Assessment of a three-axis on-rotor sensing performance for machining process monitoring: a case study

Abstract

Online monitoring of cutting conditions is essential in intelligent manufacturing, and vibrations are one of the most effective signals in monitoring machining conditions. Generally, traditional wired accelerometers should be installed on a motionless or stable platform, such as a tool holder or lathe bed, to sense vibrations. Such installation methods would cause the signals to suffer more serious noise interferences and a low signal-to-noise ratio, resulting in less sensitivity to valuable information. Therefore, this study developed a novel three-axis wireless on-rotor sensing (ORS) system for monitoring the turning process. The Micro Electromechanical System (MEMS) accelerometer sensor node can be mounted on a rotating workpiece or spindle rotor and is more sensitive in detecting the vibrations of the entire rotor system without any modification of the lathe system and interference in the cutting procedure. The processor, data acquisition, and Bluetooth Low Energy (BLE) 5.0+ modules were developed and debugged to cooperate with a piezoelectric triaxial accelerometer, with a vibration amplitude not larger than ± 16 g. A series of turning tests were conducted and the results were compared with those from the commercial wired accelerometers, which proved that the ORS system can measure the vibration signal of the rotor system more effectively and sensitively than wired accelerometers, thus demonstrating the accurate monitoring of machining parameters.

Characterizing the Vibration Responses of Flexible Workpieces during the Turning Process for Quality Control

“…To verify that the model established in this study provided a realistic description of a lathe processing a slender shaft, an experiment was conducted on a CZ6132A universal machine, shown in Figure 11a. To obtain a more sensitive vibration signal for the cutting parameters and entire rotor system, a novel three-axis wireless on-rotor sensing (ORS) system and a prototype for the turning system were developed, with a sampling rate of 3200 Hz [33]. The installation size of the three-axial acceleration sensor was designed according to the shaft diameter and lathe system.…”

Experimental Study on Entropy Features in Machining Vibrations of A Thin-walled Tubular Workpiece

“…The widely used sources of information on chatter are the process variables affected by the material removal progression. The most frequently measured signals are force [4], vibration [5][6][7], acoustics [8,9], current, or power [10,11]. Compared to other signals, cutting forces were regarded as more suitable for chatter detection, because this physical variable can directly characterize the dynamic interaction between the tool and the workpiece.…”

“…Lu et al [5] developed a comprehensive indicator for chatter monitoring when turning a long slender shaft, which integrates the time domain variance and spectral features of acceleration signals. Li et al [7] developed a novel three-axis wireless on-rotor acceleration sensing system for monitoring the turning process. Delio et al [8] adopted airborne acoustics to detect milling chatter and proved that a microphone could provide proper and consistent signals for reliable chatter detection and control in comparison with dynamometers, displacement sensors, and accelerometers.…”