Research On Tool Condition Monitoring And On-line Compensation Technology In Milling Special Spiral Rod

Tool condition monitoring is the key technology in automatic processes, which plays an important role in milling special spiral rod by reducing manufacturing cost & environment pollution, ensuring production quality, and improving automation degree. In this dissertation, the mathematical model of tool wear and breakage is first setup, and then the tool condition monitoring system is developed to achieve on-line tool dimension compensation and tool breakage prediction.The main research contents of the dissertation are summarized as follows:(1) Tool condition analysis and signal detectionFirst tool wear and breakage mechanism in rod milling is analyzed and all typical fettle signals are contrasted. Then the vibration signal and power signal which can fully reflect the tool state are adopted as the research object. Finally signals are detected through sensor installment, sampling program establishment and A/D transform.(2) Feature extraction of vibration signals based on wavelet transform.During the process of milling special spiral rod, vibration signals in a certain frequency strip can fully reflect the current tool state. So group filtering via wavelet transform is constructed first. And tool wear & breakage character signals are extracted based on which vibration amplitude change and tool state is mapped. Thereby eigenvalue of tool condition is calculated, and tool wear & breakage condition is identified qualitatively.(3) Feature extraction of Power signals based on statistics technique.Original power signal can only reflect the change of milling parameter, but not the tool wear information. Hence the statistics technique is adopted to dispose the original power signal by root-mean-square, which is then regressed to the smooth curve and regarded as the tool wear character signal. The character signal can sufficiently reflect tool wear and cutting parameter change, therefore the qualitative identification of tool wear condition is realized.(4) Tool wear and breakage model building based on the sensor fusion.