J. Tlusty

Bio: J. Tlusty is an academic researcher from McMaster University. The author has contributed to research in topics: Machining & Machine tool. The author has an hindex of 21, co-authored 22 publications receiving 3268 citations. Previous affiliations of J. Tlusty include University of Florida.

Use of Audio Signals for Chatter Detection and Control

Abstract: This paper compares various sensors and shows that a microphone is an excellent sensor to be used for chatter detection and control. Comparisons are made between the microphone and some other common sensors (dynamometers, displacement probes, and accelerometers) regarding sensing of unstable milling. It is shown that the signal from the microphone provides a competitive, and in many instances a superior, signal tht can be utilized to identify chatter. Using time domain milling simulations of low-radial-immersion, low-feed, finishing operations it is shown that for these cuts (especially at relatively high speeds) chatter is not adequately reflected in the force signal because of the short contact time, but that it is clearly seen in the displacement signal. Using the dynamics of existing production milling machines it is shown how the microphone is more suitable to chatter detection than other remotely placed displacement sensors, especially in cases that involve flexible tooling and workpieces. Aspects important for practical implementation of a microphone in an industrial setting are discussed. Limitations of the microphone are addressed, such as directional considerations, frequency response, and environmental sensitivity (i.e., workspace enclosure, room size, etc). To compensate for expected unwanted noises, commonly known directionalization techniques such as isolation, collection, and intensity methods are suggested to improve the ability of the microphone to identify chatter by reducing or eliminating background and extraneous noises. Using frequency domain processing and the deterministic frequency domain chatter theory, a microphone is shown to provide a proper and consistent signal for reliable chatter detection and control. Cutting test records for an operating, chatter recognition and control system, using a microphone, are presented; and numerous examples of chatter control are listed which include full and partial immersion, face-and end-milling cuts.

Manufacturing Automation: Metal Cutting Mechanics, Machine Tool Vibrations, and CNC Design

Abstract: Metal cutting is a widely used method of producing manufactured products. The technology of metal cutting has advanced considerably along with new materials, computers, and sensors. This new edition treats the scientific principles of metal cutting and their practical application to manufacturing problems. It begins with metal cutting mechanics, principles of vibration, and experimental modal analysis applied to solving shop floor problems. Notable is the in-depth coverage of chatter vibrations, a problem experienced daily by manufacturing engineers. The essential topics of programming, design, and automation of CNC (computer numerical control) machine tools, NC (numerical control) programming, and CAD/CAM technology are discussed. The text also covers the selection of drive actuators, feedback sensors, modeling and control of feed drives, the design of real time trajectory generation and interpolation algorithms, and CNC-oriented error analysis in detail. Each chapter includes examples drawn from industry, design projects, and homework problems. This book is ideal for advanced undergraduate and graduate students, as well as practicing engineers.

Chatter in machining processes: A review

Abstract: Chatter is a self-excited vibration that can occur during machining operations and become a common limitation to productivity and part quality. For this reason, it has been a topic of industrial and academic interest in the manufacturing sector for many years. A great deal of research has been carried out since the late 1950s to solve the chatter problem. Researchers have studied how to detect, identify, avoid, prevent, reduce, control, or suppress chatter. This paper reviews the state of research on the chatter problem and classifies the existing methods developed to ensure stable cutting into those that use the lobbing effect, out-of-process or in-process, and those that, passively or actively, modify the system behaviour.