Prusa Knowledge Base

All terms

1.75 mm

3D printers mainly use two different diameters (thickness) of filament: 2.85 mm (commonly called 3 mm) and 1.75 mm. Worldwide, the 1.75mm version is more common. All of our Original…

Belt tension

For optimal print quality, the belts in your Prusa printer must be correctly tensioned. Loose belts can cause issues like layer shifting, ghosting, or irregular shapes in prints. Belt…

Blade

Inside the MMU2S selector, cutting potential strings on the filament upon filament change. From firmware 3.9.0 onwards, it is possible choosing to cut the filament from the printer…

Bondtech gears

This is the filament-pulleys or hobbed pulleys on all Original Prusa MK3/S and MK2.5/S. The set includes two gears (one with a set screw and one without screws), two bearings,…

Bowden tube

A 4x2x360 PTFE tube that connects the MMU2S unit to the printer's extruder. It is secured to the extruder and MMU2S selector by Festo QSM-M5 fittings. The tube may be orange or…

Buddy board

Our own design of a 32-bit controller board for the Original Prusa MINI. Works on 24V and uses Trinamic drivers for motors, allowing for super silent printing, but also includes…

Cantilever

Metal part attached to the tower which is used to mount the print platform of the Original Prusa SL1.

Check the cables

Inspect the wiring visually, look for pinched, broken or scratched cable sleeves. (unwrap the cable from the sleeve if necessary). Check the cable plugs on both ends by holding…

Chimney (IR-sensor-holder-mmu2s)

Holder of IR filament-sensor on the MMU2S extruder and part of the filament sensor mechanism. It may need to be adjusted during the IR sensor calibration. The 'chimney' is not…

Control buttons

Controls functions and position of the selector. The middle button will load the filament to the FINDA/Selector and back. The right and the left button moves the selector left…

Controller board (MMU2S)

Main-board for the MMU2S unit, with control buttons, micro USB input, reset button, and input for motors, FINDA, power cable, and printer signal cable.

Curing / solidifying

Curing is the process of solidifying liquid resin using UV light. Sunlight contains UV light and it can cause the liquid resin to solidify/cure. The recommended curing time per…

Einsy RAMBo board

Mainboard of the MK3 and MK3S. 8-bit logic board called Einsy RAMBo. Compared to its predecessor, the miniRAMBo, it works on 24V. Uses Trinamic drivers for motors, allowing for…

Ethernet port

Can be used to connect the printer to the local network for remote control, transfer of files, and remote monitoring. It is located on the back of the device and is compatible…

Extruder (i3)

The print head also is known as an extruder. It is the part of a printer consisting of a hotend w/nozzle, hobbed pulley, idler, a nozzle fan (print fan), hotend fan, P.I.N.D.A.-probe,…

Extruder / Extruder motor (Mini)

As opposed to 3D printers like MK2 or MK3S, on the Original Prusa MINI, the extruder motor is not installed on the print head, moving along the X-axis. Instead, it’s fixed on the…

Extruder PTFE tube (Bowden-tube)

Leads the filament strand from the extruder into the print head / nozzle. Inspect it from time to time to make sure there is no debris inside that would prevent the filament strand…

F.I.N.D.A. sensor

Filament-sensor of the MMU2S selector. When the filament passes through the selector, it lifts a metal ball. The metal ball triggers the F.I.N.D.A. inductive sensor.

FEP foil

Special transparent film installed in the bottom of the Original Prusa SL1 resin tank. FEP film should never be cleaned with IPA (Isopropyl alcohol). Please refer to the SL1 Handbook regarding…

FFF/FDM

Stand for Fused Filament Fabrication (FFF) and Fused Deposition Manufacturing (FDM) and is the general term 3D printing using spools of polymer string (filament). "FDM" is a trademarked…

Filament

The term for plastic/polymer provided on a spool. The filament used with the Original Prusa i3 series and MINI has a diameter of 1.75 mm. Prusa Research manufactures the filament…

Filament buffer

Filament-organizer mounted at the printer's base. The buffer prevents the filaments to tangle by having a separated layer/compartment of each of them. It also prevents the spool…

Filament tip

Before inserting the filament into the machine, always cut the tip. There are two ways you can do that: Cut the filament at a 45° angle Grab the filament about 10 cm from its…

Firmware

The "operating system" of the printer. Make sure your printer is always running the latest firmware, new versions bring extra features and bug fixes. You can find the latest firmware…

Flexible steel sheet

Removable printing-surface placed on the magnetic heat bed. Present on MK2.5/S, MK3/S, and MINI. The smooth steel sheet is suitable for materials with lower adhesion (like PLA…

Heatbed

The commonly used term for the heated surface being printed on by the 3D printer - needs to be covered in a material that the first layer will adhere to, like PEI (MK2S) or a Flexible…

Heater block

The aluminum block that contains the Nozzle, thermistor, and heater, on the hotend. It is attached to the rest of the hotend by the heatbreak.

Heater cartridge

The heater of the nozzle inserted into the heater block. Is 12V 40W for the Original Prusa MK2/S and MK2.5/S or 24V 40W for the Original Prusa MK3/S.

Heatsink

Heatsink assists in controlling the melt zone in a hotend. Must have a hotend fan blowing air through its fins.

Hollowing

Removing the inside of a model, only the shell will be printed. When hollowed, the model needs drainage holes to let excess resin escape. Hollowing and adding drainage holes can…

Hotend

Refers to the complex of metal parts found in the extruder. It is composed of the nozzle, heat break, heatsink, heater block, collet clip, PTFE tube, heater cartridge, and thermistor…

Hotend fan

The hotend fan blows air through the heatsink's fins. Should be oriented with its sticker facing the heatsink.

Idler motor

Rotates the idler, which in turn will place the bearing on top of the filament to be loaded/unloaded by the MMU.

Idler screw

M3x40 screw(s) intersects the extruder horizontally and has a spring on it. On the Original Prusa MK2S, idler screws should protrude by approximately 13 mm. On the Original Prusa…

Idler tension-screws

Two screws with springs on them applying pressure between pulley-body and idler-body. The top of the screw needs to be slightly below the surface of the pulley body. If the filament…

Indicator LEDs

Indicates filament position and unit status. The stable green LED indicates the position that the selector is on. The stable red LED indicates a work in progress in the MMU. More…

IR filament-sensor

Optical filament sensor on the extruder, introduced with the S-upgrade for the Original Prusa MK3/S and MMU2S.On the MK3/S, it is activated when the steel ball pushed the fs-lever…

Knob

The large black knob at the top of the cantilever. It is designed for easy mounting/dismounting of the print platform by screwing or unscrewing it. If it is not tightened, the…

LCD screen (Mini)

The LCD screen is used for the configuration of the 3D printer and accessing the printer's menu. Use the selector knob to scroll through the menus and confirm your selection with…

Lid

The orange-colored lid is made of acrylic and its layers protect the liquid resin from UV light (such as sunlight), which would otherwise cure it. It also protects the user from…

Liquid resin

Liquid photoreactive material used for printing in SLA 3D printers. It requires special care during handling. The SL1 uses 405 nm MSLA/LCD resins. If other types of 405 nm resins…

Live adjust Z

The "Live adjust Z" is a feature available on all Original Prusa printers based on the FFF technology, designed to further fine-tune (adjust) the distance between the tip of the…

Loadcell

A loadcell is a component that converts force or weight into an electrical signal. On our printers, it is part of the Nextruder, equipped on our Prusa CORE One, and Original Prusa…

M.I.N.D.A. sensor

Induction sensor for auto-leveling/mesh bed leveling. Accurately detect the metal in the flexible steel sheet.

Mesh bed leveling

Calibration procedure where the bed leveling sensor (P.I.N.D.A. or SuperPINDA) reads the beds and creates a virtual mesh which is used to compensate for skew or tilt in the assembly.

Micro USB port

Used for flashing the firmware on the MMU unit with the cable that is provided with the kit. The cable is common with Android smartphones, but must support data, not only charging.

MMU Idler

It rotates the printed part with bearings, applying pressure to the selected filament against the pulley. It must rotate freely in order for the filament change to work.

Nozzle

Extrudes the filament, creating your model. The standard nozzle for an Original Prusa FFF printer is a 0.4mm brass nozzle, for 1.75mm filament. This can be replaced with virtually…

Object / part manipulation panel

Whenever you have one or more objects selected, the Object manipulation panel appears in the right panel. Using the text inputs and buttons, you can quickly modify: Position Rotation Scale…

Octoprint

Octoprint is an open-source system for remotely controlling and monitor your printer. Start/stop/pause prints, change printing temperatures and settings while printing, stream…

Olive

Secures the Extruder PTFE in the tube fitting on the Original Prusa MINI. The "Olive" is installed using a special tool/jig. If it falls off, you may need to replace the whole…

Original Prusa MK2.5S

Upgrade for the Original Prusa MK2/S, which includes Bondtech gears, magnetic bed, flexible steel sheet, extruder design with Noctua fan, filament sensor, and more adopted from…

P.I.N.D.A. sensor

Prusa INDuction Autoleveling probe, is a vital component facilitating the calibration of our printers. There are 2 different versions: V1, used in MK2/S, and V2, used on MK2.5,…

Place on Face

First, select a model you wish to re-orient. Then press the F key or pick the Place on Face tool from the left toolbar. Multiple white planes will appear on the model. Clicking…

Power Button (SL1)

Turns the printer on or off. This button won’t disconnect the power supply. To cut off power completely, disconnect the power cord from the back of the printer.

Power switch

Turns the printer on and off. When the printer is not in use, turn it off using the power switch.

Print display

This display is part of the tilt assembly. It shows a mask (shape) of a single layer at a time, allowing UV light to pass through and solidify a single layer in a controlled manner.…

Print fan

Cools the printed object, improves print quality. Compatible with RPM monitoring. Fans with RPM monitoring have 3-4 wires.

Print head

Lightweight print head consisting of the hotend (printing nozzle), auto-leveling sensor, and two fans. Moves on the X-axis (left/right movement). The filament drive-motor was moved…

Print platform

An aluminum platform which, on the Original Prusa SL1, the object is printed on. Moves with the Z-axis and is secured by the knob.

Print speed

You can decrease (or increase) the print speed in two ways. The easiest way to do it is by rotating the knob next to the LCD screen during the printing process. Counterclockwise…

Pulley motor

The five hobbed pulleys for each filament are attached to the motor's shaft to be rotated when loading or unloading the filament. The correct filament is engaged by the MMU2S Idler.

Reset button

Hard-resets the unit independent of printer. It is located on the right side of the MMU unit, next to the micro USB port. If the MMU is reset during the print, the MMU will go…

SD card

The memory card that comes with the Original Prusa i3 printers. Used to get the files from your computer to the printer. Must be formatted to FAT32. The card needs to stay in the…

Selector

Movable part with the Bowden-tube, directing the selected filament to the extruder. Is moved by the Selector motor and holds the F.I.N.D.A. sensor.

Selector Knob (MINI)

The main control of the Original Prusa MINI. Rotate left/right to scroll through options, press the knob to confirm your selection.

Selector motor

Moves the Selector. The motor's shaft is a threaded rod that moves the selector by the trapezoid nut attached to the selector.

Simple, Advanced and Expert mode

The user interface changes in appearance depending on the mode you’re in. You can switch to a different mode using the buttons in the top right corner by going to Configuration…

SL1 file (.sl1)

A file containing printing instructions compatible with the SL1. SL1 files are created by slicing a 3D object using PrusaSlicer.

Spool holder

Allow for the spool to freely supply the printer with filament during printing. Should be placed near the printer, so the filament strand can enter the PTFE tube from below. The…

SuperPINDA

PINDA stands for Prusa INDuction Autoleveling probe, which is a vital component facilitating automatic calibration. It is an inductive probe compatible with our FFF printers. Unlike…

Tank

The container (vat) for liquid resin. It has a transparent bottom that allows UV light to pass through. The bottom of the tank is an FEP film, a consumable that will degrade after…

Thermistor

Temperature-sensor. Installed on both hotend and heatbed. The thermistor in the hotend is inside a cartridge to be inserted in the heater block and held by a screw. The thermistor…

Tilt

The general name for the whole bed with the motorized tilt function. The tilt mechanism has the print display attached to it, and it is moved by the tilt motor and connecting rod.

Tilt motor

The motor moving the tilt mechanism on the Original Prusa SL1.

Tooltips

Tooltips are a small blerb of information that will pop up when you hover over a word that is linked to a Tooltip entry. These tooltip entries also double as a glossary which will…

Touchscreen Display / Touch screen

The main control interface of the Original Prusa SL1. The capacitive touchscreen is used to navigate through the menus, start prints, adjust settings, or calibrate the printer.

Tower / Z-Axis (SL1)

The mechanism that raises and lowers the cantilever with the print platform along the Z-axis. The cantilever is secured with a ball screw.

Tube fitting

Found on both ends of the main PTFE tube (Bowden). In case filament gets stuck in the PTFE tube, use a spanner (included with the printer) to remove the fittings and the PTFE tube…

USB flash drive

A data storage device that accompanies the Original Prusa SL1 and MINI printers. Can be used to upgrade the firmware and to load print files on the printer. Must be formatted to…

USB port

Compatible with USB 2.0/3.0 flash drives (FAT32 filesystem). Used for reading print files (G-Codes) from the inserted drive and flashing the firmware.

USB port (SL1)

Used for reading SL1 print files from a USB drive and connect accessories, like the UV Calibrator for the print display.

UV LEDs

The UV LED panel emits UV light through the mask shown on the print display and solidifies (cures) the resin in the tank, creating the desired object layer by layer. Must be calibrated…

Variable layer height

This tool becomes available in the top toolbar after you select a model. It lets you print different regions of your model with a different layer height and smooth the transitions.…

Wipe-tower (Purge-tower)

Part of print, built up by purged material during filament/color changes. The purge is necessary to remove any traces of the previous color from the hotend and build up pressure…

xBuddy board

Our own design of a 32-bit controller board for the Original Prusa MK4/S, MK3.9/S, and MK3.5/S. It works on 24V, has Trinamic drivers for silent motor operation, and Wi-Fi/LAN…

Glossary