AERMS Signals Research Articles

Monitoring the abrasive waterjet drilling of Inconel 718 and steel: a comparative study

This paper presents an experimental study on abrasive waterjet (AWJ) drilling of Inconel 718 and AISI 1040 steel, with an aim to understand the AWJ hole drilling performance and to investigate the process monitoring strategy by using acoustic emission (AE). In the experiments, pressure levels were set from 200 to 350 MPa at intervals of 50 MPa, and drilling time between 5 and 30 s at intervals of 5 s. It is found that the hole depth increases along with the drilling time at a slowing down penetration rate. A higher pressure results in a higher penetration rate. While there exists a direct influence of the material property on the drilling efficiency, it has limited significance with regard to the diameter of the hole produced. AE-RMS signal is demonstrated to be able to reflect the decreasing trend of the penetration rate and the influence of the pressure. A strong correlation between the penetration rate and AE-RMS values in AWJ hole drilling is shown through correlation analysis. The AE-RMS is also substantially affected by the material properties. A discrepancy of the AE-RMS under similar condition may suggest an anomaly in this cutting run.

A method to determine the grinding wheel's topography based on acoustic emission

A method for determining the topographic characteristics of a grinding wheel is developed based on acoustic emission (AE) technology. For implementing the procedure, an AE monitoring system was integrated in the CNC of a grinding machine in order to detect a precise reference position on the grinding wheel’s periphery, allowing an AE online mapping procedure to characterise the topography of the grinding wheel. The AE mapping procedure is carried out by acquiring the AERMS signals originated from the minimal interferences between grinding wheel and an AE instrumented diamond tip. The interferences are in the elastic deformation range. The obtained AE map of the grinding wheel’s topography is compared with the grinding wheel’s imprint topography as well as to a previous developed model aiming at the results validation. The AE mapping procedure is sensitive to different grinding wheel’s topographies caused by changes in the dressing parameters and the inherent grinding wheel’s wear.

A Quick-Test Method to Determine the Grinding Wheel Topography Based on Acoustic Emission

A quick-test method for the determination of the topographic characteristics of a CBN grinding wheel is developed based on acoustic emission technology. For implementing the strategy, an acoustic emission (AE) monitoring system was integrated into a 3 axis CNC grinding machine. A computer with specific software allows the signal acquisition and visualization of the AERMSsignals, which are originated through interferences between the grinding wheel and dressing tool in a range of a few micrometers. The acquired AERMSsignals from these interferences are used in order to establish an on-line map from the grinding wheel periphery, indicating the active cutting grains during the contact amid grinding wheel and dressing tool. The implementation of such activity supported by AE has led to satisfactory results regarding the required time to evaluate the strategy as well as the verified correlation with different grinding topographies caused by changes in the dressing parameters.