Additive manufacturing apparatus with multiple powder feeding and recoating units, and additive manufacturing method

Abstract

An additive manufacturing apparatus with multiple powder feeding and recoating units, and an additive manufacturing method. The apparatus comprises a scanning device, a control device, a substrate and a plurality of powder feeding and recoating units. The scanning device is used for performing scan melting on a powder material according to a preset path and process parameters. The substrate is used for bearing the powder material and a workpiece formed by the melting, the whole working area of the upper surface of the substrate that is used for the powder recoating and the scan melting being divided into a plurality of sub-working areas. The control device is used for controlling the scanning device to perform scan melting on some sub-working areas among all the sub-working areas, and simultaneously controlling the powder feeding and recoating units to recoat other sub-working areas with a powder. The present application allows powder recoating and scanning to be simultaneously and independently carried out, that is, powder recoating does not occupy the scanning time of the apparatus, thereby improving the printing efficiency of the apparatus to the maximum extent.

Description

Additive manufacturing equipment with multiple powder feeding and spreading devices and additive manufacturing method

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application with application number 202411291103.8 filed with the Patent Office of China on September 14, 2024, entitled “A kind of additive manufacturing equipment and additive manufacturing method with multi-feeding powder laying device”, the Chinese patent application with application number 202411291123.5 filed with the Patent Office of China on September 14, 2024, entitled “A kind of additive manufacturing equipment and additive manufacturing method with multi-feeding powder laying device”, and the Chinese patent application with application number 202410389220.1 filed with the Patent Office of China on April 2, 2024, entitled “A kind of additive manufacturing equipment and printing method with bidirectional powder laying and same”, all of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of additive manufacturing technology, and in particular to an additive manufacturing device and an additive manufacturing method having a multi-powder feeding and spreading device. Background Art

[0004] Powder bed additive manufacturing (AM) is a rapid manufacturing technology that uses a scanning device to control a heat source to scan and melt powder material layer by layer, stacking them layer by layer to form a three-dimensional solid. The process flow is as follows: First, the three-dimensional model of the workpiece is sliced ​​layer by layer to generate a slice file. The slice file contains the cross-sectional geometry information of each layer, the heat source scanning path, and other process parameters. A layer of powder material is evenly spread on the surface of the substrate. The scanning device selectively melts the powder according to the slice file of the first layer, forming a layer of workpiece solid. Another layer of powder material is evenly spread on the upper surface of this layer of powder and the workpiece solid. The scanning device continues to scan according to the slice file of the next layer to selectively melt the powder. This process is repeated layer by layer, ultimately resulting in a three-dimensional solid.

[0005] In the above technology, the powder feeding and spreading device is responsible for spreading the powder material evenly on the surface of the substrate or the upper surface of the previous layer of powder and the workpiece entity. Generally speaking, the scanning device needs to wait for the powder feeding and spreading device to complete the current layer of powder spreading before starting to selectively scan the molten powder. This waiting time makes it impossible for the scanning device to continuously scan the melt without interruption, which reduces the printing efficiency of the additive manufacturing equipment. In general applications, the time waiting for the completion of powder spreading accounts for 10% to 30% of the additive manufacturing time. Therefore, improving the powder spreading device and optimizing the coordination logic of scanning the melt and spreading the powder are particularly important for improving the printing efficiency of the additive manufacturing equipment. Summary of the Invention

[0006] In order to solve the above-mentioned problems existing in the prior art, the present application provides an additive manufacturing device and an additive manufacturing method with multiple powder feeding and spreading devices. In the additive manufacturing device and method, the powder spreading work and the scanning and melting work can be carried out independently and simultaneously, that is, the scanning and melting process of the scanning device is no longer interrupted by the powder spreading action of the powder feeding and spreading device, thereby maximizing the printing efficiency of the additive manufacturing equipment.

[0007] In order to achieve the above-mentioned objectives, the present application provides an additive manufacturing device with multiple powder feeding and spreading devices, including a scanning device, a control device, a substrate and multiple sets of powder feeding and spreading devices; the scanning device is used to scan the molten powder material according to a predetermined path and process parameters; the substrate is used to carry the powder material and the workpiece formed by the molten material, and the upper surface of the substrate is used for spreading the powder and scanning the melt. The entire working area is divided into multiple sub-working areas; the control device is used to control the scanning device to scan and melt some of the sub-working areas of all the sub-working areas, and at the same time control the powder feeding and spreading device to spread powder on other sub-working areas.

[0008] The present application also provides an additive manufacturing device with multiple powder feeding and spreading devices, which includes a scanning device, a control device, a substrate and multiple sets of powder feeding and spreading devices; the scanning device is used to scan the molten powder material according to a predetermined path and process parameters; the substrate is used to carry the powder material and the workpiece formed by the fusion, and the entire working area on the substrate for spreading the powder and scanning the fusion is divided into multiple sub-working areas, including at least a first sub-working area and a second sub-working area; each set of powder feeding and spreading devices corresponds to a different sub-working area, and is used to spread the powder to the sub-working area; the multiple sets of powder feeding and spreading devices include at least a first powder feeding and spreading device and a second powder feeding and spreading device, the first powder feeding and spreading device is used to spread the powder to the first sub-working area on the substrate, and the second powder feeding and spreading device is used to spread the powder to the second sub-working area on the substrate.

[0009] As an optional solution of the present application, the control device is used to control the scanning device to scan and melt part of all the sub-working areas, and at the same time control the powder feeding and spreading device to spread powder on other sub-working areas.

[0010] As an optional solution of the present application, the shortest distance between the first sub-working area and the second sub-working area is less than or equal to 5 mm.

[0011] As an optional solution of the present application, the multiple sub-working areas of the working area do not overlap with each other.

[0012] As an optional solution of the present application, the powder spreading directions of the multiple sets of powder feeding and spreading devices are the same or opposite, and the working area is divided into multiple non-overlapping sub-working areas along the direction perpendicular to the powder spreading direction.

[0013] As an optional solution of the present application, each set of powder delivery and spreading device includes an arm seat, a scraper seat and two scrapers. The scraper seat is arranged on the arm seat. A powder receiving trough is provided in the scraper seat. The two scrapers are respectively arranged on both sides of the bottom of the powder receiving trough, so that the powder falls into the working area through the powder receiving trough and is flattened to the corresponding sub-working area under the action of the scraper on one side.

[0014] As an optional solution of the present application, the outer sides of the scraper seat away from the arm seat are arc-shaped; the outer sides of the arm seat away from the scraper seat are arc-shaped.

[0015] As an optional solution of the present application, the additive manufacturing equipment also includes a drive system, a transmission system, a linear guide rail and a slider. The guide rail is arranged on a large working plate. The arm seat is connected to the drive system through a transmission system. Each arm seat is arranged on a corresponding slider so that the arm seat and the slider can move parallel to each other on the linear guide rail under the drive of the drive system.

[0016] The present application also provides an additive manufacturing method using any of the above-mentioned additive manufacturing equipment with a multi-feed powder spreading device, in which the geometric model of the workpiece to be manufactured is sliced ​​layer by layer according to a specified layer thickness to obtain the geometric contour and scanning path information of each layer, and then the powder is spread layer by layer and scanned and melted on the substrate according to the scanning path information of each layer, and finally all the workpiece entities are constructed; the layer-by-layer powder spreading and scanning and melting include at least the following steps:

[0017] Step S1: The control device controls the scanning device to scan and melt the current layer in the first sub-working area, and controls the second powder feeding and spreading device to spread the current layer in the second sub-working area;

[0018] Step S2: After scanning and melting are completed in the first sub-working area and powder spreading is completed in the second sub-working area, the control device controls the substrate to descend relative to the powder feeding and spreading device to a height of a specified layer thickness;

[0019] Step S3: The control device controls the scanning device to scan and melt the current layer in the second sub-working area, and controls the first powder feeding and spreading device to spread the next layer in the first sub-working area.

[0020] Step S4: After the scanning and melting of the second sub-working area is completed and the powder spreading of the first sub-working area is completed, the number of layers that have been scanned is increased by one, and the next layer becomes the current layer.

[0021] Step S5: repeat the above steps S1 to S4 until all layers of the workpiece to be manufactured and formed are scanned and melted.

[0022] As an optional solution of the present application, the scanning melting action of step S3 is started after the substrate lowering action in step S2 is completed, or during the substrate lowering process, or before the substrate lowering action.

[0023] As an optional solution of the present application, the method uses the first powder feeding and spreading device and the second powder feeding and spreading device to spread the first layer of powder in the first sub-working area and the second sub-working area on the substrate respectively before scanning and melting the first layer, or only uses the first powder feeding and spreading device to spread the first layer of powder in the first sub-working area on the substrate.

[0024] As an optional solution of the present application, the powder spreading in the method is performed and completed by the powder spreading device in the reciprocating motion relative to the substrate surface, and one motion direction in the reciprocating motion is defined as the positive direction, and the other motion direction is defined as the reverse direction; the powder spreading device only performs and completes a layer of powder spreading during the forward motion, or only performs and completes a layer of powder spreading during the reverse motion, or performs and completes a layer of powder spreading during the forward and reverse motions respectively.

[0025] The present application also provides an additive manufacturing device with multiple powder feeding and spreading devices, which includes at least a scanning device, a control device, a base plate and multiple sets of powder feeding and spreading devices; the scanning device is used to scan the molten powder material according to a predetermined path and process parameters; the upper surface of the base plate provides a working area for carrying the powder material and the workpiece formed by melting, and each set of powder feeding and spreading devices is used to spread the powder material according to a specified layer thickness to the corresponding powder spreading range in the working area. There is an overlapping area between the powder spreading ranges of adjacent powder feeding and spreading devices, and the sum of the powder spreading ranges of all powder feeding and spreading devices covers at least the entire working area; the working area is divided into multiple sub-working areas, so that the control device is used to control the scanning device and the multiple sets of powder feeding and spreading devices to realize the scanning, melting and powder spreading of the sub-working areas according to a predetermined logic.

[0026] As an optional solution of the present application, the control device controls the scanning device to scan and melt part of the sub-working areas in the working area, and controls the powder feeding and spreading device to spread powder on another part of the sub-working areas.

[0027] As an optional solution of the present application, the sub-working areas are arranged perpendicular to the powder spreading direction.

[0028] As an optional solution of the present application, the multiple sets of powder feeding and spreading devices include a first powder feeding and spreading device and a second powder feeding and spreading device, and there is an overlapping area in the powder spreading ranges of the first powder feeding and spreading device and the second powder feeding and spreading device; the working area is divided into four sub-working areas, namely A1 area, A2 area, B1 area, and B2 area; the A1 area is the area within the powder spreading range of the first powder feeding and spreading device except the overlapping area and not interfered with by the second powder feeding and spreading device; the A2 area includes the area within the powder spreading range of the first powder feeding and spreading device except the overlapping area and interfered with by the second powder feeding and spreading device, as well as a part of the overlapping area; the B1 area is the area within the powder spreading range of the second powder feeding and spreading device except the overlapping area and not interfered with by the first powder feeding and spreading device; the B2 area includes the area within the powder spreading range of the second powder feeding and spreading device except the overlapping area and interfered with by the first powder feeding and spreading device, as well as the remaining part of the overlapping area; the control device is used to control the scanning device and the two sets of powder feeding and spreading devices to realize scanning, melting and powder spreading of the A1 area, A2 area, B1 area, and B2 area according to a predetermined logic.

[0029] As an optional solution of the present application, the powder spreading ranges of the first powder feeding and spreading devices are the same in size, and the center line of the overlapping area is used as the boundary line between the A2 area and the B2 area.

[0030] As an optional solution of the present application, it also includes a motion mechanism for providing the first powder feeding and spreading device and the second powder feeding and spreading device with at least the motion function of translation in the vertical direction along the powder spreading direction; or for providing the first powder feeding and spreading device and the second powder feeding and spreading device with at least the motion function of rotation around the normal surface of their working area.

[0031] The present application also provides an additive manufacturing method for an additive manufacturing device having a multi-feed powder spreading device, wherein a geometric model of a workpiece to be manufactured is sliced ​​layer by layer according to a specified layer thickness to obtain geometric contours and scanning path information of each layer, and then powder is spread layer by layer and scan-fused on a substrate according to the scanning path information of each layer, and finally all workpiece entities are constructed; the layer-by-layer powder spreading and scanning-fusion at least comprises the following steps:

[0032] Step S1: The control device controls the scanning device to perform scanning and melting of the current layer on the A2 area;

[0033] Step S2: The control device controls the scanning device to perform scanning and melting of the current layer on the A1 area, and controls the second powder feeding and spreading device to perform powder spreading of the current layer on the B1 and B2 areas;

[0034] Step S3: The control device controls the substrate to descend relative to the powder feeding device to a height of a specified layer thickness, and controls the scanning device to perform scanning and melting of the current layer in the B2 area;

[0035] Step S4: The control device controls the scanning device to perform scanning and melting of the current layer on the B1 area, and controls the first powder feeding and spreading device to perform powder spreading of the next layer on the A1 and A2 areas.

[0036] Step S5: After the scanning, melting and powder spreading of the previous step are completed, the number of layers that have completed scanning and melting is increased by one, and the next layer becomes the current layer;

[0037] Step S6: Repeat steps S1-S5 until all layers of the workpiece to be manufactured are scanned and melted.

[0038] As an optional solution of the present application, the scanning melting action in step S3 is started after the substrate descends, or during the substrate descending process, or before the substrate descends.

[0039] As an optional solution of the present application, if the scanning melting in step S3 has been completed and the substrate lowering action is still in progress, the scanning melting action in step S4 starts immediately or waits until the substrate lowering action is completed before starting.

[0040] As an optional solution of the present application, when the substrate descends relative to the powder feeding and spreading device in step S3, the scanning device scanning the B2 area and the B1 area descends synchronously or dynamically zooms to keep the distance between the heat source focus and the molten powder to be scanned unchanged.

[0041] As an optional solution of the present application, the powder spreading is performed and completed by the powder feeding and spreading device in the reciprocating motion relative to the working area, and one motion direction in the reciprocating motion is defined as the positive direction, and the other motion direction is defined as the reverse direction; the powder feeding and spreading device only performs and completes one layer of powder spreading during the forward motion, or only performs and completes one layer of powder spreading during the reverse motion, or performs and completes one layer of powder spreading during the forward and reverse motions respectively.

[0042] As an optional solution of the present application, when one of the two powder delivery and spreading devices is performing the powder spreading work, the other set of powder delivery and spreading device takes the following actions in advance to avoid motion interference: through the motion mechanism, it makes itself translate at least in the direction perpendicular to the powder spreading direction, or through the motion mechanism, it makes itself rotate at least around the normal direction of the working area surface, or continues to move in the powder spreading direction or in the opposite direction after completing its last powder spreading action.

[0043] As an optional solution of the present application, the boundaries of adjacent sub-working areas are changed layer by layer according to the manufacturing process requirements.

[0044] The additive manufacturing equipment and additive manufacturing method with a multi-feeding powder spreading device of the present application, by adopting the above technical solution, have the following beneficial effects:

[0045] 1. In the present application, the first powder feeding and spreading device respectively feed and spread powder to the corresponding sub-working areas, so that the scanning and melting work and the powder spreading work can be alternately performed on the sub-working areas (e.g., the first sub-working area and the second sub-working area) of the working area until the workpiece is printed. In this way, the powder spreading work and the scanning and melting work can be performed simultaneously and independently, that is, the scanning and melting process of the scanning device is no longer interrupted by the powder spreading action of the powder feeding and spreading device, and can continue to work uninterruptedly, thereby maximizing the powder melting deposition efficiency, that is, the printing efficiency of the additive manufacturing equipment;

[0046] 2. The multi-feed powder spreading device of this application is a technical upgrade of the original additive manufacturing equipment equipped with a single-feed powder spreading device, which significantly improves the printing efficiency.

[0047] 3. The additive manufacturing equipment with a multi-feed powder spreading device of the present application is compatible with one-way powder spreading and two-way powder spreading functions;

[0048] 4. In the present application, multiple powder feeding and spreading devices are included, each of which is used to spread the powder material to a specified layer thickness in a corresponding powder spreading range within the working area. The powder spreading ranges of adjacent powder feeding and spreading devices overlap. This allows the powder spreading and scanning and melting operations to be performed simultaneously and independently. That is, the scanning and melting process of the scanning device is no longer interrupted by the powder spreading action of the powder feeding and spreading device and can continue to operate uninterrupted, thereby maximizing the powder melting deposition efficiency, that is, the printing efficiency of the additive manufacturing equipment.

[0049] 5. In this application, the working area on the surface of the substrate used for powder spreading can be fully used for scanning and melting. There is no area that cannot be used for scanning and melting due to interference from the movement of the powder feeding and spreading device or overflow of powder during powder spreading. This improves the space utilization of the substrate on the one hand, and allows the additive manufacturing equipment to form larger workpieces on the other hand. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] FIG1 is a schematic structural diagram of an embodiment of an additive manufacturing device provided by the present application having multiple powder feeding and spreading devices;

[0051] FIG2 is a schematic structural diagram of a powder feeding and spreading device according to an embodiment of an additive manufacturing apparatus with multiple powder feeding and spreading devices provided by the present application;

[0052] FIG3 is a flow chart of an embodiment of an additive manufacturing method with a multi-powder feeding and spreading device provided by the present application;

[0053] FIG4 is a flow chart of a method of Example 1 of the additive manufacturing method with a multi-feeding powder spreading device provided in the present application;

[0054] FIG5 is a flow chart of a method of embodiment 2 of the additive manufacturing method with a multi-feeding powder spreading device provided in the present application;

[0055] FIG6 is a schematic diagram of the structure of the additive manufacturing equipment according to the third embodiment of the present application;

[0056] FIG7 is a schematic diagram of the working area division of Example 3 provided in this application;

[0057] FIG8 is a schematic diagram of the structure of the powder feeding and spreading device using a translational motion mechanism to avoid interference in the fourth embodiment provided by the present application;

[0058] FIG9 is a schematic structural diagram of a powder feeding and spreading device using a rotary motion mechanism to avoid interference in the fifth embodiment provided by the present application;

[0059] FIG10 is a flowchart of the additive manufacturing method according to Example 6 of the present application;

[0060] FIG11 is a schematic diagram of the dynamic division of working areas in Example 7 provided in this application;

[0061] FIG12 is a schematic structural diagram of a scraper of a powder feeding and spreading device provided in an additive manufacturing apparatus with multiple powder feeding and spreading devices according to an embodiment of the present application.

[0062] Markings in the figure: 1. Working plate, 2. First sub-working area, 3. First powder feeding and spreading device, 4. Transmission system, 5. Drive system, 6. Powder overflow trough, 7. Second powder feeding and spreading device, 8. Second sub-working area, 9. Scraper seat, 10. Powder receiving trough, 11. Scraper, 12. Pressing plate, 13. Screw, 14. Arm seat, 15. Working area, 16 Overlapping area, 17. First interference area, 18. Second interference area, 19. Translational motion mechanism, 20. Rotational motion mechanism, 21. Workpiece cross section. DETAILED DESCRIPTION

[0063] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0064] As shown in Figures 1 and 2, the additive manufacturing equipment with multiple powder feeding and spreading devices includes a scanning device, a control device, a substrate and multiple sets of powder feeding and spreading devices; the scanning device is used to scan the molten powder material according to a predetermined path and process parameters; the substrate is used to carry the powder material and the workpiece formed by melting, and the entire working area on the substrate for spreading powder and scanning the melting is divided into multiple sub-working areas, including at least a first sub-working area 2 and a second sub-working area 8; each set of powder feeding and spreading devices corresponds to a different sub-working area, used to spread the powder to the sub-working area; the multiple sets of powder feeding and spreading devices include at least a first powder feeding and spreading device 3 and a second powder feeding and spreading device 7, the first powder feeding and spreading device 3 is used to spread the powder to the first sub-working area 2 on the substrate, and the second powder feeding and spreading device 7 is used to spread the powder to the second sub-working area 8 on the substrate; the control device is used to control the scanning device to scan and melt some of the sub-working areas of all the sub-working areas, and at the same time control the powder feeding and spreading device to spread powder to other sub-working areas.

[0065] In a specific implementation, the number of sub-working areas is the same as the number of powder feeding and spreading devices, and they correspond one to one; the scanning device may include at least one scanning system. In actual use, the specific number can be selected according to the area of ​​the working area, and there is no restriction on it here. Specifically, the multiple sub-working areas of the working area overlap or do not overlap with each other, preferably do not overlap with each other. The scanning device of the present application may use a laser as a heat source, or an arc, an electron beam, etc. as a heat source. The powder feeding and spreading device may use a powder supply cylinder and a roller to feed the powder, or an upper powder feeding system and a scraper to feed the powder. The present application does not limit the structure of the scanning device and the powder feeding and spreading device, as long as it has a scanning function or a powder feeding and spreading function. The substrate and the working area of ​​the present application may be circular, square, etc., and the sub-working area may be square. It should be noted that the specific shapes of the substrate, the working area and the sub-working area can be selected according to specific needs, and there is no restriction on them here. The above-mentioned multiple sets of powder feeding and spreading devices refer to two or more sets of powder feeding and spreading devices.

[0066] Specifically, the shortest distance between the first sub-working area 2 and the second sub-working area 8 is less than or equal to 5 mm. Preferably, the shortest distance between the first sub-working area 2 and the second sub-working area 8 is greater than 0 and less than or equal to 5 mm, so that a safe distance is left between the two sets of powder feeding and spreading devices, thereby ensuring that the powder spreading and printing operations between the first sub-working area 2 and the second sub-working area 8 do not interfere with each other, thereby ensuring the quality of the printed parts. It is understood that when the work packages of the printed parts are arranged, the area between the first sub-working area 2 and the second sub-working area 8 may not contain the workpieces to be printed.

[0067] Optionally, the powder spreading directions of the multiple sets of powder feeding and spreading devices are the same or opposite, so that they can be flexibly set according to the manufacturing requirements of the workpiece to be printed; the working area is divided into multiple non-overlapping sub-working areas along the vertical direction of the powder spreading direction. Optionally, the working area includes a first sub-working area 2 and a second sub-working area 8, and the first sub-working area 2 and the second sub-working area 8 are equal in area. In this way, the working time difference between the first sub-working area 2 and the second sub-working area 8 can be minimized to minimize the waiting time, thereby improving the forming efficiency of the equipment. Of course, in specific implementation, the sizes of the first sub-working area 2 and the second sub-working area 8 can also be designed to be unequal according to specific needs, and this is not limited here.

[0068] Referring to Figure 2, the two sets of powder feeding and spreading devices have the same structure and work independently of each other. Each set of powder feeding and spreading devices includes an arm support 14, a scraper support 9 and two scrapers 11. The scraper support 9 is arranged on the arm support 14. A powder receiving trough 10 is provided in the scraper support 9. The two scrapers 11 are respectively arranged on both sides of the bottom of the powder receiving trough 10, so that the powder falls into the working area through the powder receiving trough 10 and is flattened to the corresponding sub-working area under the action of the scraper 11 on one side. The additive manufacturing equipment also includes a drive system 5, a transmission system 4, a linear guide rail and a slider. The guide rail is arranged on the working plate 1. The arm support 14 is connected to the drive system 5 through the transmission system 4. Each arm support 14 is arranged on the corresponding slider so that the arm support 14 and the slider move parallel to each other on the linear guide rail under the drive of the drive system 5. Specifically, the drive system 5 is a servo motor, and the transmission system 4 includes a reducer, a reducer fixing seat, master and slave pulleys, and a synchronous belt. The reducer is installed on the reducer fixing seat, and the synchronous belt is wound on the master and slave pulleys. The reducer, driven by the servo motor, drives the arm seat 14 to translate through the synchronous belt, thereby driving the scraper 11 to move on the corresponding sub-working area to spread powder. Of course, in specific implementations, the drive system 5 and transmission system 4 can also have other specific structures, which are not listed here one by one.

[0069] Optionally, further referring to Figure 2, the outer sides of the scraper seat 9 away from the arm seat 14 are arc-shaped; the outer sides of the arm seat 14 away from the scraper seat 9 are arc-shaped. This structural design can reduce the impact of the wind field disturbance caused by the scraper 11 during movement on the normal printing of another sub-working area, thereby improving the printing quality.

[0070] In a specific implementation, the powder feeding device further includes two pressing plates 12 and two screws 13 , and each scraper 11 is fixed to the bottom of the scraper seat 9 by the pressing plates 12 and the screws 13 .

[0071] In another specific embodiment, the additive manufacturing equipment further includes an overflow powder trough 6, which is arranged on one side or both sides of the working area, so that the excess powder generated during the powder spreading process and the fine smoke and dust particles generated on the powder bed after printing are pushed to the overflow powder trough 6 by the scraper 11. It should be noted here that, as shown in Figure 1, there is one overflow powder trough 6. At this time, the powder receiving trough 10 is located on the right side of the working area and on the left side of the overflow powder trough 6, and receives powder greater than two layers of thickness from the powder feeding system (not shown in the figure) each time, and after two layers of powder are spread from right to left and from left to right by the double scrapers 11, the excess powder is pushed to the overflow powder trough 6. Of course, the overflow powder trough 6 can also be two, respectively arranged on both sides of the working area. In this case, there are also two powder feeding systems, respectively arranged on both sides of the working area, so that the powder receiving trough 10 receives powder greater than one layer of thickness from the powder feeding system each time, and after the layer of powder is spread by the scraper 11, the excess powder is pushed to the corresponding overflow powder trough 6. It is understandable that the present application optionally adopts a powder feeding trough and a powder feeding system, which can make the overall structure of the equipment more compact, simpler and lower in cost.

[0072] It should be noted here that the number of powder feeding and spreading devices and sub-working areas of the present application can be two or more. For example, as the size of the workpiece to be manufactured increases, the working area also increases accordingly, and the number of powder feeding and spreading devices and sub-working areas can also be increased accordingly, such as three, four, and so on.

[0073] As shown in FIG3 , the present application further provides a printing method using an additive manufacturing device with a multi-feed powder spreading device according to any of the above embodiments. In this method, a geometric model of a workpiece to be manufactured (also referred to as a workpiece to be printed or a workpiece to be printed) is sliced ​​and layered according to a specified layer thickness to obtain the geometric contour and scanning path information of each layer. Then, powder is spread and scanned and melted layer by layer on a substrate according to the scanning path information of each layer, and finally all workpiece entities are constructed; the layer-by-layer powder spreading and scanning and melting include at least the following steps:

[0074] Step S1: The control device controls the scanning device to scan and melt the current layer in the first sub-working area, and controls the second powder feeding and spreading device to spread the current layer in the second sub-working area;

[0075] Step S2: After scanning and melting are completed in the first sub-working area and powder spreading is completed in the second sub-working area, the control device controls the substrate to descend relative to the powder feeding and spreading device to a height of a specified layer thickness;

[0076] Step S3: The control device controls the scanning device to scan and melt the current layer in the second sub-working area, and controls the first powder feeding and spreading device to spread the next layer in the first sub-working area.

[0077] Step S4: After the scanning and melting of the second sub-working area is completed and the powder spreading of the first sub-working area is completed, the number of layers that have been scanned is increased by one, and the next layer becomes the current layer;

[0078] Step S5: repeat the above steps S1 to S4 until all layers of the workpiece to be manufactured and formed are scanned and melted.

[0079] This method describes the technical solution of this application based on two sets of powder feeding and spreading devices and two sub-working areas. For more than two sets of powder feeding and spreading devices and more than two sub-working areas, this method can be used as a reference.

[0080] In a specific implementation, the scanning and melting action of step S3 is started after the substrate lowering action in step S2 is completed, or during the substrate lowering process, or before the substrate lowering action. In order to further improve the printing efficiency, it is optional to not have to wait for the substrate lowering action in step S2 to be completed before starting the scanning and melting of step S3, that is, the scanning and melting of step S3 can be executed simultaneously with the substrate lowering action in step S2 or in advance.

[0081] It should be noted that the core of the protection of this application is that the application includes multiple sets of powder feeding and spreading devices (for example, a first powder feeding and spreading device and a second powder feeding and spreading device), and the multiple sets of powder feeding and spreading devices respectively feed and spread powder to the corresponding sub-working areas, so that the control device controls the scanning device to scan and melt some of the sub-working areas of all the sub-working areas, and at the same time controls the powder feeding and spreading device to spread powder to other sub-working areas, which can save waiting time and thus improve printing efficiency. It should be noted that in the forming process of the workpiece to be printed, the printing of most layers is repeated with reference to this idea, and only the printing steps of some layers, such as the first layer and the last layer, may be slightly different from this repeated step, which can be specifically implemented according to the specific situation. For example, before scanning and melting the first layer, the first powder feeding and spreading device 3 and the second powder feeding and spreading device 7 are used to spread the first layer of powder on the first sub-working area 2 and the second sub-working area 8 on the substrate respectively, or only the first powder feeding and spreading device 3 is used to spread the first layer of powder on the first sub-working area 2 on the substrate.

[0082] Moreover, the powder spreading is performed and completed by the powder spreading device in the reciprocating motion relative to the substrate surface, and one motion direction in the reciprocating motion is defined as the positive direction, and the other motion direction is defined as the reverse direction; the powder spreading device only performs and completes one layer of powder spreading during the forward motion, or only performs and completes one layer of powder spreading during the reverse motion (i.e., one-way powder feeding), or performs and completes one layer of powder spreading during the forward and reverse motions respectively (i.e., two-way powder feeding).

[0083] In order to enable those skilled in the art to better understand and implement the technical solution of the present application, the technical solution of the printing method of the additive manufacturing equipment using a single / bidirectional powder feeding and spreading device of the present application is specifically described in the form of an embodiment below.

[0084] Example 1

[0085] As shown in FIG4 , this embodiment is a printing method of an additive manufacturing device with a one-way powder feeding device, which includes the following steps:

[0086] Step 1: The first powder feeding and spreading device 3 spreads the powder to the first sub-working area 2 to complete the first layer of powder spreading in the first sub-working area 2, while the second powder feeding and spreading device 7 spreads the powder to the second sub-working area 8;

[0087] Step 2: The control device controls the scanning device to scan and melt the first sub-working area 2, and controls the second powder feeding and spreading device 7 to spread powder on the second sub-working area 8;

[0088] Step 3: When the first sub-working area 2 completes the scanning and melting of the current layer, and the second sub-working area 8 completes the powder spreading of the current layer, the substrate is controlled to descend by a specified layer thickness;

[0089] Step 4: The control device controls the second sub-working area 8 to complete the scanning and melting of the current layer, and controls the first powder feeding device 3 to spread the next layer of powder in the first sub-working area 2;

[0090] Step 5: Determine whether the workpiece to be manufactured is printed. If so, end the process. If not, return to execute the above step 2.

[0091] It should be noted that although the above steps 1 and 2 apply powder to the second sub-working area 8 twice, since the substrate does not descend, only one layer of the specified thickness is applied in each application. In addition, since the powder feeding device of this embodiment is a one-way powder feeding device, the powder feeding device needs to move from left to right each time, and then perform another powder spreading operation from right to left, as shown in Figure 4.

[0092] Example 2

[0093] As shown in FIG5 , this embodiment is a printing method of an additive manufacturing device with a bidirectional powder feeding device, which includes the following steps:

[0094] Step 1: The first powder feeding and spreading device 3 spreads the powder to the first sub-working area 2 to complete the first layer of powder spreading in the first sub-working area 2, while the second powder feeding and spreading device 7 spreads the powder to the second sub-working area 8;

[0095] Step 2: The control device controls the scanning device to scan and melt the first sub-working area 2, and controls the second powder feeding and spreading device 7 to spread powder on the second sub-working area 8;

[0096] Step 3: When the first sub-working area 2 completes the scanning and melting of the current layer, and the second sub-working area 8 completes the powder spreading of the current layer, the substrate is controlled to descend by a specified layer thickness;

[0097] Step 4: The control device controls the second sub-working area 8 to complete the scanning and melting of the current layer, and controls the first powder feeding device 3 to spread the next layer of powder in the first sub-working area 2;

[0098] Step 5: Determine whether the workpiece to be manufactured is printed. If so, end the process; if not, proceed to the next step.

[0099] Step 6: The control device controls the scanning device to scan and melt the first sub-working area 2, and controls the second powder feeding and spreading device 7 to spread powder on the second sub-working area 8;

[0100] Step 7: When the first sub-working area 2 completes the scanning and melting of the current layer, and the second sub-working area 8 completes the powder spreading of the current layer, the substrate is controlled to descend by a specified layer thickness;

[0101] Step 8: The control device controls the second sub-working area 8 to complete the scanning and melting of the current layer, and controls the first powder feeding device 3 to spread the next layer of powder in the first sub-working area 2;

[0102] Step 9: Determine whether the workpiece to be manufactured is printed. If so, end the process. If not, return to the above step 2.

[0103] It should be noted that, although the second sub-working area 8 is powdered twice in the above steps 1 and 2, since the substrate does not descend, only one layer of specified thickness is spread in the two powder spreading operations.

[0104] As shown in FIG6 , the additive manufacturing equipment with multiple powder feeding and spreading devices of the present application comprises at least a scanning device, a control device, a base plate and multiple sets of powder feeding and spreading devices; the scanning device is used to scan the molten powder material according to a predetermined path and process parameters; the upper surface of the base plate provides a working area 15 for carrying the powder material and the workpiece formed by melting; each set of powder feeding and spreading devices is used to spread the powder material to the corresponding powder spreading range in the working area 15 according to a specified layer thickness, and the powder spreading ranges of adjacent powder feeding and spreading devices have overlapping areas 16, and the sum of the powder spreading ranges of all powder feeding and spreading devices covers at least the entire working area 15; the working area 15 is divided into multiple sub-working areas, so that the control device is used to control the scanning device and the multiple sets of powder feeding and spreading devices to realize the scanning, melting and powder spreading of the sub-working areas according to a predetermined logic. In the laser powder bed melting additive manufacturing process, the control device refers to a control unit such as an industrial computer, a PLC, and a galvanometer control card.

[0105] In a specific implementation, the multiple sub-working areas are arranged perpendicular to the powder spreading direction. Optionally, the control device controls the scanning device to scan some of the sub-working areas in the working area 15, while controlling the powder feeding and spreading device to spread powder on another part of the sub-working areas. This allows the powder spreading and scanning and melting processes to be performed simultaneously and independently. That is, the scanning and melting process of the scanning device is no longer interrupted by the powder spreading action of the powder feeding and spreading device, and can continue to operate uninterrupted, thereby maximizing the powder melting deposition efficiency, that is, the printing efficiency of the additive manufacturing device.

[0106] As an embodiment of the present application, the multiple sets of powder feeding and spreading devices include a first powder feeding and spreading device 3 and a second powder feeding and spreading device 7, and there is an overlapping area 16 in the powder spreading range of the first powder feeding and spreading device 3 and the second powder feeding and spreading device 7; there is interference between the first powder feeding and spreading device 3 and the second powder feeding and spreading device 7, and the interference method is not limited to one set of powder feeding and spreading devices causing the scanning melting action of some positions within the powder spreading range of the other set of powder feeding and spreading devices to be physically blocked or the powder layer thickness of some positions to change when the powder feeding and spreading device moves or spreads powder; therefore, in addition to the overlapping area 16, there is also an area interfered by the second powder feeding and spreading device 7 (referred to as the first interference area 17) within the powder spreading range of the first powder feeding and spreading device 3, and in addition to the overlapping area 16, there is also an area interfered by the second powder feeding and spreading device 7 within the powder spreading range of the second powder feeding and spreading device 7 There is also an area interfered with by the first powder feeding device 3 (referred to as the second interference area 18); therefore, according to the interference between the first powder feeding device 3 and the second powder feeding device 7, the working area 15 is divided into four sub-working areas, namely area A1, area A2, area B1, and area B2; the area A1 is the area within the powder spreading range of the first powder feeding device 3 excluding the overlapping area 16 and the first interference area 17; the area A2 includes the first interference area 17 and part of the overlapping area 16; the area B1 is the area within the powder spreading range of the second powder feeding device 7 excluding the overlapping area 16 and the second interference area 18; the area B2 includes the second interference area 18 and the remaining part of the overlapping area 16. Finally, the working area 15 is divided into area A1, area A2, area B1, and area B2 as shown in Figure 2. This division is closely related to the subsequent additive manufacturing method. By optimizing the scanning, melting, and powder spreading order of each area, the waiting time for the scanning and melting action to the powder spreading action in the conventional additive manufacturing method can be avoided, thereby improving printing efficiency.

[0107] Optionally, the powder spreading ranges of the first powder feeding and spreading device 3 and the second powder feeding and spreading device 7 are the same size, and the center line of the overlapping area 16 is used as the dividing line between the A2 area and the B2 area, thereby allowing the first powder feeding and spreading device 3 and the second powder feeding and spreading device 7 to use the same mechanical structure, thereby facilitating equipment manufacturing and facilitating the even distribution of scanning melting tasks.

[0108] The control device is used to control the scanning device and two sets of powder feeding and spreading devices to realize scanning, melting and powder spreading of the A1 area, A2 area, B1 area and B2 area according to a predetermined logic.

[0109] As an optional solution of the present application, it also includes a motion mechanism for providing the first powder feeding and spreading device 3 and the second powder feeding and spreading device 7 with at least the motion function of translation in the vertical direction of their powder spreading direction; or for providing the first powder feeding and spreading device 3 and the second powder feeding and spreading device 7 with at least the motion function of rotation around the surface normal of their working area 15, so that one set of powder feeding and spreading devices can take corresponding translational motion or rotational motion to avoid the other set of powder feeding and spreading devices when spreading powder, thereby avoiding motion interference between the two. It can be understood that the motion mechanism of the present application is used to provide the first powder feeding and spreading device 3 and the second powder feeding and spreading device 7 with motion functions such as translation, oblique movement, and rotation, respectively, so as to avoid motion interference between the two. Optionally, it is used to provide the first powder feeding and spreading device 3 and the second powder feeding and spreading device 7 with the motion function of translation parallel to the substrate and perpendicular to the powder spreading direction, or the motion function of translation perpendicular to the substrate and perpendicular to the powder spreading direction, which is simple to operate and more labor-saving.

[0110] It is understood that the division of sub-working areas such as area A1, area A2, area B1, and area B2 can be further optimized, and the boundaries of adjacent sub-working areas can change layer by layer according to the manufacturing process requirements. For details, please refer to Example 7 below in this application. It should be noted that the boundaries of adjacent sub-working areas can change at each layer, randomly, or every few layers, depending on the manufacturing process, so as to further avoid the formation of manufacturing defects on the boundary lines.

[0111] Specifically, the powder spreading directions of the multiple sets of powder feeding and spreading devices are the same or opposite, so they can be flexibly arranged according to the manufacturing requirements of the workpiece to be printed.

[0112] In one specific embodiment, as shown in FIG2 , each set of powder feeding and spreading devices includes an arm support 14, a scraper support 9, and two scrapers 11. The scraper support 9 is disposed on the arm support 14. A powder receiving trough 10 is provided in the scraper support 9. The two scrapers 11 are respectively disposed on both sides of the bottom of the powder receiving trough 10, so that the powder falls through the powder receiving trough 10 to the working area 15 and is flattened to the corresponding sub-working area under the action of the scraper 11 on one side. The additive manufacturing equipment also includes a drive system, a transmission system, a linear guide rail, and a slider. The guide rail is disposed on a large working plate. The arm support 14 is connected to the drive system via a transmission system. Each arm support 14 is disposed on a corresponding slider so that the arm support 14 and the slider move parallel to each other on the linear guide rail under the drive of the drive system. Specifically, the drive system is a servo motor, and the transmission system includes a reducer, a reducer fixing seat, master and slave pulleys, and a synchronous belt. The reducer is installed on the reducer fixing seat, and the synchronous belt is wound around the master and slave pulleys. The reducer, driven by the servo motor, drives the arm seat 14 to translate through the synchronous belt, thereby driving the scraper 11 to move on the corresponding sub-working area to spread powder. Of course, in specific implementations, the drive system and transmission system can also have other specific structures, which are not listed here one by one.

[0113] Optionally, further referring to Figure 2, the outer sides of the scraper seat 9 away from the arm seat 14 are arc-shaped; the outer sides of the arm seat 14 away from the scraper seat 9 are arc-shaped. This structural design can reduce the impact of the wind field disturbance caused by the scraper 11 during movement on the normal printing of another sub-working area, thereby improving the printing quality.

[0114] In a specific implementation, the powder feeding device further includes two pressing plates 12 and two screws 13 , and each scraper 11 is fixed to the bottom of the scraper seat 9 by the pressing plates 12 and the screws 13 .

[0115] Optionally, the bottom surface of the scraper 11 is designed as two parallel planes with a certain height difference, see Figure 12. The height difference can prevent the bottom surface of the scraper from colliding with the workpiece or powder in the scanned melted area. For details, see Example 6 below in this application.

[0116] It should be noted here that the above is a specific optional structure of the powder feeding and spreading device. In specific implementation, it can also be other structures with powder feeding and spreading functions in the prior art, which will not be elaborated in this application.

[0117] The present application also provides an additive manufacturing method using the additive manufacturing apparatus with a multi-feed powder spreading device as described in any of the above embodiments, wherein the method slices the geometric model of the workpiece to be manufactured in layers according to a specified layer thickness to obtain the geometric contour and scanning path information of each layer, and then spreads powder layer by layer and scans and melts it on the substrate according to the scanning path information of each layer, and finally constructs all workpiece entities; the layer-by-layer powder spreading and scanning and melting at least include the following steps:

[0118] Step S1: The control device controls the scanning device to perform scanning and melting of the current layer on the A2 area;

[0119] Step S2: The control device controls the scanning device to perform scanning and melting of the current layer on the A1 area, and controls the second powder feeding and spreading device 7 to perform powder spreading of the current layer on the B1 and B2 areas;

[0120] Step S3: The control device controls the substrate to descend relative to the powder feeding device to a height of a specified layer thickness, and controls the scanning device to perform scanning and melting of the current layer in the B2 area;

[0121] Step S4: The control device controls the scanning device to perform scanning and melting of the current layer on the B1 area, and controls the first powder feeding device 3 to perform powder spreading of the next layer on the A1 and A2 areas;

[0122] Step S5: After the scanning, melting and powder spreading of the previous step are completed, the number of layers that have completed scanning and melting is increased by one, and the next layer becomes the current layer.

[0123] Step S6: Repeat steps S1-S5 until all layers of the workpiece to be manufactured are scanned and melted.

[0124] The scanning and melting action in the above step S3 can be performed after the substrate descends, or it can be started during the substrate's descent, or before the substrate descends. Optionally, starting during the substrate's descent, or before the substrate descends, can further reduce the waiting time for scanning and melting and improve printing efficiency. The feasibility of this approach stems from the fact that in some types of additive manufacturing, such as laser powder bed melting additive manufacturing, the layer thickness of the substrate descending is generally small, on the order of 10-100μm, which is much smaller than the distance from the laser light outlet of the scanning device to the powder surface and smaller than the Rayleigh length of the laser. Scanning and melting while the substrate descends has no significant effect on the printing quality of the part.

[0125] Similarly, if the scanning melting in step S3 has been completed and the substrate lowering action is still in progress, the scanning melting action in step S4 can be started immediately or wait for the substrate lowering action to be completed before starting. Optionally, if the scanning melting in step S3 has been completed and the substrate lowering action is still in progress, the scanning melting action in step S4 can be started immediately, which can further save waiting time and thus improve printing efficiency.

[0126] In order to further improve the printing quality, when the substrate descends relative to the powder feeding device in step S3, the scanning device scanning the B2 area and the B1 area descends synchronously or dynamically zooms to keep the distance between the heat source focus and the molten powder to be scanned unchanged.

[0127] It should be noted that the powder feeding device performs and completes the powder spreading action during the reciprocating motion relative to the working area 15, and the aforementioned layer-by-layer powder spreading and scanning melting process does not limit the powder feeding device to unidirectional or bidirectional powder spreading. Specifically, one direction of movement in the reciprocating motion can be defined as the forward direction, and the other direction of movement can be defined as the reverse direction; the powder feeding device performs and completes the powder spreading of one layer only during the forward direction, or performs and completes the powder spreading of one layer only during the reverse direction, or performs and completes the powder spreading of one layer during both the forward and reverse directions.

[0128] Because the two powder feeding and spreading devices have overlapping powder spreading areas, namely, overlapping area 16, there is a certain amount of motion interference between the two powder feeding and spreading devices. Preferably, when the first powder feeding and spreading device 3 is performing the powder spreading operation, the second powder feeding and spreading device 7 takes the following actions in advance to avoid motion interference: using a motion mechanism to make itself translate at least in a direction perpendicular to the powder spreading direction, or using a motion mechanism to make itself rotate at least in a normal direction around the surface of the working area 15, or continuing to move in the powder spreading direction or in the opposite direction after completing its last powder spreading action.

[0129] It should be noted here that the above description uses two sets of powder feeding and spreading devices as an example to describe at least the steps included in layer-by-layer powder spreading and scanning melting. In specific implementation, as the forming size of the workpiece to be manufactured increases, the additive manufacturing equipment may include three, four or more sets of powder feeding and spreading devices, and the multiple sets of powder feeding and spreading devices can be executed with reference to the execution steps of the above two sets of powder feeding and spreading devices.

[0130] In order to enable those skilled in the art to better understand and implement the technical solution of the present application, the technical solution of the present application is described in detail below in the form of embodiments and drawings.

[0131] Example 3:

[0132] As shown in Figure 6, the additive manufacturing equipment with multiple powder feeding and spreading devices in this embodiment includes a scanning device, a control device, a base plate, a first powder feeding and spreading device 3, and a second powder feeding and spreading device 7. The scanning device is used to scan the molten powder material according to a predetermined path and process parameters. The upper surface of the base plate provides a working area 15 for supporting the powder material and the molten workpiece. The control device is used to control the scanning device and the two sets of powder feeding and spreading devices to scan, melt, and spread the powder in the sub-working area according to a predetermined logic. In the laser powder bed fusion additive manufacturing process, the control device refers to a control unit such as an industrial computer, a PLC, or a galvanometer control card.

[0133] In this embodiment, the multiple sets of powder feeding and spreading devices include a first powder feeding and spreading device 3 and a second powder feeding and spreading device 7, and there is an overlapping area 16 in the powder spreading range of the first powder feeding and spreading device 3 and the second powder feeding and spreading device 7; there is interference between the first powder feeding and spreading device 3 and the second powder feeding and spreading device 7, and the interference method is not limited to one set of powder feeding and spreading devices causing the scanning and melting action of some positions in the powder spreading range of the other set of powder feeding and spreading devices to be physically blocked or the powder layer thickness of some positions to change when the powder feeding and spreading device moves or spreads powder; therefore, in addition to the overlapping area 16, within the powder spreading range of the first powder feeding and spreading device 3, there is also an area interfered by the second powder feeding and spreading device 7 (referred to as the first interference area 17 for short), and in addition to the overlapping area 16, there is also an area interfered by the second powder feeding and spreading device 7 within the powder spreading range of the second powder feeding and spreading device 7 The area where the powder feeding and spreading device 3 interferes (referred to as the second interference area 18 for short); therefore, according to the interference between the first powder feeding and spreading device 3 and the second powder feeding and spreading device 7, the working area 15 is divided into four sub-working areas, namely area A1, area A2, area B1, and area B2; the area A1 is the area within the powder spreading range of the first powder feeding and spreading device 3 excluding the overlapping area 16 and the first interference area 17; the area A2 includes the first interference area 17 and part of the overlapping area 16; the area B1 is the area within the powder spreading range of the second powder feeding and spreading device 7 excluding the overlapping area 16 and the second interference area 18; the area B2 includes the second interference area 18 and the remaining part of the overlapping area 16. Finally, the working area 15 is divided into area A1, area A2, area B1, and area B2 as shown in Figure 7. This division is closely related to the subsequent additive manufacturing method. By optimizing the scanning, melting, and powder spreading order of each area, the waiting time for the scanning and melting action to the powder spreading action in the conventional additive manufacturing method can be avoided, thereby improving printing efficiency.

[0134] The control device controls the scanning device to scan part of the sub-working area in the working area 15, and at the same time controls the powder feeding and spreading device to spread powder on another part of the sub-working area, so that the powder spreading work and the scanning and melting work can be carried out independently at the same time, that is, the scanning and melting process of the scanning device is no longer interrupted by the powder spreading action of the powder feeding and spreading device, and can continue to work uninterruptedly, thereby maximizing the powder melting deposition efficiency, that is, the printing efficiency of the additive manufacturing equipment.

[0135] Optionally, the powder spreading ranges of the first powder feeding and spreading device 3 and the second powder feeding and spreading device 7 are the same size, and the center line of the overlapping area 16 is used as the dividing line between the A2 area and the B2 area, thereby allowing the first powder feeding and spreading device 3 and the second powder feeding and spreading device 7 to use the same mechanical structure, thereby facilitating equipment manufacturing and facilitating the even distribution of scanning melting tasks.

[0136] The control device is used to control the scanning device and two sets of powder feeding and spreading devices to realize scanning, melting and powder spreading of the A1 area, A2 area, B1 area and B2 area according to a predetermined logic.

[0137] Example 4:

[0138] Since there is an overlapping area 16 in the powder spreading areas of the two sets of powder feeding and spreading devices, there may be a motion interference problem between the two sets of powder feeding and spreading devices. In order to solve this problem, the additive manufacturing equipment of this embodiment can also additionally include two sets of translational motion mechanisms 19, as shown in Figure 7. The two sets of translational motion mechanisms 19 provide the first powder feeding and spreading device 3 and the second powder feeding and spreading device 7 with at least the function of translational motion in the vertical direction along their powder spreading directions. The specific implementation of the translational motion mechanism 19 can be in various forms such as ball screws, linear motors, gear racks, synchronous belts, crank sliders, etc., which are not limited here. In Figure 7, when the second powder feeding and spreading device 7 needs to move from left to right, the first powder feeding and spreading device 3 can move a distance upward in the figure with the help of the translational motion mechanism 19, so as to avoid interfering with the left and right movement of the second powder feeding and spreading device 7. Similarly, when the two sets of powder feeding and spreading devices move to the right side of the substrate in sequence, when the first powder feeding and spreading device 3 needs to move from right to left, the second powder feeding and spreading device 7 can move a certain distance downward in the figure with the help of the translational motion mechanism 19, thereby avoiding interfering with the left and right movement of the first powder feeding and spreading device 3.

[0139] Embodiment 5:

[0140] Because the powder spreading areas of the two powder feeding and spreading devices overlap 16, there may be motion interference between the two devices. To address this issue, the additive manufacturing apparatus of this embodiment may also include two additional rotary motion mechanisms 20, as shown in FIG8 . These two rotary motion mechanisms 20 provide the first and second powder feeding and spreading devices 3 and 7 with at least rotational motion normal to the surface of their working areas 15. The rotary motion mechanisms 20 can be implemented in various forms, such as rack and pinion gears, pulleys, slider cranks, and crank rockers, and are not limited here. In FIG8 , when the second powder feeding and spreading device 7 needs to move from left to right, the first powder feeding and spreading device 3 can rotate counterclockwise by a certain angle using the rotary motion mechanism 20 to avoid interfering with the left-right motion of the second powder feeding and spreading device 7. Similarly, when the two powder feeding and spreading devices move sequentially to the right side of the substrate, if the first powder feeding and spreading device 3 needs to move from right to left, the second powder feeding and spreading device 7 can rotate counterclockwise by a certain angle using the rotary motion mechanism 20 to avoid interfering with the left-right motion of the first powder feeding and spreading device 3.

[0141] Example 6:

[0142] The additive manufacturing method with a dual powder feeding and spreading device provided in this embodiment includes the general process of the powder bed melting additive manufacturing process, that is, for an additive manufacturing task, the geometric model of the workpiece to be manufactured is sliced ​​and layered according to the specified layer thickness to obtain the geometric contour and scanning path information of each layer, and then the powder is spread layer by layer and scanned and melted on the substrate according to the scanning path information of each layer, and finally all the workpiece entities are constructed; but it also has a special process for coordinating with the dual powder feeding and spreading device, and this special process is mainly reflected in the layer-by-layer powder spreading and scanning and melting process. First, as shown in Figure 7, the working area 15 on the surface of the substrate is divided into area A1, area A2, area B1, and area B2. Then, as shown in Figure 10, the steps of layer-by-layer powder spreading and scanning and melting are as follows:

[0143] ① Before starting additive manufacturing, the two sets of powder feeding and spreading devices are located in the initial position, at which the powder feeding and spreading devices are loaded with a certain amount of powder material for the subsequent powder spreading action. At this time, powder has not yet been spread on the substrate. In this embodiment, the initial position of the two sets of powder feeding and spreading devices is on the left side of the substrate, and both adopt a one-way powder spreading scheme, spreading powder during the movement from left to right, and not spreading powder from right to left. However, those skilled in the art should understand that the initial positions of the two sets of powder feeding and spreading devices can be changed to the right side of the substrate or to the left and right of the substrate, or a powder spreading scheme from right to left or a two-way powder spreading scheme can be adopted, and such changes are still within the scope of protection of the claims described in this application.

[0144] ② The first powder feeding and spreading device 3 moves from left to right, and spreads the powder in areas A1 and A2 according to the specified layer thickness, thereby preparing for the scanning and melting of the first layer of slices. The areas where the powder has been spread are marked with dot patterns in the figure. It is worth noting that whether or not the powder of the specified layer thickness is laid in areas B1 and B2 at this time does not affect the subsequent steps, because if the powder has been laid here, although it is subsequently spread with powder, considering that the substrate has not dropped, the total powder spread twice is only one layer of powder. In addition, the additive manufacturing equipment in this embodiment is not equipped with the motion mechanism described in claim 24, so the motion interference problem of the two sets of powder feeding and spreading devices will be solved by coordinating the movement of the two sets in the powder spreading direction or in the opposite direction. In this step of this embodiment, when the first powder feeding and spreading device 3 has spread the powder and moved to the right side of the substrate, it should further move a distance in the powder spreading direction, thereby reserving a parking position for the second powder feeding and spreading device 7 on the right side of the substrate to avoid motion interference.

[0145] ③ The control device directs the scanning device to perform scan melting of the current layer in area A2. The area where scan melting has completed is marked with a diagonal pattern in the figure. This area is scanned and melted first because the subsequent left-right movement of the second powder feeding and spreading device 7 will force the scan melting task in this area to pause and wait due to factors such as powder movement, localized powder layer thickness variations, and spatial interference. Prioritizing scan melting in this area avoids this waiting time.

[0146] ④ The control device controls the scanning device to perform scanning and melting of the current layer on the A1 area, and controls the second powder feeding and spreading device 7 to perform powder spreading of the current layer on the B1 area and the B2 area. In this step, the scanning and melting tasks and the powder spreading tasks are performed on different areas, and therefore can be performed simultaneously. In the case where the total cross-sectional area of ​​the layer of the workpiece to be manufactured is large, the powder spreading time is generally less than the scanning and melting time, so the powder spreading action will not cause the total additive manufacturing time to be extended, thereby improving the equipment efficiency. It is worth noting that after the second powder feeding and spreading device 7 moves from left to right and completes the powder spreading, it moves in the opposite direction of the powder spreading direction, that is, from right to left, and returns to its initial position. This action is to avoid the first powder feeding and spreading device 3 being blocked and interfered with by the second powder feeding and spreading device 7 when it moves from right to left in the subsequent steps. Furthermore, area A2 has already been scanned and melted in the previous step. At this point, although the second powder feeding and spreading device 7 spreads powder from left to right and its spreading range also covers part of area A2, since the substrate has not descended relative to the powder feeding and spreading device, area A2 generally does not add powder. Even if some powder is added to its surface, it will not affect subsequent steps. Furthermore, when the second powder feeding and spreading device 7 moves, it may cause friction with the workpiece formed by scanning and melting in area A2, causing the workpiece to deviate from its normal position and other negative effects. To reduce or avoid such effects, the contact area between the powder feeding and spreading device and the working area 15 can use a flexible structure, such as flexible rubber or a flexible brush, or even a contactless powder spreading method. Alternatively, a scraper structure as shown in FIG12 can be used, wherein the bottom surface of the scraper is formed by two parallel planes with a certain height difference, with the higher plane located above area A2 and the lower plane located above areas B1 and B2. This avoids friction between the scraper bottom surface and the workpiece formed by scanning and melting in area A2.

[0147] ⑤ The control device controls the substrate to descend to a specified layer thickness relative to the powder feeding and spreading device, and controls the scanning device to perform scanning and melting of the current layer on the B2 area. Since the thickness of a powder layer in the laser powder bed additive manufacturing process is on the order of 10-100μm, which is much smaller than the distance from the laser light outlet of the scanning device to the powder surface and smaller than the Rayleigh length of the laser, scanning and melting while the substrate is descending will not have a significant impact on the printing quality of the part. Therefore, in this step, the scanning and melting action can be started after the substrate is lowered, or during the substrate's descent, or before the substrate is lowered. There is no mandatory requirement for the order between the scanning and melting action and the substrate lowering action.

[0148] ⑥ The control device controls the scanning device to perform scanning and melting of the current layer on the B1 area, and controls the first powder feeding and spreading device 3 to perform powder spreading of the next layer on the A1 area and the A2 area. When the scanning and melting of the B1 area is completed, all working areas 15 of the current layer have been scanned and melted, which means that the scanning and melting work of the slice of this layer is completed. In this step, the scanning and melting tasks and the powder spreading tasks are performed on different areas, so they can be carried out simultaneously, thereby improving the efficiency of the equipment. It is worth noting that since this embodiment adopts a one-way powder spreading scheme, the first powder feeding and spreading device 3 first moves from right to left to return to the initial position, and then moves from left to right to spread powder. Those skilled in the art should understand that when a two-way powder spreading scheme is adopted, the first powder feeding and spreading device 3 can complete the powder spreading process while moving from right to left, but should still continue to move from left to right, so as to avoid interference with the second powder feeding and spreading device 7 during the subsequent movement. In addition, if the scanning and melting in step ⑤ has been completed and the substrate lowering action is still in progress, the scanning and melting action in this step ⑥ can still start immediately without waiting, which can further save time and improve printing efficiency.

[0149] ⑦ After the scanning, melting and powder spreading of the previous step are completed, the number of layers that have been scanned is increased by one, and the next layer becomes the current layer. At this time, the powder spreading state on the substrate returns to the state before the start of step ③.

[0150] ⑧ Repeat the above steps ③-⑦ until all layers of the workpiece to be manufactured are scanned and melted.

[0151] Embodiment seven:

[0152] The additive manufacturing method with a dual powder feeding and spreading device provided in this embodiment can further optimize the division of sub-working areas based on the aforementioned division, with the boundaries of adjacent sub-working areas changing layer by layer as the manufacturing process requires. As shown in Figure 11, in the current layer, a workpiece cross-section 21 to be scanned and melted exists adjacent to regions A1 and A2. If regions A1 and A2 are divided according to the straight line boundary shown in Figure 7, then the workpiece cross-section 21 will be divided into two halves, one half in region A1 and the other half in region A2. When the layer-by-layer powder spreading and scanning and melting steps of Example 4 are implemented, the scanning and melting of regions A1 and A2 are performed separately, resulting in the scanning and melting of workpiece cross-section 21 also being divided into two sections, which may lead to problems with printing quality and workpiece dimensional accuracy. Therefore, when scanning and melting the current layer, the boundaries of region A2 can be appropriately expanded, as shown in Figure 11, so that region A2 completely encompasses the workpiece cross-section 21. This ensures that the scan vector in the slice file of workpiece cross-section 21 is not split in half, and the scanning and melting is not interrupted. Similarly, for the boundaries between the B2 area and the A2 area, and the boundaries between the B1 area and the B2 area, the local position of the boundary can also be appropriately changed according to the position and shape of the workpiece section to be scanned and melted, so as to avoid scanning and melting the same workpiece section twice. The beneficial effect of the above approach is: avoiding scanning and melting the same workpiece section 21 twice, thereby avoiding possible printing quality problems and dimensional accuracy problems such as porosity and remelting, and further improving the forming quality of the workpiece to be manufactured. It should be further explained that in the expressions such as "the control device controls...scanning and melting, and simultaneously controls...powder spreading" in this application, the word "simultaneously" does not mean that the two actions are strictly synchronized in the starting time, but means that the two actions can be performed independently and there is no strict order requirement in the starting time of the actions. It is only necessary to achieve the beneficial effect of saving waiting time.

[0153] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0154] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. An additive manufacturing device with a multi-feed powder spreading device, characterized in that: It includes a scanning device, a control device, a base plate and multiple sets of powder feeding and spreading devices; the scanning device is used to scan the molten powder material according to a predetermined path and process parameters; the base plate is used to carry the powder material and the workpiece formed by the molten material, and the upper surface of the base plate is used for spreading the powder and scanning the molten workpiece. The entire working area is divided into multiple sub-working areas; the control device is used to control the scanning device to scan and melt some of the sub-working areas among all the sub-working areas, and at the same time control the powder feeding and spreading device to spread powder on other sub-working areas.

2. An additive manufacturing device with a multi-feed powder spreading device, characterized in that: It includes a scanning device, a control device, a substrate and multiple sets of powder feeding and spreading devices; the scanning device is used to scan the molten powder material according to a predetermined path and process parameters; the substrate is used to carry the powder material and the workpiece formed by melting, and the entire working area on the substrate used for spreading powder and scanning the melting is divided into multiple sub-working areas, including at least a first sub-working area and a second sub-working area; each set of powder feeding and spreading devices corresponds to a different sub-working area, and is used to spread the powder to the sub-working area; the multiple sets of powder feeding and spreading devices include at least a first powder feeding and spreading device and a second powder feeding and spreading device, the first powder feeding and spreading device is used to spread the powder to the first sub-working area on the substrate, and the second powder feeding and spreading device is used to spread the powder to the second sub-working area on the substrate.

3. The additive manufacturing equipment with a multi-feeding powder spreading device according to claim 2, characterized in that: The control device is used to control the scanning device to scan and melt some of the sub-working areas of all the sub-working areas, and at the same time control the powder feeding and spreading device to spread powder on other sub-working areas.

4. The additive manufacturing equipment with a multi-feeding powder spreading device according to claim 2, characterized in that: The shortest distance between the first sub-working area and the second sub-working area is less than or equal to 5 mm.

5. The additive manufacturing equipment with a multi-feeding powder spreading device according to claim 2, characterized in that: The multiple sub-working areas of the working area do not overlap with each other.

6. The additive manufacturing equipment with a multi-feeding powder spreading device according to claim 5, characterized in that: The powder spreading directions of the multiple sets of powder feeding and spreading devices are the same or opposite, and the working area is divided into multiple non-overlapping sub-working areas along the direction perpendicular to the powder spreading direction.

7. The additive manufacturing equipment with a multi-feeding powder spreading device according to claim 2, characterized in that: Each set of powder delivery and spreading device includes an arm seat, a scraper seat and two scrapers. The scraper seat is arranged on the arm seat. A powder receiving groove is provided in the scraper seat. The two scrapers are respectively arranged on both sides of the bottom of the powder receiving groove, so that the powder falls into the working area through the powder receiving groove and is flattened to the corresponding sub-working area under the action of the scraper on one side.

8. The additive manufacturing equipment with a multi-feeding powder spreading device according to claim 7, characterized in that: The outer sides of the scraper seat away from the arm seat are arc-shaped; the outer sides of the arm seat away from the scraper seat are arc-shaped.

9. The additive manufacturing equipment with a multi-powder feeding and spreading device according to claim 7 or 8, characterized in that: The additive manufacturing equipment also includes a drive system, a transmission system, a linear guide rail and a slider. The guide rail is arranged on a large working plate. The arm seat is connected to the drive system through a transmission system. Each arm seat is arranged on a corresponding slider so that under the drive of the drive system, the arm seat and the slider move parallel to the linear guide rail.

10. An additive manufacturing method using the additive manufacturing equipment with multiple powder feeding and spreading devices according to any one of claims 2 to 9, characterized in that: The geometric model of the workpiece to be manufactured is sliced ​​layer by layer according to the specified layer thickness to obtain the geometric contour and scanning path information of each layer. Then, powder is spread layer by layer and scan-melted on the substrate according to the scanning path information of each layer, and finally all the workpiece entities are constructed; the layer-by-layer powder spreading and scanning-melting include at least the following steps: Step S1: The control device controls the scanning device to scan and melt the current layer in the first sub-working area, and controls the second powder feeding and spreading device to spread the current layer in the second sub-working area; Step S2: After scanning and melting are completed in the first sub-working area and powder spreading is completed in the second sub-working area, the control device controls the substrate to descend relative to the powder feeding and spreading device to a height of a specified layer thickness; Step S3: The control device controls the scanning device to scan and melt the current layer in the second sub-working area, and controls the first powder feeding and spreading device to spread the next layer in the first sub-working area. Step S4: After the scanning and melting of the second sub-working area is completed and the powder spreading of the first sub-working area is completed, the number of layers that have been scanned is increased by one, and the next layer becomes the current layer; Step S5: repeat the above steps S1 to S4 until all layers of the workpiece to be manufactured and formed are scanned and melted.

11. The additive manufacturing method according to claim 10, characterized in that: The scanning melting action of step S3 is started after the substrate lowering action in step S2 is completed, or during the substrate lowering process, or before the substrate lowering action.

12. The additive manufacturing method according to claim 10, characterized in that: Before scanning and melting the first layer, use the first powder feeding and spreading device to spread the first layer of powder in the first sub-working area and the second sub-working area on the substrate respectively, or only use the first powder feeding and spreading device to spread the first layer of powder in the first sub-working area on the substrate.

13. The additive manufacturing method according to any one of claims 10 to 12, characterized in that: The powder spreading is performed and completed by the powder spreading device in the reciprocating motion relative to the substrate surface, where one motion direction in the reciprocating motion is defined as the positive direction, and the other motion direction is defined as the reverse direction; the powder spreading device only performs and completes one layer of powder spreading during the positive direction motion, or only performs and completes one layer of powder spreading during the reverse direction motion, or performs and completes one layer of powder spreading during the positive direction motion and the reverse direction motion respectively.

14. An additive manufacturing device with a multi-feed powder spreading device, characterized in that: It at least includes a scanning device, a control device, a base plate and multiple sets of powder feeding and spreading devices; the scanning device is used to scan the molten powder material according to a predetermined path and process parameters; the upper surface of the base plate provides a working area for carrying the powder material and the workpiece formed by melting, and each set of powder feeding and spreading devices is used to spread the powder material according to a specified layer thickness to the corresponding powder spreading range in the working area, and there is an overlapping area between the powder spreading ranges of adjacent powder feeding and spreading devices, and the sum of the powder spreading ranges of all powder feeding and spreading devices at least covers the entire working area; the working area is divided into multiple sub-working areas, so that the control device is used to control the scanning device and the multiple sets of powder feeding and spreading devices to realize the scanning, melting and powder spreading of the sub-working areas according to a predetermined logic.

15. The additive manufacturing equipment with a multi-feeding powder spreading device according to claim 14, characterized in that: The control device controls the scanning device to scan and melt part of the sub-working areas in the working area, and controls the powder feeding and spreading device to spread powder on another part of the sub-working areas.

16. The additive manufacturing equipment with a multi-powder feeding and spreading device according to claim 14, characterized in that: The sub-working areas are arranged perpendicular to the powder spreading direction.

17. The additive manufacturing equipment with a multi-powder feeding and spreading device according to any one of claims 14 to 16, characterized in that: The multiple sets of powder feeding and spreading devices include a first powder feeding and spreading device and a second powder feeding and spreading device, and there is an overlapping area in the powder spreading ranges of the first powder feeding and spreading device and the second powder feeding and spreading device; the working area is divided into four sub-working areas, namely A1 area, A2 area, B1 area, and B2 area; the A1 area is the area within the powder spreading range of the first powder feeding and spreading device except the overlapping area and is not interfered with by the second powder feeding and spreading device; the A2 area includes the area within the powder spreading range of the first powder feeding and spreading device except the overlapping area and is interfered with by the second powder feeding and spreading device, as well as a part of the overlapping area; the B1 area is the area within the powder spreading range of the second powder feeding and spreading device except the overlapping area and is not interfered with by the first powder feeding and spreading device; the B2 area includes the area within the powder spreading range of the second powder feeding and spreading device except the overlapping area and is interfered with by the first powder feeding and spreading device, as well as the remaining part of the overlapping area; the control device is used to control the scanning device and the two sets of powder feeding and spreading devices to realize scanning, melting and powder spreading of the A1 area, A2 area, B1 area, and B2 area according to a predetermined logic.

18. The additive manufacturing equipment with a multi-powder feeding and spreading device according to claim 17, characterized in that: The powder spreading ranges of the first powder feeding and spreading devices are the same in size, and the center line of the overlapping area is used as the boundary line between the A2 area and the B2 area.

19. The additive manufacturing equipment with a multi-feeding powder spreading device according to claim 17, characterized in that: It also includes a motion mechanism for providing the first powder feeding and spreading device and the second powder feeding and spreading device with at least the motion function of translation in the vertical direction along their powder spreading direction; or for providing the first powder feeding and spreading device and the second powder feeding and spreading device with at least the motion function of rotation around the normal surface of their working area.

20. An additive manufacturing method using the additive manufacturing equipment with multiple powder feeding and spreading devices according to any one of claims 17 to 19, characterized in that: The geometric model of the workpiece to be manufactured is sliced ​​layer by layer according to the specified layer thickness to obtain the geometric contour and scanning path information of each layer. Then, powder is spread layer by layer and scan-melted on the substrate according to the scanning path information of each layer, and finally all the workpiece entities are constructed; the layer-by-layer powder spreading and scanning-melting at least include the following steps: Step S1: The control device controls the scanning device to perform scanning and melting of the current layer on the A2 area; Step S2: The control device controls the scanning device to perform scanning and melting of the current layer on the A1 area, and controls the second powder feeding and spreading device to perform powder spreading of the current layer on the B1 and B2 areas; Step S3: The control device controls the substrate to descend relative to the powder feeding device to a height of a specified layer thickness, and controls the scanning device to perform scanning and melting of the current layer in the B2 area; Step S4: The control device controls the scanning device to perform scanning and melting of the current layer on the B1 area, and controls the first powder feeding and spreading device to perform powder spreading of the next layer on the A1 and A2 areas. Step S5: After the scanning, melting and powder spreading of the previous step are completed, the number of layers that have completed scanning and melting is increased by one, and the next layer becomes the current layer; Step S6: Repeat steps S1-S5 until all layers of the workpiece to be manufactured are scanned and melted.

21. The additive manufacturing method according to claim 20, characterized in that: The scanning melting action in step S3 is started after the substrate is lowered, or during the substrate lowering process, or before the substrate is lowered.

22. The additive manufacturing method according to claim 20, wherein: If the scanning melting operation in step S3 is completed while the substrate lowering operation is still in progress, the scanning melting operation in step S4 starts immediately or waits until the substrate lowering operation is completed before starting again.

23. The additive manufacturing method according to claim 20, wherein: When the substrate descends relative to the powder feeding and spreading device in step S3, the scanning device scanning the B2 area and the B1 area descends synchronously or dynamically zooms to keep the distance between the heat source focus and the molten powder to be scanned unchanged.

24. The additive manufacturing method according to claim 20, characterized in that The powder spreading is executed and completed by the powder spreading device in the reciprocating motion relative to the working area, and one motion direction in the reciprocating motion is defined as the positive direction, and the other motion direction is defined as the reverse direction; the powder spreading device only executes and completes one layer of powder spreading during the forward motion, or only executes and completes one layer of powder spreading during the reverse motion, or executes and completes one layer of powder spreading during the forward and reverse motions respectively.

25. The additive manufacturing method according to claim 20, wherein: When one of the two powder spreading devices is performing the powder spreading work, the other powder spreading device takes the following actions in advance to avoid motion interference: through the motion mechanism, it makes itself translate at least in the direction perpendicular to the powder spreading direction, or through the motion mechanism, it makes itself rotate at least around the normal direction of the working area surface, or continues to move in the powder spreading direction or in the opposite direction after completing its last powder spreading action.

26. The additive manufacturing method according to claim 20, wherein: The boundaries of adjacent sub-working areas change layer by layer according to the manufacturing process requirements.

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