Balance

Note: The Balance is no longer being used with the extruder.

Bill of Materials

Name	Source	Files	Qty
Balance Mount 1	Made	step, drawing	1
Chute for Starve Feeder	Made	step, drawing	1
Container	Made	step, drawing	1
Bucket and Lever	Printed	stl, step	1
Hub	Printed	stl, step	1
Sensor Mount	Printed	stl, step	1
Hex bolt 1-4 in by 1-1-2 in long	Purchased	step	2
Nut 1-4 in	Purchased	step	2
Nut M3	Purchased	step	2
Optical Slot Sensor	Purchased	step	1
Pin	Purchased	step	1
Set Screw M4 by 8 mm long	Purchased	step	3
Socket Cap Screw M3 by 10 mm long	Purchased	step	7
Stepper Motor NEMA 17	Purchased	step	1
Washer 1-4 in	Purchased	step	4
Washer M3	Purchased	step	13

Tools needed for assembly

Item No.	Image	Name
1		Allen Key 2 mm
2		Allen Key 2.5 mm
3		Wrench 5.5 mm
4		Wrench 7-16 in

Making The Parts

Go to Making the Balance Parts for information on how to build the following parts:

Container
Chute for Starve Feeder
Balance Mount 1

Assembly

Assembly Steps

Step 1: Screw a stack of washers into the end of the lever. It may be necessary to tap the hole first though it depends on the print. NOTE: The amount of plastic delivered in each bucket can be adjusted by changing the number of washers on the end of the lever.

Step 2: Put the bucket and lever onto the hub using a sewing pin. The pin may need to be shortened or bent so that it does not crash into the motor shaft. The lever should move freely, but the fit should not be sloppy. If you have to file the lever or hub to make them fit, don't file off too much.

Step 3: Lock the pin into position using two set screws. The holes for the set screws may need to be tapped before inserting the pin. Don't over tighten because they may break the pin.

Step 4: Slide the chute into position on the container. It typically doesn't need to be fastened into place, but a few sheet metal screws would hold it in place if desired.

Step 5: Bolt the container onto the balance mount. Only tighten finger tight as the position will be adjusted during final assembly.

Step 6: Attach the optical slot sensor to the sensor mount. It is not shown in the video, but a male 4 pin header should be soldered to the sensor after it is in place. Make sure the order of the pins matches the order of the wires in the cable that will attach it to the main circuit. If the sensor isn't held firmly in place, a bit of hot glue should suffice.

Step 7: Bolt the sensor mount to the container using M3 fasteners.

Step 8: Put the lever and hub into the container and then bolt the motor into place with the hub on the shaft of the motor. Use the holes in the opposite wall of the container to get the allen key into the heads of the socket cap screws.

Step 9: Adjust the position of the hub so that the lever lines up with the optical slot sensor. Then lock it into position with a M4 set screw.

The balance is now complete.