Effects of processing parameters on the temperature field of selective laser melting metal powder

Abstract

Based on temperature-dependent thermophysical parameters and nonlinear phase transformation from powder to liquid, a three-dimensional transient thermal finite model of selective laser melting process is developed. Commercial ANSYS software is used to simulate the distribution of the temperature field in selective laser melting. The simulation results show that a lower scan speed, higher laser power, and a lower scan interval enable much higher maximum temperature in the powder bed and wider scan track width. The scan modes also have great influence on the temperature field. Temperature in the powder bed experiences fluctuant variation with transverse scan mode in contrast with moderate variation with lengthwise scan mode. The simulated results are compared with the experimental results and good agreement is found in scan track width.

Simulation of metallic powder bed additive manufacturing processes with the finite element method: A critical review

“…Whereas width measurements were found to be in good agreement with the simulation results, it is reported that the simulated track height cannot capture height deviations occurring as the layer undergoes thermal shrinkage and densification. Good agreement between simulation and experimental results was also reported by Li et al, 32 when studying the effect of scanning speed into track width. The melt pool dimensions and the presence of ''balling'' were experimentally recorded by Childs et al 72 using photography and video recording at a rate of 25 frames per second.…”

“…39 The increase of the beam power causes the melt pool width and length to increase. 32,42,49,50 The depth of the melt pool also increases with beam power. 43 Generally, a larger melt pool is produced when increasing the power of the heat source.…”

Balling behavior of stainless steel and nickel powder during selective laser melting process

“…In the meanwhile, the scan tracks became discontinuous and broke up into balling. It was because the laser energy was low under high scan speed [18], leading to worsened wetting ability and accordingly balling initiation. In addition, under high scan speed and low laser energy, the asformed molten pool dimension was too small that the contact area between molten pool and substrate was considerably limited, leading to unfavorable wetting, flowing, spreading characteristics, and corresponding balling phenomenon.…”

A review on measurement science needs for real-time control of additive manufacturing metal powder bed fusion processes

“…Others [138], [140], [144] also studied pre-heating and post-heating of a surface point before and after the laser scan had passed on one layer (rather than subsequent layers). Under certain conditions, locations on previously scanned tracks were re-melted.…”