Voron Trident Z limit brackets / anti headcrash

It is a very simple but potentially vital addon for a Voron Trident.

What it does:

• Mechanically limits the movement of the three Z-axes in minus direction as a critical safety measure.

• Because of bed mesh compensation I'd suggest a clearance of -0.4mm with respect to Z=0 (see below). In case of an error this low negative distance can be safely absorbed by the flexibility of the print head if an impact occurs.

Background:

• I've built my first Voron Trident and immediately went for sensorless homing for X and Y due to the umbilical setup. Now sometimes the X-homing occurs too early (despite careful threshold calibration). This leads to the print head not hovering over the Z-limit switch while Z-homing. This will lead to the the destruction of the print head if not aborted.

• Also with regular X-/Y-limit switches such a misalignment of the nozzle and z-limit switch is not impossible leading to destruction. (Loose cable in front of a limit switch.)

Parts required (BOM):

• 3x M5 10mm BHCS

• 3x M5 roll in T-nut

Printing:

• Please align the parts appropriately on the plate. Print orientation is wrong.

• Use recommended Voron print settings: https://docs.vorondesign.com/sourcing.html#print-settings

Installation and adjustment:

• Loosely mount the brackets on the 3 extrusions seen in the photos.

• Home all axes.

• Move Z position to 0. (G1 Z0 F5000)

• Alignment:

  • Use 4 pieces of paper and place it between the brackets and MGN-carriages. One sheet of paper corresponds to around 0.1mm. My bed mesh deviations are below 0.15mm, so 0.4mm gives a tolerance of 0.25mm.

  • Slightly push the bracket downwards and fasten the bolts tightly.