Induction Probe Auto-Level Mount for Printrbot Simple 2013
by KT421, published
Induction Probe Mount for Printrbot Simple 2013. Remix of another probe mount, but modified for use with a larger probe, on account of the larger probe came with free two-day shipping.
The setup is exactly the same as for the autolevel probe that Printrbot sells directly, but be careful that the probe doesn't bash itself into the screw at the home corner of the bed.
This COMPLETELY and TOTALLY fixes unlevel print bed problems, including the dreaded Simple Y-axis Sag. That's right, the arm sag is accounted for along with the bed unlevelness. It's a perfect smooth first layer.
This thing was made with Tinkercad. Edit it online https://tinkercad.com/things/lcJDIHDY9H7
.4mm layer height, 30% infill. Attached using the same screws that were already in there holding the hot end in place. I should probably use longer screws, but the hot end seems to be secure.
These instructions are for installing an aftermarket induction probe to a Printrbot Simple 2013 with fan upgrade. The probe this mount is designed for is from Amazon: http://www.amazon.com/gp/product/B008MU1GEY/
The probe comes with bare wires, so you'll need to wire it up to a connector yourself. The wiring order is black-brown-blue, with the clip facing down. You'll need http://www.digikey.com/product-detail/en/0022013037/WM2001-ND/26433 and http://www.digikey.com/product-detail/en/0008500114/WM1114-ND/26475 to put together the connector. Ideally you'll be able to use a specialized crimp to get those into place, but I used needlenose pliers. A dab of solder can also help, if needed.
Once you have it wired, it replaces the Z-stop on the printrboard. When testing the probe, a light on the top means "No metal here" and no light means "I found metal!" You will need a metal bed for this to work such as the aluminum beds Printrbot sells.
Install the mount next to the hot end. Discard the two washers from the probe. Take one hex nut off the probe and slide the probe through the hole in the mount, and put the nut back on on the bottom of the mount. Adjust until the probe is a few mm above the nozzle, with enough clearance to not scrape the screws along the edge of the bed when the nozzle is at first-layer height. When it's in a good spot, tighten the hex nuts to keep it in place. You only need to get "close enough," about 5mm away from the bed, finer calibration is done later in the firmware settings.
Save all your firmware settings, because the new firmware will wipe out all of your hard-won motor steps and other settings. Use the M501 command to get it to spit out its settings and copy/paste those into Notepad.
Install the new firmware. It's found here, in the product description: https://printrbot.com/shop/auto-leveling-probe-2/
Once your new firmware is in place, go back and set all your M92 and other calibrations back to the right values using the settings saved in Notepad.
You now need to tell it to use the new probe and firmware at the beginning of each slice, so open up slic3r settings, go to Printer Settings, and look for "Start G-Code." In that box, replace:
G28; home all
G28 X0 Y0; home X&Y
G29; home Z
G28 is ye olde homing command, meaning "Go this way until you hit an endstop, and then you're at home." You are telling it to only do that for X and Y now, and you're using the new command G29 to home Z, and that new command is where the fancy auto-leveling is happening.
Back in the printer controls, we need adjust the offset of the probe to the hotend by using the new M212 command. We're telling the printer how far the nozzle is away from the probe. Send this to your printer:
That starts you off with a positive offset in the z direction, so it will probably be too high. However, too high just means trying again. Too low means ramming into and maybe damaging your print bed. Leave X and Y offset at zero, even if there is actually an offset. The firmware can't actually cope with that right now (unless there has been an update since I wrote this) so it's best letting the printer think that the probe and the nozzle are co-located.
Set up a large print with a skirt, and give it a try. It should probe the bed in three places, then warm up and start the print. Watch how high it is, then kill the print job. Use the M212 command to adjust the Z offset down by small increments until you get a good first layer. You may need to go into negative values; Z-0.8 is what ended up working best for me.
Video of the calibration process, courtesy of the Printrbot dude: https://www.youtube.com/watch?v=lgVmNuwMH68