Advanced ceramics are widely used in industry due to their unique properties. However, the machining of ceramic components by conventional methods is difficult due to their high level of hardness and brittleness. In this sense, laser beam machining (LBM) is presented as an alternative to conventional methods, enabling the machining of workpieces through more accurate and less invasive techniques. Despite the advantages of laser machining, the process still needs to be studied in detail, as advanced ceramic machining is considered a stochastic process. Thus, real-time monitoring systems are required in order to optimize the ceramic laser machining. Therefore, this paper proposes a novel method for monitoring the cutting kerf in the laser cutting process of ceramic components using a low-cost piezoelectric transducer (PZT) and digital signal processing. Tests were performed on the surface of an alumina ceramic workpiece under different machining conditions. The cutting kerf was measured by a digital microscope and the raw signals from the PZT transducer were collected at a sampling rate of 2 MHz. Time domain and frequency domain analyses were performed in order to find a frequency band that best correlates with the process conditions. Finally, a linear regression was calculated in order to correlate the PZT signal and the measured kerf. The results showed that the piezoelectric transducer was sensitive to the acoustic activity generated during the process, allowing the real-time monitoring of the cutting kerf. Thus, the approach proposed in this paper can be used efficiently in the monitoring of the laser cutting process.

Resumo: As cerâmicas avançadas são muito utilizadas em diversas aplicações industriais devido às suas propriedades. No entanto, a usinagem de componentes cerâmicos é muito difícil por causa da sua alta dureza e fragilidade. O presente trabalho apresenta a utilização de um diafragma piezelétrico de baixo custo no monitoramento da largura do dano no processo de usinagem a laser de cerâmicas avançadas. Os ensaios foram realizados para diferentes condições de corte, sendo os sinais coletados por um sistema de aquisição de dados. O valor médio quadrático foi obtido a partir do sinal filtrado em uma determinada banda de frequência previamente selecionada. Os resultados demonstraram que o transdutor pode ser usado eficazmente para o monitoramento do processo de corte a laser.