Hybrid plasma deposition and milling for an aeroengine double helix integral impeller made of superalloy

Abstract

Superalloy integral impeller is a vital functional component of an aeroengine, but it is very difficult to manufacture if using the traditional five-axis NC machining method because of its complex free surfaces. Lamination deposition technology using high energy beams can overcome these difficulties and can be used to directly manufacture complex superalloy double helix integral impellers. However, subsequent re-machining should be required to guarantee adequate dimensional precision. In this paper, it is proposed to manufacture the superalloy double helix integral impeller using an approach of HPDM (hybrid plasma deposition and milling) which combines plasma deposition manufacturing as an additive technology and milling as a subtractive technique. Compared with the existing RP methods using high energy beams, HPDM solved the key problems of insufficient dimensional precision and surface quality caused by the step effect and lacking of supporting. To demonstrate the effectiveness of the proposed approach, an aeroengine superalloy double helix integral impeller with good performances of dimensional precision, microstructure and mechanics was rapidly manufactured by HPDM.