Skip to content

Y Gantry


The purpose of this work instruction is to explain the assembly process for the LumenPnP v3.2.0 Left-Side Y-Gantry (y-gantry-left).

Create Y-Gantry Subassembly

  • Remove any stringing from the print with a heat gun
  • Insert 6x m5-hex-nut into the following region

Create Front-Left-Leg Subassembly

Prepare front-left-leg

  • Remove any stringing from the print with a heat gun
  • Insert 3x m5-hex-nut into the following regions

    • 2x in bottom of the leg for customer-side front-leg-extension mounting
    • 1x near extrusion pocket for customer-side attachment of front-drag-chain-mount
  • Insert 1x m5-nylock-hex-nut into in the underside of belt-tensioner-arm mounting post

Prepare belt-tensioner-arm

  • Press an M3-hex-nut into the belt-tension-arm with a arbor-press-jig
  • Thread a M3x16-bolt through the belt-tension-arm
  • Thread a M3-acorn-nut onto the end of the bolt

    • The M3-acorn-nut and M3-hex-nut should be on the same side of the belt-tensioner-arm
    • Tighten the M3-acorn-nut onto the M3x16-bolt with a 5.5mm socket and an allen wrench

  • Rotate the M3x16-bolt until the M3-acorn-nut is loosely resting against the M3-hex-nut

    This ensures the belt-tensioner-arm is installed with it's adjustment range fully available for when it's time to tension GT2-belt

  • Insert a M5-nylock-hex-nut into belt-tension-arm's hex-nut pocket

  • Slide a GT2-idler-pulley into the belt-tensioner-arm

    Note that the GT2-idler-pulley is symmetrical, so it's orientation does not matter

  • Install a M5x25-bolt into the belt-tensioner-arm to secure the GT2-idler-pulley in place

    • Avoid over tightening this bolt as the GT2-idler-pulley should be able to spin freely without resistance
    • The bolt should, however, be tightened enough to eliminate lateral pulley movement within the belt-tensioner-arm

Install belt-tensioner-arm onto front-left-leg

  • Add a drop of ptfe-silicone-lubricant to both sides of belt-tensioner-arm's pivot point

  • Install belt-tensioner-arm onto front-left-leg

  • Secure the belt-tensioner-arm onto front-left-leg with a M5x40-bolt

    • Avoid over tightening this bolt as the belt-tensioner-arm should be able to pivot freely without much resistance

  • The completed front-left-leg should match the image shown below

Create Back-Left-Leg Subassembly

Prepare back-leg

  • Remove any stringing from the 3D print with a heat gun
  • Insert an m5-hex-nut into the bottom of the back-leg 3D print
    • Finger strength should be sufficient to install this fastener into position

    Glue if needed

    Add a drop of loctite to the region if the fastener fit is looser than normal and seems at risk of falling out in transit

Prepare y-gantry stepper motor

  • Gather the following parts and tools

    • nema17-stepper-motor
    • GT2-timing-pulley
    • y-timing-pulley-spacer-jig
    • Torque driver w/2mm hex driver, set to 0.7 N/M (not shown)

    - Use motor spacing jig to mount the timing pulley to the NEMA 17, ensuring the set screw is aligned to the flat side of the motor shaft - Tighten the 2x timing pulley set screws to 0.7 N/M - first tightening the one facing the flat on the motor shaft

Install y-gantry stepper motor onto back-leg

  • Connect Y1-stepper-motor-cable to the y-gantry-stepper-motor

  • Install the y-gantry-stepper-motor onto back-leg

    • The Y1-stepper-motor-cable should be routed through back-leg to exit towards the center of the machine
    • Ensure no wires are being crushed or strained

  • Put 4x M3x8-bolt through the motor mounting holes found on back-leg

  • Install a zip-tie for cable strain relief

    • Use a zip-tie to attached the Y1-stepper-motor-cable to the back-leg to add strain relief

    • Cut the zip-tie with flush-cutters

    • Ensure that Y1-stepper-motor-cable and zip-tie are resting against the logo-face side of back-leg

Assemble y-gantry-left

Install front-left-leg and back-leg onto 600mm-alu-extrusion

  • Begin by inserting a 525mm-m3-t-nut-bar into a piece of 600mm-alu-extrusion

    • There should be about 51.5mm between the end of the 525mm-m3-t-nut-bar and the right-side end of the 600mm-alu-extrusion after installation
    • The 525mm-m3-t-nut-bar needs to be slide aside in later steps, so do not bother to make this perfect right now

  • Insert front-left-leg and back-leg onto 2x pieces of 600mm-alu-extrusion

    • The 525mm-m3-t-nut-bar is oriented in the top-side groove of the uppermost 600mm-alu-extrusion
    • The extrusion pieces should be fully inserted into each leg

  • Bolt back-leg to 600mm-alu-extrusion

    • Insert 3x m3-t-nut into the 600mm-alu-extrusion pieces before sliding each of them into alignment with the matching bolt holes on back-leg

    • Insert 3x M5x10-bolt into back-leg and thread the bolts into each corresponding M3-t-nut

  • Bolt front-left-leg to 600mm-alu-extrusion

    • Slide the M3-t-nut-bar out of the way if needed
    • Insert an M3-t-nut into the upper channel of 600mm-alu-extrusion
    • Align the M3-t-nut with the top-side bolt hole on front-left-leg

    • Insert a M5x10-bolt into the top-side bolt hole on front-left-leg and tighten it into the M3-t-nut

    • Slide 2x M3-t-nut into the the side channel of lower 600mm-alu-extrusion and align them with the two bolt holes on front-left-leg

    • Insert 2x M5x10-bolt into the side bolt holes on front-left-leg and tighten each into the corresponding M3-t-nut

  • Compare the WIP y-gantry-left assembly to the image below after completing all previous steps, address any discrepancies as needed before proceeding onward

Install linear-rail-550mm

  • Roughtly position linear-rail-550mm onto top-side of uppermost 600mm-alu-extrusion

  • Place a linear-rail-2020-alignment-jig on both ends of linear-rail-550mm

    • Do not cover any bolt holes with the jig

  • Visually center the linear-rail-550mm between the back-leg and front-left-leg

  • Slide the M3-t-nut-bar to line up with the linear rail's bolt hole pattern
  • Starting from the front-left-leg side, lightly snug a M3x8-bolt into every other bolt hole on linear-rail-550mm

    • Move the linear-rail-carriage out of the way as needed

  • Torque the rail mounting bolts to specification in sequence beginning with the bolts at the center of the rail and working towards each end.

    • A torque wrench should be used to set the specified bolt torque
    • The torque specification for these M3x8-bolts is 0.5N/M

  • Remove the linear-rail-2020-alignment-jig from both ends of linear-rail-550mm

  • Slide the linear-rail-carriage back and forth a few times, checking to see that it travels smoothly and consistently

Halfway Checkpoint

  • Verify that y-gantry-left matches the following photo

If y-gantry-left matches the photo, proceed to the next section

If y-gantry-left does not match the photo, correct discrepancies before proceeding to the next section

Install GT2-belt

  • Route a 1.3m-long piece of GT2-belt through y-gantry-left

    Belt routing step-by-step

    - Start by running the belt through the `y-gantry`'s left-side slot and leave 75mm of extra belt poking out 
    - Run it through the extrusion towards the `back-leg`
    - Wrap it around the `timing-pulley`
    - Run it back through the extrusion towards the `front-left-leg`
    - Wrap it around the `idler-pulley`
    - Run it back through the extrusion towards the `back-leg` again
    - Have the belt exit through the `y-gantry`'s right-side slot

  • Slide the y-gantry subassembly onto the linear-rail-carriage while pulling slack out of the GT2-belt

  • Bolt y-gantry to the linear-rail-carriage with4xM3x8-bolt`

    • Tighten each bolt to 0.5 N/M
    • Push y-gantry inward towards the `linear-rail-carriage while tightening the mounting bolts to align it

    Ensure that y-gantry sits flush against linear-rail-carriage without any visible gaps

  • Use belt-clamp with 2x M5x10-bolt to clamp the left-side of the GT2-belt to the y-gantry

    • Tighten each M5x10-bolt to 0.5 N.M

Tension the Y-Gantry

  • Pull the right-side GT2-belt tightly towards front-left-leg

  • Use belt-clamp with 2x M5x10-bolt to clamp the right-side GT2-belt to the y-gantry

    • Tighten each M5x10-bolt to 0.5 N.M

  • Rotate the M3x16-bolt clockwise on the belt-tensioner-arm to tension the GT2-belt installed on y-gantry-left

    • This will cause the belt-tensioner-arm to pull the idler-pulley away from the front-left-leg which adds desired tension to the GT2-belt

  • Trim the loose GT2-belt on either side of the y-gantry

    • For the front-left-leg side of the y-gantry print, trim the loose GT2-belt until it's flush against the belt-clamp
    • For the back-leg side of the y-gantry print, trim the loose GT2-belt until there's approx. 15mm of GT2-belt past the belt-clamp

Add cable management

  • Use 3x extrusion-cable-clip to secure the Y1-stepper-motor-cable to the inner side of the lower 600mm-alu-extrusion

Quality Checks

A y-gantry-left that was built while following the above steps will match the following image.

Confirm this by inspecting the completed y-gantry-left assembly with the following QC checklist:

  • Confirm M5 bolts are installed in every counterbored region
  • M5-hex/square-nut installed where required:
    • 2x M5-hex-nut pressed into bottom of front-left-leg
    • 1x M5-square-nut pressed into side of front-left-leg for use with front-drag-chain-mount
    • 1x M5-hex-nut pressed into bottom of back-leg
    • 2x M5-hex-nut pressed into y-gantry
  • GT2-belt has been trimmed to appropriate length (flush on 1 side, ~1/2" - 3/4" on the other)
  • GT2-belt has been correctly tensioned
  • Tensioner-arm is installed on front-right-leg in the correct orientation (IE acorn-nut facing touches leg)
  • Linear-rail is centered atop aluminum-extrusion
  • y-gantry sits flat on linear-rail-carriage
  • y-gantry feels smooth and free of friction across the y-min to y-max travel range when actuated by hand
  • GT2-belt lays flat in the 600mm-alu-extrusion channels
  • 3x extrusion-cable-clip have been installed onto the y-gantry-left's lower 600mm-alu-extrusion
  • Timing-pulley is tightened down and at proper height
  • Y1 cable is secured with a zip-tie and exits the port labeled Y1

Stay vigilant for new failure modes not listed above and report them to a production lead when found

If everything looks good

Set the finished y-gantry-left aside for functional QC testing at the Gundam test station