* Disclaimer: This mod has you working with a high wattage power supply. If you damage yourself or your printer I am not responsible! *
Nov 29 2016
Description: This mod will enable auto-bed leveling / tramming on your printer. The leveling only does single-plane best-fit offsets. It might not be able to compensate for warped beds and rods or a very unsquared printer.
Before you start:
*There are some issues with Thomas’ directions but it does mostly a good job explaining what you’ll be doing.
· LJ12A3-4-Z/BX Inductive Proximity Sensor Switch NPN DC6-36V
· Inductive printing surface
- - - Black Wanhao buildtak mat on metal bed
- - - 3mm (or thinner) glass directly on metal bed
- - - 3mm (or thinner) glass with aluminum foil squares glued on underside at sensing points. Start with a full foil underside surface until you know where the sensing points are. Then cut down the foil into smaller squares and glue.
· Two 1/4W resistors (Pick one of the these pairs. They’ll all work.)
- - - 390K and 100K
- - - 39K and 10K
- - - 3.9K and 1k
· (2 pieces) 6in of insulated braided wire
· Heat shrink tubing 4/5 AWG
· Solder, soldering iron, ect
· Misc. wire cutting tools
· Electrical tape
· 40PCS Dupont 10 CM Male to Female Jumper Wire Ribbon Cable
· 3D printed mount for sensor https://www.thingiverse.com/thing:1924458
1. Print and attach a sensor mount for your printer.
2. Solder together a voltage divider and connector plugs to the sensor. Don’t take shortcuts! You’re dealing with high voltage. Heat shrink then tape everything up. See diagram and photos.
- a. 5V out is a female dupont
- b. Gnd from voltage divider is female dupont
- c. Blue Gnd wire is male dupont
- d. Brown 24V Input wire is male dupont
3. Solder together your braided wire and connectors for power
- a. V+ 24V from power supply is female dupont
- b. V- Gnd from power supply is female dupont
4. Turn off your printer.
** Update the firmware on your printer before connecting the sensor wires.**
5. Flip over your printer and screw down braided ends of power wires to V+ 24V and V- Gnd. Draw out the other ends through the printer’s side opening.
6. Mount your sensor’s blue end so it’s about 1mm above the tip of the hotend. Tighten the screws firmly. Train the wire up through the clip in the top of the base and down the side of your printer. Give enough cable slack so it’s not pulling on the sensor at any hotend position.
7. Remove the z-stop button and mount from your printer.