Abstract—In this paper, an erosion-based model for abrasive waterjet (AWJ) turning process is presented. By using modified Hashish erosion model, the volume of material removed by impacting of abrasive particles to surface of the rotating cylindrical specimen is estimated and radius reduction at each rotation is calculated. Different to previous works, the proposed model considers the continuous change in local impact angle due to change in workpiece diameter, axial traverse rate of the jet, the abrasive particle roundness and density. The accuracy of the proposed model is examined by experimental tests under various traverse rates. The final diameters estimated by the proposed model are in good accordance with experiments. Keywords—Abrasive, Erosion, impact, Particle, Waterjet, Turning. I. INTRODUCTION BRASIVE waterjet (AWJ) machining is a well- recognized technology for cutting variety of materials such as composites and aerospace alloys [1, 2]. In recent years, AWJ technique was used in milling [3] and specially turning operations [4]. In turning operation, the workpiece is rotated while the AWJ is traversed in axial and radial directions to produce the required geometry. Some authors have reported about the volume removal rate [5], surface finish control [6], flow visualization study [7], and modeling of the turning process [8], using AWJ technique. Unlike conventional turning, AWJ turning is less sensitive to the geometrical workpiece profile. This method is not related to length-to-diameter ratio of the workpiece and therefore enables the machining process to turn long parts with small diameter with close tolerances. This process is ideally suitable for machining materials with low machinability such as ceramics, composites, glass, etc. [9]. Useful works by previous researchers have been done which most of them are based on experimental investigations. From a visualization study Hashish reported that the material removal takes place on the face of the workpiece rather than on the circumference of the workpiece [7]. Ansari and Hashish conducted experimental investigations to study various parameters on the volume of material removed in AWJ turning [10]. The results show that Iman Zohourkari is PhD student, Faculty of Mechanical Engineering, K. N. Toosi University of Technology, Tehran, Iran, P. O. Box: 19395-1919, (corresponding author to provide phone: (+98)-915-306-1870; e-mail: iman_zohourkari@engineer.com). Mehdi Zohoor, is associated professor in Faculty of Mechanical Engineering, K. N. Toosi University of Technology, Tehran, Iran, P. O. Box: 19395-1919, (e-mail: mzohoor@kntu.ac.ir). the volume of material removed in AWJ turning is similar to that achieved in AWJ cutting. Zhong and Han [11] studied the influence of variation in process parameters on turning of glass with abrasive waterjet. They reported that lower traverse rate of jet and higher rotational speed of workpiece resulted in lower waviness and surface roughness for turned specimen. Many attempts have been conducted to model AWJ cutting of ductile metallic materials and brittle ceramic materials. However, attempts on modeling of AWJ turning process are very much limited. A semi-empirical model to predict radius reduction in turning using a regression model was presented by Zeng et al. [12]. Based on an empirical approach to model AWJ turning presented by Henning [13], the material removal in AWJ turning process is assumed to be the superposition of volume removed by single particle impacts on the surface of the workpiece. Empirical models do not explain the mechanics of the process. In addition, To determine the exponents and coefficient of the empirical models, the regression analysis should be undergone. An analytical model was suggested by Ansari and Hashish [5] that relates the volume sweep rate to material removal rate. This model could predict the final diameter of specimen in various set of AWJ turning process parameters. Hashish modified his linear AWJ cutting model for AWJ turning [14]. He considered that material is removed from the face of the rotating workpiece and assumed that the total depth of cut consists of cutting-wear depth and deformation-wear depth in turning. To estimate the cutting- wear depth for shallow impact angle zone, Finnie’s theory of erosion was used [15]. To calculate the deformation-wear depth, the Bitter’s theory of erosion was used [16, 17]. This analytical model of AWJ, does not consider the continuous change in impact angle, which is the result of the reduction in diameter of the workpiece. A different approach considering the varying local impact angle presented to predict the final diameter by Manu and Babu [18]. They applied Finnie's theory of erosion to model AWJ turning of ductile materials. However, their model is not able to predict accurate final diameter in various traverse rates. Moreover, at angles near to zero (when the impact angle is very low) it predicts higher volume of removed material. Hence the objective of the present work is to develop and experimentally validate a comprehensive process model for AWJ turning of cylindrical specimens subjected to various traverse rates. An Erosion-based Modeling of Abrasive Waterjet Turning I. Zohourkari, and M. Zohoor A World Academy of Science, Engineering and Technology International Journal of Aerospace and Mechanical Engineering Vol:4, No:2, 2010 169 International Scholarly and Scientific Research & Innovation 4(2) 2010 ISNI:0000000091950263 Open Science Index, Aerospace and Mechanical Engineering Vol:4, No:2, 2010 publications.waset.org/11415/pdf