Experimental investigation of feed rate limitations on high speed milling aimed at industrial applications

This paper presents an experimental investigation on feed rate [mm/min] limitations when milling free form surfaces, commonly found in dies and moulds, applying the high speed cutting technology-HSC. The results appoint feed rate as the bottleneck to achieve the real benefits of HSC in terms of machining time, surface quality and process stability. That is due to unwanted large variations on the initially programmed feed rate, mainly when milling free form surfaces. These “ups” and “downs” on feed rate result in several setbacks for the machining process itself and it can be found even when using a suitable HSC milling machine available in the market. This paper addresses some of the causes for feed rate variations and evaluates an alternative approach to describe a tool path using spline polynomial technique. In order to focus industrial applications, all equipment, materials and software used are accessible in the market. The milling experiments were accomplished on a high-speed milling machine controlled by an open architecture CNC and a high-end CAD/CAM software was used. A 3D free form workpiece was designed and a real-time monitoring system was developed to investigate the feed rate variations during milling operation. The surface quality after milling and the machine tool/CNC performance were also assessed.

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