The Design And Property Of Conformal Cooling Channels Fabricated By Selective Laser Melting

The injection mold cooling system affects the quality and production efficiency of the molded products,the molded products are prone to defects such as warpage and uneven shrinkage because the conventional cooling system is difficult to achieve uniform cooling of the mold.The conformal cooling channel can achieve uniform cooling because it changes with the product shape,which can significantly improve the quality of the product and reduce the cooling time.The conformal cooling channel has a strong applicability,but the traditional processing method is not suitable for processing with the conformal cooling channel.Selective laser melting as a kind of additive manufacturing,as the prepared metal parts have high density,high strength and low surface roughness,it can reduce the investment cost and save the manufacturing time,for injection mold manufacturing bring revolutionary development.In this paper,the 18Ni300 powder was used as the experimental material,and the process and properties of 18Ni300 were studied by using EOS M290 laser melting equipment,the main research contents and results are as follows:In the forming process,the L₉?3⁴?orthogonal experiments were carried out.The results show that the optim?m parameters of SLM are:laser power 285W,scanning speed 960mm/s,scanning distance 0.11mm,powder thickness 40?m,at this time the input energy density is67.47J/mm³,and it can get the density of up to 99.99%.In the aspect of molding performance,the L₉?3⁴?orthogonal experiments were carried out,and the microstructure,phase,mechanical and properties of 18Ni300 maraging steel were studied.The results show that SLM parts are mainly composed of martensite and a small amount of austenite,and the hardness,tensile strength and elongation of18Ni300 maraging steel manufactured by SLM were 34.8HRC,1165MPa,12.4%,and the fracture mechanism is transgranular ductile fracture?After the solution heat treatment,maraging steel phases consist of a single??bcc?phase,and the hardness,tensile strength and elongation of 18Ni300 maraging steel were 28.4HRC,1025MPa,14.4%,and the fracture mechanism is transgranular ductile fracture.When the maraging steel was aged at 400°C,480°C,and 560°C for different time,the hardness and strength reached the peak after 32h,16h,and 1h respectively,and all the fracture mechanism was ductile ductile fracture.???phase transition occurs during the solution?aged heat treatment?In the aspect of forming ability of SLM 18Ni300 maraging steel,The roughness of the upper surface and the lower surface decreases with the increase of the manufactured angle,and the roughness of the upper surface is smaller than that of the lower surface.Different SLM forming angles have no effect on tensile strength and bending strength,but they have a significant impact on impact toughness and elongation,and impact toughness and elongation are lowest at 60°and 70°respectively.We drew typical geometric features of mechanism,such as thin-walled part,hole,angle,high aspect ratio part.The quality of SLM manufactured parts were evaluated,the evaluation criteria includes the maxim?m/minim?m size and dimensional error.At last,design rules of geometric features based on SLM direct manufacturing were extracted.In the aspect of simulation of conformal cooling channel,base on the theory of traditional injection molding ducted cooling and heat transfer systems,a simplified model for conformal cooling channel was established.As the goal of uniform cooling,the L₉?3⁴?orthogonal experiments were carried out and the factors of heat transfer were studied with CAE simulation software,one of the most important factors is the distance between cooling channels?...