System inspects circuit breakers

Automated system uses multiple images to check parts and provide traceability of numerous components.

Sep 17th, 2007

Automated system uses multiple images to check parts and provide traceability of numerous components.

The Osiswitch Compact line at Télémécanique, a Schneider Electric brand, makes circuit breakers, creating up to 2000 different product types from just 100 different components. Each circuit breaker is manually assembled, so a 100% reliable inspection of the individual components is essential to verify each breaker before packaging. Considering the variety of product types, it became clear that a mechanical system would not be sufficient to handle the inspection job. Vision technology was going to be the only solution.

System integrator Esox Technologies (Carquefou, France; www.esox.fr) and its partner Cognex (Natick, MA, USA: www.cognex.com) did a feasibility study and proposed an inspection solution that met the demands of the application. Explains Nicholas Charollais, marketing manager for Schneider Electric, "Our biggest risk regarding quality control is an unsatisfactory order; we need an inspection solution capable of verifying that each product packaged matches the right product reference. Fully automating the inspection line was essential."

The proposed vision system analyzes the product references. This analysis uses the vision platform developed by Esox with VisionPro from Cognex, which allows a "multidisplay" of images. The vision station is made up of two cameras and five LED light sources plus a laser beam. The first high-resolution camera (1600 × 1200 pixels) inspects the underneath of the piece and checks the code inscribed on the contacts; the second camera performs the inspection of the upper part of the piece. The acquired images are recorded in the inspection database.

Considering the extent to which the specifications can vary, putting in place a correct lighting system represented a serious challenge. Esox conceived an optical system with software programmed to operate according to exposure times. This system allows the lighting to be adapted to the product reference, so several lighting variations could be called upon in sequence depending on the product family.

Depending on the complexity of the ongoing product inspection, the system displays one or more images for each product component. Up to 12 images can appear in the form of frames, the system having acquired each of them by using the appropriate lighting. Each image is then processed by the software and the results of the inspection appear on each of these frames labeled as red or green, allowing the operator to visualize any problems rapidly.

Tests were completed in France. The first installation of the system was carried out on one of Schneider's Spanish production sites. After two weeks of testing, the production line was transferred to the Batam production site in Indonesia.

From their French sites, Schneider Electric can check images of faulty components in Indonesia, as well as control the inspection parameters or make modifications to programming. The system can archive all statistics, so it can monitor and confirm all nonconforming defects, identifying any false rejects if necessary. This kind of control also allows total traceability of inspected production.

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