Beam customizing module and method and device for reducing laser selective melting porosity defect

Abstract

The invention discloses a method and device for reducing porosity defects in a laser selective melting formed metal part by customizing a beam. Three energy modes: Gauss distribution, hollow distribution and rectangular uniform distribution can be realized as the beam customizing module converts a conventional round Gauss distribution laser beam into a customized beam with an airspace distribution meeting the melted powder demand, controllable temperature gradient and non-continuous time domain distribution. Aiming at a filling area of laser selective melting, solid metal powder is melted quickly by using hollow distributed spots, so that the temperature gradient is reduced. Aiming at an outer contour of laser selective melting, a melting effect of an edge is enhanced by using Gauss distribution, so that the surface roughness is improved. The melted metal is re-melted by using the rectangularly distributed laser, so that the inner porosity of a part is reduced remarkably. The non-stable flow of a melting pool can be reduced, powder at the edge of the melting pool is melted fully, and finally, the porosity defect of the laser selective melting formed metal part is reduced effectively, and the mechanical property is improved obviously.

Description

technical field [0001] The present invention relates to a beam customizing module and a method and device for reducing internal pore defects of laser selective melting metal parts, in particular to a beam customizing module and a method and device for reducing internal pore defects of laser selective melting and forming metal parts by using customized beams , belonging to the field of laser additive manufacturing. Background technique [0002] Selective Laser Melting (SLM) technology is currently one of the main processes used in metal additive manufacturing. Due to its many advantages in forming complex structures, part accuracy, surface quality, etc., it is widely used in aerospace complex parts. , Personalized biomedical devices and other fields have been widely used. [0003] However, there are often porosity defects inside parts manufactured by laser selective melting additive manufacturing technology, which will reduce their mechanical properties, especially fatigue s...

AI Technical Summary

Problems solved by technology

At present, selective laser melting (SLM) generally adopts Gaussian heat source distribution, which will result in higher energy density in the middle area (below the spot) and lower energy density at the edge of the molten pool.

This kind of heat source distribution mode with weak outside and strong inside will bring two typical defects. One is that the energy in the center of the laser spot is often too high, and the temperature in the center of the molten pool is too high, which is easy to cause the "keyhole" phenomenon; the other is the molten pool. The energy at the edge is low, the temperature gradient at the edge of the melt channel is not high enough, and the material is not completely melted, so it will cause "poor fusion", that is, due to the low laser energy density at the edge of the molten pool, some unfused particles will appear. Fusion and adhesion of fused particles inside the molten pool, porosity defects also occur

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