Hi, I'm getting into 3d printing and have had some successful prints so far.
I have a Richrap 3DR printer with a probe built into the effector. The hot end is mounted on a spring loaded hinge and there is a switch that detects when the nozzle touches the bed.
I found that whenever the print gets too high I have a problem with the nozzle colliding with the print causing failed print. This led me to attempt to fine tune the bed leveling using M666 commands.
I found that my bed was quite level, however there is a spot between the x and y towers that is printing very close to the bed (0.05mm instead of 0.25mm). I'm assuming that a tower position must be out and G30 should be able to pick it up and correct.
The G30 command sends the nozzle crashing into the bed, the motors skip some steps and it is ruined.
Here's a youtube video of the problem. The paper is there to prevent the nozzle from scratching the glass. Any help you can provide is welcome.
G30 crashing into bed
