waizman

Thanks! Any way to use the heat break feature without having this threaded part being 1.75mm itself? You only use 2.85mm?

Some more updates - I figured out that my problem was with the 1st feeder original lever. It was not puttying enough pressure on the filament or something. Which is weird because the 2nd one is great. As previously mentioned - The 2nd feeder have a "Lazy Lever" (UM2+ Lazy Lever by sneakypoo - Thingiverse) and the 1st one had an Original one. This is because when trying to change the 1st feeder's lever to a lazy one, it failed to print almost every time. Something got me to suspect the lever again and I printed this one (1.75MM CONDUCTIVE FILAMENT FEEDER for ULTIMAKER by osdoyi - Thingiverse) instead. And it now works PERFECTLY! Three issues though - The filament is VERY hard to insert into the feeder. Almost no play with the new angle, even when on lowest pressure setting. There's no more 2.85mm option as the 1.75mm barely goes in now. The wedges (WedgeBot/TheWedge) no longer work. So I sent a message to the Lazy Lever designer asking for a mod that will make the lever more like the other one but with the lazy part. Unfortunately I'm no great modeler and don't know how to do it myself. So long story short - now it prints great and FAST! With all the friction in the world holding the filament tight, I can now print at speeds of 150-200mm @ 0.2 layer height. Before 70-80 was the max.

Sorry for the delayed reply, I was out of town and far from the printer and PC. As for the heat break you've mentioned - where is it? That's the area just before the nozzle? I got so many problems there, So now I'm just using a longer tube and push it all the way inside the nozzle. Tried 1.75mm nozzles too but the 3mm are somehow better... Added some pics to show you how I converted the printcore. It's orange because the original black parts got broken and I found that it is not getting too warm so it is now printed in CPE and works great. And the tube got replaced with a new one, don't worry 😉

I inserted a 3OD/2ID to the printcore from the top all the way to the nozzle. Tried a few sections of PTFE tube but the transitions between them always caused a jam. So took it all apart, removed any PTFE tube that was there, and just put a single one from top to bottom. The extruders and bowden got no mod. I'm testing a tube-within-a-tube now (4OD/2ID inside a 6OD/4ID tube). NEVERRRRRRRR It's just so random to have a specific diameter just for Ultimaker... It's a pain in the a$$ to get, and it's always very basic colors and types. Here in Israel at least. Tried 1.75mm nozzles and heatsinks for the printcore - they all work worse then the original 3mm stuff. So a simple 1.75mm conversion it is! Both sides are converted btw. 2nd extruder actually work better than the 1st. I agree.

Thanks for your answers. Makes sense! Dunno. I was the only thing I saw changing while the print failed. Needs more testing. The purple filament is pretty new. Maybe a week since I opened it. I live in a pretty dry place (Eilat) and the humidity level usually stay under 30%. It is generic, but the other colors from the same brand work great. During prints it doesn't break and no cracks are visible. It's not "crunchy" either and cannot be broken by bending it. Very weird filament... I don't. I use the original 6.35mm bowden tubes. BTW I tried replacing them with new ones and found out mine were too small (6mm) 🙈 Also tried to insert a 3OD/2ID bowden in the original one and it got sucked in by the retractions as you mentioned. I was considering gluing it inside the original one using superglue, but I don't know if it will give me any improvements and I don't wanna ruin the bowden... Any thoughts?

As I said, I tested 3 printcores and they all act similarly... Some of them are already re-programed (BB to AA, of course I changed the nozzle to match) as instructed here: Print core BB-0.4 wrongly recognized as a AA-0.8 - Improve your 3D prints - UltiMaker Community of 3D Printing Experts The 700c spike is momentarily and as far as I recall it happens on all 3 printcores. So I think it's not them. I will probably disassemble the whole head tomorrow and make sure everything is tight. --- So I changed the purple filament I was using and the print was successful. Not the best (stringing-wise mostly), but it was a 5-YEAR-OLD filament I had laying around. Photos attached. It's a 56 minute Benchy BTW. Not bad. Some things I've noticed: - The graph looks much better to me, overall it's much more stable. - Retractions cause the small temp spikes in the heater (Brown) line. - There is a steady decline in the Brown line trend. - Orange temp sensor line is rock solid. - The previous two points mean the heating block steadily needs less energy to keep the temperature? - The 700c spike is momentary but it causes the heater to drop to ~50c and then overshoot the Orange sensor line. Not a big deal probably but if it is fixable - why not. Now what I don't understand is WTF is up with the purple filament? It's new and shouldn't perform worse than a 5 y/o filament that got no care at all... My primary goal is to make the system failproof - maximum relatability and quality. Once that have been achieved - find the maximum speeds possible while maintaining reliability and quality.

Thanks for your answer. I am VERY proficient in disassembling things, don't worry 😉 I have 6 print cores and I've tried 3 different ones in my fixing attempt - all behave the same. I don't like that 700c spike either, but I don't know how to fix it. I also saw it was very common in other people's graphs, so I thought it was not a big deal... Tested the resistance in the back chip connector as well - Heater is ~25ohms, sensor is ~110ohms. Looks fine and same as other people. Also unscrewed the screw between the printcores 1/4 turn as mentioned here: Print core is taking too long to heat up - UltiMaker 3D printers - UltiMaker Community of 3D Printing Experts No change. Tested the filament location and holder - no change. I'm now testing another filament from another brand. I have a feeling it's the purple one that's acting weird... Even though it doesn't make sense... 😄

Answered in red font: Also did a "heater test" in the maintenance menu - got these results: I've noticed extruder 2 heats up faster then 1... Thanks ❤️

Some more info: - This happens almost always on Extruder 1 (Left one). Extruder 2 works well with the same exact settings or only different by the temperature setting (210c). - The temperature in the printer lcd is always correct (same as set in Cura). - Tried 2-3 printcores on Extruder 1 and nothing changed. - issue happens whether Extruder 2 is disabled or enabled in Cura. - Filament is Generic PLA+ (Purple). Also have eSun PLA+ and Ultimaker CPE (PETG) to test with. - It seems the non-printing printcore never drops below 40-45c. Added more images - temperature graph and its corresponding print (3DBenchy trimmed to the problematic area).

Hi! I have an UM3, converted to accept 1.75mm filament (PTFE tubes in the printcore, nothing more was needed) and I've noticed some of my prints failed with no apparent reason so i decided to pinpoint the problem. I've managed to improve the issue by reducing the "Minimum Extrusion Distance Window" to 3mm, and the "Max Retraction Count" to 10, as well as printing with higher (230c) temp. Other settings - Speed 80mm/s, nozzle 0.4mm, layer height 0.15mm (= Flow 4.8mm^3/s, I try to not go over 5.6mm^3/s). Now it seems my prints mainly fail due to temperature drops - by looking the temp graph, I see that sometimes the nozzle temp drops below 190c and that's when I get a lot of underexcretions and fails. Why? I don't know... I believe it is caused by the fact that it takes some time to heat up the fresh filament and the heater is just not fast enough. I've noticed it tend to happen in areas with more retractions like the top of the steering wheel in 3DBenchy (photo attached). Any advice on how to better retain the chosen temperature? Latest firmware (5.3) and Cura (5.6.0) versions. Thanks in advance