Makerbot Replicator 2 Replacing Electronics #1

Hi there,

I’m working at the FabLab Darmstadt and we have several 3D Printers. One of them is the Makerbot Replicator 2. This 3D Printer did very good prints until the display failed. An unkown IC on the display pcb was just blown. I then uploaded a sailfish firmware for the Mighty Board with no display, tried to move one of the motors… Bang.. Magic smoke.  Tried another axis, same phenomenon.

I thought this might be a good point to convert the electronics to something open source. I wanted to have more control over the printer and be able to control it remotely via OctoPrint.

My hardware goals were the following:

  • Arduino Mega 2560 with RAMPS Board
  • DRV8825 with 1/32th stepping
  • Display
  • Raspberry PI 3 for running Octoprint
  • Multiple external USB ports to run multiple 3D printers with just one Raspberry PI 3 (I am going to write an extra blog post about this)
  • Reusing the original PSU

So now let’s have a look at the changes I’ve done to the Makerbot.

First thing I’ve done was a new custom backplate. It was  lasercut using our 50W CO2 Laser. The Makerbot now has an Ethernet Port, Powerswitch and Speakon for Power. I chose Speakon, because the connectors are locked and you can’t reverse polarity, although it’s a bit bulky (I know it’s not good to choose connectors which are meant for other purposes, I just hope no one is going to plug this one into a speaker). I disliked the original connector, because you could reverse polarity with just a little bit of force and even the design didn’t use a symmetrie of the connector (yeah because the PSU was off the shelf and so the pinout is fixed).

Next thing was to mount all pcbs. I just drilled some holes and used a lot of distance sleeves. In another HOWTO on thingiverse someone just hotglued all boards onto the metal plate, this is what I wasn’t going to do. To get the power up and running I am using a DC-DC converter to feed 5V to the PI 3. Also it’s very important to remove a diode on the RAMPS board which forwards the motor voltage to the Arduino’s voltage regulator. Because the Makerbot is running on 24V, I had to do this. The voltage regulator cannot handle 24V (only up to 20V). The Arduino is then powered via USB from the PI 3.

In case of maintenance I wanted something to prevent reversing the direction of the motors, so I added a lot of PSK connectors to the RAMPS board.

Here in the back you can see 3 USB ports for additional 3D Printers (or other USB stuff). The red button in the front is the reset button for the MakerBot’s Arduino, with the green button you can activate the access to OctoPrint. This was needed as a security feature, so no one with access to the Network can control the printer without accessing it physically.

You can find my Configuration.h for MARLIN on Github (this file is only useful for steps per mm, because I am not using the stock Makerbot Hotend):

https://github.com/vimtut0r/Marlin/blob/RC/Marlin/Configuration.h

Results:

Here you can see the result of the Makerbot Replicator 2 (white) compared to a print from a 3Dator (https://www.3dator.com) (orange).

Future goals:

  • Add controller for LEDs
  • Add camera
  • Heated bed (maybe automated bed?)
  • Filament sensor

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