Analysis and implementation of chatter frequency dependent constrained layer damping tool holder for stability improvement in turning process

Significance 

Machining vibrations, also called chatter, induced by the relative movements between the cutting tool and the workpiece is an inevitable phenomenon during metal cutting processes. It leads to irregular surface flaws that generally reduces the cutting accuracy, machining stability, and tool life. Whereas no mutual conclusion has been put forward as the main causes of chatter, weak stiffness property and low damping ratio are among the causes pointed out by different researchers, depending on the type of workpieces and tool holders. Therefore, to ensure high work quality as well as tool and workpiece safety, development of efficient cutter suppression techniques is highly desirable.

Among the available suppression strategies, active control, passive control, and cutting parameter tuning are the most used in overhang tool holders. For instance, cutting parameter tuning is based on the dynamic behavior of the machining systems induced by the effects of the process parameters, active chatter control depends on the use of smart actuators while the passive control strategies are mainly depended on improving the dynamic behaviors of the machining system using vibration absorbers. Alternatively, the use of composite damping structure has recently gained popularity in the research field. It enhances effective energy dissipation through the use of free layer damping and constrained layer damping materials. However, the latter is widely preferred for vibration elimination due to the additional shear deformation in the damping layer that increases the rate of vibration energy dissipation. Unfortunately, it has fixed dynamic behavior that affects its machining operations.

Recently, Shandong University researchers: Yang Liu (PhD candidate), Professor Zhanqiang Liu, Professor Qinghua Song and Dr. Bing Wang investigated the dynamic behavior of constrained layer damping tool holder structure taking into consideration the effects of the chatter frequency. In particular, they analyzed the effects of the dynamic behavior of the tool holder on the machining stability and especially during the turning operation process. They purposed to improve machining stability. The work is currently published in Journal of Materials Processing Technology.

Briefly, the authors commenced by investigating the mechanical properties of the viscoelastic materials to confirm that they indeed depend on the frequency and temperature. This was confirmed through testing of the frequency and modal parameters. Considering the viscoelastic properties, the effects of the chatter frequency on the dynamic behavior of the constrained layer damping tool holder was further investigated through analytical methods. To validate the machining stability and damping performance, they manufactured a constrained layer damping tool holder based on dimension simulation and performed various modal tests and cutting experiments.

The research team recorded an impressive damping ratio increase by 99% for the manufactured constrained layer damping tool holder. This was attributed to the decrease in the cutting forces and an increase in the cutter depth. For the turning operations, the chatter suppression ability varied at different spindle speed with respect to the variation in the chatter frequency. Additionally, a significant improvement in the machining stability with better damping performance was achieved. Therefore, the study provides vital information that will further improve the efforts to suppress machining vibration for efficient machining processes.

Analysis and implementation of chatter frequency dependent constrained layer damping tool holder for stability improvement in turning process - Advances in Engineering

About the author

Dr. Zhanqiang Liu is currently a professor and the head of Academic Committee of the School of Mechanical Engineering, Shandong University. He received his Ph.D. degree from the City University of Hong Kong in 1999. From 1999 to 2001, he was a Post-Doctoral Fellow with the School of Mechanical Engineering, Shandong University. From 2001 to 2002, he was an Associate Professor with the School of Mechanical Engineering, Shandong University, where he has been a Professor since 2002. His research interests include machining theory and tool technology. He is a member of American Society of Mechanical Engineers (ASME).

He was awarded as the National Science Fund for Distinguished Young Scholar of China in 2014, and also recognized as a Distinguished Professor in Shandong University. He recently made a pioneering contribution towards the high quality and high efficiency machining technology through development of a constrained damping cutting tool.

About the author

Mr. Yang Liu is currently a Ph.D. candidate at the School of Mechanical Engineering, Shanghai Jiao Tong University. He received his Master degree from Shandong University in 2017. His research interests include dynamics of cutting system and cutting tool.

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About the author

Dr. Qinghua Song is currently a professor at the School of Mechanical Engineering, Shandong University. He received his Ph.D. degree in mechanical engineering from Shandong University in 2009. From 2009 to 2011, he was a postdoctoral fellow at the school of materials science and engineering, Shandong University. From 2011 to now, he has been a lecturer, associate professor and professor at the school of mechanical engineering, Shandong University.

His research interests include cutting system dynamics; the structural vibration and control; micro process equipment technology.

About the author

Dr. Bing Wang is currently a postdoctoral research fellow at Georgia Tech Manufacturing Institute. He received his Ph.D. degree in mechanical engineering from Shandong University in 2016. He was a joint training Ph.D. student in the department of mechanical engineering at Michigan State University. From 2017 to 2018, he was a postdoctoral researcher at the school of materials science and engineering, Shandong University. His research interests include high speed machining, precision machining and material dynamic properties. He is a member of the American Society of Mechanical Engineers, Chinese Mechanical Engineering Society and Chinese Society of Aeronautics and Astronautics.

Reference

Liu, Y., Liu, Z., Song, Q., & Wang, B. (2019). Analysis and implementation of chatter frequency dependent constrained layer damping tool holder for stability improvement in turning processJournal of Materials Processing Technology266, 687-695.

Go To Journal of Materials Processing Technology

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