Sep 25, 2017 | By Benedict

Prusa Printers, Josef Průša’s popular RepRap 3D printer company, has released a new 3D printer. The Original Prusa i3 MK3 comes with a filament sensor, improved magnetic MK52 heatbed, and Trinamic2130 drivers with layer shift detection. It costs $749 (kit) or $999 (assembled).

When you consider just how little you have to pay these days for a fully assembled consumer 3D printer, it’s easy to wonder whether the RepRap community—comprising those enthusiastic makers building 3D printers from scratch with open source designs and components—has a particularly promising future.

It’s a doubt that surely inspired Josef Průša, the young pioneer behind the extremely popular Prusa RepRap 3D printer, to form a proper company selling 3D printers in both assembled and kit form.

Prague-based Prusa Printers may be a more commercial effort than those original RepRaps, but Prusa’s reputation has hardly been damaged as a result, with makers praising the quality of the 3D printers and obviously remaining keen to support one of their own.

The new Original Prusa i3 MK3

Prusa fans can now celebrate, because the company has just released the Original Prusa i3 MK3, around a year and half after the release of the Original Prusa i3 MK2. “It looks very familiar, but basically all the parts are new and improved,” Průša says. “Don’t be deceived by the familiar look!”

The MK3 comes with a raft of new features, but the overriding difference between this 3D printer and its predecessors is intelligence. With a number of sensors added to the printer, users are now far less likely to encounter printing errors, since the printer is now fully aware of how its print job is going.

One of those sensors is a filament sensor, not an uncommon sight on FDM machines these days, but a feature whose arrival on the MK3 will no doubt be celebrated by a great many RepRap devotees. Prusa’s sensor works by using lasers.

The MK3's filament sensor detects presence and movement

“Our optical filament encoder not only detects the presence of a filament, but also its movement,” Průša explains. “This means we can detect running out of the filament, pause the print, and ask the user to insert a new spool…But we can also detect stuck filament and offer the user a cold pull to clean the nozzle and continue the print.”

Of course, running out filament is just one of many ways you can mess up a print, and Prusa has sought to eliminate several other causes of failure, including power loss caused by accidental unplugging. The MK3’s “Power Panic” feature means the 3D printer can fully recover from a complete loss of power, without having to use batteries.

It works by using a sensor to detect mains voltage. In case of interruption, the 3D printer immediately shuts down the heatbed and extruder heating, leaving just enough power in the capacitors to store the position and park the print head away from print. When the power returns, printing can resume as normal.

But there are yet more sensors! To increase reliability, the Prusa team added sensors to the MK3’s cooling fans. These can measure RPMs and notify a user about any problem with the blades that could lead to print problems. The fan itself was made in collaboration with Austria-based cooling specialist Noctua, and emits virtually no noise.

The MK3's Noctua fans are overseen by sensors

The MK3 also shakes things up a little by increasing the number of thermistors from two to four. In addition to the extruder and heatbed thermistors, the new 3D printer adds one thermistor to measure the ambient temperature around the electronics, and another embedded in the P.I.N.D.A. 2 probe tip. Prusa says these additions help improve first layer accuracy.

Another big change here is the switch to 24V. This could be a slightly controversial move, because it effectively prevents MK2 users from upgrading fully to the MK3. Prusa has sought to offset this problem by offering an “MK2.5” version, which puts as many MK3 components as possible on the MK2 body, and the company is also offering discounts to certain MK2 buyers. However, despite this potential banana skin, the 24V allows the MK3 to show off its new EINSY (named after Einstein) RAMBo motherboard, developed in collaboration with Ultimachine.

Prusa says the EINSY is “the most advanced 3D printer board out there,” since it can monitor power and detect blown fuses. It also uses TRINAMIC drivers with all the features enabled and accessible through SPI.

These new Trinamic2130 drivers permit “absurd” 256 microstepping, and run quietly. They can detect lost steps and shifted layers, which allows them to rehome and continue printing without affecting the print.

The MK3's Trinamic2130 drivers allow for 256 microstepping

Other handy new features include a new Y axis and improved frame, a Bondtech extruder, and powder-coated PEI spring steel print sheet, made specifically for the printer’s crowning glory, its magnetic MK52 Heatbed, which is removable and tougher than previous incarnations.

“This was the hardest and longest development in Prusa Research history,” Průša boasts. “The new MK52 Magnetic HeatBed has embedded high curie temperature magnets inside. These hold special alloy spring steel sheets powder coated with PEI.”

The MK3's new Y axis (above) and PEI spring steel sheet

The MK3 will cost $749 in kit form, or $999 fully assembled. The MK2 will remain on sale, for $100 less than its previous price, and existing Prusa users will be given certain upgrade options.

Some users seem a little annoyed that this release has come out of the blue, having recently invested in the now-dated MK2. However, the overall reception appears to be one of great anticipation to get the MK3 up and running.

Original Prusa i3 MK3 new features:

  • Filament sensor
  • Power Panic
  • RPM-sensing fans and Noctua
  • Ambient thermistor and P.I.N.D.A 2 with thermistor
  • EINSY RAMBo motherboard
  • Trinamic2130 drivers with layer shift detection, faster and silent printing
  • New Y axis
  • Bondtech extruder
  • Magnetic MK52 Heatbed
  • Powder coated PEI spring steel print sheet
  • Ready for OctoPrint



Posted in 3D Printer



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