Project Dashboard Maintenance and Repairs TAZ Aerostruder Hotend Replacement Workflow

1 Gather Materials

  • Tool head that needs a new hotend
  • Replacement hotend assembly [KT-HE0006]
  • 2.5mm hex key
  • 2.0mm hex key
  • 1.5mm hex key
  • Wire clippers
  • Pin removal tool

2 Remove limit switch

Using the 1.5mm hex key, loosen and remove the two fasteners that hold the limit switch into place.

Location of fasteners in green
Loosening the fasteners

3 Remove the blower fan and duct

Using a 2.5mm hex key, loosen and remove the single fastener next to the heatsink fan.

Using a 2.0mm hex key, loosen and remove the fastener above the blower fan and the one right below it on the blower fan.

Carefully remove the blower fan and duct away from the part, it will still be connected by the fan wiring harness.

The 2.5mm fastener in blue and the two 2.0mm fasteners in green
Removing the 2.5mm fastener
Removing the 2.0mm fasteners
Fan duct separated from the toolhead

4 Cut zip ties

Using a set of wire clippers, carefully cut the zip ties holding the wires on the back of the tool head.

Careful when cutting the zip ties, you don't want to damage the wires.

5 Remove the heatsink fan

Using the 2.5mm, loosen and remove the four heatsink mounting screws and remove the fan duct by sliding down off the bottom of the tool head.

The four fasteners in green
Removing the fasteners

6 De-pin the heater

Using the pin removal tool, carefully remove the pins for the heater.

Note: this step is only required if the hot end assembly needs to be replaced.

Compress the latch and slowly remove each heater wire

7 Disconnect the thermister

Depress the retention tab on the connector housing and disconnect the thermistor extension. At this point, the hot end assembly can be lifted and removed.

Thermistor Disconnected

8 Remove the hotend and heatsink assembly

Using the 2.5mm hex key, loosen and remove the four fasteners holding the hotend assembly in place.

Remove the assembly by wiggling and pulling. Loosening the idler compression screw can help. Turn clockwise to decompress the spring.

If there is still filament stuck in the hot end, you will need to wiggle the filament guide loose from it.

The four fasteners in green
Removing the fasteners
Removing the filament guide from the filament

9 Inspect the extruder mechanism

Inspect the bearings, hobbed shaft, idler arm, guide tube, and drive gears. Clean as necessary.

The inside of the extruder

10 Transfer the bearing

Remove the bearing from the old heatsink and install it in the new heatsink. A spare stepper motor shaft is a good tool to remove the bearing, just push the shaft into the bearing and then wiggle and pull the bearing out.

Bearing being removed from the old extruder
Removing the bearing.
Bearing being installed in new unit.

11 Re-assemble

Reassemble the toolhead as shown observing the following:

Take care to not pinch any wires when installing the new heatsink assembly.

The red ground wire goes thought the heatsink fins and on the bottom left short fastener.

The fan must be up on the heatsink before the fan duct is installed so that the wires are routed correctly.

Both heater pins go with the latch facing outwards.

The heater and thermistor wire pairs are not polarized.

For more details, see the Assembly OHAI

Installing the new hotend. Important to note the red wire goes on the lower left
Installing the heatsink fan
Installing the blower fan and duct
Re-pinning the heater wires
Re-connect the thermister
Installing the limit switch
Installing new zip ties
Job complete
Done! Take me home