veedee

I have the R17 version. I really ran out of possible improvements to make the machine work. I think it's a temperature issue, but I don't have the right equipment to calibrate it.

I actually do not think that the E3D hotend is the problem, because I use them on 10 other machine, where they work absolutely fine with higher extrusion rates. Also, printing PLA on an all metal hotend can be improved by seasoning the filament with a tiny wipe of vegetable oil. I think it has something to do with the temperatures on the sigma, which probably are not displayed correctly. Higher temperatures print way better on my sigma.

Nope sadly not. I have heavily modified the machine to try and make it work reliable. I added UMO style extruders with hobb goblin drivegears, E3D hotends with silicone socks, better hotend carriages with improved airflow, but sadly nothing helps and I'm out of ideas.

@chrisvp Where did you get the GS power supply? I have exactly the same problem, received a new GST power supply but the problem still persists.

Hi All, One of my older type UMOs with heated bed upgrade has shown some temperature issues. When it was printing, the room started to smell like very hot PLA, you know, that semi sweet caramel-ish odour. Well, things turned out to be the hotend overheating while printing. It started of printing normally, but after a few minutes, the filament got so hot that it ruined the print. So I tried this a few more times and the same thing happened. I shut down the printer and got to bed. The next day I wanted to test if the printer also went overheated when I only heat up the hotend, but to my surprise the hotend now shows 0ºC. So I expect the sensor to be broken, because I don't get any MINTEMP or MAXTEMP errors. Can somebody confirm this? Or do I have to look at the amplifier board? Also, my newer UMOs only use a PT100b sensor without that board, resulting in a cleaner wiring. Is there any way to convert the old amplifier & type K thermocouple setup to a PT100b? If yes, is there a step by step guide somewhere?

Hi guys, I noticed something lately. I have 3 old UMOs with the thermocouple board on the printhead, the other 4 UMO+s have the sensor (PT100?) attached directly to the main board. When I print the same gcode file on both types of printers, I get different results. The UMO prints Colorfabb PLA/PHA at 220ºC without stringing and with a smooth but matte top layer. The UMO+ prints with same settings, but there is significantly more stringing and blobs. Also the top layer is a lot more shiny. When I lower the temperature manually to around 200-205, the prints look a lot more like the older UMOs. I want to do a comparison between the readout of the sensors, but I have to find/make some kind of heater block where both sensor fit in together. Does someone have an explanation for the difference in print quality? Is the temperature readout wrong on one of the machines?

Yes I did.

Hi All, I've got two new UMO+ machines and assembled them last week. When I try to make a print, it looks like there is slack in the belts, because circles have flat sides on them. But after tightening the belts (which were already tight enough) I found out that the problem lies somewhere else. One of the X-axis rods (the one on the front) is forcing itself out of the machine when it is rotating. Because of this pushing force, one of the endcaps that keep the rods in place is grinding away. Apparently it also creates so much friction that the print quality is greatly influenced by this effect. I added a steel nail through the center of the endcap to try to lower the friction, but the nail has just completely eroded after a few prints. There is a severe problem here. Has someone also experienced this effect and/or has a possible solution?

Fellow makers, I produce parts that have to be pretty much identical each time. I make about 600-1000 of these parts each week. But I constantly run into a first layer extrusion problem. The problem occurs on all my UMO+ machines (5 of them) What happens is: the first layer is either to high causing under-extrusion and sticking issues, or to low causing over-extrusion and material smearing issues. It varies between each print run. So on the same machine, the first layer on the printrun 1 can be too high, but the first layer on printrun 2 can be to low. It happens with the identical gcode, as well as between different gcodes. I feel like the mechanical Z-endstop is affected by the temperature in some way. Or the printbed expands/contracts with different temperatures causing it to bend very slightly. The ambient temperature varies somewhere around 22-28 ºC, depending on the outdoor temperature. Each time I have to wait for the printer to lay down the first layer of all the 12 parts in 1 printrun, to see if I have to adjust the bed levelling screws. Sometimes having to stop the print and restart. Very tedious, time consuming and frustrating with multiple printers. Is there anybody who also run into this problem and has a possible fix for it?

Thanks for your input, but I checked this already. The bed actually is very flat and the first layer always prints great. But the underextrusion problem keeps happening in the entire print after that. A varying Z-height can be visible in the first few layers but dampens out and disappears when you print taller parts.

Hi fellow makers, I have a BCN3D Sigma for more than a month now and using Cura and S3D with it. But somehow I can't get a nice and smooth infill. The infill seems to have underextrusion at random places, but it also isn't random at the same time. Every time I try to print a simple calibration cilinder with 100% infill, there are little open spaces between the infill (see picture). The weirdest thing about it is that the underextrusion happens on the same place when I print the same gcode multiple times, BUT I also get the same gcode to be printed out fine sometimes. I have tried every setting that possibly has to do with it in cura, but also in S3D. Sadly the problem has not been solved yet. I want to print colorfabb pla/pha with at least: 0.15 layers, 215C, 60mm/s, 50% fan speed. So these are my base settings. I thought it has something to do with the hotend and cooling fan setup, maybe thermal interference between them (fan cooling the nozzle too much or whatever). When I crank up the temp to 250C, prints are printed better, but other temperature issues appeared. So maybe slowing down the layer time. At 20mm/s it looked better, but this is just terribly slow. Fan of also works (but not always), but I don't want to print without the fan because of sagging issues. Also I thought different layer heights may work, but for as well as 0.2 and 0.1 layers, the underextrusion happened in many cases. I also tried different materials and different brands on both hotends. But it happens in every combination. Altough it looks like the left hotend is worse than the right hotend, but I'm not 100% sure about that. So that's were I started looking at mechanical issues. Dirty drivegear maybe, or extruder skipping steps? No, sadly that was not the case. Maybe the wrong steps per E? Nope. When I installed a (slightly modificated) UMO geared extruder to see if that works, it initially looked like it worked. So I made two identical UMO geared extruders with a different mounting bracket and installed those (ofcourse calibrated the E-steps). After some testprints, the problem appeared to be still there. Still no grinding issues, skipping steps or wrong steps per E, so the amount of extruded material seems to be right. By the way, those extruders proved me to work very reliably, I have them on 6 UMO's. So I guess the extruder is ruled out at this point. Other things I tried which all didn't work: • Oiling the filament • Cleaning the nozzles • Thermal grease between the thread of the nozzle/heaterblock and heaterblock/heatbreak • Hotend autotune (10x) BCN3D is sending me new hotends to test, but I'm afraid this is not going to help since the construction of the hotend+carriage doesn't change. Does someone have any ideas to solve this problem? Also: I don't seem to be the only one having these issues, but many people don't even mention it since it's their first printer and have different expectations or no comparison. Edit: Below you see exactly the same gcode printed at one of my UMOs. Did a 205ºC temperature and 300% speed override, still printed fine.

Hmm that sucks. That is actually exactly what happens with the small fans, they start vibrating. But at certain 'random' PWM values they do spin though. It still doesn't explain why two out of six 25mm 12V fans from one same batch do work perfectly fine, tested on each printer. I pulled apart three fans. One not functioning 25mm, one properly functioning 40mm fan and one properly functioning UMO+ 50mm fan. The only potential difference I can find is the Hall sensors that have been used inside the fan's "circuit boards". The small not working fan has a 276 sensor, the 40mm has a 277 and the ultimaker has a 266 sensor. Maybe I should desolder the Hall sensor and replace it with one from a working fan. Because I'm not really into testing all kinds of fan brands with a price tag of >€15/fan.

@amedee Thanks for your reply. Today I received 24v GDT 25x25mm fans. But: these also cannot be controlled properly on the umo+ machines. They start jiggling for a second (and stall afterwards) at PWM 50~200 and rotate at full speed above that. While other 24V and 12V fans that I have, do run properly at a PWM >50. Tested on all my machines. The weird thing is that the two GDT 12V fans on the first upgraded machine (UMO A, as in first post) are functioning very well. They are switched in parallel. These are exactly the same GDT fans as the 'non functioning properly' ones, also from the same supplier. All the other GDT fans only rotate near full PWM. Also, when I search google for PWM controllable fans, they all have 4 pins. No one mentions that 2 pin fans can be controlled over PWM. Does anyone know a decently priced PWM controllable 25mm fan, that has two wires?

I thought the output was 12V, because the standard fan is 12V as well.. Is it a better idea to use 24V fans on those machines then? Or will the airflow drop significantly?

Hello, I have modified my UMOs with an E3D hotend setup with three fans. One 30x30mm fan for cooling the upper part of the hotend, and two 25x25mm fans for cooling the 3D prints, creating a crossflow. I'm running into a weird issue from the fans that I can't seem to solve by myself. I bought a total of 4 25x25mm 12V GDT labeled cooling fans from ebay a while ago. Two are installed on one UMO (lets call it UMO A), those work great. The fans can be PWM controlled all the way down to 30. But, two 25mm fans front the same batch, installed on the other UMO (UMO B), only work at around full PWM, about 220-255. When I try to let the fans rotate at lets say 140, the fans wiggle for a second and stall afterwards. Also when I manually give the fans a little start up push, nothing happens. What I already tried to exclude possible causes: • Stock 50mm fan works fine on PWM control on UMO B • Random 40mm fan also works fine on PWM control on UMO B • 25mm 'broken' fans from UMO B also don't work on UMO A • 25mm 'broken' fans from UMO B do rotate at full speed when PWM is 220-255 • 25mm working fans form UMO A also work on UMO B So this means it is not a printer issue but a fan issue. Well, since I bought them in one batch I don't understand what the cause can be. I've attached a picture of a torn apart 'broken' fan. Of course I'm not going to tear apart a working fan for comparison though. Hopefully someone can help me in this PWM mess.