Research on the design and cutting performance of a novel BTA boring tool intended for machining of nickel-based superalloys

With the rapid development of the advanced technology field, extremely high requirements have been imposed on the straightness of key deep-hole components with large depth-to-diameter ratios. These components require precise machining via the BTA boring method to attain the desired accuracy. However, the challenging characteristics of the nickel-based superalloy GH4169, which is commonly used in these components, contribute to significant tool wear. This is further compounded by the slender drill rod and poor stability of the tool, resulting in unsatisfactory straightness. To address these challenges, this paper adapts tool materials and designs a novel BTA boring tool structure. Experimental investigations on BTA deep-hole boring are conducted to evaluate the cutting performance of the designed BTA boring tool, exploring the influence of process parameters on machining quality and analyzing the mechanism of surface creation of the hole wall. The research results indicate that the K20 carbide cutting insert exhibits exceptional adaptability for machining GH4169. Reducing the feed rate can help decrease the diameter runout, but it may result in severe wear on the tool due to prolonged contact with the workpiece. This wear can be more detrimental than that experienced at a higher feed rate, ultimately degrading the straightness. The designed BTA boring tool achieves a straightness of 0.016/900 mm for machining the deep hole structure of GH4169. The research findings provide valuable insights for optimizing tool design, recognizing the boring mechanism, and refining process parameters, contributing to enhanced machining quality of deep-hole boring.