Online alignment method for angular direction of dovetail-shaped mortise of turbine disc

The invention discloses an online alignment method for the angular direction of a dovetail-shaped mortise of a turbine disc, and belongs to the field of numerical control machining. The method comprises the following steps: firstly, clamping a turbine disc on which all dovetail-shaped mortises are processed on a five-axis machine tool, enabling the central axis of the turbine disc to coincide with a rotating shaft of the five-axis machine tool, preliminarily aligning the angular directions of the dovetail-shaped mortises, and then compiling a measuring program of a measuring head of the machine tool; a measuring head is used for measuring the distance deviation between the actual position and the theoretical position of the two side walls of each dovetail-shaped mortise, then the angular direction of the dovetail-shaped mortise is calculated through an algorithm, then the obtained angular direction of the dovetail-shaped mortise is written into a numerical control system, and a basis is provided for subsequen