Laser additive and subtractive composite manufacturing equipment and method with multiple milling processes in parallel

Abstract

The present invention discloses a laser additive and subtractive composite manufacturing device and method with multiple milling processes in parallel, belonging to the field of advanced manufacturing technology. The device includes a processing plane, a scanning galvanometer assembly, and a milling head assembly. The processing plane is used to lay metal powder layers layer by layer; the scanning galvanometer assembly is used for SLM forming of the metal powder layer and is located above the processing plane, including multiple scanning galvanometer units; the milling head assembly is used for milling processing of the metal powder layer after SLM forming, including multiple milling heads arrayed along the width direction of the metal powder layer, the effective processing widths of the multiple milling heads are spliced ​​together and cover the entire processing plane, and each of the milling heads can reciprocate along the width direction, length direction, and thickness direction of the metal powder layer. The device provided by the present invention can synchronously perform mechanical milling processing on the forming layer of the laser selective melting of the metal part, so that the forming speed of the laser additive and subtractive composite manufacturing technology is significantly improved compared with the existing level.

Description

Technical Field

[0001] The present invention belongs to the field of advanced manufacturing technology, and more specifically, relates to a laser additive and subtractive composite manufacturing device and method with multiple milling processes performed in parallel. Background Art

[0002] Selective Laser Melting (SLM) technology is a 3D printing technology for metal parts that has developed rapidly in recent years. Based on the slicing data of the three-dimensional digital model of the metal part, it uses a scanning galvanometer to guide a high-energy density laser beam to selectively scan the metal powder layer. The metal powder scanned by the laser is rapidly melted and quickly solidified into a forming layer. Through the repeated implementation of "metal powder layer pre-laying + laser selective scanning melting", high-performance forming of almost any complex metal part can be achieved without the aid of molds and special tooling.

[0003] Thanks to its powerful manufacturing capabilities, SLM technology has shown great application prospects in the manufacture of high-end equipment in the fields of aerospace, military, energy, rail transportation, and shipbuilding. However, due to the inevitable powder splashing and violent flow of the molten metal during the laser beam scanning and melting of the metal powder layer, the surface roughness and dimensional accuracy of metal parts formed using SLM technology generally do not meet the machining level, and cannot meet the needs of direct use. Subsequent machining is required before they can be put into use. Because metal parts formed using SLM technology often have very complex external structures, subsequent machining of these parts is relatively difficult, resulting in a significant increase in the cost of part manufacturing.

[0004] In response to the above bottleneck problems, research institutions at home and abroad have proposed a laser additive and subtractive composite manufacturing technology that integrates the SLM process with the mechanical milling process. The basic principle is to integrate the milling head into the SLM equipment. In the manufacturing process of metal parts, each time the SLM forming of one or several layers of metal powder is completed, the milling head is used to perform mechanical milling on the forming layer according to the precision requirements of the part. Compared with the complex three-dimensional metal parts after forming, the milling difficulty of the forming layer that is approximately two-dimensional in shape is greatly reduced. In this way, through the alternation of the SLM process and the mechanical milling process, the laser additive and subtractive composite manufacturing technology can directly obtain complex metal parts with surface roughness and dimensional accuracy that meet the standards without the need for subsequent machining of the metal parts.

[0005] It's worth noting that compared to other mainstream metal part 3D printing technologies (such as arc fuse forming, electron beam selective melting, and laser fuse forming), SLM technology boasts a relatively slow build speed. Laser additive and subtractive manufacturing, due to the inclusion of a mechanical milling process in the SLM build process, further reduces its build speed, becoming a significant obstacle to large-scale application. Whether laser additive and subtractive manufacturing can be improved in speed will largely determine its future.

[0006] To sum up, in order to address the problem of low forming speed of the existing laser additive and subtractive composite manufacturing technology, a new laser additive and subtractive composite manufacturing equipment and method with significantly improved forming speed compared with the existing level was invented, which is of great significance to the application and promotion of laser additive and subtractive composite manufacturing technology. Summary of the Invention

[0007] In view of the defects of the prior art, the purpose of the present invention is to provide a laser additive and subtractive composite manufacturing device and method with multiple sets of milling processes in parallel, aiming to solve the problem of low forming speed of laser additive and subtractive composite manufacturing technology.

[0008] To achieve the above-mentioned purpose, the present invention provides a laser additive and subtractive composite manufacturing device with multiple milling processes in parallel, comprising a processing plane, a scanning galvanometer assembly and a milling head assembly;

[0009] The processing plane is used to lay metal powder layers layer by layer;

[0010] The scanning galvanometer assembly is used for SLM forming of the metal powder layer and is located above the processing plane, and includes a plurality of scanning galvanometer units. The effective forming widths of the plurality of scanning galvanometer units can be combined to cover the entire processing plane.

[0011] The milling head assembly is used for milling processing after SLM forming of the metal powder layer and is located between the scanning galvanometer assembly and the processing plane. It includes multiple milling heads arrayed along the width direction of the metal powder layer. The effective processing surfaces of the multiple milling heads are spliced ​​together and cover the entire processing plane, and each of the milling heads can reciprocate along the width direction, length direction and thickness direction of the metal powder layer.

[0012] Furthermore, the number of the scanning galvanometer units is M, and the scanning galvanometer units are fixed above the processing plane. The forming widths of the M scanning galvanometer units are spliced ​​together so that the effective forming width of the scanning galvanometer assembly covers the entire processing plane.

[0013] Furthermore, the scanning galvanometer units are movably installed above the processing plane and are arrayed in N rows along the width direction of the metal powder layer, each row containing M / N (M / N is an integer) scanning galvanometer units, the forming widths of the scanning galvanometer units in the same row are spliced ​​together, and each row of scanning galvanometer units can move back and forth along the length direction of the metal powder layer, so that the effective forming width of the scanning galvanometer assembly covers the entire processing plane.

[0014] Furthermore, the scanning galvanometer unit is externally connected to a kilowatt-class high-power fiber laser to perform SLM forming of the metal powder layer.

[0015] The present invention also provides a laser additive and subtractive composite manufacturing method with multiple milling processes in parallel, which is characterized by comprising the following steps:

[0016] S1. Slice the three-dimensional digital model of the metal part to obtain the contour data of each slice layer of the metal part;

[0017] S2. Laying the first metal powder layer on the processing plane;

[0018] S3. When M scanning galvanometer units are fixedly installed above the processing plane, each scanning galvanometer unit works simultaneously, and according to the contour data of the first slicing layer, the first metal powder layer is subjected to parallel and partitioned SLM forming as a whole to form the first formed layer; when M scanning galvanometer units are movably installed above the processing plane, each column of scanning galvanometer units needs to be moved above the metal powder layer, and according to the contour data of the first slicing layer, the portion of the metal powder layer located within the effective forming width of each column of scanning galvanometer units is subjected to parallel and partitioned SLM forming, and then each column of scanning galvanometer units is moved in turn to the metal powder layer that has not yet completed SLM forming, and gradually completes the SLM forming of the entire metal powder layer to form the first formed layer;

[0019] S4, determining whether the first forming layer needs to be milled. If so, multiple milling heads simultaneously mill the first forming layer to complete the processing; if not, proceeding to the next step;

[0020] S5. Referring to steps S2, S3 and S4, the subsequent metal powder layer laying, SLM forming and milling of the formed layer are repeated in sequence until the additive and subtractive composite manufacturing of the metal part is completed.

[0021] Furthermore, in step S3, the laser power output by the scanning galvanometer unit is greater than or equal to 2KW.

[0022] Furthermore, in step S4, a splicing line is provided between the processing surfaces of adjacent milling heads, and safety zones are symmetrically provided on both sides of the splicing line. The length dimension of the safety zone is the same as the length dimension of the processing surface, the width dimension of the processing surface is W, the width dimension of the safety zone is W0, and 0.3W≥W0≥0.1W is satisfied; when adjacent milling heads perform mechanical milling processing of the forming layer, the adjacent milling heads alternately complete the milling processing in their respective safety zones, and cannot perform processing in the safety zones at the same time.

[0023] In general, the above technical solutions conceived by the present invention have the following beneficial effects compared with the prior art:

[0024] (1) The milling head assembly of the present invention includes multiple milling heads, which divide the metal powder layer formed by SLM into multiple processing widths along the width direction, and can simultaneously carry out mechanical milling processing on these processing widths, greatly improving the forming speed of the milling process in the laser additive and subtractive composite manufacturing process, thereby significantly improving the forming speed of laser additive and subtractive composite manufacturing technology compared to the existing level, and providing a new method for short-cycle, low-cost, and large-scale manufacturing of metal parts;

[0025] (2) In the present invention, both the scanning galvanometer assembly and the milling head assembly can be moved above the metal powder layer, so that during the SLM forming process of the metal powder layer, the area of ​​the metal powder layer that has completed SLM forming can be mechanically milled in parallel by multiple milling heads, so that SLM forming and mechanical milling can be carried out simultaneously, shortening the overall processing time of the metal powder layer, thereby further improving the forming speed of laser additive and subtractive composite manufacturing.

[0026] (3) The present invention sets two safety zones symmetrically on both sides of the joint line of adjacent milling head processing widths and optimizes the size of the safety zones and the milling processing sequence. Under the premise of ensuring the milling processing efficiency, the position interference of the milling heads with adjacent processing widths is avoided, thereby further improving the process stability and product quality of laser additive and subtractive composite manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The present invention provides a method for arranging a scanning galvanometer component and a milling head component in a laser additive and subtractive composite manufacturing device with multiple milling processes in parallel.

[0028] Figure 2 This is another arrangement of the scanning galvanometer assembly and the milling head assembly of the laser additive and subtractive composite manufacturing equipment with multiple milling processes in parallel provided by a specific embodiment of the present invention;

[0029] Figure 3Schematic diagram of a laser additive and subtractive composite manufacturing method with multiple milling processes in parallel provided by a specific embodiment of the present invention;

[0030] Figure 4 Schematic diagram of another laser additive and subtractive composite manufacturing method with multiple milling processes in parallel provided by a specific embodiment of the present invention;

[0031] Figure 5 This is a schematic diagram of a method provided by the present invention in which two safety zones are symmetrically arranged on both sides of a joining line of adjacent milling head processing widths;

[0032] Figure 6 This is the arrangement of the scanning galvanometer assembly and the milling head assembly of a laser additive and subtractive composite manufacturing device with multiple milling processes in parallel provided in Example 1;

[0033] Figure 7 Schematic diagram of a laser additive and subtractive composite manufacturing method with multiple milling processes in parallel provided in Example 1;

[0034] Figure 8 This is the arrangement of the scanning galvanometer assembly and the milling head assembly of a laser additive and subtractive composite manufacturing device with multiple milling processes in parallel, as provided in Example 2;

[0035] Figure 9 This is a schematic diagram of a laser additive and subtractive composite manufacturing method with multiple milling processes in parallel provided in Example 2.

[0036] The structures corresponding to the numbered marks in the accompanying drawings are: 1-processing plane, 2-scanning galvanometer unit, 3-milling head, 4-processing width, 5-joining line, 6-safety zone. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to 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.

[0038] See Figures 1 to 2 The present invention provides a laser additive manufacturing device with multiple milling processes in parallel, which includes a scanning galvanometer assembly, a milling head assembly, and a processing plane 1; wherein the processing plane 1 is used to lay metal powder layers layer by layer; the scanning galvanometer assembly includes M scanning galvanometer units 2 (M≥2) for SLM forming of metal powder layers, and there are two ways to install them, respectively as follows:

[0039] The first fixed installation method is as follows Figure 1As shown, at this time, these scanning galvanometer units 2 are fixedly installed above the processing plane 1, and their forming widths are spliced ​​together so that the effective forming width of the scanning galvanometer assembly covers the entire processing plane 1. This fixing method can be used when the processed parts are small.

[0040] The second installation method is as follows Figure 2 As shown, at this time, these scanning galvanometer units 2 are movably installed above the processing plane 1, and are arranged into N columns (N≥1) along the width direction of the metal powder layer, and each column contains M / N (M / N is an integer) scanning galvanometer units 2. The forming widths of the scanning galvanometer units 2 in the same column are spliced ​​together, and each column of scanning galvanometer units can move back and forth along the length direction of the metal powder layer, so that the effective forming width of the scanning galvanometer assembly covers the entire processing plane 1; since the scanning galvanometer units 2 are arranged in columns and can move back and forth, it is suitable for processing larger parts, and the equipment cost can be reduced by reducing the number of galvanometer units 2; for the second arrangement of the scanning galvanometer units, the motion guide mechanism of each column of the scanning galvanometer units is preferably a linear guide rail, which can compress the equipment volume under the premise of ensuring motion accuracy.

[0041] In order to increase the forming speed of the SLM process as much as possible, the laser externally connected to the scanning galvanometer unit 2 is preferably a kilowatt-class high-power fiber laser.

[0042] like Figure 1 、 2 As shown, the milling head assembly is used for milling processing after SLM forming of the metal powder layer and is located between the scanning galvanometer assembly and the processing plane 1. It includes a plurality of milling heads arrayed along the width direction of the metal powder layer. The number of milling heads 3 is P (P≥2). The effective processing widths of each milling head 3 are spliced ​​together and cover the entire processing plane 1. Mechanical milling processing of these processing widths can be carried out simultaneously, which greatly improves the forming speed of the milling process in the laser additive and subtractive composite manufacturing process, thereby significantly improving the forming speed of the laser additive and subtractive composite manufacturing technology compared to the existing level, and provides a new method for short-cycle, low-cost, large-scale manufacturing of metal parts.

[0043] To achieve processing of the metal powder layer in all directions, these milling heads 3 can independently reciprocate along the width, length, and thickness of the metal powder layer. The movement mechanism of these milling heads 3 is preferably a robotic arm or a multi-axis module, which can reduce the size of the equipment while ensuring movement accuracy.

[0044] like Figure 3 、 4 As shown, the processing width 4 of each milling head 3 is overlapped with each other along the width direction of the metal powder layer, so that the effective processing width of the milling head assembly covers the entire processing plane 1.

[0045] Based on the above laser additive and subtractive composite manufacturing equipment with multiple milling processes in parallel, the present invention proposes a laser additive and subtractive composite manufacturing method for metal parts, comprising the following steps:

[0046] S1. Slice the three-dimensional digital model of the metal part to obtain the contour data of each slice layer of the metal part;

[0047] S2. Laying the first metal powder layer on the processing plane;

[0048] S3. When M scanning galvanometer units are fixedly installed above the processing plane, each scanning galvanometer unit works simultaneously, and according to the contour data of the first slicing layer, the first metal powder layer is subjected to parallel and partitioned SLM forming as a whole to form the first formed layer; when M scanning galvanometer units are movably installed above the processing plane, each column of scanning galvanometer units needs to be moved above the metal powder layer, and according to the contour data of the first slicing layer, the portion of the metal powder layer located within the effective forming width of each column of scanning galvanometer units is subjected to parallel and partitioned SLM forming, and then each column of scanning galvanometer units is moved in turn to the metal powder layer that has not yet completed SLM forming, and gradually completes the SLM forming of the entire metal powder layer to form the first formed layer;

[0049] S4, determining whether the first forming layer needs to be milled. If so, multiple milling heads simultaneously mill the first forming layer to complete the processing; if not, proceeding to the next step;

[0050] S5. Referring to steps S2, S3 and S4, the subsequent metal powder layer laying, SLM forming and milling of the formed layer are repeated in sequence until the additive and subtractive composite manufacturing of the metal part is completed.

[0051] In step S4, in order to avoid position interference between two milling heads 3 with adjacent processing widths, two safety zones 6 can be symmetrically set on both sides of the joint line 5 of the processing widths 4 of the two milling heads 3, such as Figure 5 As shown, their sizes and milling sequence are set as follows:

[0052] (1) The dimensions of the two safety zones 6 along the length direction of the metal powder layer are the same as the processing width 4;

[0053] (2) The dimension W0 of the two safety zones 6 along the width direction of the metal powder layer and the dimension W of the processing width 4 along the width direction of the metal powder layer satisfy the relationship: 0.3W ≥ W0 ≥ 0.1W;

[0054] (3) During the mechanical milling process of the forming layer, the mechanical milling of another safety zone 6 can be carried out only after the mechanical milling of one safety zone 6 is completed, that is, the adjacent milling heads complete the processing of the safety zones 6 alternately.

[0055] The present invention is described in detail below with reference to specific embodiments:

[0056] Example 1

[0057] like Figure 6 As shown, this embodiment provides a laser additive and subtractive composite manufacturing equipment with multiple milling processes in parallel, including a scanning galvanometer assembly, a milling head assembly and a processing plane 1; wherein, the processing plane 1 is used to lay metal powder layers layer by layer. In this embodiment, the width and length of the metal powder layer are both 1200 mm; the scanning galvanometer assembly includes 9 scanning galvanometer units 2, which are fixedly installed above the processing plane 1 in the form of a "3×3 array", and the forming width of each scanning galvanometer unit 2 is 400 mm×400 mm. These forming widths are spliced ​​together so that the effective forming width of the scanning galvanometer assembly covers the entire processing plane 1; in this example, all scanning galvanometer units 2 are externally connected to a 2kW fiber laser.

[0058] like Figure 6 As shown, the milling head assembly of the device includes four milling heads 3 arranged in an array along the width direction of the metal powder layer. These milling heads 3 can be driven by a robotic arm to independently reciprocate along the width direction, length direction and thickness direction of the metal powder layer.

[0059] like Figure 7 As shown, the dimension W of the processing width 4 of each milling head 3 along the width direction of the metal powder layer is 300 mm. These processing widths 4 are combined with each other so that the effective processing width of the milling head assembly covers the entire processing plane 1.

[0060] Based on this equipment, the present invention proposes a laser additive and subtractive composite manufacturing method for metal parts, comprising the following steps:

[0061] S1. Slice the three-dimensional digital model of the metal part to obtain the contour data of each slice layer;

[0062] S2, laying the first metal powder layer on the processing plane 1;

[0063] S3. Simultaneously, nine scanning galvanometer units 2 in the device are used to perform parallel and partitioned SLM forming on the first metal powder layer according to the contour data of the first slice layer. The laser power output by each scanning galvanometer unit 2 is set to 2 kW.

[0064] S4, determine whether the first forming layer needs to be machined by milling; after the SLM forming of the first forming layer is completed, if the first forming layer does not need to be machined by milling, then go directly to the next step; if the first forming layer needs to be machined by milling, then Figure 7 As shown, four milling heads 3 are used to synchronously perform mechanical milling on the forming layer until the mechanical milling of the first forming layer is completed; during this period, each milling head 3 is responsible for the mechanical milling of the corresponding processing width 4;

[0065] S5. Referring to steps S2, S3, and S4, the subsequent metal powder layer laying, SLM forming, and mechanical milling of the formed layer are repeated until the laser additive and subtractive composite manufacturing of the metal part is completed.

[0066] In step S4, in order to avoid position interference between the milling heads 3 of adjacent processing widths, two safety zones 6 are symmetrically set on both sides of the joint line 5 of all processing widths 4, such as Figure 5 As shown, their sizes and milling processing sequence are set as follows: (1) The size of the safety zone 6 along the length direction of the metal powder layer is the same as that of the processing width 4; (2) In this example, the size W0 of the safety zone 6 along the width direction of the metal powder layer is set to 60 mm; (3) During the synchronous mechanical milling process of two adjacent processing widths 4, when the mechanical milling processing of one of the safety zones 6 is completed, the mechanical milling processing of the other safety zone 6 is carried out.

[0067] Example 2

[0068] In this example, in order to further improve the forming efficiency of the parts, the SLM forming of the metal powder layer and the mechanical milling of the forming layer can be carried out simultaneously, such as Figure 8 、 Figure 9 As shown, both the scanning galvanometer assembly and the milling head assembly can move above the metal powder layer, so that during the SLM forming process of the metal powder layer, the area of ​​the metal powder layer that has completed SLM forming can be mechanically milled in parallel by multiple milling heads, so that SLM forming and mechanical milling can be carried out simultaneously, shortening the overall processing time of the metal powder layer.

[0069] An embodiment of the present invention provides a laser additive and subtractive composite manufacturing device with multiple milling processes in parallel, which includes a scanning galvanometer assembly, a milling head assembly and a processing plane 1; wherein, the processing plane 1 is used to lay a metal powder layer layer by layer. In this embodiment, the width of the metal powder layer is 1800 mm and the length is 2000 mm; the scanning galvanometer assembly includes 5 scanning galvanometer units 2, which are arranged in a row along the width direction of the metal powder layer. The size of the forming width of each scanning galvanometer unit 2 is 360 mm × 360 mm. The forming widths of these scanning galvanometer units 2 are spliced ​​with each other along the width direction of the metal powder layer, and these scanning galvanometer units 2 can be synchronously moved back and forth along the length direction of the metal powder layer under the guidance of a linear module, so that the effective forming width of the scanning galvanometer assembly covers the entire processing plane 1, and these scanning galvanometer units 2 are all externally connected to a 4kW fiber laser.

[0070] like Figure 8 As shown, the milling head assembly of the device includes six milling heads 3 arranged in an array along the width direction of the metal powder layer. These milling heads 3 can be driven by a multi-axis module to independently reciprocate along the width direction, length direction and thickness direction of the metal powder layer.

[0071] like Figure 9 As shown, the dimension W of the processing width 4 of each milling head 3 along the width direction of the metal powder layer is 300 mm. These processing widths 4 are combined with each other so that the effective processing width of the milling head assembly covers the entire processing plane 1. At the same time.

[0072] Based on this equipment, the present invention proposes a laser additive and subtractive composite manufacturing method for metal parts, comprising the following steps:

[0073] S1. Slice the three-dimensional digital model of the metal part to obtain the contour data of each slice layer;

[0074] S2, laying the first metal powder layer on the processing plane 1;

[0075] S3. First, move five scanning galvanometer units 2 arranged in a row along the width direction of the metal powder layer to above the first metal powder layer. Based on the contour data of the first slice layer, perform parallel and partitioned SLM forming on the metal powder layer within the forming width at the current position of these scanning galvanometer units 2. The laser power output by each scanning galvanometer unit 2 is set to 4 kW. Then, move these scanning galvanometer units 2 to above the metal powder layer that has not yet been SLM-formed. Continue to perform parallel and partitioned SLM forming. The laser power output by each scanning galvanometer unit 2 is still set to 4 kW.

[0076] S4. Determine whether the first forming layer needs to be mechanically milled. If the first forming layer does not need to be mechanically milled, then after the SLM forming of the entire metal powder layer is completed, directly proceed to step S4. If the first forming layer needs to be mechanically milled, then six milling heads 3 are used to synchronously perform mechanical milling on the area where the SLM forming has been completed until the SLM forming and mechanical milling of the first forming layer are all completed. During this period, each milling head 3 is responsible for mechanical milling the area where the SLM forming has been completed on the corresponding processing width 4.

[0077] S5. Referring to steps S2, S3, and S4, the subsequent metal powder layer laying, SLM forming, and mechanical milling of the formed layer are repeated until the laser additive and subtractive composite manufacturing of the metal part is completed.

[0078] In step S4, in order to avoid position interference between the milling heads 3 of adjacent processing widths, two safety zones 6 are symmetrically set on both sides of the joint line 5 of all processing widths 4, such as Figure 5 As shown, their sizes and milling processing sequence are set as follows: (1) The size of the safety zone 6 along the length direction of the metal powder layer is the same as that of the processing width 4; (2) In this embodiment, the size W0 of the safety zone 6 along the width direction of the metal powder layer is set to 30 mm; (3) During the synchronous mechanical milling process of two adjacent processing widths 4, when the mechanical milling process of one of the safety zones 6 is completed, the mechanical milling process of the other safety zone 6 is carried out.

[0079] It will be easily understood by those skilled in the art that the above description is merely 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 scope of protection of the present invention.

Claims

1. Laser additive and subtractive composite manufacturing equipment with multiple milling processes in parallel, characterized by: Including a processing plane, a scanning galvanometer assembly and a milling head assembly; The processing plane is used to lay metal powder layers layer by layer; The scanning galvanometer assembly is used for SLM forming of the metal powder layer and is located above the processing plane, and includes a plurality of scanning galvanometer units. The effective forming widths of the plurality of scanning galvanometer units can be combined to cover the entire processing plane. The milling head assembly is used for milling processing after SLM forming of the metal powder layer and is located between the scanning galvanometer assembly and the processing plane. It includes a plurality of milling heads arranged in an array along the width direction of the metal powder layer. The effective processing widths of the plurality of milling heads are spliced ​​together and cover the entire processing plane. Each of the milling heads can independently reciprocate along the width direction, length direction and thickness direction of the metal powder layer. Two safety zones are symmetrically set on both sides of the processing width joint line of two adjacent milling heads. The dimensions of the two safety zones along the length direction of the metal powder layer are the same as the processing width. The dimension W0 of the two safety zones along the width direction of the metal powder layer and the dimension W of the processing width along the width direction of the metal powder layer meet the relationship: 0.3W ≥ W0 ≥ 0.1W. After the mechanical milling process of one safety zone is completed, the mechanical milling process of the other safety zone is carried out, that is, the adjacent milling heads alternately complete the processing of the safety zones. The number of the scanning galvanometer units is M, and the scanning galvanometer units are movably mounted above the processing plane and arranged in N rows along the width direction of the metal powder layer. Each row contains M / N scanning galvanometer units, where M / N is an integer. The forming widths of the scanning galvanometer units in the same row are mutually spliced, and each row of scanning galvanometer units can reciprocate along the length direction of the metal powder layer, so that the effective forming width of the scanning galvanometer assembly covers the entire processing plane; The area where the metal powder layer has completed SLM forming is mechanically milled in parallel using multiple milling heads, so that SLM forming and mechanical milling can be carried out simultaneously.

2. The laser additive and subtractive composite manufacturing equipment with multiple milling processes in parallel according to claim 1, characterized in that: The scanning galvanometer unit is externally connected to a kilowatt-class high-power fiber laser to perform SLM forming of the metal powder layer.

3. A laser additive-subtractive composite manufacturing method using the laser additive-subtractive composite manufacturing equipment according to any one of claims 1-2, wherein multiple milling processes are performed in parallel, characterized in that: The steps include: S1. Slice the three-dimensional digital model of the metal part to obtain the contour data of each slice layer of the metal part; S2. Laying the first metal powder layer on the processing plane; S3. When M scanning galvanometer units are fixedly installed above the processing plane, each scanning galvanometer unit works simultaneously, and according to the contour data of the first slicing layer, the first metal powder layer is subjected to parallel and partitioned SLM forming as a whole to form the first formed layer; when M scanning galvanometer units are movably installed above the processing plane, each column of scanning galvanometer units needs to be moved above the metal powder layer, and according to the contour data of the first slicing layer, the portion of the metal powder layer located within the effective forming width of each column of scanning galvanometer units is subjected to parallel and partitioned SLM forming, and then each column of scanning galvanometer units is moved in turn to the metal powder layer that has not yet completed SLM forming, and gradually completes the SLM forming of the entire metal powder layer to form the first formed layer; S4, determining whether the first forming layer needs to be milled. If so, multiple milling heads simultaneously mill the first forming layer to complete the processing; if not, proceeding to the next step; S5. Referring to steps S2, S3 and S4, the subsequent metal powder layer laying, SLM forming and milling of the formed layer are repeated in sequence until the additive and subtractive composite manufacturing of the metal part is completed.

4. The laser additive and subtractive composite manufacturing method with multiple milling processes performed in parallel according to claim 3, wherein: In step S3, the laser power output by the scanning galvanometer unit is greater than or equal to 2KW.

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