Acoustic monitoring of cutting conditions to detect tool break events
Patent 4636780 Issued on January 13, 1987. Estimated Expiration Date: 
October 24, 2004. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
October 24, 2004. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3793627 3842663 Apparatus for detecting damages of cutting tools Acoustic detection of tool wear and fracture Method and arrangement for determining tool wear Rotating tool wear monitoring apparatus Worn tool detector utilizing normalized vibration signals Patent #: 4514797 InventorsApplicationNo. 06/664188 filed on 10/24/1984US Classes:340/680, Machine tool340/683, Vibration700/175, Condition of tool or workpiece (e.g., tolerance, tool wear)73/104, SURFACE AND CUTTING EDGE TESTING73/660Rotating machinery or deviceExaminersPrimary: Rowland, James L.Assistant: Hofsass, Jeffery Attorney, Agent or FirmInternational ClassesG05B 19/4065 (20060101)G05B 19/406 (20060101) AbstractThis tool break detection system relies on monitoring changes in the cutting noise itself, rather than detecting the tool fracture acoustic signal. A broken tool capable of damaging the workpiece is detected, and tool break events that do not affect cutting conditions are ignored. The signal from a sensor such as an accelerometer is preprocessed to attenuate low frequency machinery noise and detect the signal energy in a band below 100 KHz, then sampled, and the digitized signal samples analyzed by pattern recognition logic. Runout false alarms during rough surface cutting are prevented; after detection of an abrupt increase or decrease in signal level, the confirmation period to test for a persistent shift in mean level is set longer than the workpiece revolution period. | |
