Rapid mold manufacturing can be used to print wax molds for investment casting, shorten the production cycle and improve the production efficiency. However, in the actual forming process, due to the uneven temperature distribution in different positions of the workpiece, the internal stress will be different, which may result in warping deformation, and then have a significant impact on the forming quality of the workpiece. Moreover, due to the constraints of forming parameters such as 3D printing speed and deposition layers’number, it is difficult to reduce the degree of warping deformation of the workpiece and improve the forming efficiency simultaneously. To solve this problem, this paper establishes a mathematical model for the warping deformation of formed parts, and combines experimental design and mathematical calculation methods to explore the influence mechanism of printing speed on the degree of warping deformation and printing efficiency of casting wax direct writing. Experimental results show that, at a certain printing speed, the warpage value decreases with the increase of the number of deposition layers, while gradually increases with the continuous increase of printing speed; and that the higher the printing speed, the closer the printing time of different samples is to a certain stable value, which means that the impact of printing speed on the forming efficiency decreases with the increase of printing speed. In addition, by assigning weight coefficients respectively to the forming warping deformation and the printing efficiency, a continuous function model for the optimal printing speed of surface contours is established, and the effectiveness of the model is verified. The results show that the continuous function model of optimal printing speed based on the warping deformation of casting wax can simultaneously reduce the warping deformation and improve the printing efficiency. © 2024 South China University of Technology. All rights reserved.