He provides a detailed analysis of the pros and cons of using AMS versus a toolchanger for multi-color/multi-material printing.
Let’s take a look together!
One of the most common questions regarding multi-color and multi-material printing is how the Bambu Lab X1 and other Bambu Lab printers equipped with AMS compare to the Prusa XL with its toolchanger.
Here, we will introduce these two multi-color printing methods in detail to help you determine which machine and process is right for you.
For this test, we chose the Bambu Lab X1 with AMS and the 5-head Prusa XL. Since these are the printers we have used the most over the past year, we have plenty of practical, real-world experience with them.
While some of the figures and conclusions may be specific to these models, the general findings apply to other machines using similar methods.
"Multiplexing" vs. "Tool Changing"
The Bambu Lab configuration uses multiplexing. MMU systems from Creality, Anycubic, and Prusa work in the same way.
On the other hand, there are almost no commercially available, ready-to-use alternatives to the Prusa XL for the tool-changing method.
Let's start by looking at the primary technical differences between multi-color systems like the Bambu Lab AMS and the Prusa XL's tool-changing system.
Currently, many multi-material and multi-color configurations use a method called multiplexing, which feeds multiple filaments into a single nozzle.
For example, with the Bambu Lab X1, you can feed filaments from multiple spools in the AMS into one hotend inside the build chamber.
Because it only requires a single extruder and hotend combination, it is a relatively simple and inexpensive system.
However, when switching filaments, most machines cut the material at the hotend because if the softened resin is pulled back into the feeder, it is prone to clogging and jamming.
The drawback is that the filament remaining in the hotend must be purged before you can print cleanly with a new color.
Especially when switching to lighter colors, a large amount of purging may be required.
Bambu Lab is known for its "poop-like" purge waste. While it makes color changes easy to see, it is often not enough on its own.
For this reason, these machines typically also print a purge tower next to the model.
Conversely, the tool-changing method uses a separate hotend for each filament.
Tools not in use are left in a dock, and the printer's movement mechanism picks up the one it needs.
The biggest advantage is that there is no need to purge every time you change colors. Since materials are not swapped within the same hotend, there is no mixing, significantly reducing filament waste.
However, the structure is more complex. It requires multiple extruders and hotends, plus the tool-changing mechanism itself, and requires more space, making the machine larger.
Each head must be precisely aligned in the X and Y directions, as well as in length, to ensure that the parts they print match up perfectly.
Even if the tool-changing pickup mechanism is highly accurate and repeatable, part-to-part tolerances mean you must measure the offset of each head.
There are several ways to measure this, but Prusa uses a load cell to detect pins attached to the bed, measuring the position and height of each tool directly.
In contrast, with multiplexing systems like Bambu Lab's, since all filaments come out of the same nozzle, you can skip the additional alignment steps, and the positions of each section naturally match up.
We have explained the fundamental differences between the two methods for multi-color/multi-material 3D printing. Next, let's look at how they actually affect print time, material waste, print quality, and material compatibility to decide which method is best for your application.
First, we will look at one of the biggest points of contention: material waste.
Comparing Material Waste
Bambu Lab printers are known for producing "poop-like" purge waste every time they switch filaments.
Every time you switch colors, a small lump of resin is produced. The number of color changes during a print varies greatly depending on the design and arrangement of the model.
To demonstrate this, we printed two types of samples, both using 4 colors. The first is a cylinder with vertical stripes from top to bottom.
The second is a cylinder divided into 4 horizontal color segments. The striped model requires 3 color changes per layer; with 40 layers, that's about 120 changes.
In addition to producing purge waste for every switch, extra material is also used for the tower.
The finished part itself was only 8.3g, but 29.6g of waste was produced, along with 7.7g of material used for the purge tower. In other words, for an 8g model, there was about 37g of waste. It may sound extreme, but this is the reality of this method when switching colors frequently.
Some people recommend purging filament into the infill to reduce waste.
In this case, we saved about 1.5g, or only 5%. This might be more effective for large prints, but the unwanted colors could show through the walls and compromise the appearance of the finished product.
Besides the number of switches, there are two factors that affect the final purge amount. Early multiplexing printers used to purge the same amount of filament for every color change.
However, switching from black to white requires significantly more filament than switching from white to black.
Modern slicers often include a "smart purge" setting that automatically adjusts the purge amount based on color transitions.
Looking at that setting in the slicer, you can see that the purge volume is higher when switching from dark to light colors and lower when switching from light to dark.
Another is the purge volume multiplier, a simple coefficient multiplied by the calculated purge amount.
Lowering the value reduces material waste, but increases the likelihood of color bleeding.
I often set it around 0.5, which is usually enough to keep the colors clean. If you always use the same few colors, you can fine-tune it with calibration tests to save even more.
However, many people would rather purge a bit more than risk a discolored model.
Finally, there are advanced techniques to further reduce purging by optimizing how and when filament is pulled back, but this impacts reliability.
Therefore, while the default Bambu Lab profiles produce a bit more waste, they are highly reliable across a wide range of filaments.
Purge amounts vary by machine, but purging is always necessary to remove old filament from a single nozzle that handles all materials.
So, how about the tool-changing method? Since each color has its own dedicated hotend and colors don't mix, is purging unnecessary?
The default Prusa XL slice profile includes a purge tower.
When switching to a new tool head, the XL purges a small amount of material before printing the actual part. This amount is significantly less than the purge waste and tower produced in a typical Bambu Lab print.
For example, in our most rigorous test—a cylinder that switches tools 3 times per layer—the finished part was 9.1g, and the purge tower was about 4.6g.
This is just 12% of the waste produced by the Bambu machine. Still, there is some waste.
Why? Because the tools remain heated while on standby.
Even if you lower the temperature and cover the nozzle opening to reduce oozing, the resin in the melt zone stays in the hot interior and gradually degrades.
If you've ever preheated a hotend to change filament and then forgot about it for a few minutes before inserting new material, you might know what I mean.
The remaining filament softens and degrades due to the heat.
If you pick up that tool and start printing immediately without purging, you will see a large amount of stringing and uneven extrusion.
I actually tested this with a warthog model and confirmed a very large difference.
The print with the purge tower was clean, but the one without was covered in stringing, and holes were missing because the degraded material was not extruded properly.
Therefore, the main purpose of the purge tower is to remove degraded resin so that printing can resume with stable material.
In a sense, the Prusa purge tower is a conservative method to support various filaments.
However, if you take proper countermeasures, you can get good results even without the tower. In my experience, all you need to do is keep the filament dry.
The lower the moisture content, the less oozing and hydrolysis occurs at high temperatures, allowing the resin to maintain its performance longer in high-heat environments.
I put a PLA spool in a filament dryer overnight, and the next day, printed the exact same G-code on the XL. The only difference was the dry filament.
The results were fantastic. The warthog model was as clean as the one with the purge tower, saving 26.5g of filament and reducing a 9-hour print by 50 minutes.
This leads us to the next important topic: print time.
Print Time
Tool changing takes time each time, and a single print can involve hundreds or thousands of changes.
On the Prusa XL, depending on the distance between tools, one change takes about 7–9 seconds, plus 5 seconds to purge into the tower.
That's a total of about 12–14 seconds per color change.
On the other hand, with the Bambu Lab X1, depending on the required purge amount, a color change can take 1–3 minutes.
This is because the nozzle must first be cleaned, the filament cut and retracted to the AMS, and finally the new filament fed in.
The final step alone adds another 20 seconds before printing resumes.
To put it another way, if there are 500 color changes and each takes an average of 100 seconds, you spend about 14 hours just on color switching and waste discharge.
That is an incredible amount of time. You can see why multi-color printing takes so long with the multiplexing method.
With the XL, since one change is about 12 seconds, the same tool change task takes only about 1.5 hours.
Interestingly, the time it takes to change filament does not change regardless of the size or number of parts.
A single test part on the Bambu X1 takes 213 minutes. Printing 5 together takes 266 minutes, which is 53 minutes per unit—a 75% time reduction.
If you fill the entire plate, it can be reduced to 27 minutes per unit, an overall reduction of about 90%. This is because even if the number of color changes is the same, that time can be spread across more parts.
With a toolchanger like the Prusa XL, the effect of batching multiple items is not as significant.
One item takes 40 minutes; 5 items take 23 minutes each, with little time savings beyond that.
This is because the XL's tool changes are so fast that it doesn't spend much extra time on color changes.
Therefore, even printing just one item is relatively fast, and the time difference between single-color and multi-color prints is smaller.
Print Quality
Before we move on to multi-material printing, let's briefly look at the print quality of these machines.
Early Prusa XL reviews often pointed out layer shifts and stringing, and many were unhappy with initial performance.
Fortunately, things have changed significantly over the past year. When the XL started shipping, Prusa believed large machines needed large nozzles and adopted 0.6mm nozzles.
They eventually reverted to 0.4mm nozzles, which are the de facto industry standard.
My XL arrived about a year ago with a 0.4mm nozzle installed, but there were still some issues. Some seemed to be due to quality control; a tool head failed, and the belts were extremely loose out of the box.
After fixing the issues, I tried printing a whole set of colorful Catan tiles on the XL as a birthday gift for my brother, but even with a purge tower, the small "sheep" models didn't turn out well.
So, I moved that job back to the Bambu X1 to finish it.
However, over this past year, Prusa improved the firmware and slicer profiles. When I printed my favorite Catan tiles again, the difference was astounding.
The new prints had well-reproduced details and almost no defects.
I used fresh, dry filament and tried it even without a purge tower.
The results were still wonderful! Large models, after hundreds of tool changes, had perfectly aligned layers with impressive results.
The only problem was when I forgot to clean the nozzles, and some became misaligned.
After cleaning and recalibrating, everything returned to normal.
Many of the issues encountered by early users appear to have been resolved.
In my opinion, the XL now offers some of the highest multi-material print quality on the market. In comparison, the quality is on par with, and sometimes exceeds, what you get from Bambu Lab machines.
So far, we have mainly talked about multi-color printing, using different colors of the same material.
However, the great appeal of a toolchanger like the Prusa XL lies not only in fast color switching, but also in its multi-material printing capabilities.
How do they differ?
Printing multiple colors with filaments of the same type, such as PLA, is relatively easy because the temperatures are the same and the material properties are similar.
This is useful for decorative or aesthetics-focused projects. On the other hand, in multi-material printing, you might combine a PLA body with flexible TPU hinges or gaskets, or use a separate support material that is easier to remove. Multiplexing printers like the AMS find this difficult, especially when using flexible materials.
Passing soft filament through long tubes can cause clogs. Bambu Lab recently launched AMS-compatible TPU, but it is much stiffer than standard flexible materials.
There is also a bigger problem: incompatible material combinations like PLA and PETG. If you've ever had a first layer peel off when switching from PETG to PLA, you've seen this issue. They do not adhere or fuse to each other.
Therefore, if you don't completely remove the PETG from the head in a multiplexing printer, the residual PETG will mix, significantly compromising the layer adhesion and strength of the PLA.
This is where the tool-changing method shines.
Because you aren't switching materials in the same hotend, there is no contamination from residual material, and no need for massive purging.
This means you can use pure PETG as support for a PLA model, making it easy to remove and resulting in an exceptionally clean surface.
The challenge here is the bed temperature. This is because suitable build surfaces and temperatures vary by material.
Getting two materials to bond properly is difficult; honestly, this is the biggest challenge.
Still, multi-material printing is a field where the tool-changing method excels.
I have previously printed rollers with IGUS DryLin bearings, hooks with foam TPU cushioning pads, and articulated PLA hands with TPU joints. These are not practical in an AMS configuration.
However, the tool-changing method is not without its problems. For example, when trying to use PETG only on the support contact surfaces of a PLA part, I encountered the issue where PETG wouldn't stick to the PLA.
Also, printing at PLA temperatures can cause PETG on the bed to peel. You have to adjust the process for each material combination.
Even so, when handled correctly, you can create impressive prints.
Remember that the Prusa XL is not an enclosed machine by default. It is suitable for materials like PLA, PETG, and TPU that do not require an elevated chamber temperature.
Prusa also offers PCBlend, which I like to use for printing functional parts. It is designed to be printed without an enclosure, but there is still a benefit to higher chamber temperatures.
An XL enclosure is available for sale, but if you primarily use ABS, ASA, nylon, or polycarbonate, a small enclosed printer like the Bambu Lab X1 or P1S might be able to create stronger parts in their standard configuration—though only in single-material mode.
Cost is a major factor here.
The XL enclosure alone costs $649 USD, which is close to the price of a Bambu Lab P1S with AMS.
Deciding which machine to buy isn't just about features or the amount of purge waste, but also about your budget.
Conclusion
In my experience, when you put a fully featured Prusa XL side-by-side with a Bambu Lab X1 Carbon, there is almost nothing the Bambu can do that the XL can't.
The biggest advantages of the Bambu are its slightly faster speed and the ability to connect up to four AMS units for 16-color printing.
The X1 is also enclosed by default, making printing with high-temperature materials easier.
Additionally, print quality is very high, and the large build plate is convenient. The tiled heating system is complex, but it maintains efficiency even for small prints.
To me, the Prusa XL is a professional machine.
The single-head version starts at $2,000 USD, and you can add tools later.
The pre-assembled 5-head version is about $4,000 USD, and adding an enclosure and dry box brings the total to $5,000 USD.
Therefore, you need a sufficient budget or a clear reason for implementation.
For example, using PLA, PETG, and TPU to combine multiple materials in one part.
Or, if you are a professional for whom time is money, the tool-changing function of the XL can significantly reduce print time for parts using multiple tools.
Finally, Prusa equipment is manufactured in the EU. Excellent support and a clear emphasis on data security may also be of great value.
The fact that it doesn't force you to use the cloud is likely important for those who value privacy and for businesses.
Personally, I like using the XL. It started working with almost no adjustment, has a powerful ecosystem thanks to PrusaSlicer, and after numerous firmware and profile updates, it now delivers fantastic results.
Also, if you already have a Prusa printer, I've heard the MMU3 is finally easy to use and capable of 5-color printing. However, I haven't tried it myself.
It's great that there are such a wide variety of choices now. I hope this comparison helps you understand the differences between the systems and what is suitable for your projects.
The tool-changing method is definitely the most efficient, but it increases complexity and cost. That is why the XL is expensive and has few competitors.
If you can leverage serious multi-material functionality or time savings, it is an excellent choice.
Otherwise, a multiplexing method might be enough.
Indeed, printers using AMS take time and increase material waste. But honestly, how many people print enough to justify the additional cost of an XL?
If you are truly worried about material waste, multi-color 3D printing itself might not be the best choice for you.
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