Performance Assessment of Surface Treatment with Water Jet in terms of Roughness

摘要

Surface treatment methods based on mechanical tools, sand blasting and flaming lead to undesirable features such as chromatic modifications, production of micro-cracks, mechanical alterations. Water jetting is a relatively new process of stone surface treatment based on the action of very high velocity water jets generated at constant pressure. Water jet treated stone surfaces are of higher level of aesthetical appearance than the other methods It is used to increase the roughness to improve its antislip properties while preserving aesthetic appearance of the stone without having thermal shock, mechanical stress and the production of fumes and dust. Therefore roughness is the most important performance parameters in stone surface treatment with a water jet. Because of this, the purpose of this study is to determine the effects of different operational parameters such as; traverse velocity, standoff distance and pump pressure on performance parameter namely roughness in stone surface treatment with a water jet by using Italian basalt natural stone samples, commercially referred to as Sardinian Basalt. 27 surface treatment tests were performed using the Water Jet Cutting-Surface Treatment Machine with a constant nozzle diameter of 0.3 mm at varying standoff distances (50' 100 and 150 mm), traverse velocities (15, 20,25 m/min) and pump pressures (200, 250, 300 MPa). After each surface treatment, roughness measurements were performed on all of the treated surfaces in two perpendicular directions by using Mitutoyo SJ-400 roughness measurement, equipment. The roughness parameter [absolute deviation (Ra)] was then calculated. Absolute deviation can be defined as the average of the absolute deviations of height from the mean. The data obtained from this study were evaluated graphically and the relationships between operational parameters and roughness values were put forth. As a result of this study, it is observed that operational parameters have direct effects on performance namely roughness in surface treatment with water jet.