Papers by Author: Michele Monno

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Authors: Gaetano M. Pittalà, Michele Monno
Abstract: The machining of titanium alloys is critical also because of high temperature reached at the tool nose. The temperature of the cutting tool affects the tool life and, in order to decrease the temperature, cutting speed is reduced. The prediction of temperature can allow designing the cutting process, in terms of cutting parameters, or make the best selection of the cutting tool, with reduced experimental effort. The rheological model is an important issue in the FEM simulation of cutting in order to achieve a good accuracy, In this paper the milling operation will be considered. This is very common in manufacturing and, often, it represents the last operation, determining the final product quality. Cutting forces, measured by dynamometer table, and temperature, measured by infrared camera, have been recorded during milling tests. The infrared camera captures a part of the workpiece close to the cutting edge. First the material model has been set up considering only cutting forces; next, a sensitivity analysis about the material model parameters has been performed in order to assess the influence of temperature in the determination of the material parameters.
Authors: Massimiliano Annoni, Michele Monno
Abstract: The internal geometry of water jet orifices is important to determine water velocity and structure of the jet: the geometrical features of orifices, such as diameter, rounding of the entrance edge, taper angle of internal walls and so on, play an important role under the fluid-dynamic point of view and, consequently, on water velocity and jet behaviour in air, which are responsible for the available value of specific power on the workpiece. The aim of this study is to experimentally evidence possible differences among performances of orifices coming from different manufacturers in order to point out the effects of orifices geometrical features on water velocity and cutting capability in case of abrasive water jet cutting of Aluminium.
Authors: Riccardo Bini, Michele Monno
Abstract: A numerical model of the electric arc is coupled to a model for the convective flow in the molten pool of a stainless steel sheet during a stationary TIG welding process. This approach allows us to predict the shape of the bead, which is determined by the balance between the Marangoni forces on the free surface and the radial drag from the arc jet impingement. The surface tension of the molten steel is greatly influenced by its temperature and sulphur content, as experiments showed very different bead shapes associated to the same welding parameters. We simulate three sulphur contents, namely 10 ppm, 40 ppm and 100 ppm, showing their effects on the velocity and temperature distributions in the molten pool. A transition between drag-dominated and surface tension-dominated pools is found at a sulphur content of few dozens, in agreement with previous experimental observations.
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