The Solution to Creality K1 Under-Extrusion

The K1 was Creality’s most exciting new 3D model release in years and most reviews were positive, but many owners of early revisions experienced serious under-extrusion problems. Creality did offer an extruder replacement to those people, but it doesn’t seem to be available anymore. Jón Schone of the Proper Printing YouTube channel is one of the K1 owners that didn’t get the replacement when it was still available, so his K1 was pretty much useless. To bring it back to life, he designed a completely new extrusion system for the Creality K1 that fixes under-extrusion and improves performance.

The Creality K1 comes with a direct drive extruder, which is normally a good choice for reliability and consistency. But the original K1 extruder lacked power — probably because the extruder motor was small to keep moving mass down.

One solution would have been to swap that extruder motor out for something more powerful. That might also require an entirely new extruder design. But doing that would have added a lot of weight for the K1 to throw around. That would increase inertia, reducing acceleration and print quality at high speeds. Because the K1 is built for fast printing, such a sacrifice would be unacceptable to most people. Jón’s solution was to switch the K1 to Bowden extrusion, which allows for a very powerful extruder motor and that actually reduces moving mass.

By relocating the extruder and extruder motor to the back of the K1, Jón eliminated most of the weight on the moving extruder carriage. Now it is just the hot end, with the Bowden going into the coupler. That dropped the weight from 155g to 15g. But a beefy Bondtech QR extruder pushes the filament, so under-extrusion is no longer an issue. A low-friction Capricorn Bowden tube and a Bondtech CHT nozzle further improve flow.

Jón’s fix only requires a few 3D-printed parts and fasteners. It will work with many different extruders (not just the Bondtech QR), so users can take advantage of extruders they already have. And the modification is entirely reversible. If a user decides they want to return to a direct drive setup, they can easily do that.

For Creality K1 owners experiencing under-extrusion, this is the perfect solution. It addresses that issue while also reducing moving mass, enabling even faster print speeds. In fact, Jón was able to complete a speed Benchy in just 6:50.