Risk assessment for a collaborative robot packing cell

Thornbury moulds medical device housings. At the end of one press, an operator picks each part from a chute, inspects it under a lamp and packs it into a box. The plant wants a collaborative robot (cobot) to pick parts from the chute and place them on an inspection tray, then pack the approved parts into boxes. The inspector stays at the same bench, about 900 mm from the robot base, and reaches into the shared area to reject parts.

The cobot is a six-axis arm with 1,300 mm reach and a 10 kg payload. With its vacuum gripper and a part, the tool load is 3.2 kg. At full speed the tool would move at 1.0 m/s, and the planned cycle is 9 s a part.

The production manager assumed that because the robot is "collaborative" it needs no guarding. The health and safety lead disagrees. Before the cell is built, they want a risk assessment that would stand up to scrutiny in the UK and in Ontario, following the general approach of ISO 12100 for risk assessment, ISO 10218 for industrial robot safety, and the collaborative-operation guidance from ISO/TS 15066.

You will: - describe the application and the limits of the machine; - identify hazards across the whole life of the cell, not only normal running; - estimate risk and choose reduction measures in the right order; - calculate the protective separation distance for speed and separation monitoring with a safety laser scanner; - check transient contact energy for the places where contact with the inspector could still happen; - simulate the layout and zones in CoppeliaSim or Webots to check the robot slows and stops as planned; - write a validation plan and a summary for the technical file.

You need no robot. The work is calculation, simulation and structured writing.

Done looks like a hazard log, a separation distance and contact check you can defend, a simulated layout with scanner zones, and a summary the health and safety lead can sign. This project teaches the method. It does not replace a competent person signing off a real cell.