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I started a print about two hours ago using octopi and gcode exported from mattercontrol, and at some point (I was not in the room at the time) the head just started slamming into one of the towers. The print was well within radius and had been printing flawlessly to this point. For the record both mattercontrol and octopi list the printer radius as a conservative 260.

This is not the first time this has happened, though I thought it may be due to improper homing or poor calibration. I rewrote the beginning script to verify homing was done and recalibrated.

Does anyone have any ideas?

Did you happen to record a timelapse in Octoprint? That might tell the tale.

I suspect skipped steps, mechanical interference, or a slipping belt pulley, but it's hard to guess without knowing more details.

I did not, I've only been using octoprint (and indeed my Rostock) for a short time. I will be sure to do so. I'll have something the next time this happens.

260 is not a conservative radius. 280mm is the approximate printable diameter for an RMv2. Radius is half of diameter.

...Oh, and if you meant diameter, there was also a thread about the latest version of MatterControl not properly importing the bed shape settings from the latest Slic3r, resulting in prints not being properly centered. If you're using the latest MC, you may need to either generate your gcode in standalone Slic3r or use another slicing engine.

Sorry, meant diameter.

Well, I haven't gotten a chance to print yesterday (overtime, a blessing and a curse). Visually, the print did look centered and within bounds. It got a fair way up the print (several sharkz clips) before having a problem, and the raft should have exceeded the radial distance from center of any part of the print.

Realized I can't do a timelapse because I have a pi B model, and I can't seem to find a working hub for it. One port for the printer, one for the wifi stick...