Multi-stage lifting forming cylinder and additive manufacturing equipment

Abstract

The utility model belongs to the technical field of additive manufacturing, and particularly relates to a multi-stage lifting forming cylinder and additive manufacturing equipment. A multi-stage lifting forming cylinder comprises a forming cylinder, an upper layer lifting mechanism and a lower layer lifting mechanism, the upper layer lifting mechanism and the lower layer lifting mechanism are located in the forming cylinder, the upper layer lifting mechanism is located above the lower layer lifting mechanism, and the upper layer lifting mechanism and the lower layer lifting mechanism are connected in series. The upper-layer lifting mechanism is of a high-precision lifting structure and has a first lifting stroke; the lower layer lifting mechanism is of a multi-stage telescopic lifting structure and has a plurality of second lifting strokes, and the first lifting stroke is smaller than or equal to the second lifting strokes. Along with the continuous increase of the height size of the formed part, only the stroke of the lower-layer lifting mechanism needs to be increased, the height size of the upper-layer lifting mechanism cannot be increased, and therefore the height space needed by the forming cylinder can be far smaller than two times of the height of the formed part, and the machining difficulty and cost of the upper-layer lifting mechanism are effectively reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of additive manufacturing, and in particular relates to a multi-stage lifting molding cylinder and additive manufacturing equipment. Background Art

[0002] Additive Manufacturing (AM) is an advanced manufacturing technology with distinctive features such as digital manufacturing, high flexibility and adaptability, direct CAD model drive, fast speed, and rich and diverse material types. Since its development in the late 1980s, it has become a pillar technology in modern advanced manufacturing technology. Selective Laser Sintering (SLS) is one of the most rapidly developing additive manufacturing technologies in recent years. The basic sintering process of the powder bed of selective laser sintering is: the powder feeding device delivers a certain amount of powder to the worktable, the powder spreading roller spreads a layer of powder material on the upper surface of the formed part of the forming cylinder, the heating device heats the powder to the set temperature, and the galvanometer system controls the laser to scan the solid part of the powder layer according to the cross-sectional profile of the layer, so that the powder melts and bonds with the formed part below; when a layer of cross section is sintered, the cylinder lifting device drops a layer of thickness, and the powder spreading roller spreads a layer of uniform and dense powder on it, and scans and sinters a new layer of cross section, and after several layers of scanning and superposition, the entire prototype manufacturing is completed.

[0003] In the above technology, the cylinder lifting device is composed of a set of high-precision lifting systems, including a spline shaft, a ball screw, a motor, etc. This type of cylinder lifting device has two main defects. First, the stroke length of the ball screw of this lifting system must be greater than or equal to the height of the molded part itself, so the height space required by the molding cylinder is at least twice the height of the molded part. As the required height of the molded part increases, the height space of the equipment increases exponentially, resulting in an increase in the cost of equipment manufacturing; second, as the required height of the molded part increases, the length of the spline shaft and the ball screw increases. Both of these parts are high-precision parts, so the processing difficulty and cost are greatly increased. Utility Model Content

[0004] The utility model provides a multi-stage lifting molding cylinder to solve the problems brought about by the existing cylinder lifting device that as the height of the required molding parts increases, the height space of the equipment increases exponentially, and the difficulty and cost of spline and ball screw processing are greatly increased.

[0005] The specific technical solutions adopted by this utility model are as follows:

[0006] A multi-level lifting forming cylinder comprises a forming cylinder, an upper lifting mechanism and a lower lifting mechanism, wherein the upper lifting mechanism and the lower lifting mechanism are located in the forming cylinder, and the upper lifting mechanism is located above the lower lifting mechanism, and the upper lifting mechanism is connected in series with the lower lifting mechanism; the upper lifting mechanism is a high-precision lifting structure, and has a first lifting stroke; the lower lifting mechanism is a multi-level telescopic lifting structure, and has multiple second lifting strokes, and the first lifting stroke is less than or equal to the second lifting stroke.

[0007] Furthermore, the movement accuracy of the upper lifting mechanism is ≤0.01mm.

[0008] Furthermore, the first lifting stroke is 50 mm to 200 mm; the second lifting stroke is 50 mm to 200 mm.

[0009] Furthermore, the upper lifting mechanism includes a screw rod, a motor, an upper base, a transmission assembly, an upper connecting plate and a guide assembly, the upper connecting plate and the upper base are arranged in parallel from top to bottom, and the upper connecting plate and the upper base are connected by the guide assembly; the lower lifting mechanism is connected to the upper base; a threaded hole matching the screw rod is provided on the upper base, the screw rod is vertically installed at the threaded hole, and the upper end of the screw rod is rotatably connected to the upper connecting plate; the motor is fixedly installed on the upper base, and the output shaft of the motor is connected to the screw rod through the transmission assembly.

[0010] Furthermore, the guide assembly includes a spline shaft, the upper base is provided with a spline hole matching the spline shaft, the spline shaft is vertically installed in the spline hole, the upper end and the lower end of the spline shaft are respectively connected to the upper connecting plate and the lower connecting plate; the number of the guide assemblies is multiple, and the multiple guide assemblies are evenly distributed around the circumference of the rotation center line of the screw rod.

[0011] Furthermore, the transmission assembly includes a nut, a gear and a gear ring, the gear is mounted on the output shaft of the motor, the gear ring is arranged on the outer surface of the nut, the nut is threadedly connected to the screw rod, and the nut is rotationally connected to the upper base, and the gear is meshed with the gear ring.

[0012] Furthermore, the lower lifting mechanism includes a lower base, a lifting body and a connecting tray which are connected in sequence, the lower base is located at the bottom of the forming cylinder and is connected to the forming cylinder, the lifting body is a multi-stage hydraulic cylinder or a multi-stage electric cylinder or a scissors lift, and the connecting tray is connected to the upper base.

[0013] An additive manufacturing device, comprising the multi-stage lifting molding cylinder, further comprising:

[0014] A sintering substrate, the sintering substrate is located above the upper lifting mechanism and connected to the upper lifting mechanism, and the sintering substrate is used to receive the printed molded parts;

[0015] A powder spreader, which is used to spread a powder layer on the sintering surface of the sintered substrate or the formed part;

[0016] A laser galvanometer system emits laser and selectively scans and sintered the powder layer.

[0017] An additive manufacturing method using the additive manufacturing device comprises the following steps:

[0018] S1: The lower lifting mechanism rises, and the upper lifting mechanism rises, so that the sintering surface of the sintered substrate reaches the scanning molding surface position;

[0019] S2: Start sintering. During sintering, the lower lifting mechanism remains stationary. Each time a layer is sintered, the upper lifting mechanism drops one layer accordingly until one movement stroke is completed. Figure 5 Status shown;

[0020] S3: The lower lifting mechanism descends one stroke, driving the molded parts and the upper lifting mechanism to descend one stroke, so that the sintering surface of the molded parts is one stroke lower than the scanning molding surface, see Figure 6 Status shown;

[0021] S4: The upper lifting mechanism rises a stroke to make the sintering surface of the molded part coincide with the scanning molding surface, see Figure 7 Status shown;

[0022] S5: Repeat steps S2-S4 until the sintering of the entire molded part is completed.

[0023] Furthermore, the movement stroke is less than or equal to the first lifting stroke, and the movement stroke is 50mm-200mm.

[0024] The utility model provides a multi-level lifting molding cylinder and additive manufacturing equipment, wherein the multi-level lifting molding cylinder is composed of two sets of lifting structures connected in series in the height direction, the upper lifting mechanism is a set of high-precision lifting structure, having a first lifting stroke; the lower lifting mechanism is a set of ordinary multi-level telescopic lifting structure, having multiple second lifting strokes, wherein the first lifting stroke is less than or equal to the second lifting stroke. When the molded parts are sintered, the lower lifting mechanism first remains stationary, and the upper lifting mechanism first participates in the layer-by-layer sintering. When the number of sintering layers reaches a movement stroke, the upper lifting mechanism suspends sintering, the lower lifting mechanism descends a movement stroke, and then the upper lifting mechanism carries the sintered parts back up a movement stroke, and continues to start sintering, and this is repeated until the entire prototype manufacturing is completed, wherein the movement stroke is less than or equal to the first lifting stroke. The utility model ensures the sintering accuracy of the formed parts through the high-precision lifting structure of the upper layer, and the multi-stage telescopic lifting structure has a large elongation and a small contraction height, and can achieve a large telescopic ratio. Therefore, the required height dimension of the formed parts is ensured by the multi-stage telescopic lifting structure of the lower layer. As the height dimension of the formed parts continues to increase, it can be achieved by simply increasing the stroke of the lower lifting mechanism, and the height dimension of the upper lifting mechanism will not increase. The lower lifting mechanism is a multi-stage telescopic lifting structure, so the height space required for the forming cylinder can be much less than twice the height of the formed parts. Compared with the existing cylinder lifting device, the space in the height direction of the equipment can be greatly reduced, and the processing difficulty and cost of the upper lifting mechanism are effectively reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 This is a schematic diagram of the structure of the multi-stage lifting molding cylinder of the utility model;

[0027] Figure 2 This is a structural schematic diagram of the upper lifting mechanism of the utility model;

[0028] Figure 3 This is a structural schematic diagram of the lower lifting mechanism of the utility model;

[0029] Figure 4 Schematic diagram of the state of the additive manufacturing equipment of the utility model during sintering;

[0030] Figure 5 Schematic diagram of the state of the additive manufacturing equipment of the utility model during sintering;

[0031] Figure 6 Schematic diagram of the state of the additive manufacturing equipment of the utility model during sintering;

[0032] Figure 7 Schematic diagram of the state of the additive manufacturing equipment of the utility model during sintering.

[0033] The above reference numerals:

[0034] 100. Upper lifting mechanism; 200. Lower lifting mechanism; 1. Sintering substrate; 2. Upper connecting plate; 3. Upper base; 4. Lower connecting plate; 5. Screw; 6. Motor; 7. Spline shaft; 8. Connecting tray; 9. Lifting body; 10. Forming cylinder; 11. Lower base; 12. Laser galvanometer system. DETAILED DESCRIPTION

[0035] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively with reference to the accompanying drawings. The accompanying drawings provide preferred embodiments of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0036] like Figure 1-3 As shown, the present embodiment provides a multi-stage lifting forming cylinder, comprising a forming cylinder 10, an upper lifting mechanism 100 and a lower lifting mechanism 200, wherein the upper lifting mechanism 100 and the lower lifting mechanism 200 are located in the forming cylinder 10, and the upper lifting mechanism 100 is located above the lower lifting mechanism 200, and the upper lifting mechanism 100 is connected in series with the lower lifting mechanism 200; the upper lifting mechanism 100 is a high-precision lifting structure, having a first lifting stroke; the lower lifting mechanism 200 is a multi-stage telescopic lifting structure, having a plurality of second lifting strokes, wherein the first lifting stroke is less than or equal to the second lifting stroke.

[0037] In this embodiment, the motion accuracy of the upper lifting mechanism 100 is preferably ≤ 0.01 mm. The motion accuracy specifically refers to the motion accuracy of the upper lifting mechanism 100 during the lifting process to ensure the accuracy of sintering of the formed parts. Preferably, the motion accuracy of the upper lifting mechanism 100 is 0.01 mm, 0.008 mm or 0.0005 mm, etc.

[0038] In this embodiment, the sintering accuracy of the molded parts is ensured by the upper lifting mechanism 100, and the lower lifting mechanism 200 only needs to ensure the height dimension required for the sintering of the molded parts. Therefore, the multi-stage telescopic lifting structure adopted by the lower lifting mechanism 200 does not need to meet the high motion accuracy required by the upper lifting mechanism 100. When the lower lifting mechanism 200 completes a second lifting stroke, it only needs to ensure that it can accurately reach the starting and ending positions corresponding to a second lifting stroke. This requirement is easier to meet for the existing multi-stage telescopic lifting technology, so the manufacturing cost of the lower lifting mechanism 200 can be effectively reduced.

[0039] In this embodiment, the first lifting stroke is 50mm~200mm. Specifically, the first lifting stroke can be 50mm, 60mm, 80mm, 100mm, 120mm, 150mm, 200mm, etc., and of course it can also be a non-integer value; the second lifting stroke is 50mm~200mm; specifically, the second lifting stroke can be 50mm, 60mm, 80mm, 100mm, 120mm, 150mm, 200mm, etc., and of course it can also be a non-integer value.

[0040] Preferably, in this embodiment, the first lifting stroke and the second lifting stroke are equal, and preferably are 100 mm, and the corresponding height dimension of the upper lifting mechanism 100 is small, which can effectively reduce the processing difficulty and cost of the upper lifting mechanism 100.

[0041] This embodiment also provides an additive manufacturing device, including the multi-stage lifting molding cylinder, and further comprising:

[0042] A sintering substrate 1, the sintering substrate 1 is located above the upper lifting mechanism 100 and connected to the upper lifting mechanism 100, and the sintering substrate 1 is used to receive the printed molded parts;

[0043] A powder spreader, which is used to spread a powder layer on the sintering surface of the sintered substrate 1 or the formed part;

[0044] The laser galvanometer system 12 emits laser and selectively scans and sinter the powder layer.

[0045] See also Figure 4-7 As shown, an additive manufacturing method using the additive manufacturing device comprises the following steps:

[0046] S1: The lower lifting mechanism 200 rises, and the upper lifting mechanism 100 rises, so that the sintering surface of the sintered substrate 1 reaches the scanning molding surface position, see Figure 4 Status shown;

[0047] S2: Sintering starts. During sintering, the lower lifting mechanism 200 remains stationary. Each time a layer is sintered, the upper lifting mechanism 100 is lowered by one layer until a movement stroke is completed. Figure 5 Status shown;

[0048] S3: The lower lifting mechanism 200 moves down by one stroke, driving the molded part and the upper lifting mechanism 100 to move down by one stroke, so that the sintering surface of the molded part is one stroke lower than the scanning molding surface, see Figure 6 Status shown;

[0049] S4: The upper lifting mechanism 100 moves up a stroke so that the sintering surface of the molded part coincides with the scanning molding surface. Figure 7 Status shown;

[0050] S5: Repeat steps S2-S4 until the sintering of the entire molded part is completed.

[0051] In this embodiment, the movement stroke is less than or equal to the first lifting stroke, and the movement stroke is 50mm-200mm. Specifically, the movement stroke can be 50mm, 60mm, 80mm, 100mm, 120mm, 150mm, 200mm, etc., and of course, it can also be a non-integer value. The movement stroke is preferably 100mm.

[0052] In this embodiment, the movement stroke is preferably equal to the first lifting stroke, and the second lifting stroke is equal to the first lifting stroke. Therefore, in the corresponding step S1: the lower lifting mechanism 200 rises to its upper limit position, and the upper lifting mechanism 100 rises to its upper limit position; in the corresponding step S2: when sintering is completed for one movement stroke, the upper lifting mechanism 100 descends to its lower limit position; in the corresponding step S4: when the upper lifting mechanism 100 rises for one movement stroke, the upper lifting mechanism 100 rises to its upper limit position.

[0053] In this embodiment, before each layer is sintered, the powder spreader first spreads the powder layer on the sintering substrate 1 or the sintering surface of the formed part. During sintering, the laser galvanometer system 12 emits laser and selectively scans and sinters the powder layer. This is a conventional technology for additive manufacturing, so it is not described in detail. The laser galvanometer system 12 is in the on state during sintering, and the laser galvanometer system 12 is in the off state in step S1, step S3 and step S4.

[0054] The present embodiment provides a multi-stage lifting molding cylinder, additive manufacturing equipment and additive manufacturing method, wherein the multi-stage lifting molding cylinder is composed of two sets of lifting structures connected in series in the height direction, the upper lifting mechanism 100 is a set of high-precision lifting structure, having a first lifting stroke; the lower lifting mechanism 200 is a set of ordinary multi-stage telescopic lifting structure, having multiple second lifting strokes, wherein the first lifting stroke is less than or equal to the second lifting stroke. When the molded parts are sintered, the lower lifting mechanism 200 first remains stationary, and the upper lifting mechanism 100 first participates in the layer-by-layer sintering. When the number of sintering layers reaches a movement stroke, the upper lifting mechanism 100 suspends sintering, the lower lifting mechanism 200 descends a movement stroke, and then the upper lifting mechanism 100 carries the sintered parts and rises a movement stroke to continue sintering, and this is repeated until the entire prototype manufacturing is completed, wherein the movement stroke is less than or equal to the first lifting stroke. In this embodiment, the sintering accuracy of the molded parts is ensured by the high-precision lifting structure of the upper layer, and the height of the molded parts is ensured by the multi-stage telescopic lifting structure of the lower layer. As the height of the molded parts continues to increase, it can be achieved by increasing the stroke of the lower lifting mechanism 200, and the height of the upper lifting mechanism 100 will not increase, so that the height space required by the molding cylinder 10 can be much smaller than twice the height of the molded parts. Compared with the existing cylinder lifting device, the space in the height direction of the equipment is greatly reduced, and the processing difficulty and cost of the upper lifting mechanism 100 are effectively reduced.

[0055] See also Figure 1 and 2 As shown, in this embodiment, preferably, the upper lifting mechanism 100 includes a screw rod 5, a motor 6, an upper base 3, a transmission assembly, an upper connecting plate 2, a lower connecting plate 4 and a guide assembly, wherein the upper connecting plate 2, the upper base 3 and the lower connecting plate 4 are arranged in parallel and alternately from top to bottom, and the upper connecting plate 2, the upper base 3 and the lower connecting plate 4 are connected through the guide assembly; the lower lifting mechanism 200 is connected to the upper base 3; the upper base 3 is provided with a threaded hole matched with the screw rod 5, the screw rod 5 is vertically installed at the threaded hole, and the upper end and the lower end of the screw rod 5 are rotatably connected with the upper connecting plate 2 and the lower connecting plate 4 respectively; the motor 6 is fixedly installed on the upper base 3, and the output shaft of the motor 6 is connected to the screw rod 5 through the transmission assembly. The motor 6 and the transmission assembly are located between the upper base 3 and the lower connecting plate 4.

[0056] In this embodiment, a frame structure is formed between the upper base 3, the upper connecting plate 2 and the lower connecting plate 4, and the structure is stable and reliable. The lifting and lowering guide function of the upper lifting mechanism 100 is realized by the guide assembly to ensure the lifting and lowering motion accuracy. In this embodiment, preferably, the screw rod 5 is a ball screw rod.

[0057] When the lower lifting mechanism 200 of this embodiment remains stationary, the upper base 3 remains stationary because the lower lifting mechanism 200 is connected to the upper base 3. When the upper lifting mechanism 100 is lifted or lowered, the motor 6 is started to drive the screw 5 to rotate through the transmission assembly. Since the upper base 3 remains stationary, the upper connecting plate 2 and the lower connecting plate 4 are driven to move up and down under the spiral transmission of the screw 5 and the threaded hole. The sintering substrate 1 is located above the upper lifting mechanism 100 and is connected to the upper lifting mechanism 100. Specifically, the sintering substrate 1 is connected to the upper connecting plate 2. Therefore, when the upper connecting plate 2 and the lower connecting plate 4 are lifted or lowered, the sintering substrate 1 is driven to move up and down, thereby realizing the lifting and lowering movement of the upper lifting mechanism 100.

[0058] When sintering layer by layer through a movement stroke, the lower lifting mechanism 200 descends through a movement stroke. Since the lower lifting mechanism 200 is connected to the upper base 3, the descent of the lower lifting mechanism 200 will synchronously drive the molded parts and the upper lifting mechanism 100 to descend through a movement stroke.

[0059] In this embodiment, the guide assembly preferably includes a spline shaft 7, a spline hole matching the spline shaft 7 is provided on the upper base 3, the spline shaft 7 is vertically installed in the spline hole, and the upper end and the lower end of the spline shaft 7 are respectively connected to the upper connecting plate 2 and the lower connecting plate 4; the number of the guide assemblies is multiple, and the multiple guide assemblies are evenly distributed around the circumference of the rotation center line of the screw rod 5. Under the action of the spline shaft 7 and the spline hole, the guiding function is realized, and the guiding precision is high.

[0060] In this embodiment, the transmission assembly preferably includes a nut, a gear and a gear ring, the gear is mounted on the output shaft of the motor 6, the gear ring is disposed on the outer surface of the nut, the nut is threadedly connected to the screw rod 5, and the nut is rotationally connected to the upper base 3, and the gear is meshed with the gear ring. When the upper lifting mechanism 100 is lifted or lowered, the motor 6 starts to drive the gear to rotate, the gear rotation drives the nut to rotate through the gear ring, and the nut is rotationally connected to the upper base 3, so the nut rotates on the upper base 3. Since the upper base 3 remains stationary, the rotation of the nut will drive the screw rod 5 to rotate, and the screw rod 5 rotates, thereby driving the upper connecting plate 2 and the lower connecting plate 4 to perform lifting and lowering movements.

[0061] See also Figure 1 and 3As shown, in this embodiment, preferably, the lower lifting mechanism 200 includes a lower base 11, a lifting body 9 and a connecting tray 8 which are connected in sequence, the lower base 11 is located at the bottom of the forming cylinder 10 and is connected to the forming cylinder 10, the lifting body 9 is a multi-stage hydraulic cylinder or a multi-stage electric cylinder or a scissor lift, and the connecting tray 8 is connected to the upper base 3. A through hole is provided on the lower connecting plate 4 to facilitate the connection tray 8 to pass through the through hole and connect to the upper base 3, thereby realizing the connection between the lower lifting mechanism 200 and the upper base 3. In this embodiment, the lifting body 9 is not limited to the existing multi-stage hydraulic cylinder or multi-stage electric cylinder or scissor lift, and other existing multi-stage telescopic lifting structures can also be used.

[0062] The above shows and describes the basic principle, main features and advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments. The above embodiments and descriptions are only for explaining the principle of the utility model. The utility model may have various changes and improvements without departing from the spirit and scope of the utility model. These changes and improvements fall within the scope of the utility model to be protected. The scope of protection claimed by the utility model is defined by the attached claims and their equivalents.

Claims

1. A multi-stage lifting forming cylinder, characterized in that: The invention comprises a molding cylinder (10), an upper lifting mechanism (100) and a lower lifting mechanism (200), wherein the upper lifting mechanism (100) and the lower lifting mechanism (200) are located in the molding cylinder (10), and the upper lifting mechanism (100) is located above the lower lifting mechanism (200), and the upper lifting mechanism (100) and the lower lifting mechanism (200) are connected in series; the upper lifting mechanism (100) is a high-precision lifting structure and has a first lifting stroke; the lower lifting mechanism (200) is a multi-stage telescopic lifting structure and has a plurality of second lifting strokes, wherein the first lifting stroke is less than or equal to the second lifting stroke.

2. The multi-stage lifting forming cylinder according to claim 1, characterized in that: The movement accuracy of the upper lifting mechanism (100) is ≤0.01 mm.

3. The multi-stage lifting forming cylinder according to claim 1, characterized in that: The first lifting stroke is 50 mm to 200 mm; the second lifting stroke is 50 mm to 200 mm.

4. The multi-stage lifting forming cylinder according to claim 1, characterized in that: The upper lifting mechanism (100) comprises a screw rod (5), a motor (6), an upper base (3), a transmission assembly, an upper connecting plate (2), a lower connecting plate (4) and a guide assembly. The upper connecting plate (2), the upper base (3) and the lower connecting plate (4) are arranged in parallel and spaced from top to bottom, and the upper connecting plate (2), the upper base (3) and the lower connecting plate (4) are connected via the guide assembly. The lower lifting mechanism (200) is connected to the upper base (3). The upper base (3) is provided with a threaded hole matching the screw rod (5); the screw rod (5) is vertically mounted at the threaded hole, and the upper end and the lower end of the screw rod (5) are rotatably connected to the upper connecting plate (2) and the lower connecting plate (4) respectively; the motor (6) is fixedly mounted on the upper base (3), and the output shaft of the motor (6) is connected to the screw rod (5) through the transmission assembly.

5. The multi-stage lifting forming cylinder according to claim 4, characterized in that: The guide assembly comprises a spline shaft (7), the upper base (3) is provided with a spline hole matched with the spline shaft (7), the spline shaft (7) is vertically installed in the spline hole, and the upper end and the lower end of the spline shaft (7) are respectively connected to the upper connecting plate (2) and the lower connecting plate (4); the number of the guide assemblies is multiple, and the multiple guide assemblies are evenly distributed around the circumference of the rotation center line of the screw rod (5).

6. The multi-stage lifting forming cylinder according to claim 4, characterized in that: The transmission assembly comprises a nut, a gear and a gear ring, wherein the gear is mounted on the output shaft of the motor (6), the gear ring is arranged on the outer surface of the nut, the nut is threadedly connected to the screw rod (5), and the nut is rotationally connected to the upper base (3), and the gear is meshed with the gear ring.

7. The multi-stage lifting forming cylinder according to claim 4, characterized in that: The lower lifting mechanism (200) comprises a lower base (11), a lifting body (9) and a connecting tray (8) which are connected in sequence, wherein the lower base (11) is located at the bottom of the forming cylinder (10) and is connected to the forming cylinder (10), the lifting body (9) is a multi-stage hydraulic cylinder or a multi-stage electric cylinder or a scissor lift, and the connecting tray (8) is connected to the upper base (3).

8. An additive manufacturing device, characterized in that: The multi-stage lifting forming cylinder according to any one of claims 1 to 7 further comprises: A sintering substrate (1), the sintering substrate (1) being located above the upper lifting mechanism (100) and connected to the upper lifting mechanism (100), the sintering substrate (1) being used to receive printed molded parts; A powder spreader, the powder spreader being used to spread a powder layer on the sintering substrate (1) or the sintering surface of a formed part; A laser galvanometer system (12) emits laser light and selectively performs scanning sintering on the powder layer.

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