The theory and practice of abrasive water jet cutting

Abstract: Abrasive Water Jet (AWJ) has grown to be an important industrial tool during the last decade. A great deal of effort has been put into describing the process. However, many of the most fundamental aspects of the process are still not fully understood, or described, and many questions have been left unanswered. The thesis is divided into three sections:
Section A introduces the AWJ technique by a discussion of the technical and commercial strengths and weaknesses of AWJ cutting as compared to laser cutting. The paper presented shows how and when the two techniques compete, and when they are complementary. The economic comparison is based on a market survey where a product was priced by companies working with AWJ and laser cutting. Section B addresses two engineering problems; the piercing of start-up holes and the cutting of sharp corners with AWL The papers presented discuss the techniques used in practical cutting today and their limitations. Improvements of the common practice, which have led to substantial cost savings, are presented. Each paper ends with straight forward guide-lines for users. Section C presents the results of three scientific projects. The results from the engineering investigations revealed a strong con-elation between the geometry of the cut front and the cutting performance. This finding lead to an in depth investigation of the cut front geometry and the related material removal process. Various techniques were used to establish an understanding of the material removal mechanism and the importance of the cut front geometry. It was found that the material removal mechanism is not a combination of periodic and random components (as other workers believed) but could be described by a self organised criticality model. It was also established that the cut front geometry has an important role in determining the efficiency of the process.