Prusa CORE One kits face nozzle flaw, raising print quality concerns

Prusa CORE One kit buyers ran into a nozzle problem that can look like slicer trouble but starts at the hot end: soft steel nozzles tied to Bondtech and machining flaws that Bondtech has said do not have a quick fix. For a printer that sits in the premium end of the hobby, that is not a cosmetic defect. It is the kind of issue that can throw off extrusion consistency, wear resistance, and the ability to run abrasive materials without chasing ghost settings.

In practice, a bad nozzle can show up as rough first layers, uneven line width, inconsistent flow, or prints that fail even after temperature, retraction, and flow tweaks. That is why CORE One kit owners are being pushed to inspect the nozzle itself before they burn more time on calibration. If a print suddenly behaves as if the machine is under-extruding, dribbling, or changing line width from one pass to the next, the nozzle is one of the first parts to examine for wear or machining problems, especially if the machine is expected to handle filled or abrasive filaments.

The issue landed hard in a community that had already been watching Prusa and Bondtech’s INDX work closely. Bondtech describes INDX as a tool-changer solution for multimaterial 3D printing, and Prusa forum results show founders edition INDX units for the Core One were expected to ship in January 2026, with 1,200 available and all reserved. That made the nozzle quality question bigger than a single bad part: early buyers were effectively being asked to trust a premium ecosystem built around a component that should be mechanically dependable from the start.

Discussion moved quickly through the Prusa3D Forum, including a thread titled “INDX #nozzlegate follow up & communications,” where Tommy from Prusa was referenced in a follow-up post. A community video posted on July 24, 2026, titled “The Surprising Truth About the INDX's Nozzles - PrintFixFriday 254,” showed the nozzle controversy had already become a broader maker-topic, not just a support ticket.

Bondtech’s broader catalog makes the stakes even clearer. The company sells upgrade kits, extruders, nozzles, and hotends for FDM printers, and its nozzle category includes parts from Bondtech, Slice Engineering, and 3D Solex. When a machining or hardening problem hits that part of the stack, it can look like a firmware bug or a bad profile until a user realizes the metal at the tip was never right. That is the headache at the center of this one: a tiny nozzle, and a very expensive amount of print quality riding on it.