KUKA KR 3 AGILUS Operation and Maintenance Safety Essentials

KUKA KR 3 AGILUS Operation and Maintenance Safety Essentials

KUKA KR 3 AGILUS is a six axis industrial robot designed for miniaturization and high cycle scenes. The specific model KR 3 R540 is commonly used for tasks such as tool handling, workpiece processing, and product transportation. It has a compact structure, weighs approximately 26.5 kg, has a rated load of 2 kg, a maximum total load of 3 kg, a maximum range of motion of 541 mm, and a pose repeatability accuracy of ± 0.02 mm. It is suitable for various installation positions such as floors, roofs, and walls. For on-site engineers, what truly affects stable operation is often not a single parameter, but the coordination of installation, load, safety circuits, stopping stroke, connecting cables, and maintenance cycles. The following summarizes the key technical points of this model from the perspective of operation and troubleshooting.

Mechanical Structure and Axis Parameters

The KR 3 AGILUS robotic arm adopts a 6-axis light metal die-casting articulated arm motion system, with each axis equipped with a brake. The drive unit and live wires are arranged inside the cover plate to prevent dirt and moisture. The main components include the robot wrist, forearm, boom, turntable, base, and electrical equipment. The wrist is composed of A4, A5, and A6, and the forearm is connected to the upper arm through an A3 gearbox. The upper arm is located between the turntable and the forearm, and the turntable performs A1 rotational motion. The base is the base of the robot. The back of the base is equipped with an A1 interface, which connects the robot's mechanical system and control system.

In terms of axial motion range: A1 is ± 170 °, A2 is -170 °/50 °, A3 is -110 °/155 °, A4 is ± 175 °, A5 is ± 120 °, A6 is ± 350 °. At rated load, the speeds are approximately A1 530 °/s, A2 529 °/s, A3 538 °/s, A4 600 °/s, A5 600 °/s, A6 800 °/s. The zero calibration positions are A1 0 °, A2-90 °, A3 90 °, A4 80 °, A5 0 °, A6 0 °. If the robot is not operating on the ground, the tilt position angle must be accurately recorded in WorkVisual. The ground, walls, and ceiling are configured at different angles; Error in angle recording may lead to unexpected movement and/or overload of the robot.

Installation and foundation fixation

The foundation fixation usually uses a bottom plate with a fixing device, chemical anchor bolts, and positioning pins. The concrete foundation should meet the requirements of C20/25, with a flat and smooth surface, and no insulation or mortar layer is allowed between the bottom plate and the concrete. If the surface is uneven, it can be leveled with finishing mortar, but there should be no finishing mortar in the area below the hexagonal bolt. When installing, first determine the position of the bottom plate, check that the horizontal deviation is less than 3 °, then drill holes, install anchor bolts according to the manufacturer's instructions, and wait for the chemical anchoring agent to harden. When using chemical anchor bolts, anchor pipes and anchor bolts from the same manufacturer should be used, and diamond drill bits or bottom hole drill bits should not be used.

Rack fixation is suitable for steel structures, installation racks, or KUKA linear slides provided by customers. The installation surface must be clean, the hole diagram must be correct, use 4 hexagonal bolts M8x35 and disc washers, and use cylindrical positioning pins and flat positioning pins to center. The bottom structure needs to be able to reliably withstand foundation loads and maximum loads, with a bolt tightening force of approximately Fs=62 kN, and tensile strength materials such as S355J2G3. After the robot is installed, four M8x35 hexagonal bolts should be tightened again with a torque wrench after 100 hours of operation.

Connect the cable to the customer interface

The connecting cables include motor cables X20-XM1/XM2-6, data cables X21-X15/X18, and optional grounding wires. The robot side connection cable is firmly connected to the cable kit. When fixed laying, the bending radius of motor cables should not be less than 50 mm, and data cables should not be less than 30 mm; cables should be protected from mechanical impact, not subjected to tension, and only laid indoors, with a fixed laying temperature range of -10 ° C to+70 ° C. Motor cables and data cables should be laid separately, and additional electromagnetic compatibility measures should be taken if necessary. The grounding wire is used to establish a low resistance connection between the robot system and the control box, and the electrical connection is performed by the user.

The A1 customer interface is located on the back of the base, including the AIR1 to AIR4 air pipeline interface, with an outer diameter of 4 mm, a maximum pressure of 7 bar, and a vacuum negative atmospheric pressure of 0.95 bar; Interface MEMD X32; Drag chain system interface X76. The A4 customer interface is located under the A5 cover plate on the wrist, and the X96 interface must use a right angle plug and point towards the cable tray direction. The drag chain system X76-X96 has a rated current of 2 A, a rated voltage of 24 V, an M12 plug, 8 pins, and A standard coding. It is necessary to prevent overload and short circuit.

Load, inertia, and flange stress

KR 3 R540 has a rated load of 2 kg, a maximum load capacity of 3 kg, and a rated mass moment of inertia of 0.045 kgm ². The rated distance of the load center of gravity is Lxy 60 mm and Lz 80 mm. The total sum of all loads fixed on the robot shall not exceed the maximum total load. The load curve corresponds to extreme load capacity, and both load capacity and mass moment of inertia must be checked simultaneously. Exceeding the limit will affect the service life of the robot and overload the motor and gearbox. It is necessary to use KUKA. Load to check inertia and input load data into the robot control system.

In terms of flange force, the flange load during operation is approximately F (a) 194 N, F (r) 144 N, M (k) 21 Nm, M (g) 9 Nm; During emergency stop, it is approximately F (a) 244 N, F (r) 263 N, M (k) 35 Nm, and M (g) 19 Nm. These values are related to the load mass, center of gravity, moment of inertia, and motion trajectory. It is recommended to pay attention to fatigue strength when designing tools, and if necessary, measure the force and torque under the actual conditions of the robot's use site.

Safe operation and personnel requirements

This industrial robot is only allowed to be used according to regulations, that is, for handling tools and devices, or for processing and transporting workpieces or products. Unauthorized use includes using it as a climbing aid, using it outside the allowed operating range, and not using necessary additional protective devices. Changing the structure of the robot, such as punching holes, will be considered as improper use and may result in loss of warranty and claim eligibility. Robot systems are only allowed to operate on systems that comply with CE certification.

The system integrator is responsible for integrating industrial robots into equipment, conducting risk assessments, using necessary safety functions and protective devices, issuing EC conformity declarations, affixing CE marks, and creating equipment operation guidelines. Users must receive training and only personnel with professional qualifications are allowed to operate. The work area must be limited to the minimum range, and protective devices should be located within the protective area. Dangerous areas include work areas and stopping routes. Mechanical terminal stops, mechanical shaft limiting devices, free rotation devices, brake opening devices, and hazardous position markings are common protective equipment.

In terms of safety measures: It is not allowed to operate the robot with safety functions or protective devices deactivated or removed; Prohibit staying under the robotic mechanical system; During operation, the temperature of the motor may cause skin burns, and protective gloves should be worn. KCP/smartPAD is only allowed to be operated by authorized personnel, and multiple handheld programmers must be clearly matched with corresponding robots. When using an external keyboard and mouse, it must have been put into operation or maintained, the drive device must be turned off, and there must be no one in the danger zone. After being put into operation or maintenance, the external keyboard and mouse must be removed.

Stop travel and shutdown category

The stopping stroke refers to the angle of rotation of a robot from triggering a stop signal to complete stop, and the stopping time refers to the time taken from triggering the stop signal to complete stop. The data mainly focuses on the base axes A1, A2, and A3. Shutdown category 0 means the drive system will immediately shut down and the brake will apply; Shutdown category 1 is the mechanical arm braking along the trajectory, and after 1 second, the drive device is turned off and the brake is applied; Shutdown category 2 is when the drive system is not turned off, using regular brake ramp braking.

For shutdown 0, axis 1 has a stopping stroke of approximately 49.12 ° and a stopping time of 0.15 s; axis 2 has a stopping stroke of approximately 54.73 ° and 0.19 s; and axis 3 has a stopping stroke of approximately 86.99 ° and 0.24 s. These values are based on the operating range I=100%, program multiplier POV=100%, and mass m as the maximum load. The actual stopping stroke and stopping time may vary due to internal and external influences of braking torque. Depending on the operating mode, usage, and number of shutdowns, brake wear may vary. It is recommended to check the stopping stroke at least once a year. If the axis movements overlap with each other, the stopping stroke may become longer.

Transportation and commissioning

Before transportation, the robot must be placed in the transportation position: A1 0 °, A2-130 °, A3+150 °, A4 0 °, A5 0 °, A6 0 °. As long as the robot is not fixed on the foundation, it must be kept in the transportation position. When transporting with a circular sling, the sling must be threaded from below the boom towards the wrist of the robot, and all rope lengths and threading methods must ensure that the robot is not damaged. During transportation, avoid vibration or collision, and pay special attention to preventing tipping over. It is prohibited to use cranes to lift robots in other ways.

Before putting into operation, the equipment and devices should be checked for completeness and functional integrity. The inspection items include: correct placement and fixation of the robot; No external damage; No foreign objects or damaged, detached, or loose parts; The protective device is correctly installed and functioning properly; The equipment power is consistent with the power supply voltage and grid system; The grounding safety lead and potential balance wire have sufficient capacity and are correctly connected; Connect the cables correctly and lock the plugs. The password used to log in as an expert and manager must be changed before being put into operation.

Common troubleshooting ideas

One of the common problems on site is accidental movement or axis sinking of the robot. Possible reasons include incorrect installation angle recording, failure to input load data, brake failure, motor damage or overload. When troubleshooting, the installation location of WorkVisual, KUKA. Load load data, brake status, and mechanical damage should be checked. If the robotic arm or additional axis collides with obstacles, mechanical end stops, or axis limiting devices, the robot may no longer be able to operate reliably and must stop running and negotiate with KUKA.

The second issue is that the stopping stroke becomes longer or the machine stops abnormally. Should confirm the type of shutdown POV、 Scope of application, load mass, overlap of shaft movement, and inspection of brake wear. If the reason for the shutdown is unknown, it is only allowed to enter the danger zone after the emergency stop function has been activated. The third issue is a faulty connection cable or interface. Plug locking, bending radius, cable separation and laying, electromagnetic compatibility measures, grounding wire connection, and interface sealing should be checked. The fourth issue is that the foundation or frame is loose. Anchor bolts, locating pins, and hexagonal bolts should be checked for torque and re tightened after 100 hours.

Maintenance, repair, and tightening torque

After maintenance and repair, it is necessary to check whether it meets safety requirements and test all safety functions. Maintenance includes fault finding and repair. When doing homework, try to do it outside the danger zone as much as possible; If it is necessary to operate in a hazardous area, the operator must take additional protective measures. Shut down the industrial robot and take measures to prevent restart, such as padlocking. If it is necessary to work while the control system is connected, it is only allowed to operate in T1 mode, and a sign should be hung and emergency stop activation should be maintained. Before working on conductive components, the main switch must be turned off and the power must be verified. It is not enough to only trigger emergency stop, safety stop, or turn off the driving device.

After the robot control system is turned off, some components may still be charged, capacitors may discharge for several minutes, and the voltage may exceed 50V or even up to 600V. ESD regulations must be followed to prevent water and dust from entering the control cabinet. If the balance weight is a hydraulic pneumatic balancer or balance cylinder, it belongs to pressure equipment and must comply with pressure equipment instructions and domestic inspection deadlines. Dangerous goods should be avoided from prolonged skin contact, inhalation of oil mist and gas, and regular requests for safety data explanations.

In terms of tightening torque, unless otherwise specified, the 8.8 grade M8 is about 23.0 Nm, M10 is about 45.0 Nm, and M12 is about 78.0 Nm; the 10.9 grade M8 is about 31.0 Nm, M10 is about 60.0 Nm, and M12 is about 104.0 Nm; the 12.9 grade M8 is about 36.0 Nm, M10 is about 70.0 Nm, and M12 is about 125.0 Nm. The cap nut M5 is tightened at about 4.2 Nm. Bolts with a strength grade equal to or higher than 10.9 and bolts with test certificates can only be tightened once with the rated tightening torque, and must be replaced after being loosened again. Common auxiliary materials include adhesive and sealing materials, Harmonic Drive grease 4B No.2, Longtime PD 0, Microlube GL 261, Optitemp RB 2, etc.

Operation and maintenance suggestions

The stable operation of KR 3 AGILUS relies on standardized installation, correct load data, reliable and safe circuits, and regular maintenance. During the planning phase, it is necessary to avoid working conditions such as prolonged proximity to temperature limits, corrosive environments, power limits, long single axis connection times, monotonous repetitive movements, long-term vertical wrist movements, and external forces. Otherwise, premature wear may occur, and maintenance cycles or component replacements may need to be shortened. When a fault occurs, the control system should be turned off and locked first, with a tag indicating the fault and recording the phenomenon. Then, the safety function, drive, brake, connecting cable, load, and installation angle should be checked item by item. Only by considering mechanical, electrical, control, and safety as a whole can unplanned downtime be reduced and the KR 3 AGILUS maintain a stable rhythm in small handling, processing, and assembly scenarios.