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Inventions 2018, 3(1), 5;

Numerical Analysis of CNC Milling Chatter Using Embedded Miniature MEMS Microphone Array System

Master’s Program of Electro-Acoustics, Feng Chia University, Taichung 40724, Taiwan
Bachelor’s Program in Precision System Design, Feng Chia University, Taichung 40724, Taiwan
Author to whom correspondence should be addressed.
Received: 22 November 2017 / Revised: 11 January 2018 / Accepted: 12 January 2018 / Published: 16 January 2018
(This article belongs to the Special Issue Selected Papers from ICI2017 and Spintech Thesis Awards)
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With the increasingly common use of industrial automation for mass production, there are many computer numerical control (CNC) machine tools that require the collection of data from intelligent sensors in order to analyze their processing quality. In general, for high speed rotating machines, an accelerometer can be attached on the spindle to collect the data from the detected vibration of the CNC. However, due to their cost, accelerometers have not been widely adopted for use with typical CNC machine tools. This study sought to develop an embedded miniature MEMS microphone array system (Radius 5.25 cm, 8 channels) to discover the vibration source of the CNC from spatial phase array processing. The proposed method utilizes voice activity detection (VAD) to distinguish between the presence and absence of abnormal noise in the pre-stage, and utilizes the traditional direction of arrival method (DOA) via multiple signal classification (MUSIC) to isolate the spatial orientation of the noise source in post-processing. In the numerical simulation, the non-interfering noise source location is calibrated in the anechoic chamber, and is tested with real milling processing in the milling machine. As this results in a high background noise level, the vibration sound source is more accurate in the presented energy gradation graphs as compared to the traditional MUSIC method. View Full-Text
Keywords: beamforming; direction of arrival; voice activity detection; chatter detection beamforming; direction of arrival; voice activity detection; chatter detection

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Wang, P.-L.; Tsai, Y.-T. Numerical Analysis of CNC Milling Chatter Using Embedded Miniature MEMS Microphone Array System. Inventions 2018, 3, 5.

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