Large-format, high-efficiency, high-precision laser selective melting forming equipment and method

Abstract

The present invention discloses a large-format, high-efficiency, high-precision laser selective melting forming device and method, which belongs to the field of advanced manufacturing technology. The device includes a forming cylinder and a laser processing unit assembly, each of which includes a plurality of laser processing units arrayed along the width direction of the metal powder layer; each laser processing unit includes a plurality of processing modules, which are composed of components such as a dynamic focusing galvanometer and a collimating mirror, and are externally connected to an optical fiber laser with adjustable spot mode; when the device is used for SLM forming of metal parts, each laser processing unit can simultaneously use multiple groups of kilowatt-class high-power lasers / hundred-watt-class high-power lasers to collaboratively form the corresponding metal powder layer sub-area. Through the large-format, high-efficiency, high-precision laser selective melting forming device of the present invention, the forming efficiency can be significantly improved and the forming format can be expanded under the premise of ensuring the SLM forming accuracy, thereby realizing low-cost, batch SLM forming of large-size metal parts.

Description

Technical Field

[0001] The present invention belongs to the field of advanced manufacturing technology, and more specifically, relates to a large-format, high-efficiency, high-precision laser selective melting forming device and method. Background Art

[0002] Selective Laser Melting (SLM) is one of the most promising 3D printing technologies for metal parts. It uses a galvanometer to drive a laser beam to melt metal powder layer by layer. It does not require any molds or tooling. It can achieve high-performance, structural and functional integrated forming of almost any complex metal parts with only a three-dimensional digital model of the metal parts. However, the low forming efficiency and small forming area of ​​SLM technology seriously restrict its large-scale industrial application.

[0003] In order to solve the above bottleneck problems of SLM technology, domestic and foreign research institutions have mainly proposed two technical routes:

[0004] The first technical route is to divide the metal powder layer into several sub-areas and use multiple galvanometers to perform synchronous laser melting forming on these sub-areas. This type of solution can not only improve the forming efficiency, but also expand the forming area by increasing the number of galvanometers.

[0005] The second technical route is to use a kilowatt-class high-power laser to replace the hundred-watt-class low-power laser commonly used in SLM technology, thereby increasing the laser scanning speed, laser scanning spacing and powder layer thickness while ensuring that the metal powder layer is fully melted, thereby improving the forming efficiency. Since the metal parts formed by SLM are stacked layer by layer by laser cladding, the increase in laser scanning spacing and powder layer thickness will inevitably lead to a decrease in forming accuracy. In response to this problem, domestic and foreign researchers have further proposed a high / low power laser collaborative SLM forming method. This method divides the digital model of metal parts into two parts: one is the part with higher forming accuracy requirements, using the hundred-watt-class low-power laser commonly used in SLM technology to achieve high-precision forming; the other is the area with higher forming efficiency requirements, using a kilowatt-class high-power laser to achieve high-efficiency forming. When using this method to form metal parts, high and low power laser forming are used alternately according to the partitioning of the digital model of the parts, thereby taking into account both forming efficiency and forming accuracy to a certain extent.

[0006] So far, combining the above two technical routes, that is, dividing the metal powder layer into several sub-areas, each of which is formed by a group of high / low power lasers, has become the latest development direction of industrial-grade SLM equipment. However, for any sub-area, its forming process can only be completed by a group of high / low power lasers, and the improvement in forming efficiency is still not enough to meet the large-scale, low-cost manufacturing needs of large-size metal parts. Therefore, it is urgent to explore new methods to further improve the forming efficiency of SLM technology.

[0007] In summary, in view of the various existing problems of selective laser melting (SLM) technology, the invention of a large-format, high-efficiency, and high-precision SLM forming equipment and method is of great significance for the large-scale promotion and application of SLM technology. Summary of the invention

[0008] In view of the defects of the prior art, the purpose of the present invention is to provide a large-format, high-efficiency and high-precision laser selective melting forming equipment and method, aiming to solve the problems in the prior art of low forming efficiency of laser selective melting and difficulty in meeting the low-cost and large-scale manufacturing of large-size metal parts.

[0009] To achieve the above-mentioned object, the present invention provides a large-format, high-efficiency, high-precision laser selective melting forming device, comprising a forming cylinder and a laser processing unit assembly, wherein:

[0010] The forming cylinder is used to lay metal powder layers layer by layer;

[0011] The laser processing unit assembly is used for SLM forming of the metal powder layer, and is located above the forming cylinder. The number of the laser processing unit assemblies is M, M≥1, and they can reciprocate along the length direction of the metal powder layer. Each of the laser processing unit assemblies comprises N laser processing units arrayed along the width direction of the metal powder layer, N≥2. The forming width of each laser processing unit is also arrayed along the width direction of the metal powder layer and is spliced ​​with each other, so that the spliced ​​forming widths of each laser processing unit cover the metal powder layer along the width direction of the metal powder layer;

[0012] Each of the laser processing units includes P processing modules, P≥2, and each of the processing modules is externally connected to an optical fiber laser with adjustable spot mode, and the optical fiber laser with adjustable spot mode can output kilowatt-level high-power laser / hundred-watt-level low-power laser; the scanning range of the kilowatt-level high-power laser / hundred-watt-level low-power laser can cover the entire forming width of the corresponding laser processing unit.

[0013] Furthermore, each of the processing modules includes a collimator and a dynamic focusing galvanometer; the collimator is connected to the optical fiber head of an adjustable spot mode optical fiber laser through a QBH standard interface, the maximum output laser power of the adjustable spot mode optical fiber laser is greater than or equal to 1kW, and the collimator is used to collimate and expand the laser beam output by the adjustable spot mode optical fiber laser, and input the collimated and expanded laser beam to the dynamic focusing galvanometer; the dynamic focusing galvanometer is used to drive the collimated and expanded laser beam to selectively melt the metal powder layer according to a preset scanning trajectory, and is used to dynamically adjust the spot diameter of the laser beam on the surface of the metal powder layer.

[0014] Furthermore, an envelope size K of the P processing modules along the width direction of the metal powder layer is less than or equal to an envelope size L of the forming width of the laser processing unit along the width direction of the metal powder layer.

[0015] Furthermore, each laser processing unit contains 2 processing modules, which are arrayed in 1 column along the width direction of the metal powder layer; or, each laser processing unit contains 4 processing modules, which are arrayed in 2 columns along the width direction of the metal powder layer, and these 2 columns of processing modules are arranged symmetrically.

[0016] Furthermore, the number M of the laser processing unit assemblies satisfies: 1≤M≤5; the number N of laser processing units contained in each of the laser processing unit assemblies satisfies: 2≤N≤5.

[0017] Furthermore, the maximum output power of the optical fiber laser with adjustable spot mode is greater than or equal to 2 kW, and can realize the alternating output of Gaussian mode laser beam, annular mode laser beam, and Gaussian / annular combination mode laser beam.

[0018] The present invention also provides a method for SLM forming of large-sized metal parts, the method comprising the following steps:

[0019] S1. Divide the three-dimensional digital model of the metal part into a high-precision forming part and a high-efficiency forming part according to the processing accuracy, and perform layered slicing on the two parts respectively;

[0020] S2. According to the number M of laser processing unit assemblies, the number N of laser processing units contained in each laser processing unit assembly, and the forming width, the metal powder layer is divided into a sub-region array including Q×N sub-regions, Q≥M+1; wherein the sub-region array has N rows along the width direction of the metal powder layer and Q columns along the length direction of the metal powder layer; the size of each sub-region along the width direction of the metal powder layer is equal to the envelope size L of the forming width of the laser processing unit along the width direction of the metal powder layer; the size of each sub-region along the length direction of the metal powder layer is less than or equal to the envelope size of the forming width of the laser processing unit along the length direction of the metal powder layer;

[0021] S3. Allocate a laser processing unit for SLM forming to each sub-region: each laser processing unit assembly is responsible for forming at least one column of sub-region arrays, and all laser processing unit assemblies are responsible for forming all Q columns of sub-region arrays; the N sub-regions contained in each column of sub-region arrays correspond one-to-one to the laser processing units of the corresponding laser processing unit assembly, that is, each sub-region is formed by a corresponding laser processing unit;

[0022] S4. Plan the scanning trajectory of the low-power laser of the hundred-watt level and the high-power laser of the kilowatt level:

[0023] The 100-watt low-power laser scanning trajectory is planned in the following manner: According to the division scheme and layered slicing data of the high-precision forming part of the three-dimensional digital model of the metal part, as well as the sub-area division scheme and laser processing unit allocation scheme of the metal powder layer, the 100-watt low-power laser scanning trajectory is planned for each sub-area:

[0024] First, each sub-region is equally divided into X×P high-precision forming partitions, where X is an integer greater than or equal to 1; then, the i-th, P+i-th, ..., (X-1)×P+i-th high-precision forming partitions of each sub-region, 1≤i≤P, are assigned to the i-th processing module of the corresponding laser processing unit for forming; further, based on the layered slicing data of the high-precision forming part of the three-dimensional digital model of the metal part and the position distribution of the high-precision forming partitions of each sub-region, a low-power laser scanning trajectory of a hundred-watt level for the processing module corresponding to each high-precision forming partition is generated;

[0025] The kilowatt-class high-power laser scanning trajectory is planned in the following manner: According to the division scheme and layered slicing data of the three-dimensional digital model of the metal part and the high-efficiency forming part, as well as the sub-area division scheme of the metal powder layer and the laser processing unit allocation scheme, a kilowatt-class high-power laser scanning trajectory is planned for each sub-area:

[0026] First, each sub-region is equally divided into Y×P high-efficiency forming partitions, where Y is an integer greater than or equal to 1; then, the i-th, P+i-th, ..., (Y-1)×P+i (P≥i≥1)-th high-efficiency forming partitions of each sub-region are assigned to the i-th processing module of the corresponding laser processing unit for forming; further, based on the layered slicing data of the high-efficiency forming part of the three-dimensional digital model of the metal part and the position distribution of the high-efficiency forming partitions of each sub-region, a kilowatt-level high-power laser scanning trajectory of the processing module corresponding to each high-efficiency forming partition is generated;

[0027] S5, laying a first layer of metal powder in the forming cylinder, and moving the M laser processing unit components of the equipment to the top of a corresponding column of sub-area arrays;

[0028] S6. According to the 100-watt low-power laser scanning trajectory of each processing module generated in step S4, the M×N laser processing units in the equipment are used to synchronously carry out high-precision SLM forming on the M×N sub-areas corresponding to the current positions of the M×N laser processing units; wherein, when each laser processing unit forms the sub-area it is responsible for, the P processing modules contained in the laser processing unit simultaneously form the corresponding high-precision forming partition in the sub-area; wherein, the i-th processing module forms the i-th, P+i-th, ..., (X-1)×P+i-th high-precision forming partitions in sequence;

[0029] S7. According to the kilowatt-class high-power laser scanning trajectory generated in step S4, high-efficiency SLM forming is synchronously performed on the M×N sub-areas corresponding to the current positions of the M×N laser processing units; wherein, when each laser processing unit forms the sub-area it is responsible for, the P processing modules contained in the laser processing unit simultaneously form the corresponding high-efficiency forming partition in the sub-area; wherein, the i-th processing module forms the i-th, P+i-th, ..., (Y-1)×P+i-th high-efficiency forming partitions in sequence;

[0030] S8, moving the M laser processing unit assemblies of the equipment to the corresponding sub-region columns that have not yet been formed, and completing the forming of these sub-region columns with reference to steps S7 and S8, thereby completing the forming of the first metal powder layer;

[0031] S9. Referring to steps S5, S6, S7 and S8, the subsequent metal powder layer laying and SLM forming are completed in sequence, thereby completing the SLM forming of large-size metal parts.

[0032] Furthermore, in steps S6 and S7, after the i-th processing module completes the forming of the i-th, P+i-th,…, (X-1)×P+i-th high-precision forming partitions in sequence, it does not wait for other processing modules to complete the forming of the corresponding high-precision forming partitions, but the processing module performs the forming of the i-th, P+i-th,…, (Y-1)×P+i-th high-efficiency forming partitions in sequence.

[0033] Furthermore, in step S6, by controlling the laser mode and laser output power of the optical fiber laser with adjustable spot mode and the focusing parameters of the dynamic focusing galvanometer, the laser power of the hundred-watt low-power laser used in high-precision forming partition forming is made ≤500W, and the spot mode is Gaussian mode, and the spot diameter on the surface of the metal powder layer is ≤100μm.

[0034] Furthermore, in step S7, by controlling the laser mode and laser output power of the spot mode adjustable fiber laser and the focusing parameters of the dynamic focusing galvanometer, the laser power of the kilowatt-class high-power laser used in the high-efficiency forming partition forming is ≥2kW, the spot mode is an annular mode or a Gaussian / annular combination mode, and the spot diameter on the surface of the metal powder layer is ≥200μm.

[0035] Furthermore, in step S4, the value of X is 2≤X≤5, and the value of Y is 2≤Y≤5; the shapes of the high-precision forming partition and the high-efficiency forming partition are both rectangular.

[0036] Furthermore, in the high-precision forming of steps S4 and S6, the X×P high-precision forming partitions of each sub-area are sorted according to the total length of their respective hundred-watt-class low-power laser scanning trajectories; specifically, the higher the total length of the hundred-watt-class low-power laser scanning trajectories, the higher the ranking of the high-precision forming partitions is when numbering; in the high-efficiency forming of steps S4 and S7, the Y×P high-efficiency forming partitions of each sub-area are sorted according to the total length of their respective kilowatt-class high-power laser scanning trajectories; specifically, the higher the total length of the kilowatt-class high-power laser scanning trajectories, the higher the ranking of the high-efficiency forming partitions is when numbering.

[0037] In general, the above technical solution conceived by the present invention has the following beneficial effects compared with the prior art:

[0038] 1. The present invention optimizes the design of the laser processing unit components of the SLM equipment, especially by utilizing the characteristics of large dynamic focusing galvanometer forming area and dynamically adjustable spot diameter, as well as the advantages of flexible output mode of adjustable spot mode fiber laser, so that each sub-area of ​​the metal powder layer can be formed by multiple groups of kilowatt-level high-power lasers / hundred-watt-level low-power lasers at the same time, breaking through the technical bottleneck of the existing SLM technology that each sub-area of ​​the metal powder layer can only be formed by one group of kilowatt-level high-power lasers / hundred-watt-level low-power lasers, thereby achieving a revolutionary improvement in SLM forming efficiency while ensuring forming accuracy. On this basis, through the reasonable array of laser processing units and sub-station processing, a substantial expansion of the forming area is achieved, providing an effective solution for large-scale, low-cost SLM forming of large-size metal parts;

[0039] 2. The present invention further divides each sub-area of ​​the metal powder layer into a number of high-precision forming areas and high-efficiency forming areas, allocates corresponding processing modules, and formulates a corresponding forming sequence. It can not only carry out synchronous forming of multiple beams of hundred-watt lasers or synchronous forming of multiple beams of kilowatt-level high-power lasers on the same sub-area under the premise of avoiding laser interference, but also carry out forming of multiple beams of hundred-watt-level low-power lasers and forming of multiple beams of kilowatt-level high-power lasers on the same sub-area at the same time under the premise of avoiding laser interference, thereby further improving the forming efficiency under the premise of ensuring the forming quality;

[0040] 3. Based on a large amount of practice, the present invention optimizes the number of laser processing unit assemblies, the number of laser processing units contained in each laser processing unit assembly, the number and arrangement of processing modules contained in each laser processing unit, the number of high-precision forming partitions and high-efficiency forming partitions contained in each sub-area of ​​the metal powder layer and their matching relationship with the processing modules, as well as their forming sequence and forming parameters, thereby further improving the forming efficiency and forming accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic diagram of the arrangement of a laser processing unit assembly of a large-format, high-efficiency, high-precision SLM forming device and the laser processing units contained therein provided by the present invention;

[0042] Figure 2 It is a schematic diagram of a processing module included in a laser processing unit of a large-format, high-efficiency, high-precision SLM forming device provided by the present invention;

[0043] Figure 3 It is a schematic diagram of the arrangement of multiple processing modules contained in a laser processing unit of a large-format, high-efficiency, high-precision SLM forming device provided by the present invention;

[0044] Figure 4 It is another schematic diagram of the arrangement of multiple processing modules contained in the laser processing unit of a large-format, high-efficiency, high-precision SLM forming device provided by the present invention;

[0045] Figure 5 It is a principle diagram of a laser processing unit of a large-format, high-efficiency, high-precision SLM forming device provided by the present invention that can simultaneously use multiple groups of laser forming within its forming format;

[0046] Figure 6 (a) and (b) are schematic diagrams of high-precision forming partitions and high-efficiency forming partitions of the metal powder layer sub-areas;

[0047] Figure 7It is a schematic diagram of the arrangement of a laser processing unit assembly of a large-format, high-efficiency, high-precision SLM forming device and the laser processing units contained therein provided in Example 1 of the present invention;

[0048] Figure 8 It is a schematic diagram of the arrangement of multiple processing modules contained in a laser processing unit of a large-format, high-efficiency, and high-precision SLM forming device provided in Example 1 of the present invention;

[0049] Fig. 9 (a) and (b) are schematic diagrams of high-precision forming zoning and high-efficiency forming zoning division of a metal powder layer sub-region in a large-format, high-efficiency, high-precision SLM forming method provided in Example 1 of the present invention;

[0050] Fig.10 It is a schematic diagram of the arrangement of a laser processing unit assembly of a large-format, high-efficiency, high-precision SLM forming device and the laser processing units contained therein provided in Example 2 of the present invention;

[0051] Fig.11 It is a schematic diagram of the arrangement of multiple processing modules contained in a laser processing unit of a large-format, high-efficiency, high-precision SLM forming device provided in Example 2 of the present invention;

[0052] Fig.12 (a) and (b) are schematic diagrams of high-precision forming zoning and high-efficiency forming zoning division of a metal powder layer sub-area in a large-format, high-efficiency, and high-precision SLM forming method provided in Example 2 of the present invention.

[0053] In all the drawings, the same figure marks are used to represent the same elements or structures. The structures corresponding to the digital marks in the drawings are: 1-metal powder layer, 2-forming format, 3-laser processing unit, 4-laser beam, 5-collimating mirror, 6-dynamic focusing galvanometer, 7-sub-area, 8-high-precision forming partition, 9-high-efficiency forming partition, 10-scanning field; 11-scanning field overlapping area. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0055] The present invention provides a large-format, high-efficiency, high-precision SLM forming device, comprising a forming cylinder and a laser processing unit assembly. Figure 1As shown, the forming cylinder is used to lay the metal powder layer 1 layer by layer, and the laser processing unit assembly is located above the metal powder layer 1, which is used for SLM forming of the metal powder layer. The number of laser processing unit assemblies is M, M ≥ 1, and they can reciprocate along the length direction of the metal powder layer. Each laser processing unit assembly includes N laser processing units arrayed along the width direction of the metal powder layer, N ≥ 2, and the forming width of each laser processing unit is also arrayed along the width direction of the metal powder layer and spliced ​​together, so that the spliced ​​forming widths of each laser processing unit cover the metal powder layer along the width direction of the metal powder layer.

[0056] Each laser processing unit includes P processing modules, P≥2, and each processing module is externally connected to an adjustable spot mode fiber laser, which can output kilowatt-level high-power laser / hundred-watt-level low-power laser; the scanning range of the kilowatt-level high-power laser / hundred-watt-level low-power laser can cover the entire forming width of the corresponding laser processing unit.

[0057] like Figure 2 As shown, each processing module includes a collimator 5 and a dynamic focusing galvanometer 6. The collimator 5 is connected to the fiber head of a spot mode adjustable fiber laser with a maximum laser output power of not less than 1 kW through a QBH standard interface, collimates and expands the laser beam 4 output by the laser, and inputs the collimated and expanded laser beam 4 to the dynamic focusing galvanometer 6.

[0058] The dynamic focusing galvanometer 6 is used to drive the collimated and expanded laser beam 4 to selectively melt the metal powder layer 1 according to a preset scanning trajectory, and is used to dynamically adjust the spot diameter of the laser beam 4 on the surface of the metal powder layer 1. Among them, the spot mode adjustable fiber laser adopts a standardized product, has a real-time adjustment function of the laser beam mode, and can realize the alternating output of Gaussian mode laser beam, annular mode laser beam, and Gaussian / annular combination mode laser beam.

[0059] like Figure 3 As shown, the P processing modules of the laser processing unit are arranged in a row along the width direction of the metal powder layer. Figure 4 As shown, the P processing modules of the laser processing unit are arranged in two rows along the width direction of the metal powder layer, and the two rows of processing modules are arranged symmetrically. Figure 1 , 3 As shown in FIG. 4 , the envelope size K of the P processing modules along the width direction of the metal powder layer is made smaller than or equal to the envelope size L of the forming width 2 of the laser processing unit 3 along the width direction of the metal powder layer 1 , thereby avoiding position interference between adjacent laser processing units 3 in the same laser processing unit assembly.

[0060] The technical effects achieved through the above settings are as follows Figure 5As shown, specifically, by utilizing the characteristic that the scanning field 10 of the dynamic focusing galvanometer 6 is relatively large (much larger than the projection area of ​​the dynamic focusing galvanometer 6 on the surface of the metal powder layer 1), the dynamic focusing galvanometers 6 arranged together have a relatively large scanning field overlapping area 11, and a forming format 2 is set in the scanning field overlapping area 11, so that each laser processing unit 3 can simultaneously use multiple groups of kilowatt-level high-power / hundred-watt-level low-power lasers 4 for forming within its forming format 2; at this time, the scanning range of each group of kilowatt-level high-power / hundred-watt-level low-power lasers 4 can cover the entire forming format 2 of the corresponding laser processing unit 3.

[0061] In order to improve the forming efficiency and reduce the manufacturing cost of the equipment, and to facilitate the arrangement and installation of the various components of the equipment, the number M of laser processing unit assemblies is optimized to: 1≤M≤5; the number N of laser processing units 3 contained in each laser processing unit assembly is optimized to: 2≤N≤5; the number of processing modules contained in each laser processing unit 3 is optimized to 2, and the array is 1 column along the width direction of the metal powder layer 1; or, the number of processing modules contained in each laser processing unit 3 is 4, and the array is 2 columns along the width direction of the metal powder layer 1, and the 2 columns of processing modules are symmetrically arranged.

[0062] Based on the above large-format, high-efficiency, and high-precision SLM equipment, the present invention proposes a method for SLM forming of large-size metal parts, comprising the following steps:

[0063] S1. Divide the three-dimensional digital model of the metal part into two parts and perform layered slicing processing respectively: one is the high-precision forming part with complex structure and high forming accuracy requirements, and the other is the high-efficiency forming part with relatively simple structure and relatively low forming accuracy requirements;

[0064] S2. According to the number M of laser processing unit assemblies, the number N of laser processing units 3 contained in each laser processing unit assembly, and the forming width 2, the metal powder layer 1 is divided into a sub-region array including Q×N sub-regions 7, (Q≥M+1); wherein the sub-region array has N rows along the width direction of the metal powder layer 1 and Q columns along the length direction of the metal powder layer 1; the size of each sub-region 7 along the width direction of the metal powder layer 1 is equal to the envelope size L of the forming width 2 of the laser processing unit 3 along the width direction of the metal powder layer 1; the size of each sub-region 7 along the length direction of the metal powder layer 1 is less than or equal to the envelope size of the forming width 2 of the laser processing unit 3 along the length direction of the metal powder layer 1;

[0065] S3. Allocate a laser processing unit 3 for SLM forming to each sub-region 7: Specifically, each laser processing unit assembly is responsible for the forming of at least one column of sub-regions 7, and M laser processing units are responsible for the forming of all Q columns of sub-regions 7; the N sub-regions 7 contained in each column of the sub-region array correspond one-to-one to the N laser processing units 3 contained in the corresponding laser processing unit assembly, and the corresponding one laser processing unit 3 is responsible for the forming;

[0066] S4. Plan the scanning trajectory of the low-power laser of the hundred-watt level and the high-power laser of the kilowatt level:

[0067] The 100-watt low-power laser scanning trajectory is planned in the following manner: According to the division scheme and layered slicing data of the high-precision forming part of the three-dimensional digital model of the metal part, as well as the sub-area 7 division scheme of the metal powder layer and the laser processing unit 3 allocation scheme, the 100-watt low-power laser scanning trajectory is planned for each sub-area 7: Specifically, Figure 6 As shown in (a), first, each sub-region 7 is evenly divided into X×P high-precision forming partitions 8, where X is an integer greater than or equal to 1; then, the i-th, P+i-th, ..., (X-1)×P+i-th high-precision forming partitions 8 of each sub-region 7, 1≤i≤P, are assigned to the i-th processing module of the corresponding laser processing unit 3 for forming; further, based on the layered slicing data of the high-precision forming part of the three-dimensional digital model of the metal part and the position distribution of the high-precision forming partition 8 of each sub-region 7, a low-power laser scanning trajectory of a hundred-watt level for the processing module corresponding to each high-precision forming partition 8 is generated;

[0068] The kilowatt-class high-power laser scanning trajectory is planned in the following manner: according to the division scheme and layered slicing data of the high-efficiency forming part of the three-dimensional digital model of the metal part, as well as the sub-area 7 division scheme of the metal powder layer and the laser processing unit 3 allocation scheme, a kilowatt-class high-power laser scanning trajectory is planned for each sub-area 7: Specifically, as Figure 6 As shown in (b), first, each sub-region 7 is equally divided into Y×P high-efficiency forming partitions 9, where Y is an integer greater than or equal to 1; then, the i-th, P+i-th, ..., (Y-1)×P+i-th high-efficiency forming partitions 9 of each sub-region 7, 1≤i≤P, are assigned to the i-th processing module of the corresponding laser processing unit 3 for forming; further, based on the layered slicing data of the high-efficiency forming part of the three-dimensional digital model of the metal part and the position distribution of the high-efficiency forming partitions 9 of each sub-region 7, a kilowatt-level high-power laser scanning trajectory of the processing module corresponding to each high-efficiency forming partition 9 is generated;

[0069] S5, laying the first metal powder layer 1 in the forming cylinder, and moving the M laser processing unit components of the equipment to the top of a corresponding column of sub-areas 7;

[0070] S6. According to the 100-watt low-power laser scanning trajectory of each processing module generated in step S4, the M×N laser processing units 3 of the equipment are used to synchronously carry out high-precision SLM forming on the M×N sub-areas 7 corresponding to the current positions of the M×N laser processing units 3; wherein, when each laser processing unit 3 forms the sub-area 7 it is responsible for, the P processing modules contained in the laser processing unit 3 simultaneously form the corresponding high-precision forming partition 8 in the sub-area 7; wherein, the i-th processing module forms the i-th, P+i-th, ..., (X-1)×P+i-th high-precision forming partitions 8 in sequence;

[0071] S7, according to the kilowatt-class high-power laser scanning trajectory generated in step S4, the M×N sub-areas 7 corresponding to the current positions of the M×N laser processing units 3 are synchronously subjected to high-efficiency SLM forming; wherein, when each laser processing unit 3 forms the sub-area 7 it is responsible for, the P processing modules contained in the laser processing unit 3 simultaneously form the corresponding high-efficiency forming partition 9 in the sub-area 7; wherein, the i-th processing module forms the i-th, P+i-th, ..., (Y-1)×P+i-th high-efficiency forming partitions 9 in sequence;

[0072] S8, moving the M laser processing unit assemblies of the equipment to the corresponding sub-region columns that have not yet been formed, and completing the forming of these sub-region columns with reference to steps S7 and S8, thereby completing the forming of the first metal powder layer 1;

[0073] S9. Referring to steps S5, S6, S7 and S8, the laying and SLM forming of the subsequent metal powder layer 1 are completed in sequence, thereby completing the SLM forming of the large-sized metal parts.

[0074] As an optimization scheme, in order to further improve the forming efficiency, in steps S6 and S7, after the i-th processing module completes the forming of the i-th, P+i-th, ..., (X-1)×P+i-th high-precision forming partitions 8 in sequence, without waiting for other processing modules to complete the forming of the corresponding high-precision forming partitions 8, the processing module immediately performs the forming of the i-th, P+i-th, ..., (Y-1)×P+i-th high-efficiency forming partitions 9 in sequence.

[0075] As an optimization scheme, in order to further improve the forming accuracy of the high-precision forming area; in step S6, by controlling the laser mode and laser output power of the optical fiber laser with adjustable spot mode, as well as the focusing parameters of the dynamic focusing galvanometer 6, the laser power of the hundred-watt low-power laser 4 used in the forming of the high-precision forming partition 8 is ≤500W, the spot mode is Gaussian mode, and the spot diameter on the surface of the metal powder layer is ≤100μm.

[0076] As an optimization scheme, in order to further improve the forming efficiency of the high-efficiency forming area and improve the mechanical properties; in step S7, by controlling the laser mode and laser output power of the optical fiber laser with adjustable spot mode, and the focusing parameters of the dynamic focusing galvanometer 6, the laser power of the kilowatt-class high-power laser 4 used in the forming of the high-efficiency forming partition 9 is ≥2kW, the spot mode is annular mode or Gaussian / annular combination mode, and the spot diameter on the surface of the metal powder layer is ≥200μm.

[0077] To further improve the forming quality, in steps S4 and S5, the value of the positive integer X is 2≤X≤5, and the value of the positive integer Y is 2≤Y≤5; the shapes of the high-precision forming partition 8 and the high-efficiency forming partition 9 are both rectangular.

[0078] In order to further improve the forming efficiency and give full play to the role of each processing module, in the high-precision forming of steps S4 and S6, the X×P high-precision forming partitions 8 of each sub-area 7 are sorted according to the total length of their respective hundred-watt low-power laser scanning trajectories; specifically, the higher the high-precision forming partition with the larger total length of the hundred-watt low-power laser scanning trajectory is, the higher the ranking is when numbering; for example, the high-precision forming partition with the largest total length of the hundred-watt low-power laser scanning trajectory is counted as the first high-precision forming partition.

[0079] Similarly, in order to further improve the forming efficiency and give full play to the role of each processing module, in the high-efficiency forming of steps S4 and S7, the Y×P high-efficiency forming partitions 9 of each sub-area 7 are sorted according to the total length of their respective kilowatt-level high-power laser scanning trajectories; specifically, the higher the high-efficiency forming partition with the larger total length of the kilowatt-level high-power laser scanning trajectory, the higher the ranking when numbering; for example, the high-efficiency forming partition with the largest total length of the kilowatt-level high-power laser scanning trajectory is counted as the first high-efficiency forming partition.

[0080] The following is a detailed description with reference to specific embodiments:

[0081] Example 1

[0082] This embodiment provides a large-format, high-efficiency, high-precision SLM forming device, such as Figure 7As shown, it includes a forming cylinder and a laser processing unit assembly. The forming cylinder is used to lay the metal powder layer 1 layer by layer. The width and length of the metal powder layer 1 are 1500mm and 2000mm respectively. The laser processing unit assembly is located above the metal powder layer 1 and includes 5 laser processing units 3 arranged along the width direction of the metal powder layer 1. The forming width 2 of these laser processing units 3 is 300mm (in the width direction of the metal powder layer) × 210mm (in the length direction of the metal powder layer). They are also arranged along the width direction of the metal powder layer 1 and are assembled with each other, so that the effective forming width of the laser processing unit assembly covers the metal powder layer along the width direction of the metal powder layer 1. On this basis, the laser processing unit assembly can reciprocate along the length direction of the metal powder layer 1, so that the SLM forming of the entire metal powder layer 1 can be completed in the form of sub-stations.

[0083] like Figure 8 As shown, each laser processing unit 3 includes four processing modules. Each processing module includes a collimator 5 and a dynamic focusing galvanometer 6. The collimator 5 is connected to the fiber head of a spot mode adjustable fiber laser with a maximum laser output power of 6 kW through a QBH standard interface, collimates and expands the laser beam 4 output by the laser, and inputs the collimated and expanded laser beam 4 to the dynamic focusing galvanometer 6. The dynamic focusing galvanometer 6 is used to drive the collimated and expanded laser beam 4 to selectively melt the metal powder layer 1 according to a preset scanning trajectory, and is used to dynamically adjust the spot diameter of the laser beam 4 on the surface of the metal powder layer 1.

[0084] like Figure 8 As shown, the four processing modules of the laser processing unit 3 are arranged in two rows along the width direction of the metal powder layer 1, and the two rows of processing modules are symmetrically arranged.

[0085] like Figure 7 , 8 As shown, the envelope size K of the four processing modules along the width direction of the metal powder layer 1 is set to 290 mm, which is smaller than the envelope size L of the forming width 2 of the laser processing unit 3 along the width direction of the metal powder layer 1, which is 300 mm, so as to avoid position interference of adjacent laser processing units 3.

[0086] The technical effects achieved through the above settings are as follows Figure 5 As shown, specifically, by utilizing the characteristic that the scanning field 10 of the dynamic focusing galvanometer 6 is relatively large (much larger than the projection area of ​​the dynamic focusing galvanometer 6 on the surface of the metal powder layer 1), the four dynamic focusing galvanometers 6 arranged in two rows have a relatively large scanning field overlapping area 11, and a forming format 2 is provided in the scanning field overlapping area 11, so that the laser processing unit 3 can simultaneously use four groups of kilowatt-level high-power / hundred-watt-level low-power lasers 4 for forming in its forming format 2.

[0087] Based on the above large-format, high-efficiency, and high-precision SLM equipment, this embodiment proposes a method for SLM forming of large-size metal parts, including the following steps:

[0088] S1. Divide the three-dimensional digital model of the metal part into two parts and perform layered slicing processing respectively: one is the high-precision forming part with complex structure and high forming accuracy requirements, and the other is the high-efficiency forming part with relatively simple structure and relatively low forming accuracy requirements;

[0089] S2. Divide the metal powder layer 1 into a sub-region array including 5×10 (i.e., 50) sub-regions 7; wherein the sub-region array has a total of 5 rows along the width direction of the metal powder layer 1 and a total of 10 columns along the length direction of the metal powder layer 1; the size of each sub-region 7 along the width direction of the metal powder layer 1 is 300 mm, which is equal to the envelope size of 300 mm of the forming width 2 of the laser processing unit 3 along the width direction of the metal powder layer 1; the size of each sub-region 7 along the length direction of the metal powder layer 1 is 200 mm, which is smaller than the envelope size of 210 mm of the forming width 2 of the laser processing unit 3 along the length direction of the metal powder layer 1;

[0090] S3, allocating a laser processing unit 3 for SLM forming to each sub-region 7: Specifically, the laser processing unit assembly is responsible for the forming of 10 columns of sub-regions 7 in sequence; the five sub-regions 7 contained in each column of the sub-region array correspond one-to-one to the five laser processing units 3 contained in the laser processing unit assembly, and the corresponding one laser processing unit 3 is responsible for the forming;

[0091] S4. Plan the scanning trajectory of the low-power laser of the hundred-watt level and the high-power laser of the kilowatt level:

[0092] The 100-watt low-power laser scanning trajectory is planned in the following manner: Based on the division scheme and layered slicing data of the high-precision forming part of the three-dimensional digital model of the metal part, as well as the sub-area 7 division scheme of the metal powder layer and the laser processing unit 3 allocation scheme, a 100-watt low-power laser scanning trajectory is planned for each sub-area 7:

[0093] Specifically, Fig. 9As shown in (a), first, each sub-area 7 is equally divided into 2×4 (i.e., 8) rectangular high-precision forming partitions 8; these high-precision forming partitions 8 are sorted according to the total length of their respective hundred-watt-level low-power laser scanning tracks. Specifically, the high-precision forming partition 8 with a larger total length of the hundred-watt-level low-power laser scanning track is ranked higher in the numbering; for example, the high-precision forming partition 8 with the largest total length of the hundred-watt-level low-power laser scanning track is counted as the first high-precision forming partition (i.e., A1 high-precision forming partition), and the high-precision forming partition 8 with the smallest total length of the hundred-watt-level low-power laser scanning track is counted as the eighth high-precision forming partition (i.e., A8 high-precision forming partition);

[0094] Then, the first high-precision forming partition 8 (i.e., A1) and the fifth high-precision forming partition 8 (i.e., A5) of each sub-region 7 are allocated to the first processing module of the corresponding laser processing unit 3 for forming; the second high-precision forming partition 8 (i.e., A2) and the sixth high-precision forming partition 8 (i.e., A6) of each sub-region 7 are allocated to the second processing module of the corresponding laser processing unit 3 for forming; the third high-precision forming partition 8 (i.e., A3) and the seventh high-precision forming partition 8 (i.e., A7) of each sub-region 7 are allocated to the third processing module of the corresponding laser processing unit 3 for forming; the fourth high-precision forming partition 8 (i.e., A4) and the eighth high-precision forming partition 8 (i.e., A8) of each sub-region 7 are allocated to the fourth processing module of the corresponding laser processing unit 3 for forming;

[0095] Further, based on the layered slice data of the high-precision forming part of the three-dimensional digital model of the metal part and the position distribution of the high-precision forming partition 8 of each sub-area 7, a low-power laser scanning trajectory of a processing module corresponding to each high-precision forming partition 8 is generated at a hundred-watt level;

[0096] The kilowatt-class high-power laser scanning trajectory is planned in the following manner: Based on the division scheme and layered slicing data of the high-efficiency forming part of the three-dimensional digital model of the metal part, as well as the sub-area 7 division scheme of the metal powder layer and the laser processing unit 3 allocation scheme, a kilowatt-class high-power laser scanning trajectory is planned for each sub-area 7:

[0097] Specifically, Fig. 9As shown in (b), first, each sub-area 7 is equally divided into 1×4 (i.e., 4) rectangular high-efficiency forming partitions 9; these high-efficiency forming partitions 9 are sorted according to the total length of their respective kilowatt-level high-power laser scanning tracks. Specifically, the high-efficiency forming partition 9 with a larger total length of the kilowatt-level high-power laser scanning track is ranked higher in numbering; for example, the high-efficiency forming partition 9 with the largest total length of the kilowatt-level high-power laser scanning track is counted as the first high-efficiency forming partition (i.e., high-efficiency forming partition No. B1), and the high-efficiency forming partition 9 with the smallest total length of the kilowatt-level high-power laser scanning track is counted as the fourth high-precision forming partition (i.e., high-efficiency forming partition No. B4);

[0098] Then, the first high-efficiency forming partition 9 (i.e., B1) of each sub-region 7 is allocated to the first processing module of the corresponding laser processing unit 3 for forming; the second high-efficiency forming partition 9 (i.e., B2) of each sub-region 7 is allocated to the second processing module of the corresponding laser processing unit 3 for forming; the third high-efficiency forming partition 9 (i.e., B3) of each sub-region 7 is allocated to the third processing module of the corresponding laser processing unit 3 for forming; the fourth high-efficiency forming partition 9 (i.e., B4) of each sub-region 7 is allocated to the fourth processing module of the corresponding laser processing unit 3 for forming;

[0099] Further, based on the layered slice data of the high-efficiency forming part of the three-dimensional digital model of the metal part and the position distribution of the high-efficiency forming partition 9 of each sub-area 7, a kilowatt-level high-power laser scanning trajectory of the processing module corresponding to each high-efficiency forming partition 9 is generated;

[0100] S5, laying a first metal powder layer 1 in the forming cylinder, and moving the laser processing unit assembly of the equipment to above the first column sub-area 7;

[0101] S6, according to the 100-watt low-power laser scanning trajectory of each processing module generated in step S4, using all five laser processing units 3 of the equipment, synchronously carry out high-precision SLM forming on the five sub-areas 7 corresponding to the current positions of the five laser processing units 3;

[0102] When each laser processing unit 3 forms the sub-area 7 it is responsible for, the four processing modules contained in the laser processing unit 3 simultaneously form the corresponding high-precision forming partitions 8 in the sub-area 7; the first processing module forms the high-precision forming partitions 8 A1 and A5 in sequence; the second processing module forms the high-precision forming partitions 8 A2 and A6 in sequence; the third processing module forms the high-precision forming partitions 8 A3 and A7 in sequence; the fourth processing module forms the high-precision forming partitions 8 A4 and A8 in sequence;

[0103] In this step, by controlling the laser mode and laser output power of the optical fiber laser with adjustable spot mode, and the focusing parameters of the dynamic focusing galvanometer 6, the laser power of the 100-watt low-power laser 4 used in the high-precision forming partition 8 is set to 300W, the spot mode is set to Gaussian mode, and the spot diameter on the surface of the metal powder layer is set to 80μm;

[0104] S7, according to the kilowatt-class high-power laser scanning trajectory generated in step S4, high-efficiency SLM forming is synchronously performed on the five sub-areas 7 corresponding to the current positions of the five laser processing units 3;

[0105] When each laser processing unit 3 forms the sub-area 7 it is responsible for, the four processing modules contained in the laser processing unit 3 simultaneously form the corresponding high-efficiency forming partitions in the sub-area 7; wherein the first processing module forms the high-efficiency forming partition No. B1; the second processing module forms the high-efficiency forming partition No. B2 9; the third processing module forms the high-efficiency forming partition No. B3; and the fourth processing module forms the high-efficiency forming partition No. B4;

[0106] In this step, by controlling the laser mode and laser output power of the spot mode adjustable fiber laser and the focusing parameters of the dynamic focusing galvanometer 6, the laser power of the kilowatt-class high-power laser 4 used in the forming of the high-efficiency forming partition 9 is set to 3 kW, the spot mode is a Gaussian / annular combination mode, and the spot diameter on the surface of the metal powder layer is 500 μm.

[0107] S8, moving the laser processing unit assembly of the equipment to the upper part of the sub-region columns that have not been formed in sequence, and completing the forming of these sub-region columns with reference to steps S6 and S7, thereby completing the forming of the first metal powder layer 1;

[0108] S9. Referring to steps S5, S6, S7 and S8, the subsequent metal powder layer laying and SLM forming are completed in sequence, thereby completing the SLM forming of large-size metal parts.

[0109] Example 2

[0110] This embodiment provides a large-format, high-efficiency, high-precision SLM forming device, such as Fig.10 As shown, it includes a forming cylinder and two laser processing unit components. The forming cylinder is used to lay a metal powder layer 1 layer by layer, the width and length of the metal powder layer 1 are 900 mm and 1500 mm respectively, and the two laser processing unit components are both located above the metal powder layer 1.

[0111] Each laser processing unit assembly includes three laser processing units 3 arranged in an array along the width direction of the metal powder layer 1. The forming width 2 of these laser processing units 3 is 300 mm (in the width direction of the metal powder layer) × 500 mm (in the length direction of the metal powder layer). They are also arranged in an array along the width direction of the metal powder layer 1 and are assembled with each other, so that the effective forming width of the corresponding laser processing unit assembly covers the metal powder layer along the width direction of the metal powder layer 1. On this basis, each laser processing unit assembly can reciprocate along the length direction of the metal powder layer 1, so that the SLM forming of the entire metal powder layer 1 can be completed in the form of divided workstations.

[0112] like Fig.11 As shown, each laser processing unit 3 includes two processing modules. Each processing module includes a collimator 5 and a dynamic focusing galvanometer 6. The collimator 5 is connected to the fiber head of a spot mode adjustable fiber laser with a maximum output power of 4kW through a QBH standard interface, collimates and expands the laser beam 4 output by the laser, and inputs the collimated and expanded laser beam 4 to the dynamic focusing galvanometer 6. The dynamic focusing galvanometer 6 is used to drive the collimated and expanded laser beam 4 to selectively melt the metal powder layer 1 according to a preset scanning trajectory, and is used to dynamically adjust the spot diameter of the laser beam 4 on the surface of the metal powder layer 1. The spot mode adjustable fiber laser adopts a standardized product, has a real-time adjustment function of the laser beam mode, and can realize the alternating output of Gaussian mode laser beam, annular mode laser beam, and Gaussian / annular combination mode laser beam.

[0113] like Fig.11 As shown, the two processing modules of the laser processing unit 3 are arranged in a row along the width direction of the metal powder layer. Fig.10 , 11 As shown, the envelope size K of the two processing modules along the width direction of the metal powder layer is set to 295 mm, which is smaller than the envelope size L of the forming width 2 of the laser processing unit 3 along the width direction of the metal powder layer 1, which is 300 mm, so as to avoid position interference between adjacent laser processing units 3 in the same laser processing unit assembly.

[0114] The technical effects achieved through the above settings are as follows Figure 5 As shown, specifically, by utilizing the characteristic that the scanning field 10 of the dynamic focusing galvanometer 6 is relatively large (much larger than the projection area of ​​the dynamic focusing galvanometer 6 on the surface of the metal powder layer 1), two dynamic focusing galvanometers 6 arranged in a row have a relatively large scanning field overlapping area 11, and a forming format 2 is provided in the scanning field overlapping area 11, so that the laser processing unit 3 can simultaneously use two groups of kilowatt-level high-power / hundred-watt-level low-power lasers 4 for forming within its forming format 2.

[0115] Based on the above large-format, high-efficiency, and high-precision SLM equipment, this embodiment proposes a method for SLM forming of large-size metal parts, including the following steps:

[0116] S1. Divide the three-dimensional digital model of the metal part into two parts and perform layered slicing processing respectively: one is the high-precision forming part with complex structure and high forming accuracy requirements, and the other is the high-efficiency forming part with relatively simple structure and relatively low forming accuracy requirements;

[0117] S2. Divide the metal powder layer 1 into a sub-region array including 4×3 sub-regions 7; wherein the sub-region array has 3 rows along the width direction of the metal powder layer 1 and 4 columns along the length direction of the metal powder layer 1; the size of each sub-region 7 along the width direction of the metal powder layer 1 is 300 mm, which is equal to the envelope size of 300 mm of the forming width 2 of the laser processing unit 3 along the width direction of the metal powder layer 1; the size of each sub-region 7 along the length direction of the metal powder layer 1 is 375 mm, which is smaller than the envelope size of 500 mm of the forming width 2 of the laser processing unit 3 along the length direction of the metal powder layer 1;

[0118] S3, allocating a laser processing unit 3 for SLM forming to each sub-region 7; specifically, the first laser processing unit assembly is responsible for the forming of the first and second columns of sub-regions 7 in turn, and the second laser processing unit assembly is responsible for the forming of the third and fourth columns of sub-regions 7 in turn; the three sub-regions 7 contained in each column of the sub-region array correspond one-to-one to the three laser processing units 3 contained in the corresponding laser processing unit assembly, and the corresponding one laser processing unit 3 is responsible for the forming;

[0119] S4. Plan the scanning trajectory of the low-power laser of the hundred-watt level and the high-power laser of the kilowatt level:

[0120] The 100-watt low-power laser scanning trajectory is planned in the following manner: based on the division scheme and layered slicing data of the high-precision forming part of the three-dimensional digital model of the metal part, as well as the sub-area 7 division scheme of the metal powder layer and the laser processing unit 3 allocation scheme, a 100-watt low-power laser scanning trajectory is planned for each sub-area 7;

[0121] Specifically, Fig.12As shown in (a), first, each sub-area 7 is equally divided into 3×2 (i.e., 6) rectangular high-precision forming partitions 8; these high-precision forming partitions 8 are sorted according to the total length of their respective hundred-watt-level low-power laser scanning tracks. Specifically, the high-precision forming partition 8 with a larger total length of the hundred-watt-level low-power laser scanning track is ranked higher in the numbering; for example, the high-precision forming partition 8 with the largest total length of the hundred-watt-level low-power laser scanning track is counted as the first high-precision forming partition (i.e., A1 high-precision forming partition), and the high-precision forming partition 8 with the smallest total length of the hundred-watt-level low-power laser scanning track is counted as the sixth high-precision forming partition (i.e., A6 high-precision forming partition);

[0122] Then, the first high-precision forming partition 8 (i.e., A1), the third high-precision forming partition 8 (i.e., A3), and the fifth high-precision forming partition 8 (i.e., A5) of each sub-area 7 are assigned to the first processing module of the corresponding laser processing unit 3 for forming; the second high-precision forming partition 8 (i.e., A2), the fourth high-precision forming partition 8 (i.e., A4), and the sixth high-precision forming partition 8 (i.e., A6) of each sub-area 7 are assigned to the second processing module of the corresponding laser processing unit 3 for forming; further, based on the layered slicing data of the high-precision forming part of the three-dimensional digital model of the metal part and the position distribution of the high-precision forming partition 8 of each sub-area 7, a low-power laser scanning trajectory of a hundred-watt level for the processing module corresponding to each high-precision forming partition 8 is generated;

[0123] The kilowatt-class high-power laser scanning trajectory is planned in the following manner: based on the division scheme and layered slicing data of the high-efficiency forming part of the three-dimensional digital model of the metal part, as well as the sub-region 7 division scheme of the metal powder layer and the laser processing unit 3 allocation scheme, a kilowatt-class high-power laser scanning trajectory is planned for each sub-region 7;

[0124] Specifically, Fig.12 As shown in (b), first, each sub-area 7 is equally divided into 3×2 (i.e., 6) rectangular high-efficiency forming partitions 9; these high-efficiency forming partitions 9 are sorted according to the total length of their respective kilowatt-level high-power laser scanning tracks. Specifically, the high-efficiency forming partition 9 with a larger total length of the kilowatt-level high-power laser scanning track is ranked higher in numbering; for example, the high-efficiency forming partition 9 with the largest total length of the kilowatt-level high-power laser scanning track is counted as the first high-efficiency forming partition (i.e., high-efficiency forming partition No. B1), and the high-efficiency forming partition 9 with the smallest total length of the kilowatt-level high-power laser scanning track is counted as the sixth high-precision forming partition (i.e., high-efficiency forming partition No. B6);

[0125] Then, the first high-efficiency forming partition 9 (i.e., B1), the third high-efficiency forming partition 9 (i.e., B3), and the fifth high-efficiency forming partition 9 (i.e., B5) of each sub-region 7 are assigned to the first processing module of the corresponding laser processing unit 3 for forming; the second high-efficiency forming partition 9 (i.e., B2), the fourth high-efficiency forming partition 9 (i.e., B4), and the sixth high-efficiency forming partition 9 (i.e., B6) of each sub-region 7 are assigned to the second processing module of the corresponding laser processing unit 3 for forming; further, according to the layered slicing data of the high-efficiency forming part of the three-dimensional digital model of the metal part and the position distribution of the high-efficiency forming partition 9 of each sub-region 7, the kilowatt-level high-power laser scanning trajectory of the processing module corresponding to each high-efficiency forming partition 9 is generated;

[0126] S5, laying the first metal powder layer 1 in the forming cylinder, and moving all two laser processing unit components of the equipment to the top of the corresponding first and third column sub-areas 7 respectively;

[0127] S6. According to the 100-watt low-power laser scanning trajectory of each processing module generated in step S4, all 2×3 (i.e. 6) laser processing units 3 of the equipment are used to synchronously carry out high-precision SLM forming on the 2×3 (i.e. 6) sub-areas 7 corresponding to the current positions of the 2×3 laser processing units 3; wherein, when each laser processing unit 3 forms the sub-area 7 it is responsible for, the two processing modules contained in the laser processing unit 3 simultaneously form the corresponding high-precision forming partition 8 in the sub-area 7; wherein, the first processing module forms high-precision forming partitions A1, A3, and A5 in sequence; and the second processing module forms high-precision forming partitions A2, A4, and A6 in sequence; in this step, by controlling the laser mode and laser output power of the optical fiber laser with adjustable spot mode, and the focusing parameters of the dynamic focusing galvanometer 6, the laser power of the 100-watt low-power laser 4 used in the forming of the high-precision forming partition 8 is 200W, the spot mode is Gaussian mode, and the spot diameter on the surface of the metal powder layer is 50μm.

[0128] S7, according to the kilowatt-class high-power laser scanning trajectory generated in step S4, the 2×3 (i.e., 6) sub-areas 7 corresponding to the current positions of the 2×3 (i.e., 6) laser processing units 3 are synchronously subjected to high-efficiency SLM forming; wherein, when each laser processing unit 3 forms the sub-area 7 for which it is responsible, the two processing modules contained in the laser processing unit 3 simultaneously form the corresponding high-efficiency forming partition 9 in the sub-area 7; wherein, the first processing module forms high-efficiency forming partitions B1, B3, and B5 in sequence; and the second processing module forms high-efficiency forming partitions B2, B4, and B6 in sequence; in this step, by controlling the laser mode and laser output power of the optical fiber laser with adjustable spot mode, and the focusing parameters of the dynamic focusing galvanometer 6, the laser power of the kilowatt-class high-power laser 4 used in the forming of the high-efficiency forming partition 9 is 2kW, the spot mode is an annular mode, and the spot diameter on the surface of the metal powder layer is 400μm;

[0129] S8, moving the two laser processing unit assemblies of the equipment to the corresponding second and fourth sub-region columns that have not yet been formed, and completing the forming of these sub-region columns with reference to steps S6 and S7, thereby completing the forming of the first metal powder layer 1;

[0130] S9. Referring to steps S5, S6, S7 and S8, the laying and SLM forming of the subsequent metal powder layer 1 are completed in sequence, thereby completing the SLM forming of the large-sized metal parts.

[0131] In order to further improve the forming efficiency, in steps S6 and S7, after a certain processing module of each laser processing unit 3 has first completed the forming of all the high-precision forming partitions 8 for which it is responsible, the processing module immediately performs the forming of the high-efficiency forming partition 9 for which it is responsible without waiting for other processing modules of the laser processing unit 3 to complete the forming of the corresponding high-precision forming partitions 8.

[0132] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A large-scale, high-efficiency, high-precision laser selective melting forming equipment, characterized by: It includes a forming cylinder and a laser processing unit assembly, wherein: The forming cylinder is used to lay metal powder layers layer by layer; The laser processing unit assembly is used for SLM forming of the metal powder layer, and is located above the forming cylinder. The number of the laser processing unit assemblies is M, M≥1, and they can reciprocate along the length direction of the metal powder layer. Each of the laser processing unit assemblies includes N laser processing units arrayed along the width direction of the metal powder layer, N≥2. The forming width of each laser processing unit is also arrayed along the width direction of the metal powder layer and spliced ​​with each other, so that the spliced ​​forming widths of each laser processing unit cover the metal powder layer along the width direction of the metal powder layer; Each of the laser processing units comprises P processing modules, P≥2, each of the processing modules is externally connected to an optical fiber laser with adjustable spot mode, and the optical fiber laser with adjustable spot mode can output a kilowatt-class high-power laser / a hundred-watt-class low-power laser; the scanning range of the kilowatt-class high-power laser / a hundred-watt-class low-power laser can cover the entire forming width of the corresponding laser processing unit; Each of the processing modules comprises a collimator and a dynamic focusing galvanometer; the collimator is connected to the optical fiber head of an adjustable spot mode optical fiber laser through a QBH standard interface, the maximum output laser power of the adjustable spot mode optical fiber laser is greater than or equal to 1KW, the collimator is used to collimate and expand the laser beam output by the adjustable spot mode optical fiber laser, and input the collimated and expanded laser beam to the dynamic focusing galvanometer; the dynamic focusing galvanometer is used to drive the collimated and expanded laser beam to selectively melt the metal powder layer according to a preset scanning trajectory, and is used to dynamically adjust the spot diameter of the laser beam on the surface of the metal powder layer; The envelope size K of the P processing modules along the width direction of the metal powder layer is less than or equal to the envelope size L of the forming width of the laser processing unit along the width direction of the metal powder layer.

2. The large-format, high-efficiency, high-precision laser selective melting forming equipment according to claim 1, characterized in that: The number M of the laser processing unit assemblies satisfies: 1≤M≤5; the number N of the laser processing units contained in each of the laser processing unit assemblies satisfies: 2≤N≤5.

3. The large-format, high-efficiency, high-precision laser selective melting forming equipment according to claim 1, characterized in that: The maximum output power of the optical fiber laser with adjustable spot mode is greater than or equal to 2 kW, and can realize the alternating output of Gaussian mode laser beam, annular mode laser beam, and Gaussian / annular combination mode laser beam.

4. A method for SLM forming of large-sized metal parts using the apparatus according to any one of claims 1 to 3, the method comprising the following steps: S1. Divide the three-dimensional digital model of the metal part into a high-precision forming part and a high-efficiency forming part, and perform layered slicing on the two parts respectively; S2. According to the number M of laser processing unit assemblies, the number N of laser processing units contained in each laser processing unit assembly, and the forming width, the metal powder layer is divided into a sub-region array including Q×N sub-regions, Q≥M+1; wherein, The sub-region array has N rows along the width direction of the metal powder layer and Q columns along the length direction of the metal powder layer; the size of each sub-region along the width direction of the metal powder layer is equal to the envelope size L of the forming width of the laser processing unit along the width direction of the metal powder layer; the size of each sub-region along the length direction of the metal powder layer is less than or equal to the envelope size of the forming width of the laser processing unit along the length direction of the metal powder layer; S3. Allocate a laser processing unit for SLM forming to each sub-region: each laser processing unit assembly is responsible for forming at least one column of sub-region arrays, and all laser processing unit assemblies are responsible for forming all Q columns of sub-region arrays; the N sub-regions contained in each column of sub-region arrays correspond one-to-one to the laser processing units of the corresponding laser processing unit assembly, that is, each sub-region is formed by a corresponding laser processing unit; S4. Plan the scanning trajectory of the low-power laser of the hundred-watt level and the high-power laser of the kilowatt level: The 100-watt low-power laser scanning trajectory is planned in the following manner: According to the division scheme and layered slicing data of the high-precision forming part of the three-dimensional digital model of the metal part, as well as the sub-area division scheme and laser processing unit allocation scheme of the metal powder layer, the 100-watt low-power laser scanning trajectory is planned for each sub-area: First, each sub-region is equally divided into X×P high-precision forming partitions, where X is an integer greater than or equal to 1; then, the i-th, P+i-th, …, (X-1)×P+i-th high-precision forming partitions of each sub-region, 1≤i≤P, are assigned to the i-th processing module of the corresponding laser processing unit for forming; Based on the layered slice data of the high-precision forming part of the three-dimensional digital model of the metal part and the position distribution of the high-precision forming partitions of each sub-area, a low-power laser scanning trajectory of a hundred-watt level for the processing module corresponding to each high-precision forming partition is generated; The kilowatt-class high-power laser scanning trajectory is planned in the following manner: based on the division scheme and layered slicing data of the high-efficiency forming part of the three-dimensional digital model of the metal part, as well as the sub-area division scheme and laser processing unit allocation scheme of the metal powder layer, a kilowatt-class high-power laser scanning trajectory is planned for each sub-area: First, each sub-region is equally divided into Y×P high-efficiency forming partitions, where Y is an integer greater than or equal to 1; then, the i-th, P+i-th, …, (Y-1)×P+i-th high-efficiency forming partitions of each sub-region are assigned to the i-th processing module of the corresponding laser processing unit for forming; Based on the hierarchical slice data of the high-efficiency forming part of the three-dimensional digital model of the metal part and the position distribution of the high-efficiency forming partitions of each sub-area, a kilowatt-level high-power laser scanning trajectory of the processing module corresponding to each high-efficiency forming partition is generated; S5, laying a first layer of metal powder in the forming cylinder, and moving the M laser processing unit components of the equipment to the top of a corresponding column of sub-area arrays; S6. According to the 100-watt low-power laser scanning trajectory of each processing module generated in step S4, the M×N laser processing units in the equipment are used to synchronously carry out high-precision SLM forming on the M×N sub-areas corresponding to the current positions of the M×N laser processing units; wherein, when each laser processing unit forms the sub-area it is responsible for, the P processing modules contained in the laser processing unit simultaneously form the corresponding high-precision forming partition in the sub-area; wherein, the i-th processing module forms the i-th, P+i-th, ..., (X-1)×P+i-th high-precision forming partitions in sequence; S7. According to the kilowatt-class high-power laser scanning trajectory generated in step S4, high-efficiency SLM forming is synchronously performed on the M×N sub-areas corresponding to the current positions of the M×N laser processing units; wherein, when each laser processing unit forms the sub-area it is responsible for, the P processing modules contained in the laser processing unit simultaneously form the corresponding high-efficiency forming partition in the sub-area; wherein, the i-th processing module forms the i-th, P+i-th, ..., (Y-1)×P+i-th high-efficiency forming partitions in sequence; S8, respectively moving the M laser processing unit assemblies of the equipment to the corresponding sub-region columns that have not yet been formed, and completing the forming of these sub-region columns with reference to steps S6 and S7, thereby completing the forming of the first metal powder layer; S9. Referring to steps S5, S6, S7 and S8, the subsequent metal powder layer laying and SLM forming are completed in sequence, thereby completing the SLM forming of large-size metal parts.

5. The method for SLM forming of large-size metal parts according to claim 4, characterized in that: In steps S6 and S7, after the i-th processing module completes the forming of the i-th, P+i-th,…, and (X-1)×P+i-th high-precision forming partitions in sequence, it does not wait for other processing modules to complete the forming of the corresponding high-precision forming partitions, and the processing module immediately performs the forming of the i-th, P+i-th,…, and (Y-1)×P+i-th high-efficiency forming partitions in sequence.

6. The method for SLM forming of large-size metal parts according to claim 4, characterized in that: In step S6, by controlling the laser mode and laser output power of the optical fiber laser with adjustable spot mode and the focusing parameters of the dynamic focusing galvanometer, the laser power of the hundred-watt low-power laser used in high-precision forming partition forming is made ≤500W, the spot mode is Gaussian mode, and the spot diameter on the surface of the metal powder layer is ≤100μm.

7. The method for SLM forming of large-size metal parts according to claim 4, characterized in that: In step S7, by controlling the laser mode and laser output power of the spot mode adjustable fiber laser and the focusing parameters of the dynamic focusing galvanometer, the laser power of the kilowatt-class high-power laser used in high-efficiency forming partition forming is ≥2kW, the spot mode is an annular mode or a Gaussian / annular combination mode, and the spot diameter on the surface of the metal powder layer is ≥200μm.

8. The method for SLM forming of large-size metal parts according to claim 4, characterized in that: In step S4, the value of X is 5≥X≥2, and the value of Y is 5≥X≥2; the shapes of the high-precision forming partition and the high-efficiency forming partition are both rectangular.

9. The method for SLM forming of large-size metal parts according to claim 4, characterized in that: In the high-precision forming of steps S4 and S6, the X×P high-precision forming partitions of each sub-area are sorted according to the total lengths of their respective hundred-watt-class low-power laser scanning trajectories; specifically, the higher the total length of the hundred-watt-class low-power laser scanning trajectory is, the higher the ranking is when numbering; in the high-efficiency forming of steps S4 and S7, the Y×P high-efficiency forming partitions of each sub-area are sorted according to the total lengths of their respective kilowatt-class high-power laser scanning trajectories; specifically, the higher the total length of the kilowatt-class high-power laser scanning trajectory is, the higher the ranking is when numbering.

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