The most significant characteristic in frequency domain during cutting chatter occurring process is the steep rise of the vibration energy in certain narrow frequency band containing the chatter frequency. In accordan...The most significant characteristic in frequency domain during cutting chatter occurring process is the steep rise of the vibration energy in certain narrow frequency band containing the chatter frequency. In accordance with the frequency band-energy principle, a reliable criterion for chatter judgement is proposed and the in-process detection of cutting chatter is realized by the use of microcomputer. This method has the advantages of rapidity, high sensitivity, accuracy and high resistance to interference. Some concrete measures taken in practical applications are also discussed.展开更多
Cutting chatter is a violent self-excited vibration between a tool and a workpiece.Its negative effects mainly include poor surface quality,inferior dimensional accuracy,disproportionate tool wear or tool breakage,and...Cutting chatter is a violent self-excited vibration between a tool and a workpiece.Its negative effects mainly include poor surface quality,inferior dimensional accuracy,disproportionate tool wear or tool breakage,and excessive noise.Therefore,early recognition and online suppression of chatter vibration are necessary.This paper proposes a novel synthetic criterion(SC)for early chatter recognition.The proposed SC integrates standard deviation(STD)and one-step autocorrelation function(OSAF).Moreover,this paper revised the fast algorithm of OSAF.We can quantitatively divide a chatter vibration signal into three stages,which are stable stage,transition stage and chatter stage according to the SC.Compared with STD,the SC can improve the reliability of chatter recognition and the threshold of SC is not sensitive to variable cutting conditions.This paper presents an original algorithm of SC and its fast algorithm in detail.The fast algorithm of SC in this paper improves the computation efficiency compared with the original algorithm of SC.To validate the effectiveness of the proposed SC,a series of milling experiments were conducted under different cutting conditions.In these experiments,the vibration signals were acquired by two accelerometers mounted on the spindle house.The experimental results showed that the proposed SC could effectively recognize chatter vibration at an early stage of chatter vibration,which saved valuable time for online chatter suppression.展开更多
A large aspect ratio vibration reducing tool holder based on passive damping vibration reduction technology is designed to solve the vibration problem that occurs in deep hole machining of vertical lathes.A dynamic mo...A large aspect ratio vibration reducing tool holder based on passive damping vibration reduction technology is designed to solve the vibration problem that occurs in deep hole machining of vertical lathes.A dynamic model of passive damping vibration reduction tool holder was established,and the optimal damping ratio,optimal frequency ratio,and maximum relative amplitude were derived.Modal analysis of the passive damping vibrationreduction tool holder was conducted using software.The results showed that the maximum response amplitude of the passive damping vibration reduction tool holder decreased significantly compared to the original one.展开更多
文摘The most significant characteristic in frequency domain during cutting chatter occurring process is the steep rise of the vibration energy in certain narrow frequency band containing the chatter frequency. In accordance with the frequency band-energy principle, a reliable criterion for chatter judgement is proposed and the in-process detection of cutting chatter is realized by the use of microcomputer. This method has the advantages of rapidity, high sensitivity, accuracy and high resistance to interference. Some concrete measures taken in practical applications are also discussed.
基金supported by the National Basic Research Program of China (Grant No. 2011CB706803)the National Natural Science Foundation of China (Grant Nos. 51175208, 51075161)Science Fund of Hebei University of Science and Technology (Grant No. XL201121)
文摘Cutting chatter is a violent self-excited vibration between a tool and a workpiece.Its negative effects mainly include poor surface quality,inferior dimensional accuracy,disproportionate tool wear or tool breakage,and excessive noise.Therefore,early recognition and online suppression of chatter vibration are necessary.This paper proposes a novel synthetic criterion(SC)for early chatter recognition.The proposed SC integrates standard deviation(STD)and one-step autocorrelation function(OSAF).Moreover,this paper revised the fast algorithm of OSAF.We can quantitatively divide a chatter vibration signal into three stages,which are stable stage,transition stage and chatter stage according to the SC.Compared with STD,the SC can improve the reliability of chatter recognition and the threshold of SC is not sensitive to variable cutting conditions.This paper presents an original algorithm of SC and its fast algorithm in detail.The fast algorithm of SC in this paper improves the computation efficiency compared with the original algorithm of SC.To validate the effectiveness of the proposed SC,a series of milling experiments were conducted under different cutting conditions.In these experiments,the vibration signals were acquired by two accelerometers mounted on the spindle house.The experimental results showed that the proposed SC could effectively recognize chatter vibration at an early stage of chatter vibration,which saved valuable time for online chatter suppression.
基金Science and Technology Research Project of Liaoning Provincial Department of Education:Research on the Application of Damping and Vibration Reduction Technology in Key Components of Machine Tools(JYTMS20230066)The Fund of Liaoning Provincial Natural Science and Technology Foundation Regional Joint(No.2021-YKLH-08).
文摘A large aspect ratio vibration reducing tool holder based on passive damping vibration reduction technology is designed to solve the vibration problem that occurs in deep hole machining of vertical lathes.A dynamic model of passive damping vibration reduction tool holder was established,and the optimal damping ratio,optimal frequency ratio,and maximum relative amplitude were derived.Modal analysis of the passive damping vibrationreduction tool holder was conducted using software.The results showed that the maximum response amplitude of the passive damping vibration reduction tool holder decreased significantly compared to the original one.
