Introduction
The ABB IRB 6700 is a robust industrial robot designed for demanding applications. However, like any sophisticated machinery, components like axis motors may eventually require replacement due to wear, electrical faults, or unforeseen incidents. Replacing an axis motor is a critical repair task that restores the robot's operational capability.
This guide provides a structured approach for safely replacing the Axis 1 motor on your IRB 6700. While based on the official ABB product manual (referencing document ID 3HAC044266-001, Revision -), this article aims to offer practical insights and emphasize critical safety considerations.
IMPORTANT:
This procedure requires significant mechanical and electrical expertise. Only personnel trained and authorized by ABB, possessing the necessary skills and understanding of the robot system, should attempt this repair. Improper execution can lead to severe personal injury, equipment damage, and voided warranties.
Safety First: Critical Precautions
Motor replacement involves handling heavy components, interacting with high-voltage systems (potentially with stored energy), and managing potentially hazardous brake releases. Safety is paramount. Before proceeding, ensure you understand and adhere to the following:
Lockout/Tagout (LOTO)
ALWAYS ensure all energy sources (electrical, pneumatic, hydraulic) are completely de-energized and properly locked/tagged out according to your facility's procedures before entering the robot's work envelope or starting any disassembly.
Stored Energy
Be aware of stored electrical energy within the controller (DC link capacitors) even after power down. Allow sufficient discharge time as specified in the main controller manual.
Mechanical Hazards
Releasing motor brakes will cause axes to move due to gravity, potentially leading to crushing or impact injuries. The lower arm (Axis 2/3) poses a significant hazard if not properly secured.
The balancing device contains high-tension springs. Never attempt to disassemble the balancing device itself.
Heavy Components
The Axis 1 motor weighs approximately 21 kg. Always use appropriate lifting accessories and techniques. Ensure lifting equipment is correctly rated and inspected.
Brake Release
Releasing brakes is hazardous. Ensure no personnel are near or beneath the robot arm. Accidental release of the wrong brake or all brakes simultaneously can occur if power is supplied incorrectly for manual release.
Hot Surfaces
Motors and gearboxes can become extremely hot during operation. Allow ample cooling time before touching components to prevent burns.
Electrostatic Discharge (ESD)
Internal electronic components (like the SMB board if handled) are sensitive to ESD. Use appropriate grounding measures (wrist strap connected to the cabinet's ESD point) when handling electronics.
Personal Protective Equipment (PPE)
Always wear appropriate PPE, including safety glasses, gloves, and safety shoes.
Required Tools and Parts (Axis 1)
Before starting, gather all necessary tools, consumables, and the correct replacement motor. Refer to the ABB IRB 6700 Spare Parts list for specific article numbers.
Specialized Tools
- Lifting accessory, motor (e.g., 3HAC14459-1)
- Removal tool M14 (e.g., 3HAC047108-001 - Used to push motor out, if necessary)
- Guide pins, M12x150 (e.g., 3HAC13056-2 - Always use in pairs)
- Bits extender, 300 mm, 1/2" bits (e.g., 3HAC12342-1)
- Leak-down tester (e.g., 3HAC0207-1)
- 24 VDC power supply (for brake release, if needed)
- Rotation tool (e.g., 3HAC7887-1 - for pinion rotation during refit)
- Torque Wrench (calibrated)
Standard Toolkit
- Appropriate sockets/wrenches for motor bolts and cover screws
- Allen keys
Consumables
- Grease (e.g., 3HAB3537-1 for O-rings)
- O-ring, motor cover (e.g., 3HAB3772-111, D=169.5x3)
- O-ring, motor flange (e.g., 3HAB3772-107, D=102x3)
- Cleaning supplies (lint-free cloths, approved solvent)
- Locking liquid (if specified for certain screws, check specific procedure)
Replacement Part
- Axis-1 Motor (Correct P/N for your robot variant)
Step-by-Step Motor Replacement Procedure (Axis 1)
(Refer to Manual pages 387-395 for detailed diagrams)
Preparations
Position & LOTO
Disconnection
Cables & Covers
Removal
Motor Extraction
Installation
Fitting New Motor
Verification
Testing & Calibration
Preparations
• Position the Robot: Jog the robot to the calibration position (All axes at 0°). This often provides the best access and a known starting point.
CRITICAL: Perform full Lockout/Tagout (LOTO) procedure for all energy sources (Electrical, Hydraulic, Pneumatic). Verify zero energy state.
Disconnecting the Motor Cables
• Access the Motor: Carefully unscrew the attachment screws and washers securing the motor cover. Note the orientation of the cover.
• Remove Cover: Remove the motor cover.
• Disconnect Cables: Disconnect the motor cables from the motor terminals. Tip: Label cables clearly before disconnecting if markings are unclear.
• Cable Gland: Remove the cable gland cover. Inspect the gasket; replace if damaged. Tip: Note the orientation of the cable exit hole for correct refitting.
• Pull Cables: Use caution and gently pull the motor cables out from the motor housing.
Removing the Axis-1 Motor
• Prepare Lifting: Apply the motor lifting accessory (e.g., 3HAC14459-1).
Release Brakes (If Necessary): If motor rotation is needed for removal/refitting or if the robot wasn't positioned correctly, you may need to release the Axis 1 brake. Connect the 24 VDC power supply only to the correct R2.MP1 connector pins (+ pin 2, - pin 5). Extreme caution is required.
CAUTION: The motor weighs 21 kg. Ensure the lifting accessory is secure and properly rated.
• Remove Screws: Unscrew the motor attachment screws and washers. Use the bits extender to reach all screws.
• Install Guide Pins: Fit two guide pins (e.g., M12x150) into opposite motor mounting holes. This helps stabilize the motor during removal and prevent damage.
CAUTION: When separating the motor from the gearbox, avoid using excessive force, as this can damage the gears or pinion.
• Use Removal Tool: If needed, use the removal tool (e.g., M14 tool 3HAC047108-001) in the designated holes to gently press the motor away from the gearbox.
• Lift Motor: Use caution and lift the motor straight up/out, ensuring the motor pinion clears the gearbox gear cleanly. Avoid tilting the motor excessively during removal.
• Disconnect Power: Disconnect the 24 VDC power supply if it was used.
• Secure Motor: Place the old motor safely aside.
Refitting the Axis-1 Motor
• Clean Surfaces: Thoroughly clean the mounting surfaces on both the gearbox and the new motor. Remove any old paint, sealant, or contamination. Wipe clean the o-ring groove on the motor.
• Inspect O-rings: Check the condition of the motor flange O-ring (D=102x3). Replace if damaged. Ensure the new o-ring is correctly seated in its groove. Tip: Lubricate the o-ring lightly with approved grease (3HAB3537-1) for easier fitting.
• Prepare New Motor: Remove the protective cover from the new motor, if present.
• Insert Guide Pins: Fit two guide pins into opposite holes on the gearbox mounting flange.
CAUTION: Ensure the motor weighs only 21 kg. Use the lifting accessory.
• Prepare for Alignment: Fit the rotation tool to the motor shaft if fine adjustment is needed during mating.
• Lower Motor: Align the motor using the guide pins. Lower it slowly towards the gearbox.
- Ensure the motor pinion meshes correctly with the gearbox gear. Gentle rotation using the rotation tool might be necessary. Do NOT force the connection.
- Verify the cable exit gland is oriented correctly (refer to notes/photos taken during removal).
• Install Screws: Once mated, fit the attachment screws and washers.
• Remove Guide Pins: Remove the guide pins and install the remaining attachment screws.
• Torque Screws: Tighten the motor screws evenly in a criss-cross pattern to the specified torque: 47 Nm. Use a calibrated torque wrench and the bits extender.
• Leak Test: Perform a leak-down test (See Section 4.2.1, page 174 and details below). This is crucial to ensure gearbox sealing integrity.
• Disconnect Power: Disconnect the 24 VDC power supply if used.
Connecting the Motor Cables
• Insert Cables: Push the motor cables back through the cable gland opening.
• Install Gland Cover: Refit the cable gland cover. Ensure the gasket is correctly positioned and replace it if damaged. Tighten screws appropriately.
• Connect Cables: Connect the motor cables to the correct terminals, matching any labels or markings noted during disassembly. Ensure connections are secure.
• Check O-ring: Check the motor cover O-ring (D=169.5x3). Replace if damaged.
• Prepare Cover: Wipe the O-ring and groove clean. Ensure the O-ring is seated correctly.
• Install Cover: Refit the motor cover and secure it with its screws and washers. Ensure it is tightly sealed.
Post-Replacement Procedures
Leak-Down Test
• Remove Oil Plug: Remove the topmost oil plug on the Axis 1 gearbox.
• Install Tester: Fit the leak-down tester (3HAC0207-1).
• Apply Pressure: Carefully apply compressed air, raising pressure slowly to 0.2 - 0.25 bar (20 - 25 kPa). DO NOT EXCEED 0.25 bar.
• Monitor Pressure: Disconnect air supply and monitor pressure for 8-10 minutes. There should be no significant pressure loss.
• Address Leaks: If a leak is detected (pressure drops), use leak detection spray to pinpoint the source (e.g., motor seals, cover seals) and rectify before proceeding.
• Finish Test: Remove the tester and refit the oil plug (Tightening torque: 24 Nm).
Final Steps
• Remove Tools: Safely remove the motor lifting accessory and any other tools.
• Power Up & Update Counters: Carefully remove LOTO and restore power to the controller first, then the robot. Crucially, the motor replacement requires updating the revolution counters. Navigate to the Calibration menu on the FlexPendant and perform the "Update Revolution Counters" procedure for Axis 1 (refer to Section 5.5, page 542). Failure to do this will result in incorrect positioning.
• Calibration Check: After updating counters, carefully jog Axis 1 and verify that the calibration marks align correctly (Section 5.6, page 544).
• Recalibration: While a revolution counter update is the minimum, replacing a motor often affects the precise calibration. Performing a standard calibration (e.g., using Calibration Pendulum method - Section 5.2, page 538) is highly recommended to ensure accuracy. If the robot utilizes the Absolute Accuracy option, a new Absolute Accuracy calibration is necessary to restore full performance.
DANGER! First Test Run: Before running any programs, perform the first test run with extreme caution, following the safety procedures outlined in Section 1.3.4 (page 44). Stand clear, run at low speed, and verify expected movement.
Adaptation Notes for Other Axes
| Axis | Special Considerations | Motor Weight | Torque | Post-Refit Steps |
|---|---|---|---|---|
| Axis 2 (4.7.2) | Requires draining gearbox oil first. Involves securing the lower arm with a lock screw (M16x120). | 26 kg | 47 Nm | Refill oil, leak test, update counters, calibrate. |
| Axis 3 (4.7.3) | Requires unloading/supporting the upper arm. | 24 kg | 47 Nm | Leak test, update counters, calibrate. |
| Axis 4 (4.7.4) | May not require draining oil if positioned correctly (Axis 3 vertical). | 11 kg | 35 Nm | Leak test, update counters, calibrate. |
| Axis 5 (4.7.5) | Located inside the wrist. Requires specific positioning (Axis 4 +90°, Axis 5 +90°). Involves removing wrist cover/heat shield. | 11 kg | 24 Nm | Leak test, update counters, calibrate. |
| Axis 6 (4.7.6) | Located at the end of the wrist. Often requires Axis 5 at +90° for access. Involves removing motor cover. | Varies (check manual) | 24 Nm | Leak test, update counters, calibrate. |
For each axis, substitute the specific:
- Axis number in the title and text.
- Relevant manual page numbers.
- Specific preparation steps (e.g., draining oil, locking arm).
- Motor weight and required lifting precautions.
- Specific tools (e.g., different removal tools if applicable).
- Correct screw dimensions and tightening torques.
- Post-replacement steps (e.g., refilling oil).
Conclusion
Replacing the Axis 1 motor on an IRB 6700 is a manageable but critical task for qualified personnel. Success hinges on meticulous adherence to safety protocols (especially LOTO and brake management), careful handling of components, correct tool usage, and mandatory post-replacement checks including the leak-down test and revolution counter updates/recalibration.
Always prioritize safety and consult the official ABB documentation or ABB Service if any step is unclear or if unexpected issues arise. Proper execution ensures the robot returns to reliable and accurate operation.
Safety Overview
Key Safety Points:
-
Always perform complete LOTO procedures
-
Be aware of stored energy (mechanical & electrical)
-
Use proper lifting equipment for the 21kg motor
-
Use extreme caution when releasing brakes
-
Always update revolution counters after replacement
Critical Values:
- Axis 1 Motor Weight: 21 kg
- Torque Specification: 47 Nm
- Leak Test Pressure: 0.2-0.25 bar
- Oil Plug Torque: 24 Nm