Diabase crash detector

thingiverse

This device enables mounting the heatbed of the Diabase H-series on springs and attaching switches underneath the printbed to detect when a nozzle crashes into the bed. This is necessary because the diabase H-series is so powerful that it can bend its extruders before motor stalls, even with software stall detection (M915) enabled. Note that this solution likely only works if not using the machine for milling and will result in losing the ability to easily remove the heatbed. To implement this solution, mount the heatbed on 19x13x1.2mm compression springs with seven turns, grounding flat ends. Place a Cherry DB1C-C1RB microswitch under each corner using a 3D printed mounting bracket. Pre-tension the springs by screwing bolts into the heatbed's pins. To keep the heatbed connector connected, mount the pcb with the heatbed connector on salvaged pen springs and M3x10 bolts. Ensure the heatbed cannot move in x and y directions and can expand when heated effectively by constraining it only in these directions using the front two pins. The front pins are fully constrained by a flat cone-shaped nut pressed into the mounting hole by the springs, while the back nuts are only constrained in z by having the springs press against the surface next to the mounting hole. The exact configuration of the front and back bolts is as follows: Front bolts: - M3x16mm bolt - Big wing nut - Flat cone-shaped nut (small wing nut with sawed-off wings) - M3 lock nut (DIN 985) Back bolts: - M3x16mm bolt - M3 nut (DIN 934) - Big wing nut - M3 lock nut (DIN 985) - M3 nut (DIN 934) To ensure power to the motors is shut down when a tool crashes into the bed, connect the normally connected terminals of the switches in series with the emergency stop. This resulted in the attached wiring diagram.