KUKA KR CYBERTECH-3 maintenance troubleshooting



KUKA KR CYBERTECH-3 maintenance troubleshooting

KUKA KR CYBERTECH-3 is a six axis articulated robot series launched by KUKA for medium to high load applications. The current document covers two models, KR 25 R1840-3 and KR 35 R1840-3. Both have a body weight of approximately 237 kg, a maximum arm span of 1840 mm, a workspace of approximately 24.4 m ³, a repeat positioning accuracy of approximately ± 0.03 mm, a protection level of IP54, and an IP67 wrist section. They are typically paired with KR C5 S6/S7 controllers. KR 25 R1840-3 has a rated load of 25 kg and a maximum load of 38 kg; KR 35 R1840-3 has a rated load of 35 kg and a maximum load of 49 kg. They can be used in scenarios such as handling, assembly, processing, palletizing, and inspection. They have a compact structure and good dynamic performance, but require high installation, cable layout, and planned maintenance. Below, we will discuss several aspects including stopping distance, common faults, planned maintenance, oil change, cable group lubrication, zero point calibration, installation and transportation, and electrical interfaces.

First, consider safety and stopping distance

The danger zone of KR CYBERTECH-3 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, the stopping distance of KR 25 R1840-3 at A1 is about 27.86 °, A2 is about 23.98 °, and A3 is about 35.09 °; The corresponding stop times are approximately 0.25 s, 0.26 s, and 0.26 s. The stopping distance for A1 of KR 35 R1840-3 is about 34.75 °, A2 is about 17.30 °, and A3 is about 34.18 °; The stop time of A1 is about 0.34 seconds. STOP 1 varies with the 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 fault one: abnormal stopping distance and brake wear

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.

For KR 25 R1840-3, the stopping distance and stopping time of A3 are prominent, indicating that the axle has a high braking load during high-speed motion. For KR 35 R1840-3, the stopping distance of A1 and A3 is relatively large, especially at high loads. Therefore, if it is found on site that the A3 has slid longer after braking, priority should be given to checking the A3 motor brake, gearbox, and load data. If the stopping distance of A1 is abnormal, the base fixation, cable dragging, and A1 motor brake should be checked. Abnormal stopping distance is often not a single cause, but the result of the combined effects of mechanical wear, load parameters, and program magnification.

Common Fault 2: Gear Oil Leakage and Oil Change

Performance: There are oil stains near A1, A2, A3, A4, and A5, the temperature is high during operation, and metal shavings are attached to the magnetic plug. 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 maintenance table in the document shows that when KR 25 R1840-3 is replaced with A5 gear oil at 20000 hours or 5 years, the initial filling amount is about 0.15 L; when A4 gear oil is replaced, the initial filling amount is about 0.20 L. Similarly, when KR 35 R1840-3 is replaced with A5 gear oil at 20000 hours or 5 years, the initial filling amount is about 0.15 L and A4 is about 0.20 L. In addition, when it is replaced with A3 at 20000 hours or 5 years, the recommended oil is Optigear Synth. ALR 150. 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 the screw plug shall be executed according to the appendix. The M18x1.5 magnetic screw plug is usually about 20 Nm, and the M10x1 is about 7.5 Nm. After changing the oil, check for leaks and observe abnormalities during T1 operation.

Common fault three: Insufficient lubrication of cable assembly

The maintenance table of KR 35 R1840-3 clearly requires: lubricating cable group A4 for 10000 hours, using Optitemp RB2 for about 0.06 kg; lubricating cable group A1 for 10000 hours, using Optitemp RB2 for about 0.08 kg. The lubrication items for cable groups are not listed in the document of KR 25 R1840-3, but if the base or arm cables are worn, make abnormal noises, or accumulate dust on site, the hoses, cables, and drag chains should still be inspected. Clean the hose and contact surface during processing, apply the approved lubricating grease thinly and evenly, wipe off excess grease after reinstallation, and move the relevant shaft to evenly distribute the grease. Lubricating grease should not be excessive to avoid adsorbing dust. If the hose is damaged, the cable assembly must be replaced.

Common fault four: Mastering loss and zero calibration

Performance: teaching point offset, program unable to reproduce, abnormal axis angle display. Reason: Replacement of motor, manual release of brake, loss of encoder data, collision. The Mastering positions for this series are: A1 0 °, A2-90 °, A3 90 °, A4 0 °, A5 0 °, A6 0 °. Priority should be given to using EMD or a dial gauge for standard Mastering. After replacing the motor, gearbox, toothed belt, connecting shaft or manually moving the brake, it is necessary to re master. If the release device is used to move the motor, the shaft will lose its zero point and must be re Mastered. The accuracy of emergency Mastering is relatively low, and standard methods should be used to recalibrate as soon as possible afterwards.

Common Fault 5: Installation Base and Foundation Load

Performance: Robot shaking during operation, abnormal noise from the feet, and poor repeated positioning. Reason: Insufficient torque of base bolts, cracking of concrete foundation, and failure of chemical anchor bolts. KR CYBERTECH-3 can be installed on a base S310, weighing approximately 25.4 kg, using 4 M20x55-8.8 hex bolts and chemical anchor bolts; It can also be installed using a machine frame, weighing approximately 1.05 kg, using 4 M20x50-8.8 hex bolts. The basic concrete grade shall be at least C20/25. Tighten the base bolts after 100 hours and conduct annual inspections thereafter.

In terms of basic load: KR 25 R1840-3 floor installation Fv normal 4058 N，Fv max 5660 N，Fh normal 2080 N，Fh max 6132 N，Mk normal 3386 Nm，Mk max 9792 Nm，Mr normal 1819 Nm，Mr max 5095 Nm； ceiling installation Fv normal 4367 N，Fv max 5775 N，Fh normal 2259 N，Fh max 6028 N，Mk normal 3808 Nm，Mk max 9921 Nm，Mr normal 1858 Nm，Mr max 5097 Nm； Wall installation Fv normal 4332 N，Fv max 7705 N，Fh normal 1812 N，Fh max 3935 N，Mk normal 3733 Nm，Mk max 9415 Nm，Mr normal 1895 Nm，Mr max 5215 Nm。 KR 35 R1840-3 Floor Installation Fv normal 3822 N，Fv max 5618 N，Fh normal 1780 N，Fh max 6177 N，Mk normal 2837 Nm，Mk max 9855 Nm，Mr normal 1778 Nm，Mr max 5201 Nm； ceiling installation Fv normal 4397 N，Fv max 5833 N，Fh normal 2145 N，Fh max 5976 N，Mk normal 3116 Nm，Mk max 10149 Nm，Mr normal 1854 Nm，Mr max 5197 Nm； Wall installation Fv normal 4337 N，Fv max 8242 N，Fh normal 1488 N，Fh max 4015 N，Mk normal 3637 Nm，Mk max 9420 Nm，Mr normal 1925 Nm，Mr max 5319 Nm。 The maximum load is used for foundation design and must be followed.

Common Fault 6: Connecting Cable and Grounding

Performance: The controller reports motor/data line faults, intermittent shutdowns, and abnormal shielding. Solution: Check motor cables XD20.1... XD20.6/XD10.1/XD10.2 to XD30, and data cables XF21 to XF31. The grounding conductor has a cross-sectional area of 16 mm ², an M8 ring terminal, and an M8 nut torque of approximately 15.0 Nm. The cable length can be selected from 2.7 m, 4 m, 7 m, 10 m, 15 m, 20 m, 25 m, 35 m, and 50 m, with a maximum of 50 m and a maximum extension of once. The minimum bending radius for motor cables is approximately 150 mm dynamically, and for data cables it is approximately 60 mm. The cables should not withstand tensile forces and should be laid separately from the power lines. The connector must be locked during installation. When the motor connector is locked, there is a "click" sound and the red locking ring is not visible. If using an external axis, it is necessary to confirm the cascode RDC option and corresponding interface XP7.1/XP8.1.

Planned maintenance: Block faults before they occur

KR 25 R1840-3 maintenance node: Replace A5 gear oil by about 0.15 L and A4 by about 0.20 L after 20000 hours or 5 years. KR 35 R1840-3 maintenance node: Lubricate cable group A4 by about 0.06 kg and cable group A1 by about 0.08 kg after 10000 hours; replace A5 by about 0.15 L, A4 by about 0.20 L, A3 by about 0.40 L, A2 by about 1.10 L, and A1 by about 1.70 L after 20000 hours or 5 years. Before maintenance, the maintenance point must be accessible and any obstructing tools and accessories must be removed. If the oil temperature exceeds 60 ° C for a long time, the maintenance interval should be shortened and KUKA should be consulted. All accessories must use approved products, otherwise it may lead to early wear and tear.

Transportation, storage, and disposal

Transportation location: A1 0 °, A2-130 °, A3 168 °, A4 0 °, A5 0 °, A6 0 °. Use slings or forklifts, unauthorized lifting is prohibited. Improper installation of forklift slots may damage A1 and A2 cables, and installation instructions must be followed. The storage environment should be dry, dust-free, avoid temperature differences, and direct sunlight, with a temperature range of -25 ° C to 60 ° C. During disposal, the motor should not be disassembled, electronic components should be disposed of as electrical waste, plastics should be classified according to labeling, and gear oil and lubricating grease should be disposed of according to regulations.

Fault Handling Checklist

Emergency stop, power off, padlock, and power check first.

Check the alarm: motor, brake RDC、 Data cables and safety circuits.

Mechanical inspection: oil level, oil leakage, cables, hoses, base bolts.

Check parameters: load, center of gravity, inertia, installation angle, program magnification.

After replacement: Mastering, T1 testing, stop distance retest.

Record: Fault time, frequency, axle number, temperature, load, maintenance content.

The reliability of KUKA KR CYBERTECH-3 is based on standardized maintenance. By controlling the stopping distance, gear oil, cable lubrication, zero point calibration, base bolts, and connecting cables, most on-site faults can be detected in advance. For engineers, the true idea of "replacing discontinued modules" is not to wait until they break before replacing them, but to use verifiable parameters and standard steps to turn every maintenance into a traceable quality record.