Method and system for detecting structural defect in additive manufacturing

A system for detecting a structural defect in additive manufacturing, comprising:

• a machining path generation module, configured to layer a three-dimensional model of an additive manufacturing test piece to obtain a two-dimensional contour of an interface of each layer, and generate a machining path;
• an ultrasonic signal acquisition module, configured to arrange a non-contact sensor at a fixed measuring point of the additive manufacturing test piece, and acquire an ultrasonic signal at each machining point when a pulse laser conducts machining point by point along the machining path;
• an ultrasonic field data determining module, configured to form a visual ultrasonic field based on all the ultrasonic signals, and determine ultrasonic field data;
• a module, configured to determine, based on the ultrasonic field data, a curve of a peak of an incident wave changing with the machining path;
• and
• a machining defect determining module, configured to determine whether a machining defect exists at the machining points based on the curve of the peak of the incident wave changing with the machining path;
• and if a machining defect exists at the machining points, remove the additive manufacturing test piece;
• or if no machining defect exists at the machining points, determine that the additive manufacturing test piece has an intact structure, and continue additive manufacturing of a next layer.