Additive manufacturing stress deformation control method for large-projection-area inclined plane structure

Abstract

The invention relates to an additive manufacturing stress deformation control method for a large-projection-area inclined plane structure, and belongs to the technical field of selective laser melting forming. Designing a grid unit and a BCCZ configuration dot matrix for supporting the inclined plane structure; laying to manufacture a substrate; performing shot blasting treatment on the upper surface of the substrate; a line-by-line scanning mode is adopted on the upper surface of the substrate, and the grid units, the BCCZ configuration dot matrix and the inclined plane structure are integrally formed; the grid units, the BCCZ configuration dot matrix and the inclined plane structure are detached from the substrate; the grid units and the BCCZ configuration dot matrix are dismantled, and inclined plane structure forming is completed; according to the invention, the stress control of the component in the vertical direction and the horizontal direction is realized, and the high-precision forming of such parts is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of laser selective melting forming, and relates to a stress deformation control method for additive manufacturing of a large-projection-area inclined surface structure. Background Art

[0002] Selective laser melting is an additive manufacturing technology based on powder bed laying, with the characteristics of pre-setting powder laying, galvanometer scanning, small spot diameter, high power density, fast scanning speed, and high forming accuracy, which is suitable for the overall manufacturing of complex precision components. However, due to the technical characteristics of rapid heating and cooling of the micro-molten pool in selective laser melting, large internal stress will be generated during part forming. Excessive internal stress can easily cause part deformation, and in severe cases, it can cause part cracking. Summary of the invention

[0003] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art, to propose a stress deformation control method for additive manufacturing of a large projected area inclined surface structure, to achieve stress control in the vertical and horizontal directions of the component, and to achieve high-precision forming of such parts.

[0004] The solution of the present invention is:

[0005] A stress deformation control method for additive manufacturing of a large-projection-area inclined surface structure, comprising:

[0006] Design grid cells and BCCZ configuration lattices for supporting inclined surface structures;

[0007] Lay up layers to make substrate;

[0008] Shot peening is performed on the upper surface of the substrate;

[0009] The upper surface of the substrate is scanned line by line to form a grid unit, a BCCZ configuration lattice and an inclined surface structure in an integrated manner;

[0010] The grid unit, the BCCZ configuration lattice and the inclined surface structure are removed from the substrate; the grid unit and the BCCZ configuration lattice are removed to complete the formation of the inclined surface structure.

[0011] In the above-mentioned method for controlling stress and deformation in additive manufacturing of a large-projection-area inclined surface structure, the grid unit and the BCCZ configuration lattice are located at the bottom of the inclined surface structure and within the projection area of ​​the inclined surface structure; when forming the inclined surface structure, support for the inclined surface structure is achieved by realizing the grid unit and the BCCZ configuration lattice.

[0012] In the above-mentioned stress deformation control method for additive manufacturing of a large projected area inclined surface structure, when the grid units and the BCCZ configuration lattice support the inclined surface structure; the grid units are evenly distributed to form a grid matrix; gaps are left between adjacent grid units; and the BCCZ configuration lattice is embedded in the gaps in the grid matrix to form a support body.

[0013] In the above-mentioned method for controlling stress and deformation in additive manufacturing of a large-projection-area inclined surface structure, the grid unit is a field-shaped structure; the side length of the grid unit is 1.6-3.2 mm; and the gap between two adjacent grid units is 0.8-1.6 mm.

[0014] In the above-mentioned method for controlling stress and deformation in additive manufacturing of a large-projection-area inclined surface structure, the BCCZ configuration lattice includes 1 central rod and 4 diagonal rods;

[0015] Among them, the central rod is placed axially vertically; the four diagonal rods are arranged to cross each other, and the intersection point is located in the middle of each diagonal rod; the central rod passes through the intersection point of the four diagonal rods, and the intersection point is located in the middle of the central rod.

[0016] In the above-mentioned method for controlling stress and deformation in additive manufacturing of a large-projection-area inclined surface structure, the tops of the four diagonal rods are flush with the top of the central rod; and the bottoms of the four diagonal rods are flush with the bottom of the central rod.

[0017] In the above-mentioned method for controlling stress and deformation in additive manufacturing of a large-projection-area inclined surface structure, the vertices of the four diagonal rods serve as the corner points of a square, and the lines connecting the four vertices form a square; the bottom points of the four diagonal rods serve as the corner points of the square, and the lines connecting the four bottom points form a square; the overall outer envelope of the BCCZ configuration lattice is a rectangular structure, and the side length of the rectangular structure is 5-15 mm.

[0018] In the above-mentioned method for controlling stress and deformation in additive manufacturing of a large-projection-area inclined surface structure, the substrate is a horizontal plate-like structure; and is used to form a support body and an inclined surface structure on the substrate.

[0019] In the above-mentioned large-projection-area inclined surface structure additive manufacturing stress deformation control method, zirconia-based ceramic shots are used during shot peening; the diameter of the zirconia-based ceramic shots is 0.5-1 mm; the shot peening distance is 120-180 mm; and the shot peening angle is not less than 50°.

[0020] In the above-mentioned large projection area inclined surface structure additive manufacturing stress deformation control method, during scanning, the laser power is 300-500W; the scanning speed is 800-1400mm / s; the filling spacing is 0.08-0.12mm; and the thickness of each layer is 20-60μm.

[0021] The beneficial effects of the present invention compared with the prior art are:

[0022] (1) The present invention can realize high-precision laser selective melting of semi-constrained open structures with large projected areas, avoiding warping and cracking caused by horizontal and vertical stresses;

[0023] (2) In order to reduce stress concentration at the contact position between the parts, the auxiliary support structure and the substrate, the present invention pre-sets compressive stress on the substrate surface by shot peening or other methods before forming, thereby reducing stress at the contact position and alleviating stress concentration;

[0024] (3) The present invention adopts a composite support structure of a grid plus a BCCZ configuration lattice in a large projection area inclined surface. The lattice support mainly provides stress restraint while reducing the contact stress between the auxiliary support and the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the formation of the inclined surface structure of the present invention;

[0026] Figure 2 A schematic diagram of a grid matrix composed of grid units of the present invention;

[0027] Figure 3 This is a schematic diagram of the BCCZ configuration lattice structure of the present invention;

[0028] Figure 4 Schematic diagram of the BCCZ configuration lattice embedded in the grid matrix of the present invention. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the embodiments.

[0030] The present invention provides a stress deformation control method for additive manufacturing of a large-projection-area inclined surface structure. The materials used in such a structure can be titanium alloys, high-temperature alloys, stainless steels, aluminum alloys, copper alloys and other materials suitable for laser selective melting forming. The method mainly realizes stress control in the vertical and horizontal directions of the component by adding a BCCZ configuration lattice-grid composite support structure in the process design stage and reducing the interface stress and forming internal stress in the process stage, so as to realize high-precision forming of such parts.

[0031] A method for controlling stress and deformation in additive manufacturing of a large projected area inclined surface structure comprises the following steps:

[0032] Grid cells and BCCZ configuration lattices designed to support inclined surface structures.

[0033] like Figure 1The grid unit and the BCCZ configuration lattice are located at the bottom of the inclined surface structure and within the projection area of ​​the inclined surface structure; when forming the inclined surface structure, the support for the inclined surface structure is achieved by realizing the grid unit and the BCCZ configuration lattice.

[0034] When the grid unit and the BCCZ configuration lattice support the inclined surface structure; the grid units are evenly distributed to form a grid matrix; gaps are left between adjacent grid units; the BCCZ configuration lattice is embedded in the gaps in the grid matrix to form a support body, such as Figure 4 shown.

[0035] like Figure 2 As shown, the grid unit is a field-shaped structure; the side length of the grid unit is 1.6-3.2 mm; and the gap between two adjacent grid units is 0.8-1.6 mm.

[0036] like Figure 3 As shown, the BCCZ configuration lattice includes a central rod 1 and four diagonal rods 2;

[0037] Among them, the central rod 1 is placed axially vertically; the four diagonal rods 2 are arranged to cross each other, and the intersection is located in the middle of each diagonal rod 2; the central rod 1 passes through the intersection of the four diagonal rods 2, and the intersection is located in the middle of the central rod 1.

[0038] The tops of the four diagonal bars 2 are flush with the top of the center bar 1; the bottoms of the four diagonal bars 2 are flush with the bottom of the center bar 1. The vertices of the four diagonal bars 2 are used as the corner points of the square, and the lines connecting the four vertices form a square; the bottom points of the four diagonal bars 2 are used as the corner points of the square, and the lines connecting the four bottom points form a square; the overall outer envelope of the BCCZ configuration lattice is a rectangular parallelepiped structure, and the side length of the rectangular parallelepiped structure is 5-15mm.

[0039] The substrate is a horizontal plate-like structure and is used to form a support body and an inclined surface structure on the substrate.

[0040] The upper surface of the substrate is shot peened.

[0041] During shot peening, zirconia-based ceramic shots are used; the diameter of the zirconia-based ceramic shots is 0.5-1 mm; the shot peening distance is 120-180 mm; and the shot peening angle is not less than 50°.

[0042] The upper surface of the substrate is scanned line by line to integrate the grid unit, BCCZ configuration lattice and inclined surface structure.

[0043] During scanning, the laser power is 300-500W; the scanning speed is 800-1400mm / s; the filling spacing is 0.08-0.12mm; and the thickness of each layer is 20-60μm.

[0044] The line-by-line scanning strategy is relatively efficient, but it will generate large internal stress after scanning large-format structures. In view of this situation, the laser scanning strategy of random island scanning filling can effectively reduce the internal stress of the forming process and reduce the overall internal stress level of the formed part.

[0045] The grid unit, the BCCZ configuration lattice and the inclined surface structure are removed from the substrate; the grid unit and the BCCZ configuration lattice are removed to complete the formation of the inclined surface structure.

[0046] The patented stress and deformation control method can realize high-precision laser selective melting of semi-constrained open structures with large projected areas, thus avoiding warping and cracking caused by horizontal and vertical stresses.

[0047] The invention can realize high-precision laser selective melting forming of a semi-constrained open structure with a large projected area inclined surface, thereby avoiding warping and cracking caused by stress in the horizontal and vertical directions.

[0048] In order to reduce stress concentration at the contact position between parts, auxiliary support structures and substrates, the present invention pre-sets compressive stress on the substrate surface by shot peening or other methods before forming, thereby reducing stress at the contact position and alleviating stress concentration.

[0049] The present invention adopts a composite support structure of a grid plus an added BCCZ configuration lattice in a large projection area inclined surface. The lattice support mainly provides stress restraint while reducing the contact stress between the auxiliary support and the substrate.

[0050] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A stress deformation control method for additive manufacturing of a large projected area inclined surface structure, characterized in that: include: Design grid cells and BCCZ configuration lattices for supporting inclined surface structures; Lay up layers to make substrate; Shot peening is performed on the upper surface of the substrate; The upper surface of the substrate is scanned line by line to form a grid unit, a BCCZ configuration lattice and an inclined surface structure in an integrated manner; The grid unit, the BCCZ configuration lattice and the inclined surface structure are removed from the substrate; the grid unit and the BCCZ configuration lattice are removed to complete the formation of the inclined surface structure.

2. The method for controlling stress and deformation in additive manufacturing of a large projected area inclined surface structure according to claim 1, characterized in that: The grid unit and the BCCZ configuration lattice are located at the bottom of the inclined surface structure and within the projection area of ​​the inclined surface structure; when forming the inclined surface structure, the inclined surface structure is supported by realizing the grid unit and the BCCZ configuration lattice.

3. The stress and deformation control method for additive manufacturing of a large projected area inclined surface structure according to claim 2, characterized in that: When the grid units and the BCCZ configuration lattice support the inclined surface structure, the grid units are evenly distributed to form a grid matrix, and gaps are left between adjacent grid units. The BCCZ configuration lattice is embedded in the gaps in the grid matrix to form a support body.

4. The stress and deformation control method for additive manufacturing of a large projected area inclined surface structure according to claim 3, characterized in that: The grid unit is a field-shaped structure; the side length of the grid unit is 1.6-3.2 mm; and the gap between two adjacent grid units is 0.8-1.6 mm.

5. The method for controlling stress and deformation in additive manufacturing of a large projected area inclined surface structure according to claim 3, characterized in that: The BCCZ configuration lattice includes a central rod (1) and four diagonal rods (2); The central rod (1) is placed axially vertically; the four diagonal rods (2) are arranged to cross each other, and the intersection is located in the middle of each diagonal rod (2); the central rod (1) passes through the intersection of the four diagonal rods (2), and the intersection is located in the middle of the central rod (1).

6. The method for controlling stress and deformation in additive manufacturing of a large projected area inclined surface structure according to claim 5, characterized in that: The tops of the four diagonal rods (2) are flush with the top of the central rod (1); and the bottoms of the four diagonal rods (2) are flush with the bottom of the central rod (1).

7. The stress and deformation control method for additive manufacturing of a large projected area inclined surface structure according to claim 6, characterized in that: The vertices of the four diagonal rods (2) serve as the corner points of the square, and the lines connecting the four vertices form a square; the base points of the four diagonal rods (2) serve as the corner points of the square, and the lines connecting the four base points form a square; the overall outer envelope of the BCCZ configuration lattice is a rectangular parallelepiped structure, and the side length of the rectangular parallelepiped structure is 5-15 mm.

8. The method for controlling stress and deformation in additive manufacturing of a large projected area inclined surface structure according to claim 3, characterized in that: The substrate is a horizontal plate-shaped structure and is used for forming a support body and an inclined surface structure on the substrate.

9. The stress deformation control method for additive manufacturing of a large projected area inclined surface structure according to claim 1, characterized in that: During shot peening, zirconia-based ceramic shots are used; the diameter of the zirconia-based ceramic shots is 0.5-1 mm; the shot peening distance is 120-180 mm; and the shot peening angle is not less than 50°.

10. The method for controlling stress and deformation in additive manufacturing of a large projected area inclined surface structure according to claim 1, characterized in that: During scanning, the laser power is 300-500W; the scanning speed is 800-1400mm / s; the filling spacing is 0.08-0.12mm; and the thickness of each layer is 20-60μm.

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