Prunt Board 3 is a 3D printer control board featuring six TMC2240 stepper drivers, two 15A heater outputs, four fan outputs, four thermistor inputs, and four endstop inputs, designed for smoother and quieter operation.
The board offers enhanced ESD protection compared to models like Duet 3 Mini 5+ and BTT SKR 3 EZ, and supports hardware-accelerated step generation. The real advancement lies in the Prunt firmware and server, which utilize a 31-phase velocity profile for smoother operation and improved print quality over Klipper or Marlin firmware. Let’s examine the hardware details.
Prunt Board 3 specifications:
- 6x TMC2240 stepper drivers, capable of running at 3A with minimal airflow
- 2x 15A heater outputs with short circuit protection (1.3 µs response time)
- 4x tachometer inputs
- Fan outputs
- 4x fan outputs for 2, 3, and 4-pin fans, up to 2A with short circuit protection
- Individual current limit per output
- Hardware counters for high-speed fan tachometers
- 4x thermistor inputs
- Buffered to reduce noise and increase maximum ADC sample rate
- Support PT1000 and common NTC thermistors with short circuit protection
- 4x endstop inputs
- Input OVP – Fully protected
- Power OVP – Diode protection
- Dedicated power rail
- Software or hardware-powered step generation for precise timings and step rates
- Host interface – Fully isolated USB Type-B port
- Power Supply – TBD
- Dimensions – 144 x 117 mm
Prunt firmware centers on G4 motion profiles rather than G1 profiles:
Popular 3D printer motion controllers like Klipper, Marlin, and RepRapFirmware use 3-phase G¹ tangential motion profiles with a trapezoidal velocity curve. This method can negatively impact print quality and cause wear and tear due to instantaneous acceleration changes.
Some controllers use a 7-phase “s-curve,” which is an improvement but still not physically possible.
Prunt Board 3 advances with a 31-phase velocity profile, resulting in smoother motion. The Prunt motion controller lets you set tangential limits for each derivative individually.
The controller supports advanced corner blending with a degree-15 Bézier curve, enhancing print quality and reducing noise.
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