A Reconfigurable Flexible Fixture with Surface-Contact Clamping for Irregular Thin-Walled Parts

A reconfigurable, flexible, and modular fixture system is proposed for the milling of irregular thin-walled parts, which are commonly encountered in aerospace applications and require high machining precision. Conventional universal fixtures often fail to provide adequate support for such components, particularly in terms of clamping stress, operational efficiency, and vibration control, while dedicated fixtures tend to be costly. The developed design, guided by the Theory of Inventive Problem Solving (TRIZ), incorporates six independently adjustable jaws. These jaws can be reconfigured according to the part geometry, enabling flexible adaptation to different workpiece shapes. Through a pre-processing step applied to the jaw surfaces, the fixture achieves area-based contact with the part, replacing the line-contact mode typical of conventional setups. This improves clamping stability, reduces localized stress, and mitigates vibration during machining, thereby contributing to improved accuracy. In addition, once the jaw positions are determined based on a trial cut of the initial workpiece, they remain fixed for subsequent parts, streamlining the setup process. Machining trials showed that surface-contact clamping reduced roundness tolerance from 0.0523 mm to 0.0287 mm, flatness from 0.0106 mm to 0.0036 mm, and parallelism from 0.0190 mm to 0.0105 mm. The resulting fixture offers a combination of structural simplicity, adaptability, cost-effectiveness, and machining reliability, making it suitable for thin-walled components in small-batch or varied production contexts.