Creality Mk8 Hotend Captive Heatbreak Liner Mod

thingiverse

This modification completely reverses the known issue with the Creality hot end where PTFE tubing slips in the Bowden fitting and creates a small gap between the tube's end and the nozzle, often causing partial or under extrusion issues. This is the most common cause of these problems. The mod takes a short length of your stock PTFE tube and locks it in place within the heat break so that this gap can never form again. You can still perform nozzle changes exactly as before, and by using higher performance tubing you can get reliable printing at higher temperatures with your stock hotend. Since the temperatures are low at the top of the heatsink, PLA is perfectly adequate for making the spacer. Image 1: Shows everything you will need - the stock hotend with its Bowden fitting removed, a piece of PTFE tube, and the spacer. Image 2: Push the tube into the hotend until it reaches the nozzle. Mark the top of the heatsink on the tube. Make sure that the end of the tube contacting the nozzle is flat and square so an effective seal can be made. Image 3: Use the threaded part of the Bowden fitting to gauge another mark closer to the nozzle end of the tube, then cut the tube at this new mark using a sharp knife. Image 4: Fit the spacer over the freshly cut end of the tube. Image 5: Insert the tube and spacer into the hotend. Image 6: Screw the fitting into the top of the heatsink only finger tight. Any tighter might cause the tube to be pinched by the filament, so use a drop of Loctite on the threads if you want added security. Attach the hotend and Bowden as usual. This is a prototype modification, but it does work. I appreciate any feedback or reports of long-term issues. Please note that there may be many different heat sink designs from Creality, some with not enough distance between the top of the heat break to fit the spacer in properly. You should be able to screw the fitting into the heat sink about 5mm deep. Any less will likely cause problems. Check out the work by Luke Hatfield who has developed something similar. Choice is always a good thing! https://www.thingiverse.com/thing:3203831