gr5

Rats I thought I replied to this a few hours ago but it got lost. Okay so first of all - I think you need to increase "horizontal expansion" here because that should make the pva connect to itself in the very areas where it failed. It should connect all the way down to the glass. Secondly that pva looks very white. Whiter than UM PVA. Could it be that it got wet? You can tell because it hisses and crackles as you print making a "snowy white" result. Kind of foamy or spongy because the water is boiling as it prints and adding air pockets. UM PVA supposedly is better at not absorbing water than other brands (I don't know - I haven't tried any other brands yet). It's best to keep the PVA super super dry. Keep it sealed up over night and with a fresh desiccant each time you open the bag. I have the kind of desicant that changes color when it's done and you can heat it and reuse it.

@shaun167 - pla doesn't stick well to pva. So printing on a "slab" of pva probably just isn't going to work. Well it will stick but if it's a large part - it might not stick well. However pva sticks to itself nicely. And pla sticks to itself nicely. So you have to design things so that pva goes "all the way down" to the bed. And that the pla also goes "all the way down" to the bed. That's very easy to do with 95% of prints but there are millions of geometries where this is difficult or impossible. But there are tricks. Workarounds. I'd like to see a photo of what you want the final print to look like. Think of it this way: PVA should be thought of as something that pla rests upon but does not stick to. So if you print a slab of pva and then try to print pla on top it won't work. But if you add 3 or 4 "legs" that connect down the layer of pla below (or to the glass below) then that will stabilize things and your print should be successful. This same concept is MUCH MORE IMPORTANT for PVA. It just will not rest on top of PLA very well. That is the purpose of the "horizontal expansion" parameter in support settings. Which is on by default. But with some part shapes that won't help.

It works for me. Maybe more details would help.

If you are teaching them engineering then I recommend tinkercad. It's a free website for designing mechical things. If you are teaching for example history, then maybe start with thingiverse and have them enter lots of search terms related to what they are studying. For mechanical projects consider having that be homework. have them look at their bicycle or home or fishing pole. Look at things in their life and think about how they can be improved. Have them ask their parents for ideas; what might help them in their work. Having a goal is incredibly motivating. For example building a mount to connect a flashlight to their handlebars. It's not an easy project. They will need hints about hinges and they can get hints on thingiverse or google. Creating something that will actually be used - that's motivating!

That lower photo above has walls that are too thin for the printer I think. Try setting "line width" in cura 2.X to a smaller value just to see if that is the issue. If so try the largest possible nozle size where it still prints. If your resulting nozzle size is smaller than .28mm then I would opt for a smaller nozzle. 3dsolex sells .25mm nozzles for um3. If a line width of .30 makes cura happy (or hopefully larger) then you should be fine with the .4mm nozzle. Consider maybe setting flow rate to 200% or so to compensate. You can experiment during the print in the TUNE menu to see how changing flow rate changes the look of the walls of that cowling (or whatever it is).

As you may have guessed the Z axis is probably slipping (moving too far) such that the next layer is severely underextruded (not enough inill). Does it always happen at the same heights with the same patterns? If so it's probably Z rods, Z bearings, Z screw, or Z nut. But I would also suspect the Z driver. Put a heavy brick or lead weight or something on the bed towards the back. Reprint something. If the gaps get much larger then your z driver is shutting off due to overheating. The problem gets better then it's the mechanics I mentioned. Start with the easiest - clean the z screw completely in the area where it fails (also try to feel for disontinuities). If that doesn't fix it and the break was helping then you need to take it all apart. I recommend replacing the Z nut first. That's like $1 for a much better nut than the default nut. While that's apart you can feel if there is anything wrong with movement when the z screw is removed. If so then replace the rods and z bearings.

You should be fine. The 25 degree cooler thing is most important. The worst that can happen is that you bake the pva too much and you clog the nozzle. Nozzles can be repaired but it violates warranty of the core itself because they have a delicate part but I created a video (I'm not an Ultimaker employee) to help you do that should you clog your BB core: on youtube search for: ultimaker 3 core disassembly by gr575

Sounds like you are doing 60mm at .1mm layer height and 210C temp on UM2. Well that should be fine. I wouldn't go any faster. Actually I think the quality might be better at 30mm and .2mm layer height but that's not your issue so let's forget about that. Here's my standard underextrusion notes pasted in for you but I'd look seriously at #3 and ignore #1. And I'm happy with my black feeder but consider getting a medusa upgrade or the "plus" kit. But you can fix this without upgrading your extruder. 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) 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. 2) Shell width confusion. Shell width must be a multiple of nozzle size. For example if nozzle size is .4mm and shell width is 1mm cura will make the printer do 2 passes with .5mm line width which is possible but requires you to slow down much more to make a .5mm line out of a .4mm nozzle. If you really want this then set nozzle size to .5mm so it's clear what you are asking Cura to do for you. 3) Isolator - this is most common if you've printed extra hot (>240C) for a few hours or regular temps (220C) for 500 hours. It gets soft and compresses the filament under pressure. It's the white part touching the heater block. It's very hard to test when not under full pressure (spring and bowden) so sometimes it's best to just replace it. Also if you notice parts of it are very soft (the blacker end where it touches higher heat) then it's too old and needs replacing. 4) Curved filament at end of spool - if you are past half way on spool, try a fresh spool as a test. 5) curved angle feeding into feeder - put the filament on the floor -makes a MASSIVE difference. 6) 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. 6b) Bowden pushing too hard - for the same reason you don't want the bowden pushing too hard on the isolator. 6c) 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. 7) 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. Or soak it in acetone overnight (after removing 90% of the material with cold pull). 8) 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 9) feeder spring issues - too tight, too loose 10) 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. 11) 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 11b) 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 "plus" upgrade or using the IRobertI feeder helps you feel this with your hand by sliding the filament through the bowden a bit to see if it is stuck. 12) 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. Not an issue on the UM2 "plus" series. 13) 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. 14) 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. 15) 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. 16) 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 - maybe there is a temp sensor built into the driver chip? The solution from Ultimaker 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. TinkerMarlin lets you set the currents from the menu system or you can send a gcode to lower the current. Ultimaker lowered the default currents in July of 2015 from 1300ma to 1200ma for X,Y,Z but left extruder at 1250. Other people (I think the support team of a major reseller but I forget) recommend X,Y,Z go down to 1000mA. M907 E1250 Above sets the extruder max current to the default - 1250mA. So try 900mA. This will only change until next power cycle so if you like your new value and want to save it use M500. You can just put these into an otherwise empty gcode file and "print" this and it will change. Or get tinkergnome marlin! You will wonder how you lived without it: https://github.com/TinkerGnome/Ultimaker2Marlin/releases M907 E900 M500

I recommend using a phone if you have a smart phone. They tend to take very good quality and can do macro. For publishing it I recommend youtube and then add a link to the youtube video in this topic. But... HOLD THE PHONE SIDEWAYS. Never take vertical videos. Please.

I don't thinks so - I think it copies it to the local "hard drive". Actually flash memory. If it does fail keep the bed warm so the part doesn't come off and it's possible to continue a failed print by editing the gcode file and basically removing the portion up to where you want to continue (but leaving some of the initial homing/priming part).

@dim3nsioneer sells some nice swiss filaments. Do you mean those small strings? Those are very small and easy to clean up. Not so easy to fix. I'm not sure what causes them but white filaments (all brands!) tend to be worse.

This is a common problem. The set screws inside the pulleys are not tight enough. Tighten the hell out of them. All 11. If you only found 8 you didn't tighten the most likely culprits - those on the motors and short belts.

Did you check the voltage at the fan pins on the PCB though? The wiring inside the sleeve is not dependable - there are little connectors in there and the wires can easily come loose that go to the fans. So check the voltage at the PCB first. The easiest way to turn the fans on is probably to select PRINT, then select any print then immediately go to TUNE menu and then set fans to 100%. The printer will not start printing until you exit the TUNE menu. I think.

There's a transistor (possibly a darlington) that can break easily in this circuit. If you are good at soldering surface mount you could replace it. Did it come with the original 12V fans that were mounted in series? Or do you need part numbers or something? Schematic for UM2 circuit board is here: ULTIMAKER 2 SCHEMATIC - click "raw": https://github.com/Ultimaker/Ultimaker2/blob/master/1091_Main_board_v2.1.1_%28x1%29/Main%20Board%20V2.1.1.pdf

It looks like it's drifting in only X or Y. Can you confirm which axis? Was it left/right or was it front/back? The drifting axis is the one you need to fix. Tighten the HELL out of the pulleys. There is a little set screw inside each pulley. There either 5 or 6 pulleys on each axis. Tighten them all but mostly tighten the two pulleys on the short belt that goes to the motor. Those are usually the ones that have a problem as those 2 have twice the torque placed on them. If you use that little L shaped wrench it should hurt your fingers. You should be scared of breaking something. The tool should almost twist a bit. REALLY TIGHT.

Are you trying to build marlin or cura?

Can you take a photo of the print head? Probably you just need to bend the left fan inwards into the head a bit. But show us a photo. It could be the fan is fine and instead you need to adjust the X axis limit switch a mm or so. Just bend it.

That's too big. Aim for about 2million polygons or smaller (about 30mb to 100mb or smaller). There are some great, easy to use programs to decimate polygons. This one is pretty quick and pretty easy to use. ACtually it might be slow to load the initial 500mb file but then it's pretty good after that: Meshlab: http://www.shapeways.com/tutorials/polygon_reduction_with_meshlab

Sounds like you have 2 unrelated issues. Both easy to fix if I understand correctly. Shipping the printer back will risk something else going wrong. I recommend contacting fbrc8 or your supplier and just getting some phone help. However we can help you here on the forum. First issue: "head is crashing into home position". Is it making a really horrible buzzing/grinding/vibrating noise? If so there is a problem with the x or y limit switch. one test is to push the head around by hand. You can hear it click when it hits the x and y limit switches. It's probably not touching one of them. Usually something needs bending by a tiny tiny amount. Visually looking and feeling where it should touch is usually the solution. Sometimes a limit switch wires falls out. Maybe you should just video what you are talking about. Maybe I am talking about something unrelated to your issue. Captcha? What are you talking about? The printer has no captcha. Cura has no captcha. If plastic is not adhering to glass that is definitely a leveling issue. There are many quick solutions. One is to do the Z leveling one more time but skip the paper - level right on the glass. After that plastic will stick much better to the glass. And disable auto leveling. This is just one simple method. There are other ways to get it to stick well to the glass. Also clean any oil from your fingers off the glass at least once per month.

>ok, my settinges were 175W/125W/35W/35W The higher the first value, and the lower the next 3 values, the more likely your power brick will shut down. The first value is your budget. The next values are what the printer THINKS it is using. So to be safer, lower the first value and/or raise the remaining. Bringing the first value from 170 to 125 is almost guaranteed to over tax your power supply. Because marlin thinks it's a wimpy 125W heater and isn't afraid to run it full on.

Are you using Cura? What version? I think the feature is called "roof"? It should be enabled by default.

How are you "importing"? "file" "open file"? "open file" icon? drag and drop? double click file?

What kind of printer is it? I guess not an ultimaker. I recommend pronterface. Not the cura plugin. The real thing. Repetier also has a great product (and is also free).

You are almost there! while it's printing if you push up on the glass you will see it works fine. So just rotate the 3 screws CCW until it's squishing nicely into the glass. More info in this video if you want to get your parts to stick well enough to swing the printer around with:

Don't worry about it being old. These are good machines. My UM2 is from the first few months when it started selling and it still works great. Definitely get the plus kit. Or alternatively if you want to save money then print out the iRoberti feeder with Meduza 2x and buy an olsson block and get a new teflon part. Doing all that is probably just as good as the plus upgrade.