Why do bad things happen after the print finishes?

Printer = Taz 3
Printing from = SD
Firmware = stock
Slicer = Slic3r with Lulzbot recommended .ini settings

Occasionally post print my printer will do silly things after seemingly printing successfully such as stopping immediately and saying “Wait for user input” while the hot end melts the print (no turning off of heat, homing or kicking out of the bed). Worse (and fortunately less common) is the dreaded Z axis drop. I just printed a calibration code and upon completing the hot end just torpedoed straight into the print which broke the print, got melting ABS all over the hot end, made one Z threaded rod change position significantly and of course hosed the bed leveling.

Note I do have a computer connected via USB with Pronterface running (but not monitoring) that I use for manually moving the hot end around and more commonly manually extruding to allow picking out the grooves in the hobbed bolt.

Any ideas? The end of the aforementioned code is below…

G1 X161.547 Y125.846 E19.61336
M204 S1100
G1 X162.453 Y126.311 F12000.000
M204 S3000
G1 X160.689 Y124.547 F3070.866 E19.64539
G1 X161.130 Y124.547 E19.65106
G1 X162.453 Y125.870 E19.67508
G1 X162.453 Y125.429 E19.68075
G1 X161.571 Y124.547 E19.69677
G1 X162.012 Y124.547 E19.70243
G1 X162.453 Y124.988 E19.71044
G1 X162.453 Y124.547 E19.71611
M204 S1100
G1 F1500.000 E17.71611
G92 E0
M104 S0 ; turn off extruder temperature
M140 S0 ; turn off bed
M107 ; turn off Extruder Fans
G28 X0 Y0  ; kick out bed
M84     ; disable motors
; filament used = 715.5mm (4.7cm3)

Since it only happens occationally, it’s probably not gcode related. You may want to run a series of prints by solely using the Graphical LCD controller to see if that occurs again.

I always use the LCD controller to actually print. I only use pronterface for pre-print hot-end manipulation (movement and extrude)

If it happens again, can you get and post a screenshot of the message when printing with pronterface? Are you starting a print with the GLCD controller but still have it connected through Pronterface? In general you don’t want to have it connected if you’re printing through the GLCD controller as can cause issues.

I have over 50 print jobs since this last happened so…not sure what changed but it seems to be happy now :smiley: