The New Jersey Institute of Technology's
Electronic Theses & Dissertations Project

Title:	Investigation of the striation formation in the course of abrasive waterjet cutting
Author:	Chao, Jo-fei
View Online:	njit-etd1993-052 (xvii, 112 pages ~ 3.3 MB pdf)
Department:	Department of Mechanical and Industrial Engineering
Degree:	Doctor of Philosophy
Program:	Mechanical Engineering
Document Type:	Dissertation
Advisory Committee:	Geskin, E. S. (Committee chair) Gordon, Eugene I. (Committee member) Herman, Harry (Committee member) Leu, M.C. (Committee member) Levy, Nouri (Committee member)
Date:	1993-01
Keywords:	Water jet cutting. Nozzles. Surface (Technology)
Availability:	Unrestricted
Abstract:	The principal defect of the surfaces generated by abrasive waterjet machining is excessive waviness (striation). The existing theories of striation formation are not adequate to explain this phenomenon. The presented study is concerned with the development of an understanding of the mechanism of striation formation. A spectral analysis of temporal process and spatial surface characteristics demonstrated that the striation is caused by nozzle vibration that is due to the conditions of the motion control of the nozzle. This enabled us to discover a means for improving the surface finish. From a study of the surface spectra, it was found that the amplitudes of the striation marks could be expressed as a second degree polynomial function of the distance from the top of the workpiece. The effects of the jet pressure, cutting speed, and workpiece material on the surface topography were also investigated. The acquired information was used to construct a model for the simulation of surface topography.