Sunday, Oct 21 2018
EZABL from TH3D
Look what arrived in the mail, today. I didn’t know USPS First Class mail delivered on Sundays. Or perhaps the box had been in my mailbox since late yesterday afternoon. In any case I got an email from TH3D saying the kit had been delivered and it was in my mailbox when I checked.
Power supply access
Route power wire
Power connections
I took the bottom cover off of the control unit and unscrewed the power supply to make access a bit easier. The supplied wire fit through the grommet in the rear of the control unit along with most of the other wiring. Red to +V, black to -V.
Strain relief
After re-attaching the power supply I cable tied the power lead to a side vent slat on the control unit case. The goal is to provide some strain relief. I don’t want an accidental tug on the power wire to do any damage. I replaced the bottom cover of the control unit and turned my attention to wiring up the sensor.
Loading new software
The other end of the power lead goes to the sensor control unit. So does the sensor itself. I didn’t get any pictures of wiring up power and the sensor. The instructions for this kit called for cutting the connector off of the Z-limit switch wires. Instead I dismantled the pins from a spare 2-wire JST connector and attched then to the stock Z-limit switch connector. The wires from the pins were connected to the sensor control unit. You can see this in the picture. [Note: the pins were unprotected when the picture was taken. I was still testing the various connections.]
With everything hooked back up to the printer it was time to calibrate the sensor and set the Z-offset. TH3D has written instructions and a video on their website, there is no need for me to describe the procedure here. I started the process by re-loading my SNAFU version of Marlin with the needed changes for the sensor, specifically inverting the Z_MIN end stop signal polarity.
Testing Z-offset
Clean up cabling
After calibrating and setting the initial Z-offset I fine tuned the Z-offset amount with a couple of test prints. Everything seems to be working. That was the easy part. Next up was the time consuming job of cable management.
I used some M3 hardware with matching T-nuts to mount the sensor control unit to the side of the frame base. With the position fixed I played with sensor and printer wiring until I was happy that Z motion wouldn’t interfere with Y motion and that neither would interfere with static cabling. Finally I wrapped a few bundles of excess wire created by removing excess slack with friction tape.
I am keeping the bed leveling knobs. I’ll use them to get the bed close to trammed with with the print head when I change/clean the build plate. The Z-offset will have to be set again, too.