Process Monitoring of Abrasive Waterjet Formation

Abstract

Difficult to machine materials require innovative processing solutions for a stable and high quality contouring process of complex forms. Abrasive waterjet cutting gains in importance due to the continuous development of novel high performance materials and multi-material components. A reliable process monitoring during the machining operation becomes essential to avoid waste production. However, the measurement of the process conditions during abrasive waterjet cutting is difficult based on the rough environment inside the machining zone. In this paper appropriate methods for in-process monitoring of the jet conditions, in particular the critical nozzle wear as well as other process output parameters are being tested, discussed and classified.

A Review of Waterjet Cutting Research towards microAWJ and the Definition of the Waterjet Digital Twin

“…The waterjet focusing tube is a critical component, as its fast wear progression requires constant human supervision for promptly detecting detrimental effects on the cutting performance [90]. Reference papers can be found in the literature on AWJ process monitoring [91], focusing on tube erosion [92][93][94] and operating costs [95]. The research reported in [96] described an innovative approach based on the focusing tube operational vibration for inline monitoring of the wear progression of a waterjet focusing tube by means of an accelerometer installed on its tip.…”

Nozzle Condition Monitoring System Using Root Mean Square of Acoustic Emissions during Abrasive Waterjet Machining

“…Kovacevic developed a sensor that directly detects nozzle wear during AWJ machining [24], and Kovacevic and Zhang described an online monitoring system using the AWJ acoustic signal and nozzle wear estimation employing an autoregressive moving average (ARMA) spectrum [25]. Putza monitored nozzle wear and abrasive grain clogging by measuring the temperature of the waterjet head, nozzle sounds and vibration, and changes in flow rate, and various sensors were used to assess temperature, sounds, jet acceleration, and flow [26]. Prabu obtained acoustic signals at various abrasive feed rates and pressures and associated these with the extent of nozzle wear as the AWJ parameters varied [27].…”

Operational vibration of a waterjet focuser as means for monitoring its wear progression

“…The aerospace, defense and automotive industries constitute the largest end-user segments of AWJC [6]; here, several features contribute to provide an edge with respect to alternative manufacturing technologies, notably its lower initial investment, the absence of a heat-affected zone on the workpiece, no limitations in shape complexity, no mechanical contact with physical tools, narrow kerf (down to 0.3 mm), negligible blurs, good edge sharpness [5] [7]. However, tight quality standards of said reference sectors, as well as high operating costs of AWJC [6], pose a challenge to machine builders for improving the automation and stability of their processes; on this regard, their efforts have been pushed in the direction of delivering enhanced components, more robust and reliable [1], as well as developing new techniques for process monitoring [8]. The improvement of AWJC automation constitutes the driver of the present research, which lies in the field of vibroacoustic process monitoring as means for extracting relevant information that could be beneficial for the purpose.…”