Grinding Monitoring
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Grinding Monitoring Konrad Wegener* Institut f€ ur Werkzeugmaschinen und Fertigung (IWF), ETH Z€urich, Z€urich, Switzerland
Synonyms Condition monitoring
Definition Grinding monitoring comprises all technologies that enable to observe and analyze the grinding process, the energy conversion, the grinding tool, and the finished workpiece properties.
Theory and Application Introduction
The process “high-performance grinding,” from which high material removal rates, best surface quality and integrity, and high geometrical accuracy are required, is a highly sensitive process subject to numerous influences. Some of those influences today can hardly be predicted and also can hardly be directly controlled by input parameters to the grinding machine system. Especially the wear of the grinding tool, consisting of macro wear and micro wear, a truly complicated process, which is still today not fully understood, introduces unpredictable transient changes to the grinding wheel and thus into the process. Therefore, observation of the process becomes necessary. But observation alone is insofar not sufficient as only by help of suitable process and measuring theory the necessary informations for the evaluation and subsequently control or even closed-loop control of the process can be distilled out. The accessible data stem from the different sources: direct access to the wheel surface by optical means reveals directly the deterioration of the tool. Energy conversion, forces, power, heat generation, and acoustic emission comprise different aspects of the process behavior, and finally, measuring the workpiece discloses the grinding results to decide. All three groups can be used to take corrective measures only after interpretation. Also contact detection by acoustic emission, though it is not used for continuous monitoring of the process, is subgrouped to grinding monitoring, and it is one of the most frequently applied methods in industry. Wear is the prevailing process responsible for transient behavior of the grinding process. Besides the contact detection, all monitoring is at the same time an indirect or direct wear monitoring. Macro wear deteriorates the workpiece geometry, whereas micro wear is responsible for the change of the process and is made up from attritious wear, pullout, grain break, wear of the bond, and loading of the grinding wheel as reviewed in Wegener et al. (2011). There also can be found further literature on monitoring. Depending on the control data also chatter might be detected that can also be affected by wear.
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CIRP Encyclopedia of Production Engineering DOI 10.1007/978-3-642-35950-7_6423-4 # CIRP 2015
Monitoring of Macro Wear Detecting macro wear requires measurement of the diameter, the profile, and the geometric runout. Runout yields signals varying with the rotation angle and thus can be detected by measuring the force or power signal such that it also portrays a unique footprint within the AE signals. The diameter is directly derived from the positiona
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