Josef Prusa Unleashes Speed for the MK4 3D Printer
The 3D printing pioneer calls “bullshit” on marketing from the competition.

Josef Prusa announced the consumer ready, stable release of Input Shaper Firmware for the Editor's choice Prusa MK4 printer last night. The long awaited improvement allows users to crank up the speed and acceleration on their MK4 and MK3.9 printers.
The 3D printing pioneer and industry leader defended his printers in an email to subscribers, saying that it’s difficult to compare the speeds of various machines.
“And how fast your MK4 will be after update? Well... It's hard to say. Comparing the speed of 3D printers is a tricky job and you can't just pick up one number and sort the printers from the fastest to the slowest. That's why I've prepared an article to tell you why these numbers are not much more than a marketing bullshit.”
~Josef Prusa
He also announced an alpha version of Input Shaper for the Prusa Mini, a machine that now has more competition in the form of Bambu Lab’s newest A1 Mini. The A1 Mini, revealed this morning, is a superfast bedslinger with a small build volume and a similar cantilever design.
When the Prusa MK4 released in late April it was missing an important part of the puzzle – Input Shaping and Pressure Advance. Inspired by Klipper, these functions are critical for high speed printing as they calm imperfections caused by rapid movements and vibrations. An alpha version of the firmware was released about a month later.
Directions on updating the MK4’s firmware is located in the Prusa Knowledge Base.
Prusa isn’t saying precisely how fast the new firmware will make his machines, but he explained in a blog post that there are too many variables involved in fast printing. These are print speed, acceleration, volumetric flow, nozzle size and more.
“For marketing purposes, this is all way too complicated. So, instead, companies pick one or two numbers. Typically the travel speed, the print speed of infill, or the acceleration for printing infill,” Prusa said. He concluded that print speed is just one aspect of the user’s experience and that consumers should also factor reliability, tech support, community, open-source software, upgradability and continuous support after years of release.
We upgraded our Tom’s Hardware MK4 after the announcement and found that it could now print a 26-minute Speed Boat Rules Benchy with new acceleration speeds reaching 4000mm/s and print speeds held at a respectable 200mm/s.
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Denise Bertacchi is a Contributing Writer for Tom’s Hardware US, covering 3D printing.
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peachpuff We upgraded our Tom’s Hardware MK4 after the announcement and found that it could now print a 26-minute Speed Boat Rules Benchy with new acceleration speeds reaching 4000mm/s and print speeds held at a respectable 200mm/s.
What was the before time? How did they get 20min here? tcwrEi_CcMEView: https://www.youtube.com/watch?v=tcwrEi_CcME
Get the feeling Prusa is a bit salty here and seeing his sales fly away to bambu labs and other core xy printers.
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