kc-li

Hi, thanks for the reply. I've done the diagnostics (previously) to test the capacitive sensor (check the wires, reseat cables, no ESD interferences etc etc) (and I've also replaced it with a brand new one to check if that was the issue and it did not fix it). I always get a "offset probe not working properly". I tried running the diagnostic tool for the sensor as well under maintenance and it would fail (but I can't remember the error message). What's worse really is often the nozzle doesn't even get anywhere near the build plate (literally around 20 mm away) and it would detect that as failure and then switch printheads try something again, fail and then give me the offset probe error. I'm a bit reluctant to upgrade back to 5.28 for now since now that I'm downgraded back to 4.33.. it works fine again at the specific buildplate height I've worked out. I am fairly confident the capacitive sensor is working since I've tried it with 3 separate ones and they all do not work on the new update. My UM3 is relatively "old" and the capacitive sensor board (even the new one I got) was from a a year or two back so I'm not sure if there has been an upgraded version since then? Even the old active levelling was very sensitive already though. Literally if I have a tiny piece of filament residue on the printhead, that would be enough for me to get a "offset greater than expected difference" error and if I have the screws on the buildplate even off by more than 1 turn on any of the 3, it would not active level. At the moment though, (on firmware 4.33) the printer works great and the active leveling is accurate. Lastly, I do keep it on "never" since I don't want it to autolevel everytime and the chance of it encountering a "offset greater than expected difference" error. Does that make a difference?

Hey, thanks for the reply and bringing the thread to my attention. I did have a read of that thread but not anyone has really given much specifics to the autolevelling but I'm glad it is an issue that has been raised. I was thinking maybe there would be an official announcement not to update this "stable" release if it is causing so many issues.

So based on the lack of reply I guess my issue is isolated? Strange, I've encountered it on both UM3 I have access 😕

I'm writing this post as a warning to others and to also get a gauge of whether this is an issue in the community. So I have UM3 extended and recently I did the auto update from firmware 4.33 to 5.28. Immediately after, the autolevelling stop working. It actually took me awhile to figure out why it stopped working. Before I get into it, I want to mention, the autolevelling system on the UM3 has always been very very sensitive, that is, it will only work if I have the screws on the build plate at a particular "depth". This is not just for one machine, I've tested it on 2 and if I don't have the screws at the exact position the machine likes it, it will either stop short of touching the build plate during autolevelling, or start smashing right into the glass until it reaches the predefined "offset" (which is something like 15 mm?). Also, the movement of the build plate in manual levelling is very strange in the updated firmware. It's not smooth and moves a little sporadically. Anyways, back to my problem, so after the update, I notice the autolevelling was completely different. For one, it started indicating that it was heating up the build plate and printcore (something it didn't do on 4.33) and it took a heck of a lot longer. Afterwards, the buildplate would move up half way, stop, then the head moves in, build plate moves up again before starting the autolevelling. I figured this was an update to the autolevelling system? In the past, it would bring the buildplate up in one go, then start the autolevelling on the left nozzle followed by the right. Now no matter how I configured the settings, I would always get a autolevelling sensor fail or offset probe not working properly. I tried everything including changing the capacitor sensor with a spare I had (that worked!) and nothing worked. Finally, I decided to muck around with the internal json settings and trying to decrease the tolerance of the offset but I accidentally bricked the machine somehow. Alright, no biggy, reflash the firmware with the recovery image and in a fortunate delight, also reverted back the firmware version to 4.33. Everything worked fine after that! Autolevelling is back (again with the very tight screw settings but functional it is!). So, my question is, browsing through the forum, I have not seen any complaints about this latest 5.28 "stable" firmware update nor does there seem to be any official acknowledgement of the issue as far as I can tell? So am I alone with this issue? Also, is the autolevelling suppose to be so difficult to configure? Couldn't they at least lower the tolerance of the offset distance between the two nozzles and allow the buildplate z distance from nozzle to be configured in a way the screws are not always screwed completely tight. I for one will be sticking to the old firmware indefinitely as it seems any future updates will only bring stability issues rather than fix them.

Is it only on one of the motors for you? Yes, well one direction, I think when it moves either x or y, it vibrates so hard that my whole machine moves. It hasn't significantly affected my print accuracy though, but I did notice with my UM2 I have to print at much higher than original temperatures to get the filament to not under extrude (probably a separate issue and have not bothered to diagnose it since I've been using the UM3 a lot more).

Thanks, will definitely check and secure all the connections tomorrow once I bring in my screw driver set. At the moment it's around 3 hours in and still printing, fingers cross it'll keep going while I sleep.

Now that you mention it, my UM2 does the exact same thing. It wasn't like this in the past hmm...

Hi everyone, So I've been printing with a UM3 extended a little under a year with little to no issues up to now. Recently, our department relocated to a new building and we hired professional movers to move the equipment. However, today after I setup the printer again to do a 18 hour print I started experiencing problems. Firstly, I did an active build plate leveling and it was not able to detect when to stop pushing the print head onto the build plate. I tried 3 times and each time it would keep pressing onto the build plate to the extent I shut it down in fear that it will cause permanent damage on the glass/print head. I manage to resolve this by doing a manual leveling first and then active leveling worked fine after (weird though I don't see why manual leveling would have fixed this if it worked fine prior?) So I started an 18 hour print but then about 30 minutes in I hit an error that said "detected movement outside of print volume..." and it stopped by itself. This is actually not the first time I've encountered this error, I had a same error about 200 print hours ago but it didn't appear again after I restarted the print. So I restarted the print again, and this time around 2 hours in, I encountered another error, this time it was a print head communication error ER18. Restarting the printer seem to resume normal function again, I checked if the printcores were being detected by the UM3 and it seems okay. I changed both print cores and have now started the print again. It is about 40 minutes in at the moment, it still seems to be okay. Having so many errors appear simultaneously after a move seems to indicate to me that either something was damaged during the move or something is loose? What do you guys think the problem could be? Should I contact my reseller if the current print fails too or what I some things I should try first before that. Some extra info: Using latest Cura version as well as up to date stable firmware version. Update: So last night the print didn't stop again but now my active leveling seem to have stop working even after manual leveling multiple times. It seems to have trouble detecting when to stop. About 10 attempts in, one of them did prompt an active sensor failure but didn't show up again later. Where exactly is the active leveling sensor? is it on the bed? Funny enough, if I remove the glass and try level on the metal surface directly it works! I was thinking this was a manual leveling issue with the z but i've manual leveled the glass bed multiple times. Update2: Okay, upon further inspection, I found a cable that broke off connected to the front fan that flips down to gain access to the printcores. The cable is labelled "sensor". I presume that is what is causing the issue here! Update3: Okay, sensor reattached and now active leveling seems to be working fine, yay!

Thanks for the info, will check it out!

So I'm looking to print something that needs to meet a certain strength requirement, namely it has to have to be relatively stiff. I have already tried the typical PLA, ABS and PETG materials but they're all not stiff enough for the purposes I was hoping. Is there any suggestions what materials I should look at and where I can potentially get them? Thanks in advance.

So I have a UM3 and I've noticed a consistent problem, especially with the PVA material, that is, during the initial extrusion of the filament, the initial knead of material tends to get dragged into the print instead of staying at the location it was extruded in. This happens with PLA as well but at a much rarer occurrence but pretty much happens every time with the PVA. The temp solution I've done to stop this from affecting/ruining the print is to wait for that stage to occur, have my tweezers ready to pull the knead of material away and make sure it doesn't get pulled in. I notice this happens because after the material is extruded, the nozzle moves "into the material extruded and then the hot nozzle sticks to the material and then it's pulled back into the top corner. I have a crappy video of this (link below, apologies for the vertical orientation). I wonder if it's possible to revert back to the way UM2 extrudes materials where it is done at a relatively high height so the material doesn't get pulled into the print. At the very least, maybe adjust the movement so it doesn't bump back into the material during the movement to the top right corner? Also, the PVA nozzle gets nasty real quick as you may notice because of the PVA that sticks to the side over time (is this normal?) and it's extremely hard to clean. I lost the silicone cover (and buying a new one) due to one of the previous attempts and the nozzle was completely clogged outside. Another issue I've been having is the glass plate seems to be quite warped. This results in me not being able to use the last 10 centimeters of the print area since the material cannot adhere on nicely and results in getting pulled off the glass plate after a few layers. I've tried active leveling and manual leveling but none of this seems to help. I have read in the past on the forum of other users experiencing similar issues with warp glass plates and they at the end sourced one locally to fix the issue. Should I contact the reseller to get a replacement? Thanks in advance

Sorry to dig up an old post but man, I followed the suggestion and used the sunon fan suggested above and man the difference was massive! I bought the UM2 about 6 months back and it arrived that noisy to begin with (I kinda thought that was just how it was meant to be). It was so noisy that you could hear it across the room with the doors closed and staying too long in the room made your ears ring. But after changing to this sunon fan, what a difference!, makes almost no noise that I'm having difficulty getting used to the peace.

Sorry for the late reply, thanks for the info, I'm located in NZ and I don't think there are any resellers close by where I am unfortunately. But if it does come to it, I will contact the support it seems. Thanks!

The website only seems to sell spare parts for the UMO. Can't seem to find where I can get spare belts once they've finally worn out. Thanks in advance.

Thanks for the response Guess I'll have to consider the other two options. I'm just trying to figure out how they manage to 3d print wax dental crowns commercially because the equipment exist (http://www.3ders.org/articles/20140514-stratasys-launches-two-highest-precision-wax-3d-printers-for-dental-industry.html) but as with many things in dentistry, the price is obscene (upwards $25k and you can only imagine the upkeep of the wax cost). The claimed resolution on theirs is 50 microns xyz. I guess they must have some secret to it. Thanks a lot again for all the responses!

Hmm, I've been doing a little more reading. Out of interest about the potential to use a smaller nozzle (browsing the forum a nozzle diameter of 0.2 mm appears to be possible although questionable, perhaps 1.75 mm filament would work better with a 0.2 mm diameter nozzle) Putting aside it's practicality I don't understand the bit gr5 referred to about requiring soldering and drilling to change the nozzle. I thought the nozzle bit was a simple screw design and nozzle replacement can be easily done by loosening the screws and unscrewing the nozzle ad popping in a new one with a different nozzle diameter? (there appears to be quite a few third party providers of such nozzle) At least this was what I made out of after looking at this small tutorial http://www.fablab-regensburg.de/wp-content/uploads/2014/04/Ultimaker-2-Nozzle.pdf Am I mistaken somewhere?

Thank you gr5 and Robert for your replies. This has been very helpful for me!

Thanks for you input , I too agree that the B9 or the Form1 are much more ideal options. Especailly the B9 since it has good resolution in all xyz dimensions. The one thing I have to also consider is cost however. I know the light cure resin comes a bit more expensive per kg compared to PLA. I'm also not sure if the resin is used 100 % without waste (or a certain amount has to be wasted per print. I'll do a bit more digging on that.

I have another question. Say I do go ahead and print a PLA crown design. How would the machine cope with the xy dimensions which is thinner than it can print. Does it try to do as good a job as possible or does it compensate by making the wall thickness comply with the inner or outer wall? (which one, this is quite important). For the latter, I wouldn't mind if it had to print a slightly thicker wall on the outside since it would be simple to manually adjust. (so in this situation we would have the crown fit well on a tooth preparation but there will be an overhang). The other situation would be it compensates inwards and the crown now doesn't fit on the tooth prep since the inner dimensions are now too small. I guess the short question is: does the machine take priority on getting the inner or outer dimensions correct if it's trying to print something thinner than it would allow.

Hmm, okay, thank you very much, I will look into those

Hello everyone, Firstly, thank you in advance for your contributions. I"ve been doing a lot of research on the potential to buy an ultimaker 2 to print some dental crowns for my research project. So far what I know is the layer resolution is 0.02 mm (20 microns) but what I would like to know is how well does this translate onto an edge. Basically what I want to print is something like this (cross sectional view) Think of the whole cast metal coping and porcelain as one structure for now. As you can see, as we get closer to the margin of the tooth, the edge finishes off quite sharply. The edge has to be quite sharp and accurate since marginal accuracy for dental restorations are quite important to reducing the likelihood for future caries to develop. The typical marginal accuracy requirement is about somewhere under <100 microns (0.1 mm). Do you think it's possible? If not, what is the typical knife edge dimensions one would expect from the ultimaker printer. (if I'm not explaining myself well enough, just try to imagine you're printing a plastic knife, how sharp would you expect that knife to be? Thanks!