An Investigation into the Comparative Costs of Additive Manufacture vs. Machine from Solid for Aero Engine Parts

An overview of the relative economics of producing a near net shape by Additive Manufacturing AM processes compared with traditional machine from solid processes MFS is provided. A relationship is developed to estimate the specific cost of AM material required to achieve a typical 30 saving over conventional MFS techniques. The use of AM techniques are shown to be advantageous for parts which have a high buyfly ratio, have a complex shape, have a high cost of raw material used for machining from solid, have slow machining rates and are difficult and expensive to machine. The specific cost of material deposited by additive manufacturing systems required to give a 30 saving over conventional Machine from solid techniques is estimated for a typical aerospace alloy over a range of buyfly ratios. The specific costs of a typical aerospace alloy deposited by present and future additive manufacturing systems are estimated and compared with the required specific costs estimated above. It is concluded that additive manufacture is commercially viable using present additive manufacturing systems for components with a buyfly ratio of about 121. For projected future additive manufacturing systems economic production of components with a buyfly ratio of about 3 should be feasible.