A Flexible Localization Method of Multi-Constrained Free-Form Surface Based on the Profile Curves

Abstract

The precision forming process is currently used for many difficult-to-cut parts such as aero-engine blades. However, satisfying the tolerance requirement of the forming accuracy is difficult. Thus, precision machining is used to ensure final accuracy of the part. The error of the near-net shape caused by the thermal process cannot be ignored in the machining process. If the cutting tool path is generated in terms of the design blade model, it would be too difficult to satisfy the material allowance and tolerance requirement of the design blade. In this paper, we propose a new flexible localization method to reconstruct a to-be-cut surface which improves the qualification rate. In this method, the tolerance and material allowance requirements are transformed into optimization constraints. Furthermore, the profile curves of the to-be-reconstructed blade surface are converted into the optimization variables. The material allowance distribution of the to-be-reconstructed surface needs to be as uniform as possible. Through this optimization, the profile curves of the blade surface at the specified height are obtained and used to evaluate the to-be-cut blade model. Finally, a typical compressor blade model is used to verify the proposed method. The results show that the approach can meet the tolerance requirements and ensure sufficient material allowance for the near-net shape blades.

Keywords

• profile curve
• tolerance
• hybrid constraint
• localization
• optimization