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Heat-Break Replacement and Extraction

Over time, heat-breaks can become bent or damaged due to tool collisions from improper calibration, or when performing other maintenance on the hot end. While we recommend replacing the entire hot-end assembly in the case of damage, repairing individual components may be done at the operator's risk. The repair and extraction process for the heat-break can be either extremely easy or fairly difficult depending on how tight the hot-end assembly was installed, how much the filament "grips" the sidewalls of the heat-break and nozzle, and whether or not the heat-break has snapped entirely. If the heat-break you want to replace is still in one piece, is bent, or simply requires replacement, continue reading below. If the heat-break has snapped completely, you will want to read the advanced replacement directions here.

While working on the machine tools inside the machine, you must lower the bed to a comfortable working height to gain access to the underside of the carriages. After homing, you may run the G-code command G0 Z200 in the terminal, or use the directional controls on the control page of the user interface.

Note

If you have your filament fed from spools inside the chamber, make sure they are clear from collisions with the bed before moving the bed down!


Basic Heat-Break Replacement

You will need...

  • M7 socket or wrench (for the nozzle)
  • vice-grips
  • adjustable wrench

Begin by heating the hot end to the extrusion temperature for the last filament used and retract the filament that may remain in the heat-break, then let hot end cool fully. Alternatively, you may wish to cut the filament above the extruder motor if you intend to discard the lower section of the heat-block assembly.

Warning

While performing any maintenance on the printer, ensure it is powered down and cooled sufficiently. Always verify that hot-ends are no longer hot with a non-contact thermometer before touching with bare hands.

Next, disconnect the wires for the heating cartridge and temperature sensor at their connectors. Attempt to unscrew the entire hot-end assembly in one piece by holding onto the heat-block. The heat-break should unscrew from the cylindrical cooling-block.

Holding the heat-block tight with vice grips, loosen the nozzle slightly - this will make heat-break removal easier as the two parts are butted together inside of the heat-block. Carefully remove the heat-break from the top of the heat-block using either your hands, or a pair of pliers or vice grips if it is held in tightly.

Replace the heat-break with a new one and screw it in until the neck lays flush with the top of the heat-block. Re-tighten the nozzle, ensuring that the heat-break remains stationary, then screw the entire hot-end assembly into the cooling-block. Re-attach the connectors for the heating cartridge and temperature sensor.

If during this process, the heat-break snaps, you will need to proceed through the advanced heat-break repair which is slightly more involved. You will require a screw-extractor kit to remove the heat-break (4mm or imperial equivalent).


Advanced Heat-Break Replacement

You will need...

  • vice-grips
  • screw-extractor kit
  • fabric tape or small cloth/rag
  • bucket
  • phillips screwdriver
  • fortitude

Extraction from the Heat-Block

Begin by disconnecting the wires for the heating cartridge and temperature sensor at their connectors as described in the basic heat-break replacement instructions. Take extreme care to not break the wires for the temperature sensor.

Clamp the heating-block in a vice, nozzle side up and remove the nozzle from the heating-block (it may be tight due to solidified plastic). Flip the heating-block in the vice so it is heat-break side up. Attempt to remove the heat-brake using a small phillips screwdriver that you don't mind possibly marring. If this is unsuccessful, proceed to using a screw-extractor kit, and remove the remains of the broken heat-break using the method specified by your screw-extractor kit.


Extraction from the Water-Cooling-Block

To remove the broken top-section that may remain in the water-cooling-block, you will need to follow a similar process to removing the heat-break from the heat-block. Begin by loosening the set-screw on the side of the probe collar with an M2 driver. Slide the water-cooling-block assembly downwards and out from the probe collar.

As with the heat-block, attempt to remove the remaining portion of the heat-break using a phillips screwdriver or pliers if there is enough stick-out remaining to grip. If unsuccessful, you must proceed to removing the cooling block, and using a screw-extractor kit to remove the remaining section of the broken heat-break.

Using strong clamps or two pairs of vice-grips, clamp down on the two coolant hoses leading into the water-cooling-block, using a small rag or fabric tape to protect the hosing from the clamp jaws. Take note of the hose positions and make marks with a permanent marker so the inlet and outlet hoses are in the same place when re-attaching later. Next, loosen the hose clamps at the cooling block and remove both hoses, taking care to catch any leaking coolant in a bucket.

Note

There will be coolant in the cooling block. Remember to rotate it and drain as much as you can before walking to your bench!

Once separated from the machine, you may attempt to remove the remains of the heat-break with your screw-extractor kit, then replace the cooling-block in the reverse order. Take care to bleed the air that has been introduced into the system by opening the cooling loop, and top off the coolant reservoir if required.

Warning

When re-attaching the water-cooling-block to the probe collar, ensure that the hose clamps do not interfere with vertical probe travel!