| Precision manufacturing technology reflects the level of a country 's high-end manufacturing,and is of vital importance to the quality of life of the people and the development and construction of the country.Since the 21 st century,China's manufacturing industry has developed rapidly.In many fields,the structure of mechanical parts has become more and more complicated,and the mechanical performance requirements have become higher and higher.Special processing technology and rapid prototyping technology have emerged.With the rapid development of modern medical industry,medical titanium alloy implants have extremely wide application requirements in biomedical fields such as oral cavity,neurosurgery,cardiovascular,thoracic,otolaryngology,and orthopedics.Titanium alloy electron beam powder melting technology is a very promising digital rapid prototyping processing technology,but so far there are still some problems in the research and development of related equipment in China: the lifting table is difficult to achieve closed-loop control,and the motion accuracy is not high;The powder spreading effect needs to be improved;the forming size is small and not adjustable.This research topic combines the task requirements of the National Natural Science Foundation of China's major scientific research equipment development project,for the development of medical titanium alloy implants electron beam powder melting equipment,the structural design and performance research of the creation lifting table and powder spreading device is the project The follow-up research laid the foundation.The main research contents of this article:(1)Study the influence of the powder spreading process on the density,shrinkage,warpage and surface accuracy of the formed parts through theoretical calculations,and explore the effect of particle size and mechanical structure accuracy on the powder spreading effect.Determine the powder spreading method and the rotation method of the pressing roller,and on the basis of theory,calculate the optimal value of the technical parameters of the powder falling hopper and the powder spreading roller.(2)According to the results of theoretical calculations,combined with the existing technology in the domestic market,the solution of the entire project is determined: the lifting table adopts inchworm-type lifting movement,displacement measurement feedback through the grating displacement sensor,and the lifting drive and error compensation using the wedge block,To achieve a closed loop control system of motion + measurement + compensation;the powder spreading device uses a combined powder spreading method that combines powder pressing and falling powder to improve the quality of powder spreading,and the built-in width adjustment mechanism realizes the adjustment of the powder spreading area.Using catia software to design the three-dimensional model of the equipment,clarify the overall layout of the device and the mechanical structure design,technical parameters,working principles and innovations of each module.(3)Use the ANSYS Workbench finite element analysis module to perform static analysis and modal analysis on the main components,and perform structural optimization and material selection according to the simulation results.Establish mathematical models of lifting table modules and powder spreading modules,determine the process parameters of part of the processing process,and design the electrical system of the main modules.(4)Set up the test bed sample machine,mainly including the lifting table device and the powder spreading device.Carry out relevant verification tests and performance tests of key modules using test bed prototypes,including load verification tests,powder fall verification tests,motion accuracy measurement tests,and powder spreading effect demonstration tests.According to the test results,analyze the cause of the error and propose an improvement plan,master the test method,and pave the way for the development and test of the second generation prototype. |
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