Step 1: Pre-anything mechanical checks
- Make sure that everything you put together in the mechanical assembly is securely fastened and levelled in the correct place.
- Check that your heated printbed is mounted securely and levelled on the aluminium Y-carriage, using the 4 bolts, 4 nuts and 4 springs.
- Check that the belt sprockets are very securely fastened to the X- and Y-motors (this is something I cannot stress enough - if the grub screws loosen mid-print it will seriously damage your print) and that the belts are tight enough but not too tight. Test the tightness with your finger, it shouldn't deflect more than about 5mm when pressing down on it with light force. (This value was heuristically chosen but should give you an adequate idea).
- Test the quality of movement of all axes by moving the carriages from end to end. Adjust axis alignment, oil bearings, fasten nuts and do anything else to get a smooth, unhindered movement in all axes. To get movement in the Z-direction, just turn both threaded shafts connected to the Z-motors in the same direction.
- Do bed-levelling by positioning the hotend nozzle a few millimeters above the printbed and adjusting all relevant axes in order the move the nozzle over the entire area of the printbed. Adjust the bed-level by fastening or loosening the bolts at its four corners.
- Make sure the extruder hole aligns perfectly where it meets up with the hole in the top of the hotend so that filament can fit nicely through from top to bottom. Test this by pushing a piece of filament in from the top (pushing down on the extruder spring clamp to allow the filament to go through) and letting it go almost to the bottom of the hotend where the nozzle starts getting narrow.
Step 2: Pre-anything electronic checks
- Check that your wiring is clean, neat and out of the way of any moving parts. I've done this with my wiring on the printer itself (small cable ties are awesome for this job), but the wires lying next to my printer (those connected to the controller board) are a totally different case. I'm still planning on printing an enclosure for the excess wires and the controller board.
- Make sure that the stepper motor wire connectors are securely connected to the motor ports.
- Make sure that the two Z-motors are wired in parallel. The separate groups of wire coming from both motor connectors should be joined so that a single group goes to the controller side where a single stepper motor driver controls both motors. This should be more evident once I supply a wiring diagram (or if I do?).
- Be sure that every important electrical component on the printer is connected to the relevant ports on the Gen 7 control board: the 5 stepper motors to the 4 stepper motor driver connectors, the heated printbed and its thermistor to their ports, the hotend and its thermistor to their ports, the three limit switches to their ports, and the 12V and GND connections from the power supply to the power input ports. The 12V hotend fan can also be wired directly to these power input ports as it should always be on during all prints in order to help dissipate heat from the hotend.
- Turn the pots on your stepper motor drivers all the way down. On my Gen 7 board I have four Polulu A4988 drivers and on them "all the way down" means all the way counter clockwise.
- Do not connect your USB cable yet, and also don't switch on the power supply yet.
The basic set of software installs you'll need in order to have everything up and running is as follows:
- The MCP2200 USB to Serial driver to let your PC communicate with the Gen 7 controller board (on Mac OS X Yosemite this is capability is pre-existing and no drivers are needed; I am unsure if this is true for other Mac software versions, though).
- Slic3r, which converts STL files into gcode which the printer can interpret.
- Printrun/Pronterface (on Mac it is called Printrun-Mac) to enable communication between your PC/Mac and the printer.
Downloads for these software packages are provided at this OpenHardware link.
Step 4: Hooking up your printer and making stuff move
Once the necessary software is installed, it is time for the long awaited initial unveiling. At this point it's probably a very good idea not to let your excitement get the better of your logical thinking, as this might lead to some random failures and disappointment.
Step 4: Hooking up your printer and making stuff move
Once the necessary software is installed, it is time for the long awaited initial unveiling. At this point it's probably a very good idea not to let your excitement get the better of your logical thinking, as this might lead to some random failures and disappointment.
- Connect the Gen 7 printer controller board to USB port on your PC/Mac. A red LED on the Gen 7 board should start flashing.
- Open Printrun/Pronterface, making sure that the correct COM port is selected for the printer and that the baud rate is set at 115200.
- Turn on the printer's power supply. Remember, your stepper motor motor drivers are turned all the way down, so nothing should make loud noises or anything (if they do, it's probably a good idea to leave everything and run). I suggest double checking the stepper motors one by one before switching everything on at once - just plug in the stepper motor you are testing, apply power and see what happens.
- Connect to the printer from Pronterface. If everything functions as it should, you will hear a fairly load clicking sound coming from the stepper motors.
- Tune your stepper motor drivers, using Pronterface, to allow the motors to receive the appropriate amount of current for printing purposes. Use this post as a guideline for tuning the drivers.
- A very important step: calibrate your extruder! These posts give ample information about how to go about this. RichRap's blog is a vast treasure of valuable 3D printing information, I recommend reading everything he has ever written:
- OpenHardware extruder calibration
- RichRap's Slic3r is Nicer Part 1 (read parts 2 and 3 as well!)
- The RepRap wiki on calibration
- Remember to check that your hotend fan starts blowing immediately when the printer is switched on. This way, when the hotend temperature is set from Pronterface, your hotend heat exchanger will stay cooled and the temperature won't creep up your filament and cause problems during extrusion (this happened to me and I had to learn the hard way).
So that's about it in terms of pre-print checks (well, that and all the millions of other things I forgot to mention). At this stage we are ready for the first print, which is what my next blog post will cover. I'm sorry that I didn't post any pretty pictures or videos and that it's all just a bunch of words. I promise to correct that with my next post. For now, here is a potato.
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| Source: http://www.moffatcan.org/shop/?product=potatoes-2 |
Peace.
S
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