Ultimaker 3 - Rounded corners

[MAKE3DE 0]

We are having this issue with UM3.

This started when we updated printer to 5.2.11 firmware.

This has been confirmed by 5 users of UM3 uptill now if you have UM3 please make a test, and let me know.

 

Edges on corners are roundes as you can see on image bellow.

Also, I have done some measuring all sides are +0.2 and corners are extra +0.3 so this cube measured on sides is 0.5mm bigger than it should be.

I've added new printcore, done factory reset and tghten short belts still the same.

This is made with Cura 4.1 with ultimaker green pla and default settings. 

I have tried older version of cura 3.6 and same thing.

Edited June 19, 2019 by MAKE3DE

[whero 0]

I also have an issue with rounded corners that are more prominent now than I remember them to have been previously. Might be related to latest firmware, and when comparing old test cubes printed with pervious verions they don't show the same issues.

 

Anyhow, i found this thread and increasing wall acceleration and lower wall jerk seems to have helped a little for me.

 

[gr5 2,210]

When the printer slows down for the corners, the pressure in the nozzle is still high and so it overextrudes.  Basically anytime the head slows down it overextrudes and anytime it speeds up it underextrudes.  And it has to slow down for corners.

 

The fix is to disable accel and jerk control (so it spends less time on the corners and accelerates the hell out of there).

Also lower the print speed.  I find 35mm/sec is pretty good but 25mm/sec is even better.  You can experiment in the TUNE menu and play with the feedrate % and keep notes and get lots of data on just one cube.

 

However disabling accel and jerk control will increase ringing and that red cube above has an X with some shadows/ringing.

 

So you can compromise and leave the accel/jerk control at defaults and instead just slow down the print.

 

Also it's good to keep all infill and shell speeds at the same.  As I said before, every speed change is a problem.

[whero 0]

Excellent explanation @gr5. NOW I get it (I hope), even though I have read it on many places previously including comments from you. Thank you!

 

After inspecting previous calibration cubes I saw the rounded corners has been there all the time and as apparent. My test changes to acceleration and jerk did nothing upon closer inspection (might been to small changes). And it's mostly print using AA0.4 at .2mm layer height that have the issue. AA0.4 at 0.15mm looks a lot better, AA0.25 is more or less flawless and AA0.8 at 0.4mm have good corners. All prints using defaults for UM3 and UM PLA.

 

Slowing things down is not an issue for me, I'm almost never in a rush with my prints.

[geert_2 558]

At thicker layer heights, and at higher speeds, you have to extrude a lot more material in the same time, so internal nozzle pressure will be a lot higher. So there will be a lot more "overpressure" stored in the feeding traject that has to be released when the printer slows down. When printing slow and in thin layers, there is very little pressure build-up in the nozzle. I guess...

 

[MAKE3DE 0]

Thank You all for comments, I have tested this issue on UMS5 also same problem. As it is for now you cannot use Ultimaker 3 for anything higher than 0.1mm layer hight. Why did they set default speed at 75 if we can only use 25? This just makes no sense. Has anyone tried contacting Ultimaker directly about this, I have sent email on .info adress but I didn't get any response. 

[Smithy 1,145]

6 minutes ago, MAKE3DE said:

I have tested this issue on UMS5 also same problem

You will see such issues on nearly every printer.

 

6 minutes ago, MAKE3DE said:

As it is for now you cannot use Ultimaker 3 for anything higher than 0.1mm layer hight. Why did they set default speed at 75 if we can only use 25?

I have no problems printing with a higher layer height, but you have to adjust speeds and turn off jerks/acceleration. You have to find a good setup which fits YOUR needs, because turn off jerk will produce ringing after the corner.

 

And a higher default speed is not a fault, ok could be more optimized, but for non technical prints or prints where dimensional accuracy is not needed, it doesn't matter if the corner bulges out a little bit. 

 

10 minutes ago, MAKE3DE said:

I have sent email on .info adress but I didn't get any response. 

Your direct contact should be your reseller, because all support and customer service is handled by the resellers.

[MAKE3DE 0]

I tried many cheap printers, also I have large 3D printer that we designed but these don't have this issue. 

 

We bought Ultimakers because they are advertised for product development and on data sheet they state that dimensional accuracy is 12.5 microns but we did some measurements using microscopes and other optical measuring equipment and Ultimaker 2+ is even better than advertised but Ultimaker 3 at default settings has up to 0.5mm deviation.. 

 

I've tried support they responded first time, but haven't heard from them in month.

 

So what are my options here? I just want to know if Ultimaker is aware of this issue, and will this printer every be able to correctly at 0.2 and 0.15mm layer hight?