Study On Laser 3D Printing Of Silicon Carbide

With the development of science and technology,new materials,information technology,new energy,and bioengineering have become the four pillar industries for the development of productive forces in today’s society.Advanced ceramic materials are an important part of the new materials field and have received important attention in the industrial field.As an extremely important engineering ceramic material,Si C ceramics have developed rapidly in the field of materials due to their excellent physical and chemical properties,and are widely used in many industrial fields.Due to t he high strength and high hardness of such ceramic materials,it also brings many difficulties to the forming and processing of parts.In the manufacturing industry,3D printing technology provides a new way to overcome the shortcomings of traditional technology.Based on the importance of silicon carbide ceramics in the industrial and electronic fields,this paper systematically studies the selective laser sintering process of silicon carbide ceramics and the stereolithography process of silicon carbide ceramics.This paper independently develops the powder consumables that meet the requirements of the printing process,overcomes the problem of integrated silicon carbide in complex structure,and further explores the optimal laser forming process parameters,forming a batch of silicon carbide parts blanks with certain precision and strength.Finally,the post-processing process of 3D printed state silicon carbide part blanks is studied and discussed.The selective laser sintering of polypropylene silicon carbide composite powder is prepared by coating method.In order to strengthen the adhesion between the polymer and the silicon carbide ceramic powder,the silicon carbide is modified.And the modified powder was prepared by chemical modification using 10% silane coupling agent KH-570.Polypropylene SiC composite powder are formed under selective laser sintering equipment of CO₂ laser.The laser energy density is 0.010-0.021 J/mm².The optimal process parameters are preheating temperature of 115 ℃,laser power of 15 W,scanning speed of 3200 mm/s,and the scanning spacing is 0.3 mm.The polypropylene composite powder body has t he highest density and reaches 30%,and the polypropylene modified silicon carbide composite powder body has a density of up to 32%.In order to realize the stereolithography of high refractive index silicon carbide powder,the silicon carbide powder is subjected to high temperature oxidation modification,and the oxidation temperature is 1400 ℃,which successfully solved the problem of silicon carbide light curing forming.Studies have shown that when adding 1 wt% PVP and ball milling for 8 h,the homogenization of ceramic slurry has achieved the best effect.The parameters of the stereolithography process were selected and optimized.The heating temperature was 35-40 ℃,the thickness of the single layer was 25 μm,the curing time was 120 s,and the printing time of the components was not more than 12 h.The addition of the light-curing member support depends on the orientation of the printing member on the platform,and the density of the support and the contact point size should be appropriate.The degreasing and sintering mechanism and process of selective laser sintered silicon carbide green body were studied.The degreasing curve was determined and the pre-sintering temperature was determined at 1000 ℃.The degreasing shrinkage behavior of Si C ceramic parts was studied.The linear shrinkage of the sample in the X direction was 3.25%,the linear shrinkage in the Y direction was 3.10%,and the linear shrinkage in the Z direction was 2.53%.The degreasing process of the stereolithography green body showed that the polymer additive completely decomposed at a temperature of 272-589 ℃,and the organic polymer was completely decomposed after 600 ℃.