Abstract—In recent years, 3D printing technology has focused on the development of new materials and shortened manufacturing time. In the light curing process, the printing time of the surface projection molding technology called digital light processing (DLP) can be shorter than the point projection molding technology, and has better development. With the open-loop control system of bottom-up type of DLP machine, the user should set the rise time of printing platform in each layer according to the experience before the printing starts. Therefore, the user experience will determine the printing efficiency. This study proposes to use case-based reasoning (CBR) method to improve printing efficiency. The printing parameters of machine, the geometry of printing object and the separation time are all recorded in a case format. The printing parameters that affect the separation time become the characteristics of the index system. The most similar case is obtained from the case base through the similarity calculation, and rising time of the platform is obtained through the case correction rule. Finally, the effect of the inference system is confirmed by a case study.