US 12,422,406 B2
Method and system for detecting structural defect in additive manufacturing
Chao Zhang, Nanjing (CN); Zhaomin Wang, Nanjing (CN); Hongli Ji, Nanjing (CN); Jinhao Qiu, Nanjing (CN); Chongcong Tao, Nanjing (CN); and Jun Wang, Nanjing (CN)
Assigned to NANJING UNIVERSITY OF AERONAUTICS AND ASTRONAUTICS, Nanjing (CN)
Filed by NANJING UNIVERSITY OF AERONAUTICS AND ASTRONAUTICS, Nanjing (CN)
Filed on Oct. 28, 2022, as Appl. No. 18/050,656.
Claims priority of application No. 202210727484.4 (CN), filed on Jun. 24, 2022.
Prior Publication US 2023/0417707 A1, Dec. 28, 2023
Int. Cl. G01N 29/06 (2006.01); B33Y 40/00 (2020.01); B33Y 50/00 (2015.01); G01N 29/22 (2006.01); G01N 29/46 (2006.01)
CPC G01N 29/06 (2013.01) [B33Y 40/00 (2014.12); B33Y 50/00 (2014.12); G01N 29/225 (2013.01); G01N 29/46 (2013.01); G01N 2291/0289 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A method for detecting a structural defect in additive manufacturing, comprising:
layering a three-dimensional model of an additive manufacturing test piece to obtain a two-dimensional contour of an interface of each layer, and generating a machining path;
arranging a non-contact sensor at a fixed measuring point of the additive manufacturing test piece, and acquiring an ultrasonic signal at each machining point when a pulse laser conducts machining point by point along the machining path;
forming a visual ultrasonic field based on all the ultrasonic signals and determining ultrasonic field data, wherein the forming the visual ultrasonic field based on all the ultrasonic signals, and determining the ultrasonic field data comprises:
allowing the visual ultrasonic field to be equivalent to exciting an ultrasonic wave at the fixed measuring point, and sensing the ultrasonic signal at each machining point of the machining path; and
placing the ultrasonic signals measured along the machining path into a two-dimensional array in chronological order to determine the ultrasonic field data;
determining, based on the ultrasonic field data, a curve of a peak of an incident wave changing with the machining path;
determining whether a machining defect exists at each machining point based on the curve of the peak of the incident wave changing with the machining path; and
performing one of the following:
if the machining defect exists at each machining point, removing the additive manufacturing test piece, or
if the machining defect does not exist at each machining point, determining that the additive manufacturing test piece has an intact structure, and continuing additive manufacturing of a next layer.