The chip study can be the simile to the biopsy in the machining process, as it exposes physical phenomena that are generated in the machining process (heat transfer, hardening, phase changes, heat treatments, etc.). These physical phenomena are directly influenced by the cutting parameters applied to the process (feed, cutting speed, and depth). A chip analysis procedure is proposed to estimate some of the physical phenomena generated in the micro-end-milling in a conventional CNC machine on 7075 aluminium and Ti-6Al-4 V titanium alloys. The procedure is composed of hardness tests, metallography, scanning electron microscopy (SEM), and infrared thermography. A softened chip is observed in the Ti-6Al-4 V titanium a hardened one in 7075 aluminium alloy. The chip approach evaluation evidences a great variation regarded to thermal characteristics between micro-machining and meso-machining focused on the scale of the removed layer thickness.