A special additive manufacturing equipment for forming a complex internal flow channel and a method for preparing a complex internal flow channel

Abstract

The application provides a kind of special additive manufacturing equipment for complex internal runner forming and a method for preparing complex internal runner, the equipment includes powder laying system, laser system, forming bin system and computer control system;The powder laying system includes binder injection bin, fine powder laying bin, fine powder laying head and ultrafine powder laying head;Ultrafine powder laying head lays 5~10 μm powder;The forming bin system includes substrate;The powder laying system is fixed above the forming bin system by slide rail, and under the control of the computer control system, it reciprocates to deliver powder to the surface of the substrate of the forming bin system;The laser system is above the forming bin system, and the laser beam emitted by the laser system scans and heats the powder under the control of the computer control system;After completing the manufacture of each layer of entity, the computer system controls the substrate to descend by a layer of thickness, and then the next layer of entity is manufactured.The complex internal runner surface manufactured by the equipment has smaller surface roughness.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing technology, and in particular relates to a special additive manufacturing equipment for forming complex internal flow channels and a method for preparing complex internal flow channels. Background Technology

[0002] Additive manufacturing is a near-net-shape forming process suitable for manufacturing complex structural parts. Parts with complex internal flow channels are the primary targets for additive manufacturing. However, due to the "layer-by-layer manufacturing" nature of additive manufacturing, the surfaces of additively manufactured parts have obvious texture features and relatively high surface roughness. For parts with complex internal flow channels, excessive surface roughness can affect flow resistance, preventing the part from fully realizing its design performance and failing to meet usage requirements.

[0003] Currently, internal surface treatment processes such as abrasive flow, electrochemical polishing, and water jetting are mainly used to treat complex internal flow channels in additive manufacturing. However, due to the limited internal space and varied geometric dimensions of complex internal flow channels, no single internal surface treatment process can meet the surface treatment requirements of all complex internal flow channels, severely limiting the application of additive manufacturing technology. Currently, the particle size range of raw material powders commonly used in laser additive manufacturing is between 15μm and 53μm. Using smaller particle size powders as raw materials can achieve a smaller powder layer thickness, resulting in lower surface roughness and smoother contours. However, a smaller powder layer thickness leads to longer processing cycles and reduced forming efficiency. Therefore, it is essential to develop a dedicated additive manufacturing equipment and method for forming complex internal flow channels. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a special additive manufacturing equipment for forming complex internal flow channels and a method for preparing complex internal flow channels, wherein the surface of the complex internal flow channels of the additive manufacturing equipment has a small surface roughness.

[0005] This invention provides a special additive manufacturing equipment for forming complex internal flow channels, including a powder delivery system, a laser system, a forming chamber system, and a computer control system;

[0006] The powder spreading system includes a binder spraying chamber, a fine powder spreading chamber, a fine powder spreading head, and an ultrafine powder spreading head; the ultrafine powder spreading head spreads powder of 5~10μm.

[0007] The forming chamber system includes a base plate;

[0008] The powder delivery system is fixed above the forming chamber system by a slide rail and reciprocates under the control of the computer control system to deliver powder to the substrate surface of the forming chamber system.

[0009] The laser system is above the forming bin system, and the laser beam emitted by the laser system is used for scanning and heating the powder under the control of the computer control system; after the manufacturing of each layer of entity is completed, the computer system controls the substrate to descend by a layer of thickness, and the next layer of entity is manufactured.

[0010] Preferably, the binder spraying bin is at the front end in the movement direction; the fine powder conveying bin is behind the binder spraying bin; the fine powder conveying head and the superfine powder conveying head are at the last end in the movement direction and are fixed side by side on the side wall slide rail of the fine powder conveying bin and move along the direction perpendicular to the movement direction of the fine powder conveying bin.

[0011] Preferably, the fine powder conveying head conveys the powder with a particle size of 15-53 microns.

[0012] Preferably, the binder spraying bin is a rectangular parallelepiped.

[0013] The large surface of the side wall of the binder spraying bin is perpendicular to the substrate.

[0014] The top surface of the binder spraying bin is provided with a binder pouring inlet, and the bottom surface is provided with a plurality of binder spraying holes with a diameter of 0.5-1 mm.

[0015] The length of the bottom surface of the binder spraying bin is the same as the length of the substrate.

[0016] Preferably, the fine powder conveying bin is a right-angled trapezoidal body.

[0017] Preferably, the top surface of the fine powder conveying bin is provided with a powder pouring inlet.

[0018] The bottom surface of the fine powder conveying bin is provided with a powder outlet.

[0019] The length of the bottom surface of the fine powder conveying bin is the same as the length of the substrate.

[0020] Preferably, the fine powder conveying head is funnel-shaped.

[0021] The top surface of the fine powder conveying head is provided with a powder pouring inlet.

[0022] The bottom of the fine powder conveying head is provided with a powder conveying pipe with a diameter of 1-2 mm.

[0023] Preferably, the superfine powder conveying head is funnel-shaped.

[0024] The top surface of the superfine powder conveying head is provided with a powder pouring inlet.

[0025] The bottom of the superfine powder conveying head is provided with a powder conveying pipe with a diameter of 1-2 mm.

[0026] The application provides a method for preparing a complex internal runner by using the additive manufacturing equipment.

[0027] (1) the powder conveying system moves from one side of the forming bin to the other side, and sprays a layer of organic binder on the substrate during the movement, and lays a layer of 5-10 mu m ultra-fine powder on the surface forming area of the complex internal runner, and lays a layer of 15-53 mu m fine powder on other areas;

[0028] (2) using a scraper to move from one side of the forming bin to the other side;

[0029] (3) according to the set laser scanning path and process parameters, using the laser system to heat the powder to be processed into a part for the first time;

[0030] (4) according to the set laser scanning path and process parameters, using the laser system to heat the powder to be processed into a part for the second time, to complete the processing of the first layer;

[0031] (5) after the first layer is completed, the substrate of the forming bin is lowered by one layer thickness, and the powder laying system is returned to the position before the processing starts at the same time;

[0032] (6) repeat steps (1)-(5) until the entire part manufacturing is completed.

[0033] Preferably, the laser energy density used in the first heating in step (3) is 0.1 J / mm-0.2 J / mm;

[0034] The laser energy density used in the second heating in step (4) is 0.3 J / mm-0.5 J / mm.

[0035] The application provides a special additive manufacturing equipment for complex internal runner forming, which comprises a powder laying system, a laser system, a forming bin system and a computer control system; the powder laying system comprises a binder spraying bin, a fine powder laying bin, a fine powder laying head and an ultra-fine powder laying head; the ultra-fine powder laying head lays 5-10 mu m powder; the forming bin system comprises a substrate; the powder laying system is fixed above the forming bin system through a slide rail and reciprocates under the control of the computer control system to convey the powder to the surface of the substrate of the forming bin system; the laser system is above the forming bin system, and the laser beam emitted by the laser system is scanned and heated under the control of the computer control system, and after the manufacturing of each layer of entity is completed, the computer system controls the substrate to be lowered by one layer thickness, and the next layer of entity manufacturing is carried out. The special additive manufacturing equipment makes the region on the surface of the complex internal runner accurately lay 5-10 mu m ultra-fine powder, and other regions lay fine powder, so that the additive manufacturing of the complex internal runner surface has smaller surface roughness, and solves the problem that the surface roughness of the existing additive manufacturing of the complex internal runner surface is large and difficult to fully meet the use requirements. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 Structure diagram of the special additive manufacturing equipment for the complex internal flow channel forming of the application;

[0037] Figure 2 Structure diagram of the powder conveying system of the application;

[0038] Figure 3 Front view of the binder injection bin of the application;

[0039] Figure 4 Side view of the binder injection bin of the application;

[0040] Figure 5 Top view of the binder injection bin of the application;

[0041] Figure 6 Front view of the fine powder conveying bin of the application; Figure 3 Sectional view of the A-A plane of the fine powder conveying bin of the application;

[0042] Figure 7 Front view of the fine powder conveying bin of the application;

[0043] Figure 8 Side view of the fine powder conveying bin of the application;

[0044] Figure 9 Top view of the fine powder conveying bin of the application;

[0045] Figure 10 Front view of the fine powder conveying head of the application; Figure 7 Sectional view of the B-B plane of the fine powder conveying head of the application;

[0046] Figure 11 Front view of the fine powder conveying head of the application;

[0047] Figure 12 Side view of the fine powder conveying head of the application;

[0048] Figure 13 Top view of the fine powder conveying head of the application;

[0049] Figure 14 Front view of the superfine powder conveying head of the application; Figure 11 Sectional view of the C-C plane of the superfine powder conveying head of the application;

[0050] Figure 15 Front view of the superfine powder conveying head of the application;

[0051] Figure 16 Side view of the superfine powder conveying head of the application;

[0052] Figure 17 Top view of the superfine powder conveying head of the application;

[0053] Figure 18 Front view of the superfine powder conveying head of the application; Figure 16 Sectional view of the D-D plane of the superfine powder conveying head of the application;

[0054] Wherein, 1 is a powder conveying system, 2 is a laser system, 3 is a forming bin system, 4 is a computer control system, 5 is a sliding rail, 6 is a base plate, 7 is a scraper, 8 is a binder injection bin, 9 is a fine powder conveying bin, 10 is a fine powder conveying head, 11 is a superfine powder conveying head, 12 is a fine powder conveying bin side wall sliding rail, 13 is a binder injection hole, 14 is a powder outlet, 15 is a powder conveying pipe, and 16 is a vibrating device. DETAILED DESCRIPTION

[0055] The application provides a special additive manufacturing equipment for complex internal runner forming, which comprises a powder conveying system, a laser system, a forming bin system and a computer control system.

[0056] The powder conveying system comprises a binder injection bin, a fine powder conveying bin, a fine powder conveying head and a superfine powder conveying head.

[0057] The forming bin system comprises a base plate.

[0058] The powder conveying system is fixed above the forming bin system through a sliding rail and reciprocally moves under the control of the computer control system to convey the powder to the surface of the base plate of the forming bin system.

[0059] The laser system is above the forming bin system, and a laser beam emitted by the laser system is controlled by the computer control system to scan and heat the powder.

[0060] Referring to Figure 1 , Figure 1 It is a structural schematic view of the special additive manufacturing equipment for complex internal runner forming, wherein 1 is a powder conveying system, 2 is a laser system, 3 is a forming bin system, 4 is a computer control system, 5 is a sliding rail, 6 is a base plate, and 7 is a scraper.

[0061] The special additive manufacturing equipment for complex internal runner forming comprises a powder conveying system, and the powder conveying system comprises a binder injection bin, a fine powder conveying bin, a fine powder conveying head and a superfine powder conveying head. Figure 2 It is a structural schematic view of the powder conveying system, wherein 8 is a binder injection bin, 9 is a fine powder conveying bin, 10 is a fine powder conveying head, 11 is a superfine powder conveying head, and 12 is a fine powder conveying bin side wall sliding rail.

[0062] Figures 3-5 It is a front view, a side view and a top view of the binder injection bin, respectively. Figure 6 It is Figure 3 A sectional view of A-A plane.

[0063] Figures 7-9 It is the front view, side view and top view of the fine powder paving head of the present application. Figure 10 It is the front view, side view and top view of the fine powder paving head of the present application. Figure 7 It is the sectional view of B-B plane.

[0064] Figures 11-13 It is the front view, side view and top view of the fine powder paving head of the present application. Figure 14 It is the front view, side view and top view of the fine powder paving head of the present application. Figure 11 It is the sectional view of C-C plane.

[0065] Figures 15-17 It is the front view, side view and top view of the fine powder paving head of the present application. Figure 18 It is the front view, side view and top view of the fine powder paving head of the present application. Figure 16 It is the sectional view of D-D plane.

[0066] In the present application, the adhesive spraying bin is at the front end in the moving direction; the fine powder paving bin is behind the adhesive spraying bin; the fine powder paving head and the superfine powder paving head are at the last end in the moving direction and are fixed side by side on the side wall slide rail of the fine powder paving bin and move in the direction perpendicular to the moving direction of the fine powder paving bin. The adhesive spraying bin is at the front end in the moving direction to spray the adhesive to the substrate first so that the subsequent powder can be fixed better. The fine powder paving bin is behind the adhesive spraying bin because the fine powder paving bin is adjacent to the large face of the adhesive spraying bin and has the same size, so the arrangement is easy to assemble when the equipment is manufactured, and the difficulty of equipment manufacturing is reduced.

[0067] In the present application, the adhesive spraying bin is a cuboid, and the large face of the side wall is perpendicular to the moving direction and the substrate. The top face of the adhesive spraying bin is provided with an adhesive pouring inlet, and the bottom face is provided with a plurality of adhesive spraying holes with a diameter of 0.5-1 mm (see Figure 5 and Figure 6 13); the length of the bottom face of the adhesive spraying bin is the same as the length of the substrate. The adhesive enters the adhesive spraying bin through the pouring inlet and is sprayed to the surface of the substrate through the spraying holes under the action of air pressure. The adhesive spraying bin is designed as a cuboid, which can be as simple as possible in structure under the premise of realizing the function, is convenient for the manufacturing and maintenance of the equipment, and improves the economic benefit of the present application. The length of the bottom face is the same as the substrate, which ensures that the adhesive can cover all areas of the substrate. The diameter of the adhesive spraying holes provided on the bottom face is between 0.5 mm and 1 mm. If the diameter is too small, the processing difficulty of the holes is too great; if the diameter is too large, the adhesive spraying effect is not good.

[0068] In the present application, the fine powder paving bin is a right-angled trapezoidal body, and the fine powder paving bin is adjacent to the large face of the adhesive spraying bin and has the same size. The top face of the fine powder paving bin is provided with a powder pouring inlet, and the bottom face is provided with a powder outlet with a width of 106-110 μm (see Figure 9 and Figure 10The powder is poured into the fine powder laying warehouse through the powder pouring inlet, and is laid on the surface of the substrate sprayed with the binder through the powder outlet. The fine powder laying head is designed as a right trapezoidal body, which can lay the powder on the surface of the substrate under the action of gravity, and has a simple structure under the premise of ensuring the function, facilitates the manufacture and maintenance of the equipment, and improves the economic benefit of the application. The length of the bottom surface is the same as that of the substrate, so as to ensure that the powder can cover all areas of the substrate. The width of the powder outlet of the bottom surface is between 106 μm and 110 μm. If the width is too small, the flowability of the powder in the falling process is poor, the powder is not uniformly laid, and a pore defect is formed in the part, so that the quality is unqualified. If the width is too large, too much powder falls, which causes waste of raw materials.

[0069] The fine powder laying head is funnel-shaped. The top surface of the fine powder laying head is provided with a powder pouring inlet; the bottom of the fine powder laying head is provided with a powder feeding pipe with a diameter of 1-2 mm (see Figure 11 In the application, the fine powder laying head lays 15-53 μm powder; the fine powder is a commonly used additive manufacturing powder on the market which is well known to those skilled in the art.

[0070] The ultra-fine powder laying head is funnel-shaped, which can lay the powder on the surface of the substrate under the action of gravity, and has a simple structure under the premise of ensuring the function, facilitates the manufacture and maintenance of the equipment, and improves the economic benefit of the application. The top surface of the ultra-fine powder laying head is provided with a powder pouring inlet; the bottom of the ultra-fine powder laying head is provided with a powder feeding pipe with a diameter of 1-2 mm. If the diameter is too small, the powder is easy to block the powder feeding pipe, the powder is not uniformly laid, and a pore defect is formed in the part, so that the quality is unqualified. If the diameter is too large, too much powder falls, which causes waste of raw materials. The ultra-fine powder laying head is provided with a vibrating device, which vibrates during powder feeding. This is because the ultra-fine powder has poor flowability due to small particle size. Therefore, the vibrating device is used to assist the ultra-fine powder laying, so as to ensure the uniformity of the powder laying, and the finally formed part has good quality. The ultra-fine powder laying head lays 5-10 μm powder. The powder with a particle size less than 5 μm has poor flowability and is easy to agglomerate and block the powder outlet. The powder with a particle size greater than 10 μm has a large surface roughness after laser heating and melting, and the effect of improving the surface roughness is not obvious.

[0071] The additive manufacturing equipment for forming complex internal flow channels comprises a laser system; the laser system is above the forming warehouse system. The laser system emits a laser beam; the laser beam scans and heats the powder on the surface of the substrate to be machined into a part under the control of a computer control system.

[0072] The additive manufacturing equipment for forming complex internal flow channels comprises a forming warehouse system;

[0073] The special additive manufacturing equipment for complex internal flow channel forming provided by the application comprises a computer control system.

[0074] The application provides a method for preparing a complex internal flow channel by using the additive manufacturing equipment.

[0075] (1) the powder conveying system moves from one side of the forming bin to the other side, and sprays a layer of organic binder on the substrate during the movement, and lays a layer of 5-10 mu m ultra-fine powder on the complex internal flow channel surface forming area, and lays a layer of 15-53 mu m fine powder on other areas;

[0076] (2) the scraper is used to move from one side of the forming bin to the other side;

[0077] (3) according to the set laser scanning path and process parameters, the laser system is used to heat the powder to be processed into a part for the first time;

[0078] (4) according to the set laser scanning path and process parameters, the laser system is used to heat the powder to be processed into a part for the second time, and the first layer is completed;

[0079] (5) after the first layer is completed, the substrate of the forming bin is lowered by one layer thickness, and the powder laying system is returned to the position before the start of processing at the same time;

[0080] (6) repeat steps (1)-(5) until the entire part manufacturing is completed.

[0081] In the application, the binder spraying bin sprays the binder downward during the movement. The fine powder laying bin has a large powder outlet size and a large amount of powder laying, and using the fine powder laying bin to lay powder in the area which is not processed into a part can improve the processing efficiency. In the application, the fine powder laying head is used to lay powder in the area which is processed into a part, and the ultra-fine powder laying head is used to lay powder in the area which is processed into a complex internal flow channel surface, so that the advantages of a small diameter of the powder conveying pipe can be utilized, different particle sizes of powder can be accurately laid in different areas, and the forming quality of the final part is ensured.

[0082] In the application, a lower laser energy density is used when the powder is heated for the first time, so that the binder can be fully volatilized, and the laser energy density is preferably 0.1 J / mm-0.2 J / mm; in this way, the powder can be directly heated, the binder cannot be volatilized in time, a large number of pores are formed in the finally manufactured part, and the quality of the part is unqualified.

[0083] The second heating of the powder to be processed into a part uses a higher laser energy density to make the powder fuse into a solid; the laser energy density used in the second heating is 0.3 J / mm to 0.5 J / mm.

[0084] The method provided by the application can make the region processed into a complex inner runner surface accurately spread the superfine powder with a particle size of 5-10 microns, and the other regions spread the fine powder with a particle size of 15-53 microns, so that the additive manufacturing complex inner runner surface has smaller surface roughness, and solves the problem that the surface roughness of the existing additive manufacturing complex inner runner surface is large and it is difficult to fully meet the use requirements.

[0085] The application can not only achieve the best spreading effect, but also minimize the processing difficulty and the use of materials, so that the cost and difficulty of the device and method of the application are relatively low.

[0086] In order to further illustrate the application, the special additive manufacturing device for complex inner runner forming and the method for preparing a complex inner runner provided by the application are described in detail below in combination with embodiments, but they should not be understood as limiting the protection scope of the application.

[0087] Example 1

[0088] The embodiment provides a special additive manufacturing device for complex inner runner forming, which comprises four systems: a powder spreading system, a laser system, a forming bin system and a computer control system.

[0089] The powder spreading system is fixed above the forming bin system through a sliding rail and reciprocates under the control of the computer control system to spread the powder from the top to the surface of the substrate (the substrate has a size of 250mm*250mm); the laser system is above the forming bin system, and a laser beam scans and heats the powder to be processed into a part on the surface of the substrate under the control of the computer control system; after completing the manufacturing of one layer of solid, the computer system controls the substrate to descend to a position of one layer thickness, and then the manufacturing of the next layer of solid is performed.

[0090] The powder spreading system comprises four parts: a binder spraying bin, a fine powder spreading bin, a fine powder spreading head and a superfine powder spreading head.

[0091] The binder spraying bin is at the front end of the movement direction, the fine powder spreading bin is behind the binder spraying bin, the fine powder spreading head and the superfine powder spreading head are at the last end of the movement direction and are fixed side by side on the sliding rail of the side wall of the fine powder spreading bin and move along the direction perpendicular to the movement direction of the fine powder spreading bin.

[0092] The adhesive injection bin is a cuboid, the large face of the side wall is perpendicular to the moving direction and the substrate. The top face is provided with an adhesive pouring inlet, and the bottom face is provided with a plurality of adhesive injection holes with a diameter of 0.5 mm. The length of the bottom face is 250 mm, so that the adhesive can cover all areas of the substrate. The adhesive enters the adhesive injection bin through the pouring inlet and is sprayed to the surface of the substrate through the injection holes under the action of air pressure.

[0093] The fine powder conveying bin is a right-angled trapezoidal body. The fine powder conveying bin is adjacent to the large face of the adhesive injection bin and has the same size. The top face of the fine powder conveying bin is provided with a powder pouring inlet, and the bottom face is provided with a powder outlet with a width of 110 μm. The length of the bottom face is 250 mm, so that the powder can cover all areas of the substrate. The powder enters the fine powder conveying bin through the pouring inlet and is conveyed to the surface of the substrate on which the adhesive has been sprayed through the powder outlet.

[0094] The fine powder conveying head is funnel-shaped and has a powder pouring inlet on the top face. The bottom of the fine powder conveying head is provided with a powder conveying pipe with a diameter of 1 mm.

[0095] The superfine powder conveying head is funnel-shaped and has a powder pouring inlet on the top face. The bottom of the superfine powder conveying head is provided with a powder conveying pipe with a diameter of 1 mm. The superfine powder conveying head is provided with a vibrating device, which vibrates during powder conveying.

[0096] The embodiment also provides a special additive manufacturing method for forming a complex internal flow channel of a GH3625 alloy fuel injection rod based on the above-mentioned device, and the steps are as follows:

[0097] 1) The powder conveying system moves from one side of the forming bin to the other side, sprays a layer of organic adhesive on the substrate during the movement, and conveys a layer of GH3625 alloy powder with a particle size of 5 μm to 10 μm on the surface forming area of the complex internal flow channel, and conveys a layer of GH3625 alloy powder with a particle size of 15 μm to 53 μm on other areas;

[0098] 2) The scraper is used to move from one side of the forming bin to the other side;

[0099] 3) The laser system is used to heat the GH3625 alloy powder to be machined into a part for the first time according to the set laser scanning path and process parameters (laser energy density is 0.12 J / mm);

[0100] 4) The laser system is used to heat the GH3625 alloy powder to be machined into a part for the second time according to the set laser scanning path and process parameters (laser energy density is 0.3 J / mm), and the first layer is completed;

[0101] 5) After the first layer is completed, the substrate of the forming bin is lowered by one layer thickness, and the powder conveying system returns to the position before the start of the machining at the same time.

[0102] 6) Repeat steps 1)~5) until all parts are manufactured. The inner surface roughness is measured by a roughness meter, and the average surface roughness Ra is 3.2 μm.

[0103] Example 2

[0104] This embodiment provides a special additive manufacturing equipment for complex internal flow channel forming, which includes four systems: a powder spreading system, a laser system, a forming bin system, and a computer control system.

[0105] The powder spreading system is fixed above the forming bin system by a slide rail and reciprocates under the control of the computer control system to spread powder from above to the surface of the substrate (substrate size 650 mm x 650 mm); the laser system is above the forming bin system, and the laser beam scans and heats the powder to be processed into a part on the surface of the substrate under the control of the computer control system; after completing the manufacturing of each layer of the entity, the computer system controls the substrate to descend to a position of one layer thickness, and then the next layer of entity manufacturing is performed.

[0106] The powder spreading system includes four parts: a binder spraying bin, a fine powder spreading bin, a fine powder spreading head, and a superfine powder spreading head.

[0107] The binder spraying bin is at the front end of the motion direction, the fine powder spreading bin is behind the binder spraying bin, the fine powder spreading head and the superfine powder spreading head are at the last end of the motion direction and are fixed side by side on the slide rail of the side wall of the fine powder spreading bin and move along a direction perpendicular to the motion direction of the fine powder spreading bin.

[0108] The binder spraying bin is a rectangular parallelepiped, and the large face of the side wall is perpendicular to the motion direction and the substrate. The top face is provided with a binder pouring inlet, and the bottom face is provided with a plurality of binder spraying holes with a diameter of 0.5 mm. The length of the bottom face is 650 mm, which ensures that the binder can cover all areas of the substrate. The binder enters the binder spraying bin through the pouring inlet and is sprayed to the surface of the substrate through the spraying holes under the action of air pressure.

[0109] The fine powder spreading bin is a right trapezoidal body. The fine powder spreading bin is adjacent to the large face of the binder spraying bin and has the same size. The top face of the fine powder spreading bin is provided with a powder pouring inlet, and the bottom face is provided with a powder outlet with a width of 165 μm. The length of the bottom face is 650 mm, which ensures that the powder can cover all areas of the substrate. The powder enters the fine powder spreading bin through the pouring inlet and is spread to the surface of the substrate on which the binder has been sprayed through the powder outlet.

[0110] The fine powder spreading head is funnel-shaped and has a powder pouring inlet on the top face. The bottom of the fine powder spreading head is provided with a powder feeding pipe with a diameter of 2 mm.

[0111] The superfine powder laying head is funnel-shaped, and the top surface has a powder inlet. The bottom of the superfine powder laying head is provided with a powder feeding pipe with a diameter of 2 mm. The superfine powder laying head is provided with a vibration device, and the vibration device is used for vibrating and feeding powder during powder feeding.

[0112] The embodiment also provides an additive manufacturing method for forming a complex inner flow channel of an AlSi10Mg alloy fuel pump housing based on the above device, and the steps are as follows:

[0113] 1) The powder laying system moves from one side of the forming bin to the other side, sprays a layer of organic binder on the substrate during the movement, and lays a layer of AlSi10Mg alloy powder with a particle size of 5 μm to 10 μm on the surface forming area of the complex inner flow channel, and lays a layer of AlSi10Mg alloy powder with a particle size of 15 μm to 53 μm on other areas;

[0114] 2) The scraper is used to move from one side of the forming bin to the other side;

[0115] 3) The laser system is used to heat the AlSi10Mg alloy powder to be machined into a part according to the set laser scanning path and process parameters (laser energy density is 0.2 J / mm) for the first time;

[0116] 4) The laser system is used to heat the AlSi10Mg alloy powder to be machined into a part according to the set laser scanning path and process parameters (laser energy density is 0.4 J / mm) for the second time, and the first layer is completed;

[0117] 5) After the first layer is completed, the substrate of the forming bin is lowered by one layer thickness, and the powder laying system is returned to the position before the start of the machining at the same time;

[0118] 6) Steps 1) to 5) are repeated until the whole part manufacturing is completed. The inner surface roughness is measured by using a roughness measuring instrument, and the average surface roughness Ra is 4.6 μm.

[0119] From the above embodiment, the application provides a special additive manufacturing equipment for complex inner flow channel forming, which comprises a powder paving system, a laser system, a forming bin system and a computer control system; the powder paving system comprises a binder spraying bin, a fine powder paving bin, a fine powder paving head and a superfine powder paving head; the superfine powder paving head paves 5-10 mu m powder; the forming bin system comprises a base plate; the powder paving system is fixed above the forming bin system through a slide rail and reciprocates under the control of the computer control system to deliver powder to the surface of the base plate of the forming bin system; the laser system is above the forming bin system, and the laser beam emitted by the laser system heats the powder under the control of the computer control system; after the manufacturing of each layer of entity is completed, the computer system controls the base plate to descend by a layer of thickness, and the manufacturing of the next layer of entity is performed. The special additive manufacturing equipment paves superfine powder with a particle size of 5-10 mu m to the region on the surface of which the complex inner flow channel is processed, and paves fine powder to other regions, so that the additive manufacturing of the complex inner flow channel surface has smaller surface roughness, and the problem that the surface roughness of the existing additive manufacturing complex inner flow channel is large and it is difficult to fully meet the use requirements is solved. Experimental results show that the surface roughness of the complex inner flow channel is 3-5 mu m.

[0120] The above only describes the preferred embodiments of the application, and it should be noted that those skilled in the art can make several improvements and refinements without departing from the principles of the application, and these improvements and refinements should also be considered as the protection scope of the application.

Claims

1. A special additive manufacturing equipment for complex internal runner forming, comprising a powder spreading system, a laser system, a forming bin system and a computer control system. The powder spreading system comprises a binder spraying bin, a fine powder spreading bin, a fine powder spreading head and a superfine powder spreading head; the superfine powder spreading head spreads 5-10 μm powder; The forming bin system comprises a base plate; The powder spreading system is fixed above the forming bin system through a slide rail, and moves back and forth under the control of the computer control system to deliver powder to the surface of the base plate of the forming bin system; The laser system is above the forming bin system, and the laser beam emitted by the laser system heats the powder under the control of the computer control system; after the manufacturing of each layer of entity is completed, the computer system controls the base plate to drop by a layer of thickness, and then the manufacturing of the next layer of entity is performed; the adhesive injection chamber is located at the frontmost position in the movement direction; The fine powder spreading bin is behind the binder spraying bin; the fine powder spreading head and the superfine powder spreading head are fixed side by side at the last end of the moving direction on the side wall slide rail of the fine powder spreading bin, and move along a direction perpendicular to the moving direction of the fine powder spreading bin; The fine powder spreading head spreads 15-53 μm powder; The binder spraying bin is a rectangular parallelepiped; the large surface of the side wall of the binder spraying bin is perpendicular to the base plate; the top surface of the binder spraying bin is provided with a binder pouring inlet, and the bottom surface is provided with a plurality of binder spraying holes with a diameter of 0.5-1 mm; the length of the bottom surface of the binder spraying bin is the same as the length of the base plate; The fine powder spreading head is funnel-shaped; the top surface of the fine powder spreading head is provided with a powder pouring inlet; the bottom of the fine powder spreading head is provided with a powder feeding pipe with a diameter of 1-2 mm; The top surface of the fine powder spreading bin is provided with a powder pouring inlet; the bottom surface of the fine powder spreading bin is provided with a powder outlet; the length of the bottom surface of the fine powder spreading bin is the same as the length of the base plate; The superfine powder spreading head is funnel-shaped; the top surface of the superfine powder spreading head is provided with a powder pouring inlet; the bottom of the superfine powder spreading head is provided with a powder feeding pipe with a diameter of 1-2 mm; The powder delivery system moves from one side of the forming bin to the other side, sprays a layer of organic binder on the base plate during the movement, spreads a layer of 5 μm-10 μm superfine powder on the complex internal runner surface forming area, and spreads a layer of 15 μm-53 μm fine powder on other areas, and performs first heating and second heating; the laser energy density used in the first heating is 0.1 J / mm-0.2 J / mm; the laser energy density used in the second heating is 0.3 J / mm-0.5 J / mm.

2. The complex internal flow channel forming application-specific additive manufacturing apparatus of claim 1, wherein, The fine powder spreading bin is a right trapezoidal body.

3. A method for preparing a complex internal runner by using the additive manufacturing equipment according to any one of claims 1-2, comprising the following steps: (1) The powder delivery system moves from one side of the forming bin to the other side, sprays a layer of organic binder on the base plate during the movement, spreads a layer of 5 μm-10 μm superfine powder on the complex internal runner surface forming area, and spreads a layer of 15 μm-53 μm fine powder on other areas; (2) A scraper is used to move from one side of the forming bin to the other side; (3) According to the set laser scanning path and process parameters, the laser system is used to heat the powder to be processed into a part for the first time; (4) According to the set laser scanning path and process parameters, the laser system is used to heat the powder to be processed into a part for the second time, and the first layer is completed; (5) After the first layer is completed, the base plate of the forming bin is lowered by one layer thickness, and the powder laying system returns to the position before the start of processing at the same time; (6) Repeat steps (1) ~ (5) until the entire part manufacturing is completed.

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