Project Dashboard LulzBot Mini 2 Y-Axis Sub-Assembly Workflow

1 Components and Hardware

Gather parts:
1x- [AS-PR0102] Mini, Bed Plate Assembly 1x- Frame Assembly 1x- [AS-CB0071] Min2 Bed Harness
1x- [PP-GP0249] bed clip v3
4x- [HD-BT0128] M3 x 6 Bolt, FHCS Black-Oxide
8x- [HD-BT0137] M3 x 8 Bolt, BHCS, Black-Oxide
1x- [HD-NT0001] Metric Zinc-Plated Steel Nylon-Insert Locknut, M3 Screw size, .5MM pitch
12x- [HD-WA0038] Black-Oxide 18-8 Stainless Steel Flat Washer, M3 Screw Size, 3.2mm ID, 7.0mm OD
1x- [EL-MT0029] NEMA 17 Stepper Motor
4x- [HD-BT0140] M3 x 6 Bolt, BHCS Black-Oxide
1x- [HD-MS0033] GT2, 16 Teeth, timing pulley, AL
2x- [HD-MS0058] 8" cable tie

Tools needed:
2mm hex driver
5.5 Nut Driver
Flush Cutters
1.3mm Hex Driver
P2 Phillips screwdriver

Components required
Components required

2 Attach AS-CB0071 to Bed Plate Assembly

Place the Bed Plate Assembly plate side down onto the work station

Route the Yellow/ White wire pair as well as the Green, Gray, Brown, and Pink wires through the last slot in the cable chain; using a standard screwdriver, open the last two backside access latches, send wires through the last slot in the top side of the chain, see [reference#1] , close the latches

Attach AS-CB0071 (Bed Harness) to the Bed Plate Assembly with two M3x 6 FHCS [HD-BT0128], tightened to 5in*lbs

Connect the two ring terminals from the cable harness to the screw, Secure the ring terminals to the screw with a M3 Nyloc nut [HD-NT0001] tighten until the ring terminals no longer move and the SS screw head remains flush and tight to the bed plate.

Insert the Green & Gray wires to the pockets on the rear of the Bump Stop on the front (idler side) and the Pink & Brown into the back (motor side) Bump Stop

Tie the two pairs together with a cable tie with the cable tie

Install the bed clip; there is a small notch out of one side of the latch, that notch faces the double bearing holder.

Bed Plate Assembly face down on workbench
Pry open the last two backside access latches
Backside access latches open, cable pulled back
[reference#1] EndStop & Thermistor wires through last slot
Close the latches
Align cable chain mount with the two holes shown on the bed plate
Attach with two M3x6 FHCS, torque to 5in*lbs
Place both terminal rings on the stainless screw protruding from the bottom of the bed plate
Secure with M3 nyloc nut [HD-NT0001]
Tighten M3 Nyloc Nut with 5.5mm nut driver
Insert endstop plugs into pockets on rear of bump stops as shown
Tie wires together with a cable tie [HD-MS0058]
Install the bed clip as shown

3 Install Bed Plate Assembly w/ Harness onto Frame

Lay a piece of protective foam over the motor mount of the frame's bottom plate, and place the Bed Plate Assembly face down on top of it with the Rod Mount & Bed Harness end towards you, see [reference#2]

Carefully insert the end of the Bed Harness through the Lower Strain Relief mounted to the Left Frame Plate as pictured

Align the cable chain mount with the two holes in the Bottom Plate and secure using two M3x6 FHCS [HD-BT0128], torque to 5in*lbs

Cables inside of the cable chain must not cross or overlap one another See [reference#3]

Carefully flip the Bed Plate Assembly into position as shown.

Lean the frame towards the rear (it will rest on the Y-Axis Motor Mount of the Frame)
Using 4x M3x8 BHCS [HD-BT0137] with washers [HD-WA0038] secure the Y-Axis Idler to the Bottom Plate
Make sure the front of the Idler printed part remains flush with the idler mount of the Frame. It should be centered between the left and right sides of the mount as well.
Torque fasteners to 5in*lbs

Rotate the frame so that the rear of the frame is facing you.
Lean the frame away from you to expose the screw locations for the Y-Axis Rod Mount
Secure the Y-Rod Mount to the Motor mount flange of the bottom plate using 4x M3x8 BHCS [HD-BT0137] with washers [HD-WA0038]
Make sure the back of the Y-Axis Rod Mount printed part remains flush with the motor mount flange of the Frame. It should be centered between the left and right sides of the mount as well.
Torque fasteners to 5in*lbs

Lay protective foam over Y-Axis motor mount flange
[reference#2] Lay the bed plate assembly face down on the protective foam
Carefully guide the bed harness through the lower strain relief
Secure the cable chain mount to the bottom plate w/ 2x M3x6 FHCS; torque to 5in*lbs
[reference#3] Cables inside the cable chain must not cross eachother
Bed plate flipped into position
Secure the Idler
Idler secured; torque fasteners to 5in*lbs
Secure the Rod Mount
Rod Mount Secured; torque fasteners to 5in*lbs

4 Install Y-Axis Motor

Install a Pulley [HD-MS0033] to the shaft of a Motor [EL-MT0029] using the printed spacer jig to offset the pulley 2mm from the face of the motor.
Align the first set screw to be tightened with the flat side of the motor shaft, tighten both set screws securely.

Align the motor with the Y-Axis Motor mount of the frame with the connector oriented as shown
Secure using 4x M3x6 BHCS [HD-BT0140] with washers [HD-WA0038]
Torque to 5in*lbs

Flip the frame over so that it rests on the top plate.
Route the Y-Axis Motor lead through the hole in the rear of the bottom plate.
Remove the phillips head screw from the bottom of the motor, closest to the frame and connector [see reference#4]
Install the terminal ring to the screw and re-install the screw, ensuring that it again becomes recessed and tight.

Connect the JST connector to the motor as pictured
Secure the Y-Axis Motor lead to the frame utilizing the two small holes in the bottom of the frame and a cable tie [HD-MS0058]
The cable tie latch must be on the bottom of the frame.

Use printed jig to offset pulley ~2mm from the face of the motor, tighten the first set screw on the flat side of the motor shaft
Tighten both set screws securely
Align motor with Motor Mount flange of frame Note: orientation of the motor connector is critical
Secure the motor using 4x M3x6 BHCS with washers; torque to 5in*lbs
[reference#4] Ground Terminal Ring location on Y-Axis Motor
Install the terminal ring to the screw and re-install the screw, ensuring that it again becomes recessed and tight.
Connect the JST connector to the Motor
Secure Y-Axis motor lead to the bottom frame plate using a cable tie, cut excess cable tie length flush with the latch

5 Tighten bearing holders to Bed Plate

Flip the frame back upright and rotate if necessary so that the Y-Axis Idler is facing you.
Using a 2mm hex driver, tighten the double bearing holders to the Bed Plate, beginning with the left two flat head screws (1 & 2)
Then tighten the two M3x8 BHCS directly to the right of the two flat head screws (3 & 4)
Slide the bed towards the rear and tighten the back right M3x8 BHCS securing the right double bearing holder to the bed plate (5)
Slide the bed towards you and tighten the front left M3x8 BHCS securing the right double bearing holder to the bed plate (6)
Tighten the remaining two M3x8 BHCS (7 & 8) and torque the six button heads to 3in*lbs and the two flat heads to 5inlbs.

Slide the Bed Plate back and forth and ensure that motion is smooth from end to end without binding.
If stiffness or binding occurs it may be necessary to loosen and re-tighten the bearing holders while moving the Bed Plate, this helps align the bearing holders with the smooth rods.

Torque fasteners to 5in*lbs

6 Check the carriage drag

Using the force gauge, measure the carriage drag as shown. If the drag is above 15N, check the individual bushing drags. If needed, carefully broach the bushing set to reduce the drag with the special broaching tool for a maximum of one pass.

Materials
Pull on the force gauge
Make sure the bed power harness does not interfere with the test

7 Check your work

Verify that what you've assembled matches the picture at right.

Complete Frame & Y-Axis Assembly
Done! Take me home