CN107866567A - The more laser of large format based on powder bed increasing material manufacturing become junction scan method - Google Patents

Abstract

The technical key points of the large-format multi-laser interface scanning method based on powder bed additive manufacturing include the following steps. The first step is to divide the large-format double laser working surface based on powder bed additive manufacturing. The first step is to rotate the diagonal around the center point, and the rotation angle changes with the number of layers of the model. The third step is to slice and layer the 3D model of the part according to the layer thickness parameters required by the laser selective melting additive manufacturing process, and Number each layer; adopt this technical scheme, realize large-scale scanning and filling through multi-laser combination, and realize the scanning path and parameter design function in the multi-model layer area, effectively solve the problem of the center and edge area of the laser selective melting forming cylinder The key technical problems such as the uniformity of the structure of the formed part and the stress and deformation ensure the uniformity of the structure of the formed part in the center and edge of the forming cylinder.

Description

Large-format multi-laser interface scanning method based on powder bed additive manufacturing

technical field

The invention relates to the technical field of laser selective melting and additive manufacturing, in particular to a large-format multi-laser transition surface scanning method based on powder bed additive manufacturing.

Background technique

Laser selective melting additive manufacturing technology is an advanced manufacturing technology based on the idea of discrete accumulation forming. It does not require molds. By discretizing the 3D model of the part into a series of orderly micron-scale thin layers along a certain direction, the high-brightness laser is used as the heat source. According to the contour information of each layer, metal powder is melted layer by layer, and parts of any complex shape are directly manufactured, only heat treatment and surface finishing parts are required; it has the characteristics of greatly reducing manufacturing processes, shortening production cycle, saving materials and funds; it is a high-end product in China. Equipment and product development provides a fast-response and precision-manufactured rapid verification advanced technology, which has broad application prospects in aerospace, nuclear industry, automobile, weapon and other active model technology upgrades, and can also be applied to electronic devices, biological implants, China's strategic emerging industries such as energy.

With the increasing size of metal parts formed by metal laser selective melting and additive forming, the problems of uniformity, stress and deformation in the forming process of the formed parts in the center and edge of the forming cylinder due to the difference in laser focusing distance and incident angle have become a major problem. Manufacturing technical problems that restrict the overall forming of large-sized parts.

Patent document CN104001915A discloses a device and a control method for high-energy beam additive manufacturing of large-scale metal parts. The "waiting time" caused by the preset powder bed when processing parts with conventional laser/electron beam selective melting technology can significantly improve the forming efficiency of high-energy beam additive manufacturing, but it is aimed at deformation and stability problems during the forming process of large-sized parts , did not elaborate on how to design the large-format slice scanning method, deformation control and coordinated control of multiple f-θ focusing systems, and the coordinated control of multiple f-θ focusing systems is difficult and costly.

When scanning in a large area, due to the deflection of the optical path, there is a large difference in the beam energy density between the central area and the edge area, and the shaping effect of the edge area is poor. In order to achieve laser additive manufacturing of large-scale parts, it is necessary to solve the cooperative control of multiple laser overlapping areas, large-scale beam deflection and system control technology.

Contents of the invention

The purpose of the present invention is to solve the problems in the above technologies, and to provide a large-format multi-laser interface scanning method based on powder bed additive manufacturing.

A large-format multi-laser transition surface scanning method based on powder bed additive manufacturing, including the following steps:

The first step is to divide the large-format dual-laser working surface based on powder bed additive manufacturing;

In the second step, the diagonal is rotated around the center point, and the rotation angle changes with the number of model layers;

In the third step, the 3D model of the parts is sliced and layered according to the layer thickness parameters required by the laser selective melting additive manufacturing process, and each layer is numbered.

Further, the area division includes that the scanning range of the laser scanning head is a square area, the center points of the laser scanning head are PC1 and PC2 respectively, the distance between the two points of PC1 and PC2 is S, the overlapping area is JM12 and JM12 is a rectangular area , the width of the overlapping area is Qs.

Further, the boundary line of the overlapping area is the scanning boundary line of the laser scanning head, and the angle of the diagonal line of the overlapping area is two critical values of the rotation angle of the diagonal line of the overlapping area, and satisfies the following relationship:

S=D－Qs (1)

tanA ₁ =D/Qs=D/(D－S) (2)

tan(180－A ₂ )＝D/(DS) (3)

A ₁ =arctan(D/(DS)) (4)

A ₂ =180-arctan(D/(DS)) (5)

Among them, S is the distance between the center points of the two laser scanning heads, D is the side length of the scanning area of the laser scanning head, Qs is the width of the overlapping area, A ₁ and A ₂ are the opposite corners of the overlapping area The angle of the line.

Further, by numbering each ply and its block area, firstly according to the working area division method, by adjusting the rotation angle of the diagonal line of the overlapping area, the boundary line of the overlapping area is changed.

Further, PC12 is the center point of the overlapping area, C12 is a diagonal line rotated from the center point of the overlapping area, CL12 and CL21 are respectively the scanning boundary lines of the laser scanning head, that is, the boundary lines of the overlapping area, A1 and A2 The angles of are respectively the angles of the diagonals of the overlap area.

Further, when the diagonal line rotates around the center point, when the rotation angle is A ₁ ≤ α ≤ _{A 2} , and the diagonal line does not intersect with the two boundary areas of the overlapping area, the laser scanning head follows the diagonal line as The dividing line of the overlapping area is divided.

Further, when the diagonal line intersects the two boundary areas of the overlapping area, the joint boundary line between the diagonal line and the two boundary areas of the overlapping area is divided. When the rotation angle α≤A ₁ , according to CL21, The intersection points of C12 and CL12 are calculated sequentially and the intersection line is used as the dividing line of the overlapping area.

Further, when the rotation angle is α≥A ₂ , the intersection line is calculated according to the order of the intersection points of CL12, C12, and CL21 as the dividing line of the overlapping area.

Further, when three laser scans are overlapped for laser selective melting scanning, the two overlapping areas are regular rectangular areas, and there are two overlapping areas of the laser scanning head, one of which is the JM12 area, and the JM2 area The two boundary areas of the laser scanning head are CL12 and CL21, the diagonal line is C12, the center point is PC12, and the other overlapping area is the JM23 area. The JM23 area is the overlapping area of the laser scanning heads LS2 and LS3. The two boundaries of the JM23 area The areas are CL23 and CL32, the diagonal line is C23, and the center point is PC23. The angles between the diagonal lines C12 and C23 passing through the fixed point in the JM12 and JM23 areas are A1 and A2 respectively, and the diagonal lines C12 and C23 respectively surround the center point PC12 and P23 for rotation.

Further, the diagonal line is rotated around the central point, and the rotation angle is 0-180 degrees, and the filling method of the overlapping area varies according to the number of different layers and the change of the rotation angle.

Advantages of the present invention:

1. Realize large-scale scanning and filling through multi-laser combination, and at the same time realize the function of scanning path and parameter design in multiple model layers;

2. Effectively solve key technical problems such as tissue uniformity, stress and deformation of the formed parts in the center and edge areas of the laser selective melting forming cylinder, and ensure the structure uniformity of the formed parts in the center and edge areas of the forming cylinder.

Description of drawings

Figure 1 is a schematic diagram of the structure of dual laser scanning;

Figure 2 is a schematic diagram of the structure of the double laser scanning overlapping area;

Fig. 3 is a schematic diagram of the structure of angle A2;

Fig. 4 is a schematic diagram of the structure of the dividing line in the overlapping area;

Fig. 5 is a schematic diagram of the principle of the overlapping area of three-laser selective melting forming;

Fig. 6 is a schematic diagram of the structure of the dividing line of the overlapping area of the three-laser selective melting forming;

Fig. 7 is a schematic structural diagram of the diagonal rotation angle 84.26° ≤ α ≤ 95.74° of the overlap area filled in the same partition;

Fig. 8 is a schematic structural diagram of the diagonal rotation angle α ≤ 84.26° of filling the overlapping area in the same partition;

Fig. 9 is a schematic structural diagram of the diagonal rotation angle α ≥ 95.74° of filling overlapping areas in the same partition.

specific embodiment

In order to make the present invention easier to understand, the technical solutions of the present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

Example 1

As shown in Figure 1-4, the large-format multi-laser interface scanning method based on powder bed additive manufacturing includes the following steps:

The first step is to divide the large-format dual-laser working surface based on powder bed additive manufacturing;

In the second step, the diagonal C12 is rotated around the center point PC12, and the rotation angle changes with the number of model layers;

In the third step, the 3D model of the parts is sliced and layered according to the layer thickness parameters required by the laser selective melting additive manufacturing process, and each layer is numbered.

Among them, the area division includes that the scanning range of the laser scanning heads LS1 and LS2 is a square area with a side length D, the center points of the laser scanning heads LS1 and LS2 are respectively PC1 and PC2, and the distance between the two points of PC1 and PC2 is S, The overlapping area is JM12 and JM12 is a rectangular area, and the width of the overlapping area JM12 is Qs.

The boundary lines CL12 and CL21 of the overlapping area JM12 are the scanning boundary lines of the laser scanning heads LS1 and LS2 respectively, the angles of the diagonal lines of the overlapping area JM12 are A1 and A2, and A1 and A2 are the diagonal lines of the overlapping area JM12 respectively Two critical values of the rotation angle of C12, and satisfy the following relationship:

S=D－Qs (1)

tanA ₁ =D/Qs=D/(D－S) (2)

tan(180－A ₂ )＝D/(DS) (3)

A ₁ =arctan(D/(DS)) (4)

A ₂ =180-arctan(D/(DS)) (5)

Among them, S is the distance between the center points of the two laser scanning heads, D is the side length of the scanning area of the laser scanning head, Qs is the width of the overlapping area, A ₁ and A ₂ are the opposite corners of the overlapping area The angle of the line.

By numbering each layer and its block area, firstly according to the working area division method, by adjusting the rotation angle of the diagonal line C12 of the overlapping area JM12, the boundary line of the overlapping area JM12 is changed.

PC12 is the center point of the overlapping area JM12, C12 is a diagonal line rotating around the center point of the overlapping area JM12, CL12 and CL21 are the scanning boundary lines of the laser scanning heads LS1 and LS2 respectively, that is, the boundary line of the overlapping area JM12, The angles of A1 and A2 are respectively the angles of the diagonal line C12 of the overlapping zone JM12.

As shown in Figure 7, when the diagonal line C12 rotates around the center point PC12, when the rotation angle is 84.26°≤α≤95.74°, when the diagonal line C12 does not intersect with the two boundary areas CL12 and CL21 of the overlapping area , the laser scanning heads LS1 and LS2 are divided according to the diagonal line C12 as the dividing line of the overlapping area JM12.

Example 2

As shown in Figure 1-4, the large-format multi-laser interface scanning method based on powder bed additive manufacturing includes the following steps:

The first step is to divide the large-format dual-laser working surface based on powder bed additive manufacturing;

In the second step, the diagonal C12 is rotated around the center point PC12, and the rotation angle changes with the number of model layers;

In the third step, the 3D model of the parts is sliced and layered according to the layer thickness parameters required by the laser selective melting additive manufacturing process, and each layer is numbered.

Among them, the area division includes that the scanning range of the laser scanning heads LS1 and LS2 is a square area, the center points of the laser scanning heads LS1 and LS2 are respectively PC1 and PC2, the distance between the two points of PC1 and PC2 is S, and the overlapping area is JM12 And JM12 is a rectangular area, and the width of the overlapping area is Qs.

The boundary line of the overlapping area JM12 is the scanning boundary line of the laser scanning head LS1 and LS2, and the angle of the diagonal line C12 of the overlapping area JM12 is the two critical values of the rotation angle of the diagonal line C12 of the overlapping area JM12, and satisfies The following relations:

S=D－Qs (1)

tanA ₁ =D/Qs=D/(D－S) (2)

tan(180－A ₂ )＝D/(DS) (3)

A ₁ =arctan(D/(DS)) (4)

A ₂ =180-arctan(D/(DS)) (5).

By numbering each layer and its block area, firstly according to the working area division method, by adjusting the rotation angle of the diagonal line C12 of the overlapping area JM12, the boundary line of the overlapping area JM12 is changed.

PC12 is the center point of the overlapping area JM12, C12 is the diagonal line rotated by the center point PC12 of the overlapping area JM12, CL12 and CL21 are the scanning boundary lines of the laser scanning heads LS1 and LS2 respectively, that is, the boundary line of the overlapping area JM12 , the angles of A1 and A2 are respectively the angles of the diagonal line C12 of the overlapping zone JM12.

As shown in Figure 8, when the diagonal line C12 intersects the two boundary areas of the overlapping area JM12, the joint boundary line between the diagonal line C12 and the two boundary areas of the overlapping area JM12 is divided, and when the rotation angle α≤ At 84.26°, the boundary line of the n-1th layer of the overlapping area JM12 formed by double laser selective melting and partition filling, the dividing line of the overlapping area JM12 is calculated according to the order of intersection points of CL21, C12, and CL12 as the overlapping area The dividing line of JM12.

Example 3

As shown in Figure 1-4, the large-format multi-laser interface scanning method based on powder bed additive manufacturing includes the following steps:

The first step is to divide the large-format dual-laser working surface based on powder bed additive manufacturing;

In the second step, the diagonal C12 is rotated around the center point PC12, and the rotation angle changes with the number of model layers;

In the third step, the 3D model of the parts is sliced and layered according to the layer thickness parameters required by the laser selective melting additive manufacturing process, and each layer is numbered.

Among them, the area division includes that the scanning range of the laser scanning heads LS1 and LS2 is a square area, the center points of the laser scanning heads LS1 and LS2 are respectively PC1 and PC2, the distance between the two points of PC1 and PC2 is S, and the overlapping area is JM12 And JM12 is a rectangular area, and the width of the overlapping area is Qs.

The boundary line of the overlapping area JM12 is the scanning boundary line of the laser scanning head LS1 and LS2, and the angle of the diagonal line C12 of the overlapping area JM12 is the two critical values of the rotation angle of the diagonal line C12 of the overlapping area JM12, and satisfies The following relationship:

S=D－Qs (1)

tanA ₁ =D/Qs=D/(D－S) (2)

tan(180－A ₂ )＝D/(DS) (3)

A ₁ =arctan(D/(DS)) (4)

A ₂ =180-arctan(D/(DS)) (5).

By numbering each layer and its block area, firstly according to the working area division method, by adjusting the rotation angle of the diagonal line C12 of the overlapping area JM12, the boundary line of the overlapping area JM12 is changed.

PC12 is the center point of the overlapping area JM12, C12 is the diagonal line rotated by the center point PC12 of the overlapping area JM12, CL12 and CL21 are the scanning boundary lines of the laser scanning heads LS1 and LS2 respectively, that is, the boundary line of the overlapping area JM12 , the angles of A1 and A2 are respectively the angles of the diagonal line C12 of the overlapping zone JM12.

As shown in Figure 9, when the rotation angle is α ≥ 95.74°, the boundary line of the n+1th layer of the overlapping area JM12 formed by dual laser selective melting and the partition filling, the boundary line of the overlapping area JM12 is the intersection of CL12, C12, and CL21 Sequentially calculate the intersection line as the dividing line of the overlapping area JM12.

Example 4

As shown in Figure 1-4, the large-format multi-laser interface scanning method based on powder bed additive manufacturing includes the following steps:

The first step is to divide the large-format dual-laser working surface based on powder bed additive manufacturing;

In the second step, the diagonal C12 is rotated around the center point PC12, and the rotation angle changes with the number of model layers;

In the third step, the 3D model of the parts is sliced and layered according to the layer thickness parameters required by the laser selective melting additive manufacturing process, and each layer is numbered.

Among them, the area division includes that the scanning range of the laser scanning heads LS1 and LS2 is a square area, the center points of the laser scanning heads LS1 and LS2 are respectively PC1 and PC2, the distance between the two points of PC1 and PC2 is S, and the overlapping area is JM12 And JM12 is a rectangular area, and the width of the overlapping area is Qs.

The boundary line of the overlapping area JM12 is the scanning boundary line of the laser scanning head LS1 and LS2, and the angle of the diagonal line C12 of the overlapping area JM12 is the two critical values of the rotation angle of the diagonal line C12 of the overlapping area JM12, and satisfies The following relationship:

S=D－Qs (1)

tanA ₁ =D/Qs=D/(D－S) (2)

tan(180－A ₂ )＝D/(DS) (3)

A ₁ =arctan(D/(DS)) (4)

A ₂ =180-arctan(D/(DS)) (5).

By numbering each layer and its block area, firstly according to the working area division method, by adjusting the rotation angle of the diagonal line C12 of the overlapping area JM12, the boundary line of the overlapping area JM12 is changed.

PC12 is the center point of the overlapping area JM12, C12 is the diagonal line rotated by the center point PC12 of the overlapping area JM12, CL12 and CL21 are the scanning boundary lines of the laser scanning heads LS1 and LS2 respectively, that is, the boundary line of the overlapping area JM12 , the angles of A1 and A2 are respectively the angles of the diagonal line C12 of the overlapping zone JM12.

As shown in Figure 5-6, when three laser scans are overlapped for laser selective melting scanning, there are two overlapping areas of the laser scanning heads LS1, LS2, and LS3, one of which is the JM12 area, and the two overlapping areas of the JM2 area The boundary area of the bar is CL12 and CL21, the diagonal line is C12, the center point is PC12, and the other overlapping area is the JM23 area, which is the overlapping area of the laser scanning heads LS2 and LS3, and the two overlapping areas are regular Rectangular area, the two boundary areas of JM23 area are CL23 and CL32, the diagonal line is C23, the center point is PC23, the angles between JM12 and JM23 area passing through the fixed point diagonal line C12 and C23 are A1 and A2 respectively, and the diagonal line is A1 and A2 respectively. Lines C12 and C23 are rotated about center points PC12 and P23, respectively.

The diagonal line C12 rotates around the center point PC12, and the rotation angle is 0-180 degrees. The filling method of the overlapping area varies according to the number of different layers and the change of the rotation angle.

According to the above content, those in the technical field can effectively promote the application of multi-laser large-format collaborative manufacturing such as four-laser and five-laser, which greatly improves the forming efficiency, effectively solves key problems such as organization and defects, stress and deformation in the forming process, and realizes large-scale Parts are manufactured by selective laser melting.

Claims (10)

1. The large-format multi-laser variable joint surface scanning method based on powder bed additive manufacturing, is characterized in that: comprise the following steps, The first step is to divide the large-format dual-laser working surface based on powder bed additive manufacturing; In the second step, the diagonal is rotated around the center point, and the rotation angle changes with the number of model layers; In the third step, the 3D model of the parts is sliced and layered according to the layer thickness parameters required by the laser selective melting additive manufacturing process, and each layer is numbered. 2. The large-format multi-laser transition surface scanning method based on powder bed additive manufacturing according to claim 1, wherein the area division includes that the scanning range of the laser scanning head is a square area, and the center points of the laser scanning head are respectively PC1 and PC2, the distance between PC1 and PC2 is S, the overlapping area is JM12 and JM12 is a rectangular area, and the width of the overlapping area is Qs. 3. The large-format multi-laser transition surface scanning method based on powder bed additive manufacturing according to claim 1, characterized in that: the boundary line of the overlapping area is the scanning boundary line of the laser scanning head, and the pair of overlapping areas The angles of the diagonals are the two critical values of the rotation angles of the diagonals of the overlapping area, and satisfy the following relationship: S=D－Qs (1) tanA ₁ =D/Qs=D/(D－S) (2) tan(180－A ₂ )＝D/(DS) (3) A ₁ =arctan(D/(DS)) (4) A ₂ =180-arctan(D/(DS)) (5) Among them, S is the distance between the center points of the two laser scanning heads, D is the side length of the scanning area of the laser scanning head, Qs is the width of the overlapping area, A ₁ and A ₂ are the opposite corners of the overlapping area The angle of the line. 4. The large-format multi-laser transition surface scanning method based on powder bed additive manufacturing according to claim 1, characterized in that: by numbering each layer and its block area, first according to the working area division method, By adjusting the rotation angle of the diagonal line of the overlapping area, the boundary line of the overlapping area is changed. 5. The large-format multi-laser transition surface scanning method based on powder bed additive manufacturing according to claim 2, characterized in that: PC12 is the center point of the overlapping area, and C12 is a pair rotated by the center point of the overlapping area Diagonal lines, CL12 and CL21 are the scanning boundary lines of the laser scanning head, that is, the boundary lines of the overlapping area, and the angles of A1 and A2 are the angles of the diagonal lines of the overlapping area. 6. The large-format multi-laser transition surface scanning method based on powder bed additive manufacturing according to claim 1, characterized in that: when the diagonal rotates around the center point, the rotation angle is A ₁ ≤ α ≤ _{A 2} , when the diagonal line does not intersect with the two boundary areas of the overlapping area, the laser scanning head divides the diagonal line as the dividing line of the overlapping area. 7. The large-format multi-laser transition surface scanning method based on powder bed additive manufacturing according to claim 1, characterized in that: when the diagonal line intersects with the two boundary areas of the overlapping area, the diagonal line and the The joint boundary line of the two boundary areas of the overlapping area is divided. When the rotation angle α≤A ₁ , the intersection line is calculated according to the order of intersection points of CL21, C12, and CL12 as the dividing line of the overlapping area. 8. The large-format multi-laser transition surface scanning method based on powder bed additive manufacturing according to claim 1, characterized in that: when the rotation angle is α≥A ₂ , the order of intersections of CL12, C12, and CL21 is calculated The intersection line serves as the dividing line of the overlapping area. 9. The large-format multi-laser joint surface scanning method based on powder bed additive manufacturing according to claim 1, characterized in that: when three laser scans are overlapped to perform laser selective melting scanning, the two overlapping areas are both It is a regular rectangular area, and there are two overlapping areas of the laser scanning head, one of which is the JM12 area, the two boundary areas of the JM2 area are CL12 and CL21, the diagonal line is C12, the center point is PC12, and the other The overlapping area is the JM23 area, and the JM23 area is the overlapping area of the laser scanning heads LS2 and LS3. The two border areas of the JM23 area are CL23 and CL32, the diagonal line is C23, and the center point is PC23. The JM12 and JM23 areas pass through the fixed point The angles between the diagonals C12 and C23 are A1 and A2 respectively, and the diagonals C12 and C23 rotate around the center points PC12 and P23 respectively. 10. The large-format multi-laser transition surface scanning method based on powder bed additive manufacturing according to claim 1, characterized in that: the diagonal rotates around the center point, the rotation angle is 0-180 degrees, and the overlapping area The filling method of the layer varies according to the layer number and the rotation angle.