TLDR; A "How To" on upgrading a Duplicator i3 with modern 3D printer parts, firmware, and creativity. This post is still progress.

The Duplicator i3 is a common 3D printer that many now consider out dated. Instead of throwing it away and buying a new one, I took the challenge of upgrading and/or replacing parts to modernize it. There is also a lot of resources and parts still available.

The "To-Do" List

  • Glass bed

  • 1/16 to 1/32 steps for steppers. This provides cleaner and smoother prints.

  • Replace existing Melzi board with a MKS Gen 1.4 board. This could have been the standard RepRap Arudino Mega 2560 board as well.

    • JST 2 pin to 3 pin adapters for end stop connectors.

    • Add JST connector for extruder stepper

    • Marlin Firmware changes

      • Invert End stops

        #define X_MIN_ENDSTOP_INVERTING true // Set to true to invert the logic of the endstop.
        #define Y_MIN_ENDSTOP_INVERTING true // Set to true to invert the logic of the endstop.
        #define Z_MIN_ENDSTOP_INVERTING true // Set to true to invert the logic of the endstop.
      • DRV8825 Driver Types uncomment these and replace with DRV8825

          #define X_DRIVER_TYPE  DRV8825
          #define Y_DRIVER_TYPE  DRV8825
          #define Z_DRIVER_TYPE  DRV8825
          #define Z2_DRIVER_TYPE DRV8825
          #define E0_DRIVER_TYPE A4988
          #define E1_DRIVER_TYPE DRV8825
      • Double step count DRV8825 from 1/16 to 1/32 steps. This comes from the previous Marlin configuration which was #define DEFAULT_AXIS_STEPS_PER_UNIT { 80, 80, 400, 100 }. I've kept the extruder on a A4988 chip as the heat was building on too much on it. Calibrate to 0.84 volts.

          #define DEFAULT_AXIS_STEPS_PER_UNIT   { 160, 160, 800, 100 }
      • Invert X and Y directions. Invert extruder direction.

          #define INVERT_X_DIR true
          #define INVERT_Y_DIR true
          #define INVERT_E0_DIR true
      • Set Z travel limit. #define Z_MAX_POS 180

      • SD Card Support #define SDSUPPORT.

      • LCD Support for RepRap Discount Full Smart Controller #define REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER

  • DRV8825 calibration. The formula is VREF = Rated motor current / 2 . So a standard NEMA 17 motor is rated at 1.68 amps. Divided by 2 it's .84 volts. I burned out an extruder stepper following this. I dropped it to .6 volts. The steppers were less hot and no performance difference. Checkout

  • Replace display. The connectors are backwards for the standard RepRap Discount Full Smart Controller. Some Amazon reviews pointed this out.

  • Replace power supply. Found a 30A on Amazon for $20. The current 20A power supply is under powered. It's a known issue with these printers.

  • Replace Y bracket.

  • Easy access case for MKS Gen board

  • Filament sensor

  • Cover and mount for power supply

  • (Tested this but ended up reverting it) Manual LCD Bed leveling with #define MESH_BED_LEVELING, #define PROBE_MANUALLY and #define LCD_BED_LEVELING. uncommented LCD assisted bed leveling

  • Auto Bed Leveling using Z Probe Servo

    • Wiring

    • Marlin Configuration and Uncomment the following lines.

        #define NUM_SERVOS 3
        #define Z_PROBE_SERVO_NR 0
        #define Z_SERVO_ANGLES { 80, 0 } // This one is important on the servo arm deploy and retraction
        #define USE_ZMAX_PLUG  // I have an extra z max to use so this is used for the switch on the servo arm
        #define Z_CLEARANCE_BETWEEN_PROBES  10 // Z Clearance between probe points
        #define Z_CLEARANCE_MULTI_PROBE     10 // Z Clearance between multiple probes
        #define Z_PROBE_LOW_POINT          -10 // Farthest distance below the trigger-point to go before stopping
        #define Z_MIN_PROBE_PIN 19 // Pin 32 is the RAMPS default but we are using a MKS Gen 1.4 Board
      • M280 important! This controls the servo. Use this for testing: . Use the values gathered here to set Z_SERVO_ANGLES property.
        • Get servo 0 angle: M280 P0
        • Move servo 0 to a 90 degree angle: M280 P0 S90
        • Move servo 0 to a 0 degree angle: M280 P0 S0
      • Set marlin config of zprobe offset #define NOZZLE_TO_PROBE_OFFSET { -1, -40, -7.7 }
      • M420 get/set bed level state
      • M119 Endstop states
      • G29 start the auto bed leveling routine.

Click here for the full Marlin config difference.

Lessons Learned

  • Learned how to configure and almost build a 3d printer using an existing one.
  • Spent way more time than expected.