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Vision system identifies auto parts; Paper rolls centered with machine vision

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Vision system identifies auto parts

Perkins Engines Company (Peterborough, UK; www.perkins.com), a manufacturer of diesel engines, needed to track precise details on the characteristics of fuel injectors to maximize performance and reduce emissions. Laser-marked Data Matrix 2-D barcodes identify the performance characteristics of each injector, which must be installed in the proper engine during production. To track this, the company asked Absolute Vision (Meriden, UK; www.absolutevision.co.uk) to develop a solution for reading each barcode after it is installed into the cylinder head of the engine. The identification and location data are obtained by Absolute Vision’s Medusa Data Matrix reading system, which passes the data to Perkins’ database records for each engine.

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The Medusa system is a customized unit mounted on a counterbalanced swing arm. An operator inserts the injectors into the cylinder head and then swings the read head onto the engine and presses a single button to initiate the read cycle. Within the read head an array of imagers and lighting units acquire the code from each injector and transmit this identification to the database, where it is matched to the injector data provided with the injector shipment. The operator monitors the image-capture process, which takes only moments, via a simple array of LED indicator lights, and, once successfully completed, the read head is swung back into its parking position and assembly of the engine continues. Perkins has also installed six Absolute Vision Workstation DataMouse systems to replace conventional hand-held scanners for in-process verification.

Paper rolls centered with machine vision

Norske Skog (Lysaker, Norway; www.norskeskog.com), a producer of paper for newsprint and magazines, has 22 paper mills around the world. Its Tasman mill at Kawerau, New Zealand, produces more than 300,000 tons per year, enough for all the country’s newsprint and telephone directories, plus 25% of Australia’s newsprint needs. Paper is manufactured in wide rolls and then slit while rewinding onto cardboard tubes, called cores. These shorter rolls are sized specifically for printing presses. Keeping the rolls balanced as they are rewound onto the cores is a significant control challenge. Excessive eccentricity-the distance between the core center and the roll center-can cause vibration and web breaks on customer’s printing presses.

Norske Skog was using a manual measurement technique for detecting rolls with excessive off-center cores. This procedure was both time-consuming and subjective, with different operators achieving different results. The company turned to Control-Vision (Auckland, New Zealand; www.controlvision.co.nz) to provide an automated inspection solution. Limited space on the production line meant cameras and lighting needed to be mounted within 2 m of the roll surface. The imaging solution developed by ControlVision was based on 6-Mpixel cameras from PixeLINK (Ottawa, ON, Canada; www.pixelink.com) and Fujinon (Wayne, NJ, USA; www.fujinon.com) lenses. Safety concerns prevented the use of standard lighting, so large-diameter infrared ringlights from Spectrum Illumination (Montague, MI, USA; www.spectrumillumination.com), each comprising 48 LEDs, were used. Image calibration, pattern-matching, and edge-finding are performed in PC-based VisionPro software from Cognex (Natick, MA, USA; www.cognex.com). Combined with ControlVision’s VisionServer deployment environment, this vision system was developed and installed without the need to develop custom software.

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