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International audience; In this paper, high speed trimming of a multidirectional CFRP using unused and used burr tools is considered in order to investigate the influence of the machining parameters (e.g., feed speed, cutting speed and cutting distance) on the cutting forces, machining temperature, and the machined surface quality. To estimate the effect of the tools’ wear and cutting parameters on the cutting forces and surface roughness, a statistical method (ANOVA) has been used. When considering an unused tool, the recorded temperatures were below the glass transition temperature of the composite material (Tg). In the case of used tools, these temperatures were mostly higher than the Tg. Furthermore, SEM observations of the machined surface showed damaged areas. These areas were wider when the cutting distance increased. Statistical analyses have shown that the machining parameters have a significant influence on the variation of the machined surface quality and the cutting forces.

Titanium and its alloys are attractive materials due to their unique high strength-weight ratio that is maintained at elevated temperatures. Ti-6Al-4V alloy are notorious for their poor thermal properties and are classified as difficult-to-machine materials. Drilling is an important machining process since it is involved in nearly all titanium applications. It is desirable to develop optimised drilling processes for Ti and/or improve the hole characteristics such as hole diameter, circularity and exit burr of currently available processes. Due to the low machinability of the alloy under study, selecting the machining conditions and parameters is crucial. The hole quality, thrust force, torque and exit burr were evaluated at various spindle speeds, feed rates combinations. The optimised parameter is chosen using the multi-objective weighted sum optimisation technique. The tool life for the optimised parameter was studied and the life of the carbide drill was observed to be 140 holes in drilling of titanium.

Experimental and analytical studies were carried out regarding delamination at the hole exit during the drilling of composite structures made of a recent semi-preg called HexFIT® developed by Hexcel composites for resin film infusion (RFI). The plates studied were manufactured in autoclave and in oven. The experimental analysis showed that delamination at the hole exit is influenced by the machining parameters on the one hand and by the composite plate manufacturing process on the other. Following this, empirical models were developed to predict this delamination for each type of manufacturing process and according to the machining parameters. These models gave satisfactory results compared to the experimental values. The maximum relative variation obtained between the values given by the models and those measured by experiments was about 9%. From these empirical models, the critical machining parameters were determined in order to avoid delamination at the hole exit. Critical machining parameters were experimentally tested and their evaluation has shown acceptable results.