This article is part of the Prusa XL Technical Series on INVESTEGATE.de
All guides assume that the Prusa XL Fundamentals are correct.
If not, start here:
Prusa XL Basics – Technical Fundamentals
The Prusa XL is a powerful and well-engineered printer, but it is not perfect out of the box.
Some weaknesses only become apparent after extended use, multi-tool printing, or when working with demanding materials like PETG or TPU.
This article focuses exclusively on practical, tested mods that solve real problems:
first-layer reliability, filament handling, cooling consistency, mechanical stability, and thermal behavior.
No cosmetic upgrades.
No untested ideas.
Only modifications that provide measurable improvements in daily operation.
Each mod is clearly classified as Must-have, Recommended, or Optional, with notes on installation effort, material choice, and use cases such as enclosed printing or multi-material setups.
Brush Mods
ScrubbyXL (MBL & during printing)
Recommendation: ✅ Must-have
Problem
During MBL and especially long prints, filament can slowly build up on the nozzle tip (PETG is a common culprit), which can lead to poor probing/first-layer inconsistency and eventually print defects or failures.
Solution
ScrubbyXL integrates simple G-code routines into your slicer: a Start G-code wipe before MBL so the nozzle probes the bed cleanly, plus optional in-print wipes triggered every X layers (user-defined) to keep the tip clean during long jobs.
Observed benefits
- no manual nozzle cleaning
- cleaner, more consistent first layer (clean nozzle during MBL)
- reduced nozzle-tip buildup over time; fewer long-print failures
- less manual “pause and clean” maintenance mid-print
- especially effective with PETG
Verdict
A practical reliability mod: minimal workflow changes, but a big payoff on long prints and “messy” materials like PETG.
ScrubbyXL Automatic Slicone Wipe Mod (MBL & during printing) (Recommended)
Bedleveling Brush (MBL)
Recommendation: ✅ Must-have
Problem
Nozzle contamination is one of the most common causes of inconsistent first layers.
The stock cleaning routine often fails to remove PETG residue or burnt material.
Solution
The brush mechanically cleans the nozzle before mesh bed leveling (MBL) removing residue reliably.
Observed benefits
- stable and repeatable first layer
- no manual nozzle cleaning
- especially effective with PETG
Verdict
A simple, robust solution to a real problem.
This should be standard equipment on every Prusa XL.
Download the MBL Brass Brush Mod on Printables (MBL only)
Bonus: I Reworked the G-code to improve the cleaning result (more reliable wipe behavior):
Start G-Code Cleaning routine
; move to the nozzle cleanup area
; Surfalex2000 Nozzle Brush Mount on Printables
; https://www.printables.com/model/644817-prusa-xl-series-front-nozzle-srcubber-for-use-with
G1 E-10 F2400 ; more retraction to compensate oozing before nozzle cleanup
; Start surfalex2000 nozzle brush cycle
; --- Start nozzle brush cycle (speed ramp) ---
G1 X160 Y-5 Z5 F8000
G1 X160 Y-5 Z1 F8000
; --- Zyklus 1 (langsam) ---
G1 X200 Y-5 F8000
G1 X200 Y-4
G1 X160 Y-4
G1 X160 Y-6
G1 X200 Y-6
G1 X200 Y-5
G1 X160 Y-5
; --- Zyklus 2 (mittel) ---
G1 X200 Y-5 F14000
G1 X200 Y-4
G1 X160 Y-4
G1 X160 Y-6
G1 X200 Y-6
G1 X200 Y-5
G1 X160 Y-5
; --- Zyklus 3 (schnell) ---
G1 X200 Y-5 F16000
G1 X200 Y-4
G1 X160 Y-4
G1 X160 Y-6
G1 X200 Y-6
G1 X200 Y-5
G1 X160 Y-5
; --- Zyklus 4 (schnell) ---
G1 X200 Y-5 F20000
G1 X200 Y-4
G1 X160 Y-4
G1 X160 Y-6
G1 X200 Y-6
G1 X200 Y-5
G1 X160 Y-5
G1 X160 Y-5 Z5 F20000 ; nozzle brush cycle
; End surfalex2000 nozzle brush cycle
I’ve combined both brush mods. This way, the area before MBL is first cleaned with the brass brush mode and then again with the silicone mod. If you’d like to do this too, I’ve perfected a G-code for it.
Toolchanger Brush
Recommendation: ✅ Must-have for multi-tool setups
Problem
During tool changes, nozzle tips often accumulate residue, leading to color contamination and visible artifacts.
Solution
The nozzle is cleaned automatically during every tool change.
Important clarification
This does not compensate for wet filament.
Proper filament drying is still mandatory.
Verdict
Essential for clean multi-material prints.
If you use multiple toolheads, this is not optional.
Whether with silicone or brass brushes.
Download the Toolchanger Brush Mod on Printables
Magnetic Filament Sensor
Recommendation: ✅ Must-have for PETG & TPU
Problem
The stock filament path introduces unnecessary friction.
TPU feeding can be unreliable, and PETG often produces audible friction (“squeaking”).
Solution
The magnetic sensor reduces resistance in the filament path significantly.
Observed benefits
- reliable TPU feeding
- reduced filament friction
- smoother extrusion with PETG
Verdict
A clear functional improvement with no downsides.
Strongly recommended if you print anything other than PLA.
Download the Side Filament Sensor Magnetic Mod on Printables
Download the Tool Filament Sensor Mod on Printables
Nextruder Main Plate
Recommendation: ✅ Must-have for regular FLEX printing.
Problem
The open filament entry slot allows flexible filament and debris to enter the extruder housing, potentially causing feeding issues.
The flexible filament can then become entangled there.
Solution
This modded main plate closes this opening.
Critical installation notes
- The planetary gear must be opened
- A 3D-printed assembly tool is mandatory to avoid damage
- Read the official Prusa instructions before starting
The required tool can be found on Printables under
“Prusa XL printable parts”
Verdict
Worth installing if you already disassemble the extruder or regularly print flexible materials.
Download the Nextruder Main Plate Mod on Printables
or a newer project: Download the Nextruder Main Plate Mod for Bogie Idler on Printables
Nozzle Fan Duct
Recommendation: ✅ Recommended
Problem
The stock nozzle fan duct provides uneven airflow and suboptimal cooling distribution around the nozzle.
Solution
An improved duct delivers more consistent and directed airflow.
Material
- Print it in PA-CF or PC-CF (Or PA12 SLS)
Verdict
A sensible upgrade that improves cooling consistency and reduces print variability.
Download the Fan Duct 1 on Printables (Recommended)
Download the Fan Duct 2 on Printables
Toothed Idler Pulleys
You may have noticed that there are two idler pulleys in the X-carriage, where the toothed side of the belt is guided over smooth idler pulleys. Why Prusa doesn’t use toothed idler pulleys for this is a mystery to many. This can cause the belt to deform. Therefore, it is recommended to use toothed idler pulleys.
Recommendation: ✅ Recommended
Problem
In several locations, the toothed side of the belt runs over smooth idler pulleys.
This can lead to belt deformation and accelerated wear.
Solution
Replacing them with toothed idler pulleys ensures proper belt engagement.
Verdict
A technically correct upgrade that improves belt longevity.
This should have been part of the original design.
Download the modified LDO CoreXY Parts on Printables
CoreXY Structural Parts
Unfortunately, the Prusa XL will still be shipped in 2025 with PETG parts in the CoreXY part, even though Prusa recommends printing the parts in PC-CF on Printables.com.
This mod is significantly more stable and rigid than the original. The pulley axes are also firmly attached.
Especially recommended when using an enclosure. It works with the new Washers.
Recommendation: ⚠️ Recommended for enclosed printers
Problem
Despite Prusa recommending PC-CF parts, the Prusa XL still ships with PETG CoreXY components.
Solution
Upgraded structural parts provide significantly higher rigidity.
Pulley axes are properly fixed, improving mechanical stability.
Additional notes
- Compatible with the newer washer design
- Especially relevant for enclosed printers
Verdict
A major structural improvement.
Not required for open-frame PLA printing, but strongly recommended for high-speed, enclosed or high-temperature setups.
Download the stronger modified CoreXY Parts on Printables
Anti-Overheating mods
In regions with high temperatures, the Prusa XL may experience overheating errors. IPIND 3D has already provided suitable solutions for this.
Recommendation: ⚠️ Environment-dependent
Problem
In warm climates or poorly ventilated rooms, the Prusa XL may trigger overheating errors during long prints.
Solution
IPIND 3D provides proven airflow and thermal management solutions.
Verdict
Only necessary in hot environments.
If you never see thermal warnings, you do not need this.
Download the anti-overheating mod for the Heatbed Controller on Printables
Download the anti-overheating mod for the Buddy Cover on Printables
Tools
Here is a list of some important and useful tools:
Daily Tools
Download Bowden Speed Loader on Printables
Download Optimized Bed Scraper on Printbales
Download Filament Cutter 45° on Printables
Calibration Tools
Download TORQUEY – Prusa XL Edition – Torque Wrench for the Nozzle on Printables
Download Prusa XL Multi-Tool Manual Calibration on Printables
Download the Pressure Advance Linear Advance Calibration Test on Printables
Download Perfect First Layer for Prusa XL with handle on Printables
Download Prusa XL – Toolchanger Stresstest on Printables
Download Prusa XL – Belt Tension Equalization Gcode on Printables
My Prusa XL Printables Collection
I also have a collection on Printables.com: https://www.printables.com/@INVESTEGATE/collections/822155
Final Assessment
This list focuses exclusively on functional, tested upgrades.
If a mod does not provide a clear technical benefit, it is intentionally excluded.
No hype.
No cosmetic mods.
Only changes that actually improve the Prusa XL.
If you think that an important upgrade, mod or tool is missing, please write it in the comments below 🙂
I think you should really add the Heat Bed Controller cover “cooler” (https://www.printables.com/model/1286108-improved-prusa-xl-heat-bed-controller-cover-remix) and the Buddy Cover colling mod as well (https://www.printables.com/model/859870-improved-prusa-xl-buddy-cover)
Both have taken my printer’s uptime/reliability so much higher…
Hey & thank you 🙂
Where do you live? I’ve heard about this mod a lot, but I’ve never had any problems with it. The mod probably only makes sense for warm to hot countries. It doesn’t get warmer than 26°C in my printing room.
A few comments:
1. I have doubts about the bedleveling brush. I have installed it and the gcode. For the the bed leveling cleaning to be effective, the brushing needs to occur while the nozzle is hot and before the first home, otherwise the ooze gets deposited on the build plate as part of the homing process and messes up the z homing. But for the positioning to be effective the position needs to be correct, so the home has to happen first. In my observations, the brush doesn’t really accomplish anything, although the idea is fantastic.
2. I live in San Francisco, California, USA. My print room with only the one XL got above 28 for a week and I was printing ABS. The buddy box got too hot and the printer stopped waiting for it to cool down. I agree with Brian Montini that the Buddy Cover and Heat Cover cooler should be recommended for people whose print room gets too warm. And I’d love to see your analysis of the different options and which you ultimately recommend.
3. I see you recommend two different Nozzle Fan Ducts. Do you have opinions or data on which one to use for which circumstances?
Hey 🙂 Your point is correct. But hot cleaning vs. accurate homing is a conflict. Because you have to home first, so the print know its place.
Prusa changed the start G-code in the latest update. Therefore, it’s not working as expected unless you adjust the G-code separately. I already have a solution for this, but I need to test it again when I have time.
28 °C ambient plus ABS is enough to trigger Buddy Box thermal protection. That’s expected behavior. A Buddy Cover with active cooling should be clearly recommended for warm rooms.
The first fan duct is slightly better than the other, but only minimally. Nevertheless, I’ve now indicated which one I recommend.