UR3e vs Rainbow Robotics RB3-730: 3 kg Cobot Comparison of Price and Reach
The Universal Robots UR3e and the Rainbow Robotics RB3-730 are 3 kg cobots of the same weight on the same Ø128 mm base. The RB3-730 reaches 230 mm further and costs about 31% less. The UR3e repeats more tightly and has built-in force sensing.
Quick verdict. The Rainbow Robotics RB3-730 is the value choice for small-part assembly, inspection and education, with 730 mm reach and a listed price about 31% lower. The UR3e is the better choice for precise and force-controlled benchtop work, with ±0.03 mm repeatability and a ±30 N / ±10 Nm force/torque sensor.
UR3e and RB3-730 at a glance
The UR3e carries 3 kg over 500 mm, repeats to ±0.03 mm and weighs 11.2 kg.
The Rainbow Robotics RB3-730 carries 3 kg over 730 mm, repeats to ±0.05 mm and weighs 11 kg.
Main specification comparison
Specification | Universal Robots UR3e | Rainbow Robotics RB3-730 |
Brand | Universal Robots | Rainbow Robotics |
Listed price | $33,800 | $23,400 |
Payload | 3 kg | 3 kg |
Reach | 500 mm | 730 mm |
Repeatability | ±0.03 mm | ±0.05 mm |
Axes | 6 | 6 |
Speed | 3 m/s maximum TCP speed | Joint speeds: J1 to J4 180°/s, J5 and J6 360°/s |
Arm weight | 11.2 kg | 11 kg |
IP rating | IP54 | Not specified |
Controller | UR control box CB 5.5 / CB 5.6 | Rainbow Robotics CB07 small robot control box |
Price comparison
UR3e: listed from $33,800
Rainbow Robotics RB3-730: listed from $23,400
Difference: $10,400
The RB3-730 costs roughly 31% less
Reach and footprint
Both arms carry 3 kg, weigh about 11 kg and sit on a Ø128 mm base. The RB3-730 reaches 730 mm, 230 mm more than the UR3e, which covers a wider bench from one position. It mounts in any orientation.
Precision and speed
The UR3e publishes ±0.03 mm repeatability and a 3 m/s maximum tool speed. Rainbow Robotics publishes ±0.05 mm and joint speeds up to 360°/s on the wrist for the RB3-730. Precise electronics assembly and insertion favor the UR3e.
Sensing, control and certification
The UR3e has a built-in ±30 N / ±10 Nm force/torque sensor and runs PolyScope with PROFINET, EtherNet/IP, Modbus TCP, ROS/ROS2 and UR+ accessories. The RB3-730 runs on the compact CB07 control box and is CE, KC and TÜV SÜD certified per ISO/TS 15066.
Best applications for the UR3e
Precise benchtop assembly
Force-controlled insertion
Robots inside machines
Best applications for the RB3-730
Small-part assembly and dispensing
Inspection over a wider bench
Education and research
UR3e advantages
±0.03 mm repeatability
Built-in force/torque sensor
UR+ ecosystem
UR3e limitations
About $10,400 higher listed price
500 mm reach
RB3-730 advantages
About 31% lower listed price
730 mm reach
Compact CB07 control box
RB3-730 limitations
±0.05 mm repeatability
Final verdict
Choose the Rainbow Robotics RB3-730 for reach and value. Choose the UR3e for precision and force control.
Sources and further reading
Frequently asked questions
Which is cheaper, the UR3e or the Rainbow Robotics RB3-730?
The RB3-730 is listed from $23,400 and the UR3e from $33,800, a difference of $10,400.
Do both robots carry 3 kg?
Yes. Both are rated for 3 kg.
Which robot has the longer reach?
The RB3-730 reaches 730 mm and the UR3e 500 mm.
Which robot is more precise?
The UR3e publishes ±0.03 mm repeatability and the RB3-730 ±0.05 mm.
Do they weigh the same?
Almost. The UR3e weighs 11.2 kg and the RB3-730 11 kg.
Which robot should I buy?
Choose the RB3-730 for reach and value. Choose the UR3e for precision and force control.
