Research On Pneumatic Diaphragm-Based Micro Molten Metal Droplet Jetting System And Jetting Forming Characteristics

Additive manufacturing technology,also known as 3D printing technology,is a new manufacturing technology based on digital model,which is made up of solid parts by layering.In the classification of manufacturing metal parts and non-metal parts by 3D printing,the direct forming of metal parts is an important research trend in this field,which is being focused in the developed countries such as Europe and the United States,and also in our country.In this thesis,based on the analysis of various direct metal forming methods,a pneumatic diaphragm-based metal micro droplet jetting system is proposed.This technology classification belongs to micro droplet deposition,which has the advantages of low energy consumption,rich forming material and simple process.Under the balance of various micro droplet jetting technologies,the pneumatic diaphragm-based metal micro droplet jetting technology is selected.It's advantages are low cost,simple structure,stable and controllable jetting,and then the molten metal mirco droplets are accurately deposited on the substrate under the trajectory planning of the moving platform,and then the solid parts are deformed layer by layer.The pneumatic diaphragm-based metal micro droplet jetting system mainly includes two parts of the mechanical platform and the hardware platform.The core of the mechanical platform is the pneumatic diaphragm-based jetting device,and then followed by the platform,the motion platform,the heating element,the pneumatic part,the heating platform of the substrate and so on.The hardware platform is mainly based on the Arduino MCU,which realizes the three-axis control of the motion platform and jetting control,and then connects with the upper computer to provide the man-machine operation interface.On the basis of building an experimental platform for pneumatic diaphragm-based metal micro droplet jetting system,large number of jetting experiments were carried out to study the effects of different jetting parameters such as driving pressure,driving pressure frequency,back pressure of the storage box and working temperature on the jetting characteristics of the micro droplet jetting system.Large scale of jetting experiments are used to select the appropriate control parameters to achieve the precise and steady jetting of the jetting system.On the basis of precise and steady jetting,forming experiments were carried out to study the forming characteristics of pneumatic diaphragm-based metal micro droplet jetting system.It mainly includes the printing of one dimensional line,two-dimensional plane and three-dimensional parts,and studies the influence of the forming parameters,such as the jetting frequency,the substrate temperature and the deposition height,on the forming performance,the surface morphology and the shape precision.On the other hand,one dimensional column sample and three-dimensional rectangle samples are printed,and the tensile tests are carried out to study the influence of the forming parameters on the tensile properties between the micro droplets,the layers and the layers.