Safety Notice: Risk of Unexpected Motion During Manual Guidance on TBL021-002 Cobot

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• 3-Position Enabling Device

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This document provides critical safety information regarding the NexBot Drives TBL021-002 Collaborative Robot Arm 10kg Payload. All personnel responsible for the installation, operation, programming, and maintenance of this equipment must read and understand this notice to prevent serious injury.

There is a potential hazard of unexpected robot motion when the robot is being operated in a manual guidance or 'teach' mode. This can occur if safety configurations are improperly set or bypassed, leading to a risk of impact or crushing injuries to personnel in the collaborative workspace.

Hazard Description

The NXB-ROB-TBL021-002, part of the C-10 series, is designed for safe collaboration with human operators. However, during specific tasks such as programming, manual part handling, or maintenance, operators may need to physically guide the robot arm. If the collaborative safety features—such as Power and Force Limiting (PFL)—are not correctly configured for the specific task, payload, and tool, the robot may move unexpectedly. Such motion could exceed safe collaborative speeds or forces, creating a significant hazard.

This risk is most acute when an operator is in close proximity to the robot, physically holding the arm or end-effector. An unexpected lurch, drop, or rapid movement could occur without warning, providing the operator with insufficient time to react.

Affected Product

• SKU: NXB-ROB-TBL021-002
• Product Name: NexBot Drives TBL021-002 Collaborative Robot Arm 10kg Payload
• Series: C-10 Series

Conditions Leading to Hazard

Unexpected motion can be triggered by one or more of the following conditions:

• Incorrect Payload and Tool Configuration: The control system relies on precise data for the payload mass, center of gravity, and tool dimensions to calculate safe motion dynamics. Failure to enter accurate values can cause the arm to behave erratically, especially when compensating for gravity or during acceleration/deceleration.
• Improper Use of Freedrive/Manual Guidance Mode: Activating manual guidance without ensuring that the robot is in a reduced speed, safety-rated mode can lead to high-speed movements if the operator inadvertently triggers a programmed motion.
• Bypassed or Misconfigured Safety Settings: Disabling or setting incorrect limits for safety functions like joint speed, tool speed, or power/force monitoring creates a dangerous operating environment. These settings must be configured by a qualified person based on a formal risk assessment.
• External Forces: Pushing or pulling on the robot arm with excessive force can cause the safety system to register a fault and trigger an emergency stop, which may itself be abrupt. Conversely, a sudden release of applied force can cause a recoil motion.

Mandatory Safety Procedures

To mitigate the risk of injury, all personnel must adhere to the following procedures when interacting with the NXB-ROB-TBL021-002 robot arm in a collaborative workspace.

1. Conduct a Thorough Risk Assessment

Before deploying the robot, a comprehensive risk assessment compliant with local and international standards (e.g., ISO 10218, ISO/TS 15066) must be performed for the specific application. This assessment must identify all potential hazards and define the necessary safety measures, including the correct configuration of all collaborative safety functions.

2. Ensure Proper Operator Training

Only personnel who have received certified training on the NexBot C-10 series robots and are familiar with the specific application's safety concept are authorized to program or manually operate the NXB-ROB-TBL021-002.

3. Always Use an Enabling Device

During any manual guidance, programming, or maintenance task that requires an operator to be inside the safeguarded space while power is enabled, a three-position enabling device (also known as a 'dead man's switch') must be used. This ensures that robot motion is immediately halted if the operator releases the switch or grips it too tightly in a panic situation.

4. Verify Payload and Tool Center of Gravity (TCP) Settings

Before initiating any motion, manual or programmed, verify that the active payload and tool settings in the control software accurately reflect the installed end-effector and workpiece.

• Step 1: Navigate to the 'Payload & Tool' configuration screen in the NexBot control pendant.
• Step 2: Enter the precise mass (in kg) of the end-effector and any part it is holding.
• Step 3: Accurately define the X, Y, and Z coordinates for the center of gravity of the payload.
• Step 4: Save and apply the configuration. The robot will use this data for its dynamic model.

5. Operate in Reduced Speed Mode

When teaching points or manually guiding the arm, always ensure the robot is in a safety-rated reduced speed mode. The maximum allowable speed for such operations should be determined by your risk assessment, typically not to exceed 250 mm/s.

6. Test Safety Functions Regularly

Periodically test the functionality of all configured safety features, including power and force limiting stops, emergency stops, and enabling device functions, according to the schedule outlined in the product's maintenance manual.

Failure to comply with these procedures may result in serious injury or death. If you are uncertain about any aspect of the robot's safe operation, do not proceed. Power down the system and consult your supervisor or contact NexBot Robotics support.

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