Technical Bulletin: Joint Overhaul Procedure for R-50/R-100 Robots using NXB-KIT-762-004

Related Products

Tools Required

• Calibrated torque wrench
• Bearing puller set
• Seal installation tool kit
• Metric socket and wrench set
• Hex key set
• Clean lint-free cloths
• Approved robot lubricant
• Personal Protective Equipment (PPE)
• Robot arm support/bracing equipment

Article

Overview

This document outlines the recommended procedures for utilizing the NexBot Robotics 762-004 Joint Overhaul Maintenance Kit (SKU: NXB-KIT-762-004) to perform scheduled maintenance on the major axes of NexBot R-50 and R-100 series articulated robots. Adherence to these guidelines is critical for restoring the robot's original performance specifications, maintaining positioning accuracy, and preventing unplanned downtime. The recommended service interval for this procedure is every 8,000 operating hours or as indicated by robot performance diagnostics.

Scope

This bulletin applies to all robot models within the NexBot R-50 and R-100 series. The procedures herein are specific to the installation of components included in the NXB-KIT-762-004. Always consult the specific service manual for your robot model for detailed diagrams, torque specifications, and safety procedures.

Kit Contents and Purpose

The NXB-KIT-762-004 includes all necessary OEM components for a complete joint overhaul:

• Harmonic Drive Wave Generator Plugs: Essential for sealing and protecting the high-precision gear reduction system.
• Crossed Roller Bearings (Set of 3): High-rigidity bearings that manage complex loads on the joint, critical for robot accuracy and repeatability.
• High-Pressure Shaft Seals (Set of 3): Prevents lubricant leakage and contamination of internal joint components.
• Internal Wiring Harness Fasteners: Secures internal cabling, preventing chafing and electrical faults after reassembly.
• Joint Housing O-Ring Kit: Provides static sealing for the main joint housing assembly against environmental ingress and lubricant loss.
• Axis Lubrication Port Fittings: Replacement fittings to ensure a clean, reliable connection for future lubrication tasks.

Pre-Procedure Recommendations

Safety

• LOCKOUT/TAGOUT (LOTO): Before beginning any work, ensure the robot controller and all related power sources are de-energized and locked out according to your facility's safety protocols.
• Residual Energy: Verify that all pneumatic, hydraulic, and electrical energy has been dissipated.
• Mechanical Support: Securely brace the robot arm to prevent unexpected movement or collapse during disassembly.
• Personal Protective Equipment (PPE): Wear appropriate safety glasses, gloves, and steel-toed footwear.

Preparation

• Clean Environment: Perform the overhaul in a clean, dry, and well-lit area to prevent contamination of sensitive components.
• Review Documentation: Have the official service manual for your specific robot model readily available.
• Organize Parts: Lay out all contents of the NXB-KIT-762-004 on a clean surface. Verify all parts are present and free of damage before starting.

Overhaul Procedure

Step 1: Disassembly

1. Remove Covers: Carefully remove the cosmetic and protective covers for the target joint axis.
2. Disconnect Services: Disconnect any electrical connectors and pneumatic lines routed through the joint. Label all connections to ensure correct reassembly.
3. Drain Lubricant: Place a suitable container beneath the joint and remove the drain plug. Allow the old lubricant to drain completely.
4. Joint Separation: Following the procedure in the service manual, unfasten the main housing bolts in the specified sequence to release pressure evenly. Carefully separate the joint housing. This may require specialized lifting or support equipment.

Step 2: Component Replacement

1. Bearing and Seal Removal: Using a bearing puller and seal removal tools, carefully extract the old crossed roller bearings and high-pressure shaft seals. Avoid scratching or damaging the housing surfaces.
2. Cleaning and Inspection: Thoroughly clean all housing components with an approved industrial solvent. Inspect all surfaces, especially bearing seats and sealing surfaces, for signs of wear, galling, or damage. Replace the entire joint assembly if significant damage is found.
3. Seal Installation: Lubricate the new High-Pressure Shaft Seals with the recommended grease. Using a seal installation tool, press the new seals into place until they are fully and evenly seated. Ensure the seal orientation is correct as per the service manual diagram.
4. Bearing Installation: Install the new Crossed Roller Bearings. These are high-precision components that must be handled with care. Ensure they are correctly oriented and pressed squarely into their seats. Follow the service manual for any pre-loading requirements.
5. O-Ring Installation: Remove the old O-rings from the joint housing. Clean the O-ring grooves. Lightly lubricate the new O-rings from the kit with the appropriate grease and install them carefully, ensuring they are not twisted or pinched.

Step 3: Reassembly

1. Join Housing: Carefully bring the two halves of the joint housing together, ensuring all internal components and wiring are correctly positioned. Ensure dowel pins are aligned.
2. Fastening: Install the main housing bolts. Using a calibrated torque wrench, tighten the bolts in the crisscross sequence specified in the service manual to the exact torque value. This is critical for proper bearing preload and sealing.
3. Replace Fittings: Replace the old lubrication port fittings with the new ones provided in the kit.
4. Reconnect Services: Reconnect all electrical and pneumatic lines. Replace any Internal Wiring Harness Fasteners that were removed.
5. Refill Lubricant: Fill the joint with the specified type and quantity of lubricant.
6. Reinstall Covers: Reinstall all protective covers.

Post-Procedure Verification

1. Power On: Remove LOTO and power on the robot controller.
2. Check for Errors: Ensure no new error codes are present.
3. Jog Axis: In Teach Pendant mode, jog the serviced axis at a very low speed (1-5%) through its full range of motion. Listen for any unusual noises and watch for any binding or jerky movement.
4. Leak Check: Carefully inspect the joint for any signs of lubricant leakage around the new seals and fittings.
5. Mastering/Calibration: Perform the robot mastering procedure as outlined in the service manual to re-establish the robot's zero position.
6. No-Load Test: Run a simple motion program for 15-30 minutes without any payload to confirm smooth operation and allow the new components to break in.

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