Design News, January 2013

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Fluid Power/Motion Control Source: HeidenHain closed Loop: Thanks to the precise linear and angle encoders from Heidenhain, errors in the drive mechanics have no influence on the result of machining. The seams are milled to the correct width, and the intersections all match up exactly. Aurora-Where_the_Action_Is:Aurora 11/5/10 1:10 PM Page 1 Rod Ends and Spherical Bearings designed and manufactured to Aurora's exacting standards for quality and durability. Registered and Certified to ISO-9001 and AS9100. From economy commercial to aerospace approved, we've got it all ! Aurora Bearing Company 901 Aucutt Road Montgomery IL. 60538 Complete library of CAD drawings and 3D models available at: w w w . a u r o r a b e a r i n g . c o m position control and are not compensated. Depending on the design of the drive mechanics, semi-closed loop control can result in positioning error in the turnabout movement of ±10 millidegrees and more. The accuracy of a rotary table can be dramatically improved by using precise angle encoders that measure worktable movements directly. The transmission error in the gears of rotary tables are ascertained by the angle encoder and therefore compensated in the position control (closed loop). In closed-loop operation, the precision of the angle encoder largely decides the accuracy of the turnabout movement. Angle encoders with optical scanning can make values of less than 0.3 millidegree possible. EncodErs Five-axis machining places particularly demanding requirements on the accuracy of feed drives because the traverse ranges and axis feed rate grow in comparison with 3-axis machining. The generation of heat and mechanical transmission error in the feed drives turn position measurement of the feed drives into a decisive factor for machining precision. Scrap and costs are minimized with the correct position acquisition. Therefore, linear encoders for linear axes as well as angle encoders for rotary and tilting axes are indispensable for machine tools on which high positioning accuracy and a high machining speed are essential. Dr. Jens Kummetz is head of application development at DR. JOHANNES HEIDENHAIN GmbH, in Traunreut, Germany. For more information, go to F10 f lu i d power/m o t i o n c o n t r o l / a s u p p l e m e n t t o d e s ign ne ws Ja n u a ry 2013 [ www.designnews .com ]

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