KUKA KR 20 R1810 HO maintenance troubleshooting

KUKA KR 20 R1810 HO maintenance troubleshooting

KUKA KR 20 R1810 HO belongs to the Hygienic Oil food grade version of the KR CYBERTECH series, mainly targeting food grade areas. It adopts special gear oil, enhanced anti-corrosion design and light gray coating, with a rated load of 20 kg, a maximum load of 23.9 kg, a maximum arm span of 1813 mm, a repeat positioning accuracy of about ± 0.04 mm, a body weight of about 250 kg, a working space of about 23.3 m ³, a protection level of IP65, and a wrist part that can reach IP67. It is usually paired with KR C5 S6/S7 or KR C4 controllers. For on-site engineers, the real tricky problem is not "replacing a component", but how to determine the root cause of the malfunction in a food grade environment and complete the replacement, calibration, and cleaning according to specifications. Below, we will discuss several aspects including stopping distance, common faults, planned maintenance, involute teeth, oil change, cable lubrication, food grade cleaning and PURGE, and installation and transportation.

First, consider safety and stopping distance

The danger zone of KR 20 R1810 HO consists 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, A1 stops at a distance of about 16.27 °, A2 stops at a distance of about 17.61 °, and A3 stops at a distance of about 27.24 °; The corresponding stop times are approximately 0.23 s, 0.19 s, and 0.26 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.

Wear of involute teeth or abnormal motor noise

Performance: A1 to A6 motion jitter, increased reverse clearance, and high motor temperature.

Reason: Insufficient lubrication of the teeth, aging of the O-ring, improper installation of the motor, and long-term high load.

Solution: Check the involute teeth according to the maintenance table. Clean the teeth and check for wear and tear; If the teeth are damaged, the input shaft of the motor or gearbox must be replaced, and the replacement of the gearbox input shaft requires contacting KUKA Service. Apply Microlube GL 261 to the teeth, thin and continuous, about 2 g. Check the O-ring and replace it if it is damaged.

Gear oil leakage or abnormal oil level

Performance: There are oil stains near A1, A2, A3, A4, A5/A6, and the temperature is 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 Cassida Fluid GL150. Initial filling amount: A1 is about 1.20 L, A2 is about 0.80 L, A3 is about 0.32 L, A4 is about 0.32 L, A5/A6 is about 0.37 L. Oil discharge must be carried out at operating temperature and the discharge amount must be 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, M10x1 plug is about 7.5 Nm, and A1 union nut is about 45 Nm.