KUKA KR 20 SCARA CS Robot Selection and Maintenance Guide

KUKA KR 20 SCARA CS Robot Selection and Maintenance Guide

Product family: 20kg heavy-duty SCARA platform

KUKA KR 20 SCARA CS is a family of four axis articulated arm (SCARA) robots designed for heavy-duty picking, placing, assembly, and handling applications. The controller uses KR CS Box-2, the teaching pendant is smartPAD touch, and the system software is KUKA. ControlStudio. The family includes four models: KR 20 R800 Z450 CS, KR 20 R1000 Z450 CS, KR 20 R1200 Z450 CS, and the cleanroom version KR 20 R1200 Z390 CS CR. Compared with the KR 13 SCARA-2 CS family, this series has increased the maximum load from 13 kg to 20 kg, catering to heavy-duty handling and large component assembly scenarios.

The robotic arm is a 4-axis articulated arm kinematic system, mainly composed of: arm body (Arm, connecting ball screw spline and connecting rod arm, built-in A3/A4 axis motor, driven by A2 motor, swing angle is mechanically limited by overtravel protection devices in both forward and reverse directions), ball screw spline, connecting rod arm (Link arm, located between arm body and base, swing angle is also mechanically limited), base frame (built-in electrical device and motor/data cable, energy supply system interface) and electrical devices (protection circuit, A1-A4 motor and data cable, I/O cable, trachea, Ethernet cable, controller connection cable).

Prohibited items are consistent with the KUKA general framework: not to be used as climbing aids, not to operate outdoors, not to be used in explosive areas/radioactive environments/underground mines, not to transport personnel and animals, and not to operate without safety equipment. Deviation from the technical data specifications can lead to premature wear and tear. Such applications require consultation with KUKA services, and robots can only operate in systems that meet CE requirements.

Horizontal comparison of core parameters of four models

Parameter item R800 Z450 R1000 Z450 R1200 Z450 R1200 Z390 CR

Workspace volume 0.731 m ³ 1.202 m ³ 1.652 m ³ 1.432 m ³

Repetitive accuracy XY ± 0.025 mm ± 0.025 mm ± 0.035 mm ± 0.035 mm

Self weight approximately 59.7 kg, approximately 61.3 kg, approximately 63.2 kg, approximately 64 kg

Rated/maximum load 10/20 kg 10/20 kg 10/20 kg 10/20 kg 10/20 kg

A1 speed 350 °/s 270 °/s 245 °/s 243 °/s

A2 speed 475 °/s 450 °/s 390 °/s 390 °/s

A3/A4 speed 0.91 m/s/1400 °/s same left, same left, same left

Cycle time 0.46 s 0.48 s 0.50 s 0.52 s

Protection level IP20 IP20 IP20 IP54

Noise<75 dB (A)<75 dB (A)<75 dB (A)<80 dB (A)

Cleanliness (ISO 14644-1) - Level 5 (100% override)

Common parameters: A1/A2 stroke ± 140 °, A3 stroke -450 mm to 0 (CR version -390 mm), A4 stroke ± 360 °; The zero calibration positions of all four axes are 0; Installation location on the ground, occupying only 230 × 235 mm; controller KR CS Box-2; Default color KUKA Industrial Orange (RAL 2009)+Signal White (RAL 9003); Environment level 3K22, operating at 0-45 ° C, storage and transportation at -25 ° C to 55 ° C. Before operating at low temperatures, it is necessary to reduce speed and acceleration and preheat before normal use.

Three selection rules are worth noting: firstly, the vertical speed of A3 is 0.91 m/s, and the rotation speed of A4 is 1400 °/s, which remain constant throughout the entire family. The increase in arm span only sacrifices the rotation speed of A1/A2; Secondly, the repeatability accuracy of both the R1200 standard version and the CR version is ± 0.035 mm, and the long arm model sacrifices accuracy for coverage range; The third is the CR version, which sacrifices IP54 and Class 5 cleanliness by shrinking the Z-stroke from 450 mm to 390 mm and reducing the maximum inertia of the flange from 1 kgm ² to 0.5 kgm ².

The A3 axis allows a process force of 250 N as standard across the entire range - pressing, testing, and other processes can be directly undertaken by A3.

Load and flange design

Rated at 10 kg, maximum at 20 kg. Designed for a rated load of 10 kg to optimize dynamic performance; Under the premise of reducing the distance between the center of gravity of the load, it is allowed to use a maximum load of 20 kg, which needs to be confirmed with KUKA support. The maximum value of additional load on the arm is 0 kg, but the support frame under the arm can bear supplementary load - visual cameras and other equipment are mounted on the support frame under the arm without the flange end, which is different from the KR 13 series' "2 kg under the arm" regulation. The additional load column in this data sheet is 0, and the specific load-bearing capacity of the support frame needs to be confirmed with KUKA according to the diagram. The load inertia must be verified using KUKA. Load and input into the controller, with the center of gravity offset minimized as much as possible to suppress vibration.

The flange is self-made by the user (not included in the supply scope), and the flange load is given according to the rated load without a safety factor. During operation, the load continues to appear in the normal trajectory, and the tool is checked for fatigue strength; Emergency stop values rarely occur, static strength verification is sufficient. Insufficient tool design can lead to fracture and failure, and it is necessary to calculate and use the prescribed installation equipment on a case by case basis according to the load.

Foundation load - structural input for ground installation

Load item R800 R1000 R1200 R1200 CR

F (v) Normal/Maximum 1113/1066 N 1127/1081 N 1151/1104 N 1238/1024 N

F (h) Normal/Maximum 1452/1610 N 1203/1268 N 1102/104 N 1056/1195 N

M (k) Normal/Maximum 849/864 Nm 816/783 Nm 840/909 Nm 823/897 Nm

M ®  Normal/Maximum 345/749 Nm 373/706 Nm 357/738 Nm 370/756 Nm

The load and self weight inertia force are already included, and the foundation is checked according to the maximum value. The pattern of this series is that the "maximum value" of the torque term is significantly higher than the "normal value" (such as the M value of R800) ® The maximum torque of 749 Nm compared to normal 345 Nm indicates that the peak torque of SCARA high-speed rotation around A1 under a specific trajectory is much higher than the typical average - the frame anti torsion design must be executed according to the maximum value and cannot be applied across models: the R800 has a maximum horizontal force of 1610 N, which is the highest in the entire family, and the R1200 CR has a normal vertical force of 1238 N, which is the highest in the entire family.

Stop distance - direct input for safety fence design

According to Appendix B of DIN EN ISO 10218-1 (Extension l=100%, Project Velocity=100%), under STOP 0 rated/maximum load:

Model A1 A2 A3

R800 Z450 110.85°/0.68 s · 102.28°/0.70 s 124.92°/0.54 s · 115.87°/0.64 s 79.06/88.63 mm

R1000 Z450 100.75°/0.75 s · 90.56°/0.83 s 101.53°/0.48 s · 86.96°/0.96 s 75.89/78 mm

R1200 Z450 109.96°/0.87 s · 120.34°/1.01 s 70.9°/0.50 s · 57.57°/0.49 s 79.82/84.90 mm

R1200 Z390 CR 126.08°/0.98 s · 138.29°/1.33 s 61.09°/0.42 s · 53.04°/0.48 s 59.61/55.16 mm

There are three key findings: firstly, the CR version A1 axis STOP 0 has a maximum load stopping distance of 138.29 ° and a time of 1.33 seconds, which is the longest in the entire family - the cleanroom version protective fence design must not use standard version data; Secondly, the "rated vs maximum load" data directions of A1 and A2 are inconsistent (some have longer maximum load stopping distances, while others have shorter ones). Due to the coupling relationship between braking torque and inertia, fence design must take the maximum value for each operating condition; Thirdly, the STOP 1 data is about half of STOP 0 (such as R800 A1 rated at 62.86 ° to 110.85 °), and applications with safety gate circuits prioritize configuring Stop 1 to significantly compress the safety distance. Stacking axis motion will lengthen the stopping distance; Brake wear is related to the number of Stop 0 triggers, and it is recommended to check the stop distance at least once a year.

Security protection boundary: The controller directly supports the safety door sensor, while other devices such as light curtains and presence sensors are not directly supported. If they need to be used, a risk assessment and certification scheme must be completed by oneself.

Installation foundation and interface system

Installation foundation (to be provided by the user): 4 M12 or M14 bolts are tightened, and the base must be made of steel, with a thickness of not less than 20 mm and a flatness of not more than 0.4 mm. The maximum horizontal deviation of the base is 5 °, and 2 positioning pins are used for positioning. The robotic arm is slowly lowered vertically (tilting will damage the positioning pins) and tightened diagonally in steps. The iron law remains unchanged: screws with a strength grade of 10.9 or above, grade 70/80 stainless steel, and certified by testing are only allowed to be tightened once with the rated torque, and must be replaced after the first loosening.

Interface system: A1 interface (back of base) includes user connector X40 (I/O), X74 (8-pin M12 X-code Ethernet), three-way air source AIR 1/2/3 (Ø 6/Ø 8 air tube, maximum 0.7 MPa, vacuum to -0.095 MPa), X30 motor cable, X31 data cable and grounding connection. The A2 interface (on the central arm) includes a brake release button, X94 Ethernet extension, X41 I/O extension, air circuit adapter, and motor operation indicator light. A wiring space of at least 200mm must be reserved behind the A1 interface. User cable discipline: It is strictly prohibited to tie cables to corrugated pipes, highly flexible shielded cables must be used, and the stress state and working space must be confirmed after installation without restrictions; The central arm reserves a user cable support interface, and the base can borrow some bolt holes.

Cable system: motor cable X30 and data cable X31, standard version uses WEIPU WS series, CR version uses WEIPU WF series; Length standard 5 m, optional 10 m; fixed laying bending radius motor cable not less than 55 mm, data cable not less than 45 mm; operating temperature -30 ° C to+80 ° C; motor and data cable laid in metal slots and strengthened EMC; The grounding conductor must be equipped with M4 ring terminal according to DIN EN 60204 and connected to the base frame by the user.

Manual movement and transportation

Manual dual path movement: A1/A2 axis activates Servo Free mode through ControlStudio and enables corresponding axis in the software, slowly moving by hand push; A3/A4 axis press and hold the arm brake release button to release. Key warning: When the button is pressed, the load may fall and must be held by hand.

Transportation position: A1=-90 °, A2=-90 °, A3=-100 mm, A4=0 °. Forklift transportation is used for the original packaging state; Lifting and transportation (optional) must use Qingling DF fixed plate (0000-433-013) and fixed plate B (0000-433-014): 5 M6x20-12.9 (9.5 Nm) are used to fasten the two fixed plates, and 3 M10x17 lifting rings (9.5 Nm) are installed. The rope length must be greater than 1500 mm and follow the path shown in the diagram. No other lifting methods are allowed. The center of gravity positions of the R800/R1000/R1200 three arm arms are different (such as the R1200 center of gravity distance of 922.1 mm), and the transportation dimension table must be checked according to the model before lifting.

Maintenance cycle table - the complete timeline of this series

Cycle task consumables

Tighten 4 M12/M14 mounting bolts for 100 hours (only once) -

100 km or 1500 h lubricated ball screw spline THK AFB-LF approximately 10 g

4000 hours or 1 year replacement of corrugated pipe (KUKA authorized personnel) 2525 corrugated pipe 0000-446-917

4000 hours or 1 year replacement of toothed belt A3/A4 (KUKA authorized personnel) A3: 0000-434-702, A4: 0000-434-704

4000 hours or 1 year cable group coated with Optitemp RB2 grease, approximately 20 g

1-Year Battery Replacement Standard 0000-339-818/CR 0000-439-232

Tighten installation bolts for 1 year -

Replace Optigear ALR 320 with A1 reducer oil after 20000 hours or 5 years, initial installation 0.37 L

Key points for screw lubrication: Press and hold the brake release button on arm A2 to move A3 to the upper limit position (do not hit the limit block) → Release button → Activate emergency stop → Remove old grease → Brush THK AFB-LF → Move to the lower limit position again and repeat. The CR version requires dismantling the top 8 M4x8-8.8 screws to move the bellows down, lubricating them, and then reinstalling them (2.8 Nm). Clean up excess grease and empty A3/A4 to evenly distribute the grease.

Tension calibration of toothed belt: After replacement, use a frequency meter TSM alpha 2 (0071-053-386) in conjunction with a tensioning fixture to measure. Move the belt and sensor 2-3 mm away from the vibration belt. Readings: A3 belt (150MTS3M927) target 59-70 Hz, A4 belt (150MTS5M1000) target 83-90 Hz. Adjust the M5x25-12.9 adjustment screw to meet the standard. If the fluctuation value after adjustment deviates within 30% of the table, it is considered normal. Before calibration, it is necessary to "break in": adjust A4 axis ± 20 ° back and forth 2-3 times, adjust A3 axis upper and lower limits back and forth 2-3 times, and then retest - skipping break in and locking directly will cause tension drift after operation. During assembly, the A4 belt is inserted into the lead screw from above and moved down with the transition pulley assembly. The belt must mesh correctly with the pulley. M6x25-12.9 is tightened diagonally in steps to 15 Nm after A3 moves vertically 3 times. Note that when loosening the A3 motor or A3 belt, the load may cause A3 to suddenly fall down, so A3 must be fixed first.

Key points for battery replacement: 10 M4x12-8.8 battery boxes on the front of the base, remove the cover → screw 2 M5 screws into the threaded holes of the battery box and pull out the battery box → insert the new battery into the empty connector first and then remove the old battery occupying connector → cut the zip tie to remove the old battery → reinstall the new battery, only use zip ties to tie the battery body, do not tie the battery cable → reinstall (2.8 Nm). At the end, it is necessary to check whether the zero point is lost, and if necessary, recalibrate A1/A2/A3/A4.

Key points for A1 oil change: The gear unit must be at operating temperature and A1 level. Remove 10 M4x12-8.8 cable box covers → replace the oil drain pipe with the lower M10x1 magnetic plug → ventilate and drain the upper 2 M10x1 magnetic plugs → measure the amount of oil discharged and recharge according to this amount - if the amount discharged is less than 70%, rinse the gearbox with the discharged oil once and recharge it; Less than 50% (if installed at an angle) needs to be flushed twice, during which the full stroke motion axis of the jog speed is required. Clean the magnetic plug and inspect the sealing components. Tighten to 7.5 Nm and perform a leak test.

Cleaning boundary: prohibit high-pressure cleaning equipment, prohibit compressed air blowing bearings and sealing points; Only solvent-free, water-soluble, non flammable, and non corrosive cleaning agents are allowed; Cleaning agents are strictly prohibited from entering electrical and mechanical system components; After cleaning the corroded area, apply anti-corrosion agent again.

Zero point calibration - Differences between standard version and CR version

After replacing components such as motors, reducers, cables, batteries, etc., the zero point may shift and must be recalibrated:

A1/A2: Prioritize using the calibration fixture (Calibration_1A/A20000-396-617), insert it into the calibration slot for alignment, and select Set Current on the ControlStudio calibration page; When there is no fixture, two calibration slots can be visually aligned, but there may be errors in relying on manual judgment.

A3/A4 (labeled A4 first and A3 later): Dev. KR20 CS A3A4 mastering (0000-435-989) is used for the standard version, and dedicated tooling (0000-438-020) is used for the CR version. Process: Tighten the calibration pin to the lower cover of the central arm → Install the calibration kit at the lower end of the screw → Rotate and align the threaded hole and insert the positioning screw → Move A3 to make the groove on the L-shaped bracket seamlessly contact the calibration pin → Rotate A4 to make the notch of the calibration bracket fit the calibration pin → Set Current to set A4 zero point. Alternative method without tooling: The standard version sets the A4 zero point by aligning the calibration mark of the lower limit block of the lead screw with the mark on the lower cover of the central arm (when there is no mark, mark the line by aligning the center of the rectangle at the lower end of the lead screw with the groove on the lower cover); Subsequently, A3 is moved to the upper limit position → A4 returns to zero → A3 is moved down 19 mm and set as A3 zero point - this 19 mm offset is the core data without tooling calibration and must be executed accurately. The conclusion is to conduct a trial run in T1 mode and observe any abnormalities.

Early wear warning and retirement disposal

During the planning phase, five types of accelerated wear conditions must be evaluated: temperature limit or corrosive environment continuous operation, performance limit continuous operation, single axis high load rate, monotonic motion trajectory, external process force - any of which must be consulted with KUKA. The built-in monitoring automatically shuts down when reaching or approaching the operating limit. Quantitative red line: The temperature of each axis motor should not exceed 368 K (+95 ° C). Long term overheating directly shortens the lifespan of the robotic arm. It is recommended to include it in the equipment health dashboard through ControlStudio trend monitoring.

Retirement process: Adjust to transport position → Remove all peripherals and motor/data cables → Release grounding conductor → Remove 4 M12/M14 bolts and washers → Carefully lift off the installation surface. Attention: When the robotic arm is stuck on the installation surface, it may suddenly detach, and the fasteners and adhesives must be completely removed. Eight requirements for long-term storage: dry and dustproof, avoid temperature fluctuations, prevent wind from passing through and condensing, use environmentally resistant coverings, leave no loose parts, avoid direct sunlight, and comply with storage temperature; Wrap with plastic film and seal at the base, and add desiccant under the film if necessary. Scrap classification: The base/arm/connecting rod arm is made of cast aluminum, the reducer/screw spline/fastener is made of steel, the electronic components are treated as electronic waste and cannot be disassembled, and the motor is disposed of as a whole; Lubricant Accessories Archive: Harmonic Drive 4B No.2 and Sumiplex SFB No.1 (gearbox), THK AFB-LF (lead screw), Microlube GL 261 (motor), Optitemp RB2 (cable), Drei Bond 1342/1305/5204HV and Sikaflex-221, LOCTITE 510 (adhesive seal).