Prusa's INDX multi-extruder upgrade for the CORE One has just received a pointed public assessment. In a Hackaday write-up published October 12, the site summarized a video from Thomas Sanladerer of Made with Layers that sets out where the system falls short. The most practical complaint for anyone who buys filament outside Prusa's own catalog: the INDX's mandatory start-of-print calibration is built around Prusament, and it broke when Sanladerer loaded a different brand.
The original video, posted to YouTube on October 11 under the title "The Prusa Core One INDX has problems," frames the verdict bluntly in its description: "The INDX does a few things really well, and many things... not at all." FilamentFeed has read the video's title and description and Hackaday's account of it. We have not watched the video, so the specifics below come from Hackaday's summary.
What the INDX Is Supposed to Do
The INDX approaches multi-material printing differently from a single-nozzle filament changer. According to Hackaday, it gives the CORE One eight independent extruders, each using a dual-gear Bondtech drive. In theory that allows multi-material and multi-colour printing with very little purge waste. Prusa claims purge waste of about 0.013 g per colour or material change. Anyone who has watched a pile of purge waste grow beside a single-nozzle machine during a four-colour print will see why that number gets attention.
That is the promise. Sanladerer's review, as Hackaday describes it, is about the gap between that promise and how the system behaves on a real bench with real third-party materials.
Calibration That Only Speaks Prusament
The central problem is calibration. The INDX runs a mandatory calibration sequence at the start of each print, and Hackaday reports that this routine is designed to work only with Prusa's own filament and its specific material properties. The result was an inability to print with Voxel PLA until Sanladerer removed the calibration sequence from the G-code by hand. Hackaday also says the entire print sequence uses the material presets for Prusa's filament, and that this resulted in a failed print.
Disclosure matters here. The video description says it was sponsored in part by VoxelPLA, and the product links in it are affiliate links. That does not make the failure less real. But readers should know whose filament exposed the problem.
The deeper issue is design philosophy. A closed calibration loop tuned to one vendor's materials is easier to engineer and support. It is also a quiet form of lock-in, and it sits awkwardly with the open, tinkerer-friendly image that has long been central to Prusa's brand. Makers who buy PLA by the case from whichever supplier is cheapest, or who run engineering filaments Prusa does not sell, are the users most likely to hit this wall.
Calibration Results That Don't Stick
The obvious workaround would be to calibrate manually and move on. Hackaday reports that this does not work either. Manual calibration results are not saved, even though the printer's display says they have been. That is why the start-of-print calibration is, in Hackaday's words, absolutely mandatory. A printer that reports a successful save and then discards the data is arguably worse than one that offers no manual option at all, because the user cannot tell anything is wrong until the next print misbehaves.
This reads like a software problem rather than a hardware one. Still, it shows how much of the system's day-to-day reliability depends on software that, going by this review, is not yet finished.
A Camera That Can't See
A smaller hardware complaint: the INDX hardware blocks the printer's camera view. Hackaday adds that even peeking into the print chamber by eye is heavily obscured by the assembly that holds the extruders, which makes checking that filament has loaded correctly borderline impossible. On a machine meant for long, unattended multi-material jobs, remote monitoring is not a minor feature. Losing the camera removes one of the simplest ways to catch a failed tool change or a detached part before it wastes hours of print time and several spools.
Measured Against the Competition, and Against Prusa
Hackaday notes that, given the issues in the video, the INDX looks somewhat shaky next to competitors like Bambu Lab's H2C and the Snapmaker U1, as well as Prusa's own XL toolchanger printers. The most pointed comparison is with Prusa's own hardware. In Sanladerer's print test comparison between the XL and the INDX-equipped CORE One, Hackaday says there was no contest: the XL "simply works," whereas the INDX even struggles with some Prusa filaments.
That is an awkward result for Prusa, and it complicates the idea that the trouble is limited to third-party spools. The XL suggests the company already knows how to build a multi-material machine that behaves predictably. The INDX's problems may therefore reflect the immaturity of a new product line rather than a fundamental limit of the approach, though that is our reading, not Hackaday's.
Where the Firmware Stands
Prusa's most recent INDX firmware is version 6.9.2. Its release notes appear in the Prusa-Firmware-Buddy repository's release feed dated October 7, four days before Sanladerer's video went up. It is a stable release that runs only on the CORE One+ (Gen 2) INDX and the CORE One/+ INDX. Its headline change adds on-printer filament presets for PVA and BVOH. According to the notes, these presets were announced in the previous release but left out because of a process error.
Nothing in the 6.9.2 notes, as published, addresses third-party filament calibration, the unsaved manual calibration values or the camera. The release does show that on the INDX, filament presets are delivered through firmware, which fits the preset-driven behaviour Hackaday describes.
What It Means for Makers
If you already own a CORE One and mostly print Prusament, the INDX may serve you well. Low claimed purge waste and eight independent extruders are real advantages, and at least some of the problems Sanladerer describes, such as the unsaved calibration values, look like things software could fix. Hackaday, though, says the INDX struggled even with some Prusa filaments.
If you rely on third-party filament, read this review before ordering. On the evidence Hackaday reports, getting non-Prusa material through the mandatory calibration meant editing G-code. You also cannot fall back on manual calibration, because the results are not saved. That is a reasonable task for an experienced user, but it is not what most buyers expect from a premium upgrade.
And if you are choosing a multi-material machine from scratch, the review's most useful finding may be the XL comparison. Prusa already sells a machine that, in this test, simply works.
FilamentFeed will follow Prusa's next INDX firmware releases for any changes to calibration behaviour and third-party material support.
