Template:RepRapPro maintenance

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Uploading new firmware

The firmware is the computer program that resides in the microcontroller chip on the controller printed circuit board.

Required software

Downloading from Github

Most of the data you need for RepRapPro hardware and software is on Github. Navigate to the appropriate page.

Then download your software with the button on the left to get it as a .ZIP file:

Reprappro-huxley-get-github-zip.png

Arduino and Sanguino

Get the Arduino IDE from the Arduino website here. It's probably best to use Version 0023 until Arduino 1.0 settles down.

Add the Sanguino files to your Arduino hardware folder. See the README file in that Github repository for instructions.

Git repository

Firmware source code is stored in the RepRapPro git repository. Download the zip file as shown above (the little picture of a cloud with a down-arrow labelled ZIP) and then extract the main folder to your drive. Copy this into your ~/sketchbook folder to make it visible within the Arduino IDE. The Arduino software is much easier to use when it knows where you keep the RepRapPro files, so use File/Preferences to set your preferred location.

Uploading

In order to upload firmware into the controller you need to make sure that the board's reset jumper is installed:

Reprappro-huxley-rest-jumpers.jpg

You can take it off when you have finished uploading. Hang it on one of the pins so it doesn't get lost.


Reprappro-huxley-arduino-upload.png

Launch the Arduino IDE, and use the File | Sketchbook menu to open one of the two main firmware projects (depending on your electronics board): Sprinter_Melzi or Sprinter_Sanguinololu. (The third option, the Marlin_Sanguinololu project, will only work if your board has the ATmega1284P chip since it requires more memory.)

Select the Sanguino board from the Tools | Board menu. Check your processor type (look at the number on the big chip on the controller board). You will either need to select "Sanguino W/ATmega644P" or "Sanguino W/ATmega1284p 16 mhz", as appropriate. (If you can't see the Sanguino boards you will need to check that you have downloaded the right files and moved them to the correct folder - see above).

Ensure the serial port is ticked from the Tools | Serial port menu (the RepRap controller board must be physically connected to your computer with the USB cable at this stage).

Select the tab for the file Configuration.h. At the top are the following lines:

// Uncomment ONE of the next three lines - the one for your RepRap machine
//#define REPRAPPRO_HUXLEY
//#define REPRAPPRO_MENDEL
//#define REPRAPPRO_WALLACE

// Uncomment ONE of the next two lines - the one for your master controller electronics
//#define REPRAPPRO_MELZI
//#define REPRAPPRO_SANGUINOLOLU

// Uncomment ONE of the next two lines - the one for the series resistors on your controller
//#define SERIAL_R 4700
//#define SERIAL_R 10000

// Uncomment the next line if your machine has more than one extruder
//#define REPRAPPRO_MULTIMATERIALS

Uncomment (i.e. remove the two // characters) from the line corresponding to your machine and your control electronics.

If you have a Sanguinololu controller uncomment the
#define SERIAL_R 4700
line.

If you have a Melzi controller you need to look at the resistor value on the printed circuit board:

Reprappro-mendel-melzi-resistor.jpg

The screw connector at the top of the picture is the one for the hot-end thermistor. Just behind it you can see a small black resistor with 103 written on it. That is a 10K resistor (the last digit is the number of zeros). If your board has that, uncomment the
#define SERIAL_R 10000
line. If it has one labelled 472, uncomment the
#define SERIAL_R 4700
line.

If you have a multi-extruder or mixer-extruder Mendel uncomment the

//#define REPRAPPRO_MULTIMATERIALS

line.


Further on you will see the following section:

// X, Y, Z, E steps per mm
#define DEFAULT_AXIS_STEPS_PER_UNIT   {91.4286, 91.4286, 4000, 875} 

These four values allow you to store accurate settings for your printer. Once you have calibrated your printer, particularly the fourth value for Extruder steps, you can edit this line.

To upload your firmware, click the Play button (the first button) to verify that the code compiles correctly, then click Upload (the sixth button) to send the firmware to your processor.


Dismantling the hot end

With care you can completely to dismantle the hot end:

  1. Cut the PLA filament so that you have about 300 mm sticking out of the feed side of the drive.
  2. Loosen the spring screws on the drive (or remove them) so that the filament is not being gripped at all.
  3. Pull the tongue out of the drive to release the brass coupling. Pull the filament through the drive so the PTFE tube and filament are free.
  4. Run the hot end up to temperature, and wait for about 30 seconds.
  5. Push the filament through by hand so that it extrudes slowly. Push about 100mm of filament through to get fresh material right through the hot bit.
  6. Turn the heat off, and watch the temperature as it cools. Clean any extruded filament away from the end of the nozzle.
  7. When it gets down to 100 C, pull the free end of the filament gently but firmly. At that temperature the plastic should be soft enough to come out of the heater assembly, stretching a bit. But it should be coherent enough to hold together; it should all come out, right down to the nozzle, leaving the filament path completely empty.
  8. Disconnect the power and wait for everything to get to room temperature.
  9. Disconnect the hot end wires from the controller board, and slacken the two screws that hold the hot end to the X carriage. Take the hot end off the machine.
  10. Cut the cable ties on the fan heatsink that retain the wires.
  11. Unscrew the fan and heatsink and set them aside.
  12. Unscrew the PTFE cone at the bottom of the nozzle, and set that aside. For the next three steps, take care not to damage the wiring as you unscrew things. Take your time and hold the wires out of the way.
  13. With long-nosed pliers unscrew the brass end of the PTFE tube from the long block. Set the PTFE tube aside.
  14. Unscrew the long block from the short double-threaded stainless steel tube. Set the long block aside.
  15. Retrieve the short length of PTFE from within the counterbored recess in the stainless tube. Set it aside.
  16. Carefully remove the crimps from one end of the thermistor wire and the heater resistor wires.
  17. Pull the heater resistor and the thermistor out from the other end of the aluminium block.
  18. Gently hold the aluminium block in a vice, and use an adjustable spanner on the flats of the brass nozzle to unscrew that.
  19. Unscrew the stainless steel tube, taking care not to damage its threads if you have to grip it.
  20. Clean all residues of PTFE tape from the components.

To reassemble the hot end, follow the instructions on the hot end assembly page for Huxley here and for Mendel here.