Numerical simulation method for predicting selective laser melting single-melt-channel forming defect

Abstract

The invention provides a numerical simulation method for predicting a selective laser melting single-melt-channel forming defect. The method comprises the steps that S1, establishing a powder bed particle model through EDEM software; s2, selecting a powder bed particle material, and gridding the powder bed particle model; s3, establishing a multi-physical-field model for simulating required heat transfer and molten pool driving force; and S4, selecting laser power and scanning speed as objects to respectively simulate multiple groups of different process parameters. The invention provides a numerical simulation method for predicting the selective laser melting single-melt-channel forming defect, the powder bed model is established through a discrete element method, a heat transfer and molten pool driving force multi-physical-field model is constructed, and numerical simulation is carried out on single-melt-channel forming to obtain a final morphology result; and the formed single meltchannel is evaluated, the defect phenomenon is analyzed, and reference is provided for optimization of technological parameters.

Description

technical field [0001] The invention belongs to the field of selective laser melting, and in particular relates to a numerical simulation method for predicting forming defects of a single melting channel in selective laser melting. Background technique [0002] Laser selective melting is the use of laser beams to melt the metal powder pre-laid on the two-dimensional cross-section according to the predetermined path, melting and solidifying layer by layer from bottom to top to form solid parts; in SLM molding, the most basic molding unit of single melting channel , the molding defects of single melt channel directly affect the final product quality, and the construction of high-quality single melt channel is an indispensable condition for the successful printing of metal parts; numerical simulation can intuitively and quickly predict the defect phenomenon in single melt channel forming , to provide a reference for the selection of process parameters; however, most of the exis...

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Problems solved by technology

[0002] Laser selective melting is the use of laser beams to melt the metal powder pre-laid on the two-dimensional cross-section according to the predetermined path, melting and solidifying layer by layer from bottom to top to form solid parts; in SLM molding, the most basic molding unit of single melting channel , the molding defects of single melt channel directly affect the final product quality, and the construction of high-quality single melt channel is an indispensable condition for the successful printing of metal parts; numerical simulation can intuitively and quickly predict the defect phenomenon in single melt channel forming , to provide a reference for the selection of process parameters; however, most of the existing SLM simulations simplify the metal powder into a continuous geometry with certain characteristics, which cannot accurately describe the characteristics of the powder particles. Only the heat transfer mechanism is considered in the simulation, and the driving force of the molten pool is not considered; at the same time Heat transfer considerations are not comprehensive, evaporative heat dissipation, convection heat dissipation are not considered, and the flow deformation of the molten pool under the laser is not considered, resulting in low simulation accuracy and inability to accurately predict defects generated by the molten channel

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