The aim of this work is to analyze the influence of cutting conditions on surface roughness with slot end milling on AL7075-T6. The considered parameters are: cutting speed, feed, depth of cutting and mill radial engage. Response surface models based on experimental data obtained with physical tests have been developed, the authors have performed a consistent set of experimental tests based on design points selected within the four-dimensional design space. Each test has been repeated 3 times to ensure the stability of the collected statistical data. These welldistributed results has been subsequently used to create RS models through approximation techniques based on polynomial and neural network methods and to verify their reliability in terms of correct responses behaviour. The obtained results show that the most significant factors affecting the surface roughness are feed and speed.

No abstract

The HDD process performance and the quality of the formed parts can be influenced by many process variables, such as: fluid pressure, blankholder force, pre-bulging pressure, friction and punch speed [1]. Many studies report how pre-bulging characterization may be done in accordance with the fluid pressure variation [2] or with the maximum bulge height [3][4] value. In this paper, the authors use the maximum bulge height to characterize prebulging levels influence on the process feasibility. The effects of three different pre-bulging levels as well as the traditional geometric and process parameters on a specific component characterized by an inverse drawn shape have been analyzed. In the experimental phase, for each considered process condition the Thickness Reduction (TR) has been detected on the formed component in sixteen different points of interest, to verify numerical and experimental correlation. The good accuracy shown by the numerical model allowed to develop an appropriate numerical campaign to obtain an ANOVA analysis to evaluate the pre-bulging heights influence on TR distribution. The obtained results have shown that the pre-bulging height influences the TR distribution significantly but in a less way than punch radius and blankholder forces profile.

No abstract

Sheet hydroforming has gained increasing interest in the automotive and aerospace industries because of its many advantages such as higher forming potentiality, good quality of the formed parts which may have complex geometry. The main advantage is that the uniform pressure can be transferred to any part of the formed blank at the same time. This paper reports numerical and experimental correlation for symmetrical hydroformed component. Experimental tests have been carried out through the hydroforming cell tooling, designed by the authors thanks to a research project, characterized by a variable upper blankholder load of eight different hydraulic actuators. The experimental tests have been carried out following a factorial plane of two factors, with two different levels for each factor and three replicates for each test with a total of 12 tests. In particular two process parameters have been considered: blank holder force, die fluid pressure. Each factor has been varied between an High (H) and Low level (L). The order in which have been conducted the tests has been established through the use of the Minitab software, in order to ensure the data normality and the absence of auto-correlation between the tests. An ANOVA analysis has been performed, in addition, with the aim of evaluating the influence of process parameters on the thickness distribution of the component, its formability and feasibility. Finally, finite element analysis (FEA) was used to understand the formability of a material during the hydroforming process. In this paper, the commercial finite element code LS-Dyna was used to run the simulations. A good numerical – experimental correlation has been obtained.