Tool break/wear detection using a tracking minimum of detected vibrational signal
First Claim
1. A method of detecting machining tool wear comprising the steps of sensing vibration energy produced upon machining a workpiece with said tool;
- generating an electrical vibration signal corresponding to the sensed vibration energy;
processing the vibration signal to produce a tracking minimum signal which tracks the minimum values of the vibration signal;
comparing the tracking signal to a predetermined threshold level; and
indicating in response to the comparing, the tracking signal attaining a predetermined level relative to the predetermined threshold level.
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Abstract
Gradual wear or breakage of a machine tool which occurs over a period of time is detected by sensing high frequency vibrations produced at the cutting tool/workpiece interface during a machining process. The high frequency vibrations are converted to a unipolar vibration signal which is processed to produce a tracking signal which tracks the minimum value of the vibration signal. The vibration signal is related to the effective cutting energy and it decreases due to gradual tool wear or breakage. The tracking minimum signal is compared to a predetermined threshold level to detect excessive wear or breakage of the tool, and an alarm is provided.
18 Citations
19 Claims
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1. A method of detecting machining tool wear comprising the steps of sensing vibration energy produced upon machining a workpiece with said tool;
- generating an electrical vibration signal corresponding to the sensed vibration energy;
processing the vibration signal to produce a tracking minimum signal which tracks the minimum values of the vibration signal;
comparing the tracking signal to a predetermined threshold level; and
indicating in response to the comparing, the tracking signal attaining a predetermined level relative to the predetermined threshold level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
- generating an electrical vibration signal corresponding to the sensed vibration energy;
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12. A method of detecting gradual wear or breakage of a machine tool comprising the steps of measuring a parameter representative of total input power to the machine tool and producing a corresponding first signal;
- sensing vibrations produced during machining of a workpiece from a tool/workpiece interface and producing a corresponding second vibration signal;
processing the second vibration signal to produce a tracking minimum signal which tracks the minimum value of the vibration signal;
forming a ratio of the first signal to the tracking minimum signal; and
providing an output indication upon the ratio exceeding a predetermined threshold level.
- sensing vibrations produced during machining of a workpiece from a tool/workpiece interface and producing a corresponding second vibration signal;
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13. A system for monitoring a machine tool to detect wear comprising a vibration sensor for sensing vibrations produced during machining of a workpiece with said tool and for generating an electrical vibration signal corresponding to the vibrations;
- means for processing the vibration signal to produce a tracking minimum signal which tracks the minimum values of the vibration signal;
means for comparing the tracking signal to a predetermined threshold level; and
means for indicating, in response to the comparing means, the tracking signal attaining a predetermined level relative to the threshold level. - View Dependent Claims (14, 15, 16, 17, 18, 19)
- means for processing the vibration signal to produce a tracking minimum signal which tracks the minimum values of the vibration signal;
Specification