Research And Development Of Active Mixing Printhead For Multi-material And Multi-scale 3D Printing

With the rapid development and wide application of 3D printing technology,3D printing of single material has been difficult to meet the needs of the performance of the product.People put forward higher requirements for 3D printing: can realize composite materials,functionally graded materials,the variable density of heterogeneous materials in multi materials and multi scale printing;the different material properties are integrated on the same printed parts,the material,structure,functional components of the integrated design and manufacturing.Multi material multi scale 3D printing brings more new possibilities for wearable devices,flexible robots and electronic products Multi material and multi scale 3D printing represents the leading edge and the future development of the technology of increasing material manufacturing,which has great potential and broad application prospects.Aiming at the problems existing in the current multi material 3D printing,this paper presents a multi-scale and multi-material 3D printing process based on single printhead.A novel active mixing printhead which is considered as one of the core functional elements is proposed and is investigated systematically by combining the theoretical analysis,numerical simulation and experimental verification.In this paper,the specific research work is as follows:This paper designs the core components of the multi material 3D printing—Active mixing head,and introduces the function of each part in detail.The mixing process and flow field structure of the internal fluid of the active mixing nozzle are analyzed.According to the control equations of fluid mechanics,turbulent fluid mechanics equations and concentration transport equation,introduces the mixing mechanism of active hybrid nozzle,expounds the influence law of impeller diameter,impeller speed,fluid viscosity,volume force and other factors on the mixing performance.Based on the theoretical analysis,COMSOL simulation software is used to simulate the mixing process.By changing the diameter of the impeller,impeller speed and viscosity of the fluid,the fluid mixing state observation,reveals the impeller diameter,impeller speed,fluid viscosity to influence the mixing performance of multiple materials,to verify the correctness of theoretical analysis.The overall structure design of the multi material 3D printing experiment table is carried out.The process flow of multi material 3D printing is introduced in detail.Finally,a multi material 3D printing experimental platform with active mixing head is built.Finally,making use of multi material 3D printing experimental makes variable stiffness model and functional gradient structure model and micro scale models of three typical experimental cases,verify the correctness of the research results for active hybrid simulation analysis and Simulation of the nozzle theory.At the same time,it is proved that the multi material 3D printer is practical and feasible in the manufacture of multi material and multi scale parts.