Assembling your ALUNAR 3D printer

The instructions for assembling your 3D printer are in video format. I’ve added notes here to help you interpret and check the video. Be sure to follow these directions very carefully. Also, be sure to watch each segment once before beginning that section of the assembly process. Lastly, you may find it useful to keep a larger picture of the printer open to compare to the video.

A. Assembling the X/Y frame (0:00-0:22)

  1. Before you assemble anything, watch the first 15 seconds of video. At 0:11 note that the aluminum extrusion for the frame you are making are all the same length, but two have a single hole and two have no hole. Be sure to line up your extrusion bars and find exactly those four (each is 37.5cm long). Also note that the bars with the holes go inside the other bars, and that the holes have room for an inset screw on one side but not the other (make sure they are rotated so that is on the same side for both bars). and follow this exactly.
  2. Be sure the aluminum extrusion bars are rotated correctly to match the video and find the corner pieces to attach the bars. Be sure to find an appropriate hex wrench so you can tighten them.
  3. Check that your corners make right angles once assembled. Now turn your XY frame so that the inset sized holes in the extrusion crosspieces face up, and the small holes face down.
  4. Insert the right angle pieces and tighten the set screws that should already be placed in them.
  5. Attach the corner pieces to top of the XY frame. The corner pieces at 00:20 are laser cut acrylic. You’ll find them in a box of spare parts at the bottom of your printer box. You’ll need the T-nuts and the M4 8mm bolts for this, be sure to take the right length bolts from your 8mm & 12mm bolt bag. Also be sure to orient the bolts so that the bolt heads are inset and to orient the nuts so that the rough lines point in (toward the extrusion bar). Be sure to thoroughly tighten every bolt.

B. Assembly of Z Axis frame (0:22-1:03)

  1. Flip the XY frame over. Now the acrylic pieces and the inset holes are down. Then attach the two 44cm long Z extrusion pieces to the frame using two M5 25mm bolts as shown at 00:24 of the video.
  2. Stabilize the Z axis as shown at 00:32, using the same M4 8mm bolts and T-nuts you used earlier along with the right angle supports. Not shown in the image, but critical is to make use of the washers here, otherwise your M4 8mm bolts might slip right through the holes in the right angle supports.
  3. 0:50 Attach the brackets for the motors using M4 8mm bolts and T-nuts. Position each one so that it is centered on the z-axis, and they rest against the floor when you place the x-y frame on the floor.
  4. Next attach the z-axis motors, using the M3 6mm screws. The right motors have identical motor shaft attachments, which resemble those in the video (don’t confuse them with the extruder motor or the x/y axis motors). Note that the cords attachments are not visible in the video because they are facing away from you (toward the shorter side of the x/y frame). Don’t overtighten the screws holding the motors as they will strip easily. 

C. Assembly of print bed frame (1:03-1:18)

  1. Find the 41.5cm long extrusion. As can be seen at 1:04, this is placed across the x/y frame, and should be long enough to sit on top of it.
  2. Find the acrylic laser cut bed piece with the words X3 cut into it.
  3. Find the parts visible in the video at 1:06. These include four plastic pillars (found in the bag with the springs), four M5 nuts, four M5 35mm bolts, and 4 bearings. Assemble them as shown in the video. Make sure you tighten them properly (this will require a wrench to hold the bolts as you tighten the nuts).
  4. Slide the acrylic bed piece onto the crossbar, so that the bearings sit in the indentations in the extrusion. It should roll smoothly along the crossbar.
  5. Use the right angle supports (with T-nuts, M4 8mm bolts, and washers) to secure the crossbar to the XY frame. Make sure to center it. Important: If the printer front is facing you (i.e. the Z axis is more than halfway toward the back of the XY frame), the right angle supports go on the right side of the crossbar.

D. Attach the Y axis drive and timing belt (1:18-1:40)

  1. Add the y axis drive motor (1:19). The pointy extension of the laser cut acrylic should point away from the motor power supply. Use the M3 6mm bolts to attach the acrylic to the motor (note that the acrylic is non-symmetric, make sure the bolt heads are inset in it. Also, the set screws on the drive pulley on my motor were loose, so it came off. If that happens to you, just put it back on and tighten slightly (you may want to adjust the position of this later. Be sure one of the two set screws lines up with the flat side of the motor shaft when you do this).
  2. Add the y axis end stop (1:22). You should at this point compare all three end stops and pick the one with the shortest wire, as you will need a longer wire for the x axis end stop. Use the silver-colored M2 10mm bolts and M2 nuts found in the bag with the springs. Be sure to orient the end stop as shown in the video, on the same side of the acrylic as the motor, and with the metal switch opening up and out.
  3. Attach the entire contraption to the crossbar using M4 8mm bolts and T-nuts. You will have to squeeze the bolts in between the wires coming off of the end-stop. Be gentle. Also make sure you are happy with where the wires going are as you tighten things down.
  4. Find the piece of acrylic shown in 1:28. Do not confuse it with the very similar piece in shape that has more than 3 holes in it. Attach it to the crossbar using M4 8mm bolts and T-nuts, so that the extra hole and rounded end stick out as shown at 1:28.
  5. Find the bearing, which is pre-assembled and in the bottom half of your printer box. You will need to unscrew the bolt, be careful to keep everything in the right order when you do so. Attach it as shown at 1:28/9.
  6. Find the timing belt. In the same bag you will find two black zip ties. The timing belt will run along the bottom of the crossbar, in the divet in its center. You’ll need to insert it between the crossbar and the xy frame. This is a good time to also adjust the position of the drive pully on the Y moter shaft, so that the timing belt lines up with the divet on that end. You will also need to insert the ends of the timing belt into the smily face cutouts on the print bed piece (with the X3 on it). With a little dugging you can slide it over until it lines up with the divet there too.
  7. Tighten and secure the timing belt. Making it tight enough is important for future functioning. Tightening can be done by moving the acrylic piece with the bearing attached (but you have to make sure there is room for it to move in the tighter direction. Assume your belt will loosen and leave your self some extra room for the future).

E. Extruder head carriage assembly (1:40-2:31)

  1. Find the triangular acrylic piece and motor mount shown at 1:42, along with 4 M4 12mm bolts and 4 M4 nuts. Assemble as shown, with the motor mount extending from the long side of the triangular acrylic piece.
  2. Find the triangular acrylic piece (identical to step E1) and 3D printed plastic piece shown at 1:45, along with 2 M4 12mm bolts and 2 M4 nuts. Assemble as shown, noting the orientation and the location of the bolts in the middlemost holes of the acrylic. Do your best to make sure the top of 3D printed piece makes a right angle with the long end of the acrylic piece.
  3. Find the base for the z-axis threaded rod, and the bolts and nuts to secure it. They should all be in the same bag that the 3D printed piece was in. Assemble them as shown at 1:48.
  4. Attach the two pieces together as shown at 1:50. You will need six plastic pillars, and three bearings, M5 45mm bolts and M5 nuts. As usual, check orientation before you finish assembling and after.
  5. Repeat step 1, noting the 90 degree change in relative orientation of the acrylic piece and motor mount (see 1:57).
  6. Repeat step 2, noting the mirror image orientation (see 2:00).
  7. Repeat step 3 (2:02).
  8. Repeat step 4 (2:07). Pay attention to relative orientation.
  9. Place on the Z-axis frame as shown at 2:12. Pat yourself on the back :).
  10. You’re not done yet! Attach the extruder crossbar (40cm long) using M4 12mm bolts and T-nuts as shown at 2:22. It should be approximately centered.
  11. Gently screw in the z-axis threaded rods (2:26). I had to free mine from their saran wrap with a box cutter. Once they are positioned, loosen the thumb screws to move the shaft coupler, which is used to attach the threaded rods to the motors.
  12. Add the top bar. Use the two remaining M5 25mm bolts to attach it, and make sure you rotate it so that the bolt heads can be inset in the crossbar divet.
  13. Now pat yourself on the back again!

E. Attach the extruder head and X axis drive motor and timing belt (this is so exciting!). Video sequence 2:34-2:55.

  1. Attach the X drive motor (2:34) using four M3 6mm bolts. Pay attention to the orientation of the power plug, which should be down. As before, the drive pulley will be loose. Leave it loose.
  2. Slide the pre-assembled extruder head onto the extruder crossbar. Make sure the extruder head is pointing down (2:36)
  3. Attach the acrylic bearing to the acrylic bearing mount (2:41). This is the same style of pre-assembled bearing as we used for the Y timing belt (step D5).
  4. Attach the acrylic bearing mount to the crossbar (2:45) using two M4 8mm bolts and two T-nuts.
  5. Insert the timing belt (2:50), align it with the bearing and drive pulley, and pull it through the small holes in the extruder assembly shown at 2:52. Note the orientation of the timing belt, is with the teeth inwards, unlike what is shown in the video. Pull on the timing belt to tighten it and secure it with zip ties. Then make sure the drive pulley is correctly aligned, orient it so that one set screw is on the flat part of the drive shaft, and tighten.

F. Attach the extruder motor (2:56-3:03)

  1. Find the extruder assembly, which is in its own separate plastic bag and made of black metal. In the same bag, you will find a very short M5 (I think) bolt which requires a hex wrench to tighten. As shown in the picture below, it will fit into the larger extruder assembly piece, which has the bearing attached to it as well. Make sure the bolt in that piece is all the way in so it can sit in the inset hex-shaped area in the bolt (mine wasn’t). You will also find a spring, which goes over the bolt and sits in the other side of the extruder assembly. Watch the video a few times from 2:58-3:00 to see how this all fits together.
  2. Find the extruder motor. Make sure that the teeth are at the top of the motor shaft (you may need to loosen the set screws to do this). Note: The set screws on this motor are NOT metric. You will have to borrow a tool or buy a non-metric hex wrench set to adjust the position of these screws.
  3. Find an M3 22mm screw in the extruder assembly and use it to attach the motor to the motor mount  (note: orientation of the assembly is important. See picture). Make sure the power plug faces to the back for the motor.
  4. Find the next M3 15mm bolt in the same bag and attach the rear right of motor
  5. Squeeze the extruder assembly together and attach the front left of motor with the final M3 22mm screw. Note that there is no place for a fourth screw.
  6. Find the small brass holder for the bowden cable. Insert the bowden cable into it, and screw it into the front of the extruder assembly.

G. Attach the end stops and print bed (3:04-3:18)

  1. Find the end stop with the longest cord and the acrylic mount shown at 3:04. Get two M2 10mm bolts and two M2 nuts and attach the end stop to the acrylic piece. Use two T-nuts and two M3 8mm bolts to attach the assembly to the X-axis crossbar (that the extruder is mounted on). At this point I discovered I was short a couple of T-nuts. We have extras ordered for your kits.
  2. Find the last end stop (the z axis end stop) and acrylic mount shown at 3:10. Note that the orientation of the printer in the animation is backward — the back of the printer is facing you (you can see the power plug in the motor) and the front is away from you. This means that the end stop looks like it’s being mounted on the rear, right side of the printer but it actually belongs on the front, left side, as is visible at 3:15 in the video.
  3. Find the print bed, 4 M3 30mm bolts, 4 wing nuts, 4 regular nuts, and 4 springs. You also need 4 M3 nuts to secure the print bed above the spring. Attach the bolts to the metal bed with the regular nuts. Arrange as shown at 3:18. For orienting the print bed, the writing should go down and the power plug face to the back.

H. Assemble the electronics (3:21-4:00)

  1. Find the powerbox, electronics base (acrylic). Note the bright yellow sticker marking the switch between 110V and 220V. Before you do anything else, make sure the switch is all the way to the left!
  2. Find the 3 M3 10mm bolts. Position the power box as shown at 3:21. Hold it in place as you turn the assembly over to find the bolt holes (Note: I was only able to match it up to 3 hols and bolts, but the video shows 4).
  3. Find four M3 20mm bolts and place them through the bolt holes shown at 3:26, putting plastic pillars on them once they are through the holes. This is a tricky maneuver as they want to fall out as you re-orient the electronics base.
  4. Find the long (5mmx21mm) green circuit board and place it with the USB port facing out (away from the power supply) in the position of the bright green rectangle in the video at 3:27. Secure with nuts as shown.
  5. Find an M3 20mm bolt and M3 nut and move the video to 3:29. The assembly order in the video is difficult. It is much easier to slide the bolt through the hole and place the nut on the bolt at the very top. Then place the plastic piece and adjust until the nut is in the inset shown in the video. Now tighten the bolt, and the plastic piece will be tightened into place.
  6. Follow the same procedure to attach the piece shown in green at 3:34, using two M3 20mm bolts, and the piece in green shown at 3:38. Note the orientation and shape of the pieces, in particular, make sure that the USB port is accessible.
  7. Find the switch and plug shown at 3:42 and attach them to the corresponding acrylic piece with two M3 10mm bolts and M3 nuts.

I. Wiring your power supply (not in video).

  1. Wiring your power supply is a very important thing to get right!! Although it is not described in the video, your printer comes with a piece of paper that shows the wiring. With careful attention, wire the power supply to the switch as shown. Have the instructor check this if you have any concerns. It will wreck your electronics if you get it wrong.
  2. Also attach the free (both ends unattached) black and red wires as indicated to V- and V+, respectively.
  3. Now you can attach the back to the electronics base, as shown at 03:45.
  4. Turn over your piece of paper to see the wiring for the board.
  5. Attach the grey cable for the display to the board, and attach the display to the electronics base as shown at 03:52.
  6. Attach the wires labeled X, Y, Z1, Z2 and E to the correct locations on the board. Be sure to attach the correct side of the wires, and orient them the correct way. You can see by shape, as well as the color ordering of the wires in the picture and in your board. Run the wires along the top of the board and out the big hole near the power supply.
  7. Find the wires coming out of the extruder assembly. Push them through the same big hole as everything else, and wire them up. Plug in the fan, and thermistor wires as well.
  8. Plug the hot bed wires into the hot bed (these are difficult to get in, but the clasp should be on top). Push them through the same hole as everything else. Plug in the bed thermistor.
  9. Three sets of wires on your board are screwed in instead of plugged in.These are the extruder heater wires, the hot bed heater, and the power supply. Take very careful note of where each goes.Use the small yellow standard screwdriver to unscrew these screws. You have to raise the screws quite a lot to get the wires in properly. You’ve done it right if, once you tighten the screws down, the wires won’t come out. Be sure to put the black (V-) and red (V+) wires from the power supply in the proper order.
  10. Plug in the end stops. On the board, they have labels like ‘X-axial limit switch’ (X end stop). Also plug the motor wires into the motors, and you should be all wired up.
  11. Do not attach the cover to your wire box, as you probably made at least one mistake. 
  12. Also don’t do this yet, but eventually: You can use the wire wrap to wrap your wires. The picture of the printer on the Alunar site shows very nicely which wires you want to wire wrap together.

J. Prepare your mac for connection to your board

  1. Install the CH34OG Driver (Serial adapter) website and instructions if that doesn’t work after restart (for later versions of osx):
  2. Download Repetier Host
    1. The repetier software download website :
    2. In order to get your printer running, you will need to change a few settings. Use Command or Control P to open the printer settings. In the connection tab, set the Port to the serial port your printer will be using, set the Baud Rate to 115200, set the Transfer Protocol to Force ACII Protocol, and set the Receive Cache Size to 127. Also make sure that Use Ping-Pong Communication and Firmware sends OK after error are checked. Then go to the dimensions tab and fill in the correct dimensions for your printer (220 x 220 x 220 should work).
  3. Install the FTDI usb driver. Download website:
  4. Begin testing. When everything works, then cover it :).

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