Multistage abrasive microdivision line and method of production thereof

Abstract

This application relates to the field of abrasive production technology, and in particular to a multi-stage abrasive differential production line and its production method, including a multi-stage separator, a mixing and batching system, and a PLC controller. The multi-stage separator includes at least three grading units connected in series along the material flow direction. The first-stage grading unit has a mixing raw material inlet for feeding raw materials with a particle size range of 1~30μm in a single operation. Each grading unit has a single-particle-size outlet. The mixing and batching system includes multiple buffer silos, metering feeders, and a mixer. The PLC controller calculates the discharge ratio of each buffer silo according to the particle size distribution required for the target finished product, and controls the corresponding metering feeders to feed materials to the mixer according to the specified ratio. This allows for the mixing of multiple single-particle-size products in any proportion, quickly obtaining specific abrasive finished products with custom particle size distributions such as single-peak, bi-peak, or multi-modal, adapting to different processing needs.

Description

Technical Field

[0001] This application relates to the field of abrasive production technology, and in particular to a multi-stage abrasive differential production line and its production method. Background Technology

[0002] The particle size distribution of abrasives is one of the core parameters determining workpiece surface quality and processing efficiency. In precision grinding, lapping, and polishing, the hardness, brittleness, and surface finish requirements of workpiece materials vary, leading to increasingly diverse demands for abrasive particle size distribution. For hard and brittle workpiece materials, using a single-size abrasive often fails to balance processing efficiency and surface quality—overly coarse abrasives cause deep scratches and subsurface damage during processing, while overly fine abrasives result in insufficient cutting force and low grinding efficiency. In recent years, abrasives with bimodal or multimodal particle size distributions have gradually attracted industry attention. By mixing coarse and fine particles in a certain proportion, a synergistic effect of "coarse particles for efficient cutting and fine particles for polishing and finishing" can be achieved, breaking through the bottleneck of single-size abrasives in terms of processing efficiency.

[0003] In existing technologies, abrasive production typically follows a process route of "first mixing raw materials, then crushing and grinding, and finally classifying and sorting." For example, Chinese patent CN102241959A discloses a method for producing mixed abrasive materials, which involves mixing zirconium silicate and alumina, ball milling the mixture, and then obtaining different grades of microparticles through repeated static sedimentation and siphoning. Another example is Chinese patent CN107511248A, which discloses a process method for crushing and single-machine sorting of multiple products. After crushing the material to be processed, a single-machine sorting device is used for multi-stage sorting to collect products of various particle sizes. Furthermore, existing technologies such as continuous grading devices for diamond micron powder (patent CN202211559973) and production systems for segmented micron powder (utility model CN200920140946) also feature multi-stage sorting structures and can produce products of various particle sizes.

[0004] After sorting products into different particle sizes, each particle size is treated as an independent product category and packaged or stored separately. The mixing process between products of different particle sizes is considered an "adjustment after the fact" or "unnecessary" operation on the production line. In fact, the requirements of downstream applications for abrasive particle size distribution are changing. Different processed materials and processing procedures with different precision require different abrasive particle size distributions. Sometimes narrowly distributed medium and fine particles are needed to obtain uniform surface quality, while other times a widely distributed or bimodal mixed particle distribution is needed to balance efficiency and precision.

[0005] However, the aforementioned existing technologies generally share a common drawback: The traditional "mix first, then sort" process is a passive process - once the raw material ratio is determined, the product distribution of the graded product is also fixed and cannot be flexibly adjusted according to the changing market demand. The "crush first, grade, then simply package" process can only obtain one particle size product at the end of the grading process, and cannot meet the requirement of "actively remixing multiple single particle size products after sorting to customize a specific particle size distribution", lacking the corresponding process design and equipment configuration. Summary of the Invention

[0006] This application provides a multi-stage abrasive differential production line and its production method to improve the following technical problems: the existing technology cannot meet the requirement of "actively remixing multiple single-size products after sorting to customize a specific particle size distribution", and lacks corresponding process design and equipment configuration.

[0007] In a first aspect, this application provides a multi-stage abrasive differential production line, which adopts the following technical solution: A multi-stage abrasive differential production line includes a multi-stage separator, a mixing and batching system, and a PLC controller, characterized in that: The multi-stage separator includes at least three grading units connected in series along the material flow direction. The first-stage grading unit is provided with a mixed raw material inlet for feeding abrasive raw materials with a particle size range of 1~30μm in one go. Each grading unit is provided with a single-particle-size outlet for outputting the single-particle-size product obtained from that stage of grading. A feeding pipe is provided between adjacent grading units, and the remaining coarse powder material of the previous grading unit automatically enters the next grading unit for further grading through the feeding pipe. The mixing and batching system includes: multiple buffer silos corresponding one-to-one with the single-size discharge ports, a metering feeder installed at the outlet of each buffer silo, and a mixer that receives materials from all the metering feeders; The PLC controller calculates the discharge ratio of each buffer hopper based on the particle size distribution required for the target finished product, and controls the corresponding metering feeder to feed materials to the mixer according to the ratio.

[0008] In one feasible technical solution of this application, each grading unit is an air classifier, and the grading wheel speed of the air classifier is independently adjusted by the PLC controller to change the cutting particle size of that level of sorting; the PLC controller has at least three custom particle size distribution templates pre-stored inside, each template corresponding to: a set of grading wheel speed setting values ​​for each grading unit and a set of discharge ratio coefficients for each buffer hopper.

[0009] In one feasible technical solution of this application, an online particle size detection probe is installed at the single particle size discharge port. The online particle size detection probe is used to transmit the detected actual particle size data to the PLC controller in real time. The PLC controller is used to compare the actual particle size with the theoretical set value. If the deviation exceeds the allowable range, the speed of the classifying wheel corresponding to the classifying unit is automatically adjusted.

[0010] In one feasible technical solution of this application, the mixer is a V-type convection mixer or a three-dimensional oscillating mixer. The mixer is equipped with staggered baffles inside. An online particle size analyzer is installed at the discharge port of the mixer. The online particle size analyzer is electrically connected to the PLC controller and feeds back the particle size distribution data of the finished product to the PLC controller.

[0011] In one feasible technical solution of this application, the PLC controller is provided with a closed-loop adjustment module, which simultaneously receives signals from the finished product particle size online detector and all the online particle size detection probes; when the finished product particle size distribution deviates from the target value, the closed-loop adjustment module first corrects it by adjusting the discharge ratio of each of the buffer hoppers. If the target cannot be met after correction, the rotation speed of the grading wheel of the corresponding grading unit is adjusted in reverse order.

[0012] In one feasible technical solution of this application, a raw material premixing device is also provided upstream of the multi-stage separator. The raw material premixing device mixes abrasive raw materials with different particle sizes in the range of 1~30μm at a set initial mass ratio in one go, and then sends them into the mixing raw material inlet of the first-stage classification unit. The initial mass ratio is positively correlated with the mass ratio of the corresponding particle size range in the particle size distribution of the target finished product.

[0013] In one feasible technical solution of this application, the multi-stage sorter includes at least four grading units and sequentially produces at least four single-size products with particle sizes ranging from 1~3μm, 3~6μm, 6~12μm, 12~20μm and 20~30μm; the number of buffer bins is equal to the number of single-size products actually produced.

[0014] Secondly, this application provides a multi-stage abrasive differential production method, which adopts the following technical solution: A multi-stage abrasive differential production method, based on the multi-stage abrasive differential production line as described above, includes the following steps: Abrasive raw materials with a particle size range of 1~30μm are mixed and fed into the first-stage classification unit of a multi-stage separator in one go; By screening through at least three grading units, a single particle size product is obtained from each grading unit. Based on the preset custom particle size distribution requirements of the target abrasive finished product, the mass ratio of each single particle size product during mixing is calculated using linear programming or particle size distribution fitting algorithm. According to the specified mass ratio, materials are simultaneously fed from the corresponding buffer silos into the mixer and mixed evenly to obtain the finished abrasive product.

[0015] In one feasible technical solution of this application, after the abrasive product is obtained by mixing, the particle size of the product is detected online, and the actual particle size distribution detected is compared with the custom particle size distribution requirement. If the deviation between the two exceeds the allowable range, the discharge ratio of each buffer hopper is automatically adjusted. If the deviation still exceeds the standard after adjusting the discharge ratio, the rotation speed of the classifying wheel of at least one classifying unit is further adjusted until the particle size distribution of the product meets the standard.

[0016] In one feasible technical solution of this application, when calculating the mixing ratio, the objective function is to minimize the mean square error between the finished particle size distribution and the target distribution, and the constraint is that the amount of each single particle size product is non-negative and the sum is 1. The mass ratio is obtained by solving the problem through linear programming. Furthermore, in the raw material input stage, the mass ratio of each original particle size is pre-set to be positively correlated with the mass ratio of each particle size interval in the target distribution.

[0017] In summary, this application includes at least one of the following beneficial technical effects: Multiple single-size products separated by sorting can be mixed in any proportion to quickly obtain specific abrasive finished products with custom particle size distributions such as single-peak, double-peak, or multi-modal, adapting to different processing needs without changing equipment; changing the existing passive mode of "mixing raw materials first and then classifying", the particle size distribution of the finished product is actively determined by the mixing ratio at the back end, and switching specifications only requires modifying the PLC controller parameters, which greatly improves production flexibility; the multi-stage series classification units work synchronously, and multiple particle size products can be produced in one pass without the need for re-grinding, shortening the process and reducing energy consumption and equipment wear; Meanwhile, the PLC controller can precisely control the discharge ratio of each hopper, with small particle size distribution errors between batches, meeting the consistency requirements of precision machining; the buffer hopper and the metering feeder constitute a programmable batching system, which can be used with an online detector to achieve feedback correction, compensate for upstream particle size drift, maintain the stability of the finished product, and can also be upgraded by adding a downstream mixing and batching system on the basis of existing grading equipment without replacing the original equipment, making it highly practical. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the principle of a multi-stage abrasive differential production line according to an embodiment of this application; Figure 2 This is a schematic flowchart of the multi-stage abrasive differential production method according to an embodiment of this application.

[0020] Explanation of reference numerals in the attached figures: 10. Multi-stage sorter; 11. Grading unit; 12. Feeding pipe; 13. Online particle size detection probe; 20. Mixing and batching system; 21. Buffer silo; 22. Metering feeder; 23. Mixer; 24. Online particle size detector for finished product; 30. PLC controller; 40. Raw material premixing device. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application.

[0022] Definitions of terms that need to be explained in advance: When a component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or indirectly on that other component; When a component is referred to as being "connected to" another component, it can be directly or indirectly connected to that other component; The terms “length”, “width”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer”, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the attached drawings, and are only for the convenience of description, and do not indicate or imply that there must be a specific orientation. The terms “first” and “second” are used only to distinguish different components and do not indicate importance or quantity. Unless otherwise expressly defined, “multiple” means two or more.

[0023] The following is in conjunction with the appendix Figure 1-2 This application will be described in further detail.

[0024] Reference Figure 1 This embodiment provides a multi-stage abrasive differential production line, including a multi-stage separator 10, a mixing and batching system 20, an industrial-grade PLC controller 30, and a raw material premixing device 40.

[0025] The multi-stage classifier 10 adopts the principle of airflow classification, and four classification units 11 are connected in series along the material flow direction. The series connection of multi-stage classifiers is a conventional technical means in this field. For example, existing vertical airflow classifiers generally support multiple series connection structures, which can classify products of multiple particle size ranges at the same time and obtain ideal particle size distribution.

[0026] The first classification unit 11 (primary classifier) ​​has a mixed raw material inlet for feeding abrasive raw materials with a particle size range of 1μm to 30μm in a single operation. Each classification unit 11 has a single particle size outlet and a coarse powder outlet. A sealed feed pipe 12 is provided between adjacent classification units 11, through which the remaining coarse powder material from the previous classification unit 11 automatically enters the next classification unit 11 for further sorting. The single particle size products produced by the four classification units 11 in sequence are: 1~3μm (primary fine powder), 3~6μm (secondary fine powder), 6~12μm (tertiary fine powder), and 12~20μm (quaternary fine powder). The remaining 20~30μm coarse powder is discharged from the bottom of the final classification unit 11 and can be stored or returned.

[0027] It should be noted that the above four-stage sorting configuration is only an example. In actual production, the number of grading units 11 (at least three stages) and the cutting particle size setting of each stage can be flexibly adjusted according to the particle size range requirements of the target product and the properties of the raw materials. For example, when the proportion of particles larger than 20μm in the raw material is low, the final cutting particle size can be set to 18μm to optimize the sorting efficiency.

[0028] The mixing and batching system 20 includes: four buffer silos 21 corresponding one-to-one with the four single-size discharge ports mentioned above; a metering feeder 22 (such as a screw feeder or belt scale feeder) installed at the outlet of each buffer silo 21; and a mixer 23 that receives materials from all the metering feeders 22. The number of buffer silos 21 is equal to the actual number of single-size products produced, to ensure that each single-size product can be stored independently and dispensed on demand.

[0029] Mixer 23 adopts a V-type convection mixer. Due to its unique container structure, the V-type mixer causes materials to repeatedly aggregate and disperse under the action of gravity and centrifugal force during rotation, achieving axial and radial mixing. It can adapt to the mixing of various materials, and the mixing uniformity can reach over 98%. As an alternative, a three-dimensional oscillating mixer can also be used. This machine uses a drive shaft to drive the cylinder to perform parallel movement and rocking motion, causing the materials to move in three directions (circumferential, radial, and axial) along the cylinder, realizing the flow, dispersion, and mixing of various materials, and achieving a mixing uniformity of over 99.5%.

[0030] The PLC controller 30 uses a Siemens S7-1200 series PLC, with a built-in PID control module and recipe management function. Operators input the desired particle size distribution curve for the target finished product via a host computer HMI touchscreen (e.g., a specific single-peak distribution with target D10=3μm, D50=8μm, D90=18μm, or a bimodal distribution with peaks at 5μm and 15μm). The PLC controller 30 automatically calculates the discharge ratio of each buffer hopper 21 based on a preset mathematical model and outputs a 4-20mA analog control signal to the corresponding metering feeder 22, controlling it to synchronously feed material to the mixer 23 according to the specified ratio. After feeding is completed, the mixer 23 runs for a preset time (usually 15-30 minutes), resulting in an abrasive product with a customized particle size distribution.

[0031] The workflow of the production line in this embodiment can be summarized as follows: Abrasive raw materials with a particle size of 1~30μm are mixed and fed into the first-level classification unit 11 of the multi-stage separator 10 at one time → The four-level classification unit 11 simultaneously sorts out four single-particle-size products → Each single-particle-size product enters the corresponding buffer bin 21 for temporary storage → The PLC controller 30 calculates and controls the metering feeder 22 to feed materials to the mixer 23 in a proportional and synchronous manner according to the target particle size distribution → The mixer 23 mixes evenly to obtain the finished abrasive product.

[0032] The rotational speed of the classifying wheel in each stage of the air classifier is independently adjusted by the PLC controller 30 to change the cutting particle size of that stage. The relationship between the classifying wheel rotational speed and the cutting particle size is determined by the fluid dynamics model of the air classifier—the higher the rotational speed, the greater the centrifugal force, the finer the particles passing through, and the smaller the cutting particle size; conversely, the lower the rotational speed, the coarser the particles passing through, and the larger the cutting particle size.

[0033] The PLC controller 30 has three pre-stored custom particle size distribution templates, each corresponding to a typical application scenario: Template A (narrow distribution type, suitable for precision polishing): First-stage classification speed of 4800 rpm corresponds to a cutting particle size of 3μm, second-stage classification speed of 3600 rpm corresponds to a cutting particle size of 6μm, third-stage classification speed of 2400 rpm corresponds to a cutting particle size of 12μm, and fourth-stage classification speed of 1800 rpm corresponds to a cutting particle size of 20μm; the discharge ratio coefficients of each buffer hopper 21 are α1=0.70, α2=0.30, and the rest are 0, that is, it is mainly composed of two kinds of fine powders of 1~3μm and 3~6μm; Template B (wide distribution type, suitable for high-efficiency coarse grinding): the first-stage classification speed of 4200 rpm corresponds to a cutting particle size of 5μm, the second-stage classification speed of 3000 rpm corresponds to a cutting particle size of 9μm, the third-stage classification speed of 1800 rpm corresponds to a cutting particle size of 18μm, and the fourth-stage classification speed of 1200 rpm corresponds to a cutting particle size of 25μm; the discharge ratio coefficients of each buffer hopper 21 are α1=0.15, α2=0.35, α3=0.35, and α4=0.15, respectively; Template C (bimodal distribution type, suitable for composite processing that balances efficiency and precision): The speed setting of the grading wheel is the same as that of template A; the discharge ratio coefficients of each buffer hopper 21 are α1=0.40, α2=0.10, α3=0.40, and α4=0.10, respectively, forming a bimodal effect with high peaks on both sides and low peaks in the middle for coarse powder (1~3μm and 6~12μm).

[0034] Operators can call up the required templates with one click on the touch screen according to the order requirements. The PLC controller 30 automatically adjusts the speed of the grading wheel of each grading unit 11 and the discharge ratio coefficient of each metering feeder 22 to the corresponding set value at the same time. There is no need for manual setting of each item, which greatly reduces the downtime for debugging when switching product specifications.

[0035] Furthermore, an online particle size detection probe 13 is installed at the single-particle-size discharge port of each grading unit 11. The online particle size detection probe 13 is an online laser particle size detection probe (e.g., Baxter BT-Online1 or Zhenli Optics PAT-link series). This probe uses laser scattering technology and automatically extracts powder samples from the discharge pipe for particle size testing using Venturi technology. The testing frequency can be set to once every 5-10 minutes. The tested samples are directly returned to the production line pipeline, with no material loss. The detection probe transmits the actual single-particle-size data (including key particle size indicators such as D10, D50, and D90) to the PLC controller 30 in real time via RS485 bus.

[0036] The PLC controller 30 compares the received actual single-particle size data with the theoretically set cutting particle size of the corresponding grading unit 11 and calculates the deviation value. If the deviation exceeds the preset allowable range (e.g., D50 deviation exceeds ±1.5μm), the PLC controller 30 automatically outputs an adjustment signal through a PID algorithm to drive the frequency converter to adjust the grading wheel speed of the corresponding grading unit 11—increasing the speed when the actual particle size is coarser and decreasing the speed when it is finer—until the actual particle size returns to the allowable range of the theoretically set value. This ensures that each grading unit 11 can independently resist particle size drift caused by disturbances such as grading wheel wear, feed fluctuations, or changes in air source pressure, ensuring long-term stability of single-particle-size products.

[0037] Specifically, a closed-loop adjustment module is set in the PLC controller 30. The closed-loop adjustment module simultaneously receives signals from the finished product particle size online detector 24 and the online particle size detection probes 13 at all single particle size outlets, so as to realize the coordinated adjustment of the two levels of production line grading and mixing.

[0038] The finished product particle size online detector 24 is installed at the discharge port of the mixer 23. It also uses an online laser particle size analyzer to monitor the actual particle size distribution data of the final abrasive product in real time and feed the data back to the PLC controller 30.

[0039] When the PLC controller 30 detects that the finished product particle size distribution deviates from the target value through the finished product particle size online detector 24, the closed-loop control module adopts a two-level control strategy: First level (prioritizing mixing ratio adjustment): The PLC controller 30 first maintains the rotational speed of the classifying wheels in each classifying unit 11 unchanged. Based on the deviation between the actual particle size distribution of the finished product and the target distribution, it recalculates the discharge ratio of each buffer hopper 21 through linear programming and sends the corrected control signal to each metering feeder 22. For example, if the fine powder content in the finished product is higher than the target value, the PLC controller 30 correspondingly lowers the discharge ratio coefficient of the 1~3μm buffer hopper 21 and simultaneously raises the discharge ratio coefficient of the 3~6μm or 6~12μm buffer hopper 21. Since the metering feeder 22 has a fast response speed (usually completing the adjustment within a few seconds), this level of adjustment can quickly correct the deviation of the mixing ratio without affecting the stable operation of the upstream classifying unit 11.

[0040] The second level (reverse adjustment grading unit 11): If the particle size distribution deviation of the finished product still exceeds the allowable range after adjustment at the first level, it indicates that the particle size of a certain level or multiple levels of single-size products has undergone systematic drift (e.g., due to wear of the grading wheel causing the overall cutting particle size to become coarser). At this time, the closed-loop adjustment module adjusts the grading wheel speed of the corresponding level grading unit 11 in reverse order, starting from the downstream and then moving upstream. Specifically, if the particle size of the 6~12μm product is found to be generally too coarse, the grading wheel speed of the third-level grading unit 11 that produces this product is adjusted first; if the adjustment still does not meet the standard, the second-level and first-level grading units 11 are then adjusted upstream in sequence. This reverse adjustment sequence avoids the disturbance to the entire system caused by large adjustments from the upstream, greatly improving the adaptability of the production line.

[0041] A raw material premixing device 40 is added upstream of the multi-stage separator 10 to pre-treat the input abrasive raw materials. The raw material premixing device 40 can be a V-type mixer 23 or a three-dimensional oscillating mixer 23. Its input end receives abrasive raw materials with different particle sizes in the range of 1~30μm, and its output end is connected to the mixing raw material inlet of the first-stage classification unit 11. The raw material premixing device 40 mixes the abrasive raw materials of various particle sizes uniformly at a set initial mass ratio in one go before sending them to the first-stage classification unit 11.

[0042] The initial mass ratio is positively correlated with the mass ratio of each corresponding particle size range in the target finished product particle size distribution. For example, if the target finished product particle size distribution requires a higher content of 3~6μm particles, the proportion of raw materials in the 3~6μm particle size range in the mixed raw materials is increased in advance during the raw material input stage. Through this positive correlation design between the premixing and final mixing ratios, on the one hand, the adjustment pressure of the buffer silo 21 in the subsequent mixing and batching system 20 is reduced, and on the other hand, the particle size distribution of the incoming materials in each grading unit 11 is made more uniform and stable, which helps to improve the grading efficiency. When the distribution of each particle size range in the raw material matches the load of the subsequent sorting, the amount of material retained in each grading unit 11 tends to be balanced, avoiding the occurrence of overload or idling in a certain stage.

[0043] Specifically, the multi-stage separator 10 includes a four-stage classification unit 11, which sequentially produces at least four single-size products with particle sizes ranging from 1~3μm, 3~6μm, 6~12μm, 12~20μm, and 20~30μm. In a typical configuration of this embodiment, the four-stage classification unit 11 actually produces four single-size products (1~3μm, 3~6μm, 6~12μm, and 12~20μm), and the remaining coarse powder of 20~30μm is discharged from the bottom of the final classification unit 11, which can be collected separately as a secondary product or used for other purposes.

[0044] If the target finished product needs to include particles in the 20~30μm particle size range, the sorting parameters of the final grading unit 11 can be further adjusted in the fourth-level grading unit 11 to set the cutting particle size to greater than 30μm. This allows particles of 20~30μm to be output from the outlet of the final grading unit 11 as a single-size product. At this time, the number of buffer bins 21 increases accordingly to five (which is equal to the actual number of single-size products produced). This modular configuration approach allows the production line to flexibly adjust the number of output varieties according to different order requirements, balancing production efficiency and product diversity.

[0045] Reference Figure 1 and Figure 2 Based on the above-mentioned multi-stage abrasive differential production line, this embodiment also provides a multi-stage abrasive differential production method, which specifically includes the following steps: Step S1: Abrasive raw materials with a particle size range of 1~30μm are mixed and fed into the first-stage classification unit 11 of the multi-stage separator 10 in one go; Step S2: Through at least three grading units 11, a single particle size product is obtained from each grading unit 11. The remaining coarse powder material of the previous grading unit 11 is automatically fed into the next grading unit 11 through the feeding pipe 12 for further sorting until the final coarse powder is discharged from the bottom of the last grading unit 11. Step S3: Based on the pre-defined custom particle size distribution requirements of the target abrasive product, calculate the mass ratio of each individual particle size product during mixing using a linear programming algorithm or a particle size distribution fitting algorithm. The custom particle size distribution requirements specifically include at least two particle size ranges and the corresponding mass percentage for each range (e.g., 30% for the 3~6μm range, 50% for the 6~12μm range, and 20% for the 12~20μm range). The pre-defined mixing ratio can be solved using linear programming—with the objective function being the minimum fitting error between the finished particle size distribution and the target distribution, and the constraint that the amount of each individual particle size product is non-negative and its sum is 1, to obtain the optimal mixing ratio. Step S4: According to the mass ratio calculated in step S3, feed the material from the corresponding buffer silo 21 to the mixer 23 simultaneously through the metering feeder 22. After the mixer 23 mixes the materials evenly, the finished abrasive product is obtained. Step S5: After the abrasive product is obtained by mixing in step S4, the particle size of the product is detected online, and the detected actual particle size distribution is compared with the custom particle size distribution requirements in step S3.

[0046] If the deviation between the two exceeds the allowable range (for example, the mass percentage deviation of a certain particle size range exceeds ±2%), the discharge ratio of each buffer hopper 21 will be automatically adjusted for correction. Specifically, the PLC controller 30 recalculates the corrected discharge ratio through linear programming based on the deviation between the actual particle size distribution of the finished product and the target distribution, and sends the updated control signal to each metering feeder 22.

[0047] If the deviation still exceeds the standard after adjusting the discharge ratio, it indicates that the particle size of a certain grade of single-size product has drifted. In this case, the rotation speed of the classifying wheel in at least one classifying unit 11 should be further adjusted until the particle size distribution of the finished product meets the standard. The adjustment sequence adopts a reverse sequential strategy—starting with the classifying unit 11 corresponding to the drifted particle size, and if it is ineffective, gradually extending to the upstream classifying unit 11.

[0048] When calculating the mixing ratio, the objective function is to minimize the mean square error (MSE) between the finished product particle size distribution and the target distribution. The constraint is that the amount of each individual particle size product is non-negative and their sum is 1. The mass ratios are obtained through linear programming. Specifically, let the actual particle size distribution data of the finished product be vector P-actual, and the target particle size distribution be vector P-target. The objective is to minimize Σ(P-actual–P-target)^2. The linear programming solution can be implemented using general tools such as Excel Solver or Matlab-linprog. Using the particle size distribution data of the eleventh-level basic powder as input, the optimal mixing ratio can be obtained.

[0049] Simultaneously, during the raw material input stage, the mass ratio of each native particle size is pre-set to be positively correlated with the mass ratio of each particle size range in the target distribution. For example, if the target mass ratio of the 3~6μm range in the target finished product particle size distribution is 35%, then the proportion of raw materials in the 3~6μm particle size range is preset to be within the range of 30%~40% during raw material premixing. This positive correlation setting matches the load of each classification unit 11 with the raw material distribution, reduces unnecessary material circulation, and further improves classification efficiency.

[0050] The beneficial effects of the multi-stage abrasive differential production line and its production method in this embodiment are as follows: Multiple single-size products separated by sorting can be mixed in any proportion to quickly obtain specific abrasive finished products with custom particle size distributions such as single-peak, double-peak, or multi-modal, adapting to different processing needs without changing equipment; changing the existing passive mode of "mixing raw materials first and then classifying", the particle size distribution of the finished product is actively determined by the mixing ratio at the back end, and switching specifications only requires modifying the PLC controller 30 parameters, which greatly improves production flexibility; the multi-stage series classification unit 11 works synchronously, and multiple particle size products can be produced in one pass without the need for re-grinding, shortening the process and reducing energy consumption and equipment wear; Meanwhile, the PLC controller 30 can accurately control the discharge ratio of each hopper, with small particle size distribution error between batches, meeting the consistency requirements of precision machining; the buffer hopper 21 and the metering feeder 22 constitute a programmable batching system, which can be used with an online detector to achieve feedback correction, compensate for upstream particle size drift, maintain the stability of finished products, and can also be upgraded by adding a downstream mixing and batching system 20 to the existing grading equipment without replacing the original equipment, making it highly practical.

[0051] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A multi-stage abrasive differential production line, comprising a multi-stage separator (10), a mixing and batching system (20), and a PLC controller (30), characterized in that: The multi-stage separator (10) includes at least three grading units (11) connected in series along the material flow direction. The first-stage grading unit (11) is provided with a mixed raw material inlet for feeding abrasive raw materials with a particle size range of 1~30μm at one time. Each grading unit (11) is provided with a single particle size outlet for outputting the single particle size product obtained by that stage of grading. A feeding pipe (12) is provided between adjacent grading units (11), and the remaining coarse powder material of the previous grading unit (11) automatically enters the next grading unit (11) through the feeding pipe (12) for further grading. The mixing and batching system (20) includes: multiple buffer silos (21) corresponding one-to-one with the single particle size discharge port, a metering feeder (22) set at the outlet of each buffer silo (21), and a mixer (23) that receives the material from all the metering feeders (22); The PLC controller (30) calculates the discharge ratio of each buffer hopper (21) according to the particle size distribution required for the target finished product, and controls the corresponding metering feeder (22) to feed the material to the mixer (23) according to the ratio.

2. The multi-stage abrasive differential production line according to claim 1, characterized in that: Each grading unit (11) is an air classifier. The grading wheel speed of the air classifier is independently adjusted by the PLC controller (30) to change the cutting particle size of the classifier. The PLC controller (30) has at least three custom particle size distribution templates pre-stored inside. Each template corresponds to: a set of grading wheel speed settings for each grading unit (11) and a set of discharge ratio coefficients for each buffer silo (21).

3. The multi-stage abrasive differential production line according to claim 2, characterized in that: An online particle size detection probe (13) is installed at the single particle size discharge port. The online particle size detection probe (13) is used to transmit the detected actual particle size data to the PLC controller (30) in real time. The PLC controller (30) is used to compare the actual particle size with the theoretical set value. If the deviation exceeds the allowable range, the speed of the classifying wheel of the corresponding classifying unit (11) is automatically adjusted.

4. The multi-stage abrasive differential production line according to claim 3, characterized in that: The mixer (23) is a V-type convection mixer or a three-dimensional oscillating mixer. The mixer (23) is equipped with staggered baffles inside. The discharge port of the mixer (23) is equipped with an online particle size analyzer (24). The online particle size analyzer (24) is electrically connected to the PLC controller (30) and feeds back the particle size distribution data of the finished product to the PLC controller (30).

5. The multi-stage abrasive differential production line according to claim 4, characterized in that: The PLC controller (30) is equipped with a closed-loop adjustment module, which simultaneously receives signals from the finished product particle size online detector (24) and all the online particle size detection probes (13). When the finished product particle size distribution deviates from the target value, the closed-loop adjustment module first corrects it by adjusting the discharge ratio of each buffer silo (21). If the target value is still not met after correction, the rotation speed of the grading wheel of the corresponding grading unit (11) is adjusted in reverse order.

6. The multi-stage abrasive differential production line according to claim 1, characterized in that: It also includes a raw material premixing device (40) located upstream of the multi-stage separator (10). The raw material premixing device (40) mixes abrasive raw materials with different particle sizes in the range of 1~30μm at a set initial mass ratio in one go, and then sends them into the mixing raw material inlet of the first-stage classification unit (11). The initial mass ratio is positively correlated with the mass ratio of the corresponding particle size range in the particle size distribution of the target finished product.

7. The multi-stage abrasive differential production line according to claim 1, characterized in that: The multi-stage sorter (10) includes at least four grading units (11) and sequentially produces at least four single-size products with particle sizes ranging from 1~3μm, 3~6μm, 6~12μm, 12~20μm and 20~30μm; the number of buffer bins (21) is equal to the number of single-size products actually produced.

8. A multi-stage abrasive differential production method, characterized in that: Based on the multi-stage abrasive differential production line as described in any one of claims 1 to 7, the method includes the following steps: Abrasive raw materials with a particle size range of 1~30μm are mixed and fed into the first-stage classification unit (11) of a multi-stage separator (10) in one go; By sieving through at least three grading units (11), a single particle size product is obtained from each grading unit (11). Based on the preset custom particle size distribution requirements of the target abrasive finished product, the mass ratio of each single particle size product during mixing is calculated using linear programming or particle size distribution fitting algorithm. According to the mass ratio, the corresponding buffer silo (21) is simultaneously fed into the mixer (23) and mixed evenly to obtain the finished abrasive product.

9. The multi-stage abrasive differential production method according to claim 8, characterized in that: After the abrasive product is obtained by mixing, the particle size of the product is detected online. The actual particle size distribution detected is compared with the custom particle size distribution requirement. If the deviation between the two exceeds the allowable range, the discharge ratio of each buffer hopper (21) is automatically adjusted. If the deviation still exceeds the standard after adjusting the discharge ratio, the speed of the classifying wheel of at least one classifying unit (11) is further adjusted until the particle size distribution of the product meets the standard.

10. The multi-stage abrasive differential production method according to claim 8 or 9, characterized in that: When calculating the mixing ratio, the objective function is to minimize the mean square error between the finished particle size distribution and the target distribution, and the constraint is that the amount of each single particle size product is non-negative and the sum is 1. The mass ratio is obtained by solving the problem through linear programming. Furthermore, in the raw material input stage, the mass ratio of each original particle size is set in advance to be positively correlated with the mass ratio of each particle size interval in the target distribution.

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