Analysis of Milling Dynamics Under Cutting Fluid Supply by Using The Sound Sensor

• Main Authors: Pao-Ting Liu, 劉保廷
• Other Authors: Rong-Mao Lee
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/7556u8

碩士 === 國立勤益科技大學 === 機械工程系 === 105 === Detection and verification of milling chatter is possible with various sensors which can measure force, displacement, velocity, acceleration, acoustic signals generated from a machining process. Identification of milling vibration based on cutting noise can be accomplished by two kinds of sensors: non-contact and contact meacurement. Microphones are the non-contact sensor and mainly utilized to record the audible sound signal for human ears (20-20kHz). On the other hand, the acoustic emission (AE) sensor can be employed to monitor the vibration signals inside the solid structure. There are advantages and disadvantages for both of these two kinds of sensors. Since the microphone installation can be regulated easily according to the experiment requirements, this audible sound sensor is employed in this work. Limitations for microphones to monitor milling vibration have been reported in the past two decades such as the accuracy of vibration identification under the influence of environmental and aero-acoustic noise. In addition, almost all of the current researches for cutting noise analyses are conducted without cutting fluid (dry cutting). This is far from the practical milling situation. In this work, both of the microphone and the cutting fluid have been involved in the intensive cutting tests. For the purpose to ensure the operation of the microphone, a waterproof device has been specially designed. The signal of acoustic that are dry and wet milling is discussed by the Scatter Diagram of Time Domain (SDTD), and the transformaition in the maximum peak frequencys are observed by Fast Fourier Transform (FFT) and Short Time Fourier Transform (STFT). Finally, the milling surface is compared with the Stability Lobes Diagram (SLD).