gr5

Also I'm not sure, but I think when you select the material e.g. "generic pla" you can also select it's color at that point.

I didn't answer this because I don't know the answer. I saw this post a while back. But I'll answer a "different" question. Make sure you are in PREIVEW mode. Just below and maybe to the left is an option "color scheme" which it sounds like you have set to "material color". Try the other 3 options. I almost always have it on "line type" which makes it VERY clear what is PLA and what is PVA material.

Good question. Maybe someone else will also want to see the answer, so I'll answer this publicly. Messages are usually approved within an hour (or deleted if they are e.g. Viagra ads). Your message was approved long long ago. The longest a message has ever sat unapproved is probably 6 hours. After 3 posts have been approved you no longer have to go through the process.

This is unexpected. I hope someone else can confirm this. I do find different brands and even different colors string different amounts. Certainly larger nozzles string more. White filament in particular (regardless of brand) seems to string more and have different characteristics. I store many spools of filament with large amounts of desiccant, but not my PLA.

By the way, Ultimaker has some profiles that are intended for extra high accurate results. I think they are called "engineering" maybe"? I forget but here is a summary of how to get higher dimensional accuracy: Line width: 0.4 Wall thickness: 1.2 Top/Bottom thickness: 1.2 Speeds: 35-40 (all speeds, except travel) Jerks: 20 Horizontal expansion: -0.03 walls: 3 Inital Layer Height = 0.1 Slicing Tolerance = Exclusive Combing Mode = off Outer before Inner Walls = Checked

But he wants a different expansion for 0.631 holes versus 1.129 holes. Note that these are in some weird unit called "inches" - it would be nice if they were translated to mm for the rest of us to comprehend 🙂 But seriously, I don't really have a feel for what the error is without opening up my calculator which I'm too lazy to do (sorry). But to your point about having 2 models, one for FFF (aka FDM) and one for aluminum. I recommend you do have 2 models. Or use some kind of parametric CAD that makes it trivial to switch hole sizes. In my experience, enlarging all the vertical (keep in mind that the issue is different for horizontal holes) holes by 0.4mm is about right. But it sounds like you are seeing different enlargement amounts for different hole sizes. This is strange. Maybe something else is going wrong. But I don't have a feel for how much error we are talking about. Is it less than 0.1mm? Note that if you paid the typical $50,000 for an injection mold, some poor engineer would have to take your model and make tons of changes to it so that it could be made in an injection mold and the changes would be a lot more involved than simple hole sizes. Even 90 degree corners have to be changed by a bit (not sure if smaller like 89 or larger like 91 degrees) so that after it pops out the corners are back to 90 degrees. I know this is small comfort.

Yes I think your understanding is correct. However be aware that there is also a "print thin walls" option which I recommend you always check. This would have fixed your issue with the 1mm nozzle and the 2mm walls.

So when you installed cura it created a seperate, local, settings folder with lots of settings in it. Actually a huge tree of folders with hundreds of files. On a PC it's in something like %appdata%/cura On linux something like ".cura" maybe. No idea about Mac. Search through those files for ones named "Ender" or "Creality". One of those represents your printer. It probably ends with ".json". You can edit any of these and restart Cura. You can disable the prime blob in there maybe? By the way, if you completely delete this tree of folders it's like getting a fresh install of cura and if you restart cura it will recreate them all.

getting max volume out of cura set "travel avoid distance" to zero. disable brim and skirt both! disable prime blob more tips/details here:

So your printer should be able to print about 8X that volume per second. So something is seriously wrong. I'll give you a list of possibilities. I'd concentrate on cleaning the core. Quick diagnostic is to pop in the other AA 0.4 core and see if it's all better. CAUSES FOR UNDEREXTRUSION ON UM3 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) and .4mm nozzle: 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. Note that your "print speed" may be 40mm/sec but it may be printing infill at 80mm/sec so CHECK ALL SPEEDS. 2) Line Width larger than nozzle. In cura 3.X search in settings for all line widths. If any of them are larger than the nozzle diameter this can cause underextrusion. There are 8 of these in cura 3.2.1. 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) Bad core. Try a different core. It could be clogged, or something more complex like the temp sensor in the core. 5a) clogged nozzle - the number one most suspected problem of course. Sometimes a grain of sand gets in there but that's more obvious (it just won't print). Atomic method (cold pull) is the cure - from the menu do a few cold pulls. The result should be filament that is the exact shape of the interior of the nozzle including the tiny passage to the tip of the nozzle. If it doesn't look like that you need to pull at a colder temperature. You can do it manually instead of through the menu if it's not working right but learn through the menu initially. 95C is roughly the correct "cold" temperature for PLA. Higher temps for other filaments. Simpler cold pull (3dsolex cores only - doesn't work on ultimaker cores because you can't remove the nozzle): https://www.youtube.com/watch?v=u07m3HTNyEg 5b) 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 (rarely) 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 6) feeder spring issues - too tight, too loose. You want the tension such that you can clearly see the diamond pattern biting into the filament. You want to see at least 2 columns of diamonds. 4 columns is too much. You usually want the tension in the center. If the white marker isn't in the center, make sure the adjustment screw actually moves the marker. If not then someone put the feeder back together wrong. 7) Other feeder issues, one of the nuts holding UM2 and UM3 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. 😎 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 8b) 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. Having the wedgebot (link below) helps you feel this with your hand by sliding the filament through the bowden a bit to see if it is stuck. https://www.youmagine.com/designs/wedgebot-for-ultimaker2 9) Extruder mis calibrated. Maybe you changed equipment or a wire fell off. Try commanding the filament to move exactly 100mm and then measureing with a ruler that it moved 100mm within 10% accuracy. If not adjust the steps/mm (this is done by editing a json file on the UM3). 10) Z axis steps/mm. it's easier than you might think to double or half the Z axis movement as there is a jumper on the circuit board that can be added or removed. If the Z axis is moving 2X you will get 50% underextrusion. Your parts will also be 2X as tall. 11) Crimped bowden. At least one person had an issue where the bowden was crimped a bit too much at the feeder end 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. Similar to 8b above - use the wedgebot to feel how much friction there is in the bowden. 12) Worn Bowden. After a lot of printing (or a little printing with abrasive filaments) the bowden resistance can be significant. It's easy to test by removing it completely from the machine and inserting some filament through it while one person holds it in the U shape. Preferably insert filament that has the pattern from the feeder and fight the movement by applying 2kg force on both ends at the same time and then seeing how much harder you have to push it on top of 1kg force. UM2 feeders can push with 5kg force. UM3 can push quite a bit more. 5kg is plenty. 13) Small nozzle. Rumor has it some of the .4mm nozzles are closer to .35mm. Not sure if this is actually true. I'm a bit skeptical but try a .6mm nozzle maybe. This shouldn't be a problem on the UM3 which has very good quality control but try a different core. 14) CF filament. The knurled sleeve in the extruder can get ground down smooth - particularly from carbon fill. 4 spools of CF will destroy not just nozzles but the knurled sleeve also. Look at it visually where the filament touches the "pyramids". Make sure the pyramids are sharp. 15) Hot feeder driver. I've seen a more recent problem in the forums (>=2015) where people's stepper drivers get too hot - this is mostly a problem with the Z axis but also with the feeder. The high temps means the driver appears to shut down for a well under a second - there is a temp sensor built into the driver chip. The solution from Ultimaker for the um2 is that they lowered all the currents to their stepper drivers in the newer firmware. Another solution is to remove the cover and use desk fan to get a tiny bit of air movement under there. This doesn't seem to be a problem on UM3 even though it's the exact same circuitry but they lowered the current in the firmware. But it's worth considering if air temp is 30C or hotter. It would probably happen only after printing for a while (air heats up slowly under the printer). 16) third fan broken. This tends to cause complete non-extrusion part way through a print. In the door of the head. You can hear it come on when cores get above 40C. Without this fan several things can go wrong. It can take a while as usually you also need several retractions to carry the heat upwards. There are a few failure mechanisms and I don't understand them all. One of them is probably that the molten PLA spreads out above the teflon and sticks to the metal in a core or fills the gap at the base of the bowden in UM2. Later it cools enough to keep the filament from moving up or down. 17) Spiralize/vase mode. This is a rarely used feature of Cura but you might have left it on by accident? In this mode the wall of your part is printed in a single pass. So if you have a .4mm core and the wall is .8mm thick it will try to over extrude by 2X. This is difficult to do and may instead lead to underextrusion. 18) too many retractions (this causes complete failure) - if you have too many retractions on the same piece of filament you can grind it to dust. 10 is usually safe. 20 is in the danger zone. 50 should guarantee failure. You can tell cura to limit retractions to 10 per a given spot of filament. Do this by setting "maximum retration count" to 10 and "minimum extrusion distance" to your retraction distance (4.5mm for UM2 and 6.5 for UM3). 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. 20) The "plus" feeder can have an issue where the filament doesn't sit properly for one print and it permanently damages the arm inside the feeder as shown by this photo - the hole is ground down asymetrically: http://gr5.org/plus_feeder_issue.jpg 21) Filament tangle - the end of the filament can get tucked under a loop on the spool and this tangle can propagate from then forever to the end of the spool until you fix it. It will cause many many jam ups and slow then halt extrusion. Repeatedly. The fix is to remove the filament from the printer, unroll a few meters and respool and put back on the printer. Never let go of the end of the filament spool until it's in the bowden. =======

The thing I hate the most about inches. HATE IT. Is when I'm using a micrometer and it says the hole is 0.182 inches in diameter - then I'm like - okay what drill is that? With mm it's simple. If the micrometer says the hole is 2.99mm in diameter then I must have used a 3mm drill or will need one to make a similar hole. Same with screw threads, screw diameters, part measurements of every type and so on. Unless I already know the ratio (e.g. oh yeah - that's 3/16 of an inch) then it sucks converting between fractions and decimals all the time.

I think you want the feature "max comb distance with no retract". I've had to use that when printing > 200mm/sec. Otherwise it leaks too much during the combing step.

#2 - No. Cura programmers all are in Europe and feel that inches is a barbarian measurement. There is a barbarian plugin but doesn't allow you to view in inches (pretty sure). It only allows you to convert STL files from inches to mm. Metric is something you may just have to learn. I find having a metric ruler around and if you memorize 1cm (how big it is) a few times, it gets easy fast. The visible grid in Cura has 1cm (10mm) squares for reference.

mouse wheel zooms. Alternate: + and - keys (either on main keyboard or on keypad - doesn't matter. "=" works same as "+") Right click and drag to orbit (or the 4 arrow keys work if you click on the grid away from any part first) shift+right click and drag to pan I use all three of those actions. Everytime I use cura. Middle mouse drag also does something (maybe?) but I don't have a middle mouse so I'm not sure what.

Did you check *all* the speeds in Cura? There are 7 printing speeds I think. Did you check all 7? Usually infill is printed at double speed. 20mm/sec doesn't mean much. The *volume* is more important. The feeder is only strong enough to push at a certain volume. So for example 0.4 line width with 40mm/sec with 1mm layers (crazy thick layers!!) would be 40*0.4*1 = 16mm^3/sec. That's on the edge of what a UM3 can do. But if your layer height is 0.2, speed is 40, and line width is 0.4 then that's 1/5 the volume (thinner layers) and only 3.2^3mm/sec. Very easy to do. If you are still getting underextrusion at a volume of 3.2 then something is seriously wrong. But what was the infill speed? What was the layer height. Anyway, if the slower speed helps and if you had layers around 0.1 or 0.2 thick then you have a mechanical problem. Try doing some cold pulls. It's in the UM3 menu system. I think under maintenance maybe?

I'm not sure if you have A) bad slicing or B) underextrusion A) Can you show what this looks like in layer view please? Are there "holes" in the same spots as where you actual print showed holes? Maybe try checking the box "print thin walls". Also maybe try burtoogle version of slicer which deals with thin walls nicely. B) It could be ordinary underextrusion. If so try printing at 1/3 the speed just to see if that makes a difference. Also make *all* the printing speeds the same speed. There are many causes of underextrusion (dozens) but they are all improved by printing at 1/3 speed. You can do this from the TUNE menu on most printers including the UM3.

Quick answer is that the ratio of 2.85 to 1.75 squared is 2.64X or 1/2.65 is .377. So try 38% flow for a quick fix. For the proper fix, you need to tell Cura that your printer can accept 2.85mm filament. It's in the machine settings somewhere I think? I remember doing this once and it was a pain. First you have to tell cura that your printer takes that size filament, then you have to choose the new sized filament. Machine settings are usuall here: go to left side of screen in PREPARE mode. Click on your printer, then do "manage printers" then "machine settings", then "extruder 1". Then modifiy material diameter. I think you want to possibly save, exit and come back in? Maybe not? I don't know if I ever got this working.

I guess a better test at the end would be to do: G1 Y2 G1 Y1.5 G1 Y0.5 to see if it hits the limit switch before it gets to Y=0.

It may have hit the limit switch when you used the G1 command. Meaning if not for the limit switch it may have tried to go beyond 0,0.

Thinking some more, it seems tightening pulleys but also "travel speed" are the top 2 things to mess with. Let us know what it was. You are not the first to post about this issue for a prusa-like printer and most people fix the problem without sharing the solution.

It's losing steps or slipping. Oops I said it, lol. So when you go back to 0,0 it's homing and using the limit switches (or if it's not homing it still stops when it tries to go past the limit switch it just stops when it hits the switch). I believe the entire bed moves on a Prusa when you move Y so this is a common axis to slip or lose steps. The problem could be many things - the first things to check are jerk and acceleration. Make sure jerk and acceleration control are disabled in cura (one checkbox for each feature). Then there are other possibilities. Marlin (the firmware on Prusa and on Ultimaker printers) has a lot to be desired. You can exceed the steppers ability if you give it the right gcodes. So basically I'd set the speed to what you are used to on Prusa and then search for "speed" in settings and make all the printing speeds the same (by default Cura does 200% speed I think for infill for example). Most importantly lower travel speed by 50% as a separate experiment. Or just try everything and then undo each feature to see which one was the cause. Also just tighten any pulley that might be slipping - particularly the one on the stepper. Tighten the set screw - tighter than you think is enough. If you use an L shaped allen wrench and grip the short end of the L it should hurt your fingers. So tight that that wrench twists a bit. Scary tight. There are other settings that are different from prusa slicer that you don't need and might be contributing so: disable coasting disable "retract before outer wall" disable "avoid printed parts when traveling" (I doubt it's this one)

There's a saying: "Don't fix it if it ain't broke".

I have seen gcodes for hundreds of printers. I'm 95% sure only delta printers have 0,0 in the center so the solution in the post above should fix your issue. Maybe you could google "delta 3d printer" to realize how different those printers are from your printer.

did you not read my posts?