Design & Dynamic Structural Optimization On Rapid Prototyping Desktop System MEM200-D

As one of the two major developing trends, Rapid Prototyping Desktop System has been the research focus of rapid prototyping industry nowadays. Desktop System means that it is fit for office and has low cost, compact volume, light weight and also high speed, low noise in molding process. After several typical foreign desktop systems had been studied, MEM (Melted Extrusion Manufacturing) process was chosen as the molding process of the first Rapid Prototyping Desktop System in China, MEM200-D, which combined our technical advantages and design experiences. By using the mechatronic design and modularization method, the system scheme design, layout design and part/assembly design have been achieved. After plenty of practices, it is discovered that the main factor that lowers the part precision and accelerates the aging of parts is the vibration caused by the inertia force of extrusion head in high speed scanning movement. Rapid Prototyping Desktop System needs not only to achieve enough part precision in high speed scanning but also to reduce the vibration and noise as most as possible. Therefore, further research on vibration of MEM systems must be carried on.After thoroughly studying the MEM process, the frequency range of inertia force, which is caused by the scanning movement of extrusion head, has been found. Then, the Experimental Modal Analysis method was applied to the study of vibration performance of current MEM system. After comparing the inherent frequency with the frequency of inertia force, the basic source of violent vibration of MEM systems was found and corresponding criterion of anti-vibration structure design was formulated.The dynamic structure design of MEM200-D framework was carried on with FEM based dynamic computation, in which the design criterion of anti-vibration was used. Strength verification was also applied to the framework. The result of Experimental Modal Analysis on the model machine shows that the design satisfies the criterion of anti-vibration structure design. It also validates the reliability of thefinite element model of MEM200-D. Further research of general optimization and local optimization was carried on the model. Thus the optimum design of MEM200-D structure, that not only satisfies the criterion of anti-vibration design but also reduces the weight, was resulted.