A customer of ours provided this method for replacing the V4 hotend heatbreak on the MakerGear 3D printers.
Please note: a new nozzle is recommend when installing a new barrel. Here is what MakerGear says:
"Once a new nozzle has been installed onto a barrel, do not install that same nozzle onto a different barrel or leakage may occur. As you install a new nozzle onto a barrel, a small amount of material is removed from the nozzle to create a custom fit. This makes the nozzle incompatible with any other barrel due to the slight variations in tolerances among different barrels."
Note: Always unplug your printer and wear proper safety gear.
Remove old barrel:
- Disassemble the hot end; remove the fiberglass sleeve, heater and thermistor from the block
- Rapid heat the aluminum block (propane torch works perfect). Do not heat too long, the idea is heat the block quickly without overheating the barrel
- Push the old barrel out (light tap may be needed). This needs to be done quickly after heating.
- Clean the aluminum block of residual plastic and/or of other contamination
Replace new barrel:
- Place the barrel in the freezer for 20-30 minutes. This causes the barrel to dimensionally contract a small amount.
- Keep the barrel in the freezer until ready to insert in block (have it easily accessible)
- Rapid heat the aluminum block (propane torch works perfect)
- Quickly retrieve the barrel from the freezer and drop it in into the block, it should seat on its own. This needs to be done quickly before the block cools.
- Set aside and allow the parts to stabilize to room temperature before handling.
- The barrel should now be in a tension fit… aka should not spin when mounting the nozzle.
- Reassemble the hot end as required