Scanning for Safety AUTOMATED INSPECTION SYSTEM EMPLOYS LINE SCAN CAMERAS TO ENSURE RELIABLE BRAKE DISC QUALITY. Flawless brake operation is so essential to the safety of a vehicle that all brake systems have passed safety testing before a driver ever gets behind the wheel. But how much better would you, as a driver, feel knowing that the raw brake discs of your motorcycle or minivan were Inspected for any flaws even before brake assembly began? And, from a manufacturing perspective, what if such an inspection yielded better quality while boosting profitability? A custom-designed machine vision inspection system from Ibea GmbH (Hamburg, Germany) uses cameras from Teledyne Dalsa (Waterloo, Ontario, Canada) to provide these benefits and more for automotive suppliers, manufacturers and customers alike. PUTTING THE BRAKES ON FAULTY PARTS Manufacturers tend to rely on manual inspections to detect nonconformities on raw brake discs. Frequent shift changes and the subjective nature of these inspections lead to lower reliability and, subsequently, to increased manufacturing costs resulting from returns. As a result, Ibea, which has developed, produced and integrated industrial processing systems since 1991, recently introduced an automated system that integrates the inspection and handling of brake discs. By replacing manual inspection methods and integrating production line components and machinery, the automated Ibea system provides automotive industry manufacturers with a comprehensive overview of the entire brake manufacturing process, and with a documented and reproducible method of ensuring brake disc quality. The Ibea inspection system is built around a simple centering device for well-defined rotation of brake discs with diameters up to 50 centimeters and heights up to 15 centimeters. As each disc rolls along a conveyor, it is transported into the test cell via a front-end entry pulsing device and, upon triggering a sensor, stops at the centering device. The disc is pre-centered by three rollers, one of which is driven, for exact centering. The disc then rotates 360 degrees, during which time three Teledyne Dalsa Spyder2 line scan cameras take images of the upper, lower and cooling channel sides of each disc. “I like to use Teledyne Dalsa cameras because of the vast selection of cameras, good quality and reasonable prices,” says Akram El Jarad, project manager at Ibea. Ibea had worked with Teledyne Dalsa previously to design customized systems for the metal sheet, abrasive paper, ceramic and other industries. On the brake disc inspection system, the images taken are arranged in such a way that all defects can be found using only one image acquisition and a dark field illumination technique. Since 90% of brake disc defects occur during the casting process— only about 10% are surface or core flaws—and involve indentations, dark field illumination can reliably detect any cavities. Contrast imperfections are handled separately. Discs are inspected at a rate of approximately six to 10 per minute for diameter and height, imprint or symbols, blowholes, flash, filled ventilation channels, half fans, bubbles in the fan, cracks and deformities. Good parts proceed along the conveyor while faulty ones are diverted and ejected from the line for rework. Using Ibea’s custom-designed program, disc parameters can be set, saved and started up by shop floor personnel. This handling and inspection procedure minimizes wear and tear on parts, makes expensive handling robots unnecessary and provides highly accurate images that also can be used for measurement purposes. Ibea introduced the brake disc inspection system to the market in 2009. This automated vision solution provides reproducible, seriesproduction quality that dramatically reduces the quantity of faulty parts shipped. According to El Jarad, the manufacturer’s investment can be recouped within 1.5 years. “The Teledyne Dalsa cameras that are the heart of this system provide a cost-effective, yet high-performance, solution,” he says.
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