Uncommanded Print Speed Help

[Juice_11 0]

New-ish to printing. I have had several large and small prints complete without issue and look great for a beginner. I have an Ender 3 V2, no mods, standard software default, using Cura 14.3. I have had several files on the printer where the test strip prints perfectly on the left side of the bed and as the head transitions to print, it speeds up to 500-700% speed. Needless to say it looks terrible so I stop the print. I am able to "Tune" on the menu to 100% and that will fix the issue but when I go back to the main menu the "Tune" goes away and the file speeds up again. I am using PLA on a .4mm nozzle with the following settings: print speed-50mm/s, travel speed 150mm/s, infill 50mm/s and wall speed at 25mm/s. I have also had some files ( I get most from Thingiverse) run the test strip on the right side of the bed at a ridiculous speed and glob up and never proceed to the middle of the bed to print, I also stop those from printing and have chalked those up to bad files (or n00b user error?).

 

I am lost. I don't like leaving the menu on tune where I can't see the status. When I tune down to 100% on the printer everything seems fine. Is there a setting I am missing while slicing the files? Is there a setting/method to set print speed for different sections of a print? 

 

I am looking for beginner tips of what to try or see if anyone else has had this issue. I am lost and am not sure what to do, any inputs/guidance would be greatly appreciated. 

 

Photos:

1 - Example of a speed up, 711% lower left corner

2- When I tune it to 100%, everything is great but I have to stay on this menu

3 - Great level tune/test, but need to stay on the tune menu and decrease speed before the item begins printing after the test strip. 

[GregValiant 1,251]

In Cura go to "Settings | Printer" and down at the bottom will be "Manage Printers".  With your printer active go to Machine Settings.

On the bottom left is the StartUp G-Code.  That code sets the basic printer settings including the purge lines you see on the left side when a print starts.  Look and see if there is an M220 in there.  If there is it should be M220 S100 (for 100% feed rate).  Only M220 will have an effect on the print speed you see in the tune menu and on the LCD.

You can post a "bad" gcode file here.  The best troubleshooting file is a 3mf project file.  In the File menu there is "Save Project" that will save the entire Cura setup and include your printer, the model, and all your Cura settings.

[Juice_11 0]

Thank you for the starting guidance. I should note that I am on a Mac as well. I was able to find the Machine Settings, there is no M220 in the lower left for Start G-Code. Is this something that I can edit and have saved to apply to every print as a default? If so, is that the next step. Thanks again, this has been frustrating me for most of the afternoon. 

CE3_Cuddlez Paint holder test.3mf

[Juice_11 0]

This was a test of a paint stand for my wife, a painter. Designed by a friend. 

[GregValiant 1,251]

When I slice the file the only speed settings in the gcode are 120mm/sec for travel and 50mm/sec for printing so I don't see any problem there.  That also means there is no problem with the StartUp Gcode.

One thing you can try (and that you should do) is to put the following lines at the end of your StartUp Gcode:

M220 S100 ;reset feed rate

M221 S100 ;reset flow rate

Those are handy in case you tune a print while it's running and forget to reset the feed and flow when the print is done.  With those in the StartUp Gcode a print will always start with the feed and flow at 100%.

[Juice_11 0]

I just tried it with the added M220/1 you provided. Similar problem. Homes to the start point fine, but I had to go in right away because the speed percentage was 892% as seen in the picture. I saved the file I attempted to see if you might have any insight. Again, It was fine when I adjusted to 100% manually, did two rings of the test strip around the item and I went back to the main menu as a test, sure enough, right back to 892%. 

CE3_Cuddlez Paint holder test.3mf

[Juice_11 0]

I just tried a print that was successful the week we got the printer and it immediately jumped to 447% before the test strip and the print bed started tweaking out, so I shut down the print. I'm lost. I attached that project as well. I bet if I manually overrode it to 100% it would have been fine, but I shouldn't have to do that each print. 

CE3_OcotoArm-v3-Old-Tighter.3mf

[Juice_11 0]

You aren't going to believe this. Apparently there is a bug with this firmware that when the file name is larger than 22 characters, it exhibits some of the behavior I am seeing. I renamed the Cuddlez file from before and it is staying at 100% for the build so far. 6 hours I have been messing with this. 6. HOURS.

[GregValiant 1,251]

Well it's good that you figured it out.  But I still don't get it.  I could understand if it refused to print the file, but starting the print and jumping the feed rate to 900%?  That's just dumb.

BTW the limit was 16 characters on the 8 bit boards like I have.