Virtual Models (VMd), Virtual Machines (VMn) and Virtual Processes (VP) are becoming more and more useful tools in manufacturing design, research and development of products. They give possibility to investigate manufacturing and production problems prior to building a physical model or prototype of the machine. Virtual Machines and Virtual Processes are technologies used in the design of machining equipment and in looking at production processes. They consist of a group of recently developed techniques and approaches that allow the construction of machine computer models and the simulation of the fabrication process. What makes this group of manufacturing technologies special is that they allow the checking of machining and production parameters before actual prototypes and their specific tooling are manufactured. The possibility of using these virtual manufacturing techniques could result in great savings of both time and money. In general, virtual manufacturing promises shorter design cycles with more design iterations, leading to an optimal design and better use of resources. The end goal of any virtual manufacturing is to produce a virtual model of a machine that will virtually make the part from its database file containing the geometrical description of a physical object in terms of pre-defined geometric entities. The actual manufacturing hardware provides the physical means to machine the part, which Virtual Machining allows making the as a computer model. Special software is employed to bridge the gap between the CAD data and the virtual manufacturing system. Such software should control various parameters such as the rate at which the positioning system proceeds, the tool path, the thickness of the layer of the material for removal and/or length of the path, the slice length, and others. Virtual manufacturing provides a means of motion control and easy manipulation of various manufacturing hardware. The methods and software described in this paper allow the creation of different kinds of milling and grinding machines which are later compared with the actual existing machines and the parts produced by them. Three virtual systems are presented in this paper. One system was compared to the actual system operating in the CAD&CAM and Expert Systems Laboratory, and another was designed for stereoscopic view experiment. The third is a new machine that is in the design process. Also some examples of workpiece finish produced by virtual machining are described. The work presents an effort to extend virtual manufacturing techniques in design, testing demonstration and manufacturing equipment and processes as well as the teaching of design and manufacturing. The work was conducted at the University of Connecticut using Silicon Graphics systems equipped with inventor, GL library and C compilers.
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