gr5

If you print with SD card you can save it in "ultigcode" mode which lets the *printer* set the temperature of the filement. If you print with USB cable you MUST use "reprap non-volumetric" mode (this is all in cura machine settings). You should be able to do it either way.

When selecting PLA Flex - hover over that for a while and it will cycle through all the settings - make sure it's "240". Also after you select PLA Flex, try doing MOVE MATERIAL and see what the goal temperature is for that step also. Make sure that is *also* 240. Then start the print, etc. Thanks for helping debug this issue @alecuif

Ah. Interesting. Did you get that @alecuif? Daid thinks you did something like this: 1) Created PLA Flex with same settings as PLA. 2) Edited PLA Flex on the SD card again and imported again (at this point you still have old PLA Flex settings) 3) Started a print and chose CONTINUE to the question above 4) Ended up with the *old* PLA Flex settings In other words Daid doesn't believe that CONTINUE goes back to PLA. Could you test this one more time? Someone else needs to test for this bug. My only UM2+ has a different firmware (tinker marlin).

If you skip the alcohol cleaning step then parts stick less-well. Which of the united states are you in Ronan?

Okay. I posted it over on github. We'll see what the developers say: https://github.com/Ultimaker/Ultimaker2Marlin/issues/106

I agree. But apparently you don't like to squish your bottom layer as much as I do - so that's one issue (even just raising the bed 0.01mm will help - yes .01mm not .1mm). I don't blame you - for dimensionally perfect parts I do the same thing - I don't squish the bottom layer at all and have the same issue - parts occasionally warp off the bed. Also you don't like brim. As for "wall-cave-in" the only thing I can imagine that changed is that your air temp or your bed temp (and hence air temp) is warmer than it was when things were working fine. For some reason the air is warmer than before - maybe a fan 50 feet away used to be pointing at the printer but now points a different direction - it could be many things that affect temperature and airflow.

This is probably a temporary bug that will get fixed in the next release (and works fine in the previous release I think - 15.04.4 - not sure how far back you have to go for this "feature" not to exist).

So since your are in USA, know that if you buy anything from my store you will get a free steel nozzle cleaner that fits in in nozzles .35mm and larger: gr5.org/store/

The circuit that turns the fan on at 40C appears to be purely analog. It doesn't turn it on instantly but gradually between 38C and 42C. I suspect a transistor. This would agree with your measurement of 2.5V at 25C. however if at 50C the 3rd fan still does not spin then I would look over the schematic. Unfortunately the newer schematic with the fan circuit is in schdoc format (altium?) and the Altium software has a free trial but is not free. Too much trouble for me to convert to an image at this point. It's fine to just short the 2.5V line directly to 5V and let the fan be always on. That's how my (older) UM2 works. Although the older UM2 also has a much quieter fan. https://github.com/Ultimaker/Ultimaker2/tree/master/1546%20ultimainboard%20V2.1.4

HTPLA 120C! https://www.proto-pasta.com/products/high-temp-pla-v2-0

Ah! I suspect this is the secret sauce. Sanding creates a rougher surface hence more surface area to stick to.

Oh - and if slowing it down fixes the problem and you never used to have the problem (as you say) and you didn't slice with a newer version of cura then the problem is most likely related to the nozzle anyway and just has some buildup which gives it extra pressure and printing fast (higher pressures) is what tends to cause these bumpouts. So instead of using a larger nozzle (I strongly recommend that for this part!) you could just burn out the nozzle to ash and maybe also soak it in acetone overnight and maybe also do a few cold pulls and maybe scrape the nozzle a little with a nozzle cleaning tool (what country do you live in as where to get a good nozzle cleaning tool varies by country - please update your profile). Or just buy a new .4mm nozzle from 3dsolex.

Try printing at half speed. It sounds like you are printing lots of these and want to print them fast but just try it. Actually try 20mm/sec just to see if this fixes the problem. Most of the time cutting the speed in half will get rid of these bumps. If you printed multiple of these parts on the same print bed then it could be a leaking/stringing issue but that's not what it looks like. Also check and make sure the infill speed is the same as the print speed. If you want to print this faster, use a .8mm or 1mm nozzle - because there are no sharp corners you will loose no quality and you can print in half the time with the same layer height and print speed and you can probably speed it back up again (less pressure build up in the nozzle with larger nozzle).

When you updated the firmware from Cura you must have selected UM2 instead of UM2+. They go opposite directions so you have to select the right one. Even better I recommend the um2+ fimrware from here: https://github.com/TinkerGnome/Ultimaker2Marlin/releases

When you updated the firmware from Cura you must have selected UM2 instead of UM2+. They go opposite directions so you have to select the right one. Even better I recommend the um2+ fimrware from here: https://github.com/TinkerGnome/Ultimaker2Marlin/releases

A year or two ago they changed the circuit board it so the fan now only comes on when the nozzle is above 40C.

GOING TO SAN FRANCISCO! Yay! Makerfaire Bay Area! If anyone on the forums lives in the Bay area please come visit me at Makerfaire. Message me in private and I'll give you a way to reach me during Makerfaire. I love meeting people from the forums. I think Sander might be there, right? And I hear Iris will be there. I'll mostly be at the booth but occasionally won't and if you message me I'll hurry back to the booth. My wife and kids are going to this also - their first Makerfaire (although mostly they want to meet with friends - bleh - how can friends compete with giant steel fire breathing Octopus?).

It depends what you care about. If you want beautiful prints then here's the advantages of UMO,UM2,UM2+ Light weight head allows very very high acceleration and high "jerk". UM printers can do 9000 mm^2/sec (default to 5000) and most printers with feeder on the head do 1000mm^2/sec. Why does this matter? It's very difficult to speed up and slow down the flow of plastic coming out of the head. So everytime you slow down (for example) to print a corner on a cube it overextrudes the corner then as it accelerates out it underextrudes the wall because there is a delay between feeding and the pressure that accumulates in the nozzle and when the filament comes out. The delay is maybe only 20-1000 milliseconds but it's a problem. With high "jerk" (UMO through UM2+ use 20mm/sec) the print head never completely slows down on a corner. "jerk" in marlin is defined as instantaneous speed changes in the XY servos (true jerk is totally different - the derivative of acceleration). Fans. For PLA (not higher glass temp plastics like nylon or ABS but for pla) fans are super critical - you want to cool it very fast. UM2 is much better than UMO regarding fans and the quality is slightly better. UM2+ supposedly is even better but I can't tell the difference (haven't done any tests on bridging or overhangs with my UM2+ versus UM2). Many people have printed there own UMO fan shroud getting the quality just as good as UM2 or UM2+. UMO is still an excellent printer. UM just keeps improving it every year. As far as your original question - printing temp - please realize that the temp at the tip of the nozzle is different than where the temp sensor is so different manufacturers will tell you to print at different temps which can vary 30C. 210C is a good typical printing temp for all UM printers but people print PLA on UM printers from 180C to 240C. At 180C it's like toothpaste and lays down like wet cement - very good quality - stays where you put it. At 240C it flows like honey (you can print 6x faster) but the PLA doesn't stay exactly where you put it.

Oh - one more thing - for large prints - say 150mm wide or longer on one axis - I do an extra good job because it's that much more critical (much more powerful warping/lifting forces). So I will usually completely wash the glass and apply a fresh coat before any print longer than 150mm. Such as a quadcopter plate or arm.

At least once per month I take the glass out and wash in the sink with soap and water to get all the accumulated dust off the top. Even if I only did 1 print that month. I often go 10 prints before re-wetting the glue. I don't usually reapply glue unless it's because I washed the glass. To re-wet the PVA I take a small paintbrush soak it in water, then spread it around on the glass mixing the water into the PVA for about 10 seconds then turn the bed heat on and dry again and ready to go within 5 minutes. Everytime I rewet the glass gets ugly around the edges so after doing that 2 or 3 times I decide it's too ugly and wash it clean again. My favorite PVA is elmers wood glue mixed 1 part glue, 10 to 20 parts water. Spread with paint brush. I keep a jar of this mixture and a clean paint brush in the same room as my printers.

Let me know what version of firmware you have and I'll post this bug over on github with a link to this topic.

So there you go - delete the "MTYPE" from you gcode might be a reasonable fix for now until they get this firmware bug fixed. Or go with a slightly older firmware. You can tell which version of firmware you have on the printer by going through the menus - start by choosing ADVANCED and look around from there. Each version of Cura comes with a Marlin. You can update Marlin by connecting a USB cable to your printer and there are options in Cura for updating the firmware. Certain settings are preserved if possible (leveling position, hours printer has been used, material settings, motion settings) but sometimes updating Marlin does a "factory reset" because the settings are now in a new location in memory. "Factory reset" sets most those to defaults forcing you to relevel and recreate your material settings.

Chinese UM clones tend to suck. Really really suck - things don't fit - electronics have subtle problems - more things don't fit... Like waste 100 hours (like 6 months) of your life suck. Just warning you. Better to build a UMO from scratch than buy a chinese clone.

1) Let the tape rip and make a mess. 2) Place the print in a pan with a very thin layer/puddle of isopropyl alcohol for 5 minutes. Then the tape almost falls off. 3) Re tape your bed after each print. Now you see why glass and PVA is an improvement for most people. I have no idea why you have so much wall-cave-in. I'm thinking your heated bed is like 20C hotter than normal and the temp sensor is way off. Do you have an independent method of measuring bed temp such as an IR temperature gun?

I'm still using cura 15.04.4. Hey @nallath! Do you know about this new feature in Marlin?? Look at the photo just above.