CFD Analysis Of Fused Deposition Modelling Nozzles And Optimal Design Of Mixing Nozzles

With the progress of the times, the demand for personalized customized products become increasingly strong. For the abiilty of transforming the product of thinking into the model with a certain function or the parts that can be used directly, RPM(Rapid Prototyping Manufacturing) was quickly accepted by society and become more and more popular since it was producted. And FDM(Fused Deposition Modeling) is more mature and widely used in several kinds technologies of RPM. In the technology, melt filament stacked up in accordance with the layers of 3D model after slice processing. The raw material is thermoplastic material in the process, in the research, biodegradable plastic PLA(Polylactide Acid) is used as raw materials, and the analysis of nozzle is based on the CFD(Computational Fluid Dynamics) software Star CCM+.First of all, the simulation based on 3D models of several common nozzles in the market should be analysised, for the design of the mixing nozzle, the performance of nozzles is analysised based on the structure characteristics and the structural parameters. And then the influence of the internal channel cone angle, the length of outlet and the feed velocity on the flow resistance should be analysised. The results show that the length of outlet is an important parameter of nozzle which value is positively correlated with the flow resistance.Then we should design the double color mixing nozzle, after designing of Y type double color mixing nozzle, the mixing effect can be used to optimize the structure of nozzle, repeat this process until the design of filtering type double color mixing nozzle with better mixing effect. Y type and filtering type mixing nozzle are used for comparative test of simulation, and a matching connector of each nozzle is must. The rusults show that it is feasible to design a mixing nozzle with simulation method, and the filtering type mixing nozzle is better than Y type mixing nozzle. Then, the effect of different structure, total feed velocity and relative feed velocity on the mixing effect of the double color mixing nozzle is verified by experiments, the rusults is correct.Based on the performance analysis of single color nozzle and the design experience of the double color mixing nozzle, the design work of the triple color mixing nozzle is carried out, the mixing effect of different relative feed velocity should analysised by simulation. The rusult show that, the mixing effect of triple color mixing nozzle is preferable. And the experimental results are consistent with the simulation results, the mixing effect of the triple mixing nozzle is better than double mixing nozzle, and three kinds of colors can be mixed into a variety of colors, the raw material feeding speed change sensitivity is high.Because of the research on mixing nozzles is very little, the research on the mixing nozzles is of great significance to enrich the design theory of 3D printer nozzles. The research conclusion has great reference value.