this is Martin from Hamburg, Germany. I just finished my very first printer build and so far managed to get a bunch of successful prints on my FT-5. Great machine!
However there is a sporadic glitch on some print jobs that really leaves me worried. Mid print, after maybe 30 minutes or so, the Z Axis steppers go full throttle upwards and drive the bed towards the print head, burying the hot end in the printed object. In one case they even drove the nozzle through the object and into the bed and pushed the Z axis stop - which works flawlessly during leveling and homing btw - upwards during that move.
To make myself clear - it's not like the Z axis is stuck and the head is slowly working itself in. The bed actively quickly moves upwards. Everything jams, total mayhem, an unattended printer would probably suffer some damage. I added some photos.
In one case, I just closed and restarted Cura, imported the same object again, wrote the GCODE to SD, switched the printer off and on again - and the print just worked fine.
1. The STL files were all Downloads from thingiverse and converted using Cura 15.04.06
2. The GCODE files were transferred to a micro SD (Nokia, 512MB) that sits in a Sandisk SD Card Adapter. The SD Card was quick-formatted to FAT before printing use and is empty except 1 or 2 GCODE files
3. On the printer, I use the ft5_marlin_v3 Firmware that I compiled and uploaded using the Arduino IDE 1.6.7. LCD says "Marlin 1.1.0-RC6" on Startup
4. During prints, no USB connection to the printer exists
All files available on request.
Has anyone ever experienced something like that? All help appreciated!
Thanks and Best Regards