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UM2 -> UM2+ Severe Issues


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Posted · UM2 -> UM2+ Severe Issues

My school has 15 UM2 printers that have since 2015, and have been mostly printing continuously during the fall and spring semesters. Over time, they have become very difficult to fix, often clogging after every single print. We have bought new nozzles, Teflon couplers, and have maintained them well over the years but they still have deteriorated very badly. In February of this year, we decided to buy 10 UM2+ upgrade kits to try and solve all of the problems. Since it included a new feeder, axles and entire head, we figured that it would basically change all of the parts which actually do the printing to be brand new, and refresh the entire printer.


However, now that we are back at the university since the pandemic, we have found that they are having all kinds of troubles once again! Bowden tubes pop out mid print, clogging, and even overflowing (like the attached photo).


Everything is brand new, so we have absolutely no idea what it could be that is causing problems. We followed the installation guide and everything fit great, but are running into the same problems as before almost immediately after installation.


Could the air movement/temperature of the room ruin these printers?


Could it be a manufacturing error on all of the upgrade kits? Even if not, is there any way to get a refund on these? Because they did not help at all...


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    Posted · UM2 -> UM2+ Severe Issues

    Wow!  You are having a lot of problems.


    Please stick with it.  These UM2 series printers are a very good product.  I use my UM2 printers the most.


    I guess we need more specific information.  Let's take the problems one at a time.


    The problem above - it's hard to diagnose with just one photo and it could be something leaking around the heater block but I think it's a head flood caused by a part coming loose:

    What happens is at some point while printing the part it is wider than tall and then comes loose from the bed.  Then it gets dragged around the bed like a hockey puck and the filament is still spurting into the print.  If you don't notice and an hour or more goes by you get something just like the photo.  To fix, heat the nozzle 200C and walk away for 20 minutes.  Come back with a heat gun or hair dryer and some metal tools (like needle nose pliers) and pick off bits at a time.  Shouldn't take more than 20 minutes.  You don't need to get it all.  Be VERY careful around the wiring - consider just leaving it around the wiring.


    Do you have parts coming loose often?  You need as a minimum to wash all your glass beds.  They get finger oils on them and they get dust.  I wash my glass about once per month.  I show how I do this - it's a few steps - in the video below.  If you have parts coming loose a lot you probably aren't leveling properly.  Please watch my video if you have corners lifting/warping or parts coming loose - this will solve many of your issues (but not all):


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    Posted · UM2 -> UM2+ Severe Issues

    Okay now as far as bowden tubes popping off - I guess I could use more information.  This should not happen.  Once it happens you should cut 1mm or so off the end of the bowden because inside the collet there are 4 blades that hold the bowden in place - they dig into the bowden.  If you force the bowden out it will scrape the bowden and remove the outer layer and next time it's even easier to happen.  Inspect the 4 blades and get new collets if they are damaged (I sell them very cheap if you are in USA).  Then cut off about 2mm off the end of the bowden.


    Bowdens should not come out.  You can normally pick up the machine by the bowden and swing it around your head.  They should not come out.  It means the pressure in the bowden is extreme.  Maybe you are printing too fast (e.g. layers too thick)  At least you know your feeder is working well if the bowden is coming out, lol.


    Try to not go over 5 cubic mm/sec (multiply line width X layer height X print speed (check all speeds including infill speeds) and keep that at or below 5 (for 0.4 nozzle double that for 0.6 and double again for 0.8 nozzle).  The printer tops out around 10 or 15.  Best to keep things well below the limit.

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    • 2 weeks later...
    Posted · UM2 -> UM2+ Severe Issues

    Hey, thanks for the reply.


    There does not seem to be any pieces loose or coming apart. The error shown in that photo is directly after we installed the Ultimaker 2+ upgrade, where everything would have been assembled by Ultimaker, not us. The problem doesn't seem like it is specifically with the glass beds, because we haven't really had any issues with build plate adhesion or corners lifting up, as we also wash the buildplates (not as frequent as once per month though).


    We will try cutting the bowden tube down 1mm, and returning back with results, but I'm sorry I don't a have a picture right now to show. It was very odd because the bowden tube popped out on the backside of the printer, where it comes out of the feeder. Does taking the bowden tube out frequently also wear on the tube's ends? I mean carefully removing the collet like normal, not forcing it out.


    I also calculated that with our normal setting we are printing at about 10 cubic mm/sec! (with a 0.4 nozzle). I wonder if we just tried to speed up the printers far too much..


    I will get back to you about the bowden tube, but I am still not sure how the head overflowed like that. Maybe it was also a result of our high print speed?


    Thanks so much!

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