A brief review on the status of machining technology of fir-tree slots on aero-engine turbine disk

Abstract

The machining precision and its consistency of turbine disk fir-tree slots have a direct influence on the performance of aero-engine rotor components. However, the structural dimensions of fir-tree slot are small, and the cutting performance of materials is extremely poor, which lead to great difficulty in machining and very few available machining methods. With the application of new materials in the aero-engines, the machining precision and quality requirements of fir-tree slots are further improved. Therefore, many research achievements on the high-efficiency, high-quality and low-cost machining technology of turbine disk fir-tree slots have been obtained. By summarizing and classifying the machining methods of aero-engine turbine disk fir-tree slots, a brief review on the characteristics of different methods are presented in detail, which provide a reference for selecting the appropriate machining method of turbine disk fir-tree slots in the field of aviation manufacturing. Meanwhile, combined with the research and application status of machining technology of turbine disk fir-tree slots, it is presented that multi-process compound machining is an effective method to realize high-efficiency, high-quality and low-cost precision machining of turbine disk fir-tree slots, such as wire electro discharge machining (wire-EDM) and profiled grinding, wire electrochemical machining (wire-ECM) and profiled grinding, wire-EDM and broaching, milling and broaching.

The Review of Current and Proposed Methods of Manufacturing Fir Tree Slots of Turbine Aero Engine Discs

“…Due to high manufacturing costs, new methods are constantly being sought. The most promising new manufacturing methods in recent years are abrasive electrochemical machining (AECM), wire electrical discharge machining (WEDM) and abrasive water jet machining (AWJM) [ 21 , 24 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 ]. The requirements for fir tree disc slot manufacturing can be divided into two groups: requirements concerning machining accuracy and those regarding surface quality, such as surface roughness or the thickness of the white layer.…”

“… Wire electrical discharge machining of turbine disc slots ( a ), WEDM machine tool scheme ( b ) [ 43 , 119 ]. …”

“…For sample 4 (TPX adapted), the thickest recast layer was obtained (up to over 3 μm). A sample with no recast layer is very difficult to produce, especially in the inner radii of the slot profile [43]. In WEDM, the height of the workpiece has the greatest influence on cutting speed, and therefore, on productivity.…”

“…For sample 4 (TPX adapted), the thickest recast layer was obtained (up to over 3 µm). A sample with no recast layer is very difficult to produce, especially in the inner radii of the slot profile [43]. [28].…”

“…Until the WEDM process overcomes the issues of the heat-affected zone (HAZ), it will be utilized mainly for roughing machining. Jianhua et al proposed using form grinding as a finishing process after electrical discharge machining (Figure 39) [43]. [28].…”