KUKA KR 300 R2700-2 C-F maintenance troubleshooting

KUKA KR 300 R2700-2 C-F maintenance troubleshooting

KUKA KR 300 R2700-2 C-F is a high load six axis articulated arm robot with a rated load of 300 kg, a maximum load of 366 kg, a maximum arm span of 2671 mm, a body weight of approximately 1105 kg, a workspace of approximately 51.8 m ³, a repeat positioning accuracy of approximately ± 0.05 mm, and a protection level of IP65/IP67. It is usually paired with KR C5 M6/M7 or KR C4 controllers. Its installation method is mainly ceiling mounted, and the cast version also comes with positive pressure inside the arm, special paint, dust and coolant resistance design. For on-site engineers, the real tricky problem is often not "replacing one part", but how to determine the root cause of the fault without increasing downtime, and complete the replacement, calibration, and testing according to specifications. Below, we will discuss troubleshooting logic, planned maintenance, oil change, balance cylinder, motor and connecting shaft, and zero point calibration.

First, check the safety and shutdown distance

The danger zone of this model is composed of both workspace and stopping distance. The stopping distance is not a fixed value, it is affected by program magnification, load, extension distance, and brake wear. Taking STOP 0 as an example, the stopping distance of A1 is about 32.24 °, A2 is about 14.85 °, and A3 is about 17.46 °; The corresponding stop times are approximately 0.67 s, 0.38 s, and 0.38 s. STOP 1 varies with program magnification and mass, and the corresponding curve needs to be checked. If it is found on site that the robot's sliding after braking has significantly increased, there is abnormal braking noise, and there is repeated positioning drift, the first reaction should not be to change the program, but to check the brake wear and stopping distance. It is recommended to retest the stopping distance at least once a year, especially under frequent triggering of STOP 0, high cycle, and high load conditions.

Strict habits must be formed for safe operation: switch T1 before entering the danger zone, press emergency stop, cut off the main switch and lock it; If it is necessary to debug in the powered on state, it can only run at low speed T1 and ensure emergency stop at any time. After the robot loses power, the power components may still be charged for a short period of time. Wait for at least 5 minutes and verify the power. The motor and brake will generate electromagnetic fields, and personnel wearing active implants such as pacemakers should maintain a distance of at least 300 mm. The surface temperature of the motor is high, and protective gloves must be worn when replacing or inspecting it. When it comes to electrical operations, strictly follow the five safety rules: power off, prevent accidental restart, confirm no power, ground short circuit, and block adjacent live parts; After the work is completed, restore in reverse order.

Common faults and troubleshooting ideas

The stopping distance increases or the braking is abnormal

Performance: Stop position deviation, increased collision risk, and abnormal braking sound in automatic mode.

Reason: Brake wear, incorrect input of load data, high program magnification, external axis stacking motion.

Processing: Verify the load data in the controller, including mass, center of gravity Lx/Ly/Lz, moment of inertia Ix/Iy/Iz, and A/B/C directions; Verify with KUKA Load; Check the brake system; Retest the stopping distance. If there is a change in load or supplementary load, it must be re inputted, not based solely on experience.

Low pressure or abnormal operation of the balance cylinder

Performance: Insufficient A2 axis support force, operational shaking, abnormal noise from the balance cylinder, and pressure gauge reading below requirements.

Reason: Nitrogen leakage, hydraulic oil leakage, aging seal, long-term lack of inspection.

Solution: Manually move A2 to -90 °, wait for 1 minute, emergency stop, connect pressure gauge, wait for 3 minutes, and read the pressure. The minimum pressure at 20 ° C is 244.8 bar. If the value is lower than this or there is a deviation in the application, the balance cylinder must be replaced. The balance cylinder weighs about 40 kg and is under pressure. Before operation, it must be depressurized to zero. Two cranes should be used in conjunction, and attention should be paid to the thrust ring and spacer ring during disassembly and assembly. Microlube GL 261 should be applied.

Gearbox oil leakage or abnormal oil level

Performance: There are oil stains near A1, A2, A3, A4, A5/A6, and metal shavings are attached to the magnetic plug. The temperature is too high during operation.

Reason: seal aging, screw plug not tightened according to torque, incorrect oil quantity, installation angle leading to incomplete oil discharge.

Solution: Replace the gear oil according to the shaft. The recommended oil is Optigear Synt. ALR 150. Initial filling amount: A1 is about 8.30 L, A2 is about 2.10 L, A3 is about 1.40 L, A4 is about 2.10 L, A5/A6 is about 1.40 L (ZH210/ZH210F) or 1.90 L (ZH300/ZH300F). Oil discharge must be carried out at operating temperature and the discharge volume measured. If the discharge volume is less than 70% of the specified amount, it should be rinsed once; If it is less than 50%, rinse twice. The filling amount shall be based on the actual discharge amount. Be aware that the oil chamber may be under pressure, and release the pressure before opening the drain plug. The torque of M18x1.5 magnetic plug is about 20 Nm, A4 is 40 Nm, and A1 union nut is 45 Nm.