A wireless instrumented milling cutter system with embedded PVDF sensors

Abstract

Among all the monitoring data which could be captured in a machining process, the cutting forces could convey key knowledge on the conditions of the process. When the machining involves a single cutting edge the relationship between the output forces (measured with off-the-shelf dynamometers) and condition of the process, is somehow straight forward. However, when multiple cutting edges are in contact with the workpiece, the conventional dynamometers, that cannot separate the reaction forces on each cutting edge, loose significant information that could be used to in-detail monitor the machining process. To this end, this paper presents a novel concept of instrumented wireless milling cutter system with embedded thin film sensors in each cutting inserts, thus the cutting forces acting on each cutting edge could be monitored without reducing the stiffness and dynamic characteristics of the machining system. For this to happen, a dedicated milling force decoupling model for the developed instrumented milling cutter system is proposed and calibrated, and for the first time the accurate online estimation of the separate inserts' working conditions is achieved. The validation demonstrates a satisfactory agreement between the forces measured from the dynamometer and the proposed monitoring system prototype with the error less than 10%. Furthermore, the experimental results also indicate that the monitoring system prototype could also identify the tool insert conditions such as worn and chipped, which could be of high relevance to the analysis of the insert failure mechanism and its progress. Not only the proposed method and easy implementable but above all, it allows the monitoring of the condition (e.g. worn, chipped) of each insert, ability that has not been previously reported.

Cutting Forces Measurement for Milling Process by Using Working Tables with Integrated PVDF Thin-Film Sensors

“…Ma et al [ 21 ] used PVDF sensors to pick up the dynamic shear strain produced in the rotating tool during the cutting process. Luo et al [ 22 ] integrated the PVDF thin-film sensors into the index-able tools to measure cutting forces acting on separate insert, the signals are transmitted by a wireless transmitter, and the signals are then used to identify the insert working condition in the milling process. Liu et al [ 23 ] designed an integrated rotating dynamometer based on fiber Bragg grating (FBG) to measure four-component cutting force.…”

Upgraded Kalman Filtering of Cutting Forces in Milling

“…The moderate frequency bandwidth of modern dynamometers could be extended in three ways: by improving the device hardware, i.e., by selecting sensors and electromechanical components having higher performances; by improving the mechanical design of the device, e.g., by reducing the modal mass in front of the force sensors as described in [ 12 , 13 , 14 , 15 ]; and by applying advanced filtering techniques to the measured signals, which may considerably extend the frequency bandwidth above the structural limits [ 16 ]. …”

“…by improving the mechanical design of the device, e.g., by reducing the modal mass in front of the force sensors as described in [ 12 , 13 , 14 , 15 ]; and…”

Wear evolution and stress distribution of single CBN superabrasive grain in high-speed grinding

“…Cubic boron nitride (CBN) as super abrasive, has excellent chemical, thermal stability, high thermal conductivity, and one of the best wear resistance [4]. CBN has better chemical stability than diamond for machining ferrum-based alloy [5][6][7][8][9]. Moreover, a monolayer electroplated or brazed CBN grinding wheel has the advantages of high precision machining, with good balance between embedding strength and protruding height, as well as a controllable layout of the abrasive pattern [10,11].…”