Research On Process And Performance Of 3D Printed Components

3D printing(additive manufacturing)is rapidly evolving into a new technology for producing complex components.At present,there is a contradiction between accuracy and efficiency in 3D printing.Components must be processed to ensure accuracy.Research scholars have tried to improve the surface quality by post-processing methods such as sandblasting,machining,acid etching,electropolishing or electrochemical polishing.However,the shortcomings of these post-processing methods,such as poor flexibility and low processing efficiency,limit their engineering applications.Therefore,it is important to explore the subsequent subtractive processing methods of 3D printed components.Nanosecond laser processing shows great advantages in the processing efficiency and processing cost of metal materials,and is expected to become an important technical method for subsequent reduction processing of 3D printed titanium alloys.However,the research on the subsequent laser processing of 3D printed components has just begun at home and abroad,and there are still deep theoretical issues and key technical issues that have not yet been resolved.In order to improve the surface roughness of 3D printed titanium alloy,this paper uses nanosecond laser to polish the surface of 3D printed titanium alloy,and systematically studies the effects of spot overlap ratio,laser power and scanning times on the polishing effect.This article not only realized the improvement of the surface morphology and roughness of 3D printed titanium alloy,but also studied the microstructure and biocompatibility of polished titanium alloy.The main conclusions reached are as follows:(1)The spot overlap rate affects the polishing effect by the energy accumulated on the sample surface.When the spot overlap ratios OP_X and OP_Y are 50%,nanosecond laser polishing can obtain better polishing effect and surface quality,and the roughness is 5.1?m.If the overlap rate is less than 50%,polishing will be incomplete,and if the overlap rate is greater than 50%,the surface will re-melt and solidify to form protrusions,but the roughness will increase.The polishing effect of 3D printed titanium alloy is positively related to the laser power.The best polishing effect can be obtained at a power of 40W,and the roughness is 3.9?m.As the number of repeated laser scans increases,the overall surface roughness of the workpiece decreases.When the number of scans was increased to 10 times,the roughness was 1.3?m.(2)After the 3D printing titanium alloy is polished,?'martensite is formed in the polished area,and its surface microhardness is 35%higher than that of the blank sample surface.The CT results confirmed that laser polishing can reduce the porosity and densify the surface layer.After polishing,the surface layer can reach a density of 99.8%within 0-10?m.The samples treated with LP-2 polishing parameters eliminated external pores and cracks,thereby reducing surface roughness and crack initiation,and improving fatigue resistance.(3)The biological properties of 3D printed titanium alloys were improved after treatment with LP-2 polishing parameters.The contact angle of the sample decreased from102.6°to 68.5°,and the surface was more hydrophilic,providing fine adhesion,proliferation and differentiation for osteogenesis,favorable microenvironment.