Research On Some Key Technologies Of A Fused Deposition Modeling Feeding Filament System

As a mature Rapid Prototyping technology, Fused Deposition Modeling (FDM) technology has been widely used in many fields, because of its technologic advantages, such as simple structure, small volume, low cost, and no pollution. However, due to the poor stability of its feeding filament system, some problems (e.g., nozzle blockage, leakage, and ooze) often occur during the runing of FDM equipment. All of these will directly influence the result of the forming process, and has a great effect on the quality of the forming models. Therefore, this paper mainly focuses on some key technologies of the FDM feeding filament system.Firstly, after analysing the overall functional requirements of the FDM feeding filament system, this paper formulates the overall system scheme considering the mechanical structure, the temperature control system, and the optimization of FDM process parameters.Secondly, this paper proposes solutions to address the defects of the mechanical structure of the current FDM feeding filament system:(1)This paper puts forward an adaptive feeding device with a spring to avoid the disadvantages of the current feeding device. (2) This paper designs and optimizes the mechanical structure of the heating block and the nozzle according to the analysis of the resistance of the molten filament in the flowing channel. (3) This paper develops a new kind of feeding throat that is built in a teflon tube in order to avoid the jam of the nozzle. (4) This paper also presents the relationship between the feeding length of the feeding filament system and the steps of the stepping motor in order to accurately control the system.Thirdly, this paper develops a fuzzy adaptive PID control method to improve the temperature control of the current feeding filament system that uses the conventional PID control method. The results from practical applications show that the new method based on the fuzzy adaptive PID control method has smaller overshoot and can reach the stable point faster.Finally, after analyzing the influence of some key FDM process parameters on the surface quality of forming parts, this paper puts forward the optimal solution for these parameters. Through the design of standard specimen, the orthogonal test is carried out to analyze the relationship between these parameters and the surface quality. As a result, this paper summarizes the optimization results of these FDM process parameters.The FDM feeding filament system in this paper effectively solves problems during processing, e.g., nozzle blockage, leakage and ooze. This system ensures the stablilty of the entire forming process, and can obviously improve the forming quality of molded parts.