During the complex parts of 3D printing processing, many processing defects, such as cracks, burr, and collapse, are beginning to form in the scanning around the corner. To reduce the scanning defects of different angle corners, the thermo–mechanical coupling field of different parts are simulated and the thermal and stress cloud pictures are analyzed. The relationshape about the machine tool's acceleration, the size of angle, the temperature of angle, temperature gradient and thermal stress are gained. The simulation results show that the thermal stress of corners not only rely on the machine tool's acceleration, but also contact closely with the angle of corners with both sides. The temperature results of simulation and the forming quality of the different angle of corners are verified by the experiment.