Update 8/2/2026: This article has been updated with the official statement made by Prusa on r/prusa3D.
Bondtech, the inventor of the INDX toolchanger system used to create the highly anticipated Prusa CORE One+ INDX, admitted to a significant mistake. The nozzles, which are nitrocarburized steel, do not meet industry standards for “hardened steel” as advertised.
Prusa Research has pumped the brakes on the INDX project, and has delayed shipping INDX conversion kits until mid-August. They issued a statement on Reddit:
“Bondtech has recently confirmed that the nozzles currently supplied with the INDX system are surface-hardened rather than fully hardened as originally planned, and has not yet finalized the compensation plan for affected customers. We believe it is better to wait until both we and you have clearer information, rather than ship the kits while this important question remains unresolved.”
The statement was also emailed directly to everyone with an active INDX order in the system. The company said this delay will also give customers a chance to cancel their orders if they wish. As an olive branch, Prusa Research INDX conversion kits will included extra hardware free of charge. The statement didn’t say what the gift would be, but that specifics would be shared before shipping.
Prusa engineers immediately began testing the INDX nozzles and determined that little wear could be seen after running five kilograms of carbon fiber PETG through the nozzles. However, after just 100g of super-abrasive Ultraglow filament, the protective coating began to fail.
Nitrocarburized steel is tougher than the standard brass nozzles that come with a stock Prusa CORE One+, but not as durable as hardened steel. The real problem is not that they went with a lesser nozzle, but that they kept the “hardened steel” wording in promotional materials. If Bondtech said from the beginning (or before customers locked in their pre-orders) that the INDX shipped with ordinary steel nozzles, no one would have blinked.
Information on the nozzle quality began to surface after a Reddit user posted a support email from Bondtech founder, Martin Bondeus. The email stated that “during production, we encountered manufacturing challenges that prevented us from machining that material reliably – the cutting tools simply did not withstand the process. Rather than releasing a product with inconsistent quality, we decided to supply the nitrocarburized version for the time being.”
These nozzles are not of poor quality, but they fall short of the standards set for hardened steel. According to a statement by Bondtech, the Founders Edition shipped with nitrocarburized steel, which is steel treated to obtain a hard shell. They’ve batch tested the nozzles and found them to be around 30-32 on the Hardness Rockwell C scale (HRC). For comparison, true hardened steel lands at 55-60 while an everyday brass nozzle comes in under 10 HRC.
For most users, and most materials, these mid-tier steel nozzles work exceptionally well and will last for an extremely long time. But once you start to feed your INDX abrasive filaments like glass-fiber, carbon-fiber, glow in the dark and metal filled filaments, things get dicey. The treated steel nozzles will last longer than brass, but Bondtech said they will experience “accelerated wear” when printing abrasives.
Bondtech has stated on its website that a “concrete solution” to the problem is not ready and that manufacturing truly hardened INDX nozzles could take months. They are also not offering any form of compensation before knowing the cost of the replacements. They are requesting that customers hold off on returning the kits and simply enjoy using non-abrasive materials until a solution is found.
The INDX takes a bespoke induction heated nozzle that has no off the shelf replacement at this time.
The news has hit the Founders Edition buyers quite hard, as many have already found difficulty with the kits they so eagerly purchased months ago. Some assembly problems can be expected with such a product, as they are being mounted on CORE One printers already in service. The INDX is a separate upgrade kit, and it requires stripping down a CORE One, removing the Nextruder and replacing it with the INDX carriage, then mounting a rack to hold the eight tool heads.
One “founder” was so upset he vibe coded an entire website in protest: Nozzlegate.com. The website outlines what the perceived problems are with Bondtech, and what consumers can do about it. We contacted the website owner, who asked to go by his handle “Daddie0.”
He told me that, like others who purchased Founder Edition kits, he’s disappointed in the quality of the product. He said his INDX was suffering from multiple mid-print crashes and layer shifts, and after two weeks of troubleshooting, it was finally fixed with a firmware update from Prusa. “Then nozzlegate hits. My EU right-given two-week return window ends a day after the news breaks.”
Realizing that his window for a standard, hassle-free return had closed on a machine he felt was a lemon, he shifted strategies. He began digging into Bondtech’s official documentation to see what recourse he had for a defective product.
What he found sparked a new battle. Disagreeing with Bondtech’s listed 90-day warranty policy, which he claims misleads consumers by failing to mention Sweden's mandatory multi-year consumer protections, he channeled his frustration into the NozzleGate website.
The INDX kit is a collaboration between Prusa Research and Bondtech, with the first wave of Founders Edition kits a limited edition run going to early adopters.
Tom’s Hardware received a Founders Edition INDX kit, which we installed on a Prusa CORE One we previously reviewed. Though the build took over the kitchen table for an entire weekend, our resulting INDX is printing non-abrasive filaments with excellent quality.
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