Z-Probe X Carriage for NopHead Mendel90 (dibond) with an E3D

thingiverse

This is a modified version of the Dibond X Carriage that enables a standard inductive sensor to be fitted to the Mendel90, allowing for metal beds' Z height probing. Currently, this design only works with longer hot ends like the E3D. If you try to use it with the original shorter J-head, you will need to modify the Wade's block to move the NEMA motor higher up so the Z-Probe can fit underneath it or get a shorter probe than the common one most people are using. If you don't want to go through that trouble, my original design (http://www.thingiverse.com/thing:599262) can be used with a J-head. The reason for creating this was I discovered my original design suffered from inaccuracies when using springy filaments as they would tug on the extruder assembly during probing causing the X carriage to twist very slightly in the Y direction. Because the probe in this design is Y-offset from the extruder, this twisting would cause the probe to get closer to or further away from the bed creating erroneous results. If you are planning to print very thin layer heights like 0.1mm, this error could be the difference between success and failure. In this new design, there is no Y offset; only an X offset of 52mm, meaning the probe is less affected by the twisting. Also, due to the fact that the probe is rigidly mounted to the X carriage, its repeatability is also improved. IMPORTANT: Although this design is more accurate than my previous one, it is also much harder to experiment with and adjust because of the Z-Probe wire exit being very close to the NEMA extruder stepper motor. I strongly recommend that you get your Z-Probe working with my simpler design (http://www.thingiverse.com/thing:599262) before attempting this modification. Instructions Printing out the X Carriage The X Carriage is designed to be printed without supports using solid infill. It should be the correct size when printing with ABS. It's not recommended to use PLA as the carriage is too close to the hot end and may melt. Fitting the sensor Place one of the nuts from your sensor inside the carriage by inserting it in from the top, pushing it down, and rotating it until it's horizontal (with the help of a screwdriver or other tool - see photos). You can then screw the sensor inside the nut in the carriage (being careful not to cross-thread it) until it reaches a depth where the tip of the sensor is the same height as the tip of your extruder will be once it's fitted to the carriage. Once you have the correct height, fit the spring washer and remaining nut on the bottom and loosely tighten. Modifying the Wade's block Using a saw, cut a small section out of the motor bracket part of the Wade's block underneath the NEMA stepper motor (see photos). This is so that when the block is fitted on the carriage, the bracket doesn't overlap the hole where the sensor is fitted. Reassembly Reassemble the X Carriage as per NopHead's original instructions. You may need to use a knife or other tool to open up some of the holes and slots in your new print. Please note that the NEMA motor will press on the wires exiting the top of the sensor, which is unfortunate but unavoidable without designing a new Wade's block with different motor mounts. Please be careful not to damage the wires by stressing them too much. Final adjustment After reassembly, adjust the sensor height by twisting it so that it triggers at the exact same time as the nozzle touches the bed. I found I had to loosen the wing nuts holding down the Wade's block before I could rotate the sensor, then once adjusted, I would have to tighten them down again to test the height. This is one of the reasons I strongly recommend starting with my simpler original design first (http://www.thingiverse.com/thing:599262). When you do the firmware modifications, set the Z probe offset to zero (you don't have to do it this way, but that's the way that worked best for me). Tip: If you can't get your probe high enough because it hits the motor, lower your E3D by putting a metal washer between it and the Wade's block. Further information For further information, please check out Thomas Sanladerer's excellent video here (https://www.youtube.com/watch?v=EcGFLwj0pnA). Also, the comments on my original Z-Probe bracket are worth flicking through.