KUKA KR 700 PA maintenance troubleshooting

Practical Maintenance and Troubleshooting of KUKA KR 700 PA Stacking Robot

KUKA KR 700 PA is a 4-axis industrial robot designed for heavy-duty palletizing, handling, and workpiece transportation scenarios. It has a rated load of 700 kg, a maximum total load of 750 kg, a working range of 3320 mm, a repeatability of ± 0.08 mm, a total weight of approximately 2850 kg, a protection level of IP65, and a noise level of less than 72 dB (A). For engineers in the "search for solutions" stage, the real factors that affect equipment availability are often not basic parameters, but installation, maintenance, oil change, motor replacement, balance weight inspection, and electrical connection failures. This article focuses on KR 700 PA and KR 700 PA arc, and outlines a practical maintenance and troubleshooting approach.

Check the core parameters first to avoid exceeding the limit of operation

The KR 700 PA adopts a 4-axis parallelogram motion system, with main axes A1, A2, A3, and A6. The axis motion range is limited by software: A1 is ± 185 °, A2 is+10 ° to -120 °, A3 is+150 ° to -10 °, and A6 is ± 350 °. In terms of speed, A1 and A2 are about 76 °/s, A3 is about 67 °/s, and A6 can reach 168 °/s. The workspace volume is about 73 m ³, and the reference point is the intersection point between A6 and the connecting flange plane.

The load capacity must be checked against two values simultaneously: load mass and mass moment of inertia. The rated load on the wrist is 700 kg, the distance between the center of gravity of the load Lz is 300 mm, Lxy is 350 mm, and the allowable moment of inertia is 350 kgm ². The small arm allows an additional load of 50 kg, while the large arm and turntable have an additional load of 0 kg. The connecting flange is similar to DIN/ISO 9409-1-A200, using M12 bolts with 23 fastening threaded holes, with a minimum depth of 15 mm and a maximum depth of 19.5 mm, and a through-hole of ø 60 mm. If the center of gravity, moment of inertia, or additional load of the tool exceeds the load diagram, it will cause motor and gearbox overload, and must be negotiated with KUKA.

Environmental conditions are equally critical. The standard operating temperature is from 0 ℃ to+55 ℃, with Safe RDW operating from 0 ℃ to+50 ℃, and storage and transportation from -40 ℃ to+60 ℃. KR 700 PA arc operates at temperatures ranging from -30 ℃ to+10 ℃ and is suitable for low-temperature environments. Humidity requirements shall comply with DIN EN 60721-3-3, 3K3 level. If operating under conditions such as temperature limits, corrosive environments, high speeds, frequent short stroke movements, or long-term vertical rest of the wrist axis, the maintenance cycle should be shortened.

Safe shutdown and hazardous area control

The hazardous areas of KR 700 PA include the working area, the stopping stroke of the robotic arm, and the stopping stroke of the additional shaft. The stopping stroke is equal to the reaction stroke plus the braking stroke. This model defines STOP0, STOP1, and STOP2: STOP0 is used to immediately turn off the drive and brake, while the robotic arm guides the brake along the path; STOP1 is braking along the trajectory, T1 mode robot stops or shuts off the drive at the latest 680 ms, T2/AUT mode shuts off after 1.5 seconds; STOP2 means that the drive does not turn off, the brake does not brake, and the slope brake is applied according to the trajectory.

In manual operation, T1 is for slow testing ≤ 250 mm/s, and T2 is for fast testing>250 mm/s. After debugging a new program or changing a program, it must be tested under T1 first. If it is necessary to debug within the protective isolation area, the operator should choose a location where the hazardous area can be observed. The personnel should maintain a reference distance of at least 50 cm from the robotic arm and tools, and the actual distance should be determined by risk assessment.

The power-off operation must be carried out by turning off the main switch and preventing restart. Even if the controller is turned off, some components may still be charged up to 780 V and last for several minutes. Before starting the homework, it is necessary to confirm the power outage, notify relevant personnel, and hang signs. The controller with a transformer needs to turn off the transformer first. Follow ESD regulations when operating components. Active implant personnel must maintain a distance of at least 300 mm from the motor, applicable in both powered and powered off states. High temperature motors pose a risk of burns, and protective gloves must be worn. KCP or smartPAD must be clearly assigned to the corresponding robot, and disconnected smartPAD/KCP should be immediately removed from the system.

Installation, transportation, and re-entry into operation

Ground installation can use 175mm or 200mm foundation fixing devices, or rack fixing devices. The recommended concrete strength is C20/25. The foundation surface should be smooth and flat, and there should be no insulation or mortar layer between the foundation slab and the concrete. If the bottom plate is not completely flat, it can be filled with filling mortar, but there should be no filling mortar under the fixing bolts. The horizontal deviation should be less than 3 °. Robot installation typically uses 8 M24x70-8.8 hex bolts and disc washers, which are tightened diagonally in stages to 640 Nm. After 100 hours of operation, they must be tightened again.