Method of feedback controlling 3D printing process in real-time and 3D printing system for the same

A 3D printing system capable of real-time feedback control of a 3D printing process, comprising:

• a laser source configured to form a molten pool in a 3D printing object by irradiating a laser beam to melt a base material supplied to the 3D printing object;
• a base material supply source configured to supply the base material onto the 3D printing object;
• a thermal imaging camera configured to acquire a thermal image of the molten pool formed on the 3D printing object;
• a laser ultrasonic device configured to receive a laser ultrasound wave reflected from the 3D printing object;
• and
• a control unit configured to perform the functions of:
• collecting big data, generated through 3D printing experiments, related to process variables of 3D printing, measurement signals, and 3D printing quality of the 3D printing object;
• building an artificial neural network model by performing machine-learning based on the collected big data;
• evaluating whether or not a 3D printing quality of the 3D printing object is abnormal in real time based on an actual measurement signal of the 3D printing object and the artificial neural network model;
• and feedback controlling printing quality of the 3D printing object in real time based on the evaluation result of whether or not the 3D printing quality of the 3D printing object is abnormal,
• wherein the function of collecting the big data includes the sub-functions of:
• collecting the process variables of 3D printing;
• measuring a thermal image and an ultrasonic signal for the 3D printing object;
• estimating 3D printing quality by analyzing the collected process variables and the measured thermal image and the ultrasonic signal;
• and collecting big data related to the estimated 3D printing quality in real time during the 3D printing process, and
• wherein the thermal imaging camera and the laser ultrasonic device are disposed coaxially with the laser source for 3D printing.