Tools and Materials

• Shop Air (90 PSI or greater)
• Step stool
• Hex keys
• Velocite #6 Oil
• Ballscrew Mount Rebuild Kit
• Rigid coupling with screws
• 8mm thrust bearings (2)
• 8mm radial Bearing
• Belleville washers (2)
• M4x6 brass-tipped set screw
• Nitrile gloves
• On loan from Diabase Engineering:
• Pneumatic Preload Tool
• Torque screwdriver capable of 30 in-lb (3.4 Nm)
• Long 3 mm Hex Bit
• Wooden Support Block approx. 230 mm (9 in)

Process

Disassembly

1. Loosen all the top build enclosure panel mounting screws.
2. Fully remove the leftmost and two rightmost top build enclosure panel mounting screws
3. Slide both top build enclosure panels outward to access the panel surrounding the z-axis motor
4. Remove the three M4 screws securing the upper z-axis bellows to the panel surrounding the z-axis motor and allow the bellows to drop.
5. Unplug the build enclosure LEDs
6. Remove the four M5 screws securing the sheet metal around the z-axis motor
7. To remove the sheet metal, lower the front portion below the frame and carefully maneuver the panel around the wires on the right side of the z-axis motor. You might need to bend the panel slightly to avoid catching on the wires.
8. Place a support block at least 200 millimeters but no more than 230 millimeters between the rear of the arm and the rear of the chip tray. Be sure the support block is resting on the black sheet metal of the chip tray and not the stainless steel shroud.
9. To remove the rigid coupling, the z-axis ballscrew will need to rotate until the rigid coupling mounting screws heads are accessible.
10. While watching the coupling, slowly lower the arm until it is approximately 13 mm (0.5 in) above the block and the screw heads are accessible.
11. Now that the arm is in this position, turn the machine off before putting your fingers near any pinch points.
12. Loosen the upper screw in the rigid coupling.
13. While supporting the arm, loosen the lower screw in the rigid coupling. The ballscrew may drop a few inches before resting on the rear of the chip tray and this is ok.
14. Gently lower the arm until it is resting on the support block.
15. Loosen the M4 set screw in countertorque arm.
16. Lift the z-axis motor off the countertorque block pin.
17. Remove the shaft coupling and set aside.
18. The ballscrew and bearing components require lubricant and should remain free of dust and debris. For this reason, we recommend wearing disposable gloves whenever handling the ballscrew or bearing components, to keep both your hands and the components clean.
19. If the upper end of the ballscrew is still within the ballscrew flange, it will need to be lowered. Carefully grasp it with gloved hands and twist to the left.
20. Remove and set aside the three bearing components on top of the ballscrew, below the ballscrew flange: 
1. Loose thrust bearing race (without text)
2. Bearing cage
3. Tight thrust bearing race (with text).
21. Using a hex key to push from below, remove and set aside the six bearing components from the top of the ballscrew flange
1. Two Belleville washers
2. Tight thrust bearing race (with text)
3. Bearing cage
4. Loose thrust bearing race (without text)
5. Radial bearing. 

Initial Reassembly

1. Open the ballscrew mount rebuild kit and lay out the components on a clean surface. The order in which these bearing components are installed and their orientation does matter, so please take a few extra moments of care for reassembly. 
2. Starting from the left, the thrust bearing that goes below the ballscrew flange on the machine consists of:
1. Tight thrust bearing race (with text)
2. Bearing cage
3. Loose thrust bearing race (without text). 
3. Continuing with the components that will go above the ballscrew flange:
1. Radial bearing
2. Loose thrust bearing race (without text)
3. Bearing cage
4. tight thrust bearing race (with text)
5. Two Belleville washers
6. Rigid coupling.
4. Place a drop of velocite oil on the inner surface of each thrust bearing race.
5. Install the first tight thrust bearing race onto the ballscrew with the text on the flat side facing down. This should be a tight fit, so you may need to gently wiggle the bearing race to get it started. Add the bearing cage and then the loose thrust bearing (that’s the one without the engraved text) with the flat side facing up.
6. Starting from the bottom, the components will be installed in the following order:
1. Tight thrust bearing race (with text)
2. Bearing cage
3. Loose thrust bearing race (without text)
7. Next, we need to raise the ballscrew through the ballscrew flange. To do this, grasp the ballscrew with your gloved hand and twist to the right. 
8. Install the radial bearing. There is a small pocket on the top of the ballscrew flange that retains the radial bearing. You might need to wiggle the ballscrew and bearing slightly to ensure that the bearing is fully seated. 
9. Install the loose thrust bearing race (without text) flat side down, followed by the bearing cage, and then the tight thrust bearing with the text on the flat side facing upward.
10. The Belleville washers go on with the cupped sides facing each other.
11. Slide the rigid coupling onto the top end of the ballscrew with the heads of the screws pointing to the right side of the machine.
12. If the bearings and ballscrew are fully seated, the top and bottom races of the upper and lower thrust bearings should be just flush with the upper and lower faces of the ballscrew flange, respectively.
13. Temporarily tighten the lower screw in the rigid coupling just enough to hold the assembly in place while we prepare for applying the preload and final torque to the ballscrew and bearings.

Preload Z-Axis Ballscrew Bearing

1. Attach the pneumatic preload cylinder to the ballscrew flange with the thumbscrews.
2. Connect the pneumatic preload cylinder valve to shop air and slowly rotate the valve handle toward you.
3. Check the gauge on the regulator and confirm that it reads between 80 and 85 psi (552-586 kPa).
4. From the front of the machine, visually confirm that the pneumatic preload cylinder has extended and is pressing on the top of rigid coupling.
5. With a gloved hand, grasp the ballscrew to prevent it from rotating and loosen the lower screw in the rigid coupling.
6. Make sure that the ballscrew and lower thrust bearing are fully seated in the ballscrew flange and torque the lower rigid coupling screw to 30 in-lb (3.4 Nm)
7. Rotate the valve to the exhaust side and disconnect the pneumatic preload cylinder.

Reinstall Z-Axis Motor

1. With the motor electrical connector pointing toward the left of the machine, slide the motor/countertorque arm assembly into the rigid coupling and onto the countertorque block pin
2. Torque the motor-side coupling screw to 30 in-lb (3.4 Nm)
3. Install set screw in countertorque arm and tighten to about 6 inch-pounds.

Final Reassembly

1. Return the panel around the z-axis motor and align the mounting holes with the tee nuts positioned in the upper frame components.
2. Replace the four M5 screws securing the panel.
3. Take a moment to check the wiring connections for the z-axis motor and the z-axis limit switch are still securely in place.
4. Lift the upper z-axis bellows and secure to the sheet metal panel with the three M4 screws. Be careful to not overtighten.
5. Slide the top build enclosure panels back into place and reinstall the mounting screws.
6. With everything reassembled, you can turn the machine back on and home the z-axis to remove the block.

Repack and Return

Repack the tools on loan from Diabase Engineering in the original packaging and return using the included prepaid shipping label.

As always, please don’t hesitate to contact us if you need any additional support.