| In the microfluidic control system,the micro nozzle is an important micro device,which is generally used to eject fluid materials to form filaments or micro droplets.The shape is tubular,and the aperture at one end of the outlet is small,generally tens of microns.With the development of science and technology,it has been widely used in various fields,and even involves some more important fields,such as military,medical and health care,and bioengineering.Many of them involve the use of micro nozzles.Therefore,for micro nozzles Research has great prospects.In the field of bioengineering,micro-nozzles are used to install on the print head of a bioprinter to load raw materials such as active cells,extracellular matrix,biological factors,and biological materials to produce a variety of cells,tissues,and organs.In the bioprinter,the micro-nozzle is the main device,which plays a key role.It not only needs to be able to effectively prevent the damage of the bio-ink,but also needs to meet the mechanical forming conditions.Therefore,when selecting the material,it is required not only to have a certain A high degree of chemical stability also requires relatively high mechanical strength to ensure that it will not easily break during the grinding process,but can also be better shaped.In this paper,a capillary glass tube made of borosilicate glass is used to draw a micro-nozzle for bioprinters.The accuracy and quality of the printer is mainly determined by the size of the micro-nozzle.The ejection volume of the bio-ink is mainly controlled by the outlet aperture of the micro-nozzle.At the same time,the length of the neck cone can also affect the entire printing process.Therefore,the size control of the micro-nozzle in the printer is a very important factor that affects the printing accuracy and quality.In summary,this article draws the glass micro-nozzle used in the bio-printer,experimentally studies the processing technology of the micro-nozzle,and continuously innovates and improves the processing technology,which has a certain reference significance for the selection of the micro-nozzle for the bio-printer..The specific work of the thesis is as follows:Analyzing the forming principle of the micro-nozzle,it is concluded that the cylindricity and geometric size of the micro-nozzle are two important factors that affect the printing performance.According to the material performance requirements of the bioprinting micro-nozzle,borosilicate glass is selected as the raw material of the micro-nozzle.The three-dimensional modeling design of the micro-nozzle and micro-stretching device is carried out.Analyze the advantages and disadvantages of various heating methods,and finally choose electromagnetic induction heating as the heating method of the micro stretching device.Through the analysis of the electromagnetic induction heating circuit,the zero-voltage switching circuit is selected as the induction heating circuit,and then the simulation design of the circuit is realized through software,and the appropriate electronic components are selected to produce a circuit board that can generate high-frequency electromagnetic fields.Based on the electromagnetic induction heating circuit board,combined with the designed micro-stretching device model,the micro-nozzle micro-stretching experimental device is built,and the micro-nozzle micro-stretching process flow is introduced in detail.Analyze the theoretical basis of electromagnetic field and temperature field,select appropriate finite element simulation software,and perform finite element simulation analysis on the electromagnetic induction heating model,including the magnetic field analysis of the induction coil,the temperature field analysis of the metal heating tube and the capillary glass The temperature field analysis of the tube,the optimization design analysis of the electromagnetic induction heating model,the process parameters of the micro-tensile experiment are obtained,and the appropriate process parameters are also used as a reference for the research of the micro-tensile experiment.Through the finite element analysis of the electromagnetic induction heating model,the process parameters that affect the stretching of the micro-nozzle are determined.The main research is to study the influence of the size of the metal heating tube and the driving force on the shape and size of the micro-nozzle.The controlled variable method is adopted according to the settings.Different sizes of micro-nozzles are drawn under the experimental conditions,the experimental results are recorded,analyzed and summarized,the scatter diagram is drawn,and the linear equation is obtained by the least squares method.The correlation analysis of each parameter is performed to find out each The degree of influence of process parameters is to study the stretching process of the micro-nozzle.Cooperative analysis and verification of stretching process parameters,experimental research on new methods to improve the precision of micro-stretching.Finally,the experimental results are verified,and the micro-stretching device can accurately draw micro-nozzles of different specifications.The preparation process of glass micro-nozzle is introduced,including the operation methods of broken needle and grinding micro-nozzle.The micro-nozzle grinding experiment platform is built to grind the drawn micro-nozzles,and micro-nozzles with good cylindricity and accurate size can be processed.The experimental research analyzes the grinding process of the micro-nozzle.Finally,it is verified by grinding experiments that a micro-nozzle with good cylindricity can be accurately ground. |
