Revised Model of Abrasive Water Jet Cutting for Industrial Use

Abstract

Research performed by the author in the last decade led him to a revision of his older analytical models used for a description and evaluation of abrasive water jet (AWJ) cutting. The review has shown that the power of 1.5 selected for the traverse speed thirty years ago was influenced by the precision of measuring devices. Therefore, the correlation of results calculated from a theoretical model with the results of experiments performed then led to an increasing of the traverse speed exponent above the value derived from the theoretical base. Contemporary measurements, with more precise devices, show that the power suitable for the traverse speed is essentially the same as the value derived in the theoretical description, i.e., it is equal to “one”. Simultaneously, the replacement of the diameter of the water nozzle (orifice) by the focusing (abrasive) tube diameter in the respective equations has been discussed, because this factor is very important for the AWJ machining. Some applications of the revised model are presented and discussed, particularly the reduced forms for a quick recalculation of the changed conditions. The correlation seems to be very good for the results calculated from the present model and those determined from experiments. The improved model shows potential to be a significant tool for preparation of the control software with higher precision in determination of results and higher calculation speed.

Analyses of Vibration Signals Generated in W. Nr. 1.0038 Steel during Abrasive Water Jet Cutting Aimed to Process Control

“…The speeds were increasing, they were designed to produce kerfs with degrading quality of the cut ( Figure 2 ). The measurement cycle was repeated on the same material for all measured thicknesses, the respective traverse rates were recalculated for each thickness according to the Hlaváč’s model, recently updated in [ 28 ]. Based on this model classification, the data were divided into four cutting qualities ( Table 3 ).…”

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].…”

Influence of Local Temperature Changes on the Material Microstructure in Abrasive Water Jet Machining (AWJM)

“…Various approaches were used to describe and make predictions about the process. A simplified model for calculating the maximum cutting speed, proposed by Hlaváč, and updated in [ 12 ], can be written as Equation (1): where: —maximum cutting speed, (m/s); —coefficient taking into account the abrasive mass flow rate and the abrasive quality, (−); —nozzle orifice diameter, (m); —density of the abrasive water jet (treated as a homogeneous liquid), (kg·m −3 ); —pressure of the abrasive water jet according to Bernoulli’s principle for a liquid with predetermined density and velocity, (Pa); —damping coefficient for the abrasive water jet flowing between the nozzle and the workpiece surface, (m −1 ); —standoff distance (distance between the nozzle and the workpiece surface), (m); —coefficient of velocity loss (a decrease in the water flow rate on impact with the workpiece surface), determined through experiments, (−); —material thickness, (m); —material density, (kg·m −3 ); —material strength, (Pa); and —minimum cutting speed, (m/s); it is generally assumed that , where , (m), is the average abrasive grain size in the mixing head and the mixing tube.…”

“…Various approaches were used to describe and make predictions about the process. A simplified model for calculating the maximum cutting speed, proposed by Hlaváč, and updated in [12], can be written as Equation (1):…”