Construction of digital twin for clamped near-net-shape blade in adaptive manufacturing

Abstract

The near-net-shape engine blade body has already achieved design accuracy after blanking process, while the leading and trailing edges (LE/TE) require further CNC machining. When a blade blank with a thin-walled structure body is formed, the forming deformation caused by stress, temperature and pressure cause the design LE/TE profile to mismatch with the blank body. To solve the mismatch, the LE/TE design model is modified to an adaptive model that matches the deformed body and meets the design requirements for aerodynamic performance. However, the clamping deformation occurs when clamping a formed blank with a design fixture, making the adaptive model unsuitable for guiding the machining of the blank. This paper provides an innovative modelling method to construct a clamped adaptive digital twin (CADT). With the spring-back after clamp release, the profile of the blade machined by the CADT will be consistent with that of the adaptive model. A CADT is constructed for a large-sized near-net-shape fan blade blank. The maximum clamping deformation of the blank is over 0.44 mm, while the average relative error of the machined profile to adaptive model is only 0.49 %. The results show that the proposed method can accurately and efficiently construct a CADT to guide the finishing of a near-net-shape blade.