How to Install the NexBot Robotics 721-007 Timing Belt

Related Products

Tools Required

• Safety glasses
• Lockout/Tagout kit
• Metric hex key set
• Socket wrench set
• Calibrated torque wrench (5-50 Nm range)
• Belt tension gauge (sonic or force-deflection type)
• Lint-free cloths
• Isopropyl alcohol

Article

This article provides detailed instructions for replacing the NexBot Robotics 721-007 Timing Belt (HTD 5M, 15mm Width). This component is critical for the precise power transmission in the J2, J4, and J5 joints of several NexBot robot models. Proper installation and tensioning are essential to maintain the robot's operational repeatability and prevent premature wear or positioning errors.

WARNING: This procedure involves accessing internal robot components. All work must be performed by qualified technicians who have read and understood the robot's specific maintenance manual. Failure to follow safety procedures can result in equipment damage or serious personal injury.

Prerequisites

Before beginning the installation, ensure you have the following:

• Safety Equipment: Safety glasses, appropriate gloves, and a Lockout/Tagout (LOTO) kit.
• Parts: One new NXB-GEN-721-007 Timing Belt.
• Tools:
• Metric hex key set
• Socket wrench set
• Calibrated torque wrench (5-50 Nm range)
• Belt tension gauge (sonic or force-deflection type)
• Lint-free cloths
• Isopropyl alcohol
• Documentation: The specific maintenance manual for the robot model you are servicing.

Step-by-Step Instructions

1. Safety and Preparation

1. Move the robot to a safe, designated maintenance position. This is typically a folded or zero position.
2. Power down the robot controller following the standard shutdown procedure.
3. Perform a full Lockout/Tagout (LOTO) procedure on the main electrical disconnect for the robot controller. Verify that all stored energy (electrical, pneumatic, hydraulic) has been dissipated.

2. Accessing the Joint

1. Identify the joint requiring the belt replacement (J2, J4, or J5).
2. Carefully remove the access covers for the identified joint. This typically involves unfastening several hex bolts. Keep all fasteners organized for reassembly.
3. Once the cover is removed, you will see the drive motor, pulleys, and the old timing belt.

3. Releasing Belt Tension and Removal

1. Locate the belt tensioning mechanism. This is usually an idler pulley or an adjustable motor mount.
2. Loosen the locking bolts on the tensioner just enough to allow it to move freely.
3. Release the tension on the belt. Do not remove the tensioning hardware completely.
4. Once slack, carefully slide the old timing belt off the drive and driven pulleys.
5. Inspect the old belt for signs of unusual wear, such as fraying, cracked teeth, or delamination, which could indicate pulley misalignment or other issues.

4. Inspection and Cleaning

1. With the belt removed, inspect the teeth of both the drive and driven pulleys for any signs of wear, damage, or debris.
2. Rotate the pulleys by hand to ensure the bearings are smooth and free of binding or excessive play.
3. Clean the pulleys using a lint-free cloth and isopropyl alcohol to remove any grease, oil, or debris. Ensure the pulleys are completely dry before installing the new belt.

5. Installing the New Belt

1. Unpack the new NXB-GEN-721-007 Timing Belt. Do not crimp, bend sharply, or use tools to pry the belt onto the pulleys, as this can damage the internal fiberglass reinforcement cords.
2. Route the new belt around the pulleys, ensuring the teeth of the belt properly engage with the grooves of both pulleys.
3. Confirm the belt is centered on the pulleys and is not rubbing against any flanges or housing components.

6. Tensioning the New Belt

NOTE: Correct belt tension is critical for performance and longevity. The values provided below are examples. Always refer to the specific robot's maintenance manual for the precise tensioning specification and procedure.

1. Apply tension to the belt using the adjustment mechanism. The belt should be taut but not overly tight.
2. Use a belt tension gauge to measure the tension. For a sonic tension gauge, a typical target frequency might be between 110-130 Hz. For a force-deflection gauge, follow the procedure in the manual.
3. Once the correct tension is achieved, tighten the tensioner locking bolts to the manufacturer's specified torque value (e.g., 25 Nm).
4. Re-verify the tension after tightening the locking bolts to ensure it has not changed.

7. Reassembly

1. Rotate the joint mechanism by hand through its full range of motion to ensure the new belt tracks correctly and does not bind or slip.
2. Reinstall all joint access covers, ensuring any gaskets or seals are properly seated.
3. Tighten the cover fasteners to their specified torque values.

Verification

1. Remove the LOTO device and restore power to the robot controller following the standard startup procedure.
2. Clear any errors on the teach pendant that may have occurred during the power-down.
3. Perform a mastering or calibration procedure for the serviced joint as specified in the robot's programming manual. This is essential to restore positional accuracy.
4. Run the robot at a slow speed (10-20%) through a test program that exercises the serviced joint's full range of motion.
5. Listen for any unusual noises, such as whining or clicking, which could indicate improper tension or alignment.
6. If the robot operates smoothly, gradually increase the speed to 100% and run the test cycle for several minutes to confirm the repair is successful and stable.
7. Document the maintenance activity in the robot's service log.

Keywords