A 3D printing powder spreading device for cemented carbide powder

Abstract

The application discloses a 3D printing powder spreading device for hard alloy powder, relates to the technical field of hard alloy powder spreading, and aims to solve the technical problem that the existing powder spreading roller lacks effective design for inhibiting "ploughing and cutting scratches" and "air blockage stopping effect". The four structures of bidirectional variable-pitch spiral groove, constrained micro-vibration, air pressure anti-static and vibration extrusion forced deformation are gradually coupled to form a complete hard alloy special powder spreading system: the spiral groove realizes basic air breaking and smoothing, the micro-vibration realizes global anti-ploughing and cutting, the air pressure realizes anti-static and secondary air breaking, and the vibration extrusion realizes forced driving and long-term stability, so that a series of defects such as ploughing and cutting scratches, air blockage stopping, static aggregation, roller surface sticky mass, powder surface convexity and fault, etc. in the hard alloy powder spreading process are solved, the powder bed density, uniformity and forming stability are significantly improved, and the use requirements of high-end equipment on high-precision, high-reliability and long service life of hard alloy components are met.

Description

Technical Field

[0001] This invention relates to the field of cemented carbide powder spreading technology, and more specifically, to a 3D printing powder spreading device for cemented carbide powder. Background Technology

[0002] Hard alloys, with their superior properties such as high hardness, high wear resistance, and high temperature resistance, are widely used in high-end manufacturing fields such as machining, aerospace, and mold making. 3D printing technology (additive manufacturing) provides a new path for the integrated molding of complex hard alloy components. Among them, the powder spreading roller in the powder spreading device is the core component of the 3D printing equipment, responsible for uniformly spreading hard alloy powder to form a dense powder bed. The quality of powder spreading directly determines the density, mechanical properties, and molding accuracy of the printed parts, and is a key link to ensure the industrial application of hard alloy 3D printing technology.

[0003] However, existing powder spreading rollers, when adapted for cemented carbide powder processing, still have significant drawbacks due to limitations in powder characteristics and structural design: Firstly, cemented carbide powder has extremely high hardness (Vickers hardness HV1500+), with irregular particle shapes and some having sharp edges or protruding tips. During the powder spreading process, when the powder spreading roller moves relative to the cured powder layer, these high-hardness particles act like "miniature knife tips," mechanically plowing and scratching the cured surface, damaging the integrity of the interlayer bonding surface—the microgrooves formed on the cured surface reduce the adhesion between subsequent powder and the cured layer. In addition to reduced contact area, mechanical damage can also weaken the interlayer metallurgical bonding effect, leading to a decrease in interlayer bonding strength. This makes printed parts prone to delamination and detachment, affecting structural integrity and service life. Secondly, cemented carbide powder is mostly micron-sized, with tight packing and tiny gaps between particles. When the powder spreading roller spreads powder at high speed, the rapid accumulation of powder layers prevents air from escaping in time, forming numerous micro-air pockets. These micro-air pockets cannot rupture and push against local powder beds, causing looseness and protrusions, resulting in a sharp drop in powder bed density. Moreover, this defect is microscopically invisible and difficult to detect. During subsequent laser melting / sintering, the micro-air pocket areas cannot be fully fused, eventually transforming into internal micropores and unfused defects, significantly reducing the mechanical properties, wear resistance, and corrosion resistance of the components, failing to meet the high precision and high reliability requirements of high-end equipment for cemented carbide components.

[0004] Existing powder spreading devices are mostly designed based on optimizations of conventional metal powders (such as titanium alloys and stainless steel powders), without specifically adapting to the high hardness and fine particle size characteristics of cemented carbide powders. Therefore, we propose a 3D printing powder spreading device for cemented carbide powders. Summary of the Invention

[0005] The purpose of this invention is to provide a 3D printing powder spreading device for cemented carbide powder, so as to solve the technical problem that existing powder spreading rollers lack effective design to suppress "ploughing scratches" and "air resistance effect".

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a 3D printing powder spreading device for cemented carbide powder, comprising a powder spreading roller body, wherein fixed sides are provided at both ends of the powder spreading roller body, the powder spreading roller body is rotatably connected to the fixed sides, and a powder spreading drive unit is installed on one of the fixed sides. Multiple sets of bidirectional variable pitch spiral grooves are formed on the outer periphery of the powder spreading roller body, wherein the bidirectional variable pitch spiral grooves are composed of left-handed left-handed grooves and right-handed right-handed grooves, and the left-handed grooves and right-handed grooves intersect in the middle; The powder spreading roller has a hollow cavity, and a micro-vibration structure is provided on the inner wall of the powder spreading roller. The micro-vibration structure includes an annular damping ring. The damping ring is made of a highly damped elastic material. The damping ring is fixed to the inner wall of the powder spreading roller. A vibrating element is provided on the inner circumference of the damping ring, and a vibration drive unit is connected to one side of the vibrating element.

[0007] Preferably, the pitch of the bidirectional variable pitch spiral groove gradually decreases from the middle to both ends, forming a geometric shape that extrudes and guides the flow to both sides, and the groove size of the left-hand and right-hand spiral grooves gradually decreases from the center of the powder spreading roller to the outside of the powder spreading roller.

[0008] Preferably, the vibrating element includes a central shaft connected to the vibration drive unit, the central shaft being located in the lower half of the powder spreading roller body, a bushing being connected to the outer periphery of the central shaft, and a protruding block extending from the outer periphery of the bushing.

[0009] Preferably, the inner ring of the damping ring is fixed with a plurality of inner convex strips arranged in a ring array, and when the convex block rotates to a position perpendicular to the powder-spreading plane, it contacts the inner convex strips to form a vibration source.

[0010] Preferably, the bottom walls of both the left-hand and right-hand spiral grooves are fixed with compressed air antistatic structures. The compressed air antistatic structures are generally closed-frame shapes with a spiral twisted shape, and the compressed air antistatic structures are generally made of elastic materials.

[0011] Preferably, the compressed air antistatic structure has inclined elastic frames on both sides, and the two elastic frames tilt outward to form a large-diameter opening. During the powder spreading and swishing process, the compressed air antistatic structure generates elastic deformation by compressing the hard alloy powder.

[0012] Preferably, the elastic frame is further provided with multiple concave arcs, and a vibration extrusion structure is provided on one side of each concave arc.

[0013] Preferably, the inner convex strips and the vibratory extrusion structure are staggered in a spiral shape, and the damping ring sidewall has multiple through holes corresponding to the positions of the vibratory extrusion structure.

[0014] Preferably, the vibratory extrusion structure includes an elastic pressure ball, the outer periphery of which is fixed to a damping ring, and the pressure ball is connected to a push rod, which passes through the opening and contacts the concave arc side on its outer periphery.

[0015] Preferably, the fixed side is connected to the external powder spreading mechanism, and both the vibration drive and the powder spreading drive are motors.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention, by setting a bidirectional variable-pitch spiral groove on the outer periphery of the powder spreading roller, adopts a dual gradual structure with the pitch decreasing from the middle to both ends and the groove size decreasing from the center to the outside. Under the combined motion of the powder spreading roller's rotation and horizontal translation, it can preferentially contact the powder bed at the middle intersection position, guiding the air inside the powder bed to be directionally discharged to both ends of the roller along the spiral trajectory, initially breaking up micro-air clumps; at the same time, the decreasing groove size gradually compresses the powder in the groove, further crushing the remaining closed air clumps, improving the density of the powder bed. The powder moves directionally to both ends along the spiral trajectory, which can continuously push and smooth hard alloy particles with sharp edges or protruding tips, reducing the risk of plowing and scratching the solidified layer by the particle tips. From the geometric structure level, it initially realizes the dual basic functions of breaking air and suppressing plowing and scratching, laying a structural foundation for subsequent improvement of powder spreading quality.

[0017] 2. Based on the initial smoothing of the bidirectional variable pitch spiral groove, this invention utilizes a micro-vibration structure within the inner cavity of the powder spreading roller. This structure, formed by the periodic light contact and collision of the convex blocks and inner convex strips, creates a high-frequency micro-amplitude vibration source. After filtering and isolation by a damping ring, only the vertically downward micro-vibration energy is transmitted to the powder bed. The roller as a whole remains macroscopically stationary without jumping or undulating. The micro-vibration causes the hard alloy particles to loosen, sink, and collapse slightly, allowing the sharp tips of the particles to detach from the rigid contact with the cured layer. This expands the anti-plowing protection range from the spiral groove area to the entire contact surface of the powder spreading roller, achieving comprehensive protection without dead angles. This significantly improves the protection effect on the cured layer, solves the problem of limited spiral groove protection range, and further enhances the integrity of interlayer bonding.

[0018] 3. This invention addresses the problems of powder accumulation, frictional static electricity leading to powder shortages, clumping, and protrusions / delamination in spiral grooves. An elastic, closed-frame-shaped compressed antistatic structure is installed on the bottom wall of the spiral groove. The elastic frame periodically contracts, compresses, and expands as the powder rotates, creating alternating compression and relaxation zones within the groove. This reciprocating kneading of the powder further breaks down residual micro-air clusters, improving the density and uniformity of the powder bed. The alternating spatial changes cause the powder to continuously and dynamically reposition, repeatedly contacting and altering the friction direction. Particles cannot maintain a fixed posture or contact surface, and the instantaneous static charge generated by friction cannot accumulate on the surface of individual particles, making it difficult to form a stable electrostatic field and directional adsorption force. This mechanistically inhibits static electricity accumulation, preventing ultrafine powder from agglomerating and clumping towards the roller wall, and initially solving the problems of powder shortages, protrusions, and delamination on the powder-spreading surface.

[0019] 4. To avoid the problems of small fluctuation amplitude and elastic fatigue failure caused by the elastic frame relying on its own deformation, this invention uses a spirally interlaced arrangement of inner convex strips and vibratory extrusion structure to synchronously transmit the vibration and extrusion force generated by the micro-vibration structure to the pressure ball, driving the top rod to extend and retract in a directional manner and push the concave arc of the elastic frame at a fixed point, so that the elastic frame can achieve forced active deformation, no longer relying on powder extrusion and its own rebound. The forced deformation greatly improves the compression and reset amplitude of the elastic frame, forming a stronger reciprocating kneading and disturbance on the powder in the groove, further enhancing the micro-air mass breaking effect; at the same time, high-frequency vibration and forced extrusion force cause the powder to be continuously forced to turn over and its posture to switch rapidly, significantly enhancing the electrostatic dissipation effect, fundamentally reducing the risk of elastic failure, ensuring the long-term stable operation of the device, and ensuring that the effects of breaking air, preventing static electricity, and suppressing agglomerates remain consistent.

[0020] 5. This invention forms a complete cemented carbide-specific powder spreading system through four progressively advancing and synergistically coupled structural elements: bidirectional variable-pitch spiral grooves, constrained micro-vibration, compressed air anti-static, and vibratory extrusion forced deformation. The spiral grooves achieve basic air breaking and smoothing, the micro-vibration achieves full-area anti-plowing, the elastic compressed air achieves basic anti-static and secondary air breaking, and the vibratory extrusion structure achieves forced driving and long-term stability. This system suppresses a series of unique defects in the cemented carbide powder spreading process, such as plowing and scratching by high-hardness particles, micro-scale air blockage, electrostatic agglomeration of ultrafine powder, roller surface sticking, and powder surface protrusions and fractures. It significantly improves the density, uniformity, and forming stability of the powder bed, ensuring that the printed components are free of internal micropores, delamination, and incomplete fusion defects, meeting the high-precision, high-reliability, and long-life requirements of high-end equipment for cemented carbide components. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the present invention.

[0022] Figure 2 This is a schematic diagram of the internal structure of one end of the powder spreading roller in this invention.

[0023] Figure 3 For the present invention Figure 2 An enlarged schematic diagram of the structure at point A in the middle.

[0024] Figure 4 This is a schematic diagram of the bidirectional variable pitch spiral groove in this invention.

[0025] Figure 5 This is a schematic diagram of the connection structure between the damping ring and the powder spreading roller in this invention.

[0026] Figure 6 This is a schematic diagram of the distribution structure of the inner convex strip and the vibration extrusion structure inside the damping ring in this invention.

[0027] Figure 7 This is a schematic diagram of the structure of the vibrating element in this invention.

[0028] Figure 8 This is a schematic diagram of the combined structure of the compressed air antistatic structure and the vibratory extrusion structure in this invention.

[0029] Figure 9 This is a schematic diagram of a single compressed air antistatic structure in this invention.

[0030] Figure 10 This is a schematic diagram of a single vibratory extrusion structure in this invention.

[0031] Figure 11 This is a half-section schematic diagram of a single vibratory extrusion structure in this invention.

[0032] Explanation of the labels in the diagram: 1. Powder spreading roller body; 2. Fixed side; 3. Powder spreading drive unit; 4. Bidirectional variable pitch spiral groove; 401. Left-hand spiral groove; 402. Right-hand spiral groove; 5. Micro-vibration structure; 501. Damping ring; 52. Vibrating component; 521. Central shaft; 522. Bushing; 523. Convex block; 524. Inner convex strip; 6. Vibration drive unit; 7. Compressed air anti-static structure; 701. Elastic frame; 702. Inner concave arc; 8. Vibration extrusion structure; 801. Pressure ball; 802. Top rod. Detailed Implementation

[0033] like Figures 1 to 11As shown, the present invention relates to a 3D printing powder spreading device for cemented carbide powder, comprising a powder spreading roller 1, with fixed sides 2 at both ends of the powder spreading roller 1, the fixed sides 2 being connected to an external powder spreading mechanism, the external powder spreading mechanism being provided with a driving part for horizontal translation, which is prior art and will not be described in detail here. The powder spreading roller 1 is rotatably connected to the fixed sides 2, one of the fixed sides 2 being equipped with a powder spreading driving part 3. Multiple sets of bidirectional variable pitch spiral grooves 4 are formed on the outer periphery of the powder spreading roller 1, the bidirectional variable pitch spiral grooves 4 being composed of a left-handed left-handed groove 401 and a right-handed right-handed groove 402, the left-handed groove 401 and the right-handed groove 402 intersecting in the middle, the pitch of the bidirectional variable pitch spiral grooves 4 gradually decreasing from the middle to both ends, forming a geometric shape of extrusion and guidance to both sides, the groove opening size of the left-handed groove 401 and the right-handed groove 402 gradually decreasing from the center of the powder spreading roller 1 to the outside of the powder spreading roller 1.

[0034] Working principle: The powder spreading roller 1 rotates under the drive of the powder spreading drive unit 3 and moves horizontally along the powder spreading plane with the external powder spreading mechanism; the bidirectional variable pitch spiral groove 4 on the outer periphery of the powder spreading roller 1 moves synchronously with the roller. The middle intersection of the left spiral groove 401 and the right spiral groove 402 first contacts the powder bed surface. Under the combined action of rotation and translation, the bidirectional variable pitch spiral groove 4 creates turbulent disturbance on the powder on the surface of the powder bed. Combined with the geometric shape of the pitch gradually decreasing from the middle to both ends, the air inside the powder bed is continuously guided and discharged to both ends of the roller along the spiral trajectory, initially breaking up the micro air clumps; the groove size of the left spiral groove 401 and the right spiral groove 402 gradually decreases from the center of the roller to the outside, so that the powder entering the groove is gradually compressed during the movement, further squeezing and breaking up the residual micro air clumps, and improving the density of the powder bed; at the same time, the powder moves directionally to both ends of the roller along the spiral trajectory, forming a continuous pushing and smoothing effect on the hard alloy particles with sharp edges or protruding tips, reducing the risk of plowing and scratching the solidified layer by the particle tips.

[0035] As described above, the bidirectional variable pitch spiral groove 4 adopts a dual gradual structure with the pitch decreasing from the middle to both ends and the groove size decreasing from the center to the outside. Under the combined motion of the rotation and horizontal translation of the powder spreading roller 1, it achieves a triple synergistic effect: First, the middle inlet end prioritizes contact with the powder bed, guiding the air in the powder bed to both ends of the roller along the spiral trajectory, quickly breaking up the surface micro-air masses; second, the decreasing groove size gradually compresses the powder in the groove, further crushing the remaining closed air masses and improving the density of the powder bed; third, through the directional movement of the powder along the spiral to both ends, it continuously pushes and smooths the sharp particles of cemented carbide, reducing the risk of plowing and scratching the solidified layer by the particle tips, and initially realizing the dual functions of breaking air and suppressing plowing and scratching from the geometric structure level.

[0036] Furthermore, the above-mentioned effect of reducing the risk of plowing and scratching of the cured layer by the tip of the particles when the powder is along the spiral trajectory is only effective in the part of the bidirectional variable pitch spiral groove 4. In order to further improve the protective effect, the powder spreading roller 1 has a hollow cavity and the inner wall of the powder spreading roller 1 is provided with a micro-vibration structure 5.

[0037] The micro-vibration structure 5 includes an annular damping ring 501, which is made of a highly damped elastic material. The damping ring 501 is fixed to the inner wall of the powder spreading roller 1. A vibrating element 52 is arranged on the inner circumference of the damping ring 501. A vibration drive unit 6 is connected to one side of the vibrating element 52. The vibration drive unit 6 and the powder spreading drive unit 3 can be any driving device, such as a motor, which is commonly used. The vibrating element 52 includes a central shaft 521 connected to the vibration drive unit 6. The central shaft 521 is located in the lower half of the powder spreading roller 1. The outer circumference of the central shaft 521 is connected to... The bushing 522 has a protruding block 523 extending from its outer periphery. The inner ring of the damping ring 501 has a plurality of inner protruding strips 524 arranged in a ring array. When the protruding block 523 rotates to a position perpendicular to the powder-spreading plane, it contacts the inner protruding strips 524 to form a vibration source. Preferably, the gap between the protruding block 523 and the inner protruding strips 524 is 0.1-0.5mm, the contact force is in the range of 0.1-1N, the generated vibration frequency is 100-500Hz, and the vibration amplitude is 10-50μm, so that the vibration energy is transmitted only in the vertical direction.

[0038] To ensure stable vibration, the vibration drive unit 6 is a servo motor with a built-in encoder, and the powder spreading drive unit 3 is a stepper motor or servo motor. The two are synchronously controlled by a PLC controller. The controller adjusts the speed of the vibration drive unit 6 in real time according to the rotation position signal of the powder spreading drive unit 3, ensuring that the convex block 523 contacts the inner convex strip 524 when it rotates to a position perpendicular to the powder spreading plane, thus forming a stable vibration output. The speed of the vibration drive unit 6 is 3-5 times that of the powder spreading drive unit 3.

[0039] Working principle: The powder spreading roller 1 rotates with the powder spreading drive unit 3. The damping ring 501 fixed on the inner wall of its cavity rotates synchronously with the powder spreading roller 1. The multiple inner protrusions 524 of the inner ring of the damping ring 501 also make circular motion together. The vibration drive unit 6 drives the central shaft 521 to rotate at high speed. The rotation speed of the central shaft 521 needs to be greater than that of the powder spreading roller 1. The central shaft 521 drives the bushing 522 and the convex block 523 to rotate continuously. When the convex block 523 rotates to a position perpendicular to the powder spreading plane, it will periodically touch and collide with the inner protrusions 524 to form a stable high-frequency micro-amplitude vibration source.

[0040] The vibration is filtered and isolated by the damping ring 501 made of high-damping elastic material, and only the vertically downward micro-vibration energy is transmitted to the surface of the powder spreading roller 1. The powder spreading roller 1 as a whole remains macroscopically still, without radial jump or wavy undulation. The micro-vibration energy acts on the hard alloy particles on the powder bed surface, causing the particles to loosen slightly, sink slightly, and fall slightly. This allows the sharp edges or protruding tips of the particles to detach from the rigid contact with the cured layer. Thus, on the basis of smoothing by the bidirectional variable pitch spiral groove 4, the risk of hard alloy particles ploughing and scratching the cured layer is further eliminated, and the protection effect is greatly improved.

[0041] Furthermore, due to the design of the bidirectional variable pitch spiral groove 4, which has a certain depth, during the spinning and leveling process, the hard alloy powder may be accumulated in the groove. During friction, static charge is easily generated, which may lead to local powder shortage on the powder spreading surface, fine powder clumps adhering to the powder spreading roller 1 → the next layer suddenly falling off → powder surface protrusion and discontinuity.

[0042] Both the left-hand spiral groove 401 and the right-hand spiral groove 402 have a compressed air antistatic structure 7 fixed to their inner bottom walls. The compressed air antistatic structure 7 is a closed frame shape with a spiral twist. Its material can be polyurethane elastomer with a hardness of Shore A 80-90 and an elastic modulus of 10-30MPa. Its overall length is consistent with the length of the bidirectional variable pitch spiral groove. The two sides of the compressed air antistatic structure 7 are elastic frames 701 with an inclination. The two elastic frames 701 are inclined outward to form a large-diameter opening. The thickness of the elastic frame 701 is 0.3-0.8mm, the inclination angle is 15-30 degrees, and the opening width is 2-4mm larger than the bottom width of the groove. During the powder spreading and spiral pushing process, the compressed air antistatic structure 7 is subjected to the extrusion of hard alloy powder and undergoes elastic deformation. The deformation range is 10%-20% of the opening width (polyurethane elastomer is used as an example here).

[0043] Working principle: During the spreading and leveling process of the powder spreading roller 1, the hard alloy powder in the bidirectional variable pitch spiral groove 4 is continuously rolled into the groove. The compressed air antistatic structure 7 at the bottom of the groove moves synchronously with the roller. When it moves to the position of contact and compression with the powder spreading plane, the powder exerts a compressive force on the elastic frames 701 with slopes on both sides, causing the elastic frames 701 to elastically shrink and deform, and the space inside the groove is compressed. When it moves to the position of disengaging from the compression, the elastic frames 701 quickly recover and expand due to their own elasticity, and the space inside the groove returns to its original state. Different groove spaces have the same volume. Through the undulating deformation of the elastic frames 701, a relaxation and pressing effect is generated. The elastic frames 701 continue to rotate with the roller, periodically shrinking, compressing and expanding, so that a continuous squeezing zone and relaxation zone are formed in the groove, which reciprocates and kneads the powder in the groove, further breaking up the residual micro-air clumps in the powder and improving the density. At the same time, in conjunction with the above-mentioned high-frequency micro-vibration, the reciprocating kneading can be strengthened, and even if there is a small amount of powder, it can be shaken off.

[0044] The reciprocating deformation of the elastic frame 701 causes alternating spatial changes, keeping the powder in the groove in a state of dynamic repositioning, repeated contact, and continuous change of friction direction. The particles cannot maintain a fixed posture and a fixed contact surface. The instantaneous static charge generated by friction cannot remain and accumulate on the surface of a single particle because the particles are constantly turning over, exchanging with neighboring particles, and the contact objects are constantly changing. A stable layer of the same polarity charge and a unified electrostatic field cannot be formed. At the same time, the periodic squeezing and relaxation will disrupt the migration path of the ultrafine powder, preventing it from being directionally adsorbed, agglomerated, and clumped to the roller wall under the electrostatic pull. This further inhibits the accumulation of static electricity, powder sticking to the roller surface, powder shortage on the powder spreading surface, powder protrusion, and discontinuity defects.

[0045] Furthermore, the above-mentioned effect is achieved through the self-compression deformation of the elastic frame 701. However, there may be cases where the effect fails due to small fluctuations or elastic fatigue. To address this, the elastic frame 701 is also provided with multiple concave arcs 702. A vibration extrusion structure 8 is provided on one side of the concave arc 702. The inner convex strips 524 and the vibration extrusion structure 8 are distributed in a spiral pattern. The side wall of the damping ring 501 has multiple through-holes corresponding to the positions of the vibration extrusion structure 8. The vibration extrusion structure 8 includes an elastic compression ball 801. The outer part of the compression ball 801 is fixed to the damping ring 501. 1. A push rod 802 is connected, which passes through the through-hole and contacts one side of the concave arc 702 on its outer periphery. In one embodiment, the diameter of the through-hole is 0.8-1.2mm, the diameter of the push rod 802 is 0.7-1.0mm, the gap between the push rod 802 and the through-hole is 0.1-0.2mm, the stroke of the push rod 802 is 0.5-1.5mm, and a sealing ring is provided between the through-hole and the push rod 802 to prevent powder from entering the damping ring 501. The contact point between the end of the push rod 802 and the concave arc 702 can be hemispherical to reduce friction, with a radius of 0.3-0.5mm.

[0046] Working principle: When the convex block 523 of the vibrating element 52 rotates and contacts the inner convex strip 524 of the damping ring 501 to generate vibration, the inner convex strip 524 transmits the vibration and extrusion force synchronously to the vibrating extrusion structure 8 on the side wall of the damping ring 501. The pressure ball 801 is subjected to periodic extrusion and vibration, which drives the push rod 802 to make directional telescopic movement along the through hole of the damping ring 501. The end of the push rod 802 continuously pushes the concave arc 702 on the elastic frame 701, causing the elastic frame 701 to generate forced active deformation, no longer relying on powder extrusion and its own rebound, thereby avoiding functional failure caused by too small fluctuation amplitude or elastic fatigue.

[0047] Under forced deformation, the compression and reset amplitude of the elastic frame 701 is significantly improved, forming a stronger reciprocating kneading and disturbance on the hard alloy powder in the bidirectional variable pitch spiral groove 4, further breaking up the micro air clumps inside the powder bed and improving the compaction uniformity; at the same time, the high-frequency vibration and forced extrusion force brought by the top rod 802 act synchronously on the powder in the groove, so that the particles are continuously in a dynamic state of forced tumbling and rapid posture switching. The static charge generated by the friction between particles cannot remain and accumulate on the surface, making it difficult to form a stable electrostatic field and directional adsorption force. The ultrafine powder will not agglomerate and stick to the roller wall, thereby strengthening the suppression of defects such as powder shortage, powder protrusion and discontinuity on the powder spreading surface, and greatly improving the long-term operating stability of the device.

[0048] The above-mentioned triple reinforcement effect is achieved by using internal micro-vibration forced drive and external elastic frame 701 active deformation to reduce the problems of weak rebound, small fluctuation and elastic fatigue failure of elastic frame 701 itself.

[0049] Forced deformation expansion, with the top rod 802 pressing the concave arc 702 at a fixed point, allows the elastic frame 701 to deform more significantly and move more powerfully, unaffected by elastic fatigue; vibration-kneading coupling synchronously transmits internal micro-vibrations to the powder in the tank, enhancing the ability to break up air, disperse clumps, and prevent particles from collapsing; electrostatic dissipation is doubled, with the powder being forcibly disturbed and frequently repositioned, making it more difficult for charges to accumulate, thus suppressing problems such as powder sticking, powder shortage, and delamination.

[0050] After the powder is spread, the roller of this application can be run idle for a period of time to discharge the residual powder in the tank and avoid affecting the next use.

[0051] The embodiments disclosed in this invention are preferred embodiments, but are not limited thereto. Those skilled in the art can easily understand the spirit of this invention based on the above embodiments and make different extensions and variations, but as long as they do not depart from the spirit of this invention, they are all within the protection scope of this invention.

Claims

1. A 3D printing powder spreading device for cemented carbide powder, comprising a powder spreading roller (1), wherein fixed sides (2) are provided at both ends of the powder spreading roller (1), the powder spreading roller (1) is rotatably connected to the fixed sides (2), and a powder spreading drive unit (3) is installed on one of the fixed sides (2), characterized in that, The powder spreading roller (1) has multiple sets of bidirectional variable pitch spiral grooves (4) on its outer periphery. The bidirectional variable pitch spiral grooves (4) are composed of a left-handed spiral groove (401) and a right-handed spiral groove (402), and the left-handed spiral groove (401) and the right-handed spiral groove (402) intersect in the middle. The powder spreading roller (1) has a hollow cavity. The inner wall of the powder spreading roller (1) is provided with a micro-vibration structure (5). The micro-vibration structure (5) includes an annular damping ring (501). The damping ring (501) is made of an elastic material with high damping. The damping ring (501) is fixed to the inner wall of the powder spreading roller (1). A vibrating element (52) is provided on the inner circumference of the damping ring (501). A vibration drive unit (6) is connected to one side of the vibrating element (52).

2. The 3D printing powder spreading device for cemented carbide powder according to claim 1, characterized in that, The pitch of the bidirectional variable pitch spiral groove (4) gradually decreases from the middle to both ends, forming a geometric shape that squeezes and guides the flow to both sides. The groove size of the left spiral groove (401) and the right spiral groove (402) gradually decreases from the center of the powder spreading roller (1) to the outside of the powder spreading roller (1).

3. The 3D printing powder spreading device for cemented carbide powder according to claim 2, characterized in that, The vibrating element (52) includes a central shaft (521) connected to the vibration drive unit (6). The central shaft (521) is located in the lower half of the powder spreading roller body (1). A bushing (522) is connected to the outer periphery of the central shaft (521), and a protruding block (523) extends from the outer periphery of the bushing (522).

4. The 3D printing powder spreading device for cemented carbide powder according to claim 3, characterized in that, The inner ring of the damping ring (501) is fixed with a plurality of inner protruding strips (524) arranged in a ring array. When the convex block (523) rotates to a position perpendicular to the powder-spreading plane, it contacts the inner protruding strips (524) to form a vibration source.

5. A 3D printing powder spreading device for cemented carbide powder according to claim 4, characterized in that, The bottom walls of the left-hand groove (401) and the right-hand groove (402) are both fixed with compressed air antistatic structures (7). The compressed air antistatic structure (7) is a closed frame with a spiral twist shape and is made of an elastic material.

6. A 3D printing powder spreading device for cemented carbide powder according to claim 5, characterized in that, The compressed air antistatic structure (7) has inclined elastic frames (701) on both sides. The two elastic frames (701) are inclined outward to form a large diameter opening. The compressed air antistatic structure (7) generates elastic deformation by squeezing hard alloy powder during the powder spreading and spinning process.

7. A 3D printing powder spreading device for cemented carbide powder according to claim 6, characterized in that, The elastic frame (701) is also provided with a plurality of concave arcs (702), and a vibration extrusion structure (8) is provided on one side of the concave arcs (702).

8. A 3D printing powder spreading device for cemented carbide powder according to claim 7, characterized in that, The inner convex strip (524) and the vibratory extrusion structure (8) are arranged in a spiral pattern and are staggered. The side wall of the damping ring (501) has multiple through holes corresponding to the positions of the vibratory extrusion structure (8).

9. A 3D printing powder spreading device for cemented carbide powder according to claim 8, characterized in that, The vibratory extrusion structure (8) includes an elastic pressure ball (801), the outer periphery of which is fixed to a damping ring (501), and the pressure ball (801) is connected to a push rod (802), which passes through the opening and contacts one side of the concave arc (702) on its outer periphery.

10. A 3D printing powder spreading device for cemented carbide powder according to any one of claims 1-9, characterized in that, The fixed side (2) is connected to the external powder spreading mechanism, and both the vibration drive unit (6) and the powder spreading drive unit (3) are motors.

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