Sand paving device

Abstract

The invention discloses a sanding device, which belongs to the technical field of 3D printing, and comprises symmetrically arranged mounting seats, a knife edge plate assembly arranged between the two seats, and a central shaft assembly connected with the two ends of a knife edge plate. At least one end of the knife edge plate assembly is provided with a containing cavity, and an eccentric assembly extending into the cavity is correspondingly installed on the installation base. A movable space is formed between the eccentric assembly and the cavity wall and can make contact with the cavity wall during rotation, and the knife edge plate is driven to swing around the center shaft at high frequency and slight amplitude. According to the design, eccentric driving is integrated at the end of the knife edge plate, exciting force is evenly transmitted in the length direction of the knife edge through swinging, and the problems of power desynchrony and middle attenuation possibly occurring in traditional double-side driving are effectively solved. The vibration of the knife edge plate effectively improves the leveling property and the filling density of sand grains, so that a sand layer is smoother and more compact. And meanwhile, sand adhesion can be reduced through the swing action of the knife edge plate when the knife edge plate leaves the area where sand is laid, the phenomenon of sand dragging or sand adhering is remarkably restrained, and the sand laying quality and the continuity of printing operation are guaranteed.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of 3D printing, and particularly relates to a sand spreading device. BACKGROUND

[0002] In the 3D printing industry, especially in the 3D printing technology based on binder jetting, the precision and stability of the sand spreading device directly determine the layer thickness uniformity and the final quality of the formed part. The existing sand spreading device usually adopts a knife edge structure made of a whole beam. Due to the too large span of the integral long knife edge, it is prone to deformation under long-term working load, which makes it difficult to ensure the sand spreading flatness and affects the printing precision. At the same time, the too long knife edge also brings significant machining problems, resulting in high manufacturing cost and low yield. In terms of sand spreading power transmission, it generally relies on bilateral external vibrators. The excitation force from both ends to the middle is attenuated and out of sync during transmission, resulting in uneven distribution of sand particles in the length direction of the knife edge and unsatisfactory sand spreading effect. In addition, the structure often appears "sand dragging" or "sand sticking" phenomenon during sand spreading, that is, when the knife edge leaves the spreaded sand surface, part of the sand particles are abnormally taken away, which destroys the integrity of the spreaded sand surface and seriously affects the continuity of the printing process and the reliability of the formed part. These defects jointly restrict the production efficiency and forming quality of the 3D printing equipment. SUMMARY

[0003] (I) Invention purpose In order to overcome the above shortcomings, the purpose of the present application is to provide a sand spreading device to solve the technical problems that the existing sand spreading device adopts an integral long knife edge which is prone to deformation and an external vibrator with low efficiency, resulting in uneven sand spreading, frequent sand dragging, and seriously affecting the precision and stability of 3D printing.

[0004] (II) Technical scheme In order to achieve the above purpose, the technical scheme provided by the present application is as follows: A sand spreading device, comprising: two symmetrical mounting seats, a knife edge plate assembly arranged between the two mounting seats, the knife edge plate assembly being provided with a receiving cavity at least at one end, two center shaft assemblies arranged on the two mounting seats respectively and rotationally connected with the end portions of the knife edge plate assembly at both ends, and an eccentric assembly arranged on at least one mounting seat and extending into the receiving cavity at the corresponding end, the eccentric assembly and the receiving cavity forming an activity space and being tangent to the inner wall of the receiving cavity when rotating to drive the knife edge plate assembly to swing around the center shaft assembly.

[0005] By directly integrating the eccentric drive mechanism at the end of the knife edge plate assembly and utilizing its swing principle, the excitation force is more directly and uniformly transmitted in the length direction of the knife edge, effectively avoiding the problem of power asynchronization and intermediate attenuation that may occur in traditional external double-sided drive. This driving mode, combined with the swing motion of the knife edge plate, can produce continuous and uniform high-frequency micro-vibration on the sand particles during the sanding process, significantly improving the leveling and filling density of the sand particles, and thus obtaining a more flat and dense sand layer. At the same time, the swing action of the knife edge plate when leaving the sanded surface helps to reduce the adhesion of sand particles to the knife edge, fundamentally inhibiting the occurrence of "dragging sand" or "sticking sand" phenomenon, and ensuring the integrity of the sanded surface and the continuity of the printing process.

[0006] In some embodiments, the knife edge plate assembly comprises a long strip-shaped support beam, a knife edge plate arranged on the support beam, and two guide seats arranged at the two ends of the support beam, respectively, wherein the guide seat is provided with the accommodating cavity.

[0007] By adopting the split combination structure of the knife edge plate and the guide seat, the knife edge plate can focus on the sanding function, simplifying its structure and reducing the processing and manufacturing difficulty and cost of the long strip-shaped knife edge plate. The guide seat can be a standard part or a more easily processed component, which is specially optimized to accommodate the driving component and realize swing guiding, improving the rationality and processability of the structure. This modular design not only facilitates independent processing and precision control of each component, but also facilitates subsequent maintenance and replacement. If the knife edge plate is worn out, only this part needs to be replaced, effectively reducing maintenance costs.

[0008] In some embodiments, the center shaft assembly comprises a center shaft fixed at one end on the two mounting seats and a first bearing arranged at the other end of the center shaft, and the first bearing is rotatably connected with the end of the knife edge plate assembly.

[0009] The combination of the center shaft and the first bearing provides a stable, low-friction and precise rotation center for the knife edge plate assembly. This fulcrum design ensures that the knife edge plate assembly can smoothly and reliably reciprocate around a fixed axis, and its swing trajectory is stable and controllable, avoiding unnecessary shaking or deviation, thereby ensuring the consistency of the knife edge motion trajectory during sanding. The stable swing center combined with the eccentric drive makes the transmission efficiency of the driving force and the swing kinetic energy converted higher, which helps to enhance the effect of vibration sanding. At the same time, the bearing connection reduces wear under long-term operation, prolongs the service life of the device, and ensures the persistence of motion accuracy.

[0010] In some embodiments, the eccentric component includes: a motor fixed on a mounting base, a second bearing disposed on the mounting base corresponding to the position of the motor, a connecting shaft with one end passing through the second bearing and connected to the motor, and an eccentric wheel connected to the other end of the connecting shaft and extending into a receiving cavity, wherein the connecting shaft is connected to the non-central position of the eccentric wheel.

[0011] The motor, acting as the power source, directly transmits torque to the eccentric wheel via a connecting shaft, resulting in a short power transmission path and minimal energy loss. The rotation of the eccentric wheel within the receiving cavity generates periodic centrifugal force, which is converted into a tangential force driving the knife-edge plate assembly to swing through its contact with the cavity's inner wall. This built-in excitation method concentrates vibration energy more directly onto the knife-edge plate, significantly improving vibration efficiency and uniformity, ensuring that sand particles along the entire length of the knife-edge plate are effectively excited and fully leveled. Compared to external vibrators, this structure effectively solves the problems of asynchronous and attenuated excitation force transmission, resulting in a more uniform sand density. Simultaneously, the motor's speed and torque are easily controlled, facilitating adjustments to the vibration intensity and frequency according to different sand materials and layer thickness requirements, enhancing the device's adaptability and intelligence.

[0012] In some embodiments, the blade plate includes multiple interconnected blade plate segments.

[0013] The multi-segment connected cutterhead design is an effective way to solve the problem of easy deformation in long-span structures. It breaks down the originally monolithic, easily bent cutterhead into multiple shorter segments. The rigidity and straightness of each segment are more easily guaranteed, thus significantly reducing the risk of structural deformation due to self-weight or working stress. This ensures higher flatness and straightness of the cutterhead along its entire length, providing a fundamental guarantee for the smoothness of the sand-laying. Furthermore, the segmented structure greatly reduces the machining difficulty of individual parts and the risk of deformation during heat treatment, improving the yield and accuracy of finished products. During on-site maintenance, if a local cutterhead segment is damaged, it is not necessary to replace the entire cutterhead; only the damaged segment needs to be replaced, greatly reducing maintenance complexity and cost, and improving the economic efficiency of the equipment. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the sand-laying device of the present invention; Figure 2 This is the invention Figure 1 Cross-sectional view of the sand-laying device along direction AA; Figure 3 This is the invention Figure 1 Cross-sectional view of the sand-laying device in the BB direction.

[0015] Figure label: 1, mounting seat; 2, knife edge plate assembly; 201, knife edge plate; 2011, knife edge plate segment; 202, guide seat; 2021, accommodating cavity; 203, support beam; 3, central shaft assembly; 301, central shaft; 302, first bearing; 4, eccentric assembly; 401, motor; 402, second bearing; 403, connecting shaft; 404, eccentric wheel. DETAILED DESCRIPTION

[0016] In order to make the objectives, technical solutions and advantages of the present application clearer, further detailed description will be made to the present application with specific embodiments and in reference to the drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present application. In addition, in the following description, the description of well-known structures and technologies will be omitted to avoid unnecessary confusion of the concept of the present application.

[0017] The present application provides a sanding device, which comprises: two mounting seats 1 arranged symmetrically, which are usually fixed on the base frame of the sanding equipment by bolts or welding to ensure overall stability. Further, a knife edge plate assembly 2 is arranged between the two mounting seats 1, which is designed with an accommodating cavity 2021 at least at one end, i.e. the end portion forms a cavity structure. In particular, two central shaft assemblies 3 arranged on the two mounting seats 1 are connected to the two end portions of the knife edge plate assembly 2 by rotating connection, so that the knife edge plate assembly 2 can swing around the central shaft assembly 3. In addition, an eccentric assembly 4 is installed on at least one mounting seat 1, which extends into the corresponding end accommodating cavity 2021. A certain clearance is reserved between the eccentric assembly 4 and the accommodating cavity 2021, and when the eccentric assembly 4 rotates, the outer edge thereof can periodically tangent to the inner wall of the accommodating cavity 2021, thereby driving the knife edge plate assembly 2 to swing around the central shaft assembly 3 at high frequency. Preferably, the mounting seat 1 is made of a metal plate with a thickness of about 10 mm to enhance rigidity, and the knife edge plate assembly 2 can be made of wear-resistant alloy steel material, so that the design not only ensures the structural strength, but also effectively improves the sanding uniformity through the built-in swing mechanism.

[0018] Further, the knife edge plate assembly 2 comprises: an elongated support beam 203, a knife edge plate 201 arranged below the support beam 203, and two guide seats 202 fixed at the two ends of the knife edge plate 201 respectively. The guide seat 202 is internally provided with the above-mentioned accommodating cavity 2021 for accommodating part of the structure of the eccentric assembly 4. Preferably, the knife edge plate 201 and the guide seat 202 are assembled by bolt connection or plug-in connection, which is convenient for disassembly and maintenance. In particular, the knife edge plate 201 can be made as a whole or a segmented structure according to actual needs, for example, a segmented design is adopted in longer span applications to reduce the risk of deformation. In this way, such a modular layout simplifies the processing technology and improves the flexibility and maintainability of assembly.

[0019] Specifically, the knife-edge plate segments 2011 are designed as follows: The knife-edge plate 201 comprises a plurality of knife-edge plate segments 2011 connected with each other. The knife-edge plate segments 2011 are sequentially installed on the support beam 203 by connecting members such as bolts or buckle structures, and are integrally formed into a long strip. Preferably, the knife-edge plate segments 2011 are made of the same material such as tool steel, and each segment has a length that can be customized according to the processing conditions, for example, about 500 mm per segment, so as to reduce the processing deformation. In particular, alignment grooves or positioning pins are arranged at the connection positions of the segments, so as to ensure the flatness after splicing. It is worth noting that this segmented design not only reduces the manufacturing difficulty and cost of the long knife-edge, but also facilitates local replacement and maintenance, thereby prolonging the service life of the device and improving the economy.

[0020] On this basis, the central shaft assembly 3 comprises a central shaft 301 fixed at one end to the two mounting seats 1 and a first bearing 302 arranged at the other end of the central shaft 301. The first bearing 302 is rotationally connected with the end of the knife-edge plate assembly 2, so that the knife-edge plate assembly 2 can smoothly swing about the central shaft 301 as the fulcrum. Preferably, the central shaft 301 is made of high-strength steel material, and the first bearing 302 is selected from deep groove ball bearings or sliding bearing types, so as to reduce the friction loss. Further, the central shaft 301 is fixed to the mounting seat 1 by screwing or press-fitting, so as to ensure the connection reliability. It is worth noting that this rotational support structure provides a stable swing axis for the knife-edge plate assembly 2, thereby guaranteeing the accuracy and consistency of the sand laying action.

[0021] In particular, the eccentric assembly 4 comprises a motor 401 fixed to the mounting seat 1, a second bearing 402 arranged on the mounting seat 1 corresponding to the position of the motor 401, a connecting shaft 403 penetrating the second bearing 402 at one end and connected with the output shaft of the motor 401, and an eccentric wheel 404 connected with the other end of the connecting shaft 403 and extending into the containing cavity 2021. Among them, the connecting shaft 403 is connected at a non-central position of the eccentric wheel 404, that is, the eccentric wheel 404 is designed to have a gravity center offset, so as to generate centrifugal force when rotating. Preferably, the motor 401 is a stepper motor 401 or a direct current servo motor 401, so as to control the rotation speed and torque; the second bearing 402 can be a rolling bearing or an oil-containing bearing, so as to support the rotational movement of the connecting shaft 403. Further, the connecting shaft 403 is coupled with the motor 401 through a key groove or a shaft coupling, so as to ensure efficient power transmission. When the motor 401 is started, the connecting shaft 403 drives the eccentric wheel 404 to rotate in the containing cavity 2021. Due to the eccentric effect, the eccentric wheel 404 periodically contacts the inner wall of the containing cavity 2021 and applies a tangential force, thereby pushing the knife-edge plate assembly 2 to swing. In this way, this built-in driving method directly applies the excitation force to the vicinity of the swing center, avoiding the attenuation problem of traditional external driving force, and significantly improving the uniformity of sand particle distribution.

[0022] It should be understood that the foregoing detailed description of the application, rather than limiting the application, is intended to explain and describe the current implementation of the application. Therefore, any modification, equivalent replacement or improvement made without departing from the spirit and scope of the application should be included in the protection scope of the application. In addition, the appended claims of the application are intended to cover all changes and modifications falling within the scope and boundary of the appended claims, or the equivalent form of such scope and boundary.

Claims

1. A sand-laying device, characterized in that, include: Two symmetrically arranged mounting seats (1), a blade plate assembly (2) disposed between the two mounting seats (1), the blade plate assembly (2) having a receiving cavity (2021) at least one end, two central shaft assemblies (3) respectively disposed on the two mounting seats (1) and rotatably connected to the two ends of the blade plate assembly (2), and an eccentric assembly (4) disposed on at least one mounting seat (1) and extending into the corresponding end of the receiving cavity (2021), the eccentric assembly (4) forming a movable space with the receiving cavity (2021) and being able to be tangent to the inner wall of the receiving cavity (2021) when rotating, so as to drive the blade plate assembly (2) to swing around the central shaft assembly (3).

2. The sand-laying device according to claim 1, characterized in that, The blade plate assembly (2) includes: a long strip-shaped support beam (203), a blade plate (201) disposed on the support beam (203), and two guide seats (202) respectively disposed at both ends of the support beam (203), wherein the guide seats (202) have the receiving cavity (2021).

3. The sand-laying device according to claim 1, characterized in that, The central shaft assembly (3) includes: a central shaft (301) with one end fixed on the two mounting seats (1) and a first bearing (302) disposed at the other end of the central shaft (301), the first bearing (302) being rotatably connected to the end of the blade plate assembly (2).

4. The sand-laying device according to claim 1, characterized in that, The eccentric assembly (4) includes: a motor (401) fixed on the mounting base (1), a second bearing (402) disposed on the mounting base (1) corresponding to the position of the motor (401), a connecting shaft (403) with one end passing through the second bearing (402) and connected to the motor (401), and an eccentric wheel (404) connected to the other end of the connecting shaft (403) and extending into the receiving cavity (2021), wherein the connecting shaft (403) is connected to the non-central position of the eccentric wheel (404).

5. The sand-laying device according to claim 2, characterized in that, The blade plate (201) includes: multiple interconnected blade plate segments (2011).

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