A lifting device

Abstract

The application provides a lifting device, which comprises a lifting support for mounting a printing substrate, the lifting support comprises an upper support, a lower support and guide rods, wherein the upper support and the lower support are connected through the guide rods, and the guide rods are circumferentially and uniformly distributed at two-thirds of the radius of the upper support; the upper support of the lifting support is arranged in the inner cavity of a powder cylinder assembly, and the upper support and the powder cylinder assembly are sealingly and slidably connected; the device is used in an EBSM device, is responsible for realizing accurate lifting of a workbench, and enables the printing substrate on the workbench to be kept accurate and horizontal during lifting, thereby laying a foundation for efficient, uniform and accurate compaction printing of metal powder on a powder bed.

Description

Technical Field

[0001] This invention belongs to the field of 3D printing, and specifically relates to a lifting device. Background Technology

[0002] Electron beam selective melting (EBSM) is a metal 3D printing technology that uses an electron beam as an energy source to manufacture solid parts by melting metal powder layer by layer in a high vacuum environment. Due to the high power of the electron beam and the high energy absorption rate of the material, EBSM technology offers advantages such as high part density, low oxygen content, low thermal stress, resistance to deformation and cracking, low cost of powder consumables, recyclability of unfinished powder, and high printing efficiency. It possesses unique advantages and application value in the 3D printing of metal materials, especially refractory and difficult-to-machine metals, and is widely used in fields such as orthopedic medicine and aerospace.

[0003] The EBSM (Electron Beam Semiconductor) process is as follows: First, a layer of powder is spread on a powder-spreading plane; then, under computer control, an electron beam selectively melts the powder according to the cross-sectional profile. The metal powder is melted together under the bombardment of the electron beam and adheres to the already formed part below, layer by layer, until the entire part is completely melted; finally, excess powder is removed to obtain the desired three-dimensional product. The real-time scanning signal from the host computer is transmitted to the deflection coil after digital-to-analog conversion and power amplification. The electron beam is deflected under the magnetic field generated by the corresponding deflection voltage, achieving selective melting.

[0004] The EBSM forming chamber must be in a high vacuum to ensure normal operation of the equipment. When using EBSM technology for production, it is necessary to consider minimizing the size of the vacuum chamber and the evacuation time to avoid a bulky vacuum system. Therefore, it is important to focus on the issue of compact structure, and the mechanism should be arranged outside the vacuum chamber as much as possible.

[0005] Meanwhile, whether the powder is spread evenly directly determines the precision and quality of the molded parts. Therefore, improving the horizontal precision of the printed surface is an urgent problem to be solved.

[0006] Existing lifting devices for EBSM equipment rarely consider ensuring the horizontal accuracy of the worktable throughout its entire stroke. The shortcomings of existing lifting device technology are:

[0007] (1) Most worktables cannot guarantee the horizontal accuracy of the entire stroke, resulting in insufficient accuracy of the printed parts;

[0008] (2) The lack of precision in calculations results in a non-compact structure;

[0009] (3) Lack of optimized design for precision key components results in bulky parts;

[0010] (4) Lack of precision breakdown; precision should be implemented throughout the entire process of design, parts manufacturing, selection of purchased parts, testing, installation and commissioning.

[0011] (5) There is no effective calculation method for vacuum seals, especially dynamic seals. Summary of the Invention

[0012] The purpose of this invention is to provide a lifting device that solves the above-mentioned shortcomings of existing lifting devices used for printing substrates in electron beam selective melting equipment.

[0013] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0014] The present invention provides a lifting device, including a lifting bracket for mounting a printing substrate. The lifting bracket includes an upper bracket, a lower bracket and guide rods, wherein the upper bracket and the lower bracket are connected by a plurality of guide rods, and the plurality of guide rods are evenly distributed circumferentially at two-thirds of the radius of the upper bracket.

[0015] The upper support of the lifting bracket is placed inside the cavity of the powder cylinder assembly, and the two are connected in a sealed sliding connection. Preferably, the powder cylinder assembly includes a cylinder and a cylinder bottom, wherein the cylinder bottom is a cylindrical structure, and its open end is fitted onto one end of the cylinder; the bottom of the cylinder bottom has multiple mounting holes, which cooperate with guide rods; the upper support is placed inside the cylinder.

[0016] Preferably, a sealing assembly is provided between each of the mounting holes and the guide rod.

[0017] Preferably, the sealing assembly includes a bushing, one end of which is provided with a bushing flange, the bushing flange is mounted on the cylinder bottom, and sealing rings are provided between the bushing flange and the cylinder bottom, and between both ends of the bushing and the guide rod.

[0018] Preferably, both ends of the bushing are provided with pressure caps for adjusting the sealing ring.

[0019] Preferably, an air extraction hole is provided on the side wall of the bushing.

[0020] Preferably, the lower support is equipped with a transmission component for driving the support bracket to move up and down.

[0021] Preferably, the transmission assembly includes a motor, a reducer, a small pulley, a large pulley, a toothed belt, a lead screw, and a lead screw nut. One end of the lead screw is fixedly connected to the bottom of the powder cylinder assembly, and the other end is rotatably connected to the lead screw nut fixedly mounted on the lower support. The large pulley is fitted onto the lead screw nut near the lower support. The large pulley is connected to the small pulley via the toothed belt, and the small pulley is driven by the reducer and the output shaft of the motor.

[0022] Preferably, the bottom sidewall of the powder cylinder assembly is further provided with an auxiliary guide rail assembly for assisting in guiding the support bracket.

[0023] Preferably, the auxiliary guide rail assembly includes a guide rail pair and a guide rail bracket, wherein two guide rail brackets are provided, one end of each guide rail bracket is fixedly installed on the side wall of the cylinder bottom, and a guide rail pair is installed on each of the two guide rail brackets, and the guide rail pair is slidably connected to the lower bracket.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] This invention provides a lifting device for use in a 2x2 array electron beam selective melting (EBSM) equipment. This device is responsible for precisely lifting the worktable, ensuring the printing substrate remains precisely horizontal during the lifting process. This lays the foundation for the efficient, uniform, and precise spreading and compaction of metal powder onto the powder bed for printing. Specifically:

[0026] (1) The required level accuracy of the worktable surface can be achieved during continuous lifting and lowering;

[0027] (2) The present invention provides a novel guide structure with additional guide rails, which effectively reduces the deformation caused by tilting and twisting of the worktable surface;

[0028] (3) Because the present invention adopts a relatively special guide rod vacuum sealing method, the vacuum level is guaranteed, so that printing can proceed smoothly;

[0029] (4) The transmission part of this invention has a simple and compact structure and is located outside the vacuum chamber, saving vacuum chamber space. This saves vacuuming time, and the vacuum system does not need to be very large, thus significantly reducing equipment cost;

[0030] (5) The lifting lower support is optimized through mechanical simulation design calculation to ensure that its strength and stiffness accurately meet the requirements, so as to avoid wasting materials and ensure the operating accuracy of the mechanism;

[0031] (6) The transmission part and the screw nut are installed on the lower bracket and rise and fall together with it. The screw nut rotates along the fixed screw.

[0032] (7) This device adopts a vertical fixing scheme with the upper end of the screw fixed and the lower end free, which is conducive to bearing large loads. The screw pair transmits the load in the vertical direction to the screw support structure. The support structure - the bottom of the powder cylinder - is optimized to stably fix the screw and distribute the load.

[0033] (8) This device uses helical motion to transmit the load, which has high stability and can ensure the stable transmission of the load and improve the motion accuracy.

[0034] (9) The screw is easy to install. Simply install the screw on the support structure - the bottom of the powder cylinder. Attached Figure Description

[0035] Figure 1 This is a structural diagram of the lifting device;

[0036] Figure 2 This is a sectional view of the lifting device;

[0037] Figure 3 This is a schematic diagram of the lifting support structure;

[0038] Figure 4 This is a schematic diagram of the sealing assembly structure;

[0039] Figure 5 This is a schematic diagram of the transmission assembly structure;

[0040] Figure 6 This is a structural diagram of the transmission assembly;

[0041] Among them, 1. Lifting bracket; 2. Powder cylinder assembly; 3. Sealing assembly; 4. Transmission assembly; 5. Auxiliary guide rail assembly; 11. Upper bracket; 12. Guide rod; 13. Lower bracket; 21. Cylinder barrel; 22. Cylinder bottom; 31. Bushing; 32. First pressure cover; 33. Second pressure cover; 34. Sealing ring; 35. Dust cover; 41. Reducer; 42. Small pulley; 43. Large pulley; 44. Toothed belt; 45. Lead screw; 46. Lead screw nut; 51. Guide rail bracket; 52. Guide rail pair. Detailed Implementation

[0042] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0043] Example 1

[0044] This embodiment provides a lifting device, including a lifting bracket 1, a powder cylinder assembly 2, a sealing assembly 3, a transmission assembly 4, and an auxiliary guide rail assembly 5, wherein:

[0045] The upper end of the lifting bracket 1 is placed in the inner cavity of the powder cylinder assembly 2, and the two are slidably connected.

[0046] The upper end of the lifting bracket 1 and the powder cylinder assembly 2 are sealed together by a sealing assembly 3.

[0047] The transmission component 4 is driven to connect with the lifting bracket 1.

[0048] The auxiliary guide rail assembly 5 is installed on the outside of the lifting bracket 1 and is used to provide auxiliary guidance for the lifting bracket 1.

[0049] The upper end of the powder cylinder assembly 2 is inserted into the molding chamber of the EBSM equipment and is fixedly installed in the molding chamber through the cylinder flange.

[0050] Because part of the device's structure is located outside the molding chamber, ordinary materials can be used, and it is not limited by the vacuum environment; at the same time, the molding chamber is small in size and has few internal components, which is conducive to rapid vacuuming.

[0051] Example 2

[0052] Based on Embodiment 1, the lifting assembly 1 involved in this embodiment includes an upper support 11, a lower support 13 and guide rods 12, wherein the upper support 11 and the lower support 13 are connected by a plurality of guide rods 12, and the plurality of guide rods 12 are evenly distributed along the circumference.

[0053] The lower support 13 includes a column with a fan-shaped cross-section. A first groove is formed on one end face of the column, and a second groove is formed on the other end face of the column.

[0054] An installation hole is provided at the center of the column.

[0055] The multiple guide rods 12 are evenly distributed along the circumferential direction at the bottom of the first groove.

[0056] The multiple guide rods 12 are positioned at two-thirds of the radius of the upper support 11, which can effectively reduce the deformation of the upper support 11 and ensure its levelness during operation.

[0057] The upper support 11 is placed in the inner cavity of the powder cylinder assembly 2.

[0058] Example 3

[0059] Based on Example 1, the powder cylinder assembly 2 involved in this example includes a cylinder barrel 21 and a cylinder bottom 22, wherein one end of the cylinder bottom 22 is fitted onto one end of the cylinder barrel 21.

[0060] The cylinder bottom 22 includes a bottom plate, and a ring of axially arranged side plates is provided along the edge of the bottom plate. This structure gives it sufficient rigidity to ensure that the guide rail bracket installed on it deforms little and meets the accuracy requirements.

[0061] The bottom plate of the cylinder bottom 22 has multiple mounting holes, and a linear bearing is installed in each mounting hole. The multiple linear bearings cooperate with multiple guide rods 12 one by one to realize the vertical sliding connection between the guide rods 12 and the cylinder bottom 22. The fitting accuracy between the linear bearings and the guide rods 12 is a key component to ensure the motion accuracy.

[0062] The auxiliary guide rail assembly 5 is installed on the side plate of the cylinder bottom 22.

[0063] The upper support is placed inside the cylinder 21.

[0064] A sealing assembly 3 is provided between each mounting hole and the guide rod.

[0065] Example 4

[0066] Based on Embodiment 1, the sealing assembly 3 involved in this embodiment includes a bushing 31, a sealing ring 34, a first gland 32, a second gland 33, and a dust cover 35, wherein:

[0067] An air extraction hole is provided on the side wall of the bushing 31.

[0068] The upper end of the bushing 31 is provided with a bushing flange, which is fixedly installed at the bottom of the cylinder.

[0069] A sealing ring is provided between the bushing flange and the cylinder bottom.

[0070] A second pressure cap 33 is installed on the upper end face of the bushing, and a first pressure cap 32 is installed on the lower end face of the bushing.

[0071] The bushing flange is threaded with a dust cover 35.

[0072] The dust cover 35, the first pressure cover 32 and the second pressure cover 33 are all provided with a central through hole, which is arranged coaxially with the central through hole of the bushing 31.

[0073] The sealing component 3 is mounted on the guide rod 12.

[0074] Both ends of the bushing 31 are provided with sealing rings 34 between them and the guide rod. The sealing rings 34 achieve radial air sealing and play a role in isolating vacuum. The use of double sealing rings 34 increases the sealing effect. During installation, the tightening amount of the sealing caps 32 and 33 is adjusted to make the sealing rings 34 achieve a satisfactory sealing effect and ensure the vacuum degree in the powder cylinder.

[0075] Example 5

[0076] Based on Embodiment 1, the transmission component 4 involved in this embodiment includes a motor, a reducer 41, a small pulley 42, a large pulley 43, a toothed belt 44, a lead screw 45, and a lead screw nut 46. One end of the lead screw 45 is fixedly connected to the cylinder bottom 22, and the other end is inserted into the lower bracket 13 and rotatably connected to the lead screw nut 46. The lead screw 45 is fixedly connected to the large pulley 43, and the large pulley 43 is connected to the small pulley 42 through the toothed belt 44. The small pulley 42 is mounted on the output shaft of the reducer 41.

[0077] The output shaft of the motor is connected to the reducer 41, and both the motor and the reducer are mounted on the side wall of the lower bracket 13.

[0078] Both the large pulley 43 and the small pulley 42 are installed in the second groove.

[0079] The nut 46 is fixedly connected to the lower bracket 13.

[0080] Example 6

[0081] Based on Embodiment 1, the auxiliary guide rail assembly involved in this embodiment includes a guide rail pair 52 and a guide rail bracket 51. There are two guide rail brackets 51, one end of each guide rail bracket 51 is fixedly installed on the side wall of the cylinder bottom 22, and a guide rail pair 52 is installed on each of the two guide rail brackets 51. The guide rail pair 52 is slidably connected to the lower bracket 13.

[0082] The purpose of this application is to improve existing electron beam selective melting (EBSM) manufacturing technology to adapt to the rapid manufacturing of precision and complex parts. The focus is on providing a novel, high-precision device to address the accuracy issues of the lifting mechanism. The device has a printing table size of Φ660mm and a stroke of 830mm, meeting the requirement that the maximum formable size of the EBSM equipment can be Φ660mm×750mm, with a maximum lifting speed of 0.5m / min.

[0083] The advantages of this application are:

[0084] (1) The required level accuracy of the worktable surface can be achieved during continuous lifting and lowering;

[0085] (2) The present invention provides a novel guide structure with additional guide rails, which effectively reduces the deformation caused by tilting and twisting of the worktable surface;

[0086] (3) Because the present invention adopts a relatively special guide rod vacuum sealing method, the vacuum level is guaranteed, so that printing can proceed smoothly;

[0087] (4) The transmission part of the present invention has a simple and compact structure and is located outside the vacuum chamber, saving vacuum chamber space and thus saving vacuuming time. The vacuum system does not need to be very large, so the equipment cost can be greatly reduced.

[0088] (5) The lifting lower support is optimized through mechanical simulation design calculation to ensure that its strength and stiffness accurately meet the requirements, so as to avoid wasting materials and ensure the operating accuracy of the mechanism;

[0089] (6) The transmission part and the screw nut are installed on the lower bracket and rise and fall together with it. The screw nut rotates along the fixed screw.

[0090] (7) This device adopts a vertical fixing scheme with the upper end of the screw fixed and the lower end free, which is conducive to bearing large loads. The screw pair transmits the load in the vertical direction to the screw support structure. The support structure - the bottom of the powder cylinder - is optimized to stably fix the screw and distribute the load.

[0091] (8) This device uses helical motion to transmit the load, which has high stability and can ensure the stable transmission of the load and improve the motion accuracy.

[0092] (9) The screw is easy to install. Simply install the screw on the support structure - the bottom of the powder cylinder.

[0093] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A lifting device, characterized in that The application relates to a lifting support (1) for mounting a printing substrate, which comprises an upper support (11), a lower support (13) and guide rods (12), wherein the upper support (11) and the lower support (13) are connected by the guide rods (12) which are evenly distributed at two-thirds of the radius of the upper support (11) in a circumferential direction. The upper support (11) of the lifting support (1) is arranged in the inner cavity of a powder cylinder assembly (2) and is in sealed sliding connection with the powder cylinder assembly (2); the powder cylinder assembly comprises a cylinder barrel (21) and a cylinder bottom (22), wherein the cylinder bottom (22) is in a cylindrical structure, the open end of the cylinder bottom (22) is sleeved at one end of the cylinder barrel (21), a plurality of mounting holes are formed in the bottom of the cylinder bottom (22) and are matched with the guide rods, the upper support (11) is arranged in the cylinder barrel (21), a sealing assembly is arranged between each mounting hole and the guide rod, the sealing assembly comprises a shaft sleeve (31), one end of the shaft sleeve (31) is provided with a shaft sleeve flange, the shaft sleeve flange is arranged on the cylinder bottom (22), and a sealing ring (34) is arranged between the shaft sleeve flange and the cylinder bottom and between the two ends of the shaft sleeve and the guide rods.

2. A lifting device according to claim 1, characterised in that The two ends of the shaft sleeve are provided with gland nuts for adjusting the sealing rings.

3. A lifting device according to claim 1, characterised in that A suction hole is formed in the sidewall of the shaft sleeve (31).

4. A lifting device according to claim 1, characterised in that A transmission assembly for driving the support support to move up and down is arranged on the lower support.

5. A lifting device according to claim 4, characterised in that The transmission assembly comprises a motor, a speed reducer (41), a small pulley (42), a large pulley (43), a toothed belt (44), a lead screw (45) and a nut (46), wherein one end of the lead screw (45) is fixedly connected with the cylinder bottom (22) of the powder cylinder assembly, the other end is rotationally connected with the nut (46) fixedly arranged on the lower support, the large pulley (43) is sleeved on the nut close to the lower support, the large pulley (43) is connected with the small pulley (42) through the toothed belt (44), and the small pulley (42) is drivingly connected with the output shaft of the motor through the speed reducer (41).

6. A lifting device according to claim 1, wherein An auxiliary guide rail assembly for assisting the guide of the support support is further arranged on the sidewall of the cylinder bottom of the powder cylinder assembly.

7. A lifting device according to claim 6, characterised in that The auxiliary guide rail assembly comprises a guide rail pair (52) and a guide rail support (51), wherein two guide rail supports (51) are arranged, one end of each of the two guide rail supports (51) is fixedly arranged on the sidewall of the cylinder bottom (22), one guide rail pair (52) is arranged on each of the two guide rail supports (51), and the guide rail pair (52) is in sliding connection with the lower support (13).

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