Screening speed control device for 3D printing sand mold

Abstract

The invention relates to a screening speed control device for a 3D printing sand mold. The screening speed control device comprises a feeding barrel, a separating and grinding cover is arranged below the feeding barrel, a material distributing column body is rotationally arranged in the separating and grinding cover, a plurality of sets of material guiding pipes are arranged in the material distributing column body, the two ends of each material guiding pipe penetrate through the material distributing column body, and a screen is arranged above the material guiding pipes. One strand of materials is divided into a plurality of strands of materials through the material guide pipes in the material distribution column body, sand grains needed by printing are evenly spread into the material guide pipes, fluctuation of the materials in the material guide pipes is neutralized, and therefore fluctuation of the total material supply amount is reduced, and uniformity and continuity of the total material supply amount are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of mold printing, and specifically refers to a screening and speed control device for 3D printing sand molds. Background Art

[0002] 3D printing sand molds is a relatively efficient sand mold manufacturing process. When printing sand molds, it is crucial to ensure the uniformity and fluidity of sand grains. If the sand grains cannot flow continuously or flow unevenly, it is impossible to ensure the uniformity of subsequent layer-by-layer sand laying (the single-layer thickness requirement of the sand layer is between 0.2 - 0.5 mm), resulting in unevenness on the surface of the sand mold. If the sizes of the sand grains are not uniform, it will clog the nozzle, affect the fluidity of the sand grains, have an impact on the single-layer thickness of the sand layer, and reduce the printing efficiency and quality.

[0003] During sand mold printing, a centralized feeding method is often used to collect and convey all sand grains to the 3D printing head, forming a single conveying channel. Therefore, it is crucial to ensure the uniformity of sand grain flow in the single conveying channel. However, during actual material conveyance, there are differences in the total amount of materials at different positions in the conveying channel, and differences in the sizes of material particles at different positions, which will all cause feeding fluctuation problems and affect the uniformity and fluidity of sand grains. Summary of the Invention

[0004] In view of the above situation, to overcome the defects of the prior art, the present invention provides a screening and speed control device for 3D printing sand molds, which solves at least some of the above problems.

[0005] The technical solution adopted by the present invention is as follows: A screening and speed control device for 3D printing sand molds proposed by the present invention includes a feeding cylinder arranged vertically. A feeding screw is rotatably arranged inside the feeding cylinder. A separation and grinding cover is arranged below the feeding cylinder. A material distribution cylinder is rotatably arranged inside the separation and grinding cover. A plurality of guide pipes are arranged inside the material distribution cylinder. Both ends of the guide pipe penetrate through the material distribution cylinder. A screen is arranged above the guide pipe.

[0006] Further, in order to separate the screened large-sized sand grains, the separation and grinding cover includes a first cone, and the first cone is arranged below the feeding cylinder.

[0007] Further, in order to prevent sand grains from splashing, an outer shield is arranged outside the first cone, and there is a gap between the outer shield and the first cone; Further, in order to recycle and process the separated large-sized sand grains, a second cone is arranged below the first cone. The second cone is fixedly arranged at the lower end of the outer shield, and a recovery cylinder is arranged at the lower end of the second cone.

[0008] Further, in order to grind and crush the recycled sand grains again to meet the usage requirements, a grinding conical plate is provided in the middle of the material distribution column body. The grinding conical plate is arranged close to the second cone, and the grinding conical plate is not parallel to the second cone.

[0009] Further, in order to drive the material distribution column body to rotate, a driven wheel is provided on the material distribution column body. A driving wheel is engaged with the driven wheel, and a motor is fixed on the driving wheel.

[0010] Further, the lower end of the feed cylinder has the same slope as the first cone, so as to leave a certain gap between the lower end of the feed cylinder and the first cone, and this gap is adjustable; Further, in order to adjust the gap between the feed cylinder and the first cone, a first support plate is provided on the outer side of the separation and grinding cover. A second support plate is provided on the outer side wall of the feed cylinder. A plurality of groups of distance-adjusting screws are penetrated through the second support plate, and the ends of the distance-adjusting screws are threadedly connected to the first support plate.

[0011] Further, a spring is wound around the distance-adjusting screw, and the spring is connected between the first support plate and the second support plate.

[0012] Further, a recovery pipe is provided on the side wall of the recovery cylinder. A delivery pump is connected to the recovery pipe, and the discharge port of the delivery pump is connected to the feed cylinder.

[0013] Further, a central protrusion is provided at the center of the upper wall of the material distribution column body. The upper end opening of the guide pipe is between the first cone and the central protrusion.

[0014] Further, the guide pipe includes an inclined pipe. The opening of the inclined pipe is flush with the upper wall of the material distribution column body, and the center line of the inclined pipe intersects with the upper wall of the material distribution column body.

[0015] Further, in order to tamp the materials in the guide pipe to make the materials more uniform and continuous, a spiral pipe is provided at the lower end of the inclined pipe. The spiral pipe is spirally arranged downward in the material distribution column body.

[0016] Further, a converging pipe is provided at the lower end of the spiral pipe. The lower end opening of the converging pipe is flush with the lower wall of the material distribution column body, and the converging pipe is converged towards the center direction of the material distribution column body.

[0017] The beneficial effects achieved by the present invention are as follows: The guide pipes arranged in an array within the material distribution column can divide the required materials into several strands, approximately evenly distributing the amount of sand grains required for printing per unit time into each guide pipe. There are fluctuations in the quantity of materials within each guide pipe, and the fluctuations of the materials in multiple guide pipes tend to neutralize each other, thereby reducing the fluctuations in the overall feeding quantity and enhancing the uniformity and continuity of the total feeding quantity. Moreover, the first cone on the separation and grinding cover, in cooperation with the screen, can separate and grind large sand grains, thereby enhancing the uniformity of the material particles and further enhancing the uniformity of the material flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 FIG. is a schematic structural diagram of a screening and speed control device for 3D printing sand molds according to Embodiment 1 of the present invention; Figure 2 FIG. is a schematic distribution diagram of the guide pipes at the bottom of the material distribution column; Figure 3 FIG. is a cross-sectional view of an embodiment of the present invention; Figure 4 FIG. is a positional relationship diagram of the material distribution column, the separation and grinding cover, and the guide pipes; Figure 5 FIG. is a schematic structural diagram of the separation and grinding cover; Figure 6 is Figure 3 an enlarged view of part I in Figure 7 FIG. is a schematic structural diagram of the guide pipe.

[0019] Among them, 1. material distribution column, 2. separation and grinding cover, 3. feeding cylinder, 4. feeding screw, 5. delivery pump, 6. driven wheel, 7. driving wheel, 8. motor, 9. first support plate, 10. second support plate, 11. distance adjustment screw, 12. spring, 13. guide pipe, 14. screen, 15. grinding cone plate, 16. central protrusion, 17. first cone, 18. outer shield, 19. second cone, 20. recovery cylinder, 21. recovery pipe, 22. inclined pipe, 23. spiral pipe, 24. converging pipe.

[0020] The drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation to the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments; based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0022] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0023] As Figures 1 - 3 As shown, a screening speed control device for a 3D printing sand mold includes a feed cylinder 3 arranged in the vertical direction. A feeding screw 4 is rotatably arranged in the feed cylinder 3, and the feeding screw 4 is driven by an external power mechanism (not shown in the drawings). A separation and grinding cover 2 is arranged below the feed cylinder 3. A material distribution cylinder 1 is rotatably arranged in the separation and grinding cover 2. A plurality of guide pipes 13 are arranged in the material distribution cylinder 1. Preferably, the guide pipes 13 are arranged in a circumferential array, and both ends of the guide pipes 13 penetrate through the material distribution cylinder 1 (in some embodiments, it is set as the guide pipes 13. In actual production, in order to solve the assembly problem, the guide pipes 13 can be directly formed in the material distribution cylinder 1 by 3D printing); a screen 14 is arranged above the guide pipes 13. When the sand particle material is spirally pushed downward under the action of the feeding screw 4, the sand particle material will be screened by the screen 14, and large particle impurities will be screened out. The sand particles meeting the diameter will penetrate through the screen 14 and enter the guide pipes 13, and the number of materials entering each guide pipe 13 will be adapted to the pipe diameter, so that the sand particle consumption required for printing per unit time is approximately evenly distributed into each guide pipe 13. There are certain fluctuations in the number of materials in each guide pipe 13. When the number of guide pipes 13 is large, the fluctuations of the materials in each guide pipe 13 will gradually tend to be neutralized, thereby improving the uniformity and continuity of the sand particle material feeding and avoiding large fluctuations or interruption phenomena when feeding through a single pipe.

[0024] As Figure 4 and Figure 5 As shown, in order to separate the screened large particle sand grains, the separation and grinding cover 2 includes a first cone 17. The first cone 17 is arranged below the feed cylinder 3. The opening radius of the upper part of the first cone 17 is larger than that of the lower part, so that the first cone 17 presents a horn shape with an upward opening. The large particle sand grains are intercepted by the screen 14 and have a certain rotational kinetic energy under the action of the feeding screw 4. Under the action of centrifugal force, they are gradually stratified from the small particle sand grains and move outward and upward along the inner wall slope of the first cone 17, thus completing the separation operation.

[0025] In order to prevent sand grains from splashing, an outer shield 18 is arranged outside the first cone 17, and there is a gap between the outer shield 18 and the first cone 17; In order to recycle and process the separated large granular sand grains, a second conical body 19 is provided below the first conical body 17, and the tapered spaces between the first conical body 17 and the second conical body 19 are both arranged downward. The second conical body 19 is fixedly arranged at the lower end of the outer shield 18. The outer shield 18 connects the first conical body 17 and the second conical body 19. A recovery cylinder 20 is provided at the lower end of the second conical body 19. The separated sand grains fall into the recovery cylinder 20 through the gap between the outer shield 18 and the first conical body 17.

[0026] As Figure 3 and Figure 6 shown, in order to grind and crush the recycled sand grains again to meet the usage requirements, a grinding conical plate 15 is provided in the middle of the material distribution column body 1. The grinding conical plate 15 is arranged close to the second conical body 19, and the grinding conical plate 15 is not parallel to the second conical body 19. A relatively small gap is reserved at the position close to the intersection of the two. Only the sand grains meeting the size requirements can pass through this gap. When the large granular materials reach between the grinding conical plate 15 and the second conical body 19, they will be gradually squeezed into finer granular shapes as the material distribution column body 1 rotates.

[0027] As Figure 1 and Figure 3 shown, in order to drive the material distribution column body 1 to rotate, a driven wheel 6 is provided on the material distribution column body 1. A driving wheel 7 is engaged with the driven wheel 6, and a motor 8 is fixed on the driving wheel 7.

[0028] When the sand grains rotate under the action of the feeding screw 4, not only the large granular sand grains will break away from the first conical body 17, but also some small granular materials will be thrown out from the first conical body 17. In order to reduce the loss of small granular sand grains, the lower end of the feeding cylinder 3 has the same slope as the first conical body 17, so that a certain gap is reserved between the lower end of the feeding cylinder 3 and the first conical body 17, and this gap is adjustable; In order to adjust the gap between the feeding cylinder 3 and the first conical body 17, a first support plate 9 is provided on the outer side of the separation and grinding cover 2, a second support plate 10 is provided on the outer side wall of the feeding cylinder 3, and a plurality of groups of distance adjusting screws 11 are penetrated through the second support plate 10. The end of the distance adjusting screw 11 is threadedly connected to the first support plate 9. When the distance adjusting screw 11 is rotated, the distance adjusting screw 11 will move up and down relative to the first support plate 9, thereby driving the second support plate 10 to move up and down. The second support plate 10 drives the feeding cylinder 3 to move up and down, and finally changes the gap between the lower end of the feeding cylinder 3 and the first conical body 17.

[0029] A spring 12 is wound around the distance adjusting screw 11. The spring 12 is connected between the first support plate 9 and the second support plate 10. The spring 12 always pushes the first support plate 9 and the second support plate 10 in opposite directions, so that the frictional force at the threaded engagement of the distance adjusting screw 11 and the first support plate 9 is greater, making the distance adjusting screw 11 more stable and preventing the distance between the first support plate 9 and the second support plate 10 from changing due to the vibration of the device.

[0030] In order to re - convey the sand grains after being re - processed back into the feeding cylinder 3, a recovery pipe 21 is provided on the side wall of the recovery cylinder 20. A delivery pump 5 is connected to the recovery pipe 21, and the discharge port of the delivery pump 5 is connected to the feeding cylinder 3. The delivery pump 5 continuously sucks out the sand grains in the recovery cylinder 20 and then pumps them into the feeding cylinder 3.

[0031] As Figure 3 and Figure 4 shown, in order to make the sand grains disperse more quickly into the surrounding guide pipes 13, a central protrusion 16 is provided at the center of the upper wall of the distribution column body 1. The upper - end opening of the guide pipe 13 is located between the first cone 17 and the central protrusion 16. Under the action of the central protrusion 16, a groove - shaped space is formed between the central protrusion 16 and the first cone 17. The sand grains will not stay at the center of the upper wall of the distribution column body 1, but will converge at the opening of the guide pipe 13 under the action of gravity and centrifugal force, so that the material can better enter the guide pipe 13.

[0032] As Figure 7 shown, in order to further promote the rapid entry of sand grains into the guide pipe 13, the guide pipe 13 includes an inclined pipe 22. The opening of the inclined pipe 22 is flush with the upper wall of the distribution column body 1. The center line of the inclined pipe 22 intersects with the upper wall of the distribution column body 1. The inclined direction of the inclined pipe 22 is opposite to the rotation direction of the feeding screw 4. The sand grains rotate along with the direction of the feeding screw 4, and the inclined direction of the inclined pipe 22 is the same as the rotation direction of the distribution column body 1. That is, the opening of the inclined pipe 22 will move relative to the sand grains. When the inclined pipe 22 rotates, it will quickly take the sand grains into the pipe.

[0033] In order to tamp the material in the guide pipe 13 and make the material more uniform and continuous, a spiral pipe 23 is provided at the lower end of the inclined pipe 22. The spiral pipe 23 is spirally arranged downward in the distribution column body 1. When the spiral pipe 23 rotates along with the distribution column body 1, the material in the spiral pipe 23 moves spirally, thus generating a gyroscopic effect. The gyroscopic effect makes the movement of the sand - grain material more stable and uniform, ensuring the more reliable conveyance of the material in the distribution column body 1, making the continuous conveyance of the material between the materials and avoiding a fault.

[0034] A converging pipe 24 is provided at the lower end of the spiral pipe 23. The lower - end opening of the converging pipe 24 is flush with the lower wall of the distribution column body 1. The converging pipe 24 is arranged to converge towards the center of the distribution column body 1, so as to collect all the materials in the guide pipes 13 and make them enter the print head.

[0035] The specific working principle is as follows: The sand - grain material is placed in the feeding cylinder 3. The feeding screw 4 rotates under the action of an external power mechanism and drives the sand - grain material to rotate. The sand - grain material rotates and moves downward onto the distribution column body 1. At this time, the sand - grain material has a certain rotational kinetic energy.

[0036] When the sand particles reach the central protrusion 16, they will quickly move outward and will not accumulate in the central area of the material distribution column 1. The large-sized sand particles cannot penetrate the screen 14 and will continue to stay on the screen 14, while the small-sized sand particles will penetrate the screen 14 and fall into the lower guide pipe 13.

[0037] The retained large-sized sand particles move outward under the action of centrifugal force and climb upward and outward along the surface of the first cone 17 until they are blocked by the outer shield 18 and fall off. The fallen particles enter the gap between the grinding cone plate 15 and the second cone 19. When the motor 8 is started, the grinding cone plate 15 on the material distribution column 1 is driven to rotate through the driving wheel 7 and the driven wheel 6, so as to crush the sand particles in the gap between the grinding cone plate 15 and the second cone 19 to make their sizes meet the requirements, and then they fall into the lower recovery cylinder 20 and are transported to the feed cylinder 3 by the transfer pump 5 to participate in the operation again.

[0038] After the sand particles that meet the size requirements penetrate the screen 14, they will first enter the inclined pipe 22. The inclined pipe 22 rotates in the opposite direction to the sand particles and can quickly incorporate the sand particles. After the sand particles enter the inclined pipe 22, they will rotate with the material distribution column 1. When the sand particles reach the spiral pipe 23, they will move downward in a spiral manner, generating a gyroscopic effect, so that the flow of the material in the guide pipe 13 is more continuous and uniform. The sand particles continue to move downward into the converging pipe 24 and converge toward the center following the direction of the converging pipe 24 for subsequent entry into the print head.

[0039] During use, if it is necessary to reduce the loss of sand particles during feeding, that is, to reduce the number of sand particles separated outward from the first cone 17, it can be achieved by rotating the distance-adjusting screw 11. When the distance-adjusting screw 11 rotates, it will change the distance between the second support plate 10 and the first support plate 9, thereby changing the height of the feed cylinder 3 and finally changing the distance between the bottom end of the feed cylinder 3 and the first cone 17.

[0040] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0041] The above description is made on the present invention and its implementation manners. Such description is not restrictive. What is shown in the drawings is only one of the implementation manners of the present invention, and the actual structure is not limited thereto. Generally speaking, if those of ordinary skill in the art are inspired by it and, without departing from the gist of the present invention creation, design structurally similar ways and embodiments to this technical solution without creative efforts, they shall fall within the protection scope of the present invention.

Claims

1. A screening speed control device for a 3D printing sand mold, comprising a feed barrel (3), wherein a feed screw (4) is rotatably arranged in the feed barrel (3), characterized in that: Also includes: A separation grinding cover (2) comprises a first cone (17) and a second cone (19), wherein the first cone (17) is arranged below the feed barrel (3), the inner side wall of the first cone (17) has a slope, the second cone (19) is arranged below the first cone (17), and the cones of the first cone (17) and the second cone (19) are both arranged downward; A material distribution column (1) is rotatably disposed in a separation grinding cover (2), wherein a plurality of material guide tubes (13) are disposed in the material distribution column (1), and both ends of the material guide tubes (13) penetrate the material distribution column (1); A screen (14) is arranged above the material guide pipe (13) and is used to screen sand particles; The grinding cone plate (15) is arranged in the middle of the material distribution column (1) and is arranged close to the second cone (19) at an angle.

2. The screening speed control device for 3D printing sand mold according to claim 1, characterized in that: An outer baffle (18) is provided on the outer side of the first cone (17), a gap is left between the outer baffle (18) and the first cone (17), the second cone (19) is fixedly arranged at the lower end of the outer baffle (18), and a recovery cylinder (20) is provided at the lower end of the second cone (19).

3. The screening speed control device for 3D printing sand mold according to claim 2, characterized in that: A recovery pipe (21) is provided on the side wall of the recovery cylinder (20), a delivery pump (5) is connected to the recovery pipe (21), and an outlet of the delivery pump (5) is connected to the feed cylinder (3).

4. The screening speed control device for 3D printing sand mold according to claim 1, characterized in that: The material distributing column (1) is provided with a driven wheel (6), the driven wheel (6) is meshed with a driving wheel (7), and a motor (8) is fixed to the driving wheel (7).

5. The screening speed control device for 3D printing sand mold according to claim 1, characterized in that: A first support plate (9) is provided on the outer side of the separation grinding cover (2), and a second support plate (10) is provided on the outer side wall of the feed barrel (3). A plurality of sets of pitch-adjusting screws (11) are penetrated through the second support plate (10), and the ends of the pitch-adjusting screws (11) are threadedly connected to the first support plate (9). A spring (12) is provided around the pitch-adjusting screws (11), and the spring (12) is connected between the first support plate (9) and the second support plate (10).

6. The screening speed control device for 3D printing sand mold according to claim 5, characterized in that: The lower end of the feed barrel (3) has the same slope as the first cone (17), and the pitch-adjusting screw (11) is capable of adjusting the gap between the lower end of the feed barrel (3) and the first cone (17).

7. The screening speed control device for 3D printing sand mold according to claim 1, characterized in that: A central protrusion (16) is provided at the centre of the upper wall of the material distribution column (1), and the upper end opening of the material guide tube (13) is located between the first cone (17) and the central protrusion (16).

8. The screening speed control device for 3D printing sand mold according to claim 1, characterized in that: The material guide pipe (13) comprises an inclined tube (22), the opening of the inclined tube (22) is flush with the upper wall of the material distribution column (1), and the center line of the inclined tube (22) is arranged to intersect with the upper wall of the material distribution column (1).

9. The screening speed control device for 3D printing sand mold according to claim 8, characterized in that: A spiral tube (23) is provided at the lower end of the inclined tube (22), and the spiral tube (23) is spirally arranged downward in the material distribution column (1).

10. The screening speed control device for 3D printing sand mold according to claim 9, characterized in that: A gathering tube (24) is provided at the lower end of the spiral tube (23), the lower end opening of the gathering tube (24) is flush with the lower wall of the material distribution column (1), and the gathering tube (24) is gathered towards the center of the material distribution column (1).

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