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Tool life monitoring in end milling of AISI H13 hot work die steel using a low‑cost vibration sensor connected to a wireless system.
(2022) Vianello, Pedro Ivo Alves; Abrão, Alexandre Mendes; Maia, Antônio Augusto Torres; Pereira, Igor Cezar
Machining of complex components with high added value requires the development and implementation of technologies for monitoring the processes outputs and to ensure the performance and reliability of the manufactured part. Cutting tool wear is one of the most relevant variables in machining due to its efect on both the machining cost and quality of the manufactured component. Although tool wear has been extensively investigated for more than a century, the advent of Industry 4.0 has required more accurate and reliable monitoring systems. This work investigates the feasibility of using a low-cost vibration sensor, based on a micro-electromechanical system (MEMS), connected to a wireless data transmission system attached to a rotary tool (milling cutter) for tool wear monitoring when milling annealed AISI H13 hot work die with coated tungsten carbide inserts. A microcontroller with an integrated internet connection connected to a local server through the Wi-Fi network was employed. In order to validate the proposed system, tests were performed comparing its behavior with a conventional piezoelectric sensor in terms of sensitivity to changes in the cutting conditions and tool wear evolution. The results indicated that the proposed system responds satisfactorily to changes in the cutting conditions, with approximately a four-fold increase in the acceleration amplitude when either cutting speed or axial depth of cut were doubled. Although neither the MEMS nor the piezoelectric accelerometer was capable to detect tool wear evolution (considering a tool life criterion VBB=0.3 mm), the RMS value of the signal generated by the vibration sensor based on MEMS is approximately four times higher than that provided by the piezoelectric accelerometer, thus indicating a better representation of the vibration phenomenon resulting from fxing the MEMS on the tool (in contrast to the piezoelectric accelerometer attached to the workpiece).
Dynamic behavior of tapping axial force.
(2021) Pereira, Igor Cezar; Mapa, Lidianne de Paula Pinto; Barros, Thamiris Nogueira de; Fortes, Reinaldo Clemente; Silva, Marcio Bacci da; Guimarães, Gustavo Paulinelli
Background Tapping is one of the processes that most requires attention in the industry, due to the stage in which it occurs and its characteristics. In the case of tapping, it is common to use components and equipment with less rigidity, which com promises the dynamic behavior in several situations and can lead to process distortion or failure. Purpose The objective of this paper is to study the dynamic behavior of tapping in relation to several characteristics of the process. Methods The dynamic behavior of the force signal was used to evaluate the process, varying the cutting parameters and the clamping system of the workpiece. Results The experimental results indicate that the foating system did not present a good dynamic behavior at high cutting speeds, this greater application of vibration is due to the resonance due to the combination of oscillations under forced and natural vibration. Conclusions The natural frequency of the foating fxture system infuenced the behavior of the axial forces. The increase in cutting speed resulted in a direct increase in the axial force vibrations as its frequency came close to the natural frequency of the system. Through dynamic analysis of the axial force signal observed the dynamic characteristics of the process and the machine tool. This allowed the dynamic evaluation of the system through the measurement of force signals generated in the threading process.

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