Initial Power and Motor Current Adjustment[edit | edit source]
Double and triple check the wiring to ensure that the power wiring polarity is correct; continuity checks should be made before applying power. Correct wiring before proceeding.
Plug the 12V power supply into a wall outlet and, while watching the electronics, plug the barrel connector into the socket on the printer. If you notice smoke and/or hear snapping, unplug the connector as quickly as possible. Properly wired electronics will cause all four blue LEDs on one side of the Beaglebone Black to light up for a short time and then one will flash to the rhythm of a heartbeat. No LEDs will light on the Melzi.
With the positive probe on the top of the pot and the negative probe touching the sd card holder, adjust the X, Y and X motor pots until 420 - 450mV is measured. The E-MOTOR should be set to 550V.]] With a small screwdriver and a voltmeter set for millivolt readings (400mV - 2V), adjust each of the small potentiometers on the Melzi for X, Y and Z to produce a potential of 420 - 450 mV measured between ground (the micro SD card holder can be used for ground) and the screwdriver used to adjust the potentiometer (see photo). The E-MOTOR should be set to 550mV. Two sets of hands simplifies the task. Be careful to not short anything on the Melzi with the screw driver or voltmeter probe.
Franklin[edit | edit source]
Franklin is software designed to work with all 3-D personal manufacturing robots like Athena. It is both server and firmware, exposing all settings and controls on a web page served by the host computer, which in the case of Athena, is the Beaglebone Green.
Initial Setup[edit | edit source]
- Connect an Ethernet cable from your computer to the port on the side of the printer.
- http://192.168.76.2:8000/admin and select "Open Link in New Tab". Note "admin" at the end of the address - Franklin has different pages allowing different levels of access to features.
- Right click on https://raw.githubusercontent.com/phidiasllc/athena/master/franklin-profiles/Athena.ini. Save the page (Save Link As...) to a logical and memorable location on your hard disk.
The firmware is now loaded, but the printer is uncalibrated and will not print properly. Complete setup as described, below.
Changing Values in Franklin[edit | edit source]
Values in Franklin are presented with an input text box for making changes. The currently active value is shown next to the box.
Those text boxes permit entry of a value which is then set by pressing the "Enter" key on the keyboard. Values can also be changed by selecting a text box (left click on it) followed by pressing cursor up and down movement keys on the key board:
- Page Up: increase value by 10
- Page Down: Decrease value by 10
- Up arrow: increase value by 1
- Down arrow: decrease value by 1
- Shift + Up arrow: increase value by 0.1
- Shift + Down arrow: decrease value by 0.1
Math can also be performed in the text boxes; entering +1.5 (note plus sign) will add 1.5 to the value, entering +-1.5 (note the plus and the minus signs) will subtract 1.5 from the value.
All values of the same type can be changed at once by making the change in the maroon bar below the values.
Pressing enter on an empty box is the same as entering 0. Setting a value to something that Franklin cannot understand as a number sets it to NaN ("Not a Number"). For some settings, this is useful; for example, a temperature control is switched off that way.
The special values Infinity and -Infinity can also be entered (note the capital I), which is useful for some settings.
Calibration[edit | edit source]
- Make sure the "Show Setup" checkbox is checked.
- Scroll to bottom of the page to show the printer control buttons.
- Click the "Home" button.
- Select the Z position text box (immediately below Z (mm)).
- Enter 0 in the Z position box (or leave it empty) and click Enter on the keyboard. The end effector should move down to approximately 10mm from the build platform.
- Place a piece of plain, white paper on the build platform under the hot end.
- In the Motor Settings area, select the text box in the maroon row under Switch pos (mm) and increase the values until the paper is slightly pinched between the hot end and the build platform while the Z position is 0 - the paper should be mobile when pulled and pushed, but resistance should be felt.
- Move to Z = 50mm (select Z pos text box, enter 50, press Enter).
- Select the Y position text box (immediately below Y (mm)) and enter a value of 100. Press Enter on the keyboard. The end effector should move near the vertex with the extruder drive mounted to it.
- Move to Z = 0mm.
- Select the text box for the w motor switch position and change its value using the up and down arrow keys (with Shift as required) until the resistance on moving the paper is about the same as it was in the middle of the build platform.
- Move to Z = 50mm (select the Z pos text box, enter 50 and press Enter). The end effector will move 50mm off the build platform.
- Select the Angle text box under the Delta section (it's a lone row in the middle of the position settings; not the setting at the bottom next to the target position.). Enter 240 and press Enter. The end effector should move to the U vertex (counterclockwise from extruder drive vertex when looking down). It does not move in a straight line (this is why the effector needed to be lifted before doing this).
- Move to Z = 0mm and adjust the u motor switch position until resistance is felt similar to that felt previously upon moving the paper.
- Move to Z = 50mm.
- Set the angle to 120 degrees (Delta section, Angle position = 120 followed by Enter).
- Move to Z = 0mm and adjust the v motor switch position until resistance is felt similar to that felt previously upon moving the paper.
- Home the printer.
- Set the angle to 0. (The end effector will not move.)
- Move to Z = 0mm and readjust all of the switch positions (in the Motor Settings area, select the text box in the maroon row, Switch Pos (mm) column) until the resistance upon moving the paper is the same as felt before. Take care only to use arrow keys or values starting with a + sign: the differences between the values must not change.
- Move to Y = 100mm.
- In the Delta area, adjust the radius of all motors at once (with the box in the maroon bar) until the resistance upon moving the paper is the same as felt before. (Decreasing the radius makes it more tight, increasing the radius makes it less tight.)
- Save the profile by clicking the Profile Save (as) button.
- Save a backup of the profile to your computer: right-click the "Export settings to file" link and select "Save link as...". Save the file using a logical name in a memorable loccation. The backup can be reloaded by clicking the "Choose File" button just above "Export settings to file" followed by clicking the "Import" button. The backup can also be used as a starting point for calibration of a second Athena.
Shutting Down[edit | edit source]
Because the Beaglebone is a computer, it should be shut down in a controlled way. There is a web interface for doing this at http://192.168.76.2/cgi-bin/shutdown . When clicking the button on that page, the machine will shut down. It normally responds with an error that the host is unreachable, that means it shut down before the response was sent, so that means it worked.
To power it back up, the power must be disconnected, and plugged back in.
The Athena does not use much power while it is idle, so it is not required to turn it off very often. This means it is easy to forget the shutdown link, so it is a good idea to bookmark it along with the Franklin link given below.