PEEk RP Equipment Development And Experiment Research Based On Simulation

Polyether ether ketone(PEEK)has been widely applied in the field of medical transplant.It is biologically compatible and bioinert;its elastic modulus is very close to that of human bone.The medical PEEK components are difficult to process,because their intricate shape include many hollow structures.To process PEEK models with complex structure,this study uses the fused deposition modeling 3D printer to develop a rapid prototyping equipment for PEEK based on the thermal simulation.Besides,the factors that influence the mechanical properties and precision of PEEK models have been investigated and discussed.Firstly,this work developed the PEEK 3D printer based on thermal simulation.By simulating and comparing the temperature of the feed tube inlet,the structure and the size of the feed tube has been optimized.Based on the optimized feed tube above,the PEEK filament won't soften at the inlet of the feed tube,because the temperature of the feed tube inlet is lower than the glass transition temperature of PEEK.By the thermal simulation and the experiment test,the enclosed stretchable chamber has been developed and optimized.This new chamber can guarantee the uniformity of the chamber temperature,while the chamber temperature is always higher than the glass transition temperature of PEEK,As a result,the 3D printer can print the large size PEEK model smoothly.At the same time,through the warping deformation experiment of the PEEK sample based on the different temperature,we verify the importance of the chamber with high temperature on the dimensional precision of the PEEK sample.Secondly,through the independent factor experiment,following three factors,including the nozzle diameter,the layer thickness and the printing speed have been investigated.And their influences on the bending strength have been studied.By combining experiment data analysis,fluid simulation,SEM test and metallographic microscope,it is concluded that:(1)Using the nozzle with the suitable size,the PEEK model with good bending strength is obtained.(2)When the layer thickness increases,the interlayer combination and the mechanical properties of the PEEK model get worse.(3)When the printing speed increases,it becomes harder for PEEK filament to spin out smoothly from the nozzle.As a result,the texture clearance become bigger,and the mechanical properties of the PEEK become worse.Lastly,through the independent factor experiment,the influence of the nozzle diameter,the layer thickness and the printing speed on the precision of the PEEK model has been researched.Because of the high melting temperature and big linear expansion coefficient of PEEK,the temperature of PEEK filament drops rapidly during the moulding process.As a result,the PEEK shrinks rapidly,and the size of PEEK model become smaller than the design size.To avoid the size error based on the shrinkage,the size of the original model should be corrected proportionally.