Échauffement généré dans les plaques d'aluminium 2024 lors de l'usinage mécanique de la surface : application à l'usinage des poches sur revêtement du fuselage

Abstract

In the aircraft industry, which widely consume aluminum alloy to constitute the aircraft structure, end-milling is mainly used to produce the desired components. However, in order to adjust this mechanical process, several complex factors occurring during the cutting stage have to be considered, making the process development difficult, especially compared with the chemical milling. Following of the literature review, the optimization and control of milling process ultimately have to build through a heat analysis and comprehension. In other words, to efficiency and robustness end, controlled temperature level is an important issue, which is why the thermal aspect of cutting is a traditional concern in machining process and so often takes part of experimental investigation. In order to investigate the influence of cutting parameters, a measurement device associated with embedded thermocouples at stationary positions in subsurface have been used. By that method, the local temperatures have been recorded through thermocouples located along the line forming by the tool-path and keeping a constant distance beneath the machined surface. Measurement results, based on the peak value recorded while the cutting edge cross over a thermocouple, have clearly proved the variability of internal-temperature during milling experiments, undertaken under varying factors. Data collected throughout the milling experiments, using a full factorial array, indicated that the work-piece internal-temperatures values rise with the decrease of feed rate. The effect of the chip thickness has one of the most significant influences on subsurface temperature recorded, more than the cutting speed. The optimum milling condition is achieved for low depth of cut, high cutting speed and a feed per tooth equal at least to 0.005’’, in trying to avoid cornerisation with small radius. Also, in regard to investigations carried out, the partial radial tool engagement (60% of tool diameter) shows a substantial decrease compared with the full radial diameter engagement in material. On another point concerns the heterogeneity of measured internal-temperature. Noted through measured position, an increase of the internal-temperature is indicated while the cutting tool is moving into work-piece from the left part (beginning of the cutting stage) to the middle line of the tool-path. This last observation allows inferring that the uncut chip thickness is one of the most influent factors on the subsurface accumulated temperature from the thermal flux transferred during the tool path.

Date	24 Sept 2015
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Jean-François Chatelain (Supervisor) & Marek Balazinski (Co-supervisor)