Kinetic Systems, Inc.

Paul S Mahr

John W Tippie

Michael L Hayes

A system for the detection of broken and worn machine tools which may be employed to protect machine tools using one or more machine tool bits and an automatic sequence of machining instructions comprising one or more machining steps. Piezoelectric load cells translate the force applied between the machine tool bit and the workpiece into electrical signals, one of which is selected, sampled, and processed into a series of force values by an analog module, one average force value for every revolution of a machine tool spindle. For the first pass on a first workpiece by a particular machining operation, force value maxima are learned for each machining step, and broken and worn tool force limits are calculated from these force maxima for each machining step. During this learn pass, each recorded force value is compared against predetermined learn ceiling in order to protect the machine tool. During successive passes on subsequent workpieces wear limits are calculated based on the force maxima of the learn pass and break limits are calculated based on the force maxima of the preceding pass. Whenever a learn ceiling, wear limit or break limit is exceeded, the system commands the machine to cease its cutting operation. To increase accuracy, the force values are sampled several times during one spindle revolution and are averaged. A graphing utility may optionally be employed to plot average force value versus revolution number.

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Lockport, IL, United States of America

Paul S Mahr