A jet engine turbine blade is the individual component which makes up the turbine section of a jet engine. The blades are responsible for extracting energy from the high temperature, high pressure gas produced by the combustor. Growing requirements for fuel efficiency now demand tighter tolerances, and many manufacturers have responded by machining oversize forgings to final net shape. The turbine blades are often the limiting component of the jet engine. To survive in this difficult environment, the jet engine turbine blades often use exotic materials like superalloys and many different methods of cooling, such as internal air channels, boundary layer cooling, and thermal barrier coatings.