The quality of metal products bent on CNC machines

The world market must provide products, that adapt to customer needs, which implies large investments and long-term employments. The way of thinking of the buyers is anticipated by the producers. The paper presents studies and researches in the field of bending of metal parts with thickness of 2 mm. The studies and researches have offered answers to the many problems that companies face. The quality of the products is the main attribute. In the first stage of the research, the unfolding of the flat parts was determined. A bending coefficient Kî was introduced in the calculation of the plane parts. The quality and precision of the parts was influenced by different variables: the temperature variation during the processes of punching and bending, vibrations of machines, tool usage, tolerance between the surface of the bending tools, their usage and the roughness of the metal sheet, the type of the material, the chemical composition, the degree of complexity and the number of bends, the movement between the piece and punching or bending tools and other variables. The calculation of the unfolded (flat parts) was a priority, as it must include the deformations caused by the bending operations. Bending coefficients K î must compensate for deviations from the final dimensions of the metal products, because of the many variables that can adversely affect their execution. The quality and precision of the bent pieces, with a thickness of 2 mm, is the objective of this paper. The bending coefficient was obtained through experimental tests and measurements.