Development of an Assistance and Control System for Waterjet Cutting of Free-Form Workpieces

The process accuracy when cutting free-form parts using waterjet technology depends on several factors, including various preparatory tasks, such as defining the workpiece coordinate system. Some manual procedures for determining it are already used. Those methods are based on the usage of laser pointers or dial gauges, which are fixed on the machine head. As a computer-aided alternative, measuring probes can be used to define the zero point offset of a workpiece, or to compare its dimensions to the ones predefined in the CAD data. When processing flat parts, optical systems can be used for layout alignment on the blank material. In order to redefine how the workpiece coordinate system is measured on a waterjet cutting machine, a new assistance and control system is being developed. It features an optical system that scans marked clamping and positioning devices whose relative positions to the machined part are precisely defined. By returning data about their location to the control unit, the workpiece coordinate system can be calculated. This paper describes the steps necessary for developing such a system, as well as the design and work principle of a fixturing system that supports the clamping and positioning of such free-form workpieces.