Matylda Floren MT2403, pp. 38. ING/School of Engineering, 2011.
Correctly setting cutting parameters in abrasive waterjet cutting affects both the cost of the process and the quality of separating cut. This thesis report presents the summarized results of work concerning methods for performance evaluation in abrasive waterjet cutting as well as the influence of process parameters on the machinability number calculations. Several series of experiments were set up both for finding the most reliable test method and for examining the variations within abrasive waterjet cutting process and their influence on machinability number. Five known test methods were examined, evaluated and ranked according to their ease of use as well as ability to characterise waterjet process. This thesis presents the one that can be used for all types of materials and gives the most reliable results. Another one of the presented test methods is called piercing and is under development at Swedish Waterjet Lab. In this work it is only preliminary evaluated but it is clear that piercing has great potential although still needs further improvements.
The part to be cut is characterized by a particular machinability number that may not be known for a certain material or may need to be evaluated. That number is not a constant and finding the most proper machinability number is very important for correctly setting cutting parameters. This work describes machinability number variations depending on type of material, pressure variations, orifice and focusing tube diameters as well as abrasive mass flow.
The result of this thesis is presenting an optimization model for abrasive waterjet cutting, a most reliable test method and how to find the proper machinability number for a particular material.