scholarly journals On passive damping in machine tool hybrid structural parts

Author(s):  
Viktor Kulíšek ◽  
Petr Kolar ◽  
Pavel Vrba ◽  
Jan Smolík ◽  
Miroslav Janota ◽  
...  
Author(s):  
Jan Smoli´k ◽  
Viktor Kuli´sˇek ◽  
Miroslav Janota

New, higher and challenging properties of new high-speed machines and high-performance machines bring up many questions connected to the design and properties of the main machine tool structures. Parameters like static stiffness, eigenfrequencies, modal damping and mass of parts may be identified as very important, and all these properties need to be improved. The most important material properties in the field of machine tools are presented in this paper. A case study based on a modification of a real horizontal machining centre is introduced. The modification consists in using a sandwich design concept in the main structural machine tool part. The sandwich concept, widely known and used in the aerospace industry and, more generally, the transportation industry, is not commonly used in machine tool design. A significant reduction of mass has been achieved by manufacturing a hybrid column with aluminum foam cores, while static stiffness has not been affected.


Author(s):  
Yang Tian ◽  
Zhifeng Liu ◽  
Xiangmin Dong

Because of the characteristics of heavy-duty machine tools such as large self-weight and heavy load, the working precision and service life of their lathe beds, columns, and other large structural parts are all directly influenced by the foundation. In view of the considerable influence of joint surfaces on system characteristics, this study involved obtaining joint surface parameter values from a microscopic perspective, deriving a static joint surface parameter model from Reynolds equation, adopting fractal theory to develop a bolted joint surface parameter model, and thus completing the embedding of joint surface parameters under uneven loads; a simulation model for a heavy-duty machine tool-foundation system was also devised considering the influence of joint surfaces. To identify the structural micro-deformation status of heavy-duty numerical control machine tool-foundation systems, the authors constructed a fiber grating technology-based experimental platform for detecting the deformation of structural parts, verified the correctness of the above simulation model via experiments, and proposed a method for detecting the deformation of heavy-duty machine tool-foundation systems using fiber grating technology. Based on the above simulation model, the influence of reinforced layer position, foundation outline specifications and soil properties around the foundation on the bearing deformation of heavy-duty machine tool-foundation systems were studied, and some guidelines on the construction of concrete foundations were formulated. This model and the related detection method laid a theoretical foundation for guiding the design and optimization of heavy-duty machine tool structure and foundation.


2018 ◽  
Vol 12 (5) ◽  
pp. 621-621
Author(s):  
Michael F. Zaeh

Automation of machine tools has made them more productive, thereby providing an advantage for sustainability and the welfare of mankind. However, in many cases, the successful automation of machine tools requires the avoidance of self-excited chatter vibrations, resulting in a reliable stable state for cutting. Machine tool operators tend to use the machines close to their power thresholds, thereby unknowingly driving them toward the limits of their stability. Much progress has been made in the last few decades concerning the understanding and prediction of such vibrations, and this has led to improvements such as higher cutting rates and chip thicknesses. Several countermeasures such as active and passive damping are available for avoiding chatter vibrations in machine tools. However, their industrial use is not common yet. In fact, the industry is somewhat unfamiliar with many of these countermeasures. The hesitant attitude of the machine tool builders to apply such countermeasures is a result of several factors: active and passive damping devices are additional system components that require design, tuning, and maintenance. Furthermore, they are associated with a risk of failure, resulting in additional down times of the machines. Additionally, if a machine requires such devices to achieve the desired specifications, the customer’s opinion regarding it can be negatively affected. This situation is challenging for machine tool builders, users, and academia as well. Therefore, we decided to dedicate a special issue of IJAT to this topic. This special issue focuses on both active and passive damping measures, particularly the measures that are systematically designed and deliberately implemented to increase the chatter-free depth of cut in machine tools. The papers in this issue identify successful applications or at least a vision for them. Additionally, models demonstrating the effects of the chosen active or passive damping systems are presented. Some of these models can also be used to systematically select the parameters of the system. Some of the systems can be easily applied as low-cost patch-up solutions to improve the behaviors of the machines already in use. I hope that this special issue delivers a valuable overview of the existing approaches to introduce additional damping in machine tools. I would like to sincerely thank all the authors for their dedication and the well written and illustrated manuscripts. I would also like to thank the reviewers for their efforts to ensure the quality of this issue. Finally, I am very thankful to IJAT for their immense cooperation and support. I wish you all the best and hope that you can benefit from the content of this special issue.


1969 ◽  
Vol 48 (4) ◽  
pp. 169
Author(s):  
K. Foster ◽  
G.A. Parker
Keyword(s):  

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