Abrasive Waterjet (AWJ) Forces—Potential Indicators of Machining Quality

Abstract

The necessity of monitoring the abrasive waterjet (AWJ) processes increases with the spreading of this tool into the machining processes. The forces produced on the workpiece during the abrasive waterjet machining can yield some valuable information. Therefore, a special waterjet-force measuring device designed and produced in the past has been used for the presented research. It was tested during the AWJ cutting processes, because they are the most common and the best described up-to-date AWJ applications. Deep studies of both the cutting process and the respective force signals led to the decision that the most appropriate indication factor is the tangential-to-normal force ratio (TNR). Three theorems concerning the TNR were formulated and investigated. The first theorem states that the TNR strongly depends on the actual-to-limit traverse speed ratio. The second theorem claims that the TNR relates to the cutting-to-deformation wear ratio inside the kerf. The third theorem states that the TNR value changes when the cutting head and the respective jet axis are tilted so that a part of the jet velocity vector projects into the traverse speed direction. It is assumed that the cutting-to-deformation wear ratio increases in a certain range of tilting angles of the cutting head. This theorem is supported by measured data and can be utilized in practice for the development of a new method for the monitoring of the abrasive waterjet cutting operations. Comparing the tilted and the non-tilted jet, we detected the increase of the TNR average value from 1.28 ± 0.16 (determined for the declination angle 20° and the respective tilting angle 10°) up to 2.02 ± 0.25 (for the declination angle 30° and the respective tilting angle of 15°). This finding supports the previously predicted and published assumptions that the tilting of the cutting head enables an increase of the cutting wear mode inside the forming kerf, making the process more efficient.

Analysis of Several Physical Phenomena Measured on the Metallic Materials Cut by Abrasive Water Jets (AWJ)

“…When using thicker samples, the respective ratio can stay high and does not decrease, whereas when thinner samples are used, the ratio decreases as the traverse speed approaches the limit traverse speed. The results are presented in Figure . 6 in the cited article [25].…”

Notes on the Abrasive Water Jet (AWJ) Machining

“…Each of the norms has been used in a particular part of the previous research and reflected the changes on market. The previous publications with identical metals were aimed at the product distortion in the AWJ cutting [41], the impact of the steel structure on the declination angle [42], investigation of the AWJ cutting forces [43], and the revised theoretical model [44]. The ČSN EN norm is transformed Czech national norm and it describes the metal type, its quality, and strength through the numerical code.…”

“…Studied materials-summary of marking according to all norms used in previous published studies[41][42][43][44].…”

Reduction of Cracks in Marble Appeared at Hydro-Abrasive Jet Cutting Using Taguchi Method

“…A recent research study [13] proposes an approach to the complex process of cutting hard rock, analyzing and evaluating the intensity of the disintegration of abrasive materials in the process of cutting AWJ, during the creation of the abrasive jet. Some current processing models on abrasive water jet machines used in the analysis of the behavior of various materials, including rock type are presented in the papers [14][15][16], but in the field of marble cutting by AWJ process research is limited.…”