Getting more quality on my prints UM2 / PLA

[miho-tt 0]

Hello guys,

i got my UM2 last week and started printing my first parts. I need the printer for making master forms for later castings.

My first print was a small part, i did different tries at different speeds and temperature (200-240°C), but i couldn't find a perfect setting.

have you some feedback for me, what settings could be work well.

thank you

kind regards

 

[gr5 2,167]

2nd and 3rd from the right in your first picture look good - use those settings.

You have some stringing on some of those parts in the top picture. That can be improved by lowering the temp, lowering the speed, and increasing retraction distance. E.g. 70mm/sec, 220C, 5.5mm are probably good to start with.

In picture #2, the 4 parts in the background, the bottom layer looks like crap. It was printed much too high off the build plate. Re-level with paper. You don't need to touch the 3 screws, just do digital leveling with the dial and paper at the rear screw only. Paper should be grabbed a little bit by the print head. If you turn off power after leveling you will lose it due to a bug recently found. After power cycling it levels too high. You can fix *that* by turning all 3 screws such that the bed moves up by .2mm. And don't relevel. Until Daid comes out with a fix.

But your levelling was off by much more than .2mm I think. Make sure the bottom layer is .3mm thick so that the leveling doesn't have to be "perfect" and you can have an error of .05mm and still get beautiful bottom layer.

The two parts closest to the camera in the 3rd, final picture look pretty good but if you want better you appear to be getting some tangling on your filament spool. Move the spool to the floor to get further improvements and if you want it even better slow down the printing to 35mm/sec.

 

[gr5 2,167]

Do you have retraction turned on by the way? Without retraction one should expect stringing like the 3rd part in top picture.

 

[stevegt 1]

Hi Miho,

Yes, what gr5 said about the leveling -- if you just got your printer, you will likely see some issues with keeping the bed leveled, and these will cause all sorts of symptoms that look like adhesion problems and under and over extrusion, particularly in the first layers. I just got my UM2 about 5 weeks ago, and have been helping to work through the two bugs that are causing this.

The sum total of errors these two bugs could cause mean that you could see the nozzle mashed against the glass, or you could be a few mm too low, or anything in between.

The worst of these bugs seems to show up more on newer printers like yours and mine. Paradoxically, this seems to be because they have improved mechanically, reducing z-axis friction, allowing the bed to fall when powered off. Old-timers here in the forums have stickier z-axis mechanisms and will often not see what the problem is. :wink:

If you'd like to know more details, and/or help test the fixed firmware, see http://umforum.ultimaker.com/index.php?/topic/5935-z-axis-homing-inconsistent-on-um2-workaround-and-patch/?p=57095 for the latest unofficial version.

Until you get the firmware upgrade, I'd advise you to print something flat and simple to check the bed level, preferably only one layer thick, immediately before each print and without powering off or re-leveling in between. I was using leveling rings for this, but haven't needed to do this since upgrading to the fixed firmware.

Steve