Abstract
A 3D printing device includes a printing unit and a sensing unit. The printing unit has a moving base and a laser emitter. The laser emitter is fixed on the moving base for emitting a laser beam onto a workpiece to be processed. The laser beam forms a processing point on the surface of the workpiece to be processed. The sensing unit has a movable ring and a temperature sensor. The movable ring is rotatably in socket joint with the laser emitter, and the temperature sensor is mounted on the movable ring so that the temperature sensor can rotate around the emission point of the laser beam due to the actuation of the movable ring. As such, the temperature sensor is held in front of the processing path of the laser beam, so as to sense in advance the temperature change of the surface of the workpiece to be processed in front of the processing point, and then adjust in real time the process parameters of the laser emitter according to the sensing result.