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As you start printing, you will find that bed leveling is one of the most critical things to get right.
Too high, and you end up with adhesion problems, spaghetti and failed prints. Too low and you crash into the bed. Uneven, and well, you get uneven prints.
Well, Thanks to hep from darren, we've both got our auto bed leveling sensors working and I have to say I'm loving it.
We are using a capacitive sensor since it's supposed to work with glass beds better. I print directly on glass and really haven't had any kind of issues with adhesion.
Sensor : LJC18A3-H-Z/BX Make sure is is the NPN NO (normal Open type).
If you are not using glass, or pei, you can look into using an inductive sensor. The trade off is that you might need to adjust the offset for a capacitive sensor as it is supposed to vary a little bit due to heat and humidity.
Firmware : Skynet 2.3 https://www.facebook.com/search/top/?q=skynet3d firmware development
Bracket : http://www.thingiverse.com/thing:1907394
Wiring diagram:
We've found that we are getting better results by powering the sensor with 12 volts instead of 5. The problem with that is that you don't want to feed that 12v of power into the z stop connector on the control board, as that is running at 5v. You don't want to let the magic smoke out.
Darren can probably explain this better, but basically wev'e wired a couple of diodes inline to prevent the 12 volt current from going across the into the signal pin on the control board. When the sensor senses the bed, it closes the connection, and from what Darren tells me this lets the signal get pulled to ground.
All I really know right now is that this works. The guy in charge of skynet claims you can run it off of 5 volts, in which case you could just hook up all 3 wires to the z stop pins on the board. The are also other wiring diagrams that use resistors to create a voltage divider circuit. So far, I've been using this and the magic smoke is still in the board.
Steps:
1) Print a bracket of your choosing.
2) Install the sensor
3) Grab the skynet firmware and flash your control board. It's pretty straighforward and the instructions for doing it are included in the download.
4) Fool around with the sensor to get it to sense your bed. You can use a combination of adjusting the height of the sensor in relation to the nozzle and turning the set screw on the sensor to adjust it's sensitivity.
5) Use the z control buttons on your favorite printer control software to adjust the nozzle down to where it squishes a piece of paper just right. Just like you did when you used to level your bed manally.
6) Record that offset (should be a negative number. Mine is -1.45 right now) and enter that into the printer as the z-offset.
Thats pretty much it. You can level the bed on the printer using the lcd screen and the buttons to select it, but what I've done is to just add the bed leveling as part of my start script. It gets prepended to any gcode that I send to the printer.
Here's what I have my starting script set to in Simplify 3d. Just like you probably already use the G28 to home everything, G29 will run the auto bed level. Skynet is defaulting to a 9 point level, which might be overkill. I know darren changed the config for his firmware to do a 4 point level. I just like to watch the sensor fly around the bed before it prints.
You can see some other extra commands I have in there that basically prime the nozzle by running a couple of lines along the y axis to get things ready to roll.
Here's a print I did using the wood fiber filament of a buddah body with a baby groot head. The filament feels a little bit like balsa wood, probably because I printed this with only 10% infill, so it is really light. But it seemed to print pretty well actually.
Too high, and you end up with adhesion problems, spaghetti and failed prints. Too low and you crash into the bed. Uneven, and well, you get uneven prints.
Well, Thanks to hep from darren, we've both got our auto bed leveling sensors working and I have to say I'm loving it.
We are using a capacitive sensor since it's supposed to work with glass beds better. I print directly on glass and really haven't had any kind of issues with adhesion.
Sensor : LJC18A3-H-Z/BX Make sure is is the NPN NO (normal Open type).
If you are not using glass, or pei, you can look into using an inductive sensor. The trade off is that you might need to adjust the offset for a capacitive sensor as it is supposed to vary a little bit due to heat and humidity.
Firmware : Skynet 2.3 https://www.facebook.com/search/top/?q=skynet3d firmware development
Bracket : http://www.thingiverse.com/thing:1907394
Wiring diagram:
We've found that we are getting better results by powering the sensor with 12 volts instead of 5. The problem with that is that you don't want to feed that 12v of power into the z stop connector on the control board, as that is running at 5v. You don't want to let the magic smoke out.
Darren can probably explain this better, but basically wev'e wired a couple of diodes inline to prevent the 12 volt current from going across the into the signal pin on the control board. When the sensor senses the bed, it closes the connection, and from what Darren tells me this lets the signal get pulled to ground.
All I really know right now is that this works. The guy in charge of skynet claims you can run it off of 5 volts, in which case you could just hook up all 3 wires to the z stop pins on the board. The are also other wiring diagrams that use resistors to create a voltage divider circuit. So far, I've been using this and the magic smoke is still in the board.
Steps:
1) Print a bracket of your choosing.
2) Install the sensor
3) Grab the skynet firmware and flash your control board. It's pretty straighforward and the instructions for doing it are included in the download.
4) Fool around with the sensor to get it to sense your bed. You can use a combination of adjusting the height of the sensor in relation to the nozzle and turning the set screw on the sensor to adjust it's sensitivity.
5) Use the z control buttons on your favorite printer control software to adjust the nozzle down to where it squishes a piece of paper just right. Just like you did when you used to level your bed manally.
6) Record that offset (should be a negative number. Mine is -1.45 right now) and enter that into the printer as the z-offset.
Thats pretty much it. You can level the bed on the printer using the lcd screen and the buttons to select it, but what I've done is to just add the bed leveling as part of my start script. It gets prepended to any gcode that I send to the printer.
Here's what I have my starting script set to in Simplify 3d. Just like you probably already use the G28 to home everything, G29 will run the auto bed level. Skynet is defaulting to a 9 point level, which might be overkill. I know darren changed the config for his firmware to do a 4 point level. I just like to watch the sensor fly around the bed before it prints.
You can see some other extra commands I have in there that basically prime the nozzle by running a couple of lines along the y axis to get things ready to roll.
Code:
G28 ; home all axes
G29; auto level bed
G1 X20 Y5 Z0.2 F3000 ; get ready to prime
G92 E0 ; reset extrusion distance
G1 Y150 E20 F600 ; prime nozzle
G1 X25 Y5 Z0.2 F3000 ; get ready to prime
G92 E0 ; reset extrusion distance
G1 Y150 E20 F600 ; prime nozzle
Here's a print I did using the wood fiber filament of a buddah body with a baby groot head. The filament feels a little bit like balsa wood, probably because I printed this with only 10% infill, so it is really light. But it seemed to print pretty well actually.