smaller than 0.2mm). Again this is not a big deal - this is a tiny effect. 2) The main problem is this - PLA sticks to itself when liquid. Like mucus. Like snot. Not like water. This makes PLA a wonderful material for this kind of 3d printing (FFF). PLA is also cooling extremely rapidly at first - in milliseconds it's already cooler and contracting - although this may not be important for our issue here. As you are printing the circle on a cylindrical hole that stretchiness is like a liquid rubber band and tends to pull inward. The PLA wants to take a short cut and not go all the way around the cylinder. It pulls inward. THIS is the main reason cylindrical holes are smaller than desired. The interesting thing is that the effect isn't a percentage of the diameter but more of a constant as far as I can tell. So it tends to be around a half mm - maybe 0.4mm - not sure as I don't usually worry about the last .2mm (but sometimes I do!). I suppose it would make sense that really large cylindrical holes don't need any compensation so maybe the compensation actually decreases as you get bigger? I'm not sure. yes, other materials won't have this problem but this exact property is what makes PLA so great (ABS is very similar). I've printed materials like PVA that don't stick to themselves so well and, well, it makes for ugly results. filled filaments such as brassfill, have this issue - some of them are 90% brass and they don't stick to themselves so well and it's a pain in the neck filament to print with. The solution is always to adjust in cad. If you need consistent tolerances better than 0.1mm regularly you should consider a different technology such as a resin printer like the form2 or a powder printer like what they use at shapeways. To get even 0.1mm consistent results you need to never change printers, temperature, speed or layer height or nozzle or filament *color* (yes different filament colors print differently - slightly). You probably even have to worry about air currents so use a front cover so that people walking by won't make your parts come out differently. Another common solution for some people is to drill out holes after you print the part. It seems a bit crazy but it's so easy to do since the hole is mostly there to guide you. Note that this issue of holes being smaller also affects every surface on your print that isn't a straight line. So any sharp corner (interior or exterior) the printer is going to try to "cut corners" a bit. But also the printer slows down on corners so over extrudes so exterior corners are more likely to sick out than in. Interior corners definitely will not be as sharp is one would want either. Again this can be compensated in cad or improved by slowing things down and keeping acceleration high.

No. Definitely not.

That's just thrown out there to get a number in your head -- to explain the concept of why speed changes are bad. I watch the printer. A lot. Like watching fish. And I pay attention. So for example on the UM2 with the old black feeder sometimes the stepper motor wouldn't have enough torque and it would skip backwards a full step. which is a lot. The filament wouldn't actually go backwards in the bowden but it would lose pressure. It takes several seconds to recover before it's printing properly again. Maybe it's only 5 seconds. This is especially obvious when printing infill on the bottom layer. On glass. Or I'd be printing a solid infill cube where all the infill lines are touching as a test of how fast a particular filament/nozzle/temperature combination can print. And I'd change the speed (tune menu). It would take a few seconds to equalize again. You can see the gaps between infill lines if it's underextruding and you can visually see if it's overextruding as well. If you slow it down it over extrudes for at least a second and then eventually reaches equilibrium. If you speed it up it underextrudes for a few seconds and then reaches equilibrium. Maybe it's not 10 seconds - maybe it's 2 seconds. It's an exponential curve so to be more accurate I'd have to say something like "pressure reaches within 1% of equlibrium in 2 seconds". Anyway, the point is this: There is a delay from when you do a speed change to when the pressure in the nozzle equalizes (due to many spring factors but the main one is the bowden tube which can stretch slightly).

Please post pictures of the issue from cura 15 and from cura 3.X with speeds all set to 30mm/sec.

Lowering jerk and acceleration may make your printer last longer or scare you less but that will also lower print quality (but will improve ringing). I like my acceleration as high as possible (mostly because I tend to care about dimensional accuracy of my parts). Lowering speed will increase quality and scare you less. If you are going to mess with acceleration be aware of the consequences.

I haven't printed with PC yet. But UM recommends their adhesion sheets: https://ultimaker.com/en/products/materials/pc

Every time you remove the bowden it tends to get worse. But don't let that discourage you from removing it. The fix is easy. Inside the collet (that ring that holds the bowden in place) are 4 tiny metal blades. They can scrape the outer surface of the bowden. It's not obvious, the bowden may look fine. Anyway... Remove the bowden and look in the collet to make sure the 4 blades are still there (one may have broken off) and make sure they look the same. Assuming the collet is fine (it usually is) cut off about 4mm from the end of the bowden. This way when you insert the bowden back in the blades will get a grip on a fresh location of the bowden. That's it. Fixed.

Definitely try cura 15.4. I still use it sometimes for my UM2. A very nice slicer.

It would be great if this was in the machine settings then I could add my own abbreviations to each machine type.

For my UM2/UM3 series printers I prefer a suffix as you don't get much of the filename visible. The most important thing in the file name is the printer type (not the printer name) followed by nozzle size (when I go to print an older file I need to know what nozzle to install). Prefix would be great if we could get this down to two characters: s5=s5 (okay to have long prefixes for s5) 3=um3 3e=um3ext 2=um2 g=um2go o=original 2e=um2ext Followed by "N" for nozzle and first digit of nozzle size: n1=0.15 or 0.1 nozzle n2=0.25 n4=0.4 n6=0.6 n8=0.8 n1=1.0 or 1.5 nozzle (yes this is a repeat of the 0.1 - most people will not use both in their lifetime and if they do they probably remember which print will use the small and which will use the large

I hope you have a UM3 as this is tricky without pva support.

flow affects feeder only. feedrate affects all 4 axes (x,y,z,e). PLA does not need to be dried. PVA, Nylon need to be dried. PLA will be fine. Filament that gets moisture in it will pop and sizzle while printing and it will come out all snowy and foamy and Matte. Brittle filament is only brittle for the portion that has been off the spool for 12 hours. The part on the spool will never get brittle. You should be able to bend PLA with your fingers into a U turn with a curvature similar to the outside of your thumb without it snapping. Brittle filament won't even get to 90 degrees before snapping like spaghetti. Well... trying the same setting in my version of cura (it's a different version than yours but hopefully the profiles are the same) it looks like the infill is at the highest volume at 70mm/sec, 0.42mm line width, and X 0.2mm layer height - multiplying those 3 numbers together gives me 5.9 cubic mm/sec. That's doable at 230C. It's pushing things a bit but any UM3 should be able to do that. Even an old tired one. I personally would lower all the speeds to 35mm/sec and do a long print to see if it fails at all. Please try my pull test - just put some filament in the feeder part way down the bowden and pull hard. It should be able to take 10 pounds without slipping. Just do it very roughly - just estimate (have a weight nearby or a scale to push on to compare).

There's 4 issues here. Let's take them one at a time. 1) Going down to .06mm layer is only going to improve dimensional accuracy in the Z axis. So if those cylinders and holes are the wrong height/depth this may improve that. For example if one of those holes is supposed to be 0.13mm deep it will actually be printed .1mm deep if layer height is .1 and .12mm deep if layer height is .06mm. I'm guessing the Z accuracy isn't your issue so I recommend going back to 0.1mm layer height. 2) Pillowing. Has to do with temperature and infill. Yes 17 top layers should have been enough! I guess it wasn't. Make sure the side fans are at 100% as this helps a lot with pillowing but since the 0.1mm layer height worked fine maybe you can ignore this advice. But if you really need 0.06mm layer height you could increase the infill to 90% and I'd set gradual infill on and set it to 0.3 step size (5 layers per increase of infill percent) and 5 levels of graduation. 3) dimensional accuracy. I assume you mean the holes and cylinders are too small. That's a common problem with FFF printing and PLA in particular. The best solution is to adjust the diameters in CAD. Sorry. You would have to do this for injection molding as well (well someone in china would have to do it) as injection molding you also have to do weird adjustments to the model to get it to come out to the correct final size - for example if you want a 90 degree angle in injection molding you usually have to go for 88 degrees in the mold. Something like that. After a while you become a pro at adjusting the diameters. I usually add 0.4mm to every vertical hole diameter (horizontal holes don't need adjusting). 4) Corners lifting. Personally I don't use auto leveling - if you are doing manual leveling then just turn the 3 screws CCW 1/4 turn (looking from below) to move the bed up a little which will cause the filament to squish a little better. If you are doing auto leveling you can turn the 3 screws after AL finishes but eventually you will run out of screw/spring space. Alternatively you can set "initial layer flow" to 150% so that the first layer squishs into the glass really well. In addition to squish it's good to have a very very thin layer of PVA glue on the glass. There are 3 easy ways to do this. One of the ways is to put a thin layer of glue stick only on half of the glass (put down stripes of glue stick) then spread it with a wet tissue such that you remove 90% of it and spread it extra thin. Heat the bed and wait for it to dry before printing - usually dry by the time the bed reaches 60C. Much more info on getting your part to never come loose here:

Do you understand the part about high pressure in the nozzle? And how there is a delay between when you speed up or slow down and when the pressure coreespondingly speeds up or slows down? It can easily take 10 seconds for the pressure to equalize after a speed change. So. Imagine you are printing a cube and that means a square on each layer (outermost shell. When it slows down for the corner it overextrudes because the corner is printing slower yet the pressure in the head hasn't changed much. The solution is to print it all at one speed - and the closest you can get to one speed is infinite acceleration and infinite jerk. So you do the highest you can afford. The jerk speed is typically 20mm/sec (this is not true jerk - this has to do with the speed at sharp corners - if jerk is 20mm/sec then it will for example slow to 14mm/sec on a right angle corner). If your printing speed is 14mm/sec then there is no slow down. PERFECT CORNERS. yay. But you don't have to go that slow. You can go 25mm/sec and still get stunning quality. Or 35mm/sec and get quite good quality. Especially since the acceleration is very high so it's only slowed down to 14mm/sec for a millisecond or so. If you lower the acceleration you will get much more overextrusion on corners and you get these bumps/zits which are basically happening on corners.

oh. right. 20C. Okay this is good - you are knocking down the list to fewer and fewer possibilities. #1 Okay well I don't want to discount #1. Let's pick a print that was particularly bad and please send me the layer height, line width (all of them), speed (all printing speeds), printing temp (all of them). Maybe a new print. And when it gets going bad if you notice try slowing it to 1/2 speed. As a test. From the TUNE menu. And a photo of the print. #9 - No need to check this. Parts of your prints are coming out perfect. Other parts are extruding at 50% at the most. #5 - Do you still have both AA cores? Are they both doing this? Is one worse than the other? I recommend you test the feeder pull strength. Put some filament in that does not reach into the print head. Half way down the bowden is fine. Go to MATERIAL/PRINTCORE menu then "Material 1", then "move". move the material at any speed (even stopped is fine - basically we need the stepper motor powered up and it powers off after about a minute if you don't keep moving it). Pull hard down on the filament. Have a weight handy and try to approximate how much force you have to pull before the filament slips. The UM3 should be able to pull 10 pounds. Maybe even 15. If it can only lift 5 pounds that might be the problem. My list is missing one: brittle filament. 19) Brittle filament. Espciallty with older PLA but even brand new pla can do this. If you unspool some (for example if it's in the bowden) for many hours (e.g. 10 hours) it can get extremely brittle and it can snap off into multiple pieces in the bowden. It's not obvious if you don't look for this. Then it starts printing just fine and at some point one of those pieces reaches the print head and gets hung up somewhere and the printer suddenly stops extruding for now apparent reason. This usually happens within the first meter of filament - once you get to printing the filament that was recently on the spool it should be fine from then on. If #1 checks out by my calculations and this feeder test checks out I think it's time to buy a 3rd core. Weird and complex things can happen in the cores. Some of them are defective in subtle ways. For example, PLA can melt, then expand, in parts of the core and then cool and get stuck. If the internal teflon piece inside the core isn't as long as it is supposed to be or if it's inner diameter is larger than it's supposed to be this can cause problems. Or gunk can basically get permanently adhered to the inside of the bore of the nozzle turning your 0.4mm nozzle into a .25mm nozzle without you realizing it. If the trumpet part at the top is overly crooked it can cause excess friction. If any part is smaller than 2.85mm it can cause excess friction. Who knows but it's easy to replace.

Is it possible to pass the filament through a bath of ice without it getting wet before it hits the feeder? That probably won't help if the gnurled sleeve is at 50C. This is a tricky situation. I think you need some kind of cooling at the feeder. I think you should visit a neighbor who has air conditioning just long enough to verify this is the problem. I guess another solution is to avoid PLA. Almost every other material can handle 50C no problem. Such as nGen. PET, CPE - those are pretty easy to print and don't get soft until around 80C.

Doh!! You are absolutely right. More likely the stepper motor is heating the gnurled wheel and when that reaches 52C the filament is compressed as it starts to get soft right around 52C. Without going back to page 1: is this a UM2 or UM3? A "plus" feeder found on UM2+ and UM3 is heat isolated between feeder and gnurled wheel but I suppose it could still happen. Not sure how to cool the gnurled shaft though. airflow probably won't help like it would for the stepper driver. the stepper driver needs to be cooled from around 100C but the shaft needs to be cooled below 50C.

There's just one feature like this. It's called "fuzzy skin". Please start a new topic if you have any more comments/questions on outer textures.

Wait - layers should not start on an outer layer, right? Maybe that's where the outer shell starts and ends?