This will be used to specifically analyze the advantages and disadvantages of AMS and printhead changing systems when handling multi-color/multi-material printing.
Let's see!
When discussing multicolor or multimaterial printing, one of the most frequently asked questions is: How do the Bambu Lab X1 and other Bambu Lab printers equipped with AMS compare to the Prusa XL printhead changing system?
Here, I would like to provide you with all the details of these two multicolor printing solutions and help you decide which machine and process is right for you.
In today's test, I chose the Bambu Lab X1 equipped with AMS and the Prusa XL with a 5-printhead module—these are the printers I've used the most over the past year, giving me ample practical experience.
While some of these figures and conclusions may be specific to these models, the general conclusions also apply to other machines using similar methods.
Multiplexing and nozzle replacement
Bambu Labs uses multiplexing in its configuration, and Creality, Anycubic, and Prusa's MMUs also use the same method.
As for nozzle replacement systems, apart from the Prusa XL, there are almost no other readily available solutions on the market.
Let’s first analyze the main technical differences between Bambu Lab’s AMS multicolor system and Prusa XL’s tool replacement method.
Most current multi-material or multi-color settings use a process called multiplexing, which means that multiple wire inputs are fed into a single nozzle.
For example, using the Bambu Lab X1, the AMS has multi-axis cables, and each cable can be fed into a hot end of the printing chamber.
This is a relatively simple and inexpensive system because you only need an extruder/hot end assembly.
However, when switching lines, many machines cut off the loaded material at the hot end to avoid pulling the soft plastic sheet back into the feeder—which can easily cause blockages or clogging.
The downside is that any remaining wires in the hot end must be removed before the new color can be printed cleanly.
This may require a lot of clearing, especially when you switch to a lighter color.
Bambu Lab is known for its "cleaning up feces" and it does a great job of showing color changes, but even that is often not enough.
Therefore, these machines usually also print a wiping tower next to the actual parts.
On the other hand, the nozzle replacement system uses a separate hot end for each wire.
When the tool is not in use, it rests on the base, and the printer's motion system picks up the tool that is needed at that time.
The biggest advantage is that you don't need to clear between color changes - there are no material changes, so there's no mixing within a single hot end - which greatly reduces wire waste.
However, this adds complexity: you not only need multiple complete extruders and hot ends, as well as the nozzle replacement system itself, but all of these require more space, which makes the machine larger.
Each printhead must also be precisely aligned in the X and Y directions and along its length so that the parts it prints are perfectly aligned with each other.
Although the nozzle replacement pickup mechanism is very precise and repeatable, the tolerances of each component mean that you still have to measure the offset of each nozzle.
There are different ways to do this. Prusa uses its weighing sensors to detect pins mounted on the bed, directly measuring the position and height of each tool.
With multiplexing like Bambu Lab , you can avoid those extra alignment steps because all the filaments come from the same nozzle, ensuring that the printed objects are naturally and perfectly aligned.
Now that we've covered the fundamental differences between multiplexing and printhead replacement in multi-color or multi-material 3D printing, let's delve into how they actually affect print time, material waste, print quality, and material compatibility. The goal is to help you understand which method is best suited for your needs.
Let's start with material waste, because that's one of the biggest points of discussion.
Material waste comparison
Bambu Lab printers are known for producing what's called "cleaning up feces" every time the cable is switched.
Each color change produces a small piece of plastic, and the total number of color changes in a print largely depends on how you design and position the model.
To illustrate this, I printed out two different examples, both using four colors. The first is a cylinder with vertical stripes running from top to bottom.
The second is a cylinder divided horizontally into four colored segments. In the striped version, each layer requires three color swaps, for a total of 40 layers and approximately 120 variations.
Each change will generate a "feces" item and some additional cleaning materials on the tower.
The final part itself weighs only 8.3 grams, but it generates 29.6 grams of "waste," and another 7.7 grams are generated on the cleaning tower—so for an 8-gram print, 37 grams of waste are produced. This may sound a bit extreme, but that's how the process works when the colors are constantly changing.
Some people suggest "rinsing" the cable into the filler to reduce waste.
In this case, it only saved me about 1.5 grams, or 5%. For larger prints, rinsing may be more helpful, but it can also cause unwanted colors to show through the walls, ruining the final appearance.
Besides the number of changes, two other factors affect the final amount of material cleared. When early multiplexed printers first appeared, they cleared the same amount of wire each time a color was changed.
However, it takes much more cable to go from black to white than from white to black.
Modern slicers typically have a "smart removal amount" setting that automatically adjusts the removal amount based on color changes.
If you turn this setting on in the slicer, you will see that transitions from dark to light get more cleansing, while transitions from light to dark use less cleansing.
Next is the cleaning multiplier. This is a simple scaling factor used to calculate the cleaning volume.
Lowering it means you'll waste less material, but it also increases the likelihood of color pollution.
I tend to set it around 0.5, which usually keeps the colors clean. If you're always printing the same few colors, you can perform a calibration test for precise adjustments and save even more.
However, most people would rather be cautious and clean more than risk soiling the printout.
Finally, there are some advanced techniques that involve how and when to retract the wires to further reduce clearance, but this can affect reliability.
Therefore, the preset profiles on Bambu Lab printers usually result in slightly higher waste, but they are also more reliable for various cables.
The amount of cleaning will vary depending on the machine you use, but you must always clean to remove the old filament from a single nozzle that pushes all the material through.
Let's continue discussing the printhead replacement system. Each color has its own hot end, so there's no color contamination and therefore no need for cleaning, right?
By default, the Prusa XL's slice profile includes a wiping tower.
When you switch to the new tool head, the XL removes a small amount of material from the part before it begins printing the actual part. This removal is much smaller than the "removal poop" or tower produced by a typical Bambu Lab print.
For example, through our worst-case test (a cylinder that requires tool changes three times per layer), the finished print weighed only 9.1 grams, while the wipe tower gained about 4.6 grams.
This is only 12% of the waste we see on Bambu machines. But there is still some waste.
Why? Well, even when the tool is parked, it will remain heated.
Lowering the temperature reduces leakage and covers the nozzle orifice, but the plastic in the molten zone will slowly degrade due to being in a hot chamber.
If you've ever preheated the hot end of a cable to replace it, then forgotten about it for a few minutes before reloading the new material, then you probably know what I'm talking about.
The remaining wire will become soft and will degrade when heated.
If you pick up the tool and start printing immediately (without any cleaning), you will get a lot of stringiness and inconsistent extrusion.
I conducted this precise test using a warthog model and found the differences to be highly significant.
The version printed using the wipe tower is very clean, while the version without the wipe tower is covered with streaks and has holes, which is caused by the degraded filaments not being printed correctly.
Therefore, the main purpose of a wiping tower is to remove "bad" plastic so that you can start printing again with reliable materials.
To some extent, Prusa's wiping tower is a conservative approach—designed to work with a wide variety of cables.
However, with the right precautions, it's possible to skip the wiping tower and still get good results. In my experience, you only need to dry the wire.
The lower the humidity, the less leakage and hydrolysis occur at high temperatures, thus allowing the plastic to maintain its properties for a longer period of time under high-temperature conditions.
I put the PLA spool in the wire dryer overnight, and the next day, I printed the exact same g code on the XL—only this time I was using dried wire.
The results were fantastic. The warthog model looked just as clean as the model with the wipe tower, and I saved 26.5 grams of filament and reduced the printing time from 9 hours by 50 minutes.
This leads to our next important topic: printing time.
Printing time
Yes, changing tools takes time, and printing can involve hundreds or even thousands of tools.
On the Prusa XL, depending on the distance between the tools, changing a tool takes about 7-9 seconds, plus 5 seconds to clean the wiping tower.
Each color swap takes approximately 12-14 seconds in total.
Meanwhile, on the Bambu Lab X1, the color change may take 1 to 3 minutes, depending on the amount that needs to be removed.
The reason is as follows: First, clean the nozzle, then cut the wire and retract it all the way to the AMS, and finally feed in the new wire.
The last step alone takes another 20 seconds to restore the print job.
To put it another way: if you have 500 color changes, and each change takes an average of 100 seconds, that means that just switching colors and generating waste would take nearly 14 hours.
This is absolutely insane, and it explains why color printing on multiplexed systems takes so long.
On the XL, each change takes approximately 12 seconds, so you can complete the same job of changing tools in just 1.5 hours.
Now, an interesting fact is that the time required to change the cable remains constant, regardless of the size of the printout or the number of parts printed.
If we look at the test section on the Bambu X1, printing just one sheet takes 213 minutes. If we print five sheets at once, the total time increases to 266 minutes, meaning each sheet takes only 53 minutes, which translates to a 75% reduction in printing time per sheet.
If you fill the entire plate, the time required for each part can be reduced to 27 minutes, resulting in an overall reduction of nearly 90%. This is because while the color changes remain constant, you are spreading them across more parts.
On printhead changers like the Prusa XL, the benefits of printing multiple parts are not so significant.
Printing one sheet takes 40 minutes, and printing five sheets takes 23 minutes each—otherwise, not much time is saved.
Because the XL changes tools very quickly, it doesn't waste much time on useless color swapping.
This means that even single-part jobs can be completed fairly quickly, and the difference between monochrome and multicolor printing is relatively small.
Print quality
Before we move on to multi-material printing, let’s quickly take a look at the print quality of these machines.
Early reviews of the Prusa XL frequently mentioned layer shifting, stringing, and many were dissatisfied with its initial performance.
Fortunately, things have changed a lot in the past year. When the XL first shipped, Prusa equipped it with a 0.6 mm nozzle because it believed that larger machines should have larger nozzles.
Ultimately, they switched back to the 0.4 mm nozzle, which is basically the industry standard.
My XL arrived about a year ago, with the 0.4 mm nozzle already installed, but I'm still having some issues. Some of these might be due to quality control problems: my tool head is faulty, and the belt is very loose when I take it out of the box.
After fixing the problem, I still tried to print a whole set of colorful Catan on the XL as a birthday present for my brother, but even with the wipe tower, the little "sheep" model didn't look very good.
Therefore, I switched back to my Bambu X1 to complete this task.
However, Prusa updated its firmware and improved the slicer profiles over the past year. So I decided to reprint my favorite Catan tiles to see if anything had really changed—and the difference was impressive.
The new print has a lot of detail and very few defects.
I even run without using a wiping tower and with fresh, dry wire.
They still look amazing! The larger models look impressive too – hundreds of tool variations and perfectly aligned layers.
The only problem I encountered was that some nozzles were misaligned when I forgot to clean them.
Once I cleaned out the dirt and recalibrated, everything was back to normal.
Therefore, it appears they have solved the problems for most early adopters.
In my opinion, the XL now offers the best multi-material printing quality on the market, comparable to, and sometimes even better than, the quality I get from Bambu Lab machines if you want to compare.
So far, we have mainly talked about multicolor printing—using different colors of the same material.
However, one of the biggest selling points of printhead changers like the Prusa XL is not just faster color changes, but also multi-material printing capabilities.
What's the difference here?
It's easy to print multiple colors using the same type of cable (such as PLA) because everything operates at the same temperature and has similar material properties.
This is very useful for decorative or aesthetic projects. However, in multi-material printing, you might combine a PLA body with flexible TPU hinges or washers, or use other support materials that can be peeled off more cleanly. AMS-based or multiplexed printers will start to struggle with this, especially when printing on flexible materials.
Sending soft, fluffy filaments through long tubes can cause blockages, and although Bambu Lab recently released their own AMS-compatible TPU, it is quite rigid compared to typical flexible materials.
There's an even bigger problem. Some materials just don't work well together. For example, PLA and PETG. If you've ever converted from PETG to PLA and wondered why the first layer peels off, you've seen this problem firsthand. They just don't bond or fuse.
Therefore, on multiplex printers, if you don't remove all PETG residue from the printhead, the adhesion and strength of your PLA layer will be severely affected – right where the remaining PETG contaminates the print.
This is where the nozzle replacement system truly comes into play.
You never exchange materials through the same hot end, so there is no residual contamination and no need for large-scale cleanup.
This means you can use pure PETG support for PLA printing, which peels off easily and produces an ultra-clean bottom.
The challenge here is more about bed temperature, because each material may prefer different building surface types and temperatures.
Getting the two materials to bond properly can be tricky, and frankly, that's the biggest challenge.
However, multi-material printing remains a strength of printhead replacement systems .
In the past, I've printed rollers with integrated IGUS DryLin bearings, hooks with foam TPU cushioning, and articulated PLA hands using TPU as joints, but these things are simply not practical in an AMS setup.
This is not to say that the nozzle replacement system is without problems. For example, I tried using only the PETG support interface on PLA parts, but encountered a problem where the PETG could not adhere to the PLA.
Additionally, if you set the following printing temperature for PLA, the PETG on the bed may peel off. Therefore, you will still need to adjust your process for each material combination.
But if you do it right, you can create some impressive prints.
Please remember that the standard form of the Prusa XL is an open-type 3D printer. It is ideal for PLA, PETG, TPU, and other materials that do not require elevated printing chamber temperatures.
Prusa also offers their PCBLend, which I really like for printing technical parts, and it's designed to print without a housing, but even so, the higher print chamber temperature makes it more advantageous.
They do sell cases for the XL, but if you’re strictly printing ABS, ASA, nylon, or polycarbonate, a small, enclosed printer like the Bambu Lab X1 or P1S might give you a more robust part out of the box—though only in single-material models.
Cost becomes a major factor here.
The XL case alone costs $649, almost as expensive as the Bambu Lab P1S with AMS.
Therefore, deciding which printer to buy depends not only on its features or how much waste each printer produces—it may also depend on your budget.
in conclusion
From my personal experience, if you compare the fully-featured Prusa XL with the Bambu Lab X1 Carbon side by side, you'll find that there are very few things the Bambu can do that the XL can't.
Bambu's biggest advantage is its slightly faster speed and the ability to connect up to four AMS units, thus providing 16 colors.
Furthermore, the X1 is pre-closed, which makes printing with high-temperature materials much easier.
In addition, the print quality is excellent, and large printing plates are very convenient. Its tile heating system, while complex, remains highly efficient even for smaller prints.
In my opinion, the Prusa XL is a business-class printer.
The single-nozzle version starts at $2,000, with upgrades available later.
The assembled five-nozzle version costs approximately $4,000, and if you add the housing and some drying boxes, the total price can reach $5,000.
Therefore, you either need substantial financial resources or a very specific reason to own it.
Perhaps you are using PLA, PETG, or TPU to perform multi-material work on a single component.
Or if you're a professional where time is money, the XL's printhead replacement feature can save you countless hours when printing multi-tool parts.
Finally, Prusas machines are manufactured within the EU; they have excellent customer support and explicitly emphasize that their machines can ensure the security of your data, which could be very valuable to you.
They won't force you to use the cloud, but if you value privacy or run a business, this could be a big deal.
Personally, I enjoy using the XL. It's a machine that runs out of the box with minimal tweaking, thanks to PrusaSlicer's robust ecosystem, and delivers impressive results after numerous firmware and configuration file updates.
Additionally, if you already own a Prusa printer, I've heard that the MMU3 is finally working quite well, even capable of printing five colors simultaneously (though I haven't tried it myself yet).
In short, we now have a really wide range of options, which is fantastic. I hope this gives you a clearer understanding of the comparisons between the different systems and which systems might be suitable for your project.
A printhead replacement system is undoubtedly the most effective method, but it adds complexity and cost—hence the higher price of the XL and the scarcity of competitors.
If you can take advantage of its true multi-material capabilities or save time, then this is an excellent choice.
But if not, then a multiplexing-based solution might be what you need.
Of course, AMS printers are slower and waste more material, but how many people actually print enough to justify the extra cost of XL?
If you're really worried about waste, multicolor 3D printing might not be the best option.
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