Compensation of a ball end tool trajectory in complex surface milling

This work is consecrated to the minimising of machining errors based on a method for the compensation of the trajectory to be machined in hemispherical milling. This compensation is found to be necessary because of the tool deflection due to the cutting forces. In order to remedy to the machining errors, caused by this deflection, a compensation method has been proposed. The latter is inspired from the mirror method, since the compensated position is going to be determined as being the trajectory reflection, deviated onto the mirror. The advantage of this proposed method is that it takes into account the three deflections dx, dy and dz, respectively to the directions X, Y and Z. After that, two-parallel machinings, separated by a groove and achieved absolutely in the same conditions and with the same tool, are carried out, on the same complex part. The first machining is with compensation, but the second is without compensation. The coordinates of the two obtained surfaces are recorded by a 3D measuring machine. The comparison of the two-surfaces shows the presence of an important correction of the tool trajectory, and reveals a similarity between the part obtained by simulation and the one conceived in CAM

Simulation of the deflected cutting tool trajectory in complex surface milling

Since industry is rapidly developing, either locally or globally, manufacturers witness harder challenges due to the growing competitivity. This urges them to better consider the four factors linked to production and output: quality, quantity, cost and price, quality being of course the most important factor which constitutes their main concern. Efforts will be concentrated—in this research—on improving the quality and securing more accuracy for a machined surface in ball-end milling. Quality and precision are two essential criteria in industrial milling. However, milling errors and imperfections, duemainly to the cutting tool deflection, hinder the full achieving of these targets. Our task, all along this paper, consists in studying and realizing the simulation of the deflected cutting tool trajectory, by using the methods which are available. In a future stage, and in the frame of a deeper research, the simulation process will help to carry out the correction and the compensation of the errors resulting from the tool deflection. The corrected trajectory which is obtained by the method mirror will be sent to the machine. To achieve this goal, the next process consists—as a first step—in selecting a model of cutting forces for a ball-end mill. This allows to define—later on—the behavior of this tool, and the emergence of three methods namely the analytical model, the finite elements method, and the experimental method. It is possible to tackle the cutting forces simulation, all along the tool trajectory, while this latter is carrying out the sweeping of the part to be machined in milling and taking into consideration the cutting conditions, as well as the geography of the workpiece. A simulation of the deflected cutting tool trajectory dependent on the cutting forces has been realized

Cross-tolerance to abiotic stresses in halophytes: Application for phytoremediation of organic pollutants

International audienceHalopytes are plants able to tolerate high salt concentrations but no clear definition was retained for them. In literature, there are more studies that showed salt-enhanced tolerance to other abiotic stresses compared to investigations that found enhanced salt tolerance by other abiotic stresses in halophytes. The phenomenon by which a plant resistance to a stress induces resistance to another is referred to as cross-tolerance. In this work, we reviewed cross-tolerance in halophytes at the physiological, biochemical, and molecular levels. A special attention was accorded to the cross-tolerance between salinity and organic pollutants that could allow halophytes a higher potential of xenobiotic phytoremediation in comparison with glycophytes