Carbon Fiber Reinforced Plastics (CFRP) is an encouraging material for aerospace and automotive industries due to its light weight and high strength. Aerospace parts require precise dimensional tolerance and high machined surface quality for safety and reliability. Routing process is needed to produce satisfactory dimensional accuracy of CFRP parts. Machining defects of routing process are related to the cutting mode with respect to cutting angle and bonding strength between carbon fibers and polymer matrix. When the polymer matrix is transformed from polymer to amorphous state, bonding strength is declined. Therefore, cutting temperature is a critical parameter for CFRP machining process because glass transient temperature is relatively low. In this paper, cutting temperature was measured using thermal imaging camera. Machined surface roughness and maximum fiber pull-out depth were analyzed with respect to feed, spindle speed, and laminate structure.

Titanium alloy has been widely used in the aerospace industry because of its high strength and good corrosion resistance. During cutting, the low thermal conductivity and high chemical reactivity of titanium generate a high cutting temperature and accelerates tool wear. To improve cutting tool life, cryogenic machining by using a liquid nitrogen (LN2) jet is suggested. In cryogenic jet cooling, evaporation of LN2 in the tank and transfer tube could cause pressure fluctuation and change the cooling rate. In this work, cooling uniformity is investigated in terms of liquid nitrogen jet pressure in cryogenic jet cooling during titanium alloy turning. Fluctuation of jet spraying pressure causes tool temperature to fluctuate. It is possible to suppress the fluctuation of the jet pressure and improve cooling by using a phase separator. Measuring tool temperature shows that consistent LN2 jet pressure improves cryogenic cooling uniformity.