lordmao

OK, new finding, Flex PLA is such a pain to print some times... I have to print something which is basically a rectangle, roughly 15x4cm and only 0.5 in height. First attempt: 230°, 10mm/s, bed at 60° => FAIL I was not close to the printer during the print and when I came back, I discovered the part in one side of the printer, completely torn, and the nozzle was hidden behind a huge ball (2cm to the diameter) of melted Flex PLA which was hard as rock. I had to heat up the head to remove what I could from the nozzle, clean the mess by unscrewing the fans, etc. So I decided to launch the same print, but this time I would stay around. The reason it failed was retraction of the Flex PLA. As it's quite long and it was printed with the long sides of the rectangles facing the right and left sides of the UM², the small side of the rectangle which was in front has decides to lift off to the point when the print head would crash into it and therefore unstick the whole part from the bed (I stopped the print before obviously). To counter that, I have changed the position of the print on the bed, with long side of the rectangle parallel to the back of the UM, I have added a brim of 30 lines, increased the bed temperature to 115°, increased the head temperature to 250° and limited fan speed to 50%. I also increased the speed to 30mm/s. => Printed perfectly ! (but hard to remove from the bed) So I ran a second print with the same configuration, failed in the middle due to filament being eaten by the extruder. I think this is due to the geometry of the part being printed, which contains a lot of small dots triggering retraction and so grinding of the filament due to its softness. And it was a huge mess to remove the print from the bed as the part was not complete and therefore not fully resistant to mechanical solicitation. Overall, printing at higher temp on a hotter bed will help but removing the print from the bed will then be a real pain, as stated by garycmartin.

I'm printing a cover for the antenna of a walkie talkie using Flex PLA from Ultimaker (white version, it may have some influence). I have used the same parameter as Peter in the video gr5 has shared: - 230°C - 10mm/s I use heated bed at 60°C and fan at 100%. So far, it's long to print but it's worth it as it looks absolutely perfect.

There is still one hour to go, but I think that I can safely announce that it will do. Only a bit of lifting off. I am printing at 250°C, on a 115°C bed, fan speed 10% (fans off seems to decrease the quality too much), 0.1mm layers and 20mm/s. That way I'm also avoiding stringing and I keep quality high. But I had to start the print with the bed temperature set to 80°C and only after the beginning, rise the temperature to 115°C. Otherwise the ABS is melting in the nozzle for too long before being extruded - it takes the bed something like 15min to reach 110°C - and it is stuck in there. The feeder is then digging/cutting the filament. So I had to change material, cut the "bitten" portion and reload. The first material to come out of the nozzle was then yellow/brown (who said overcooked?)... So starting the print with the bed still warming up seems to do the trick.

I do agree with you, even if I already have burnt myself a few times for being too hurry :mrgreen: So now I prefer waiting a bit more. But it's not that long to cool, only a minute or so. The realy long phase is the heating of the bed.

Yes I am using a sheet of paper to fine-tune the leveling :wink: But I will not try tweaking the gcode for the moment. I will wait to see if I can solve this "normally", as it's the first time I'm having this issue.

Okay... Now I probably have tried to be too accurate while leveling the building plate. The first layer just won't print, the nozzle is so close to the building plate that what I have can't really be called a layer. It's thiner than anything I thought was possible, and the feeder was crying a bit. So I just have to wait for the build plate to cool (soooooo long to heat up and sooooo long to cool afterward) and restart the leveling process again.

Yes the brim was still flat on the bed, and yes there was some space between the lines of the brim. I won't go for under-extrusion as every other portion of the print was just fine and the speed very slow. But I will check the bed level to see if it might come from there as well. Readjusting bed level, heating bed at 110°C and turning completely off the fans, these should help me print that out. Thanks

Thanks for the tip, I will try that and I will let you know if it worked.

I have to add that the first 5 to 10 layers are perfectly fine, but it start lifting after that. And from then, the effect only increases, until touching the carter around the fan.

Hi everyone, I am trying to print a part in ABS, but the shrinking is driving me crazy. Neither heated bed nor glue will prevent it. But I have noticed that it always happens in the same corner of the building plate, the back left corner (the closest to the extruder origin position). I have tried to turn the part around and it always start from the same corner. I have to abort the print before the fan carter hit the shrinking ABS... The heated bed is set to 80°C and I'm printing at 250°C 20mm/s 0.1mm layers. I have tried other settings, without improving results. Is there a way to avoid, or at least limit the shrink? Without a heated chamber that I don't have? Do you have any idea what could be the cause behind the shrinking always starting from the same corner of the building plate, no matter the orientation of the part? Thanks for your advices.

Yes, there are a lot of "hilltops". And as the outside circle is nearly as high as the highest part of the building, I had to remove quite a lot of "travel crap". But I found these to be fairly simple to identify/remove after a bit of practice. They pop-up easily when I use a knive as a lever.

I had to do a bit of cleaning after the print between most of the raised details, but the small parts to remove were hardly connected to the real design, so they were easy to remove (I use a sharp knive as a lever). The main issue with this accuracy of details is to check if what you're about to remove isn't actually part of the print. But the light from behind also helps a lot to smooth the details. You don't see much the watercolor effect for instance. Otherwise, I simply used the "high" auto setting in Cura, but I'm sure that the "normal" would have done a very similar job as well. Fine-tuning the parameters could probably improve the initial quality of the print.

On an other subject, but still playing with light, I have tried to print a small medal. It came out a bit like watercolor painting, and I really like the result with the light behind. The original model is really thin and is 12cm wide. I have scaled it down to 5cm to the diameter in Cura so the actual thickness of the building has also been decreased from the original design (around 0.8mm thickness for the front tower, nearly 0mm for the back). Even the cloud on tho is clearly visible. This printer is amazing!

Hi everyone, I have just received my brand new UM2 and I wanted to share the traditional robot here :smile: I have to say that for the very first out-of-the-box print, it's quite fantastic! I'm totally in love with this machine. It's more user-friendly than my toaster :-P I can't wait to know the printer a bit more and make some really nice prints, like the rose from NachoKaoS :wink: Cheers Mao