Safety Cutoff Kit 1

The MakerBot Safety Cutoff Kit is a small kit designed to cut power to the heater in case of a catastrophic failure.

Kit Contents:

1 - 1 Green Printed Circuit Board (PCB) with white printing on top
2 - 1 large blue 120 ohm resistor, R4
3 - 1 small resistor brown-black-red bands 1K, R1
4 - 1 small resistor brown-black-orange bands 10K, R2
5 - 1 small resistor blue-gray-red bands 6.8K, R3
5 - 1 black relay with 8 pins
6 - 3 green, 2 pin connector blocks
7 - 1 red LED
8 - 1 black, SL type 4 pin connector

Assembly Instructions

Remove the tape from the ends of the components. Orient the board with the white printing on top and two large corner holes toward you.

You should see a round circle in the top middle of the board labeled FAULT. Place the LED in this position with the longer lead in the hole toward the edge of the board and the shorter lead in the hole near the flat side of the circle. Confirm that the flat side of the LED matches up with the flat side of the circle printed on the pcb. Bend the leads out to hold in place.


Place the large orange resistor in the square on the lower left hand side of the board labeled R4. Bend the leads out to hold in place with a bit of space between the resistor an the board.


Likewise find the square marked R1 near the LED and insert the resistor with the brown-black-red bands. Bend the leads out to hold in place.

Find the square marked R2 near the LED and insert the resistor with the brown-black-orange bands. Bend the leads out to hold in place.

Find the square marked R3 near R1 and insert the resistor with the blue-gray-red bands. Bend the leads out to hold in place.


Solder the resistors and LED in place.

Place the large black relay with 8 pins in place and solder to board.


Place one of the green terminal blocks in the position labeled GND 12V IN and solder in place
Place one of the green terminal blocks in the position labeled GND 12V OUT and solder in place.
Place one of the green terminal blocks in the positon labeled TEMP CUTOFF and solder in place.


place the black SL type connector in the positon labeled ALERT. Make sure the connector lock faces inward as in the diagram and solder in place.


All done soldering!

Install it in place on your bot!

Now that your board is soldered together, it's time to mount it in place. One good place is the right side of the Z-stage.

There aren't any holes, so we'll have to drill them. Hold the board in place and use a pencil to make the position of the holes.


Then drill (carefully) with an electric drill. You'll use a 3mm bolt, so a 1/8" bit will work well. Vacuum up the sawdust before you continue!


Now just bolt it in place with some 1/8" spacers and M3x16mm bolts and nuts.


And now (very important) install the thermostat. You might have already done this when you build your hot end, but if not, this should go around one of the bolts that holds the retainer plate in place.


Then move down the nut to hold the thermostat against the retainer plate.


Connect it up!

Ok, now let's wire things together.

First, take a length of red/black wire to go to the extruder controller's heater port. Insert it into the cutoff kit's "IN" terminal. Make sure that you line up the ground and 12v inputs correctly. If you haven't installed your electronics yet, just leave enough wire to make it down to the electronics cavity.


Next, connect the thermostat to the "TEMP CUTOFF" port — this one doesn't have any polarity.


Take the wire leads that go to your hot end heater and connect those to the "OUT" terminal. The heater doesn't have any polarity.


Last, plug the 4-pin cable into the header, and snake it down into the electronics cavity.


The other end should connect to the port labeled "E-STOP" on the motherboard.


OK, now you're done. If you've wired everything up correctly, the LED will not be lit. If anything goes wrong, you'll see that light go on and your bot will be stopped automatically.


To test that you've assembled everything right, start heating your extruder hot end, and then disconnect one end of the "TEMP CUTOFF" port. Your safety cutoff should click, the LED should go on, and your hot end temperature should start to drop while monitoring in the control panel from Replicator-G. If that happens, you're good to go!

Unless otherwise stated, the content of this page is licensed under GNU Free Documentation License.