u/yw_1820

Filament stops mid-print on my secondhand K1C — think it might be heat creep?

Hey everyone, hoping to get some advice.

I bought a used Creality K1C a while back and it printed fine at first. Lately though, filament extrudes normally for a while into a print, then just... stops. No more flow, print fails.

What I've tried so far:

Replaced the nozzle

Did a quick filament load test right after installing the new nozzle — filament extruded perfectly fine

Since the short load test worked fine but it still fails partway through actual prints, I don't think it's a simple clog anymore. My best guess right now is heat creep — maybe the heatsink cooling fan isn't running at full strength (or the duct got misaligned when I had the hotend apart before), so heat slowly creeps up into the cold zone above the heatbreak during a longer print, the filament softens too early, expands, and jams.

Does this sound like the right track? A few things I'm planning to check:

Whether the heatsink fan is actually spinning at 100% during prints

Whether the fan duct is still aimed correctly at the heatbreak fins

Dust buildup on the fan/heatsink (it's secondhand so who knows what the previous owner did)

Would appreciate any input from anyone who's dealt with this on a K1C (or similar direct-drive hotend) — especially if there's something else I should check before assuming it's heat creep. Thanks!

u/yw_1820 — 1 day ago