An additive hybrid manufacturing chamber apparatus and method for shaping long tubular parts

Abstract

A kind of long tube class part additive composite manufacturing forming chamber device and forming method, including box, top in box is equipped with base plate, base plate and fixture guide rail body top are connected, fixture guide rail body and air bag clamp are connected, air bag clamp left and right sides are connected by first, second connecting rod and first, second screw stepper motor, first, second screw stepper motor is connected in the middle part of box by annular supporting plate;Air bag clamp front and rear sides are connected by first, second air pipe connecting body and first, second air pump, first, second air pump is connected in the front and rear of box by annular supporting plate;Fixture guide rail body lower part and push rod are connected, push rod left and right sides are connected by third, fourth connecting rod and third, fourth screw stepper motor, third, fourth screw stepper motor is fixed to the left and right of box;First, second, third and fourth screw stepper motor is coordinated to control the up and down movement of base plate;The present application improves material utilization, reduces manufacturing cost and reduces manufacturing time.

Description

Technical Field

[0001] The present invention belongs to the technical field of additive composite manufacturing, and in particular relates to an additive composite manufacturing forming chamber device and a forming method for long tubular parts. Background Art

[0002] Additive manufacturing is an emerging technology that transforms three-dimensional models into two-dimensional slices and forms them layer by layer, enabling the integrated manufacture of complex-shaped components. It boasts advantages such as short production cycles, high material utilization, digitization, automation, and personalization, and is considered a transformative technology for integrated design and manufacturing. Laser powder bed fusion (L-PBF), with its high precision, high quality, and high density, is one of the most representative and widely used technologies in metal additive manufacturing, capable of meeting the complex shapes and high-precision requirements of core components in the hot end of aircraft engines and gas turbines.

[0003] Materials with titanium as the matrix and other elements added to them are called titanium alloys. As a new structural material, titanium alloys are endowed with excellent comprehensive properties, such as good crack growth resistance and fatigue strength, high specific strength and good fracture toughness, low-temperature toughness, and excellent corrosion resistance. With a maximum operating temperature of 550°C, titanium alloys are widely used in aviation, aerospace, chemical engineering, shipbuilding, and other industrial sectors. For example, TA18 high-strength titanium tubes are used in hydraulic piping systems, meeting not only the high strength requirements but also the demand for lightweight components in aerospace and other fields.

[0004] For Figure 1 The titanium alloy long tube parts shown in the figure have a straight tube length of more than 40cm and a complex structure of the curved tube part. The traditional manufacturing method uses a complex manufacturing process of forging blanks + CNC machining, such as the document "A method for preparing low-cost titanium alloy thin-walled tubes". This process has a large amount of CNC machining and a very low material utilization rate. The significant feature of laser powder bed melting technology is that it can perform high-precision manufacturing of complex-shaped parts with high material utilization rate. However, it is limited by the height limit of the formed parts by traditional additive equipment, resulting in the inability of laser powder bed melting technology to form parts in one piece. Figure 1 The titanium alloy long tube parts shown in the figure are priced at RMB 800-900 / kg. Even if the laser powder bed fusion technology is used to form the titanium alloy long tube parts in one piece, the printing cost is still high. Figure 1 For the titanium alloy long tube parts shown in the figure, exploring an additive composite manufacturing method that combines traditional manufacturing and additive manufacturing is of great significance for improving material utilization, breaking the limitations of traditional additive equipment on the height of formed parts, reducing manufacturing costs and reducing manufacturing time. Summary of the Invention

[0005] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a long tube type part additive composite manufacturing forming chamber device and a forming method, which can be used in additive equipment of laser powder bed fusion technology under the premise of ensuring the forming precision of the part, breaking the height limit of the traditional additive equipment; the forming method improves the material utilization rate, reduces the manufacturing cost and reduces the manufacturing time.

[0006] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0007] An additive composite manufacturing forming chamber device for long tube type parts, comprising a box body 1, a base plate 19 is arranged at the top of the box body 1, the base plate 19 is connected with the top of a clamp guide rail body 20 below, the clamp guide rail body 20 is connected with an air bag clamp 21, the air bag clamp 21 moves up and down along the clamp guide rail body 20; the left and right sides of the air bag clamp 21 are connected through a first connecting rod 2, a second connecting rod 3, a first screw nut 14 of a first screw step motor 4 and a second screw nut 15 of a second screw step motor 5 respectively, the first screw step motor 4 and the second screw step motor 5 are symmetrically connected on a ring-shaped supporting plate 16, and the ring-shaped supporting plate 16 is connected to the outer side of the middle part of the box body 1.

[0008] The left and right sides of the air bag clamp 21 are connected with a first air pipe connecting body 10 and a second air pipe connecting body 11 respectively, the first air pipe connecting body 10 and the second air pipe connecting body 11 are connected with a first air pump 12 and a second air pump 13 respectively, and the first air pump 12 and the second air pump 13 are symmetrically connected to the front and back of the box body 1 through the ring-shaped supporting plate 16.

[0009] The lower part of the clamp guide rail body 20 is connected with a push rod 22 below, the left and right sides of the push rod 22 are connected through a third connecting rod 6, a fourth connecting rod 7, a third screw nut 17 of a third screw step motor 8 and a fourth screw nut 18 of a fourth screw step motor 9 respectively, and the third screw step motor 8 and the fourth screw step motor 9 are fixed to the left and right sides of the box body 1; the first screw step motor 4, the second screw step motor 5, the third screw step motor 8 and the fourth screw step motor 9 coordinately control the up and down movement of the base plate 19.

[0010] The screw of the first screw step motor 4 cooperates with the first screw nut 14, the screw of the second screw step motor 5 cooperates with the second screw nut 15, the screw of the third screw step motor 8 cooperates with the third screw nut 17, and the screw of the fourth screw step motor 9 cooperates with the fourth screw nut 18 to form a roller screw transmission.

[0011] The first air pipe connecting body 10 and the second air pipe connecting body 11 both use rubber air pipes with sufficient length, which cooperate with the up and down movement of the air bag clamp 21.

[0012] The expansion and contraction structure of the airbag clamp 21 is an annular rubber airbag with a thickness of not less than 5 mm. After the annular rubber airbag expands and contracts, the diameter of the outer wall of the pipe clamped by the annular rubber airbag ranges from 10 to 80 mm. The overall airtightness of the airbag clamp 21 is good. After expansion and contraction, it forms a close annular contact with the outer wall of the clamped pipe and provides sufficient clamping force.

[0013] The substrate 19 is a circular substrate with the same diameter as the inner wall of the box 1 and a thickness of not less than 30 mm. A circular opening 1901 is opened in the middle, and the circular opening 1901 is used for spreading powder before printing parts.

[0014] The upper part of the box body 1 has four windows, which facilitate the installation of the first connecting rod 2, the second connecting rod 3, the first tracheal connector 10 and the second tracheal connector 11; the lower part of the box body 1 also has four windows, the front and rear windows facilitate the installation of the third connecting rod 6 and the fourth connecting rod 7, and the left and right windows limit the displacement stroke of the third connecting rod 6 and the fourth connecting rod 7.

[0015] The annular support plate 16 includes an outer flat plate and an inner vertical plate connected thereto; the outer flat plate is provided with threaded holes for fixing the first screw stepper motor 4, the second screw stepper motor 5, the first air pump 12, and the second air pump 13 to the annular support plate 16 by bolts; the inner vertical plate is provided with through holes and is connected to the outer wall of the box body 1 by bolts.

[0016] The thickness of the annular support plate 16 is not less than 20 mm to ensure sufficient rigidity.

[0017] The clamp guide rail body 20 is provided with a guide rail inside, and the airbag clamp 21 moves up and down along the guide rail; windows are opened around the middle of the clamp guide rail body 20 to limit the displacement stroke of the first connecting rod 2, the second connecting rod 3, the first tracheal connector 10 and the second tracheal connector 11.

[0018] The first lead screw stepper motor 4 , the second lead screw stepper motor 5 , the third lead screw stepper motor 8 and the fourth lead screw stepper motor 9 coordinate to control the up and down movement distance of the substrate 19 to be 200 mm.

[0019] The precision of the first lead screw stepper motor 4 , the second lead screw stepper motor 5 , the third lead screw stepper motor 8 and the fourth lead screw stepper motor 9 is P1 level.

[0020] The push rod 22 comprises a straight rod portion and a disc portion connected to the top thereof; the disc portion has a cylindrical hollow portion in the middle for placing the straight tube portion of a long tube component.

[0021] The forming method of the additive composite manufacturing forming chamber device for long tubular parts comprises the following steps:

[0022] S1. Divide titanium alloy long tube parts into straight tube parts and curved tube parts;

[0023] S2. The straight tube is formed by extrusion process;

[0024] S3. The curved tube is formed using laser powder bed fusion technology. The tube opening of the straight tube formed by the extrusion process is sealed with a reducing plug. The tube is then placed in the forming chamber. The first air pump 12 and the second air pump 13 operate to inflate the airbag clamp 21 until the airbag clamp 21 contacts the outer wall of the straight tube and provides sufficient clamping force.

[0025] S4. The first screw stepper motor 4 and the second screw stepper motor 5 coordinate and control the movement of the airbag clamp 21 to fine-tune the nozzle so that the upper surface of the substrate 19 is flush;

[0026] S5. After the nozzle is flush with the upper surface of the substrate 19, metal powder is added from the circular opening of the substrate 19 to the top of the airbag fixture 21 until the metal powder is flush with the upper surface of the substrate 19;

[0027] S6. The first, second, third, and fourth lead screw stepper motors 4, 5, 8, and 9 coordinate to control the substrate 19 to descend a set distance. The first and second lead screw stepper motors 4 and 5 coordinate to control the airbag fixture 21 to move upward a predetermined distance, applying powder and printing a support layer.

[0028] S7. Repeat step S6 until the printed support height reaches the required level.

[0029] S8. After the support printing is completed, the first screw stepper motor 4, the second screw stepper motor 5, the third screw stepper motor 8 and the fourth screw stepper motor 9 work in a coordinated manner to control the substrate 19 to descend, and powder is spread to print the curved pipe part.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The airbag fixture 21 inside the forming chamber device of the present invention uses an annular rubber airbag, which can clamp, fix and position long tube parts of different diameters. Due to the seamless clamping between the airbag and the tube wall and the use of a reducer to block the tube mouth, the downward leakage of metal powder is avoided. The height of the metal powder covering the part is much smaller than the height of the part, which saves metal powder, reduces printing costs, and facilitates the recovery of metal powder after printing.

[0032] 2. The forming chamber device of the present invention can first clamp and fix the extruded straight tube inside the forming chamber device, making full use of the internal space of the chamber and breaking the limitation of the original additive equipment on the height of the formed parts.

[0033] 3. The forming method of the present invention divides long tube parts with complex shapes into two parts and manufactures them separately. The straight tube part with large length and low precision requirement is formed by extrusion process, and the curved tube part with complex shape and high precision requirement is formed by laser powder bed melting technology, which overcomes the limitations of traditional processing technology on part shape.

[0034] 4. The forming method of the present invention first prints the support, which facilitates the cutting and separation of the printed long tube parts from the substrate during post-processing.

[0035] 5. Compared with the traditional manufacturing method of forging blank + CNC machining, the forming method of the present invention reduces material waste and shortens manufacturing time because both laser powder bed melting technology and extrusion process have the characteristics of high material utilization rate.

[0036] 6. The forming method of the present invention only uses laser powder bed melting technology to form the curved pipe part with complex shape and high precision requirements, which reduces the time share of additive manufacturing and reduces the cost of atmosphere protection for avoiding high-temperature oxidation of titanium alloy.

[0037] 7. The forming method of the present invention is not only applicable to titanium alloy parts, but also to parts made of other metal materials, and has a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of titanium alloy long tube parts.

[0039] Figure 2 1 and 2 are a front view (left) and a rear view (right) of a forming chamber device according to an embodiment of the present invention.

[0040] Figure 3 These are the left view (left) and right view (right) of the forming chamber device according to an embodiment of the present invention.

[0041] Figure 4 It is a cross-sectional view of a forming chamber device according to an embodiment of the present invention.

[0042] Figure 5 2. It is a top view of a forming chamber device according to an embodiment of the present invention.

[0043] Figure 6 1. The front view (left) and rear view (right) of the internal structure of the forming chamber device according to an embodiment of the present invention.

[0044] Figure 7 1 and 2 are a front view (left), a rear view (center), and a top view (right) of a housing 1 according to an embodiment of the present invention.

[0045] Figure 8 Schematic diagram of connecting rod 2 and connecting rod 3 according to an embodiment of the present invention.

[0046] Figure 9 Schematic diagram of connecting rod 6 and connecting rod 7 according to an embodiment of the present invention.

[0047] Figure 10 Schematic diagram of the support plate 16 according to an embodiment of the present invention.

[0048] Figure 11 Schematic diagram of a fixture guide rail body 20 according to an embodiment of the present invention.

[0049] Figure 12 Schematic diagram of the push rod 22 according to an embodiment of the present invention.

[0050] Figure 13 It is a schematic diagram of supporting printing according to an embodiment of the present invention. DETAILED DESCRIPTION

[0051] The present invention will be described in detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0052] Reference Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 and Figure 6 , a forming chamber device for additive composite manufacturing of long tube parts, including a box body 1, a base plate 19 is provided on the top of the box body 1, the base plate 19 is connected to the top of the fixture guide rail body 20 below it, the fixture guide rail body 20 is connected to the airbag fixture 21, and the airbag fixture 21 moves up and down along the fixture guide rail body 20; the left and right sides of the airbag fixture 21 are respectively connected by a first connecting rod 2, a second connecting rod 3 and a first lead screw nut 14 of a first lead screw stepper motor 4, and a second lead screw nut 15 of a second lead screw stepper motor 5, the first lead screw stepper motor 4 and the second lead screw stepper motor 5 are symmetrically connected to an annular support plate 16, and the annular support plate 16 is connected to the outer side of the middle part of the box body 1, the first lead screw stepper motor 4 coordinates to control the up and down movement of the airbag fixture 21 through the first lead screw nut 14 and the first connecting rod 2, and the second lead screw stepper motor 5 coordinates to control the up and down movement of the airbag fixture 21 through the second lead screw nut 15 and the second connecting rod 3;

[0053] The front and rear sides of the airbag clamp 21 are respectively connected to the first tracheal connector 10 and the second tracheal connector 11, and the first tracheal connector 10 and the second tracheal connector 11 are respectively connected to the first air pump 12 and the second air pump 13. The first air pump 12 and the second air pump 13 are symmetrically connected to the front and back of the box body 1 via the annular support plate 16. The first air pump 12 and the second air pump 13 inflate the airbag clamp 21 through the first tracheal connector 10 and the second tracheal connector 11 to adjust the clamping diameter and the clamping force;

[0054] The lower part of the clamp guide rail body 20 is connected to the push rod 22 located below it. The left and right sides of the push rod 22 are respectively connected by the third connecting rod 6, the fourth connecting rod 7 and the third lead screw nut 17 of the third lead screw stepper motor 8, and the fourth lead screw nut 18 of the fourth lead screw stepper motor 9. The third lead screw stepper motor 8 and the fourth lead screw stepper motor 9 are fixed to the left and right sides of the box body 1. The third lead screw stepper motor 8 and the fourth lead screw stepper motor 9 coordinate and control the up and down movement of the push rod 22 through the third lead screw nut 17 and the third connecting rod 6, the fourth lead screw nut 18 and the fourth connecting rod 7 respectively; the first lead screw stepper motor 4, the second lead screw stepper motor 5, the third lead screw stepper motor 8 and the fourth lead screw stepper motor 9 coordinate and control the up and down movement of the substrate 19.

[0055] Reference Figure 2 and Figure 3 The screw of the first screw stepper motor 4 and the first screw nut 14, and the screw of the second screw stepper motor 5 and the second screw nut 15 cooperate to form a roller screw transmission, the purpose of which is to improve the transmission accuracy, stability and service life; the screw of the third screw stepper motor 8 and the third screw nut 17, and the screw of the fourth screw stepper motor 9 and the fourth screw nut 18 cooperate to form a roller screw transmission, the purpose of which is to improve the transmission accuracy, stability and service life.

[0056] Reference Figure 2 、 Figure 3 The first trachea connector 10 is connected to the airbag clamp 21 through bolts 23, 24, 25, and 26, and the second trachea connector 11 is connected to the airbag clamp 21 through bolts 27, 28, 29, and 30. The first trachea connector 10 and the second trachea connector 11 both use rubber air tubes of sufficient length to cooperate with the up and down movement of the airbag clamp 21.

[0057] Reference Figure 4 The expansion and contraction structure of the airbag clamp 21 is an annular rubber airbag with a thickness of not less than 5 mm. After the annular rubber airbag expands and contracts, the diameter range of the outer wall of the pipe that can be clamped is 10 to 80 mm. The overall airtightness of the airbag clamp 21 is good. After expansion and contraction, it forms a ring-shaped close contact with the outer wall of the clamped pipe to prevent the downward leakage of metal powder and provide sufficient clamping force.

[0058] Reference Figure 4 、 Figure 5 The substrate 19 is a circular substrate with the same diameter as the inner wall of the box 1 and a thickness of not less than 30 mm. A circular opening 1901 with a diameter of 100 mm is opened in the middle. The circular opening 1901 is used for spreading powder before part printing. The substrate 19 can move up and down along the inner wall of the box 1. The thickness is more than 30 mm to avoid deformation of the substrate 19 during and after part printing.

[0059] Reference Figure 2 、 Figure 3 and Figure 7 The upper part of the box body 1 is provided with four windows 101, 102, 103 and 104, which serve to facilitate the installation of the first connecting rod 2, the second connecting rod 3, the first tracheal connector 10 and the second tracheal connector 11; the lower part of the box body 1 is also provided with four windows 1013, 1014, 1015 and 1016, and the front and rear windows 1015 and 1016 serve to facilitate the installation of the third connecting rod 6 and the fourth connecting rod 7, and the left and right windows 1013 and 1014 serve to limit the displacement stroke of the third connecting rod 6 and the fourth connecting rod 7.

[0060] Reference Figure 5 and Figure 7 The box body 1 has threaded holes 1017, 1018, 1019, 1020, 1021, 1022, 1023 and 1024, which are used for the third screw stepper motor 8 to be connected to the box body 1 through bolts 79, 80, 81, 82, and the fourth screw stepper motor 9 to be connected to the box body 1 through bolts 83, 84, 85, 86.

[0061] Reference Figure 2 and Figure 8 The first connecting rod 2 has threaded holes 201, 202, 203, and 204 at one end, which are connected to the first screw nut 14 through bolts 31, 32, 33, and 34; the other end of the first connecting rod 2 has threaded holes 205, 206, 207, and 208, which are connected to the airbag clamp 21 through bolts 55, 56, 57, and 58.

[0062] Reference Figure 2 and Figure 8 One end of the second connecting rod 3 is provided with threaded holes 301, 302, 303, and 304, which are connected to the second screw nut 15 through bolts 35, 36, 37, and 38; the other end of the second connecting rod 3 is provided with threaded holes 305, 306, 307, and 308, which are connected to the airbag clamp 21 through bolts 59, 60, 61, and 62.

[0063] Reference Figure 2 、 Figure 6 and Figure 9 One end of the third connecting rod 6 is provided with threaded holes 601, 602, 603, 604, 605, 606, 607, and 608, which are connected to the push rod 22 through bolts 87, 88, 89, 90, 91, 92, 93, and 94; the other end of the third connecting rod 6 is provided with threaded holes 609, 6010, 6011, and 6012, which are connected to the third lead screw nut 17 through bolts 47, 48, 49, and 50.

[0064] Reference Figure 2 、 Figure 6 and Figure 9One end of the fourth connecting rod 7 is provided with threaded holes 701, 702, 703, 704, 705, 706, 707, and 708, which are connected to the push rod 22 through bolts 95, 96, 97, 98, 99, 100, 101, and 102; the other end of the fourth connecting rod 7 is provided with threaded holes 709, 7010, 7011, and 7012, which are connected to the fourth lead screw nut 18 through bolts 51, 52, 53, and 54.

[0065] Reference Figure 2 、 Figure 5 and Figure 10 , the annular support plate 16 includes an outer flat plate and an inner vertical plate connected thereto; threaded holes 1601, 1602, 1603, 1604, 1605, 1606, 1607, 1608, 1609, 16010, 16011, 16012, 16013, 16014, 16015 and 16016 are opened on the outer flat plate, for the first screw stepper motor 4 to be fixed to the annular support plate 16 by bolts 71, 72, 73, 74, the second screw stepper motor 5 to be fixed to the annular support plate 16 by bolts 75, 76, 77, 78, the first air pump 12 to be fixed to the annular support plate 16 by bolts 67, 68, 69, 70, and the second air pump 13 to be fixed to the annular support plate 16 by bolts 63, 64, 65, 66;

[0066] The inner vertical plate of the annular support plate 16 is provided with through holes 16017, 16018, 16019, 16020, 16021, 16022, 16023 and 16024, and is connected to the outer wall of the box body 1 by bolts 39, 40, 41, 42, 43, 44, 45 and 46;

[0067] The thickness of the annular support plate 16 is not less than 20 mm to ensure sufficient rigidity.

[0068] Reference Figure 11 The clamp guide rail body 20 is provided with a guide rail inside, and the airbag clamp 21 moves up and down along the guide rail; the bottom of the clamp guide rail body 20 is provided with threaded holes 201, 202, 203 and 204 for connecting with the push rod 22; the middle part of the clamp guide rail body 20 is provided with windows 205, 206, 207 and 208, which serve to limit the displacement stroke of the first connecting rod 2, the second connecting rod 3, the first trachea connector 10 and the second trachea connector 11.

[0069] The first screw stepper motor 4 and the second screw stepper motor 5 coordinate to control the airbag clamp 21 to move up and down by a distance of 20 mm.

[0070] The first lead screw stepper motor 4 , the second lead screw stepper motor 5 , the third lead screw stepper motor 8 and the fourth lead screw stepper motor 9 coordinate to control the up and down movement distance of the substrate 19 to be 200 mm.

[0071] The precision of the first lead screw stepper motor 4 , the second lead screw stepper motor 5 , the third lead screw stepper motor 8 and the fourth lead screw stepper motor 9 is P1 level, the purpose of which is to improve the printing precision.

[0072] Reference Figure 12 The push rod 22 includes a straight rod portion and a disc portion connected to the top thereof; the straight rod portion is provided with threaded holes 2201, 2202, 2203, 2204, 2205, 2206, 2207, 2208, 2209, 22010, 22011, 22012, 22013, 22014, 22015, 22015 and 22016; the disc portion is provided with threaded holes 22017, 22018, 22019 and 22020, and the middle thereof is a cylindrical hollow through-hole with a diameter of 80 mm, which is used to place the straight tube portion of long tube parts.

[0073] The forming method of the additive composite manufacturing forming chamber device for long tubular parts comprises the following steps:

[0074] S1. Divide titanium alloy long tube parts into straight tube parts and curved tube parts;

[0075] S2. The straight pipe section with long length and low precision requirement is formed by extrusion process;

[0076] S3. Laser powder bed fusion technology is used for the complex, high-precision curved tube. The tube opening of the extruded straight tube is sealed with a reducer plug and then placed in the forming chamber. The first and second air pumps 12 and 13 operate to inflate the airbag clamp 21 until it contacts the outer wall of the straight tube and provides sufficient clamping force.

[0077] S4. The first screw stepper motor 4 and the second screw stepper motor 5 coordinate and control the movement of the airbag clamp 21 to fine-tune the nozzle so that the upper surface of the substrate 19 is flush;

[0078] S5. Reference Figure 13 After the nozzle is flush with the upper surface of the substrate 19, titanium alloy powder is added from the circular opening of the substrate 19 to the top of the airbag fixture 21 until the titanium alloy powder is flush with the upper surface of the substrate 19;

[0079] S6. The first screw stepper motor 4, the second screw stepper motor 5, the third screw stepper motor 8 and the fourth screw stepper motor 9 coordinate the control substrate 19 to drop 0.1mm, the first screw stepper motor 4 and the second screw stepper motor 5 coordinate the control airbag fixture 21 to move up 0.1mm, and a support layer is printed after the powder is applied;

[0080] S7. Repeat step S6 until the printed support height reaches 1 mm.

[0081] S8. After the support printing is completed, the first screw stepper motor 4, the second screw stepper motor 5, the third screw stepper motor 8 and the fourth screw stepper motor 9 work in a coordinated manner to control the substrate 19 to descend, and powder is spread to print the curved pipe part.

[0082] The present invention has been described in detail above with reference to the embodiments. However, the contents described are only preferred embodiments of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A method for additive manufacturing of long tubular parts, characterized by: The forming chamber device comprises a box body (1), a base plate (19) is provided at the top of the box body (1), the base plate (19) is connected to the top of the clamp guide rail body (20) below it, the clamp guide rail body (20) is connected to the airbag clamp (21), and the airbag clamp (21) moves up and down along the clamp guide rail body (20); the left and right sides of the airbag clamp (21) are respectively connected by a first connecting rod (2), a second connecting rod (3) and a first lead screw nut (14) of a first lead screw stepper motor (4), and a second lead screw nut (15) of a second lead screw stepper motor (5); the first lead screw stepper motor (4) and the second lead screw stepper motor (5) are symmetrically connected to an annular support plate (16), and the annular support plate (16) is connected to the outer side of the middle part of the box body (1); The front and rear sides of the airbag clamp (21) are respectively connected to the first air pipe connector (10) and the second air pipe connector (11), the first air pipe connector (10) and the second air pipe connector (11) are respectively connected to the first air pump (12) and the second air pump (13), and the first air pump (12) and the second air pump (13) are symmetrically connected to the front and rear of the box body (1) via the annular support plate (16); The lower portion of the fixture guide rail body (20) is connected to a push rod (22) located below the push rod (22), and the left and right sides of the push rod (22) are respectively connected through a third connecting rod (6), a fourth connecting rod (7), and a third lead screw nut (17) of a third lead screw stepper motor (8), and a fourth lead screw nut (18) of a fourth lead screw stepper motor (9). The third lead screw stepper motor (8) and the fourth lead screw stepper motor (9) are fixed to the left and right sides of the box body (1); the first lead screw stepper motor (4), the second lead screw stepper motor (5), the third lead screw stepper motor (8), and the fourth lead screw stepper motor (9) coordinate and control the up and down movement of the substrate (19); The forming method comprises the following steps: S1. Divide titanium alloy long tube parts into straight tube parts and curved tube parts; S2. The straight tube is formed by extrusion process; S3. The bent tube portion adopts laser powder bed melting technology, and the tube mouth of the straight tube formed by the extrusion process is sealed with a reducing plug, and then placed in the forming chamber device, and the first air pump (12) and the second air pump (13) work to inflate the airbag clamp (21) until the airbag clamp (21) is in close contact with the outer wall of the straight tube and provides sufficient clamping force; S4. The first screw stepper motor (4) and the second screw stepper motor (5) work in coordination to control the airbag clamp (21) to move and fine-tune so that the nozzle is flush with the upper surface of the substrate (19); S5. After the nozzle is flush with the upper surface of the substrate (19), metal powder is added from the circular opening of the substrate (19) to the top of the airbag fixture (21) until the metal powder is flush with the upper surface of the substrate (19); S6. The first screw stepper motor (4), the second screw stepper motor (5), the third screw stepper motor (8) and the fourth screw stepper motor (9) work in a coordinated manner to control the substrate (19) to descend a set distance, and the first screw stepper motor (4) and the second screw stepper motor (5) work in a coordinated manner to control the airbag fixture (21) to move up a predetermined distance, and a layer of support is printed after the powder is spread; S7. Repeat step S6 until the printed support height reaches the required level. S8. After the support printing is completed, the first screw stepper motor (4), the second screw stepper motor (5), the third screw stepper motor (8) and the fourth screw stepper motor (9) work in a coordinated manner to control the substrate (19) to descend, and the powder is spread to print the curved pipe part.

2. The forming method according to claim 1, wherein: The lead screw of the first lead screw stepper motor (4) and the first lead screw nut (14), the lead screw of the second lead screw stepper motor (5) and the second lead screw nut (15), the lead screw of the third lead screw stepper motor (8) and the third lead screw nut (17), and the lead screw of the fourth lead screw stepper motor (9) and the fourth lead screw nut (18) cooperate to form a roller screw transmission; the first lead screw stepper motor (4), the second lead screw stepper motor (5), the third lead screw stepper motor (8) and the fourth lead screw stepper motor (9) coordinate to control the up and down movement distance of the substrate (19) to be 200 mm; the precision of the first lead screw stepper motor (4), the second lead screw stepper motor (5), the third lead screw stepper motor (8) and the fourth lead screw stepper motor (9) is P1 level.

3. The forming method according to claim 1, wherein: The first trachea connector (10) and the second trachea connector (11) both use rubber trachea of ​​sufficient length to cooperate with the up and down movement of the airbag clamp (21).

4. The forming method according to claim 1, wherein: The expansion and contraction structure of the airbag clamp (21) is an annular rubber airbag with a thickness of not less than 5 mm. The diameter range of the outer wall of the pipe clamped by the annular rubber airbag after expansion and contraction is 10~80 mm. The overall airtightness of the airbag clamp (21) is good. After expansion and contraction, it forms an annular close contact with the outer wall of the clamped pipe and provides sufficient clamping force.

5. The forming method according to claim 1, wherein: The substrate (19) is a circular substrate with the same diameter as the inner wall of the box (1) and a thickness of not less than 30 mm. A circular opening (1901) is opened in the middle, and the circular opening (1901) is used for spreading powder before printing parts.

6. The forming method according to claim 1, wherein: The upper portion of the box body (1) is provided with four windows for facilitating the installation of the first connecting rod (2), the second connecting rod (3), the first tracheal connecting body (10) and the second tracheal connecting body (11); the lower portion of the box body (1) is also provided with four windows, the front and rear windows for facilitating the installation of the third connecting rod (6) and the fourth connecting rod (7), and the left and right windows for limiting the displacement stroke of the third connecting rod (6) and the fourth connecting rod (7).

7. The forming method according to claim 1, wherein: The annular support plate (16) includes an outer flat plate and an inner vertical plate connected thereto; the outer flat plate is provided with threaded holes for fixing the first screw stepper motor (4), the second screw stepper motor (5), the first air pump (12), and the second air pump (13) by bolts; the inner vertical plate is provided with through holes for being connected to the outer wall of the box body (1) by bolts; the thickness of the annular support plate (16) is not less than 20 mm to ensure sufficient rigidity.

8. The forming method according to claim 1, wherein: The fixture guide rail body (20) is provided with a guide rail inside, and the airbag fixture (21) moves up and down along the guide rail; windows are opened around the middle of the fixture guide rail body (20), which play a role in limiting the displacement stroke of the first connecting rod (2), the second connecting rod (3), the first air pipe connecting body (10) and the second air pipe connecting body (11).

9. The forming method according to claim 1, wherein: The push rod (22) comprises a straight rod portion and a disc portion connected to the top thereof; the middle of the disc portion is a cylindrical hollow through hole for placing the straight tube portion of a long tube part.

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