Chatter detection using vibrational and acoustic emissions in turning process

2013-09-20
Süleyman, Büyükkoçak
Kılıç, Şener
Özer, Mehmet Bülent
Ünver, Hakkı Özgür
Chatter vibration is a longstanding problem for machining industry. It lowers both surface finish quality and life of cutting tool. In this study, real time chatter vibration detection system is designed and tested experimentally. A traditional lathe, equipped with two accelerometers placed on cutting tool in two orthogonal coordinates and a microphone, is used for machining a steel rod in face turning operation. During cutting process analog data of accelerometers and microphone is acquired by data acquisition card that is connected to a computer. A Matlab graphical user interface that has the capability of acquiring and processing accelerometer and microphone data simultaneously is generated. Processing data is done by means of calculating coherences between accelerometer vs. accelerometer data and accelerometer vs. microphone data and comparison of coherences to threshold values that are tuned experimentally. Coherence function determines if two data signal come from the same source or not. Coherence functions value of data pair reaches unity at the chatter frequency. Three chatter conditions are described as stable, slight and severe chatter conditions. If both coherences exceed threshold values, severe chatter occurs. If one of the coherences exceeds and other doesn't than slight chatter occurs. If both of the coherences don't exceed threshold values then the system is stable. Depending on the chatter condition Matlab graphical user interface alerts the operator by indicator that changes color for different conditions. Graphical user interface also shows Fast Fourier Transform of the microphone data. Real time detection allows operator to change lathe speed or cutting depth in case of chatter occurs during the cutting process. By preventing chatter vibration, surface quality of the work-piece and life time of the machine tool is increased.
20th Annual International Conference on Mechatronics and Machine Vision in Practice, M2VIP 2013, (20 September 2013 through 20 September 2013)

Suggestions

Vibration reduction of structures by using nonlinear tuned vibration absorbers
Doğan, Muhammed Emin; Ciğeroğlu, Ender; Department of Mechanical Engineering (2019)
Tuned Vibration Absorbers (TVA) are commonly used in reducing undesirable vibrations of mechanical structures. However, TVAs work in a very limited frequency range and if the excitation frequency is outside of this range, they become ineffective. In order to solve this problem, researchers started to consider nonlinear TVAs for vibration attenuation. In this study, dynamic behavior of a Linear systems coupled with a nonlinear TVA is investigated. The system is subjected to sinusoidal base excitation. Parame...
Vibration isolation of inertial measurement unit
Çınarel, Dilara; Ciğeroğlu, Ender; Department of Mechanical Engineering (2012)
Sensitive devices are affected by extreme vibration excitations during operation so require isolation from high levels of vibration excitations. When these excitation characteristics of the devices are well known, the vibration isolation can be achieved accurately. However, it is possible to have expected profile information of the excitations with respect to frequency. Therefore, it is practical and useful to implement this information in the design process for vibration isolation. In this thesis, passive ...
Analytical modeling of the machine tool spindle dynamics under operational conditions
Özşahin, Orkun; Özgüven, Hasan Nevzat (null; 2012-07-27)
Chatter is an important problem in machining operations, and can be avoided by utilizing stability diagrams which are generated using frequency response functions (FRF) at the tool tip. In general, tool point FRF is obtained experimentally or analytically for the idle state of the machine. However, during high speed cutting operations, gyroscopic effects and changes of contact stiffness and damping at the interfaces as well as the changes in the bearing properties may lead to variations in the tool point FR...
Chatter reduction in boring process by using piezoelectric shunt damping with experimental verification
Yıgıt, Ufuk; Ciğeroğlu, Ender; Budak, Erhan (2017-09-15)
Chatter is a self-excited type of vibration that develops during machining due to process structure dynamic interactions resulting in modulated chip thickness. Chatter is an important problem as it results in poor surface quality, reduced productivity and tool life. The stability of a cutting process is strongly influenced by the frequency response function (FRF) at the cutting point.
Analytical modeling of spindle-tool dynamics on machine tools using Timoshenko beam model and receptance coupling for the prediction of tool point FRF
Erturk, A.; Özgüven, Hasan Nevzat; Budak, E. (2006-12-01)
Regenerative chatter is a well-known machining problem that results in unstable cutting process, poor surface quality and reduced material removal rate. This undesired self-excited vibration problem is one of the main obstacles in utilizing the total capacity of a machine tool in production. In order to obtain a chatter-free process on a machining center, stability diagrams can be used. Numerically or analytically, constructing the stability lobe diagram for a certain spindle-holder-tool combination implies...
Citation Formats
B. Süleyman, Ş. Kılıç, M. B. Özer, and H. Ö. Ünver, “Chatter detection using vibrational and acoustic emissions in turning process,” presented at the 20th Annual International Conference on Mechatronics and Machine Vision in Practice, M2VIP 2013, (20 September 2013 through 20 September 2013), Ankara, Turkey, 2013, Accessed: 00, 2021. [Online]. Available: https://hdl.handle.net/11511/78285.