Influence of Rotational Speed on Accuracy in Measuring MIRS of Aerospace Aluminum Alloy by Incremental Hole-Milling Method.

Abstract

The incremental hole-drilling method is widely used to measure residual stress distribution versus depth. In this study, a two-flute carbide end mill that was 1.5 mm in diameter operated at different rotational speeds, used to create a hole that was 2.0 mm in diameter through orbital technology milling, were used to measure machining-induced residual stress (MIRS). Additionally, a finite element model was developed to calculate distortion, with MIRS as the input. A 25 × 25 × 1 mm³ thin sample containing a machining surface was cut free from large samples by a wire electrical discharge machining after milling, and distortion was measured by a 3D profile meter. It can be concluded that the calculated maximum distortion on one of the diagonals can reach 89% of the measured maximum distortion when the rotational speed is more than 20,000 rpm, and the deviation in the measured MIRS can be controlled within 35 MPa. The shear stress increases rapidly by 63% when the rotational speed is less than 10,000 rpm.