Prusa i3

First conceived in 2009, RepRap Mendel printers[4] were designed to be assembled from 3D printed parts and commonly available off-the-shelf components (referred to as "vitamins," as they cannot be produced by the printer itself).[5] These parts include threaded rods, leadscrews, smooth rods and bearings, screws, nuts, stepper motors, control circuit boards, and a "hot end" to melt and place thermoplastic materials.[6]

Josef Průša, a core developer of the RepRap project who had previously developed a PCB heated "bed" on which parts are printed,[7] adapted and simplified the RepRap Mendel design, reducing the time to print 3D plastic parts from 20 to 10 hours, and including 3D printed bushings in place of regular bearings.[8] Released in September 2010, the printer was dubbed Prusa Mendel by the RepRap community, rather than by Průša himself. According to the RepRap wiki, "Prusa Mendel is the Ford Model T of 3D printers."[9]

Prusa Mendel design iteration 2 was released in November 2011, with upgrades including snap-fit parts (no glue required), improvement to the belt drive, and use of LM8UU linear bearings.[10] Fewer tools were needed to construct and maintain this version.

In May 2012, Průša released a major redesign, focused on ease of construction and use, and no longer structured around the simplest available common hardware as previous RepRap printers were.[11] The Prusa i3 design replaced the threaded-rod, triangular frame construction with a single-piece water jet cut aluminium vertical frame to improve rigidity and motion accuracy. It used a single piece, food safe stainless steel hot end called the Prusa Nozzle which printed with 3mm filament, and used M5 threaded rods instead of M8.[12][13][14][15][16] Realizing that people were interested in buying complete kits of parts, Průša released a kit version in 2015 called the Original Prusa i3, sold through his company Prusa Research.[1] This was soon supplanted by a variant using smaller 1.75mm filament.[17]

Průša released the Prusa i3 MK2 in May, 2016. It was the first hobby printer with mesh bed leveling and automatic geometry skew correction for all three axes. Features included a larger build volume, custom stepper motors with integrated lead screws, a non-contact inductance sensor for auto-leveling, and a rewritten version of the Marlin firmware.[18][19][20] Other new features include a polyetherimide print surface, Rambo controller board and an E3D V6 Full hotend.[21][22] The Prusa MK2 became the first RepRap printer to be supported by Windows 10 Plug-and-Play USB ID.[23]

In March 2017, Průša announced on his blog[24] that the revised Prusa i3 MK2S would ship in place of the Prusa i3 MK2. Enhancements cited include U-bolts to hold the LM8UU bearings where cable ties had been used, higher quality bearings and rods, an improved mount for the inductance sensor, improved cable management, and a new electronics cover. An upgrade kit was offered to owners of the MK2 to add these improvements.

In September 2017, Prusa i3 MK3 was released,[25] marketed as "bloody smart". Upgraded features included:[26] a sturdier Y axis, a new extruder with double sided Bondtech drive-gears, quieter fans with RPM monitoring, faster print speeds, an updated bed leveling sensor, a new electronics board named "Einsy", quieter stepper motors with 128 step microstepping drivers and a magnetic heatbed with interchangeable PEI-coated steel sheets. The MK3 runs on 24V instead of 12V, so all the electrical components were updated to 24V variants. The printer also offers dedicated sockets to connect Raspberry Pi Zero W running open source OctoPrint software for wireless printing, and offers a custom Octoprint fork for the Prusa i3.

Ease of use features included a filament detector, allowing users to load filament just by inserting it, and which can pause the print if the filament is jammed or runs out; error-correcting stepper motor drivers which can handle skipped steps automatically, preventing layer shifts; and recovery from power outages. The ambient temperature sensor both confirms suitable environment temperature and detects overheated electrical connections on the main board.

Existing MK2 and MK2S users were offered a $199 partial upgrade named MK2.5, limited to features which are cheaper to upgrade. After negative feedback from the community, Prusa made available a more expensive $500 MK2S to MK3 full upgrade.

In February 2019, Prusa i3 MK3S was released, along with the Multi Material Upgrade 2S (MMU2S), which allows selecting any of 5 different materials for printing together automatically.[27] MK3S changes include a simplified mechanical filament sensor, improved print cooling, and easier access to service the extruder.

Further changes came with a running change in November, 2020 to the Prusa i3 MK3S+.[28] This model has a revised bed leveling sensor and minor parts changes.

• In 2012, Josef Průša received honors from the governor of the Vysočina Region in the Czech Republic for his accomplishments in technology.[29]
• In February 2014 he was featured on the cover of Czech Forbes magazine as one of the 30 under 30 list.[30]
• The MK2 and MK2S printers both won Best Overall 3D Printer awards from Make: Magazine.[31]
• Deloitte placed Prusa Research at the top of the 2018 Deloitte Technology Fast 50 as the fastest growing company in Central Europe.[32][33]
• The MK3 was named FFF 3D printer of the year for 2019 by 3D Printing Industry.[34]
• Průša was again featured on the cover of the Czech edition of Forbes in 2019 for his leadership at the now billion-koruna company.[35]
• All3DP named the MK3 Best 3D Printer of 2018, and the MK3S Best 3D Printer of 2020.[36][37]

With all aspects of the Prusa i3 series design freely available under open source and open hardware terms, many vendors have released copies, variants, and upgrades in assembled and kit form. Rather than compete directly with these, Prusa Research's strategy is to pursue continual refinement of its designs.[41]

i3 variants are made with many different types of frames. These include a single sheet frame cut from steel, acrylic (laser cut or CNC milled), medium-density fibreboard box frames and Lego.[42][43][44][45] Many printer enthusiasts, as well as manufacturers of "clone" printers, assemble frames from inexpensive aluminum extrusion.[46][47]

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  A Prusa i3 with a standard metal frame.
• 
  A Prusa Xi3 with an acrylic frame.
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  A Prusa i3 with a plywood box frame.
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  A Prusa i3 with a melamine-resin particle board frame.

Beyond the standard Prusa i3 filament extruders, others have created aftermarket extruders and enthusiast tool heads, including a MIG welder and a laser cutter.[48][49][50] Průša offered a collection of functional cooking tools and programs under the name "MK3 Master Chef Upgrade" as an April Fools' Day gag in 2018.[51]

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  A partially printed single-colour object showing the infill created to reduce the amount of plastic used.
• 
  A 3DBenchy created on a Prusa i3 using a color-mixing hot end.