Josef Průša, the Founder of Prusa Research, dropped a bombshell on the 3D printing community Wednesday morning. After teasing a video on Twitter of a fast printing Benchy on Tuesday, he announced the long awaited Original Prusa MK4 was ready to ship. Several hundred prebuilt MK4s were in stock and ready to purchase for $1099 with a $799 DIY kit on the way.
The announcement took Twitter by storm. Fans of the popular orange printers have suffered through a drought of upgrades, with no sign of relief despite newcomers AnkerMake and Bambu Lab appearing on the scene in 2022 with eye-popping speed. The last update to the flagship series was the MK3S+ in late 2020, which is still one of the best 3D printers. The original MK3 was released in 2017.
I was invited to chat with Průša to follow up on the launch of the MK4. “The release was awesome, better than any Kickstarter you’ve seen,” he said. Průša declined to state how many units are ready for shipping, but said thousands have been ordered. “No one was expecting it this close to shipping the XL.”
“It’s surreal for us,” he added. Průša said they’ve been using the MK4 for the past year, putting the machines through practical testing around the office and within their print farm. When asked how they’ve managed to keep the coveted new printer under wraps, he smiled and said, “we’re good at hiding.”
Průša explained that the MK4 needed to be released on the heels of the more expensive Original Prusa XL tool changer because they share a lot of hardware and firmware. He was concerned that his competition would tear into the XL looking for secrets and possibly copycat the MK4 before it could get out the door.
It’s widely known that Průša is a staunch supporter of the Open Source movement, but he has concerns. Companies like his practice open source to share ideas and innovations, helping each other grow by combining their knowledge. He wrote a blog post about his thoughts on March 29, hoping to spur communication and ultimately devise a new license for the 3D printing community.
Prusa lamented the recent lack of innovation in 3D printing, stating that the community was more vibrant just five years ago. “Everyone is doing a rehash of the i3; no one is trying new things,” he said. He dismissed his competitor’s speedy Core XY machines as “just Voron with a cloak.”
He admits his new MK4 might look very similar to the MK3, which has become an industry standard. He explained that most of the changes are under the hood. Průša is most proud of the 32-bit STM32-powered xBuddy board which handles all the printer’s functions, including Prusa Research’s new firmware which handles Input Shaping and Pressure Advance. Other fast 3D printers, like the Biqu Hurakan, require two separate boards and an awkward internal placement to do the same job.
The xBuddy board also includes built-in Ethernet, Wi-Fi, a USB-C port and ports for an optional accelerometer and multi-material unit.
A “hidden gem” that Průša feels users will really enjoy is the new load cell sensor, which his engineers have also installed on the recently released Original Prusa XL. The analog sensor helps the printer lay down a perfect first layer automatically. It measures the distance between the nozzle and the print sheet and calculates any required Z offset. He said that other companies have been using similar technology, but not as well as they have. It requires no input from the user, and completely eliminates the need for Live Adjust Z.
To speed up prep time, the sensor only examines the portion of the bed that will be printed on.
Customers who have pre-ordered the massive Original Prusa XL tool changer can avoid buyer’s remorse and switch to a MK4 instead. If you already have an MK3S+ you can purchase a variety of upgrade options.
“The upgrade is a nice thing to do for customers,” he said, “it will save on e-waste. And you can re-program the old board like an Arduino for making projects.”
Průša recommends the MK3.5 upgrade as the “best bang for your buck.” This upgrade is $249 and contains the xBuddy board and a new LCD screen, giving your old printer access to Input Shaper and Pressure Advance for high speed printing.
He doesn’t recommend the full upgrade kit, which also includes the Nextruder and new stepper motors, but felt the need to include the option because someone will ask for it. The full upgrade kit is $589, roughly half the price of a complete MK4.
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Denise Bertacchi is a Contributing Writer for Tom’s Hardware US, covering 3D printing.