Control method for graded preheating of powder bed and additive manufacturing device

Abstract

The invention relates to a control method for graded preheating of a powder bed and an additive manufacturing device. The method comprises the steps that a three-dimensional model of a to-be-printed part is sliced, and a scanning path is set to form scanning path data; according to the section shape of the current layer, the preheating range and preheating energy of the 0-th grade to the n-th grade are set; the energy source performs graded preheating on the powder according to the set preheating range and preheating energy of the current layer; scanning and melting the section according to the scanning path to complete printing of the current layer; and powder laying, preheating and scanning melting are repeated till printing of the whole part is completed. The powder bed is preheated in a graded preheating mode with the section shape of each layer of the printed part as the center, so that large temperature grading of a powder bed preheating area and a surrounding non-preheating area is avoided, the risk of curling, peeling or cracking of the powder bed is reduced, the heating influence of powder of the powder bed outside the section is reduced, the powder utilization rate is increased, and the production cost is reduced. Meanwhile, graded preheating can reduce energy input, and the forming efficiency is improved.

Description

technical field [0001] The embodiments of the present invention relate to the technical field of additive manufacturing, and in particular, to a method for controlling powder bed graded preheating and an additive manufacturing device. Background technique [0002] Additive manufacturing is an advanced manufacturing technology that is driven by data and accumulates materials layer by layer to form solid parts. Compared with traditional technologies, this technology has the characteristics of forming complex shapes and high-performance metal components. Customization and high material utilization rate have been widely used in aerospace, power energy, biomedical and other fields. The powder bed fusion technology spreads a layer of powder on the forming platform in advance through the powder spreading device to form a powder bed. Lay the next layer of powder and repeat the above process to form a three-dimensional solid part. In this process, the quality of the powder bed is o...

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Problems solved by technology

[0006] The existing technology of dividing the mesh to preheat the part area will make the temperature gradient of the part area and the unpreheated powder outside the part area larger, which will easily cause the powder bed around the part to curl and peel, and affect the quality of the lower powder layer and the forming quality of the part; Using concentric circles with different radii to reduce the preheating heat input sequentially from the outside to the inside can improve the temperature uniformity of the powder bed to a certain extent, but the heat input is large when the cross-section of each layer is melted, and the temperature distribution of the powder bed will change with the parts. The cross-section information changes, it does not consider the melting cross-section information of each layer of parts, it is difficult to obtain a uniform temperature field

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