gr5

First please don't use the word "backlash". That has a specific meaning. A synonym to backlash is "play". It means something is loose and when it switches direction, nothing happens initially. Like 30 years ago I had a car where there was 1cm of backlash in the steering wheel - when I would pass through from right to left there was a moment where the steering wheel stopped turning the wheels and you could feel it took less force for a moment. Anyway you can call this "feeder clicking" or "feeder skipping back" or "feeder skipping". It's very common with the original UM2 and was "fixed" with the UM2+. Anyway to the problem - when you are doing move material like this it is common for certain filaments so this may be normal. More likely I'm thinking this material is ABS. I have a spool of ABS this exact color. Or this could just be normal. did you try printing with it? If you are getting feeder skipping on the first layer that might be normal but if you get any on the second layer then it's a serious problem and very fixable. Let me know and I can send you the list of underextrusion causes but my first guess is this material is not PLA.

I think you are seeing a pattern that is not there. The blue lines sort-of match what the part looks like but really I think it's a perfect curve except there are 2 horizontal lines each at a different layer. I'm not sure what causes those 2 lines - it could be that the Z axis didn't move the correct amount or it could be under or over extrusion just near this one corner caused by a speed change. If this printer is pretty old I would clean the Z screw and add one drop of oil to each of the vertical rods. If you decide to use tape - use any painters tape - most commonly found in blue but also green (frog tape). You want the widest possible tape. You MUST clean it with isopropyl alcohol. If you don't then the part won't stick very well to the tape and may come loose during printing.

So I would consider maybe turning autolevel off so that you get 100% consistent results. The glass is not as flat as you need. Even if it was, the plate beneath it can easily bend it by 0.5mm from one end to the other. So you would have to flatten the system, not just the glass. UM uses tempered glass - I believe only because it's safer if it does break. But tempered glass isn't as flat because of the way it is made. You can put tiny shims such as washers under the glass and adjust them until you get it flat enough. That is probably the path I would take (shims and tempered glass) combined with disabling autolevel, combined with only using a portion of the bed (tempered glass tends to be thicker in the middle so possibly printing around the edges). Most prints only need leveling to an accuracy of around 0.2mm or 0.1mm. So I suspect autolevel has an accuracy of around 0.1mm or possibly even 0.05mm. Which is of course much to course for you.

This is underextrusion and is the most common problem that people run into with 3d printing. The bottom layer is extra complicated because leveling affects it so much. Your underextrusion is only about 20%. However it looks like you showed us a tiny bit of the second layer as well and it's also underextruding by a bit. The most common cause is simply "printing too cold and too hot". 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 To get no underextrusion at the above speeds your feeder needs to push 3mm filament with about 2kg of force (1.75mm filament with .7kg of force). Most feeders can push twice that hard. So the above speeds are conservative. These temperatures are for Ultimaker2 and different printers differ a huge amount as the nozzle is always cooler than the temp sensor but by how much is different for every hot end design. So another test is to fight the feeder. See how hard you have to pull on the filament to make it slip backwards. This will let you know if the problem is in the cold end or the hot end.

STL files don't specify units. Which is a problem with the STL specification. So there isn't an easy way for Cura to notice. However if the model is too large to fit by say 1000X then cura automatically shrinks it down so you can at least see the model. It would be nice if the model is < 1.5mm that it would pop up a message or something to see if you want to scale it up.

Benchy - at the default size - is too small to need brim. You need to watch my video. It's a bit long but packed with information.

This has nothing to do with fan speed but I do recommend a *little* bit of fan for ABS. I'd do the minimum fan. 240C seems a bit too cold for ABS. Anyway I don't know what your problem is - clearly it's major underextrusion but I don't know why.

I tried ice water and boiling water and the temp probe was quite far from 0C and 100C so I don't recommend that.

sketchup is not great at making 3d models but you can do it if you follow these tips: https://i.materialise.com/blog/3d-printing-with-sketchup/

Unlike UMO, UM3, S5, the UM2 series printers expect you to set things like retraction distance on the printer (not in cura). When you are in cura if you select a UM2 printer it should not even let you enter a value for retraction in Cura. However if you tell Cura (in machine settings) that you want it to generate reprap style gcodes, then cura *will* have a retraction distance. And when you go to print this gcode file the UM2 will even pop up a message warning you that "machine settings will be overridden by this gcode file". Or something like that. Are you asking about the a UM2 series printer? Because only the UM2 printers should allow you to set retraction distance (and a few other settings) on the printer.

Short answer: Using CAD software. I'm not sure exactly what you are asking. When you put "solid" in quotes the first time - that's probably for a good reason. I think you mean "hollow"? Or maybe you are saying you want some parts of the model to have light infill - say 20%. And other parts of the box to have 100% infill? Is that what you want? That can be done in Cura. Here is a video to explain the second thing. Maybe you want a 3rd thing and just need to draw a picture of what you mean:

That's as expected and as I predicted - the slot with the wall was tighter. I'm not sure why they are tighter than expected but probably because the nozzle is 0.4 but the default line width is something like 0.35. This is a less precise way of printing. The above parameters are for all prints where you don't care how it looks but you care how well it fits. You can get even better quality by slowing it down to 25mm/sec or faster, worse quality by speeding it up. Notice I didn't specify the layer height as most people understand exactly what that gives you. I usually do 0.2mm layer height for practical (not pretty) things as the best way to speed up a print is thicker layers. In my opinion. The thing that the above suggestions will hurt the most is ringing. So if you have text on the side of your print it will look pretty bad. But when you measure the area of the ringing with calipers it will be quite good. Even with this more accurate profile, sometimes you will want greater accuracy and you will have to fix the last little bit by tweaking the cad model.

Just scale up by 25.4. It's trivial to do. Click on the part in sketchup, click on the scale tool on left side, choose 2540% Sketchup has lots of other issues so you should read this: https://i.materialise.com/blog/3d-printing-with-sketchup/

I see you have "brim only on outside" checked. It's working as intended. It's only putting brim on the *outside* of the inner circle in the D. Not the answer you wanted, sorry.

I'm guessing the one on the right is a wider gap. It's the same reason vertical holes are too small. PLA acts like a liquid rubber band milliseconds out of the nozzle. It's like snot. It's also rapidly shrinking before it becomes a solid. So it pulls inward when you make a small circle or square or corner. Because it pulls inward corners and things tend to "shrink" inward. This happens before it even solidifies. It's much worse on corners as it's pulling inwards. It doesn't affect flat sides so much but can reach pretty far from corners. That wall on the side of the left slot helps anchor things and keeps the slot accurate at the wall. You may think it's a pain to compensate for these errors in CAD (the best solution) but keep in mind for injection molded parts you have to do all kinds of crazy design considerations and hacks/adjustments as well. It's just that you don't know about these because the engineers at the injection molding factory are doing the adjustments for you (and it costs a lot). e.g. 90 degree corners - if you want to be accurate have to be adjusted by a degree or so in cad. Crazy stuff.

So this part looks like it's functional and doesn't need to be pretty. I'm hoping UM comes out with a functional/accuracy profile some day. Until then, try this. Parts will look worse, but fit better. All printing speeds at 40mm/sec (or 25mm/sec for super high quality). This is critical as at the speed change from infill to shell it will over extrude briefly and underextrude when speeding back up. disable acceleration control disable jerk control set initial horizontal expansion to -0.2 (optional - this is a bad idea for some prints with thin walls on the bottom layer) All line widths to 0.4 wall thickness 1.2 top/bottom thickness 1.2 walls 3 horizontal expansion -0.03 Also in CAD make vertical holes .4 to .5mm larger than desired hole size (or drill them out after printing).

Please show photos of the problem.

I found how to do it but Ultimaker asked me not to post the solution on the forum. You can easily brick the machine if you make a small mistake and to unbrick it you have to remove the bottom cover and that violates the warranty and there are deadly voltages exposed under the bottom cover. So on one hand it's very dangerous. On the other hand it's pretty easy to do. Anyway direct message me if you are brave and willing to take the risks. More details: you have to modify a json file on the printer and if there is a syntax error the boot sequence fails *before* ssh daemon is running. And then there is no way to ssh back to the printer to fix the typo. So it's bricked. To unbrick you need physical access to the linux computer. If you take the bottom cover off there are 2 ways to recover the machine. But if you take the bottom cover off there are high AC voltages that can easily kill you. But you need power on to boot the linux computer and fix it. So... dangerous. Ultimaker doesn't want you to die. Neither do I. So you have to take the risks seriously.

Sorry about this calinb - I'll message Sander directly. Did you have a password less than 6 characters? I know that was a problem for people with short passwords.

I usually call that "bubbling" on the top of your prints in the photos "pillowing". That is a symptom of not enough cooling (not enough fan) (which is kind of rare with ABS). So for the pillowing you need to either lower the air temp (I usually print ABS in 35C-40C air) or you need to increase the fan. What kind of printer is this as on the UM3 and the S5, 50% fan is the same as 100%. They tend not to slow down until around 10% so anything above 10% is the same as 100%. On the UM2 the fan at 50% is around half power and half the cooling. The elephants foot in your photo isn't just the bottom layer. It's many layers. I'm not sure what to do there. Maybe a different formulation of ABS. You could lower the bed temp to 90C but then parts won't stick as well (warping issues). Seriously consider making the reverse curve in your cad models. I know it's a pain but it's a solution that will work quite well. The basic problem is that the liquid ABS is acting like snot - like a liquid rubber band - it cools rapidly so it's already stretched tight within milliseconds and you are stretching it around a tight radius so it pulls inwards. As you get farther from the heat of the bed the layers below are stronger and they can resist better. Printing the inner shell before outer sometimes helps. This is the default though so you are probably already doing that. Bringing the fan up to speed sooner helps also. by default I think it takes 5 layers to get up to requested fan speed. So it's basically a temperature issue.

Nominally, Z=0 is supposed to be when the nozzle touches the glass. When you calibrate with the calibration card, the printer knows the thickness of the card. For example if the card is 0.1mm thick then it can set the height to 0.1 when you calibrate such that when the nozzle touches the glass Z=0. But that's not exactly what it does - it sets Z somewhere inbetween 0 and 1 such that the first layer gets squished slightly. If the first layer is 0.3mm thick Cura will absolutely, definitely set the Z to 0.3mm when printing that initial layer. But because the calibration cheats slightly it will hopefully be closer to 0.2mm above the glass.

The last meter of PLA on a spool is often brittle - particularly if it was left in the bowden overnight. Just break the brittle part off and throw it away. To get the filament out of the core it's easiest to just push it through while at 200C with another piece of filament (easier to go forwards than back). Alternatively you can heat a small exacto blade with a flame and then quickly slice off the filament just above the "trumpet" part of the core and now you can slide the core out. But then you still probably want to push the rest through anyway.

This is a common problem. It's almost always the power brick. If the brick senses that you used too much power it shuts off. But only for about 1/4 second and then power comes back on. This appears to be a plain old reboot but is really a power off/on very fast. If this printer is less than a year old I would try to get a free one from your supplier. If not you can just buy the power brick. Until you get the new brick you can avoid using the bed and instead use a cold bed and blue tape washed with isopropyl alcohol. Your printer should have come with blue tape for this purpose. Alternatively you can use the power budget feature in tinker marlin which is a fantastic alternative firmware for um2+ extended. You can download it here (you want the 5th one down of course): https://github.com/TinkerGnome/Ultimaker2Marlin/releases/ Go into power budget. I believe for normal printer you want: budget 180W bed 150W nozzle 30W With the above settings the budget will never limit power. so then you just lower the budget a bit: budget 160W bed 150W nozzle 30W That should be plenty to avoid tripping the power brick.

Wow. You are the second person today with this complaint. A solution is here (follow link). If you have further questions please post on that thread.

Oh one more thing - even though it looks bad while printing - it usually comes out fine in the end. if your problem is not exactly that you have raised edges but that the raised edges cause the part to come loose well then that's a completely different issue. I talk about many fixes for this. I have done prints where you hear the head hit the print ("BAM!") but the print stays on. I can pick up my whole printer by the tiny UM robot print. How to get parts to stick real well is a long subject hence the 15 minute video - I know it's a long video but it explains so much!