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MY4777 Athena Printer Modifications by Cikaub

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MOST Delta filament as guide.JPG This page was part of an MTU course MSE4777 OA and MSE4777 OB/MSE5777/EE4777/EE5777: Open-source 3-D printing

Please leave comments using the discussion tab. The course runs in the Fall semester. It is not open edit.



Athena Heated Print Bed[edit]

This page outlines one possible method to expand the Athena printer with a heated bed that still allows for the addition of extuder fans and secondary hotends.

Project Created by: User:Cikaub


Design[edit]

Athena printer was equipted with a 12v 220mm diameter heated bed to replace the basic tempered glass surface. As it is desirable to have a fan mounted on the hotend to assist in printer slow freezing plastics like PLA the mod also entails the replacement of printer controller and power supply. The beaglebone and melzi controller are replaced with an arduino mega compatible micro controller with RAMPS 1.4 shield so that secondary hotends and fans may still be added to the printer.

Features[edit]

  • Expanded I/O for second hot end and extruder controls built-in
  • Fully integrated controller allows for SD card printing without the need for a tethered PC
  • Hotend fan and heated bed allows for fast and effective printing of ABS and PLA
  • Socketed stepper controllers allows for easy and economical replacement without the need to rework PCB as with melzi

Construction and BOM[edit]

Bill of Materials[edit]

BOM
Item Quantity Price
220mm diameter heated bed- 12v, 200W 1 [ali_express $35.08]
220mm diameter tempered glass printing surface 1 $11.57
Arduino Mega or compatible controller 1 $10.98
RAMPS 1.4 Shield or compatible 1 $14.80
RAMPS 1.4 LCD screen unit with SD card slot 1 $20.00
Pololu A4988 or compatible stepper motor driver 4+ $0
12v heating element for existing hotend 1 $9.40
female breakaway pin-headers 1/4" pitch 10+ $1.17
Power Supply with 12V rail 1 N/A salvaged ($0.00)
Threaded Standoffs, brass or steel 4 $3.80
Total Cost $106.80

Construction[edit]

Tools Needed
Soldering Iron
Square drive screw driver
Wire strippers and cutters
Cable ties
Bubble Level
Misc screw drivers and pliers
  1. placeholder steps
  2. Step 1: Teardown

Remove the Melzi unit and the I/O breakout, disconnect all the stepper drivers and note what wire pairs are what coils. Remove the existing print surface and remove the printed hold downs completely. Remove the existing 24v heating element front the hotend and clip it off the effector wiring harness.

  1. Step 2: Microcontroller Prep

Connect your the arduino mega to you PC and prepare it, for preparing an arduino compatible micro controller see https://www.arduino.cc/ for more info. You will then need to flash your arduino with a printer firmware of which Repetier is recommended. Repetier's website has an guided configuration tool which allows you to pre-configure your firmware with the specific measurements for a the Athena, please see https://www.repetier.com/documentation/repetier-firmware/ for detailed instructions.

  1. Step 3: Bed installation

Screw your new standoffs into the surface of the bed support, then slide in your heated bed assembly with the heated mat on the bottom and the glass on the top. Use a bubble level to ensure it flat in all directions and raise or lower your standoffs as needed.

  1. Step 4:Wiring

Disconnect your now configured microcontroller from your PC and attach the RAMPS shield, install your stepper drivers in appropriate sockets (X,Y,Z motor order do not matter for a delta design like Athena. Using the pinheads create connectors for all 4 of your stepper motors making sure that the coil pairs are adjacent in the connector. Install your new 12V heating element into your hotend and splice it back into the effector wiring harness. Attach the wires for the bed, hotend, and power supply to their terminals. Connect the screen/SD card assembly connectors to their appropriate sockets ensuring the keys line up in the connector sockets.

  1. Step 5: Cleanup and Configuration

Reconnect your PC to the microcotroller and connect to it with the Repetier-Host program, use the EEPROM option to tune the print radius and z0 of your printer. Confirm all steppers are moving and in the expected directions, if not either reverse their connectors or tune the current limiting adjustment on the stepper drivers. Ensure the bed is heating correctly and that the thermistor is reading appropriate values. Find a nice place to mount your new controller unit, ensuring good airflow over the top to cool your stepper drivers.



Common Problems[edit]

  • 1. My steppers wont move!

Make sure your connectors are wired appropriately and that your stepper controller is working normally (IE not overheating or has its current adjustment turned all the way down)

  • 2. My hotend heats up super slow!

Make sure your using a heating element rated for 12V operation, using the stock 24V element will result in very slow heating of the extruder.

  • 3. MY LCD screen unit is blank!

Swap connectors on the RAMPS board or invert them depending.