Features

Klipper has several compelling features:

• High precision stepper movement. Klipper utilizes an application processor (such as a low-cost Raspberry Pi) when calculating printer movements. The application processor determines when to step each stepper motor, it compresses those events, transmits them to the micro-controller, and then the micro-controller executes each event at the requested time. Each stepper event is scheduled with a precision of 25 micro-seconds or better. The software does not use kinematic estimations (such as the Bresenham algorithm) - instead it calculates precise step times based on the physics of acceleration and the physics of the machine kinematics. More precise stepper movement translates to quieter and more stable printer operation.

• Best in class performance. Klipper is able to achieve high stepping rates on both new and old micro-controllers. Even old 8bit micro-controllers can obtain rates over 175K steps per second. On more recent micro-controllers, rates over 500K steps per second are possible. Higher stepper rates enable higher print velocities. The stepper event timing remains precise even at high speeds which improves overall stability.

• Klipper supports printers with multiple micro-controllers. For example, one micro-controller could be used to control an extruder, while another controls the printer's heaters, while a third controls the rest of the printer. The Klipper host software implements clock synchronization to account for clock drift between micro-controllers. No special code is needed to enable multiple micro-controllers - it just requires a few extra lines in the config file.

• Configuration via simple config file. There's no need to reflash the micro-controller to change a setting. All of Klipper's configuration is stored in a standard config file which can be easily edited. This makes it easier to setup and maintain the hardware.

• Klipper supports "Smooth Pressure Advance" - a mechanism to account for the effects of pressure within an extruder. This reduces extruder "ooze" and improves the quality of print corners. Klipper's implementation does not introduce instantaneous extruder speed changes, which improves overall stability and robustness.

• Klipper supports "Input Shaping" to reduce the impact of vibrations on print quality. This can reduce or eliminate "ringing" (also known as "ghosting", "echoing", or "rippling") in prints. It may also allow one to obtain faster printing speeds while still maintaining high print quality.

• Klipper uses an "iterative solver" to calculate precise step times from simple kinematic equations. This makes porting Klipper to new types of robots easier and it keeps timing precise even with complex kinematics (no "line segmentation" is needed).

• Portable code. Klipper works on ARM, AVR, and PRU based micro-controllers. Existing "reprap" style printers can run Klipper without hardware modification - just add a Raspberry Pi. Klipper's internal code layout makes it easier to support other micro-controller architectures as well.

• Simpler code. Klipper uses a very high level language (Python) for most code. The kinematics algorithms, the G-code parsing, the heating and thermistor algorithms, etc. are all written in Python. This makes it easier to develop new functionality.

• Custom programmable macros. New G-Code commands can be defined in the printer config file (no code changes are necessary). Those commands are programmable - allowing them to produce different actions depending on the state of the printer.

• Builtin API server. In addition to the standard G-Code interface, Klipper supports a rich JSON based application interface. This enables programmers to build external applications with detailed control of the printer.

Additional features

Klipper supports many standard 3d printer features:

• Works with Octoprint. This allows the printer to be controlled using a regular web-browser. The same Raspberry Pi that runs Klipper can also run Octoprint.

• Standard G-Code support. Common g-code commands that are produced by typical "slicers" are supported. One may continue to use Slic3r, Cura, etc. with Klipper.

• Support for multiple extruders. Extruders with shared heaters and extruders on independent carriages (IDEX) are also supported.

• Support for cartesian, delta, corexy, corexz, rotary delta, polar, and cable winch style printers.

• Automatic bed leveling support. Klipper can be configured for basic bed tilt detection or full mesh bed leveling. If the bed uses multiple Z steppers then Klipper can also level by independently manipulating the Z steppers. Most Z height probes are supported, including BL-Touch probes and servo activated probes.

• Automatic delta calibration support. The calibration tool can perform basic height calibration as well as an enhanced X and Y dimension calibration. The calibration can be done with a Z height probe or via manual probing.

• Support for common temperature sensors (eg, common thermistors, AD595, AD597, AD849x, PT100, PT1000, MAX6675, MAX31855, MAX31856, MAX31865, BME280, HTU21D, and LM75). Custom thermistors and custom analog temperature sensors can also be configured.

• Basic thermal heater protection enabled by default.

• Support for standard fans, nozzle fans, and temperature controlled fans. No need to keep fans running when the printer is idle.

• Support for run-time configuration of TMC2130, TMC2208/TMC2224, TMC2209, TMC2660, and TMC5160 stepper motor drivers. There is also support for current control of traditional stepper drivers via AD5206, MCP4451, MCP4728, MCP4018, and PWM pins.

• Support for common LCD displays attached directly to the printer. A default menu is also available. The contents of the display and menu can be fully customized via the config file.

• Constant acceleration and "look-ahead" support. All printer moves will gradually accelerate from standstill to cruising speed and then decelerate back to a standstill. The incoming stream of G-Code movement commands are queued and analyzed - the acceleration between movements in a similar direction will be optimized to reduce print stalls and improve overall print time.

• Klipper implements a "stepper phase endstop" algorithm that can improve the accuracy of typical endstop switches. When properly tuned it can improve a print's first layer bed adhesion.

• Support for measuring and recording acceleration using an adxl345 accelerometer.

• Support for limiting the top speed of short "zigzag" moves to reduce printer vibration and noise. See the kinematics document for more information.

• Sample configuration files are available for many common printers. Check the config directory for a list.

To get started with Klipper, read the installation guide.

Step Benchmarks

Below are the results of stepper performance tests. The numbers shown represent total number of steps per second on the micro-controller.

Micro-controller	Fastest step rate	3 steppers active
16Mhz AVR	154K	102K
20Mhz AVR	192K	127K
Arduino Zero (SAMD21)	234K	217K
"Blue Pill" (STM32F103)	387K	360K
Arduino Due (SAM3X8E)	438K	438K
Duet2 Maestro (SAM4S8C)	564K	564K
Smoothieboard (LPC1768)	574K	574K
Smoothieboard (LPC1769)	661K	661K
Beaglebone PRU	680K	680K
Duet2 Wifi/Eth (SAM4E8E)	686K	686K
Adafruit Metro M4 (SAMD51)	761K	692K
BigTreeTech SKR Pro (STM32F407)	922K	711K

On AVR platforms, the highest achievable step rate is with just one stepper stepping. On the SAMD21 and STM32F103 the highest step rate is with two simultaneous steppers stepping. On the SAM3X8E, SAM4S8C, SAM4E8E, LPC176x, and PRU the highest step rate is with three simultaneous steppers. On the SAMD51 and STM32F4 the highest step rate is with four simultaneous steppers. (Further details on the benchmarks are available in the Benchmarks document.)