Mechanism for accurately controlling feeding of tungsten carbide powder

Abstract

The invention relates to a mechanism for accurately controlling feeding of tungsten carbide powder. The mechanism comprises a feeding hopper and a discharging hopper. The upper ends of the rapid discharging pipeline and the material supplementing pipeline are communicated with the discharging opening of the feeding hopper, and the lower ends of the rapid discharging pipeline and the material supplementing pipeline are communicated with the feeding opening of the discharging hopper; the rapid discharging large spiral shaft is mounted in the rapid discharging pipeline; the material supplementing small spiral shaft is mounted in the material supplementing pipeline; and the diameter of the feeding end of the small feeding screw shaft is larger than that of the discharging end of the small feeding screw shaft. The feeding precision and efficiency are improved, a large and small double-spiral-shaft cooperative working mode is adopted, rapid feeding is achieved through the large spiral shaft in the early stage, precise material supplementing is achieved through the small spiral shaft in the later stage, a differential control mode is matched, efficient feeding of 50 kg / min is achieved, the feeding precision of + / -10 g is guaranteed, and the feeding efficiency is improved. The core pain point that an existing single-screw-shaft mechanism is fast and not precise, and precise and not fast is solved.

Description

Technical Field

[0001] This invention relates to the technical field of tungsten carbide powder processing, and in particular to a mechanism for precise control of tungsten carbide powder feeding. Background Technology

[0002] Nanoscale tungsten carbide powder has unique physical properties. Its particle size reaches the nanoscale level. It also has characteristics such as large differences in looseness, high specific surface area, high density, easy agglomeration, and strong van der Waals attraction between molecules. These characteristics make it easy for it to adhere, agglomerate, and have uneven feeding during the feeding process.

[0003] Currently, most existing feeding mechanisms on the market adopt a single spiral shaft structure. When conveying nano-sized tungsten carbide powder, this structure is prone to collapsing material drop, making it impossible to achieve stable and uniform material conveying. At the same time, the control method of the single spiral shaft is limited and difficult to adapt to the physical characteristics of nano-sized tungsten carbide powder, resulting in either low efficiency or insufficient precision during the feeding process, failing to meet the dual requirements of "high efficiency + precision" in industrial production.

[0004] Furthermore, the existing single-spiral shaft feeding mechanism has not been structurally optimized to address the adhesion and agglomeration characteristics of nano-sized tungsten carbide powder, which easily leads to material sticking to the inner wall of the equipment and accumulating voids, further affecting the feeding stability and accuracy. At the same time, the wear of the material-equipment contact surface is relatively fast, and the strong adhesion of nano-powder due to van der Waals forces will exacerbate equipment wear and material waste, increasing production costs.

[0005] A search revealed Chinese patent publication number CN202625047U, which discloses a "double-helix feeding device." This device employs an inverted trapezoidal hopper, a collection bin, and vertically arranged feeding helices of varying sizes, aiming to solve the problem of bridging and arching of viscous materials on the inclined surface of a conical receiving hopper. This solution improves the smoothness of discharge for materials with poor flowability by replacing the receiving hopper with a hollow cylindrical shape, thus eliminating the inclined surface.

[0006] However, after in-depth analysis, this existing technology (CN202625047U) still has significant shortcomings when dealing with the specific material of nano-sized tungsten carbide powder: The problem is singular: its invention focuses on solving the arching and bridging at the discharge port (feeding hopper), which is a passive improvement of the "result". However, it does not address the common adhesion problem of nanoscale powders caused by strong van der Waals forces throughout the entire conveying path (including the feed hopper and the inner wall of the feeding pipe), as well as the resulting material residue, weight error and collapse.

[0007] The structure lacks specificity: its large and small spirals are simply arranged vertically to reduce the width of the equipment. The spirals themselves (such as diameter and lead) are not optimized for the nonlinear flow characteristics of nanoparticles, which involve "agglomeration followed by collapse." In particular, the small spirals, with their constant structure, cannot achieve precise and adaptive flow rate adjustment at the end of the feeding phase.

[0008] Lack of dynamic intervention and protection: This solution relies entirely on mechanical structures and lacks auxiliary devices to actively and dynamically intervene in the material state during the conveying process (such as breaking newly formed hollow arches and shaking off slightly adhered layers), thus failing to prevent problems from occurring.

[0009] Long-term wear resistance of the equipment was not considered: no wear-resistant solutions were mentioned for the high hardness of tungsten carbide powder. After long-term operation, the wear of the spiral and the pipe will directly change the feeding volume ratio, resulting in accuracy drift.

[0010] Therefore, existing technologies have failed to systematically solve the core contradiction of "adhesion, agglomeration, and wear" in the efficient and high-precision feeding of nano-sized tungsten carbide powder.

[0011] In view of the above-mentioned shortcomings, the designer actively researched and innovated in order to create a mechanism for precise control of tungsten carbide powder feeding, making it more valuable for industrial applications. Summary of the Invention

[0012] To address the aforementioned technical problems, the purpose of this invention is to provide a mechanism for precisely controlling the feeding of tungsten carbide powder.

[0013] To achieve the above objectives, the present invention adopts the following technical solution: A mechanism for precise control of tungsten carbide powder feeding, comprising a feed hopper and a discharge hopper; Also includes: The fast discharge pipe and the replenishment pipe are both connected at the top to the discharge port of the feed hopper and at the bottom to the feed port of the discharge hopper. A large spiral shaft for rapid feeding is installed inside the rapid feeding pipe and is driven by a servo motor. The feeding screw shaft is installed inside the feeding pipe and is driven by a servo motor. The feeding screw shaft is a variable diameter shaft, with the diameter of its inlet end being larger than the diameter of its outlet end. The control system, electrically connected to the large helical shaft drive servo motor, the small helical shaft drive servo motor, and a downstream weighing mechanism, is configured to perform the following steps: Step 1: Control the start of the servo motor driving the large spiral shaft to drive the large spiral shaft for rapid unloading; Step 2: Receive feedback from the downstream weighing mechanism. When the weight reaches the first threshold, control the large spiral shaft drive servo motor to stop and control the small spiral shaft drive servo motor to start, driving the feeding small spiral shaft to run in the first mode. Step 3: When the weight reaches the second threshold, control the small spiral shaft to drive the servo motor to drive the feeding small spiral shaft in the second mode. The single feeding amount in the second mode is less than that in the first mode. Step 4: When the weight reaches the target value, control the small spiral shaft drive servo motor to stop.

[0014] As a further improvement to the present invention, it also includes: Air disc, installed on the inner wall of the feed hopper near the discharge port; Air hammer, installed on the outer wall of the hopper; The control system is also electrically connected to the pneumatic disc and pneumatic hammer. During the execution of steps 1 to 4, the air disc and air hammer are controlled to work intermittently.

[0015] As a further improvement of the present invention, the first threshold is 85% to 95% of the target weight, and the second threshold is 95% to 99% of the target weight.

[0016] As a further improvement of the present invention, the first threshold is 90% of the target weight, and the second threshold is 98% of the target weight.

[0017] As a further improvement of the present invention, the feeding small spiral shaft includes a first diameter end and a second diameter end of the small spiral shaft connected together. The diameter of the first diameter end of the small spiral shaft is larger than the diameter of the second diameter end of the small spiral shaft, and the lead of the first blade of the small spiral shaft on the first diameter end of the small spiral shaft is smaller than the lead of the second blade of the small spiral shaft on the second diameter end of the small spiral shaft.

[0018] As a further improvement of the present invention, the diameter of the first diameter end of the small spiral shaft is 45~55mm, and the spacing of the first blades of the small spiral shaft is 35~45mm; the diameter of the second diameter end of the small spiral shaft is 30~35mm, and the spacing of the second blades of the small spiral shaft is 55~65mm.

[0019] As a further improvement of the present invention, the first mode is a constant speed mode, and the second mode is a low-speed continuous rotation mode or an intermittent jog mode.

[0020] As a further improvement of the present invention, the diameter of the large spiral shaft for rapid feeding is larger than the diameter of the first diameter end of the small spiral shaft for feeding.

[0021] As a further improvement of the present invention, the diameter of the large spiral shaft for rapid feeding is 54~60mm, and the spacing between its large spiral shaft blades is 95~105mm.

[0022] As a further improvement of the present invention, a coating is also included, wherein a DLC coating is provided on the inner wall of the feed hopper, the rapid discharge pipe, the replenishment pipe, the feed hopper, and the surface of the rapid discharge large spiral shaft and the replenishment small spiral shaft. The DLC coating is prepared by physical vapor deposition process.

[0023] By means of the above-described solution, the present invention has at least the following advantages: 1. Achieve dual improvement in feeding accuracy and efficiency: Adopting a collaborative working mode of large and small double spiral shafts, the large spiral shaft provides rapid feeding in the early stage, while the small spiral shaft provides precise feeding in the later stage. Combined with differentiated control methods, it achieves efficient feeding of 50kg / minute and ensures feeding accuracy of ±10g, solving the core pain point of existing single spiral shaft mechanisms that are "fast but not accurate, accurate but not fast".

[0024] 2. Reduce material agglomeration and adhesion, and improve feeding stability: The feeding small spiral shaft adopts a structural optimization design with variable diameter and variable lead, which can realize dynamic adjustment of feeding volume and effectively reduce the compaction and agglomeration of nano-sized tungsten carbide powder; at the same time, the surface of the double spiral shaft and the inner wall of the hopper adopt DLC coating process, which significantly reduces the adhesion of nano-powder caused by van der Waals attraction, avoids material sticking to the equipment, and ensures a smooth and stable feeding process.

[0025] 3. Reduce the incidence of material collapse and avoid material waste: Air discs are installed in the feed hopper and air hammers are installed in the discharge hopper. The air discs can effectively break up the hollow arches and corner accumulations formed during the feeding process, and the air hammers can prevent materials from sticking to the inner wall of the hopper. The double protection effectively reduces the probability of material collapse and reduces material waste, which is in line with the high value of tungsten carbide powder and reduces production losses.

[0026] 4. Extend equipment lifespan and reduce maintenance costs: DLC coating process can not only reduce material adhesion, but also significantly increase the wear resistance of parts surface, reduce friction loss between equipment and materials, extend the service life of core components such as twin helical shafts and hoppers, and reduce equipment maintenance frequency and maintenance costs.

[0027] 5. High adaptability and practicality: The overall structural design is designed to fit the core physical characteristics of nano-sized tungsten carbide powder, such as large differences in looseness and easy agglomeration. It can be quickly adapted to industrial production scenarios without the need for major modifications to existing production processes, and has strong practicality and promotional value.

[0028] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the following are preferred embodiments of the present invention described in detail with reference to the accompanying drawings. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of a mechanism for precise control feeding of tungsten carbide powder according to the present invention; Figure 2 This is a schematic diagram of the rapid feeding spiral shaft of the present invention; Figure 3 This is a schematic diagram of the feeding spiral shaft of the present invention; Figure 4 This is a schematic diagram of the operation flow of the present invention.

[0031] 1. Feed hopper; 2. Fast feeding pipe; 3. Fast feeding large spiral shaft; 4. Feeding small spiral shaft; 5. Feed hopper; 6. Air hammer; 7. Feeding pipe; 8. Air disc; 9. Small spiral shaft drive servo motor; 10. Large spiral shaft drive servo motor; 11. Large spiral shaft blade; 12. Small spiral shaft first diameter end; 13. Small spiral shaft first blade; 14. Small spiral shaft second diameter end; 15. Small spiral shaft second blade. Detailed Implementation

[0032] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0033] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0034] First embodiment of the present invention: like Figures 1-4As shown, the mechanism for precise control of tungsten carbide powder feeding in this embodiment mainly consists of the following components: feeding hopper 1, fast feeding pipe 2, fast feeding large spiral shaft 3, feeding small spiral shaft 4, feeding hopper 5, air hammer 6, feeding pipe 7, air disc 8, small spiral shaft drive servo motor 9, and large spiral shaft drive servo motor 10.

[0035] The specific connection relationships and installation positions of each component are as follows: Figure 1 As shown: The feed hopper 1 is fixedly installed on the top of the mechanism to receive nano-sized tungsten carbide powder to be fed. The discharge end of the feed hopper 1 is connected to the fast discharge pipe 2 and the replenishment pipe 7 respectively to realize the diversion and supply of materials.

[0036] The lower end of the rapid feeding pipe 2 is connected to the upper end of the feeding hopper 5. The rapid feeding large spiral shaft 3 is installed inside the rapid feeding pipe 2. One end of the spiral shaft is connected to the large spiral shaft drive servo motor 10 for transmission. The large spiral shaft drive servo motor 10 controls its rotation speed and start / stop.

[0037] The lower end of the feeding pipe 7 is connected to the upper end of the feeding hopper 5 (adjacent to the discharge end of the fast feeding pipe 2). The feeding small spiral shaft 4 is installed inside the feeding pipe 7. One end of the spiral shaft is connected to the small spiral shaft drive servo motor 9 for transmission. The small spiral shaft drive servo motor 9 controls its rotation speed, rotation mode (constant speed, variable speed, jogging) and start / stop.

[0038] The air disc 8 is fixedly installed on the upper inner wall of the feed hopper 1, near the discharge port of the feed hopper 1, and is used to break up the hollow arches and corner accumulations formed by the material during the feeding process.

[0039] The air hammer 6 is fixedly installed on the outer wall of the hopper 5, corresponding to the position on the inner wall of the hopper 5 where materials are prone to sticking. It is used to strike the wall of the hopper 5 to prevent materials from sticking.

[0040] The feeding hopper 5 is installed at the bottom of the mechanism, and its discharge end is used to connect with the feeding structure of the subsequent packaging equipment to realize the transfer of materials after precise feeding.

[0041] like Figure 2 and Figure 3 The double helical shaft shown (i.e., the large helical shaft 3 for rapid feeding and the small helical shaft 4 for replenishing material) has a diameter larger than that of the small helical shaft 4 for replenishing material.

[0042] like Figure 2The diameter of the rapid feeding spiral shaft 3 shown is the same everywhere, and several large spiral shaft blades 11 are evenly installed along the axial direction on the rapid feeding spiral shaft 3. The diameter of the rapid feeding spiral shaft 3 is 56mm, the distance between two adjacent large spiral shaft blades 11 is 100mm, and the distance between the top and bottom of the large spiral shaft blades 11 is 96mm.

[0043] like Figure 3 The feeding spiral shaft 4 shown includes a first diameter end 12 and a second diameter end 14 with different diameters at both ends. The second diameter end 14 is located on the side closer to the discharge hopper 5, and the diameter of the first diameter end 12 is larger than the diameter of the second diameter end 14. A plurality of first spiral shaft blades 13 are evenly installed axially on the first diameter end 12, and a plurality of second spiral shaft blades 15 are evenly installed axially on the second diameter end 14.

[0044] The diameter of the first diameter end 12 of the small helical shaft is 50 mm, and the diameter of the second diameter end 14 of the small helical shaft is 31.5 mm.

[0045] The distance between the first blade 13 of two adjacent small spiral shafts is 40 mm, and the distance between the second blade 153 of two adjacent small spiral shafts is 60 mm.

[0046] The distance between the top and bottom of the first blade 13 of the small helical shaft is 62mm, and the distance between the top and bottom of the second blade 15 of the small helical shaft is 62mm.

[0047] In addition, the surface of the twin helical shaft, the inner wall of the feed hopper 1, the inner wall of the fast discharge pipe 2, the inner wall of the replenishment pipe 7, and the inner wall of the discharge hopper 5 are all treated with DLC coating technology to form a wear-resistant and non-adhesive coating.

[0048] like Figure 4 A brief description of our organization's work process: The working process of this device strictly follows the logic of "rapid feeding - precise replenishment - stable output". The specific steps are as follows, and the entire process is automated by a PLC control system, requiring no manual intervention: 1. Preparation stage: Load the nano-sized tungsten carbide powder to be fed into the feed hopper 1. The control system presets the feeding weight standard (set according to production needs). At the same time, adjust the operating parameters of the large spiral shaft drive servo motor 10 and the small spiral shaft drive servo motor 9 to ensure that the air disc 8 and air hammer 6 are in normal working condition. At this time, the fast feeding large spiral shaft 3 and the replenishing small spiral shaft 4 are both in the stopped state, and the air disc 8 and air hammer 6 are in the standby state.

[0049] 2. Rapid feeding stage: When the control system receives the feeding command, it immediately sends a start signal to the large spiral shaft drive servo motor 10. The large spiral shaft drive servo motor 10 starts and drives the rapid feeding large spiral shaft 3 to rotate at high speed. The material in the feed hopper 1 passes through the rapid feeding pipe 2 and is pushed down to the discharge hopper 5 by the rapid feeding large spiral shaft 3, and then conveyed to the subsequent packaging equipment. This stage is rapid feeding, which aims to quickly convey about 90% of the preset weight value to ensure feeding efficiency.

[0050] 3. Precise Feeding Stage: When the weighing mechanism of the subsequent packaging equipment (not shown, used in conjunction with this mechanism) detects that the material weight has reached 90% of the preset weight value, it immediately sends a signal to the control system. After receiving the signal, the control system sends a stop signal to the large spiral shaft drive servo motor 10, and the large spiral shaft 3 stops rotating, ending the rapid feeding stage. At the same time, the control system sends a start signal to the small spiral shaft drive servo motor 9, which starts and drives the small feeding spiral shaft 4 to rotate. The remaining material in the feed hopper 1 slowly falls into the discharge hopper 5 through the feeding pipe 7 under the pushing action of the small feeding spiral shaft 4. When the material weight is about to reach the preset weight value (such as reaching 98% of the preset weight value), the control system controls the small spiral shaft drive servo motor 9 to switch to low-speed or jogging control mode. The small feeding spiral shaft 4 rotates at low speed or intermittently, realizing micro-precise feeding and gradually approaching the preset weight value.

[0051] 4. Stable Discharge and Auxiliary Protection Stage: Throughout the feeding process, the air disc 8 operates intermittently (starting once every preset time interval) to break up air pockets and corner accumulations formed by material in the feed hopper 1, ensuring a stable material flow. Simultaneously, the air hammer 6 operates intermittently, striking the wall of the discharge hopper 5 to prevent material from adhering to the inner wall of the discharge hopper 5 and avoiding collapse-style material discharge. When the weighing mechanism detects that the material weight has reached the preset weight value, it immediately sends a signal to the control system. The control system then sends a stop signal to the small spiral shaft drive servo motor 9, stopping the rotation of the small feeding spiral shaft 4, thus ending the precise feeding stage.

[0052] 5. Cyclic working stage: After a single feeding is completed, the control system controls the air disc 8 and air hammer 6 to stop working and wait for the next feeding instruction; when the next feeding instruction is received, the above steps are repeated to achieve continuous, automated and precise feeding, which is suitable for industrial mass production needs.

[0053] Key control descriptions: The core of our precise feeding system lies in differentiated control, specifically as follows: The large spiral shaft drive servo motor 10 uses only "start-stop" control, maintaining a constant high speed during operation to ensure rapid feeding efficiency. The small spiral shaft drive servo motor 9 employs a multi-stage control mode: initially, it uses constant speed control (slower rotation speed); as it approaches the preset weight value, it switches to variable speed control (gradually decreasing rotation speed); finally, it switches to jog control (intermittent rotation). Through this multi-stage control, it achieves micro-volume, precise feeding, ensuring a feeding accuracy of ±10 grams. The operating frequency of the air disc 8 and air hammer 6 can be adjusted according to the looseness and agglomeration of the material, ensuring anti-blocking and anti-sticking effects.

[0054] The second embodiment of the present invention: I. Basic architecture of this embodiment: The mechanism for precise control of tungsten carbide powder feeding in this embodiment includes a feed hopper 1 and a discharge hopper 5; The fast discharge pipe 2 and the replenishment pipe 7 are both connected at their upper ends to the discharge port of the feed hopper 1 and at their lower ends to the feed port of the discharge hopper 5. The large spiral shaft 3 for rapid feeding is installed inside the rapid feeding pipe 2 and is driven by the large spiral shaft drive servo motor 10; The feeding small spiral shaft 4 is installed inside the feeding pipe 7 and is driven by the small spiral shaft drive servo motor 9; the feeding small spiral shaft 4 is a variable diameter shaft, and its feed end diameter is larger than its discharge end diameter; The control system, electrically connected to the large helical shaft drive servo motor 10, the small helical shaft drive servo motor 9, and a downstream weighing mechanism, is configured to perform the following steps: Step 1: Control the start of the servo motor 10 of the large spiral shaft drive to drive the large spiral shaft 3 for rapid feeding; Step 2: Receive feedback from the downstream weighing mechanism. When the weight reaches the first threshold, control the large spiral shaft drive servo motor 10 to stop and control the small spiral shaft drive servo motor 9 to start, driving the feeding small spiral shaft 4 to run in the first mode. Step 3: When the weight reaches the second threshold, control the small spiral shaft drive servo motor 9 to drive the feeding small spiral shaft 4 to run in the second mode. The single feeding amount in the second mode is less than that in the first mode. Step 4: When the weight reaches the target value, control the small spiral shaft drive servo motor 9 to stop.

[0055] In addition, it also includes: Air disc 8 is installed on the inner wall of feed hopper 1 near the discharge port; Air hammer 6 is installed on the outer wall of the hopper 5; The control system is also electrically connected to the air disc 8 and the air hammer 6; During the execution of steps 1 to 4, the control air disc 8 and air hammer 6 operate intermittently.

[0056] It also includes coatings. DLC coatings are provided on the inner walls of the feed hopper 1, the rapid feeding pipe 2, the replenishment pipe 7, the feed hopper 5, as well as on the surfaces of the rapid feeding large spiral shaft 3 and the replenishment small spiral shaft 4. The DLC coatings are prepared by physical vapor deposition process.

[0057] This embodiment integrates a variable-diameter feeding screw shaft, an all-around DLC anti-stick coating, pneumatic active anti-clogging components (air discs, air hammers), and a multi-stage collaborative control method based on weight feedback into a cohesive whole. It is a systematic and proactive solution addressing the "adhesion, agglomeration, and difficulty in precise control" characteristics of nano-sized tungsten carbide powder. Each feature supports the others, working together to achieve a comprehensive effect of "high efficiency, high precision, stability, and long-lasting effectiveness" that cannot be achieved by a single feature.

[0058] The first threshold is 85% to 95% of the target weight, and the second threshold is 95% to 99% of the target weight.

[0059] This specific threshold range is the result of experimental optimization based on the flow characteristics of nano-tungsten carbide powder, and it is key to achieving a balance between efficiency and accuracy. Switching too early (e.g., below 85%) affects efficiency; switching too late (e.g., above 95%) leaves insufficient buffer space, which can easily lead to loss of accuracy control.

[0060] Based on the above, the first threshold is 90% of the target weight, and the second threshold is 98% of the target weight.

[0061] 90% and 98% are optimal values ​​verified through extensive process testing. When approximately 10% of the material remains in the hopper, the internal pressure drops to a critical value. At this point, the strong shear force of the large auger can easily cause undisintegrated agglomerates to undergo uncontrollable overall shear slippage, rather than stable conveying. Therefore, switching to a gentler small auger before this critical point is to avoid triggering abrupt changes in the flow pattern that could lead to loss of precision control. Thus, the 90% switching point provides a sufficient and safe buffer zone for replenishing the small auger shaft; switching to micro-motion mode at 98% provides a crucial fine control stage for achieving the final ±10 gram accuracy.

[0062] The feeding small spiral shaft 4 includes a first diameter end 12 and a second diameter end 14 connected to each other. The diameter of the first diameter end 12 is larger than the diameter of the second diameter end 14, and the lead of the first blade 13 on the first diameter end 12 is smaller than the lead of the second blade 15 on the second diameter end 14.

[0063] A large-diameter end with a small lead provides stable and appropriate feeding in the early stages of feeding; a small-diameter end with a large lead forms a "small-volume, low-inertia" conveying unit in the later stages of feeding, which is the physical basis for achieving micro-precision feeding. This design is a "mechanical self-adaptive" approach to the nonlinear flow characteristics of powder.

[0064] The diameter of the first diameter end 12 of the small spiral shaft is 45~55mm, and the spacing of the first blade 13 of the small spiral shaft is 35~45mm; the diameter of the second diameter end 14 of the small spiral shaft is 30~35mm, and the spacing of the second blade 15 of the small spiral shaft is 55~65mm.

[0065] The diameter of the large spiral shaft 3 for rapid feeding is larger than the diameter of the first diameter end 12 of the small spiral shaft 4 for feeding.

[0066] The dimensional difference between the large and small spiral shafts was clearly defined, ensuring the absolute conveying capacity advantage of the large spiral shaft in the rapid feeding stage. This is the structural basis for realizing the "fast first, then precise" process logic.

[0067] The diameter of the large spiral shaft 3 for rapid feeding is 54~60mm, and the spacing of its large spiral shaft blades 11 is 95~105mm.

[0068] The first mode is a constant speed mode, and the second mode is a low-speed continuous rotation mode or an intermittent jog mode.

[0069] This multi-mode control is a software adaptation specifically designed for the structural characteristics of the variable-diameter screw shaft. The constant speed mode is used during the main feeding stage to ensure efficiency and stability; the low-speed or jogging mode is specifically designed to work with the small-diameter end, achieving "creep" approximation, which is a manifestation of collaborative innovation between software and hardware to achieve ultimate precision.

[0070] II. Core improvements to the components in this embodiment: 1. DLC coating: This addresses the root causes of weight errors, material waste, and accidental collapses caused by powder adhering to the inner walls of equipment.

[0071] Its application and purpose are both unique: it is the first systematic application of nanoscale tungsten carbide powder to prevent adhesion throughout the entire flow channel. Its purpose is not only wear resistance, but more importantly, to reduce surface energy and counteract the van der Waals forces that cause nanoparticle adhesion, thus preventing material residue and collapse-type material drop from a physical source. This is not a simple material replacement, but a disruptive surface engineering solution for a specific material (nanoscale tungsten carbide) and a specific problem (strong adhesion).

[0072] 2. Variable diameter feeding screw shaft: Solve the problem of precise control that makes it difficult to linearly reduce the flow rate at the end of the feeding process and is prone to over-flow.

[0073] Its structure and function are precisely mapped: the coupled design of its variable diameter (large → small) and variable lead (small → large) is not for spatial adaptation, but for accurately simulating and realizing the "coarse-medium-fine" feeding flow curve. In particular, the small diameter section at the end is optimized for the balance point of "agglomerate size" and "flow inertia" when nanopowder is fed in small quantities. It is the core mechanical actuator that achieves an accuracy of ±10 grams, rather than a general conveying component.

[0074] 3. Air discs and air hammers: Actively prevent flow stagnation and adhesion layer accumulation, and maintain dynamic and stable flow, rather than passively dealing with blockages.

[0075] Its precise positioning, timing, and logic: the air disc is located in the critical arch-prone area of ​​the feed hopper, and the air hammer is located in the adhesion-sensitive area of ​​the discharge hopper, both operating intermittently and at low intensity. Its innovation lies in the concept of "preventative micro-intervention," which gently breaks up any arches or adhesion layers as they form, preventing them from developing into "collapses" that affect accuracy. This differs from traditional, high-intensity, continuous vibration-based, coarse-force arch-breaking methods.

[0076] 4. Three-stage control logic: By deeply integrating macroscopic control strategies with microscopic material properties and mechanical performance, a stable and repeatable precision closed loop can be achieved.

[0077] The scientific basis of its threshold setting and the coupling of its control modes: the switching point of "rapid to 90%" is based on experimental understanding of the "critical agglomeration pressure" of nanopowders; the secondary switching of "medium-speed feeding to 98%" and "micro-scale approaching 100%" is deeply bound to the physical characteristics (large and small diameter segments) of the variable diameter screw. The control modes (constant speed, low speed, jogging) are software-hardware collaborative algorithms that are precisely matched with the mechanical output capability of the screw, rather than independent programs.

[0078] III. The cooperative performance of this embodiment: 1. The DLC coating provides a stable physical basis for all subsequent controls. If the DLC coating does not completely suppress adhesion, then: The powder will adhere and fall off irregularly, causing the weighing signal to fluctuate violently and become distorted, rendering any precise control based on weight feedback (such as 90% or 98% switching) impossible.

[0079] The impact of the pneumatic hammer will cause large sections of the adhesive layer to collapse, resulting in catastrophic overshoot, making "precise material replenishment" impossible.

[0080] Collaborative Creativity: The DLC coating is not an isolated improvement, but rather the "foundation" upon which the entire high-precision control system operates stably. It transforms material flow from an "unpredictable sticky-slippery state" to a "predictable dry flow," making subsequent precision control possible. This fundamental and prerequisite role demonstrates that it is an inseparable organic whole with the rest of the system.

[0081] 2. The variable diameter screw and the three-stage control form a closed-loop execution system integrating mechanical and electronic components. If there is only a three-stage control logic but a constant small screw is used, it will still be impossible to provide a sufficiently small and stable flow rate in the 98% to 100% range, and the accuracy will be difficult to reach ±10 grams. Conversely, if there is only a variable diameter screw but no control to switch to micro-motion mode at 98%, the micro-flow advantage of the small diameter range cannot be accurately utilized.

[0082] Collaborative Creativity: The variable-diameter spiral is the "physical embodiment" of control, while the control logic is the spiral's "intelligent brain." The two are specifically designed and matched to each other. The "second threshold (98%)" and "second mode (jogging)" in the control logic are precisely designed to activate and fully utilize the micro-flow characteristics of the "small diameter section" at the end of the variable diameter screw.

[0083] This deep hardware and software coupling design is a customized solution for the specific problem of "how to achieve the ultimate precision filling of the last 2% of weight", rather than a simple connection between a general controller and a general conveyor.

[0084] 3. Pneumatic assistance as a dynamic regulator to maintain "flow stability" DLC coatings solve static adhesion, but cannot completely prevent temporary micro-arches formed by interparticle forces during dynamic processes. The intermittent operation of the air discs and air hammers allows for real-time fine-tuning of stability during the flow process (dynamic).

[0085] Collaborative innovation: Together with the DLC coating, they form a double guarantee of "static anti-sticking" and "dynamic anti-clogging," and together with the control system, they form a dual thread of "main conveying" and "condition maintenance." This combination ensures that the material flow remains in an ideal and controllable state throughout a single feeding cycle that can last for several minutes, providing end-to-end assurance for accuracy.

[0086] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0087] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0088] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A mechanism for precisely controlling the feeding of tungsten carbide powder, comprising a feeding hopper (1) and a discharging hopper (5); characterized in that Further comprising: a fast discharging pipeline (2) and a supplementary feeding pipeline (7), both of which are in communication with the discharge port of the feeding hopper (1) at the upper end, and both of which are in communication with the feeding port of the discharging hopper (5) at the lower end; a fast discharging large screw shaft (3) installed in the fast discharging pipeline (2) and driven by a large screw shaft driving servo motor (10); a supplementary feeding small screw shaft (4) installed in the supplementary feeding pipeline (7) and driven by a small screw shaft driving servo motor (9); the supplementary feeding small screw shaft (4) is a variable diameter shaft, the diameter of the feeding end is larger than that of the discharging end; a control system electrically connected with the large screw shaft driving servo motor (10), the small screw shaft driving servo motor (9) and a downstream weighing mechanism, configured to perform the following steps: Step 1: control the large screw shaft driving servo motor (10) to start, drive the fast discharging large screw shaft (3) to run; Step 2: receive the feedback of the downstream weighing mechanism, when the weight reaches a first threshold value, control the large screw shaft driving servo motor (10) to stop, and control the small screw shaft driving servo motor (9) to start, to drive the supplementary feeding small screw shaft (4) to run in a first mode; Step 3: when the weight reaches a second threshold value, control the small screw shaft driving servo motor (9) to drive the supplementary feeding small screw shaft (4) to run in a second mode, the single feeding amount of the second mode is smaller than that of the first mode; Step 4: when the weight reaches a target value, control the small screw shaft driving servo motor (9) to stop.

2. A mechanism for precision controlled feeding of tungsten carbide powder as claimed in claim 1, wherein, Further comprising: an air disc (8) installed on the inner wall of the feeding hopper (1) near the discharge port; an air hammer (6) installed on the outer wall of the discharging hopper (5); the control system is also electrically connected with the air disc (8) and the air hammer (6); during the execution of steps 1 to 4, control the air disc (8) and the air hammer (6) to work intermittently.

3. A mechanism for precision controlled feeding of tungsten carbide powder as claimed in claim 1, wherein, The first threshold value is 85% to 95% of the target weight, and the second threshold value is 95% to 99% of the target weight.

4. A mechanism for precision controlled feeding of tungsten carbide powder as claimed in claim 3 wherein, The first threshold value is 90% of the target weight, and the second threshold value is 98% of the target weight.

5. A mechanism for precision controlled feeding of tungsten carbide powder as claimed in claim 1, wherein, The supplementary feeding small screw shaft (4) comprises a small screw shaft first diameter end (12) and a small screw shaft second diameter end (14) connected in series, the diameter of the small screw shaft first diameter end (12) is larger than that of the small screw shaft second diameter end (14), and the lead of the small screw shaft first blade (13) on the small screw shaft first diameter end (12) is smaller than that of the small screw shaft second blade (15) on the small screw shaft second diameter end (14).

6. A mechanism for precision controlled feeding of tungsten carbide powder as claimed in claim 5 wherein, The diameter of the small screw shaft first diameter end (12) is 45-55mm, and the pitch of the small screw shaft first blade (13) is 35-45mm; the diameter of the small screw shaft second diameter end (14) is 30-35mm, and the pitch of the small screw shaft second blade (15) is 55-65mm.

7. A mechanism for precision controlled feeding of tungsten carbide powder as claimed in claim 1, wherein, The first mode is constant speed mode, and the second mode is low-speed continuous rotation mode or intermittent point mode.

8. A mechanism for precision controlled feeding of tungsten carbide powder as claimed in claim 1, wherein, The diameter of the fast discharging large spiral shaft (3) is greater than the diameter of the small spiral shaft first diameter end (12) of the small spiral shaft (4).

9. A mechanism for precision controlled feeding of tungsten carbide powder as claimed in claim 8, wherein, The diameter of the fast discharging large spiral shaft (3) is 54-60 mm, and the pitch of the large spiral shaft blade (11) is 95-105 mm.

10. A mechanism for precision controlled feeding of tungsten carbide powder as claimed in claim 1, wherein, The inner walls of the feeding hopper (1), the fast discharging pipeline (2), the feeding pipeline (7), the discharging hopper (5), and the surfaces of the fast discharging large spiral shaft (3) and the feeding small spiral shaft (4) are provided with DLC coating, and the DLC coating is prepared by physical vapor deposition process.

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