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

Abstract

The invention discloses additive manufacturing equipment with multiple powder feeding and spreading devices and an additive manufacturing method. The equipment at least comprises a scanning device, a control device, a substrate and the multiple powder feeding and spreading devices. The scanning device scans the molten powder material according to a preset path and process parameters; a working area is provided on the upper surface of the base plate and used for bearing powder materials and workpieces formed by melting, each set of powder feeding and laying device enables the powder materials to be laid in the corresponding powder laying range in the working area according to the specified layer thickness, and the powder laying ranges of the adjacent powder feeding and laying devices are overlapped. The sum of the powder spreading ranges of all the powder feeding and spreading devices covers the whole working area; and the working area is divided into a plurality of sub-working areas, so that the scanning device and the multiple sets of powder feeding and laying devices achieve scanning melting and powder laying of the sub-working areas according to preset logic. The powder spreading work and the scanning work can be simultaneously and independently carried out, namely the powder spreading time does not occupy the scanning time of the equipment, so that the printing effect of the equipment can be furthest improved.

Description

Technical Field

[0001] 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

[0002] Powder bed additive manufacturing technology is a rapid manufacturing technology that uses a scanning device to control the heat source to scan the melted powder material layer by layer, and stack layers to form a three-dimensional entity. The process flow is as follows: first, the three-dimensional model of the workpiece is sliced ​​layer by layer to obtain a slice file, which contains the cross-sectional geometry information of each layer of the workpiece, the heat source scanning path information and other process parameter information; a layer of powder material is evenly spread on the surface of the substrate, and the scanning device selectively melts the powder according to the slice file of the first layer to form a layer of workpiece entity; another layer of powder material is evenly spread on the upper surface of the layer of powder and the workpiece entity, and the scanning device continues to scan according to the slice file of the next layer to selectively melt the powder, and so on layer by layer to finally obtain a three-dimensional entity.

[0003] 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 spreading of the current layer of powder before starting to selectively scan the molten powder. This waiting time causes the scanning device to be unable to continuously scan the molten powder without interruption, reducing the printing efficiency of the additive manufacturing equipment. In general applications, the time waiting for the completion of powder spreading accounts for 10%-30% of the additive manufacturing time. Therefore, improving the powder spreading device and optimizing the coordination logic of scanning the molten powder and spreading the powder are particularly important for improving the printing efficiency of additive manufacturing equipment. Summary of the invention

[0004] In order to solve the above-mentioned problems existing in the prior art, the present invention provides an additive manufacturing device and an additive manufacturing method with multiple powder feeding and spreading devices, in which the powder spreading work and the scanning and melting work can be performed 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 device.

[0005] In order to achieve the above-mentioned objectives, the present invention provides an additive manufacturing device with multiple powder feeding and spreading devices, which at least 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 upper surface of the substrate 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 to a corresponding powder spreading range in the working area according to a specified layer thickness, and there are overlapping areas in 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 scanning, melting and powder spreading of the sub-working areas according to a predetermined logic.

[0006] As a further preferred embodiment of the present invention, the control device controls the scanning device to scan and melt a 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.

[0007] As a further preferred embodiment of the present invention, the sub-working areas are arranged perpendicular to the powder spreading direction.

[0008] As a further preferred embodiment of the present invention, 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, and 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, and 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.

[0009] As a further preferred embodiment of the present invention, the powder spreading ranges of the first powder feeding and spreading device are the same in size, and the center line of the overlapping area is used as the boundary between the A2 area and the B2 area.

[0010] As a further preferred embodiment of the present invention, 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.

[0011] The present invention also provides an additive manufacturing method of an additive manufacturing device with a multi-feed powder spreading device, which slices the geometric model of the workpiece to be manufactured in layers according to the specified layer thickness to obtain the geometric contour and scanning path information of each layer, and then spreads the powder layer by layer and scans and melts on the substrate according to the scanning path information of each layer, and finally constructs all the workpiece entities; the layer-by-layer powder spreading and scanning and melting at least include the following steps:

[0012] Step S1, the control device controls the scanning device to perform scanning and melting of the current layer on the A2 area;

[0013] 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;

[0014] 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 on the B2 area;

[0015] 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;

[0016] 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.

[0017] Step S6, repeating steps S1-S5 until all layers of the workpiece to be manufactured are scanned and melted;

[0018] As a further preferred embodiment of the present invention, the scanning melting action in step S3 is performed after the substrate descends, or during the substrate descends, or before the substrate descends.

[0019] As a further preferred embodiment of the present invention, if the scanning melting in step S3 is 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.

[0020] As a further preferred embodiment of the present invention, when the substrate descends relative to the powder feeding device in step S3, the scanning device for 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.

[0021] As a further preferred embodiment of the present invention, the powder spreading is performed and completed by the powder spreading device in a reciprocating motion relative to the working area, one direction of motion in the reciprocating motion is defined as a positive direction, and the other direction of motion is defined as a 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, or performs and completes one layer of powder spreading during the forward and reverse motions respectively.

[0022] As a further preferred embodiment of the present invention, when one of the two powder delivering and spreading devices is performing the powder spreading work, the other set of powder delivering and spreading device takes the following actions in advance to avoid motion interference: through the motion mechanism, it translates itself at least in the direction perpendicular to the powder spreading direction, or through the motion mechanism, it rotates itself 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 its last powder spreading action is completed.

[0023] As a further preferred solution of the present invention, the boundaries of adjacent sub-working areas vary layer by layer as required by the manufacturing process.

[0024] The additive manufacturing equipment and additive manufacturing method with a multi-feeding powder spreading device of the present invention, by adopting the above technical solution, have the following beneficial effects:

[0025] 1. In the present invention, multiple sets of powder feeding and spreading devices are included, 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 according to the specified layer thickness, and the powder spreading ranges of adjacent powder feeding and spreading devices have overlapping areas; thus, 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 work continuously without interruption, thereby maximizing the powder melting deposition efficiency, that is, the printing efficiency of the additive manufacturing equipment;

[0026] 2. In the present invention, the working area on the surface of the substrate used for spreading powder can be fully used for scanning and melting, and there is no area that cannot be used for scanning and melting due to interference in 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.

[0027] 3. The multi-feed powder-spreading device of the present invention is a technical upgrade of the original additive manufacturing equipment equipped with a single-feed powder-spreading device, and the printing efficiency is significantly improved.

[0028] 4. The additive manufacturing equipment with a multi-feed powder spreading device of the present invention is compatible with one-way powder spreading and two-way powder spreading functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1A schematic diagram of the structure of an additive manufacturing device according to the first embodiment of the present invention;

[0030] Figure 2 A schematic diagram of the division of working areas in the first embodiment of the present invention;

[0031] Figure 3 A schematic diagram of the structure of the powder feeding and spreading device in the second embodiment provided by the present invention using a translational motion mechanism to avoid interference;

[0032] Figure 4 A schematic diagram of the structure of the powder feeding and spreading device in the third embodiment provided by the present invention using a rotary motion mechanism to avoid interference;

[0033] Figure 5 A flowchart of the additive manufacturing method according to the fourth embodiment of the present invention;

[0034] Figure 6 A schematic diagram of the dynamic division of working areas in the fifth embodiment provided by the present invention;

[0035] Figure 7 A schematic structural diagram of a powder feeding and spreading device of an embodiment of an additive manufacturing device with multiple powder feeding and spreading devices provided by the present invention;

[0036] Figure 8 A schematic structural diagram of a scraper of a powder feeding and spreading device of an embodiment of an additive manufacturing device with multiple powder feeding and spreading devices provided by the present invention.

[0037] Markings in the figure:

[0038] 1. First powder feeding and spreading device; 2. Second powder feeding and spreading device; 3. Working area; 4. Overlapping area; 5. First interference area; 6. Second interference area; 7. Translational motion mechanism; 8. Rotational motion mechanism; 9. Workpiece profile; 10. Screws; 11. Arm seat; 12. Scraper seat; 13. Powder receiving trough; 14. Scraper; 15. Press plate. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0040] like Figure 1As shown, the additive manufacturing equipment with multiple powder feeding and spreading devices of the present invention comprises at least 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 upper surface of the substrate provides a working area 3 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 3 according to the specified layer thickness, and the powder spreading ranges of adjacent powder feeding and spreading devices have overlapping areas 4, and the sum of the powder spreading ranges of all powder feeding and spreading devices at least covers the entire working area 3; the working area 3 is divided into multiple sub-working areas, so that the control device is used to control the scanning device and multiple sets of powder feeding and spreading devices to realize 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.

[0041] In a specific implementation, the plurality of sub-working areas are arranged perpendicular to the powder spreading direction. Preferably, the control device controls the scanning device to scan part of the sub-working areas in the working area 3, and controls the powder feeding and spreading device to spread powder on another part of the sub-working areas, so that the powder spreading work and the scanning and melting work are performed 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 work continuously without interruption, thereby maximizing the powder melting deposition efficiency, that is, the printing efficiency of the additive manufacturing equipment.

[0042] As an embodiment of the present application, the multiple sets of powder feeding and spreading devices include a first powder feeding and spreading device 1 and a second powder feeding and spreading device 2, and there is an overlapping area 4 in the powder spreading ranges of the first powder feeding and spreading device 1 and the second powder feeding and spreading device 2; there is interference between the first powder feeding and spreading device 1 and the second powder feeding and spreading device 2, and the interference method is not limited to that when one set of powder feeding and spreading devices moves or spreads powder, the scanning and melting action of some positions within the powder spreading range of another set of powder feeding and spreading devices is physically blocked or the powder layer thickness at some positions changes; therefore, in addition to the overlapping area 4, there is also an area interfered by the second powder feeding and spreading device 2 (referred to as the first interference area 5) within the powder spreading range of the first powder feeding and spreading device 1, and in addition to the overlapping area In addition to the working area 4, there is also an area interfered by the first powder feeding device 1 (referred to as the second interference area 6); therefore, according to the interference between the first powder feeding device 1 and the second powder feeding device 2, the working area 3 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 1 except the overlapping area 4 and the first interference area 5; the area A2 includes the first interference area 5 and part of the overlapping area 4; the area B1 is the area within the powder spreading range of the second powder feeding device 2 except the overlapping area 4 and the second interference area 6; the area B2 includes the second interference area 6 and the remaining part of the overlapping area 4. Finally, the working area 3 is divided as follows: Figure 2 The A1 area, A2 area, B1 area, and B2 area are shown. 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 between the scanning and melting action and the powder spreading action in the conventional additive manufacturing method can be avoided, thereby improving the printing efficiency.

[0043] Preferably, the powder spreading ranges of the first powder feeding and spreading device 1 and the second powder feeding and spreading device 2 are the same in size, and the center line of the overlapping area 4 is used as the boundary between the A2 area and the B2 area, thereby allowing the first powder feeding and spreading device 1 and the second powder feeding and spreading device 2 to use the same mechanical structure, thereby facilitating equipment manufacturing and facilitating the even distribution of scanning melting tasks.

[0044] 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.

[0045] As a further preferred embodiment of the present invention, it also includes a motion mechanism, which is used to provide the first powder feeding and spreading device 1 and the second powder feeding and spreading device 2 with at least the motion function of translation in the vertical direction of their powder spreading direction; or to provide the first powder feeding and spreading device 1 and the second powder feeding and spreading device 2 with at least the motion function of normal rotation around the surface of their working area 3, 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 the 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 1 and the second powder feeding and spreading device 2 with translational motion, oblique motion, rotation and other motion functions, respectively, so as to avoid the motion interference between the two. Preferably, it is used to provide the first powder feeding and spreading device 1 and the second powder feeding and spreading device 2 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, respectively, so that the operation is simple and more labor-saving.

[0046] It is understandable 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 change layer by layer as required by the manufacturing process. For details, see Example 5 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, etc., according to the manufacturing process, so as to further avoid the formation of manufacturing defects on the boundary line.

[0047] 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.

[0048] In a specific implementation, Figure 7As shown, each set of powder delivery and spreading device includes an arm support 11, a scraper support 12 and two scrapers 14. The scraper support 12 is arranged on the arm support 11. A powder receiving groove 13 is arranged in the scraper support 12. The two scrapers 14 are respectively arranged on both sides of the bottom of the powder receiving groove 13, so that the powder falls into the working area 3 through the powder receiving groove 13, and is flattened to the corresponding sub-working area under the action of the scraper 14 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 arranged on the working plate. The arm support 11 is connected to the drive system through the transmission system. Each arm support 11 is arranged on the corresponding slider, so that the arm support 11 and the slider move parallelly 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, a master-slave pulley and a synchronous belt. The reducer is installed on the reducer fixing seat, and the synchronous belt is wound on the master-slave pulley. The reducer is driven by the servo motor and drives the arm seat 11 to translate through the synchronous belt, thereby driving the scraper 14 to move on the corresponding sub-working area to spread powder. Of course, in the specific implementation, the drive system and transmission system can also be other specific structures, which are not listed here one by one.

[0049] Preferably, see further Figure 7 The outer sides of the scraper seat 12 away from the arm seat 11 are arc-shaped; the outer sides of the arm seat 11 away from the scraper seat 12 are arc-shaped. This structural design can reduce the impact of wind field disturbance caused by the scraper 14 during movement on the normal printing of another sub-working area, thereby improving the printing quality.

[0050] In a specific implementation, the powder feeding device further includes two pressing plates 15 and two screws 10 , and each scraper 14 is fixed to the bottom of the scraper seat 12 by the pressing plate 15 and the screw 10 .

[0051] Preferably, the bottom surface of the scraper 14 is designed as two parallel planes with a certain height difference, see Figure 8 This height difference can prevent the bottom surface of the scraper from colliding with the workpiece or powder in the scanned molten area. For details, please refer to Example 4 below in this application.

[0052] It should be noted here that the above is a specific preferred structure of the powder delivery and spreading device. In specific implementation, it can also be other structures with powder delivery and spreading functions in the prior art, which will not be specifically elaborated in this application.

[0053] The present invention also provides an additive manufacturing method using the additive manufacturing device with a multi-feed powder spreading device as described in any of the above embodiments, which slices the geometric model of the workpiece to be manufactured in layers according to the 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 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:

[0054] Step S1, the control device controls the scanning device to perform scanning and melting of the current layer on the A2 area;

[0055] 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 2 to perform powder spreading of the current layer on the B1 and B2 areas;

[0056] 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 on the B2 area;

[0057] 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 1 to perform powder spreading of the next layer on the A1 and A2 areas;

[0058] 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.

[0059] Step S6, repeating steps S1-S5 until all layers of the workpiece to be manufactured are scanned and melted.

[0060] The scanning and melting action in the above step S3 can be performed after the substrate descends, or can be performed during the substrate descending process or before the substrate descends. Preferably, it is performed during the substrate descending process or before the substrate descends, which can further reduce the waiting time for scanning and melting and improve printing efficiency. The feasibility of this approach comes from the fact that in some types of additive manufacturing, such as laser powder bed melting additive manufacturing, the layer thickness of the descending substrate 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 obvious effect on the printing quality of the part.

[0061] 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. Preferably, 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.

[0062] 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.

[0063] It should be noted here that the above-mentioned powder feeding and spreading device performs and completes the powder spreading action in the reciprocating motion relative to the working area 3, and the above-mentioned layer-by-layer powder spreading and scanning melting process do not limit the powder feeding and spreading device to unidirectional powder spreading or bidirectional powder spreading. Specifically, one direction of movement in the reciprocating motion can be defined as the positive direction, and the other direction of movement can be defined as the reverse direction; the powder feeding and spreading device only performs and completes the spreading of one layer of powder during the forward direction movement, or only performs and completes the spreading of one layer of powder during the reverse direction movement, or performs and completes the spreading of one layer of powder during the forward direction movement and the reverse direction movement respectively.

[0064] Since the two sets of powder delivery and spreading devices have overlapping powder spreading areas, namely, overlapping area 4, there is a certain amount of motion interference between the two sets of powder delivery and spreading devices. Preferably, when the first powder delivery and spreading device 1 performs the powder spreading work, the second powder delivery and spreading device 2 takes the following actions in advance to avoid motion interference: the second powder delivery and spreading device 2 translates itself at least in a direction perpendicular to the powder spreading direction through a motion mechanism, or rotates itself at least in a normal direction around the surface of the working area 3 through a motion mechanism, or continues to move in the powder spreading direction or in the opposite direction after the last powder spreading action is completed.

[0065] 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.

[0066] It should be further explained that, in expressions such as "the control device controls...scanning and melting, and simultaneously controls...powder spreading" in the present invention, the word "simultaneously" does not mean that the two actions are strictly synchronized in start time, but means that the two actions can be performed independently and there is no strict requirement on the order of the start time of the actions. It is only necessary to achieve the beneficial effect of saving waiting time.

[0067] In order to enable those skilled in the art to better understand and implement the technical solution of the present invention, the technical solution of the present invention is described in detail below in the form of embodiments and drawings.

[0068] Embodiment 1:

[0069] like Figure 1As shown, the additive manufacturing equipment with multiple powder feeding and spreading devices of this embodiment includes a scanning device, a control device, a substrate, a first powder feeding and spreading device 1 and a second powder feeding and spreading device 2; the scanning device is used to scan the molten powder material according to a predetermined path and process parameters; the upper surface of the substrate provides a working area 3 for carrying powder materials and molten workpieces; 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 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, a galvanometer control card, etc.

[0070] In this embodiment, the multiple sets of powder feeding and spreading devices include a first powder feeding and spreading device 1 and a second powder feeding and spreading device 2, and there is an overlapping area 4 in the powder spreading ranges of the first powder feeding and spreading device 1 and the second powder feeding and spreading device 2; there is interference between the first powder feeding and spreading device 1 and the second powder feeding and spreading device 2, and the interference method is not limited to that when one set of powder feeding and spreading devices moves or spreads powder, the scanning and melting action of some positions within the powder spreading range of the other set of powder feeding and spreading devices is physically blocked or the powder layer thickness at some positions changes; therefore, in addition to the overlapping area 4, within the powder spreading range of the first powder feeding and spreading device 1, there is also an area interfered by the second powder feeding and spreading device 2 (referred to as the first interference area 5 for short), and in addition to the overlapping area 4, there is also an area within the powder spreading range of the second powder feeding and spreading device 2 In the area interfered by the first powder feeding device 1 (referred to as the second interference area 6); therefore, according to the interference between the first powder feeding device 1 and the second powder feeding device 2, the working area 3 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 1 except the overlapping area 4 and the first interference area 5; the area A2 includes the first interference area 5 and part of the overlapping area 4; the area B1 is the area within the powder spreading range of the second powder feeding device 2 except the overlapping area 4 and the second interference area 6; the area B2 includes the second interference area 6 and the remaining part of the overlapping area 4. Finally, the working area 3 is divided as follows: Figure 2 The A1 area, A2 area, B1 area, and B2 area are shown. 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 between the scanning and melting action and the powder spreading action in the conventional additive manufacturing method can be avoided, thereby improving the printing efficiency.

[0071] The control device controls the scanning device to scan part of the sub-working areas in the working area 3, and controls the powder feeding and spreading device to spread powder on another part of the sub-working areas, 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.

[0072] Preferably, the powder spreading ranges of the first powder feeding and spreading device 1 and the second powder feeding and spreading device 2 are the same in size, and the center line of the overlapping area 4 is used as the boundary between the A2 area and the B2 area, thereby allowing the first powder feeding and spreading device 1 and the second powder feeding and spreading device 2 to use the same mechanical structure, thereby facilitating equipment manufacturing and facilitating the even distribution of scanning melting tasks.

[0073] 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.

[0074] Embodiment 2:

[0075] Since the powder spreading areas of the two sets of powder feeding and spreading devices have an overlapping area 4, 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 device of this embodiment can also additionally include two sets of translational motion mechanisms 7, such as Figure 2 As shown. The two sets of translational motion mechanisms 7 provide the first powder feeding and spreading device 1 and the second powder feeding and spreading device 2 with at least a translational motion function in a vertical direction along the powder spreading direction. The specific implementation of the translational motion mechanism 7 can be in various forms such as a ball screw, a linear motor, a gear rack, a synchronous belt, a crank slider, etc., which are not limited here. Figure 2 In the figure, when the second powder feeding device 2 needs to move from left to right, the first powder feeding device 1 can move a distance upward in the figure with the help of the translation mechanism 7, so as to avoid interfering with the left and right movement of the second powder feeding device 2. Similarly, when the two sets of powder feeding devices move to the right side of the substrate in sequence, when the first powder feeding device 1 needs to move from right to left, the second powder feeding device 2 can move a distance downward in the figure with the help of the translation mechanism 7, so as to avoid interfering with the left and right movement of the first powder feeding device 1.

[0076] Embodiment three:

[0077] Since the powder spreading areas of the two sets of powder feeding and spreading devices have an overlapping area 4, 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 device of this embodiment can also include two additional sets of rotating motion mechanisms 8, such as Figure 3 As shown. The two sets of rotary motion mechanisms 8 provide the first powder feeding device 1 and the second powder feeding device 2 with at least a normal rotation function around the surface of their working area 3. The specific implementation of the rotary motion mechanism 8 can be in the form of a gear rack, a pulley, a crank slider, a crank rocker, etc., which is not limited here. Figure 3In the embodiment, when the second powder feeding device 2 needs to move from left to right, the first powder feeding device 1 can be rotated counterclockwise by a certain angle with the help of the rotary motion mechanism 8, so as to avoid interfering with the left and right movement of the second powder feeding device 2. Similarly, when the two sets of powder feeding devices move to the right side of the substrate in sequence, when the first powder feeding device 1 needs to move from right to left, the second powder feeding device 2 can be moved counterclockwise by a certain angle with the help of the rotary motion mechanism 8, so as to avoid interfering with the left and right movement of the first powder feeding device 1.

[0078] Embodiment 4:

[0079] The additive manufacturing method with a dual powder feeding and spreading device provided in this embodiment includes the general process of the powder bed fusion 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 and scanned and melted layer by layer 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 cooperating with the dual powder feeding and spreading device. This special process is mainly reflected in the layer-by-layer powder spreading and scanning and melting process. First, Figure 2 As shown, the working area 3 on the substrate surface is divided into area A1, area A2, area B1, and area B2. Figure 5 As shown, the steps of layer-by-layer powder spreading and scanning melting are as follows:

[0080] ① Before starting additive manufacturing, the two sets of powder delivery and spreading devices are located in the initial position, where a certain amount of powder material is loaded on the powder delivery and spreading devices for subsequent powder spreading actions, and at this time, powder has not yet been spread on the substrate. In this embodiment, the initial positions of the two sets of powder delivery and spreading devices are on the left side of the substrate, and both adopt a one-way powder spreading scheme, spreading powder during 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 delivery and spreading devices can be changed to the right side of the substrate or to the left and right of the substrate, and 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.

[0081] ② The first powder feeding and spreading device 1 moves from left to right, and spreads the powder in the A1 area and the A2 area according to the specified layer thickness, so as to prepare for the scanning and melting of the first layer of slices. The area where the powder has been spread is marked with a dot pattern in the figure. It is worth noting that whether the powder of the specified layer thickness is laid in the B1 area and the B2 area at this time does not affect the subsequent steps, because if the powder has been laid here, although it is spread again later, 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 6, 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 in the powder spreading direction or in the opposite direction. In this step of the present embodiment, when the first powder feeding and spreading device 1 has spread the powder and moved to the right side of the substrate, it should move a further distance in the powder spreading direction, so as to reserve a parking position for the second powder feeding and spreading device 2 on the right side of the substrate to avoid motion interference.

[0082] ③ The control device controls the scanning device to perform scanning and melting of the current layer on area A2. The area where scanning and melting is completed is marked with a diagonal pattern in the figure. The reason why this area is scanned and melted first is that the scanning and melting task of this area will be forced to pause and wait due to factors such as powder movement, local powder layer thickness changes, and spatial position interference during the subsequent second powder feeding and spreading device 2 moving left and right to spread powder. Prioritizing scanning and melting this area will avoid this waiting time.

[0083] 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 2 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 ​​this 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 extension of the total additive manufacturing time, thereby improving the equipment efficiency. It is worth noting that after the second powder feeding and spreading device 2 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 1 from being blocked and interfered by the second powder feeding and spreading device 2 when it moves from right to left in the subsequent steps. In addition, the A2 area has been scanned and melted in the previous step. At this time, although the second powder feeding and spreading device 2 spreads powder from left to right and its powder spreading range also covers part of the A2 area, since the substrate has not dropped relative to the powder feeding and spreading device, the A2 area generally will not add powder. Even if some powder is added to its surface, it will not affect the subsequent steps. In addition, when the second powder feeding and spreading device 2 moves, it may cause friction with the workpiece that has been scanned and melted in the A2 area, causing negative effects such as the workpiece deviating from its normal position. In order to reduce or avoid such effects, the contact part between the powder feeding and spreading device and the working area 3 can use a flexible structure, such as flexible rubber, flexible brush, or even a contactless powder spreading method. Preferably, it can also be used. Figure 8 The scraper structure shown has a bottom surface consisting of two parallel planes with a certain height difference. The higher plane is above the A2 area, and the lower plane is above the B1 area and the B2 area. This avoids friction between the bottom surface of the scraper and the workpiece formed by scanning the melt in the A2 area.

[0084] ⑤ The control device controls the substrate to descend to a specified layer thickness relative to the powder feeding device, and controls the scanning device to perform scanning and melting of the current layer on the B2 area. Since in the laser powder bed additive manufacturing process, the thickness of a powder layer 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 descends, or during the substrate descending process, or before the substrate descends, and there is no necessary order requirement between the scanning and melting action and the substrate descending action.

[0085] 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 1 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 3 of the current layer have been scanned and melted, which means that the scanning and melting work of the slices 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 performed simultaneously, thereby improving the efficiency of the equipment. It is worth noting that since the present embodiment adopts a one-way powder spreading scheme, the first powder feeding and spreading device 1 first moves from the right to the left to return to the initial position, and then moves from the left to the right to spread the 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 1 can complete the powder spreading in the process of moving from the right to the left, but should continue to move from the left to the right, so as to avoid interference with the subsequent second powder feeding and spreading device 2 when it moves. 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.

[0086] 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.

[0087] ⑧ Repeat the above steps ③-⑦ until all layers of the workpiece to be manufactured are scanned and melted.

[0088] Embodiment five:

[0089] The additive manufacturing method with a dual powder feeding device provided in this embodiment can further optimize the division of sub-working areas based on the above division, and the boundaries of adjacent sub-working areas change layer by layer according to the manufacturing process requirements. Figure 6 As shown, in the current layer, there is a workpiece section 9 to be scanned and melted adjacent to the A1 area and the A2 area. Figure 2 If the straight line segment boundary shown is used to divide the A1 area and the A2 area, the workpiece section 9 will be divided into two halves, one half in the A1 area and the other half in the A2 area; when the step of layer-by-layer powder spreading and scanning melting of the fourth embodiment is used, the scanning melting of the A1 area and the A2 area is performed separately, resulting in the scanning melting of the workpiece section 9 being divided into two sections, which may cause problems with printing quality and workpiece dimensional accuracy. Therefore, when the current layer is scanned and melted, the boundary of the A2 area can be appropriately expanded, such as Figure 6As shown, the A2 area is allowed to completely contain the workpiece section 9, so that the scanning vector in the slice file of the workpiece section 9 will not be divided into two halves, and there will be no interruption in its scanning and melting. Similarly, for the boundary between the B2 area and the A2 area, and the boundary 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 9 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.

[0090] The technical features of the above embodiments may be arbitrarily combined. 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.

[0091] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. An additive manufacturing device with a multi-feeding 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 to a corresponding powder spreading range in the working area according to a specified layer thickness, and there are overlapping areas in 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 scanning, melting and powder spreading of the sub-working areas according to a predetermined logic.

2. The additive manufacturing equipment with a multi-feeding powder spreading device according to claim 1, characterized in that: The control device controls the scanning device to scan and melt a 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.

3. The additive manufacturing equipment with a multi-feeding powder spreading device according to claim 1, characterized in that: The sub-working areas are arranged perpendicular to the powder spreading direction.

4. The additive manufacturing equipment with a multi-powder feeding and spreading device according to any one of claims 1 to 3, 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 not interfered 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 by the second powder feeding and spreading device, and 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 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 by the first powder feeding and spreading device, and 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.

5. The additive manufacturing equipment with a multi-powder feeding and spreading device according to claim 4, 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 between the A2 area and the B2 area.

6. The additive manufacturing equipment with a multi-feeding powder spreading device according to claim 4, 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 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.

7. An additive manufacturing method using the additive manufacturing equipment with a multi-powder feeding and spreading device according to any one of claims 4 to 6, characterized in that: The geometric model of the workpiece to be manufactured is sliced ​​in layers 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; the layer-by-layer powder spreading and scanning and 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 on 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, repeating steps S1-S5 until all layers of the workpiece to be manufactured are scanned and melted.

8. The additive manufacturing method according to claim 7, characterized in that: The scanning melting action in step S3 is performed after the substrate is lowered, during the lowering of the substrate, or before the substrate is lowered.

9. The additive manufacturing method according to claim 7, characterized in that: If the scanning melting in step S3 is 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.

10. The additive manufacturing method according to claim 7, characterized in that: 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.

11. The additive manufacturing method according to claim 7, characterized in that: The powder spreading is executed and completed by the powder spreading device in the reciprocating motion relative to the working area, wherein one direction of motion in the reciprocating motion is defined as the positive direction, and the other direction of motion is defined as the reverse direction; the powder spreading device executes and completes one layer of powder spreading only during the forward motion, or executes and completes one layer of powder spreading only during the reverse motion, or executes and completes one layer of powder spreading respectively during the forward and reverse motions.

12. The additive manufacturing method according to claim 7, characterized in that: 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.

13. The additive manufacturing method according to claim 7, characterized in that: The boundaries of adjacent sub-working areas change layer by layer as the manufacturing process requires.

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