Prusa CORE One L: power, precision, and large format in a single machine

Recently, Prusa held an event full of unexpected news. Among them, we find the new Prusa CORE One L, which, although it may seem like a minor update, could actually be more significant than it appears at first glance.

Image 1: Prusa Core One L. Source: Prusa3D

New model or statement of intent

Over the past two years, we have witnessed a resurgence of FDM technology. The implementation of input shaper technology has been a revolution in terms of printing speed, automatic material change systems have opened the door to multicolor and multi-material printing, and FDM 3D printers have evolved from relatively simple machines to incorporating the most advanced technologies. This has sparked a battle among manufacturers, mainly Asian and clearly led by Bambulab, to introduce increasingly faster printers, more efficient multi-material systems, and cloud platforms with more advanced functions.

This manufacturers’ race has driven forward the development of FDM technology, but it has also turned FDM 3D printers into consumer devices aimed at a general audience, where the priority is to add new technologies even when many of them have not yet reached the necessary level of maturity to demonstrate their functionality and reliability.

Image 2: Bambulab H2S. Source: Bambulab

With the introduction of the new Prusa CORE One L, Prusa reaffirms its position of not taking part in this race, staying true to its principles. It is clear that Prusa’s goal is not to offer the printer with the highest number of features and technologies, but rather the most reliable, safe, productive, and long-term supported machine.

The consolidation of a new platform

For a long time, Prusa printers from the MK series earned a reputation for being the most reliable, easy-to-repair, and best long-term supported printers on the market. Despite being aimed at the general public, they became the preferred choice for many companies and professionals. This was the result of a simple but brilliant design principle: start from a modular design (the i3 platform) and, as technology advances, only incorporate mature technologies that provide a tangible improvement in functionality or reliability. This allowed each new MK series model to be more reliable and productive than its predecessor and offered easy upgrade paths to newer models.

Image 3: Prusa Mk4S. Source: Prusa3D

However, with the arrival of input shaper technology and the professional sector’s demand for new technical materials, the i3 platform began to show certain limitations. This is why Prusa developed the Core One printer, a new platform with a coreXY structure and a fully enclosed design, allowing further performance improvements and focusing on a professional audience. The new Prusa CORE One L represents the consolidation of this new platform and demonstrates its potential to become what the Prusa Mk series once was: the standard in reliability, safety, and productivity.

Innovative solutions for reliability

The new Prusa CORE One L not only represents a leap in build volume compared to the Core One but also introduces new features, many of which are based on unconventional yet far more reliable solutions.

For example, the new Prusa CORE One L features an automatic opening and closing system for the ventilation grille. However, the printer does not include any new electronic components for this purpose. How is it achieved? Very simply: the print head itself opens it via an internal lever on the grille. This allows a previously manual task to be automated without the need for additional electronic systems, maintaining reliability (fewer components mean fewer possible failures) and reducing the risk of operational errors.

Image 4: Ventilation grille opening system. Source: Prusa3D

Another uncommon solution is the new system developed by Prusa for active chamber heating. Instead of using a PTC heater like most manufacturers—which can pose a significant safety risk—Prusa has developed a new AC-powered heated bed that integrates fans and deflectors to use the heat from the underside of the bed to actively heat the chamber up to 60 ºC. Using a single heating system for both the bed and the chamber reduces the risk of failure and increases safety by eliminating PTC heaters.

Image 5: New active temperature control system. Source: Prusa3D

Moreover, this new bed allows for an incredibly uniform temperature distribution with deviations of only 2 ºC across 99% of the surface.

Image 6: Thermography of the new Core One L bed (left) and a competitor’s printer (right). Source: Prusa3D

The new CORE One L also doubles the print volume compared to the Core One, with minimal size increase and even reduced weight thanks to the use of aluminum panels instead of steel.

Image 7: Size comparison Core One L and Core One. Source: Prusa3D

Safety as a fundamental principle

Using an AC-powered bed offers many advantages in terms of heating speed and power, but it also introduces greater safety complexity that many manufacturers overlook.

This is why the inclusion of the new bed also involves a complete redesign of the printer’s electrical power management systems. The CORE One L can detect input voltage, distinguishing between 110 V and 230 V networks, and configure the heated bed accordingly. Unlike most manufacturers, it does not perform a simple binary check but rather analyzes the voltage waveform in real time—a much more precise and safer method.

Additionally, the printer features a multilayer safety architecture that actively monitors fault currents and immediately cuts power if any leakage is detected, similar to how a household circuit breaker works. One of the most critical points, the bed power supply, uses a redundant system composed of a TRIAC and a relay, ensuring that if one component fails, the other will still cut off power to the circuit.

Privacy, a (rare) value

Cloud printer management has greatly improved convenience and productivity, but it also introduces privacy risks. Using cloud control systems means that all designs and data sent to the printer are transmitted and potentially stored on external company servers—companies about which we often lack information or assurance regarding how they might use such data. Moreover, data stored in the cloud is always susceptible to interception and distribution or sale through the Deep Web. This poses a critical risk to the protection of companies’ intellectual property and even to national security in the case of critical infrastructures or defense organizations.

In contrast to the trend of manufacturers forcing users to rely on their cloud platforms or connect 3D printers to the internet for setup, Prusa offers a completely optional cloud solution. The Core One L can be used entirely offline, without network connection or user account setup, without losing any functionality.

Furthermore, the electronic boards, like the printers themselves, are manufactured in Europe at Prusa’s own factory, preventing third parties from introducing software or firmware modifications that could pose security risks.

Image 8: Encrypted and certified USB included with Core One L: Critical Infrastructure Edition

For the most demanding security scenarios, such as defense agencies or critical infrastructure, Prusa has launched the Core One L: Critical Infrastructure Edition, a version of the CORE One L featuring a custom board without Wi-Fi circuitry, an encrypted and certified USB drive, and volatility documentation.

Precision and productivity

Over the past year, both the Core One printer and the Prusaslicer software have received numerous updates focused primarily on achieving the highest possible precision and consistency without sacrificing print speed. As a result, the Core One has become one of the most precise and consistent FDM 3D printers on the market today. All this knowledge and functionality have been carried over to the Core One L from day one. Combined with the fact that it is delivered fully assembled and calibrated, companies can begin reliable, consistent production immediately.

Image 9: Dimensional deviation comparison of a part printed with Core One (left) and a competitor’s printer (right). Source: Prusa3D

With the new Prusa CORE One L, Prusa offers a mature, professional solution born from years of continuous improvement, delivering reliability, safety, and productivity for professionals seeking a long-term supported professional tool.