7) Auto Levelling Probe

Refer to this guide here on modifying the plastic for the auto probe to make it retract easier.

The Auto Levelling Probe subassembly fucntion similarly to a retractable ball point pen.

Parts are located in a bag labelled ZT-KIT-00127, located inside the "Kossel Common Core Component Kit".

Although the probe was first introduced on the Kossel Pro, it should work well for Cartesian printers as well for probing bed height and setting the first layer.

Prior to the start of a print, the probe deploys and triggers a Z-Min end stop. In the deployed position, the probe is lower than the print nozzle, thus allowing the end effector to sense the position of the print bed.

Touches to the probe are registered through the Z-Min end stop

When the probing is finished, pressing down on the probe locks it into the retracted state.

The parts for the Auto Levelling Probe are shown on the right.

Start by threading the main spring onto the probe strike pin, as shown on the right.

Thread a M2 Plastic Washer onto each of the M2 x 10mm SHCS, as shown on the right.

Locate 2x M2 nuts. Flip Auto Probe Body over to expose the 2 hexagonal indentation for the nuts, and insert them, as shown on the right.

Holding the Auto Probe Body in orientation shown, install the switch with text side facing out, using the M2 x 10mm SHCS + washer hardware stack built on the previous slide.

Lightly tighten the screws to finger tight, but do not tighten. For optimal performance, the switch needs to be centered correctly.

Bias the switch so that the actuation tab is roughly centered on the opening for the auto levelling probe.

Tighten the M2 x 10mm SHCS to lock the switch in place.

Slide Strike Pin and Spring combination from earlier in the build process onto the Auto Probe Body.

While compressing the Strike Pin, place the standoff on the flat side of the Strike Pin. Note: newer versions of this kit ships with 2 standoffs. Use the shorter one for the Mini Kossel, the longer standoff for the Kossel Pro.

Insert M2 x 10mm FSC from the countersunk side of the Strike Pin, tightening screw all the way with the supplied 1.3mm hex key. NOTE: newer kits will ship with blue thread locker pre-applied to this screw.

NOTE: It is important to lock the stand off in with no movement, by cranking down on the M2 x 10mm as tight as you can. Failure to do so will result in the probe falsely reporting a triggered touch.

The torsion spring is used to lock the probe into the retracted position when the probe presses down on one of the lock tabs for the HBP / Glass after the end of a G29 routine.

Install torsion spring as shown.

Secure torsion spring with M3 screw, fender washer and nyloc nut.