EFFECTS OF WATER-MIXTURE FILM ON IMPACT CONTACT IN ABRASIVE WATERJET MACHINING

The effects of a water-mixture film adhering to solid materials on the impact contact are examined by employing exact solutions for an inhom ogeneous contact problem and the Hertz impact theory. The elastic modu lus of the water on a surface is assumed to be zero and the modulus of the water-mixture between a water surface and a target material varie s from zero to the modulus of the target material Non-elastic deformat ion is considered based on an energy balance. A new expression of clos ed form for impact force is obtained. The film effect on the impact fo rce is very significant for low impact energy and becomes stable and l ess influential once impact energy increases to a certain value. Exper imental results for quasi-static force are in agreement with the theor etical analysis in which two unknown parameters are ascertained by exp eriments. The minimum effective velocity of garnet abrasives achieved in this work for waterjet machining is consistent with previous result s. Copyright (C) 1997 Elsevier Science Ltd.