IN-SITU INSPECTION OF TURBINE DISKS FOR SURFACE DEFECTS**

Pratt & Whitney Canada在涡轮机盘的制造中使用电火花线切割（WEDM）以达到非常高的公差。磁盘表面的异常是由人工检查的，小到毫米级。 该项目旨在开发一种动态气动传感器，可以帮助自动化这一检测过程。 这种传感器系统将是气动测量技术的动态等效物，气动测量技术长期以来一直用于工业中的微小位移的静态/准静态测量。 该设备本身将包括一个敏感的压电晶体压力传感器，测量通过喷嘴撞击到被检查工件上的空气射流上的背压。 表面的变化会导致测量的背压发生变化。该项目的挑战在于定制气动传感器的几何形状，以抑制固有噪声并调整其动态性能，使其足够灵敏，能够以最小化检测磁盘所需时间的相对速度稳健地检测和量化感兴趣的表面异常。 气动传感器的一个主要优点是，从喷嘴喷出的空气可以清除被检测表面上的任何碎屑或切削液，从而使其能够在WEDM机床中原位应用。喷嘴尖端还可以具有弯曲的几何形状并且直径为亚毫米，这允许其在叶片保持槽的狭窄范围内使用。** 该项目的交付成果包括：（1）一个原型气动传感器，其几何形状经过优化，可检测和量化线切割表面的表面异常;以及（2）适当处理背压信号所需的任何数据分析技术。 通过提高检测质量和降低检测成本，拟议的工作对于PWC保持其在航空发动机行业的领导地位非常重要，并有助于提高其在这个研究竞争市场中的市场份额。

Pratt & Whitney Canada uses wire electrical discharge machining (WEDM) in the manufacture of turbine disks to very high tolerances. The disks are inspected manually for surface anomalies down to sub-millimetre scales. This project aims to develop a dynamic pneumatic sensor that can help automate this inspection process. Such a sensor system would be the dynamic equivalent of the pneumatic gauging technology that has long been used in industry for static/quasi-static measurement of fine displacement.** The device itself would consist of a sensitive piezo crystal-based pressure sensor measuring the back pressure on an air jet impinging through a nozzle on to the workpiece being examined. Variations in the surface would cause changes in the back-pressure measured. The challenge in this project is to tailor the geometry of the pneumatic sensor with a view to suppressing the inherent noise and tuning its dynamic performance, to render it sensitive enough to robustly detect and quantify surface anomalies of interest, at a relative speed that minimizes the time required for inspecting a disk.** A key advantage of the pneumatic sensor is that the air issuing from the nozzle can remove any debris or cutting fluid off the surface being inspected, which enables its in-situ application in a WEDM machine tool. The nozzle tip can further be of a curved geometry and be sub-millimetre in diameter, which allows for its use within the narrow confines of blade retention slots. ** The deliverables in this project are: (1) a prototype pneumatic sensor with the geometry optimized to detect and quantify surface anomalies in WEDM-ed surfaces, and (2) any data analysis techniques required to appropriately process the back-pressure signal. By both improving the quality of inspections and reducing their cost, the proposed work is important in enabling PWC maintain its leadership position in the aero-engine industry, and help increase its market share in this research competitive market.******************