Project Dashboard Maintenance and Repairs Mini 2 Aerostruder Hotend Replacement Workflow

1 Gather materials

  • Aerostruder Tool Head that needs a new hot end
  • Replacement hotend assembly [KT-HE0008]
  • 2.5mm hex key
  • Some sort of tool with a small point (Pin removal tool works well:

2 Remove the heatsink fan

Using the 2.5mm hex key, loosen and remove the four M3 screws that hold the fan onto the heatsink.

Location of fasteners in green
Heatsink fan removed
Heatsink fan removed

3 Remove the blower fan and duct

Loosen and remove the four heatsink mounting screws and remove the fan duct by sliding down off the bottom of the toolhead.

Location of mounting screws in green

4 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.

Latch side up, two heater pins in green circles
Probe both sides and pull firmly on the lead

5 Disconnect the thermistor

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

6 Remove the hotend-heatsink assembly

Remove the heatsink assembly. Loosening the idler compression screw can help. Turn clockwise to decompress the spring.

Remove filament guide from filament if necessary

7 Inspect the extruder mechanism

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

Specifically, look for plastic or worn teeth on the hobb, cracks or wear on the idler or guide, or excessive wear or missing teeth on the drive gears.

8 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 removed from old unit
Bearing installed in new unit

9 Re-assemble

Reassemble the toolhead as shown observing the following:

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

The fan duct must be installed before the two bottom M3 screws can be installed.

The red ground wire goes thought the heatsink fins and on the bottom right M3 screw.

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

The short M3 screw goes in the bottom left hole.

Both heater connectors go with the top of the U shaped crimp facing the triangular latch of the connector.

The heater and thermistor wire pairs are not polarized; the order of the wires can be switched without affecting function.

For more details, see the Assembly OHAI

Make sure all the extruder parts are in place
Carefully install the heatsink
Order of fasteners
Put the fan up before putting the duct on
Fan duct in place
Ground wire placement
Lower fasteners installed
Reconnect thermistor
Wrap heater wires
Connector detail
Orientation of pin
Orientation of second pin
Fan attached
Done! Take me home