KUKA KR CYBERTECH nano-2 maintenance troubleshooting

KUKA KR CYBERTECH nano-2 maintenance troubleshooting

KUKA KR CYBERTECH nano-2 is a six axis articulated robot series launched by KUKA for compact applications, covering three main models: KR 6 R1840-2, KR 8 R1640-2, and KR 10 R1440-2. They are usually paired with KR C5 micro or KR C5 S controllers, with a protection level of IP65, wrist part up to IP67, repeat positioning accuracy of about ± 0.04 mm, body weight of about 153 kg to 162 kg, and maximum arm span from 1440 mm to 1840 mm. This series is suitable for handling, assembly, processing, gluing, testing and other scenarios, with a compact structure and good dynamic performance, but with small maintenance windows, precise cable and toothed belt layout, and high requirements for maintenance standardization. Below, we will discuss several aspects including stopping distance, common faults, planned maintenance, gear belt replacement, oil change, cable group lubrication, electrical interfaces, and installation and transportation.

First, consider safety and stopping distance

The danger zone of KR CYBERTECH nano-2 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 under KR C5 micro controller as an example, the stopping distance of A1 for KR 6 R1840-2 is about 20.77 °, A2 is about 19.80 °, A3 is about 14.10 °, corresponding to stopping times of about 0.34 s, 0.23 s, and 0.10 s; The A1 of KR 8 R1640-2 is about 19.05 °, A2 is about 17.00 °, A3 is about 11.90 °, and the time is about 0.21 s, 0.21 s, 0.09 s; The A1 of KR 10 R1440-2 is about 16.12 °, A2 is about 13.14 °, A3 is about 12.41 °, and the time is about 0.19 s, 0.16 s, and 0.09 s. If the KR C5 S controller is used, the STOP 0 data will be larger: A1 of KR 6 R1840-2 is about 31.54 °, A2 is about 29.74 °, A3 is about 27.33 °, and the time is about 0.42 s, 0.34 s, 0.16 s; The A1 of KR 8 R1640-2 is about 23.26 °, A2 is about 25.29 °, A3 is about 23.50 °, and the time is about 0.26 s, 0.35 s, 0.14 s; The A1 of KR 10 R1440-2 is about 24.11 °, A2 is about 22.20 °, A3 is about 26.97 °, and the time is about 0.30 s, 0.25 s, 0.18 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.

A5 toothed belt slipping, noise or positioning error

Performance: A5 movement has abnormal noise, increased reverse clearance, and frequency deviation.

Reason: Aging of the toothed belt, insufficient tension, poor engagement of the pulley, and loose adjustment screws.

Solution: After replacing the A5 toothed belt, measure with a frequency meter. The target frequency is 180 ± 5 Hz. When adjusting, first pre tighten the right pulley, then tighten the 2 M3x6-10.9-A2K TORX round head screws, and the final torque should be executed according to the appendix. Note that the toothed belt must mesh correctly and not tilt; There should be no foreign objects between the toothed belt and the pulley.

Gear oil leakage or abnormal oil level

Performance: There are oil stains near A1, A2, and A3, and the temperature is too high during operation.