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Assembling a Hot End and Wade's Extruder

27 February, 2012 

Wondering which Barrel, PTFE Rod and Nozzle to use?

The size of the hole in the PTFE Rod and Brass Barrel needs to match the filament you intend to use. If you try to use 1.75mm filament in a 3mm hole, it can buckle and twist and cause jamming which is can be frustrating to remove. 1.75mm is being used more and more as it can give better print output. Each time the extruder nozzle needs to stop at the end of one run and jump across to print a layer on another position, it can leave a "spider web", a thin thread of plastic. This becomes messy over time, so the software tells the stepper motor to reverse a couple of steps to stop the plastic coming out justs before the end of the run, and then step it forward again just before the next run starts. This will be more accurate with a 1.75mm filament. 3mm filament is thicker and so less flexible when being unrolled into your machine.
A smaller nozzle (such as 0.34mm) gives a more accurate printout and can allow smaller layer heights, but if you want lots of plastic to come out, because you are printing larger objects (at least the full size of your print bed) or want to do a lot of printing, then try a 0.5mm nozzle


Assembling a Hot End

Heater Block
Heater Block
Heat Resistor
Heat Resistor
Thermistor
Thermistor
Brass Barrel
Brass Barrel
PTFE Tube
PTFE Rod
Cable
Cable
6mm Kapton Tape

6mm Kapton Tape
Heat Conductive Paste
Heat Grease
Solder leads onto the Heat Resistor and THermistor Step 1: Take a 100K Thermistor and a heat resistor and solder wires to each end. You should use a heavier gauge wire than that shown for the heat resistor, such as speaker wire as it has to carry lots of current.
Put Kapton Tape over the leads Step 2: Completely cover the leads and joins with kapton tape, but do not cover the body of the part.

Barrel and Sleeve Assembly Step 3: Prepare the Aluminium Heater Block, Nozzle, Brass Barrel and PTFE Tube.
The PTFE Tube should be bored out with a 5mm drill about 20mm deep into one end, then Tapped with an M6 tap to accept the barrel. This step may already have been done for you depending on whether you bought just the part, verses a kit from us.
Barrel and Sleeve Assembled Step 4: Screw the Barrel into the PTFE Tube, then spin the Aluminium Block onto the Barrel, and put the Nozzle onto the Barrel.
Then spin the heater block back down the barrel until it is tight against the Aluminium Block
Completed Hot End Step 5:Smear each part with Heat Grease - it helps to make sure the part is in complete thermal contact with the Aluminium Block.
Slide the Heat Resistor and Thermistor into the Aluminium Block. Some people then pour epoxy resin into the holes from each side to hold them in place. We suggest using Kapton tape to wrap around the short sides of the block, at least until it is all tested and working.


Congratulations! your Hot End with PTFE thermal barrier is now ready to attach to the Extruder of your choice.

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Assembling a Wade's Extruder

These instructions will also work for other similar extruders such as Greg's extruder. The principle of the sprung shaft and bearings used to pinch the filament is also used in Adrian's Extruder and the mini universal extruder.
Hobbed Bolt
Hobbed Bolt
608 Bearing
608 Bearing
Nema 17 stepper motor
Nema 17 Stepper Motor
Idler on Hobbed Bolt Step 1: Push the large plastic idler gear onto the M8 Hobbed Bolt
Pressure Plate Parts Pressure Plate Step 2: Push the short shaft into the plastic housing, inserting the 608 bearing in the centre.
Extruder Body Step 3: Push 2 608 bearings into the extruder body - on each side.
Pressure Plate Bolts Assembled Bolts Step 4: Assemble washers and pen springs onto 45mm long M3 bolts.
Pressure Plate Bolts Assembly Step 5: Thread bolts through the assembled Pressure Plate and Extruder Body and add nuts.
Extruder Mounting bolts Step 6: At this stage it is a good idea to add the M5 Extruder Mounting bolts, washers and nuts. The later become obscured by the stepper motor and pressure plate.
Extruder Motor Mounting Step 7: Mount the stepper motor to the extruder body using 4 x 10mm M3 screws. Start with the motor almost all the way toward the pressure plate. You will have to back and forth the next few steps until you get the position right as when assembled the idler gear obstructs the left two screws.
Extruder with Hobbed Bolt Step 8: Insert the hobbed bolt with idler gear.
Extruder Assembled Step 9: Add the (small) drive gear and tighten the grub screw.
Extruder Complete Step 10: Wriggle the PTFE tube of the hot end into the extruder body. Use a small self tapping screw to fix the hot end to the body.
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