Y Gantry

Intro

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