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tomnagel

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Everything posted by tomnagel

  1. tomnagel

    PVA not sticking on glass

    I recommend not to use just any glue stick, but the one supplied by Ultimaker. All glue sticks are not created equal. A lot of effort was put into testing, and the Uhu sticks came out best. I’m not saying other sticks don’t work as well, but i’m Sure there are other glue sticks who definitely perform worse.
  2. tomnagel

    Changing nozzles 5S printcore

    have you tried this? https://ultimaker.com/en/resources/23132-clean-the-print-cores I have yet to see the first case where disassembly is necessary.
  3. tomnagel

    Issue with PVA

    I don't think so. The printers were operated normally, and there was a cooldown between printjobs. I don't think that a pause of a day between prints can cause issues other than PVA taking up moisture. PVA should print reliably, this is tested very thouroughly for years now. If not, let's find out why not. There enough people here who can help, and your reseller should be able to help you as well. Start with a clean BB nozzle, start with dry PVA filament, use Ultimaker filament, use Ultimaker Cura without changing printing parameters. If that does not work, please post pictures of what goes wrong.
  4. tomnagel

    Issue with PVA

    Under normal circumstances, it is absolutely not necessary to clean your BB nozzle every few days. We've done 2000h tests on 20 printers, with varying cleaning intervals. Our advice is to clean the BB nozzle after 400h of printing (hot and cold pulls). But even the few printers that printed the full 2000h without cleaning still printed fine. However, cleaning is very important after incidents like empty spool, or entangled filament or any other issue that keeps the BB nozzle hot without any material flow. The PVA then burns in the nozzle, and the nozzle will clog. (a print where there is a very small amount of PVA on each layer could also cause this) Of course this was all tested with Ultimaker PVA. Your mileage with other brands may vary. And @kmanstudios is right: keep your PVA dry.
  5. tomnagel

    How to calibrate X,Y and Z-STEPS?

    Dimensional accuracy is a difficult subject. There are many many causes for inaccuracy. Some causes depend on temperature, some on the printing process parameters, some are in the mechanical tolerances on parts etc. It is a topic that is being addressed within R&D, but I realise that does not help you now. I would not advise to adjust the scaling of X Y and Z. That is too big of a simplification, and afterwards when you print objects with other dimensions your calibration will not work, and possibly make things worse. My own experience is that often the inaccuracies are pretty reproducible. A 4 or 5mm big hole prints always 0.25mm smaller than in CAD. So I compensate for that in CAD. You say you have measured inaccuracies up to 1.5mm. That is pretty extreme, and indeed can make parts unusable. Can you share an example of that? An STL and actual measurements, and/or a photo?
  6. I believe that when no material is set for an extruder, the nozzle stays cold during the active leveling. But you should know that it is heated to flatten possible plastic remains below the nozzle. If those plastic remains are cold and hard, the outcome of the active leveling procedure will get an offset, causing the nozzle to be too high during printing.
  7. So the problem stayed with the same printer, after you switched the power supplies of 2 printers? And you are using original Ultimaker Print Cores? Than I think you should contact your reseller. Your problem reproduces and it seems like a heater is out of specification, causing the overloaded power supply.
  8. Temperatures to get good adhesion are about 10 degrees higher for aluminium than for glass. For example, PC has a bed temperature of 120°C with alu. UM2/3 cannot reach those temperatures because of power supply limitations.
  9. tomnagel

    Ultimaker question | help us help you!

    Hi gr5, An outer diameter of the spool (G) of 102mm? You mean 201mm?
  10. tomnagel

    "Big" blob and huge retraction UM3 after abort

    @cjs Sorry for going off-topic, but did you change the (material of) your bowden tubes? They look white instead of semi-transparent.
  11. @The_Rob did this error occur during printing, or somewhere in the warm-up phase? I assume it is the latter. You can then maybe avoid your power consumption problems by first manually pre-heating your printbed. When it is hot, it consumes less power since the electrical resistance of the copper traces of the bed heater has gone up.
  12. tomnagel

    Ultimaker 3 Print Hood falling

    your fan bracket not closing properly might also be related to your problems with active leveling (other thread). The measurement pcb is located in this bracket, and when it moves during leveling, this will influence the results.
  13. tomnagel

    Clogged BB Core

    temperatures used to be in those help articles. Maybe they took those out because the printer takes care of that when you follow the built in procedure (UM3 only) (printer also moves the print head into one of the corners, so you can't forget that as well) (edit: I didn't see the responses above)
  14. tomnagel

    Clogged BB Core

    Hi @pfordmedia 35 degrees for a cold pull is too low. The material is much too hard to pull out, and will snap like you described. Please follow the instructions on this webpage.
  15. tomnagel

    Clogged BB Core

    Please don't put words in my mouth. I mean my statement literally, and I don't mean to imply anything else. Users following my advice profit from thorough testing that takes place within Ultimaker. Users who make other choices have to find out stuff for themselves.
  16. tomnagel

    Clogged BB Core

    Disassembly of your print core is not advised and never necessary. With hot pulls and cold pulls it is *always* possible to get your print core going again. Cold pulling with polycarbonate works extra good if you have that. please believe me: PVA printing is reliable on your UM3, if you stick to Cura profiles, UM material and keep ambient relative humidity below 50%.
  17. That is not so weird if you realise that the electrical resistance of copper is dependent on the temperature (resistance increases when it gets hot). So if the heaterplate (of which the tracks are copper) warms up, the power consumption drops.
  18. tomnagel

    Single Nozzle Print Setup?

    True that. Switching between different materials may mean extra cleaning although my personal experience is that it is not needed. Some flushing suffices. pro-tip: there is now a timeout on the last bit of the filament loading procedure. After you have confirmed the filament is fed into the feeder, the printer will feed the filament to the printhead and extrude slowly for a minute or so. You can leave the printer unattended, and use this time-out as a flushing procedure. use the latest firmware, because earlier versions do not have this time-out.
  19. tomnagel

    Single Nozzle Print Setup?

    Both nozzles are heated before active levelling. This is because we need to squish possible plastic remains during the first probe with each nozzle. @Bossler, you mention "print head cleaning seems to be quite often needed with the UM3". What do you call often? Internal tests have here have shown that print cores do not clog even when not cleaned for 2000h print hours, although there is a slight build-up of yuck inside the melt channel. That is why we advise to clean the BB core every 400h. I think that is pretty reasonable.
  20. The sensor that we have implemented is very light weight and hardly takes any space. The measurement accuracy of the complete system is very high, reproducibility is below 10 microns. Next to that, due to the smart algorithms that we created, we measure the distance between glass and tip of the nozzle. A laser might reach 1 micron accuracy, but a laser does not measure between the tip of the nozzle and the glass plate, so you introduce extra errors. And it will probably be heavier and a lot more expensive.
  21. tomnagel

    PLA & PVA... Print-Questions...

    Nice print @kmanstudios! Beautiful.
  22. tomnagel

    PLA & PVA... Print-Questions...

    Have you tried printing with all default settings? In the office here, I never see anyone using an ooze shield. I guess because it's not optimal. The default profiles work very good for Ultimaker hardware and materials, for most models at least.
  23. tomnagel

    Filament monitor for UM3/UM3E

    It is not so simple. The 4 wires connect to an SPI port in the printer. You cannot connect a simple on/off sensor, and get the behaviour (pause the printer) you want. You will have to create a simple IO connection on the Olimex board, and change the firmware. I have experience with electronics, and did some hobby projects with Arduino, but I would not try such a thing. The UM3 is too complex on the inside.
  24. tomnagel

    Clogged BB Core

    Glad you solved the clog. But still interesting to know the root cause. The BB core should not clog, also not after many days of printing. However, a minimum flow is needed. How much PVA was in the layers before it failed? If it has to heat up the nozzle tp print a tiny bit of PVA every layer, it could burn and clog. This is however very rare. Another option (makes more sense) is that there was another reason that there was no flow, for instance entanglement of the filament. Your clog was then the consequence of this. Did you use Cura for slicing? Cura takes care that the not-used nozzle is lowered in temperature.
  25. tomnagel

    print head thermal stability (or not!)

    Are you sure this graph is from during printing? Or is this graph from during Active levelling? Behaviour during Active leveling is different on purpose.
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