Project Dashboard LulzBot Mini 2 Final Mechanical Assembly Workflow

1 Components, Hardware, and Tools

Components Required:
1x- [AS-PR0101] Frame Assembly
1x- [AS-PR0099] Z Axis left Assembly
1x- [AS-PR0089] Z Axis right Assembly
1x- [AS-PR0086] X Carriage assembly
1x- [AS-TH0066] Titan Aero Assembly, Mini 2
1x- [AS-PR0107] Spool Arm Assembly, Mini 2
1x- [AS-EL0002] Mini 2 LCD Assembly
1x- [PP-GP0320] X carriage cap
2x- [HD-RD0035] 8mm Smooth Rod, 315mm
3x- [HD-BT0039] M3x12 Socket Head Cap Screw
26x- [HD-BT0128] M3x6 Flat-Head Socket Cap Screw
6x- [HD-WA0038] M3 washer black oxide
2x- [HD-BT0211] M3x8 Blue Stainless SHCS
1x- [HD-BT0210] M3x30 Blue Stainless SHCS
2x- [HD-BT0206] M3x25 FHCS
1x- [HD-BT0204] M3x22 FHCS
2x- [HD-BL0033] GT2 Timing Belt
2x- [PP-GP0307] Belt Tensioning Collar
1x- [PP-GP0333] Belt Tensioner Post

Tools Required:
Cutters
Needle nose pliers
Phillips screwdriver
508C Sonic Tension Meter
2.5 mm hex driver
2.0 mm hex driver
1.5 mm hex driver
3in-lbs torque driver
5in-lbs torque driver

Hardware required for Final Mechanical Assembly
AS-PR0101 Mini 2 Final Frame Assembly
AS-PR0099 Z-Axis Left Assembly
AS-PR0089 Z-Axis Right Assembly
AS-PR0086 X-Carriage Assembly
AS-TH0066 Titan Aero Assembly,Mini 2
AS-PR0107 Spool Arm Assembly, Mini 2
AS-EL0002 Mini 2 LCD Assembly
PP-GP0320 X-Carriage Cap, Mini 2

2 Install Z-Left Assembly to Frame Assembly

Place the Z Axis left assembly into the frame assembly

Secure the Z Lower left of the Z Axis left assembly to the frame assembly with four M3 x 6 mm flat-head socket cap screws using a 2.0 mm hex driver, torque to 5 in*lbs

Secure the Z Upper Left of the Z Axis left assembly to the frame assembly with six M3 x 6 mm flat-head socket cap screws using a 2.0 mm hex driver, torque to 5 in*lbs

Run the end of the X Harness with the ferrite through the Upper Strain Relief

Attach the X/Extruder Cable harness to the cable chain mount on the Upper Strain Relief

Ensure the Z-Axis Smooth Rods are not making contact with the Z-Motor, this can cause unwanted noise/vibration, there should be a 2-3mm gap between the motor housing and the bottom of the smooth rods.

Torque the lower smooth rod set screw to 3in*lbs as pictured.

Torque the upper smooth rod set screw to 3in*lbs as pictured.

Place Z-Axis Left into frame
Install 4x M3x6 FHCS
Torque fasteners to 5in*lbs
Install 6x M3x6 FHCS
Torque fasteners to 5in*lbs
Pass Cable ferrite through Upper Strain Relief
Connect the cable chain to the mount attached to Upper Strain Relief
Torque lower smooth rod set screw to 3in*lbs
Torque upper smooth rod set screw to 3in*lbs

3 Install Z-Right Assembly to Frame Assembly

Place the Z Axis right assembly into the frame assembly

Secure the Z Lower right of the Z Axis right assembly to the frame assembly with four M3 x 6 mm flat-head socket cap screws using a 2.0 mm hex driver, torque to 5 in*lbs

Secure the Z Upper right of the Z Axis right assembly to the frame assembly with six M3 x 6 mm flat-head socket cap screws using a 2.0 mm hex driver, torque to 5 in*lbs

Ensure the Z-Axis Smooth Rods are not making contact with the Z-Motor, this can cause unwanted noise/vibration, there should be a 2-3mm gap between the motor housing and the bottom of the smooth rods.

Torque the lower smooth rod set screw on the Z-Lower to 3in*lbs as pictured

Torque the upper smooth rod set screw on the Z-Upper to 3in*lbs as pictured.

Place the Z Axis right assembly into the frame assembly
Install 4x M3x6 FHCS
Torque to 5in*lbs
Install 6x M3x6 FHCS
Torque fasteners to 5in*lbs
Torque lower smooth rod set screw to 3in*lbs
Torque upper smooth rod set screw to 3in*lbs

4 Connecting Z-Motors

Completely remove the Z-Right motor housing screw below the connector using a P2 Phillips screwdriver

Insert the right motor's housing screw through the ring terminal of the Z-Right Motor cable, reinstall the housing screw into the Z right motor capturing the ring terminal.
Ensure the screw becomes recessed and tight.
Connect the JST connector to the Z-Right Motor

Completely remove the Z-Left motor housing screw below the connector using a P2 Phillips screwdriver

Insert the left motor's housing screw through the ring terminal of the Z-Left Motor cable, reinstall the housing screw into the Z-Left motor, capturing the ring terminal.
Ensure the screw becomes recessed and tight.
Connect the JST connector to the Z-Left Motor

Remove Phillips head screw below the connector
Attach terminal ring to screw and reinstall
Connect JST connector to motor
Remove Phillips head screw below the connector
Attach terminal ring to screw and reinstall
Connect JST connector to motor

5 Tension Z-Belts

On the X-End Idler, loosen the upper Z-Belt Clamp using a 1.5mm Hex driver.
Grip the end of the belt above the X-End Idler and twist to apply tension to the Z-Belt.
Tighten the two M2x6 SHCS on the upper Z-Belt Clamp to secure the Z-Belt.

Use the 508C Sonic Tension Meter to ensure the belt is tensioned sufficiently.
For complete instructions regarding the 508C Sonic Tension Meter use with Mini 2, see THIS OHAI
Acceptable tension for the Z-Belts is 35-45N For proper measurement results, obtain measurements with the Z-axis near mid travel, ensuring the section of belt being measured is not contacting printed parts; this will provide incorrect tension readings.
Setting number 3 on your 508C Meter is set-up with proper parameters for the Z-axis, if unsure contact your line lead, supervisor, or MER Technician.

Slide the Belt Tensioning Collar [PP-GP0307] down over the end of the belt to capture the slack. Push it as close to the X-End Idler printed part as possible.
Trim the excess belt straight with the teeth of the belt, leaving ~5mm above the belt tensioning collar.

Repeat this process on the X-End Motor side;
Grip the bottom of the X-End Motor printed part and lift until the upper Z-Belt Clamp is visible through the cut-out in the left frame plate.
Loosen the two M2x6 SHCS securing the upper Z-Belt Clamp until the belt is able to move.
Grip the end of the belt on top of the X-End Motor printed part and twist to apply tension to the Z-Belt.
Tighten the two M2x6 SHCS on the upper Z-Belt Clamp to secure the Z-Belt.

Slide the Belt Tensioning Collar [PP-GP0307] down over the end of the belt to capture the slack. Push it as close to the X-End Motor printed part as possible.
Trim the excess belt straight with the teeth of the belt, leaving ~5mm above the belt tensioning collar.

Use the 508C Sonic Tension Meter to ensure the belt is tensioned sufficiently.
Acceptable tension for the Z-Belts is 35-45N. It is best to set the belt towards the top of the range, because they will settle to a lower tension after burn-in. For proper measurement results, obtain measurements with the Z-axis near mid travel, ensuring the section of belt being measured is not contacting printed parts; this will provide incorrect tension readings.
Setting number 3 on your 508C Meter is set-up with proper parameters for the Z-axis, if unsure contact your line lead, supervisor, or MER Technician.

Both Z-Belts should be as close to each other in tension as possible.
Torque Z-Belt Clamp fasteners to 2in*lbs

Loosen both screws securing upper Z-Belt Clamp
Grip the end of the belt above the X-End Idler
Twist with pliers to apply tension, tighten Z-Belt Clamp
Slide Belt Tensioning Collar down over the end of the belt
Grip both sides of belt exiting the tensioning collar to help slide more easily
Belt tensioning collar in place over X-End Idler
Trim 4 teeth and store excess belt in collar
Lift the X-End Motor until upper Z-Belt clamp is visible through slot in left frame plate
Loosen both screws securing the upper Z-Belt clamp
Grip the end of the belt above the X-End Motor
Twist with pliers to apply tension, tighten Z-Belt Clamp
Slide Belt Tensioning Collar down over the end of the belt
Belt tensioning collar in place over X-End Motor, trim 4 teeth and store excess belt through collar

6 Install Y-Axis Drive Belt

Flip the assembly upside down so that it rests on the top frame plate with the Y-Idler to your right.

Cut the Timing Belt [HD-BL0033] at an angle to assist feeding through the Y-Idler.

Loop the belt around the left belt mount post as pictured.

Run the timing belt with the teeth on the inside around the timing pulley, then run the timing belt around the idler bearings and back to the belt mount

Loop the belt around the right belt mount post

Tighten the left M3x12 SHCS to firmly hold the belt.

Grab the loose end of belt (on the right) with a pair of needle nose pliers and pull the belt tight, tighten the right side of the Belt clamp

Use setting number 2 on the 508C Sonic Tension Meter to check the tension in the belt (see OHAI) When measuring the mini 2 belt tensions on the X and Y, push the carriages to the idler side.

The tension should be between 23-27 Newtons. It is best to set the belt towards the top of the range, because they will settle to a lower tension after butn-in.

Trim the excess timing belt, leaving about 20mm on each side.

Flip the assembly upside down
Cut a belt at an angle
Loop the belt around the left belt mount post
Belt around Y-Motor Pulley
Belt routed thought Y-Idler
Wrap around right belt mount post
Tighten left M3x12 SHCS to secure the belt
Grab the belt exiting near the right belt mount post
Twist to apply tension and tighten right M3x12 SHCS
Trim excess belt

7 Install X-Axis Carriage Assembly

Flip the assembly back upright with the back of the machine facing you.

Use a 8mm part reaming tool to ream the smooth rod holes of the X-End Idler.

Push both Left & Right X-Ends down against the Z-Lowers so that they are level with each other.

Slide the two smooth rods through the X End idler assembly and the X carriage assembly as pictured

Insert the ends of the Smooth Rods into the X-End Motor assembly
It is important not to push too far as too much distance between the X-Ends will cause the Z-Axis to bind at the top. Make sure the X-Ends remain relaxed with no outward tension from the Smooth Rods. The ends of the smooth rods should protrude an even distance from the right side of the X-End Idler printed part.

Tighten the set screws already installed in the rear of the X-End Idler; torque to 3in*lbs

Using a 2mm Hex Driver, remove the four M3x8 BHCS securing the X-Bearing Holder to the X-Carriage, slide the X-Bearing Holder to your left on the smooth rod.
Using an eyedropper, apply a small amount of Loctite® 425™ to the now exposed M3 inserts on the back of the X-Carriage.
Re-install all four of the M3x8 BHCS with washers [HD-BT0137] & [HD-WA0038]
Torque all of these fasteners to 3in*lbs

Remove the zip tie from the end of the cable chain.
Remove the cable chain mount from the cable chain and attach to the X-Carriage as pictured using two M3x6 FHCS [HD-BT0128]
Re-attach the cable chain to the mount as pictured.

  • Loctite® is a registered trademark of Henkel Adhesive Technologies
Machine upright, back facing you
Ream smooth rod holes using 8mm part reamer
Push both ends of axis to bottom of travel
Insert two smooth rods about half way
Slide on the X-Carriage Assembly
Insert smooth rod ends into X-End Motor printed part
Torque smooth rod set screws to 3in*lbs
Remove these screws
Slide X-Bearing Holder to the side
Apply thread lock
Re-install M3x8 BHCS with washers
Torque to 3in*lbs
Cut off the zip tie
Remove the cable chain mount
Attach cable chain mount to X-Carriage as shown using two M3x6 FHCS
Connect the cable chain to the cable chain mount

8 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.

X belt in place for carriage drag check
Belt though the frame and loop created for force gauge hook
Checking the carriage drag

9 Install X-Axis Drive Belt

Cut a Timing Belt [HD-BL0033] straight with the teeth of the belt to make an open belt

Grabbing the bottom of the X-Axis, lift the Z-Axis so that the X-Motor pulley can be seen through the cut-out in the left frame plate.

Beginning from the left with the teeth of the belt facing up, feed the drive belt underneath the X-Motor pulley.
Continue back over the X-Motor pulley, back through the X-End Motor printed part.

Slide one Belt Tensioning Collar [PP-GP0307] onto the end of the belt with the narrow end facing the X-End Motor, and the second slack retaining slot facing down.
Fold the belt 40mm from the end so that the teeth of the belt are together.
Slide the Belt Tensioning Collar [PP-GP0307] down over both belt halves, forming a loop at the end.
(both ends of belt will pass through the larger slot of the collar)
It is often helpful to grip the end of the belt at the narrow end of the tensioning collar just after the end is through to slide the Belt Tensioning Collar on further.
Slide the looped end of the belt over the X-Belt Mount post on your right (X-End Motor side)
Slide the Belt Tensioning Collar [PP-GP0307] so that its left edge is 10mm from the right edge of the X-Belt Mount post.
Tuck the belt slack into the second slot on the collar.

With the other end of the belt, begin by passing the belt to your left, underneath the X-End Idler bearings; teeth facing up.
Continue up and around the X-Idler bearings, passing back through the X-End Idler printed part above the bearings.
Make sure there are no twists in the belt.

Slide one Belt Tensioning Collar [PP-GP0307] onto the end of the belt with the narrow end facing the X-End Idler.
Fold the belt down and around the X-Belt Mount post on your left (X-End Idler side) and pulling to your left make a loop.
Grab the bottom side of the belt just to the left of the X-Belt Mount post and leverage your hand to the right to tension the belt.
With another pair of pliers, grip both halves of the belt just to the left of the pliers in your right hand.
Slide the Belt Tensioning Collar [PP-GP0307] over the end of the belt, towards the X-Carriage.
It is often helpful to grip the end of the belt at the narrow end of the tensioning collar just after the end is through to slide the Belt Tensioning Collar on further.
Slide the Belt Tensioning Collar [PP-GP0307] until its right edge is 10mm from the left edge of the X-Belt Mount post.

Trim excess belt to the left of the tensioning collar straight with the teeth of the belt, leaving ~15mm of excess.

Use setting number 2 on the 508C Sonic Tension Meter to ensure the belt is tensioned sufficiently.
Acceptable tension for the X-Belt is 23-40N, refer to the 508C Sonic Tension Meter OHAI-kit. It is best to set the belt towards the top of the range, because they will settle to a lower tension after burn-in.

Install the X-Belt Tensioner Post [PP-GP0333] between the posts of the X-Belt Mount, oriented as pictured, using one M3x22 FHCS [HD-BT0204]
Torque to 3in*lbs

Cut a belt straight with the teeth of the belt
Route the belt from inside of the machine, teeth facing up, underneath the X-Motor Pulley
Continue back over the X-Motor pulley, back through the X-End Motor printed part
Slide on one belt tensioning collar
Fold the belt about 40mm from the end as shown
Slide the belt tensioning collar into place to form a loop at the end of the belt
Place the loop on the right belt mount post as shown, tuck in belt slack
Route belt through X-End Idler below the bearings
Loop back over the bearings and back through the printed part
Slide on a belt tensioning collar, narrow end facing the X-End Idler
Loop the belt down around the left belt mount post as pictured, grab the end, nearest the post with a pair of pliers
Lever your hand to the right to apply tension to the belt
Grab both sides with another pair of pliers
Slide the belt tensioning collar into place as shown, tuck excess belt into second slot
Install X-Belt Tensioner post
X-Belt Tensioner Post installed

10 Install the Extruder Assembly & X-Carriage Cap

Line up the extruder [AS-TH0066] with the X-Carriage
First secure from the back using one M3x30 Blue SHCS with washer [HD-WA0038] through the lower open hole in the X-Belt Mount.
Then secure from above using two M3x8 Blue SHCS [HD-BT0211] with washers [HD-WA0038]
Connect the extruder to the extruder harness as pictured; first routing the cables down through the slot in the top of the X-Carriage before wrapping around and back up to meet connectors.
Slide the cable pathway of the X-Carriage Cap [PP-GP0320] over the exposed wiring of the toolhead and make sure it rests atop the X-Carriage without pinching any wires.
Secure the X-Carriage Cap [PP-GP0320] using 3x M3x12 SHCS [HD-BT0039] with washers [HD-WA0038]
Torque until the screw heads are flush with the top of the X-Carriage Cap.

Line up the extruder assembly as shown, secure with M3x30 SHCS BLUE with washer from the back
Extruder secured from rear
Secure from above with M3x8 SHCS BLUE with washer
Secure with another M3x8 SHCS BLUE with washer
Torque to 5in*lbs
Torque to 5in*lbs
Torque to 5in*lbs
Route cable first down through slot in X-Carriage
And then back up to meet the extruder side harness
X-Carriage cap in place
Secure with M3x12 SHCS with washers, tighten until the screw head is flush with the top of the X-Carriage Cap

11 Install Spool Arm

Install the Spool Arm Assembly [AS-PR0107] to the four open holes in the top of the right frame plate using 4x M3x6 FHCS [HD-BT0128]
Torque to 5in*lbs

Fasten using four M3x6 FHCS; torque to 5in*lbs
Done! Take me home