Extruder Body

Note: The hopper on the Extruder Body has been eliminated. In the new design, the small hopper seen in the photo above is part of the Drying Hopper.

Bill of Materials

* Denotes that the item is included in the kit.

Name	Description	Source	Files	Qty
Barrel*	Make from 0.5 in ID DOM steel	Made	step, drawing	1
Breaker Plate*	Make from 1/2 in aluminium bar	Made	step	1
Cooling Tube*	Make from 3/8 in OD 1/4in ID brass tube	Made	step, drawing	1
Feed Throat*	Make from 0.5 ID DOM Steel	Made	step, drawing	1
Flange*		Made	step, drawing	1
Heater Zone 3*	Make from fiberglass insulated nichrome wire.	Made	step	1
Heater Zone 4*	Make from fiberglass insulated nichrome wire.	Made	step	1
Heater Zone 5*	Make from fiberglass insulated nichrome wire.	Made	step	1
Hex Bolt 9-16 in by 1 in long*	Can be a bit difficult to find. Could be made on lathe.	Made	step, drawing	1
Nozzle*	make from 1/2 in brass rod	Made	step, drawing	1
Heating Tape 1-2 in x 24 in 104 watt*	briskheat.com BIH051020L or BIH052020L depending on voltage	Purchased	step	2
Merchant Coupling 1-2 in*	This type of coupling has straight (NOT TAPERED!) threads all the way through.	Purchased	step	1
Pipe Insulation - High Temp*	High temp insulation e.g Owens Corning	Purchased	step	1
Set Screw M4 by 8 mm long*		Purchased	step	3
Ship Auger 1-2 in by 18 in long*	WoodOwl.com recommended for larger 7/16 in shank size.	Purchased	step	1
Socket 7-16 in*	Pick size to fit auger shank. 3/8 in drive.	Purchased	step	1
Socket Cap Screw M3 by 16 mm long		Purchased	step	1
Thermistor*		Purchased	step	5

Tools needed for assembly

Item No.	Image	Name
1		Allen Key 2 mm
2		Allen Key 2.5 mm
3		Pipe Wrench
4		Wrench 11 mm
5		Wrench 13-16 in
6		Wrench 8 mm

Making The Parts

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

Flange
Feed Throat
Barrel
Breaker Plate
Nozzle
Hex Bolt 9-16 in by 1 in long
Cooling Tube
Heater Zone 3
Heater Zone 4
Heater Zone 5

Assembly

Assembly Steps

Note: The extruder body must be partially assembled a few times in order to determine the locations for various holes and cuts. Thus the assembly video is a bit mixed with the instructions for making the parts. Follow the making the parts section for each part until they reference a particular step in the assembly video.

Step 1: Use pipe wrenchs to couple the floor flange, 1 inch nipple, 1 to 1/2 in. reducer, feed throat, merchant coupling and barrel. Make sure all joints are tightened town to their final locations.

Step 2: Layout and drill the holes for the following:

The spring pin that secures the floor flange to the 1 in. nipple.
The spring pin that secures the reducer to the 1 in nipple.
The hole in the reducer that will take an M4 set screw and lock it to the feed throat. Make sure the hole only goes part way into the feed throat.
The holes in the merchant coupling that will lock it to the feed throat and the barrel. Make sure the holes only go part way into both the feed throat and the barrel.

Step 3: Layout the location of the opening in the feedthroat using a scribe. If it is practical for you, the opening can be cut out at this time. Otherwise cut the opening later on at step 10.

Step 4: Add the spring pins to the holes securing the floor flange and the reducer to the 1 in nipple.

Step 5: Uncouple the barrel, merchant coupling and feed throat from the other components.

Step 6: Tap the hole in the reducer with an M4 tap.

Step 7: Tap the holes in the merchant coupling with an M4 tap.

Step 8: Open up the blind hole in the barrel to 4mm so that it can accommodate the set screw.

Step 9: Open up the two blind holes in the feed throat to 4mm so that they can accommodate the set screws.

Step 10: Cut the opening into the feed throat. This can be done with an angle grinder and a flat file but is probably easier to do on a milling machine if available.

Step 11: Assemble a hacksaw with the blade going through the feed throat. Then cut 6 evenly spaced grooves running the length of the feed throat. Cut the grooves at least 0.5 mm deep and do your best to keep them even.

Step 12: Reassemble the feed throat, merchant coupling and barrel onto the other components. Tigten until the holes for the set screws come into alignment.

Step 13: Lock the feed throat and barrel into place by inserting the 3 M4 set screws into their holes and tightening.

Step 14: Attach the hopper using the t u bolts.

Step 15: Tighten the 9/16 in. hex bolt into position on the barrel. Make sure it is good and snug, but don't strip it. Then screw the cooling tube into the hex bolt. Again screw it it until is is nice and tight. It should still be straight at this point.

Step 16: Mark the top edge of the cooling tube. This will be used for alignment during bending.

Step 17: Remove the cooling tube and the 9/16 in hex bolt as one piece. Then bend the cooling tube to the angle indicated in the drawing. NOTE: Make sure that the bend is in the correct direction with the mark on the top of the cooling tube on the outside of the bend.

Step 18: Attach the nozzle to the cooling tube.

Step 19: Attach the thermistor for heating zone 3 using kapton tape.

Step 20: Wrap the heater for zone 3 around the cooling tube and secure it into place with a layer of Kapton tape. Wrap a piece of motor wire around each end of the heater wire and twist the ends to add some extra support to the Kapton tape. Finally, add some kapton tape to gather the thermistor wires and heater wires together. This will add some extra strain relief.

Steps 21-24: Repeat steps 19 and 20 for heating zones 4 and 5.

Step 25: Screw an M3 x 16mm into the breaker plate. Then insert this into the barrel with the head oriented upstream and the threads pointed out.

Step 26: Attach the cooling tube back on to the barrel. Add a bit of copper anti-seize compound to the threads to keep them from getting loaded with plastic and binding.

Step 27: Attach the thermistor for heating zone 1 on the top of the barrel using Kapton tape.

Step 28: Wrap the heater for zone 1 into place making sure that it passes directly over the thermocouple. Secure it by wrapping and tying the fiberglass strings at each end. Note: Be careful with the fiberglass strings they aren't super strong.

Steps 29-30: Repeat steps 27 and 28 for heating zone 2.

Step 31: Put the insulation for the barrel into position with the length wise slit on the top. This will allow the wires from the heaters and the thermistors to exit the insulation. You may need to make a few small cuts in the insulation wrapper to accommodate the wires. Tape the insulation into place using Kapton tape. NOTE: The fiberglass insulation is irritating. Use silicone gloves while working with it and avoid breathing any dust given off.

Note: The ship auger and the 7/16 in socket will be put in place during the final assembly when the extruder body is attached to the gear box.

The extruder body is now complete.