What is the true payload capacity of the NexBot TBL021-004, and how is it affected by the end-effector?
Explains how to calculate the usable payload for the NXB-ROB-TBL021-004 robot arm by accounting for the weight and center of gravity of the end-of-arm tooling (EOAT).
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This article clarifies the 10 kg payload specification for the NexBot Robotics TBL021-004 Collaborative Robot Arm and details how to calculate the effective or 'net' payload based on your selected End-of-Arm Tooling (EOAT).
Answer
The NexBot Robotics TBL021-004 Collaborative Robot Arm is rated for a maximum total payload of 10 kg. This figure, often called the 'gross payload', represents the total mass the robot can manipulate at its tool flange (the mounting point on Axis 6, or J6) without exceeding its operational limits for motor torque, component stress, and motion accuracy.
Crucially, this 10 kg capacity must include the weight of any installed End-of-Arm Tooling (EOAT), such as a gripper, sensor, welding torch, or dispenser. The actual weight of the part or material you can handle, known as the 'net payload', is what remains after subtracting the weight of your tooling.
Formula: Net Payload = Gross Payload (10 kg) - EOAT Weight
For example, if your gripper assembly weighs 1.5 kg, the maximum weight of the part you can handle with the NXB-ROB-TBL021-004 is 8.5 kg.
The Importance of Center of Gravity (CoG)
Beyond simple mass, the performance and longevity of the robot are significantly influenced by the EOAT's center of gravity (CoG). The robot's performance specifications, including its ±0.02 mm repeatability, are validated with a payload CoG located at a specific reference point, typically centered on the tool flange.
An EOAT that is large, long, or has an off-center mass will create higher moment forces on the robot's joints, particularly J5 and J6. This can have several negative effects:
- Reduced Speed: The robot's controller will automatically limit acceleration and velocity to keep joint torques within safe limits, slowing down your cycle time.
- Increased Vibrations: A poorly balanced tool can introduce oscillations during high-speed moves, degrading the robot's ±0.02 mm repeatability and potentially affecting task quality (e.g., in dispensing or assembly applications).
- Premature Wear: Consistently operating with a high moment of inertia places additional stress on the robot's gearboxes and motors, which can lead to premature wear and a reduced operational lifespan.
Tips for Selecting and Configuring EOAT
To maximize the performance and usable payload of your NXB-ROB-TBL021-004, follow these best practices when selecting and configuring your tooling:
- Prioritize Lightweight Designs: Choose grippers and other tools made from lightweight materials like aluminum or composites whenever possible.
- Maintain a Compact Profile: Design or select an EOAT that keeps the combined CoG of the tool and the workpiece as close to the robot's tool flange as possible.
- Accurately Define Tool Properties: Within the NexBot Robotics control software, it is critical to accurately define the mass and the X, Y, and Z coordinates of your EOAT's center of gravity. This allows the robot's motion planner to calculate the dynamic forces correctly and optimize performance while ensuring safe operation. Failure to set these parameters can lead to inaccurate movements and potential safety faults.
Related Topics
- Mounting requirements for the NXB-ROB-TBL021-004.
- Configuring safety I/O and collaborative operating modes.
- Programming basic Pick & Place movements.