Bondtech INDX Upgrade for Prusa CORE One+ | Everything you need to know

Hold one of the eight INDX tools in your hand and the strange thing about it is what is missing. There are no wires. No power cable for a heater, no thin sensor wires, no plug of any kind. It is just a small metal nozzle with a holder around it, and it weighs almost nothing.

It sits in a rack inside the printer, stone cold, while the machine prints with a different one. Then the printer picks it up, and about twelve seconds later that cold nozzle is hot and printing.

That one idea is what the Bondtech INDX is built on, and it is why a printer many people already own, the Prusa CORE One+, suddenly became one of the most interesting machines of 2026 without Prusa launching anything new.

Before the details, though, it helps to be clear about what problem this thing is solving. If you already know how multi-colour printing works today, skip the next section. If you do not, none of the rest will make sense without it.

How multi-colour printing works today, and why it wastes so much plastic

A normal 3D printer has one nozzle. Filament goes in, it melts, it comes out through a hole about 0.4 mm wide, and the printer draws your object line by line.

One nozzle means one material at a time. So if you want a second colour, something has to swap the filament for you. That is what a Bambu Lab AMS or a Prusa MMU3 does. It is a box that holds a few spools and feeds whichever one the printer asks for.

Here is the problem with that. When the printer switches from black to white, the old black plastic is still sitting inside the hot nozzle. If it just carried on printing, the first bit of white would come out grey. So the printer pushes fresh white filament through until all the black is flushed out, and it dumps that mixed plastic somewhere off to the side.

That dumped plastic usually goes into a small tower printed next to your model, or into a bin. The tower is called a purge tower, sometimes a prime tower. It has no purpose beyond catching waste, and it gets rebuilt on every layer.

Now do the maths. Every single colour change flushes the nozzle. A model with a lot of colour changes can have hundreds or thousands of them. Owners regularly report that the waste pile weighs more than the finished model, sometimes several times more. That is not a defect, that is just how sharing one nozzle works. We went through this in detail when we compared the Bambu Lab AMS Lite, AMS, AMS 2 Pro and AMS HT.

There is a second way to do it. Instead of one nozzle sharing many filaments, give each filament its own nozzle, and let the printer put down one nozzle and pick up another. A machine that does that is called a toolchanger, and each nozzle assembly is called a tool.

Nothing gets flushed, because nothing ever mixes. Black stays in the black nozzle forever. That is the whole appeal, and it is what the INDX brings to the CORE One+.

Why toolchangers used to be expensive, and what Bondtech changed

Toolchangers are not new. Prusa's own XL has up to five tools. The catch has always been cost, because every tool is a complete print head. It needs a heater, a temperature sensor, wires running to it, and a way to connect and disconnect all of that reliably, thousands of times, without a loose contact ruining a twelve hour print. Multiply that by five or eight and the price gets silly.

Bondtech's answer was to take all the expensive parts out of the tools and leave them on the printer.

On an INDX machine there is one Smart Head that stays on the moving gantry. It holds the motor that pushes filament, the gears that grip it, and the electronics. The eight tools are dumb on purpose. Each is basically a nozzle in a metal shell.

Two tricks make that possible:

• Heating without a heater. The Smart Head carries an induction coil, the same technology as an induction cooktop in a kitchen. It creates a magnetic field that makes the metal nozzle itself heat up, from a small distance away. So the nozzle gets hot without ever being wired to anything. This is also why the nozzles have to be steel and not brass, which matters later.
• Reading temperature without touching. Instead of a sensor glued to the nozzle, the printer reads the nozzle's heat from a distance using infrared, the way a contactless forehead thermometer does.

Because the tools carry no electronics, they can be thin, light and cheap. That is the reason an eight tool system is affordable at all, and it is genuinely a new idea rather than a better version of an old one.

What happens to the wasted plastic

A toolchanger removes almost all the waste, but not quite all of it. When a nozzle sits idle, a little plastic can ooze out or shrink back, so the printer needs each nozzle to be flowing properly before it touches your model again.

Prusa's fix is neat and worth understanding, because it is the difference between "less waste" and "basically no waste". The nozzle presses into a V-shaped groove in a silicone wiper. The groove pushes back against the plastic coming out, which imitates the resistance of real printing, so the flow steadies immediately instead of needing a tower to steady itself against.

What gets left behind is a blob smaller than a grain of rice. It cools, falls off at the next tool change, and drops into a collector inside the machine. You empty that occasionally, and that is the entire waste story.

So the honest headline is not "eight colours". It is eight colours with no purge tower, on a printer you may already own.

How long a tool change takes

This is where people get suspicious, and rightly so. Heating a cold nozzle sounds slow.

The published figures are:

• Nozzle heat-up: 4 to 12 seconds, depending on how hot the material needs to be.
• Full tool change: around 12 seconds, measured the honest way, from the last line the old nozzle prints to the first line the new one prints. Bondtech quotes about 14 seconds for the complete sequence.

Is that fast? It depends on what you compare it to. A filament changer like an AMS takes longer than that and throws away plastic while doing it, so INDX wins easily. But other toolchangers with permanently heated tools, like the Snapmaker U1, swap in around four to five seconds because nothing needs heating up.

On a print with a thousand colour changes, seven extra seconds each adds up to about two hours. That is a real difference and you should know about it. It is also the trade you make for tools that cost a fraction as much, which is the same value question we worked through when we ranked 3D printer features from most to least worth paying for.

What comes in the kit

The INDX conversion kit is sold in two versions:

• 4-tool kit: one Smart Head, four tools, the mounting plate, tubing, spool holders, a filament runout sensor and the mounting hardware.
• 8-tool kit: the same Smart Head and the same mounting hardware, with eight tools and eight spool holders.

The important detail is that both kits contain the same expensive part, and the four tool version's mounting plate already has the four extra positions drilled into it. So starting with four and adding more later wastes nothing. If you are unsure, four is the sensible starting point.

The nozzles supplied are 0.4 mm, and you can buy other sizes separately: 0.25, 0.5, 0.6, 0.8 and 1.0 mm. Being able to keep different hole sizes loaded at once is arguably more useful than the colour trick. A 0.25 mm nozzle prints fine detail slowly. A 0.8 mm nozzle prints chunky parts fast. Normally you swap the nozzle by hand and re-calibrate. Here you just tell the slicer which tool to use for which part of the model.

Materials supported go up to 300 degrees C, which covers PLA, PETG, ASA, ABS, PC, nylon, TPU and the dissolvable support materials PVA and BVOH.

Does your printer have to be a CORE One+?

No, and this trips up a lot of buyers.

The kit fits the original CORE One and the CORE One+. The installation replaces the top lid, the spool holder and the filament path anyway, so most of what separates the two models gets swapped out during the build. Fit INDX to a plain CORE One and what you end up with is a CORE One+ with INDX on it.

For context, the "+" is a small update rather than a new machine. It adds a vent flap that opens and closes by itself depending on the material, an easier entry point for soft filaments like TPU, a twist-lock spool holder, and the firmware improvements collected over the CORE One's life. Prusa sells the CORE One to CORE One+ upgrade kit for pocket change, and the plastic parts are free to download and print yourself from Printables. An upgrade that costs the price of a coffee, or nothing if you print it, is a rare thing in this industry and worth saying out loud.

How much printing space you give up

Prusa is refreshingly specific here. With INDX fitted, the printable area shrinks from 250 x 220 x 270 mm to 248 x 205 x 270 mm. In plain terms, 2 mm off the width and 15 mm off the depth. Height is untouched.

Most people will never notice, but check it if you routinely print something that fills the bed.

The bigger cost is the space around the printer. Eight tools means eight spools of filament, mounted on the sides of the machine. The printer does not get bigger, but the table it needs does. Sort that out before the kit arrives, not after.

How long the installation takes

This is the part the launch videos skip, so read it twice.

INDX is not something you clip on. You have to take the printer's existing print head, the Nextruder, completely off. Then you fit the INDX carriage in its place, mount the rack that holds the tools, fit eight spool holders, add a calibration sensor at the front corner of the bed, and install a waste collector inside the machine.

Tom's Hardware spent most of a weekend on their eight tool kit. Estimates of the labour involved run to 7 to 12 hours.

Two things follow from that. First, you cannot currently buy a CORE One that arrives with INDX already fitted, so if the idea of dismantling an expensive printer makes you uneasy, wait. Second, the first print will not be push-and-go. Expect calibration runs, a firmware update and some reading. Prusa's INDX support section already has an article specifically about troubleshooting the first print, which tells you something.

The good news is that the fiddliest part is automatic. The printer works out the exact position of every nozzle by itself at the start of each print, by touching the bed to find height and scanning each nozzle over a sensor to find its left-right and front-back position. So you can swap tools around between prints without measuring anything by hand.

The nozzle problem you should know about before ordering

In July 2026 owners found a real issue, and it is worth understanding rather than panicking about.

Some filaments are abrasive. Anything with carbon fibre, glass fibre or glow-in-the-dark powder mixed into it is basically mild sandpaper flowing through a small hole. Ordinary nozzles wear out fast on those, so people buy hardened nozzles, where the metal is hard the whole way through.

INDX nozzles were advertised as hardened. Bondtech has since admitted that what actually shipped is ordinary steel that has been nitrocarburized, which is a surface treatment. The outside is tough, the inside is not. They had trouble producing the intended hardened version and substituted this late in development without telling anyone clearly. The Prusa forum thread about it is long and unhappy, both companies have corrected their wording, and replacements are being discussed.

What it means for you:

• If you print PLA, PETG, ASA, ABS, PC or dissolvable supports: this does not affect you at all. Those materials do not wear nozzles out.
• If you print carbon fibre or glass fibre filled filament: a treated surface wears through eventually, and then you are buying tools again. Either wait for a properly hardened nozzle or budget for replacements.

If you are not sure which filaments count as abrasive, our guide to picking the right 3D printing filament explains what each material is made of and how it behaves.

What it costs, and whether you can even buy one

Supply has been the story of this product. The first version, a limited run of 1,000 units sold by Bondtech, shipped first. The standard Prusa version opened for orders in April 2026 and sold out in a weekend. Prusa said the first of those kits would leave the factory at the end of July 2026, with the rest of that first batch out by the end of August. More batches are coming and you can register for a notification.

Pricing at the time of writing, July 2026, is roughly USD 749 for the four tool kit and USD 999 for eight, or about EUR 669 and EUR 899 including tax. Prices vary by country and move over time, so treat that as a guide and check the store for your own currency.

There is also a separate developer version sold directly by Bondtech, for people fitting the system to their own machines running Klipper or similar firmware. That one is sold as individual parts and expects you to know what you are doing.

What this actually costs in India

Here is the part that decides it for most readers here.

Prusa ships from the Czech Republic, so anything ordered from them lands in India as an import. Customs duty and GST are charged on top, and the courier collects that from you before delivering. Prusa explains the process in their customs and tax article.

The printer itself is easier, because Prusa has resellers in India. As of July 2026, Robu lists the CORE One+ self-assembly kit at Rs 1,61,300 including GST. The INDX conversion kit is not on Indian shelves yet, so that part has to be imported directly.

Put together, a CORE One+ plus an eight tool INDX kit plus duty puts you somewhere past Rs 2,50,000. That is before filament, before the eight spools you now have to keep dry, and before the weekend you spend building it. For comparison, the same reseller lists the fully assembled four tool Snapmaker U1 at Rs 1,30,000, which is why it was worth comparing against the Bambu Lab X2D in the first place.

Which leads to the question worth asking before you spend anything: do you want a toolchanger, or do you want one specific object printed in five colours with dissolvable supports? Those are completely different purchases. If it is the object you want, the machine is a detour. Send us the file and what comes back is the finished part, printed on a machine somebody else has already assembled, calibrated and kept running. That is what our custom printing service is for, and for anything that does not justify owning a toolchanger it is simply the cheaper answer.

Who should buy it, and who should not

Buy it if all of these are true: you already own a CORE One or CORE One+, you are comfortable taking it apart, and multi-material printing is real work for you rather than a novelty. That means dissolvable supports on complicated shapes, hard and flexible plastic combined in one part, colour used to make functional parts readable, or constantly switching nozzle sizes. For that person, INDX is the best answer on the market today, and it costs a kit instead of a new printer.

Skip it if any of these are true: this would be your first attempt at multi-material printing, you print carbon fibre parts and need them soon, the printer earns money every day and cannot be out of action for a weekend, or what you really want is four colours with no fuss for the least money. Those are different products, and pretending otherwise helps nobody.

The short version

Older colour systems melt one filament, then shove it out of the way with the next one, and you pay for that in wasted plastic on every single change. The INDX gives each material its own nozzle so nothing ever mixes, and it makes that affordable by taking the wires out of the nozzles and heating them from a distance instead.

That is a genuinely new idea in a category that had been recycling the same one for years. The nozzle mix-up is a bad look and the installation is long, but neither of those is the idea failing. Both are a first generation product behaving like a first generation product.

If you own the printer and the patience, this is the most interesting thing you can do with it in 2026. If you own neither, you are not missing out on anything that a finished part in your hand will not give you anyway.