The Experiment Research Of Selective Laser Melting Of Pure Copper

In this paper,the effects of laser power,scanning speed,hatch space,scanning path and other process parameters on the size accuracy and surface roughness of Selective Laser Melting(SLM)copper forming parts were studied.The main contents and results are as follows:According to the forming principle of SLM,the main sources of error of SLM forming parts are: data processing error,machining error and post-processing error.By establishing the mathematical model,the minimum laser power required to process the pure copper powder in the SLM process is about 355 W.In the range of factor level,the absolute error of size increases with the increase of laser power,and decreases with the increase of scanning speed and hatch space.There is no significant difference in the absolute error between the three scanning paths.The order of the dimensions of the SLM copper powder forming parts is: hatch space > scanning speed> laser power> scanning path,the process parameters of the minimum size absolute error are as follows: laser power is 360 W,scanning speed is 1050mm/s,hatch space is 0.08 mm.The top surface roughness of the forming parts is determined by the theoretical study of the roughness of the upper surface.The surface roughness of the forming parts is determined by the laser power,the scanning speed,the hatch space and the powder bed depth.In the range of factor level,the top surface roughness of the forming element increases with the decrease of laser power,and decreases with the decrease of scanning speed and scanning path.When the scanning path is orthogonal,the top surface roughness is smaller.The order of the surface roughness of the SLM copper powder forming parts is: hatch space> scanning speed> laser power> scanning path,the process parameters of the minimum size absolute error are as follows: laser power is 380 W,scanning speed is 600mm/s,hatch space is 0.05 mm,scanning path is Orthogonal.After expressed the process parameters by volume energy density,I got the relationship between volume energy density and dimensional accuracy as well as that between volume energy density and surface roughness.Combined with the character of the interlaminar morphology,the volume energy density is divided into four zones.The zone Ⅰ is the incomplete melting zone,the zone II is the low energy density region,the zone Ⅲ is the medium energy density region,the zone Ⅳ is high energy density region.The mechanism of volume energy density in each region was analyzed.The SLM pure copper forming parts in the medium energy density region have higher forming quality.This can provide some basis for the selection of process parameters when the pure copper powder is formed by SLM.