| Biological manufacturing is the frontier in the field of medicine. With theemerging of the high-energy trauma and the trend of the aging of the population, thedevelopment of bionic artificial bone repair material with good structure andbiological compatibility is particularly important. Special plastics poly ether etherketone (PEEK) has excellent mechanical property, wear resistance and chemicalstability, it is an ideal replacement material for artificial bone. Among all themanufacturing methods of artificial bone,3D printing technology shows greatadvantage in the manufacturing of artificial bone with its high precision, high strengthand individuation. Fused deposition modeling is a relatively mature technology in3Dprinting. For the maintenance and post-processing of the process is simple and thecost of operation is low, it is suitable for the individual processing of artificial bone.In this paper, the author simulates the actual3D printing process on the basis of fluidmechanics theory and experiments the mechanics property of printing partsmanufactured by self-developed3D printing machine. This paper breaks through thelimits of materials for3D printing and enriches the methods of manufacturing forartificial bone. It has great practical value in3D printing field.This research gives the basic equations of fluid motion using Euler method.According to the characteristics of the polymer melting flow process, some conditionis simplified during the actual process and the continuity equation, motion equationand energy equation are given for poly ether ether ketone (PEEK). Power-Law modelconstitutive equation is established based on the characteristics of PEEK. Then, thecontinuity equation, motion equation and energy equation is discrete through Galerkinweighted residual method. The boundary conditions is substituted into the equationfor numerical solution. The model of the melting fluid is set up by CATIA, thenimported into FLUENT to CFD fluid simulation analysis. With finite element method,the velocity, pressure and temperature distribution is obtained. The influence of nozzle temperature T and printing speed V on the distribution is discussed in the end. Thesimulation results show temperature, velocity and pressure distribution spread at thecenter of the geometry. The pressure and velocity changes obviously close to thenozzle exit. The change of nozzle temperature has little influence on the distributionof temperature and pressure, but it will affect the peak value of the velocity. Underdifferent printing speed, the pressure at the exit increases and the of isobar scopeexpand gradually near the export with the printing speed going up. At he same time,the increasing of the velocity will reduce the heating time of melt in the flow channel,which will causes the decreasing of the fluid temperature.A PEEK3D printing system is developed based on Fused Deposition Modelingfor special material of poly ether ether ketone (PEEK). Tensile and bendingmechanical property is experimented for PEEK samples. The mechanical property ofPEEK samples and ABS-P430samples printed by Stratasys Uprint SE is alsocompared. The mechanical properties of tensile, compression, bending is obtained andthe stress-strain curve is acquired from it. SEM analysis is carried out on the crosssection of tensile samples for both PEEK and ABS-P430and the microstructure of thetensile fracture is observed. The experiment results show that the raster angle and thelayer thickness are important parameters in the process of PEKK3D printing and theyhave a great influence on the tensile and bending property of the samples; When rasterangle is0°and layer thickness is300μm, the mechanical property reach the tide; Themechanical property drops after3D printing for both PEEK and ABS-P430. Themechanical property (tensile, compression and bending) of PEEK samples is higherthan that of ABS samples manufactured by commercial3D printers. |
PDF Full Text Request