Tribotron 3D Printer

About: Hey there!

These are the current build instructions for my first custom made 3D printer codename Tribotron.

You can find the full source materials (printed parts, BOM, Firmware) on Thingiverse!

While I try to step through the most important build steps, this instructable assumes prior experience in building "things" and/or 3D printers more specifically, but if you have any questions feel free to ask! :)

Step 1: Mainframe

For this step these materials are needed:

  • 2040 460mm x 8 (top/bottom).
  • 2020 540mm x 4 (corners).
  • 2020 460mm x 2 (back).
  • 2020 460mm x 1 (bottom).
  • Corner Bracket 40x40 x 8 (fastening top/bottom).
  • Corner Bracket 20x20 x 44 (fastening everything else).
  • M5x8mm x 120 (fastening everything).
  • M5 T-Nut x 120.

I found the easiest way to build the frame is to build the bottom along with the vertical extrusions then rotate the frame upside down and build the top. Whatever way you chose to build it though, make sure it's as nice and square as possible. (Please note that the images do not include the 2020 corner brackets).

  1. Each of the vertical extrusions on the back is about 100mm away from it's respective side, but precise distance is not critical.
  2. The extrusion on the bottom of the frame is about 130mm away from the front, but do not fasten this down tight just yet, since it will probably require adjusting once the belt is done. Let it loose for now.

Step 2: Leadscrews

Materials:

  • Leadscrew T8 500mm x 3.
  • Pillow Block Bearing KP08 x 3.
  • Pulley GT2 20T Bore 8mm x 4.
  • M5x8mm x 6.
  • M5 T-Nut x 6.

Image shows a 60T on the back. This is possible if you want to increase torque, but I ended up using a 20T which works fine. This pulley on the top of the bearing is used to drive the leadscrew system by the motor, while the other 3 on the bottom will be connected together by a closed timing belt later on.

Step 3: Z Belt Tensioner

Before continuing with the Z axis build and belts, this little and rather simple belt tensioner needs to be build. Materials:

  • The printed parts.
  • 605zz Ball Bearing x 2 (fastened idlers).
  • 20T Idler Bore 3mm No Teeth x 1 (tension idler).
  • M5 Metal Spacer 3mm x 4.
  • M5x25mm x 2.
  • M5 T-Nut x 2.
  • M5x40mm x 1.
  • M5 Nut x 1.
  • M3x20mm x 2.
  • M3x12mm x 1.
  • M3 Nut x 1.
  • GT2 Closed Belt 1524mm x 1.
  • Stepper Motor.
  • 20T Pulley Bore 5mm x 1.
  • M5x10mm x 2.
  • M3x10mm x 4.
  • GT2 Closed Belt 158mm x 1.
  1. Make the tension idler. This will be placed between the top and bottom parts and will slide back and forth to tension the belt.
  2. Make two of these idlers out of a 605zz, the printed part and 2 x 3mm spacers.
  3. Place an M5 nut inside the hole in the front and the M5x40mm bolt throw the front.
  4. Important: Before closing the sandwich, make sure to roughly pass the belt between the idlers, because once this is closed it's not possible (unless of course you open it again).
  5. Once the mini tensioner system is build, rotate the frame upside-down and fix it at the center of the extrusion.
  6. Pass the three points of the belt around the three leadscrew pulleys and screw the long bolt in the front to tension the belt.
  7. Last but not least, drop the small 158mm belt within the back leadscrew, and fix the motor with the bracket part.

Step 4: Z Axis Linear Guides

Materials:

  • Printed Parts.
  • MGN12H 450mm x 2.
  • M3x8mm x 4 or more.
  • M3x10mm x 8.
  1. Fix the 450mm Linear Guides on the two extrusions on the back. Make sure that the starting point of the linear guide at the top, is aligned with the extrusion. Since these extrusions on the back are 460mm, there will be a 10mm gap at the bottom. Because we want the guides to be as parallel as possible, I suggest to not tight down the guides now, but rather once after the bed is fixed on the guides.
  2. Fix the printed bracket part on the MGN carriage with all 4 M3 bolts for each one.

Step 5: Bed

It's time to build the bed. It is best to build it separately and then add it to the frame, but there are many ways to go about this. This is just one of them.

Materials:

  • Printed Parts.
  • 2020 Extrusion 400mm x 2.
  • 2020 Extrusion 420mm x 1.
  • Corner Bracket 20x20 x 2.
  • Leadscrew Nut Block x 3.
  • M5x10mm x 15
  • M5 T-Nut x 15
  • M3x40mm + Spring + Thumb Nut x 3.
  • MK3 Heated bed 300x300.
  • Thermistor 100K NTC 3950.
  • Ultrabase 300x300.
  • M5x10mm x 6.
  1. The left and right side Nut Blocks are about 51mm away from the front end of the extrusion, while the Nut Block on the back is once again on the very center of the extrusion.
  2. The M3 Thumb Nuts are inserted into the printed part using a soldering iron (similar to how it's done for threaded inserts). This is of course optional and you can keep the Thumb Nuts "naked".
  3. Because I opted for a 3 point bed mounting, notice that the heated bed is rotated so that the cables come
    from the left side of the bed. At least on the heated bed that I bought, the soldering pads were on the center of the side, so it was impossible not to rotate the bed like this.

Once the bed is build, you can add it to the mainframe from the top and into the leadscrews. Considering that the z axis belt is tensioned from the previous step, the three leadscrews will be able to hold the bed weight just fine.

Once the bed is inserted, slide the linear guide brackets upwards into position and fix them with the bed using 3 M5x10mm for each.

TIP: To ensure the two linear guides are as parallel thus smooth as possible, unfix the bottom bolt from each of the two guides and move the bed down till the end of the linear guide length (by pulling the belt). Once the bed is moved down, fix the bolts again. Then, do the same in reverse; unfix the top bolts, move the bed up and fix them back again. This is something I've found works for me, but you might have better solutions :)

Finally and optionally, place the three leadscrew printed brackets at the top. These are not very important, but rather mostly an aesthetics step.

Step 6: Z Endstop

Materials:

  • Printed Parts.
  • Limit Switch.
  • M3x10mm x 4.
  • M3x30mm or more x 1.
  • M3x8mm + Nut x 1.
  • M2.5mm x 2.
  • M3 T-Nut x 4
  • Drag Chain ~250mm.
  1. This part on the top is for adjusting the (mechanical) minimum z by screwing/unscrewing a long M3 bolt which will in turn contact the limit switch on the bottom.
  2. This part on the bottom (fixed on the bed frame) has the limit switch fixed. Make sure that the long M3 used on the top part and the limit switch are aligned!.
  3. The bottom part is also used to fix one end of the drag chain that will lead the cables from the heated bed (as well as the limit switch) down to the main board. The other end of the drag chain is simply fixed on the vertical extrusion on the right (of the image) and at the very bottom.

Step 7: The Z Axis Is Done!

Step 8: Y Axis Linear Guides

Materials:

  • MGN12H 400mm x 2.
  • M3x8mm x 4 or more

Fix both y axis linear guides respectively and make sure that you push them back, so that they contact the corner brackets on the back. Once again, don't tight the bolts down a lot just yet. Once the x axis is placed and fixed, it will be easier to make sure that the linear guides are as parallel as possible by repeating the same trick as we did for the z axis.

Step 9: XY Joiner

This is probably the most tricky part of the build.

Materials:

  • Printed Parts.
  • 2020 Extrusion 420mm x 1.
  • M3x20mm + Nuts x 4.
  • M3 Washer x 4.
  • M3x10mm x 8.
  • M5x10mm x 6.
  • M5 T-Nuts x 6.
  • Pulley 20T Bore 3mm No-Teeth x 4.
  • MGN12H 400mm x 1.
  1. Before anything else, slide two M5 T-Nuts on the bottom of the extrusion and another one on the top! Once that is done, push the extrusion into the bracket part.
  2. Place an M3 Nut in each of the holes on the back of the bracket part.
  3. Place the two pulleys in-between of the two parts and fix the top part to the bottom one using two M3x20mm bolts. These two bolts don't need to be super tight, but rather "just enough" so that the pulleys are moving freely and smoothly. I strongly suggest adding a washer on the bottom of each pulley as well!
  4. Fix the extrusion on both bottom and top parts of the bracket using the previously inserted T-Nuts and three M5x10mm bolts. Do not tight the bolts down just yet!


Repeat for the other side.

  1. Now with both sides done, "slide" the gantry between the Y axis linear guide carriages. The clearance should be tight, but it's not a problem if not. Just be careful not to drop the gantry!
  2. Fix the left and right bracket parts respectively onto each carriage using four M3x10mm for each. I suggest fixing the bottom two bolts first since they are way easier and only then fixing the top two (which are also very tricky and unfortunately hard to reach). Once the gantry is fixed onto the Y axis carriages, go back and tight the bolts explained in step (4) above.
  3. Fix the x axis linear guide (400mm) on the gantry.

Now slide the gantry back and forth and adjust the y axis linear guide bolts to ensure a smooth motion.

I suppose the gantry bracket parts need a redesign, but it is what it is right now. Sorry! :)

Step 10: Hotend Mount

Materials:

  • Printed parts.
  • M3 Threaded Insert x 8.
  • Hotend + Thermistor.
  • Fan 4010 Axial.
  • Fan 5015 Radial.
  • M3x8mm x 4.
  • M3x12mm x 4.
  • M3x16mm x 8.
  • M3x25mm x 4.
  • M3 Nuts x 6.

Important Note: The four side M3 holes of part (1) as well as all four M3 holes of hotend bracket part (2), are to be used with an M3 Threaded Insert, pushed in with a soldering iron. Nuts are avoided here due to very tight spacing, but threaded inserts are awesome anyways! :)

  1. The mount part is actually made out of two printed parts that "almost" snap together. Place these on the carriage. Do not fix anything! Just let it be there. It should not fall, but if it tents to, you can fix one or two bolts temporarily on the carriage.
  2. Slide the hotend + thermistor cables as well as the hotend itself from the bottom into the hole. The cables should then slide back into the smaller opening. Place the bracket on the "neck" of the hotend and fix it onto the mount part.
  3. Fix the 4010 fan with 16mm bolts + nuts onto the fan housing part. The cables of the fan should come out from the top. The part has an opening for the cables to come through. Place the fan housing part on the mount and fix it.
  4. These are two parts. Sandwich the 5015 Fan between the two parts with 25mm bolts + nuts. Place the fan on the mount and fix it as well.
  5. This is the cable connector housing. It is mostly an aesthetics part to hide the connectors, but it also helps a little bit holding the weight of the drag chain (added later).

Parts (4) and (5) should really be added AFTER the XY belt is clamped. Because the belt is clamped on the back of part (1), adding part (4) now will obscure the position where the belt is clamped. Just go on with the next instructions step and add part (4) and (5) once that is done.

Step 11: XY Belt

Materials:

  • Printed Parts.
  • Stepper Motors x 2.
  • 20T Pulley Bore 5mm x 2.
  • GT2 Belt.
  • M5x10mm x 6.
  • M3x10mm x 8.
  • 605zz Ball Bearing x 2
  • M5x15mm x 2.
  • M5 Washer x 2.
  • M5 Metal Spacer 5mm x 2.

Fix the X and Y motors on the brackets and the brackets on the frame respectively. Ideally, motor cables should come to the inside, meet at the vertical extrusion (3) and go downwards to the main board.

Similarly to the idler we made for the the Z axis belt tensioner, two more made the same way are needed, using one 605zz ball bearing and the printed part for each one respectively. Fix the idlers on the left and right side of the frame in the front with M5x15mm bolt. Make sure to use a 5mm spacer and a washer on the bottom side. Make sure for them to be as much aligned with their respective opposing motor as possible!

Drive the belt around and clamp the two ends at the back of the gantry carriage mount part, by sliding the belt endpoints from underneath the clamping place.

Step 12: Ensure Belt Alignment

Make sure the belt is as parallel and aligned as much as possible with the gantry idlers.

  • To adjust horizontally, move the idlers on the front left or right.
  • To adjust vertically, move the X and Y motor pulleys up or down and if necessary, use a different length spacer for the idlers on the front.

Step 13: XY Endstops

Materials:

  • Printed Parts.
  • Limit Switch x 2.
  • M3x10mm x 4.
  • M2.5 x 4.

Pretty straightforward as it looks, simply fix the limit switches on the relevant parts and the parts on the extrusions. Both X (1) and Y (2) parts touch the corner bracket, but feel free to adjust if required. The Y (2) part has a gap for the linear guide to pass through, so they are easy to distinguish. Both limit switch cables are on the inside and ideally go to the main board alongside the vertical extrusion (3).

The X axis limit switch is fixed on the frame rather on the moving gantry, because in firmware the HOME_Y_BEFORE_X option must be enabled! To avoid the X carriage from crashing the limit switch when homing right after another home, SAFE HOMING is also utilized. Please check the firmware thoroughly.

Step 14: Extruder & Spool

Materials:

  • Printed Parts.
  • Stepper Motor x 1.
  • Extruder Kit x 1.
  • M5x10mm x 8.

The extruder is mounted a bit to the center of the frame rather than the front for example, to minimize the length of the teflon tube needed, but in doing so maximizes the length of the cable to reach the board which is on the other side. I suppose though that a longer cable is better than a longer tube.

Having said that you can of course just mount the extruder on the left side :)

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