Robots and vision pack lettuces

El Dulze, a family run business that produces lettuce, uses 68 robots in a packaging system installed by system integrator IT Robotics.

El Dulze (El Mirador, Spain), a family run business that produces lettuce, uses 68 robots in a packaging system installed by system integrator IT Robotics (Alicante, Spain). Picked lettuce heads are delivered to the plant in plastic containers stacked onto a pallet where a Fanuc Robotics (Coventry, UK) R2000iB removes one tray at a time and pours the tray contents onto the packaging line conveyor. The input conveyor orientates the lettuce heads so that they travel longitudinally onto the system conveyors.

Positioned centrally on the input conveyor and spaced individually, the lettuce is directed to Fanuc LR Mate 200iB robot cutting stations. The lettuce is orientated lengthwise on the conveyor but the root end is randomly positioned. Based on weight, a vision system measures the diameter to assess the density of the lettuce. Lettuce falling outside acceptable parameters is rejected. The vision system also identifies the root position to the robot, which then picks up the lettuce with a pneumatic gripper.

The robot positions the lettuce in a cutting machine where the root is removed. A second check is made on the size of the lettuce as the robot holds the lettuce under a camera. Lettuce heads that passes this final inspection is conveyed to an operator working at the robot station and placed into a plastic tray. Full trays are placed back onto the conveyor and sent to the packing area. The plant is capable of packaging 550,000 heads of lettuce and is currently operating at 400,000 per day.

Posted by Conard Holton, Vision Systems Design

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