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Bukobot Flight Check

What to do before starting to print for the first time.

FIXME - This page may need a little updating.

#1 Check Power

  • Check that the power supply input switch is set to the right input voltage for your country (110 for the US, factory setting is 220).
  • Check power wire polarity, Power supply in (AC), Power supply out (DC), and Controller input

#2 Plug in Power and USB

Check Printer Settings, and select your printer from the drop down options (Do not select “Virtual Printer”, it does nothing)

See Repetier Documention for Details

* MAC:  "usbserial-XXXXXXXX" 
* Windows: COM(Number)
* Linx: USB(Number)

If your printer is plugged into your USB port and you do not see one of these options, you probably haven't installed the FTDI driver. Find the correct driver for your system on this page:

  • Make sure baud rate is set to 250000 (115200 if you reinstalled the firmware with SERIAL_COMPATIBILITY enabled)
  • If you have a dual extruder machine, switch to the “behavior” tab in “Printer Settings” and set number of extruders to 2.
  • Close printer settings and connect to printer.

#3 Check Motors

Switch to “Print Panel” (“Manual Control” in newer windows versions) and check motor connections and directions (if any are wrong, click “Stop motor” or “Turn motor off” before plugging/unplugging them, fix wrong direction by turning the connector over) center the X and Y, and make sure Z has room to move in both directions

  • Click the positive 10 for the X axis. Extruder should move toward the right.
  • Click the positive 10 for the Y axis. Platform should move toward the front.
  • Click the positive 10 for the Z axis. Extruder should move up should move up.
  • Type M302 into the gcode box above the jog controls and send to disable cold extrusion prevention (no filament should be loaded).
  • Scroll to the extruder settings below the jog controls.
  • Click extrude, and look at the drive gear for extruder 1 from above.

It should be turning toward the filament channel (clockwise for a left extruder, counter-clockwise for a right extruder, if you only have one, it's probably configured as a right extruder).

While you are doing this, make sure that your drive gear is aligned properly. The lowest point in the grooves should line up with the hole for the heater barrel. If it isn't, turn the extruder in 1mm increments until the setscrew is pointed in a convenient direction to loosen it, slide the drive gear until it is properly aligned, and re-tighten it.

If you have a dual extruder:

  • The right extruder should be the one that is turning
  • Select extruder 2 and repeat, checking the left extruder.

#4 Check Your Endstops

Locate the blue reset button near the USB connector and be ready to press it if an endstop does not function. Click the “Stop Motor” button in Repetier host to make sure the motors are not engaged, then manually push the extruder to the right end. Click the “Home X” button in Repetier host, then tap the X endstop switch. The extruder should begin moving left and stop when you hit the button. When it stops, it will reverse a few millimeters, then move to the left again more slowly for a few more millimeters. If the extruder does not stop when you tap the the endstop switch, check your endstop wiring. You may have the X endstop plugged into the wrong endstop port. If it works, click “Home X” again to ensure that the X carriage properly touches the endstop when it gets to the left end.

Repeat this procedure with the Y axis, starting by moving the platform manually to the front.

Click the “Stop Motor” button in Repetier host again and make sure that your Z axis is at least a few inches above its endstop so that you have time to react if the axis does not stop, turning both screws together by hand if necessary. Unlike the other axes, Z has enough mechanical advantage to potentially break things if it does not stop, but is also moves much more slowly.

Click “Home Z”, then test the Z endstop again as above. Be sure to keep your finger on the reset button in case the endstop does not function.

Lift your Z axis to 100mm using the jog controls.

#5 Check your heaters

Switch to temperature curve view.

Make sure you are set to extruder 1, set temperature to 60 and turn it on.

Check to see that the extruder 1 temperature (thin red line) starts moving up (it should be pretty fast)

If it doesn't start to rise after a few seconds, turn the heat off immediately.

If you have a dual extruder and the temperature monitor does not show the extruder heating, try switching to extruder 2. If the line jumps up when you do this, you have the wrong thermistor connected to each extruder heater. Fix this by switching your extruder 1 and extruder 2 thermistor connections, then start over the “Check your heaters” procedure.

If that was not the problem, check the wiring for your extruder heater and thermistor.

  • Check the screw terminals on the controller board where the heater connects.
  • Check the screw terminals on the carriage where the thermistor connects, and the plug where it connects to the electronics.

If both of these appear to be ok, unplug the machine and disconnect the heater and thermistor wires. Check the resistance of the heater and thermistor with a multimeter.

The heater should read 3.3 ohms. Many multimeters will have trouble measuring accurately at this low resistance, so don't worry if it measures a little off.

The most likely failure mode is infinite resistance (open circuit), which indicates a damaged or defective heater that needs to be replaced, or that you are checking the wrong pair of wires (for example, one wire from one heater and one wire from the other).

  • The thermistor should read roughly 100 Kohms. The actual value will vary with temperature.

The most likely failure mode is infinite resistance (open circuit), which indicates that a wire is not connected or broken.

The second most likely failure mode is no resistance (short circuit), indicating that the two thermistor wires are connected to each other somewhere, bypassing the thermistor. A multimeter with an audible continuity test mode is best for tracking down either of these problems.

  • Turn your extruder off.

If your first extruder heats properly and you have two, check that the temperature reading is below 60 and that you haven't heated the other extruder, then check each of the heater blocks to see which is actually warm. You can use a thermocouple probe or an infrared thermometer for this if you have one, otherwise use your finger after CAREFULLY ensuring that neither extruder has been heated above 60C, otherwise you may burn yourself.

The right block should be warm, and the left should be cool. If the left block is the warm one, switch both the extruder thermistor connectors and the extruder heater wires on your controller board, then start over the “Check your heaters” procedure.

Switch to Extruder 2 and check it the same way.

  • Set platform temperature to 60 and turn it on.
  • The LED indicator on the platform should turn on.
  • Check to see that the platform temperature (thin blue line) starts moving up (it may take a few seconds to start)

Turn the platform off.

You are now ready for a test extrusion.

Heat your extruder to 210C if you are going to test with PLA, or 230 if you are going to test with ABS. Set the extruder speed to 100mm/min. Straighten the end of your filament and push it down to the top of the barrel as far as it will go, then flip the handle on the idler mechanism up to lock it against the drive gear.

Set the extrude length to 10mm and press extrude when the temperature curve display in Repetier Host indicates that it has reached the target temperature. If you hear your extruder clicking when you try this, release the idler and try inserting the filament again. It will be easier to get it started if you sharpen the tip of the filament a bit.

Click extrude a few more times until plastic starts coming out of the nozzle. If your machine was pre-assembled, there may already be PLA in the nozzle that may not match the color of what you put in. If this happens, just continue extruding until the old plastic is flushed out and the plastic coming out is the same color as what's going in. Some people like to save their printer's first test extrusion, or “noodle”, as a keepsake.

Your machine is configured to automatically extrude a few millimeters of filament every 30 seconds if you leave it idling while hot. This is to prevent plastic from sitting hot in the nozzle too long and burning or oozing out and leaving the nozzle un-primed. For the next step, you want your nozzle hot so that the metal is fully expanded, but you don't want any plastic coming out, so retract the plastic 10mm. Square and tram your machine.

The term “tram” means to make your platform parallel to the X/Y plane of the machine. This does not need to be level (perpendicular to gravity), and in fact your machine should be able to print upside-down or in zero gravity.

First, you must square your machine. A machinist's square is best, but a small carpenter's square will also work. Start by checking the squareness of the joint where your Y axis connects to the frame. This will square your machine on the X/Y plane. The frame is designed to use the right angles of the aluminum extrusions to be self-squaring on the Y/Z plane, so you just need to square the X/Z plane. To do this, move your Z axis up or down until you can stand your square on the bottom frame beam and the X axis bars are just above it. Click “Stop Motor” in Repetier Host to disengage your Z motors, then turn them by hand until the bar just touches your standing square. Move the square to the other side and turn the motor on that side while holding the other still (when one Z motor turns, the other will try to turn with it) until it just touches. Repeat this process, moving from one side to the other until no adjustment is needed on either side for the rod to just touch the square.

Tighten your three platform mounting adjustment nuts until the springs are fully compressed, then home your Z axis. Click “Stop Motor” to make sure your X and Y motors are disengaged, then move the extruder and platform by hand until the nozzle is over the glass nearest one of the adjustment screws, and loosen that nut until the nozzle just touches. Your nozzle should still be hot at this point, because the barrel will get slightly longer due to thermal expansion when it heats up. If plastic has started extruding out of the nozzle, clean it off with tweezers and retract the filament 10mm again.

To check the height, slip a piece of paper under the nozzle to use as a feeler gauge (post-it notes work particularly well for this if you put the sticky side up and stick your fingers to it). The nozzle should just barely press the paper against the platform and resist when you try to move the paper around, but should not grip it firmly.

Move the extruder and platform to one of the other screws and repeat this procedure until all three have been adjusted.

Open the ”bukobot tram 200mm.gcode” file and click run (If you have a dual extruder Bukobot shipped prior to the beginning of 2014, select extruder 2 for now, as this code assumes that your nozzle is touching the front left corner at zero). This will move the nozzle to the each of the screw positions and touch the platform, then pause to wait for you to adjust the screw if necessary. Once it has touched each position twice, it will print a border around the platform. Watch it print this to ensure that the thickness of the lines being put down is consistent. If the lines do not touch the previous line, that part of the platform edge is too low and needs to be adjusted up, if the lines are too wide and flat or the nozzle gets close enough to the platform to block the nozzle entirely and no plastic comes out, adjust that part down. If it's a corner without a screw, adjust the screw on the opposite corner in the opposite direction. If your platform is not correctly adjusted by the time it finishes printing the outlines, cancel the print and start again, otherwise click continue and the printer will begin a test print.

If you have a single extruder, you're done!
If you have a dual extruder:

You'll need to measure the offset of the nozzles to prepare for dual extrusion. To do this, make sure your extruders are loaded with two different colors of PLA and run ”combined offset test 2.1.gcode”. This will print a test pattern to allow you to calibrate the extruder offset. Find the line in the vertical and horizontal test that match up best and look up the corresponding number in the table at the beginning of that file. Insert these numbers into the toolhead offset for your left extruder in Slic3r. For more detail on this process, and for a brief tutorial on how to use a duo, download pdf file here.

You're done and ready to start printing in 3D!

flight-check.txt · Last modified: 2014/02/12 18:57 by whosawhatsis