Powder metallurgy multi-product intelligent scheduling method and system
By calculating the reference time and hindrance distance of powder metallurgy products in the heating zone, and optimizing the production sequence, the problem of furnace temperature instability in powder metallurgy production was solved, and the stability of product quality and the improvement of production efficiency were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHEJIANG HENGJI YONGXIN NEW MATERIALS CO LTD
- Filing Date
- 2026-06-04
- Publication Date
- 2026-07-03
Smart Images
Figure CN122334901A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of powder metallurgy production scheduling technology. In particular, it relates to an intelligent production scheduling method and system for multiple powder metallurgy products. Background Technology
[0002] Powder metallurgy products require high-temperature sintering in a continuous sintering furnace. The sintering process demands stringent stability of the internal temperature field, as temperature fluctuations directly impact the product's microstructure, mechanical properties, and yield. In multi-product mixed-line production, intelligent product scheduling effectively coordinates the furnace's heat load distribution and suppresses abnormal temperature fluctuations, making it crucial for ensuring stable sintering processes and improving production efficiency and product quality.
[0003] Currently, conventional powder metallurgy production scheduling schemes mostly rely on manual experience or simple sequencing rules, which have significant technical shortcomings: existing technologies struggle to accurately quantify the intensity of transient thermal shock generated after products of different specifications and materials are fed into the furnace, and cannot effectively identify the asymmetric thermal inertia characteristics of the sintering furnace, which is prone to heating up but difficult to cool down. Furthermore, during long-batch continuous production scheduling, the continuous heat absorption of preceding products creates a cumulative heat deficit drift, which existing scheduling logic fails to consider and compensate for. Consequently, production sequences generated based on existing schemes are highly susceptible to frequent furnace temperature instability when put into actual production, ultimately causing significant fluctuations in the sintering quality of batch products and hindering the stable and efficient operation of powder metallurgy production lines. Summary of the Invention
[0004] To address the problems of existing powder metallurgy production scheduling technologies failing to quantify transient thermal shock in products, identify asymmetric thermal inertia of the furnace body, and failing to consider cumulative thermal deficit drift in long production cycles, which can easily lead to furnace temperature instability and product quality fluctuations, this invention provides solutions in the following aspects.
[0005] In the first aspect, a method for intelligent scheduling of multiple products in powder metallurgy includes: acquiring and preprocessing production-related data for powder metallurgy sintering, including product unit mass, specific heat capacity, target sintering temperature, ambient temperature, product surface area and volume, actual effective heat power, and conveyor belt speed; calculating the reference time for each product to occupy the heating zone based on the preprocessed production-related data, and calculating the basic blocking distance between adjacent products based on the reference time difference between adjacent products, the global reference time, and the asymmetry coefficient; quantifying the cumulative thermal potential energy drift rate based on the total deviation of the product reference time in the scheduling sequence, and correcting the basic blocking distance using the cumulative thermal potential energy drift rate to obtain the actual blocking distance between adjacent products; constructing an objective function and solving for the optimal scheduling sequence with the minimum sum of all actual blocking distances in the scheduling sequence as the optimization objective, and issuing the optimal scheduling sequence for execution and supporting dynamic rescheduling.
[0006] Preferably, the reference time for each product to occupy the heating zone includes: Taking any product as the target product, the total effective heat exchange is obtained by calculating the product of the single product mass of the target product, the specific heat capacity of the target product material, the difference between the target sintering temperature and the production environment temperature, and the geometric shape factor. The geometric shape factor is calculated from the product surface area and volume. The difference between the actual effective heat power and the implicit attenuation caused by grid fluctuations is taken as the conservative actual heating power. The ratio of the total effective heat exchange to the conservative actual heating power is used as the baseline time for the target product to occupy the heating zone under the current heating conditions.
[0007] Preferably, the geometric morphology factor is a volume normalization process applied to the product surface area based on the principle of geometric similarity.
[0008] Preferably, the basic blocking distance between adjacent products is obtained as follows: Calculate the heat load gradient of adjacent products, determine the global reference time based on the reference time of all products, and calculate the asymmetric impact intensity according to the piecewise function based on the heat load gradient, the global reference time, and a fixed asymmetric coefficient greater than 1. Divide the asymmetric impact intensity by the belt linear velocity to obtain the basic blocking distance.
[0009] Preferably, the total deviation is obtained in the following way: Calculate the difference between the base time and the global base time for each product in the production sequence to obtain the deviation of a single product relative to the global average heat load. Accumulate the deviations of all products from the starting position to the current position in the production sequence to obtain the total deviation caused by the preceding products. The cumulative thermal energy drift rate when scheduling to the current product is obtained by dividing the total deviation caused by the preceding products by the global reference time.
[0010] Preferably, the actual blocking distance is obtained in the following way: Calculate the sum of 1 and the cumulative thermal potential drift rate when scheduling to the current product position. Select the maximum value between the calculation result and the minimum constant as the correction coefficient for the thermal offset state. Based on the correction coefficient, correct the basic hindrance distance to obtain the true hindrance distance between adjacent products.
[0011] Preferably, the objective function is constructed as follows: The total idle distance of the conveyor belt corresponding to the entire sequence is calculated by adding up the actual blocking distances between all adjacent products in the complete production sequence.
[0012] Secondly, a multi-product intelligent scheduling system for powder metallurgy includes a processor and a memory, wherein the memory stores computer program instructions, and when the computer program instructions are executed by the processor, the above-mentioned multi-product intelligent scheduling method for powder metallurgy is implemented.
[0013] The present invention has the following effects: 1. This invention can quantitatively distinguish the differences in instantaneous heat absorption load of various products after they are put into the furnace by calculating the reference time for heating products of different specifications and materials. It overcomes the problem that existing technologies rely on experience-based sorting and cannot quantify the transient thermal shock intensity of individual products. It achieves standardized and refined characterization of the product's thermal load capacity and provides accurate quantitative basis for calculating the thermal shock during the product alternation process.
[0014] 2. This invention introduces a fixed asymmetry coefficient and combines it with piecewise functions to calculate asymmetric impact intensity. This can closely match the asymmetric thermal inertia physical characteristics of sintering furnaces, which are easy to heat up and difficult to cool down. It can differentiate the different impact hazards of two working conditions: sudden increase in heat load and sudden decrease in heat load. Based on the calculation of the basic hindrance distance based on the actual thermal shock intensity, it solves the shortcomings of traditional uniform spacing production and symmetrical production models that cannot adapt to the asymmetric heat transfer characteristics of the furnace body. This makes the product switching interval completely match the actual heat tolerance law of the furnace and greatly reduces the furnace temperature fluctuation caused by product switching.
[0015] 3. This invention obtains the total deviation by accumulating the thermal load deviation of preceding products and normalizes it to obtain the cumulative thermal potential energy drift rate, which can accurately characterize the continuous thermal deficit or thermal redundancy state generated in the furnace during long-batch continuous production. Furthermore, it dynamically corrects the basic hindrance distance through the thermal offset correction coefficient to achieve adaptive compensation for historical cumulative thermal deviation. It overcomes the shortcomings of traditional production scheduling that only considers instantaneous product matching and ignores the cumulative thermal drift of the sequence, and fundamentally solves the problems of continuous furnace temperature instability and large fluctuations in the sintering quality of batch products under long-sequence production conditions. While ensuring uniform and stable sintering quality, it improves the utilization rate and production energy efficiency of the production line by minimizing the total idle distance of the conveyor belt. Attached Figure Description
[0016] Figure 1 This is a flowchart of steps S1-S4 in an intelligent scheduling method for multiple products in powder metallurgy according to an embodiment of the present invention.
[0017] Figure 2 This is a structural block diagram of a multi-product intelligent scheduling system for powder metallurgy according to an embodiment of the present invention. Detailed Implementation
[0018] 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 some embodiments of the present invention, but not all embodiments.
[0019] Reference Figure 1 A method for intelligent scheduling of multiple products in powder metallurgy includes steps S1-S4, as detailed below: S1: Obtain and preprocess production-related data for powder metallurgy sintering. Production-related data includes product unit mass, product specific heat capacity, target sintering temperature, ambient temperature, product surface area and volume, actual effective heat power, and conveyor belt speed.
[0020] Production-related data is divided into: static basic data and dynamic operational data.
[0021] Static basic data is entered once and will not be sampled again during production. Format and numerical rationality checks are added to the static data.
[0022] Product unit mass refers to the mass of a single powder metallurgy product to be sintered. Mass is a core physical parameter that determines the total amount of heat stored and absorbed by the product. The greater the product mass, the more heat it absorbs after entering the furnace, and the stronger the thermal disturbance it causes to the furnace temperature field. It is a basic indicator for calculating the product's heat load.
[0023] The specific heat capacity of a product material is the specific heat capacity of the product's base material, representing the amount of heat absorbed by a unit mass of product to increase its temperature by one unit. Different powder metallurgy materials have different thermophysical properties, and specific heat capacity directly reflects the material's heat absorption capacity. It is used to accurately distinguish the heat absorption characteristics of different products and ensure that heat load calculations accurately reflect the actual properties of the materials.
[0024] Product surface area and product volume are the external surface area and solid volume of a single product, respectively. These two parameters characterize the product's geometry. Combined calculations yield a geometric shape factor, quantifying the impact of the product's external structure on furnace heat exchange efficiency and recreating the actual heat transfer conditions within the furnace.
[0025] The sampling period for dynamic operation data is 1 second. After data acquisition, preprocessing is carried out uniformly: the dynamic operation data and the original weighing signal output by the dynamic checkweigher are filtered out by sliding time window mean filtering to remove noise caused by mechanical vibration and instantaneous impact, and abnormal data exceeding the process threshold are removed; all data are standardized in measurement units and sensor calibration is completed.
[0026] The sintering target temperature is the standard temperature that the product must reach to complete sintering, as specified in the process. This parameter is the core temperature control indicator of the sintering process, and together with the ambient temperature, it determines the total temperature difference required for the product to heat up. The magnitude of the temperature difference directly affects the overall heat absorption of the product.
[0027] The production environment temperature refers to the ambient temperature at the location of the sintering equipment, serving as the initial temperature of the product before it enters the furnace. Combined with the target sintering temperature, the overall temperature rise difference of the product can be calculated, which is a necessary parameter for calculating the total heat absorption of the product.
[0028] True effective thermal power refers to the actual and stable effective heating power that the sintering furnace heating device can output. This parameter reflects the equipment's heating capacity per unit time and is a core equipment parameter for calculating the product heating baseline duration and matching the furnace's heating level.
[0029] The linear speed of the conveyor belt refers to the operating speed of the conveyor belt carrying the products, representing the speed at which the products move within the furnace. This parameter is used to convert the dimensionality between thermal shock intensity and spatial distance, and is a key operating parameter for translating thermal parameters into product layout spacing.
[0030] The aforementioned data encompasses the product's own thermophysical parameters, geometric parameters, process temperature control parameters, and sintering equipment operating parameters, comprehensively covering the fundamental conditions required for the entire process calculation, including heat load, heating time, thermal shock, and layout spacing. Preprocessing the acquired production-related data filters out interference noise generated during on-site data collection, corrects abnormal data, and improves data accuracy and reliability, providing a true and effective data source for subsequent calculations of product baseline time, heat load gradient, hindrance distance, and production scheduling optimization models.
[0031] S2: Calculate the reference time for each product to occupy the heating zone based on the pre-processed production-related data. Calculate the basic resistance distance between adjacent products based on the reference time difference between adjacent products, the global reference time, and the asymmetry coefficient.
[0032] Select any product in the production sequence as the target product, and determine the single-piece mass, material specific heat capacity, temperature difference between the sintering target temperature and the production environment temperature, and geometric morphology factor of the product in sequence. Multiply the four parameters together to obtain the total effective heat exchange heat of the target product.
[0033] The geometric morphology factor is a dimensionless coefficient calculated from the actual surface area and volume of a product, used to characterize the impact of the product's shape and structure on its heat absorption and exchange capacity. Different products have different shapes and sizes, resulting in varying contact areas and heat storage characteristics with the high-temperature medium inside the furnace, directly affecting the overall heat absorption efficiency. Larger surface areas and smaller volumes lead to higher heat contact and transfer efficiency, corresponding to larger geometric morphology factor values. Introducing the geometric morphology factor quantifies the differences in heat exchange caused by product structure, ensuring that the calculated heat values match the actual sintering conditions on site.
[0034] Next, the conservative true heating power of the heating device is calculated: based on the actual effective thermal power of the heating device, the implicit power attenuation caused by power grid fluctuations is subtracted to obtain the conservative true heating power. Industrial power grids are prone to small fluctuations, which can cause abnormal losses in heating power, preventing the equipment from continuously maintaining its rated effective power output. The conservative true heating power obtained after subtraction reflects the effective power that the heating device can stably output in actual production, eliminating the deviation between theoretical calculations and actual heating capacity.
[0035] Finally, the ratio of the previously calculated total effective heat exchange to the conservative actual heating power is used to calculate the baseline time required for the target product to occupy the furnace heating zone under the current heating conditions. This calculation method follows basic thermodynamic laws, dividing the total heat exchanged by the product by the heat that the heating device can stably supply per unit time to obtain the standard heating time of the product. This provides a basic calculation basis for subsequent product scheduling and furnace thermal condition control.
[0036] Specifically, the reference time satisfies the following relationship: ; In the formula, Indicates the first The reference time that a product occupies in the heating zone under the current heating conditions represents the theoretical time equivalent required for the product to complete sintering and exchange. Indicates the first The unit quality of this product Indicates the first The specific heat capacity of the material of this product Indicates the target sintering temperature. Indicates the ambient temperature of the production environment. Denotes the geometric shape factor, where Indicates the product surface area. Indicates product volume. Based on the similarity transformation law of surface area and volume of geometric bodies, this method is used to normalize the surface area of products, converting the absolute surface area into the relative heat transfer area corresponding to a unit equivalent volume. Indicates the true effective thermal power. This indicates the amount of implicit degradation caused by power grid fluctuations.
[0037] A dynamic checkweigher is used to weigh the product in real time. The original weighing signal is then processed by statistical mean filtering through a sliding time window to remove instantaneous mechanical impact noise and extract a mass benchmark that accurately represents the volume of the product's heat storage carrier, ultimately yielding the mass of a single product. The mass of a single product is the core physical quantity that determines the product's heat storage capacity. The amount of heat absorbed by a product is directly proportional to its mass; the greater the mass, the stronger the heat storage capacity, the more heat it absorbs after entering the furnace, and the more significant the heat absorption impact on the furnace temperature field. Therefore, the mass of a single product is the core influencing factor characterizing the product's heat load.
[0038] The materials used in powder metallurgy products have different thermal properties. Specific heat capacity determines the heat absorption capacity per unit mass of the material. Introducing this parameter can accurately distinguish the impact of material differences on the heat absorption process, allowing the heat load calculation to match the actual thermophysical characteristics of different materials. The temperature difference between the target sintering temperature and the production environment temperature determines the total heat absorbed by the product from the ambient temperature to the process temperature. The greater the temperature difference, the higher the heat absorption required by the product, and the stronger the thermal disturbance generated in the furnace.
[0039] The heat exchange intensity of a product is directly related to its surface area. The larger the surface area, the more complete the heat exchange interface between the product and the high-temperature environment of the furnace, the faster the heat absorption rate, and the more severe the transient impact on the furnace temperature. After normalizing the volume, the heat exchange intensity of products with different geometric shapes can be objectively distinguished, so that the heat load calculation conforms to the actual heat transfer law inside the furnace.
[0040] By comprehensively considering product quality, material specific heat capacity, temperature difference during heating, and geometric morphology factors, the total effective heat exchange load and transient thermal shock intensity generated after the product enters the furnace are fully characterized. Simultaneously, by subtracting implicit attenuation from the actual effective heat power, a conservative heating capacity that the heating system can stably output under complex operating conditions is obtained. Based on the dimensional relationship between heat, power, and time, the reference time is calculated by dividing the total heat absorption by the conservative heating power. The physical logic is rigorous, and the calculation results accurately reflect the standard residence time of the product in the heating zone.
[0041] By combining the base time corresponding to each product, the heat load gradient between two adjacent products in the production sequence is calculated; then, based on the base time of all products in the entire batch, the global base time is obtained. Further combining the heat load gradient, the global base time, and a fixed asymmetric coefficient greater than 1, the asymmetric impact intensity is obtained through piecewise function calculation. Finally, the asymmetric impact intensity is divided by the conveyor belt linear velocity to calculate the basic resistance distance between adjacent products.
[0042] The heat load gradient refers to the difference in heat load between two adjacent products in the production sequence. It is used to quantify the abrupt change in furnace heat load when products are switched. The product reference time directly corresponds to its own heat load magnitude. The greater the difference in reference time between adjacent products, the higher the heat load gradient value, indicating a more severe thermal shock to the furnace temperature field caused by the product switching process. It can intuitively characterize the degree of change in the furnace thermal state caused by product replacement and is the core basis for judging the strength of thermal shock.
[0043] The global reference time refers to the statistical average of the reference times of all products in the entire batch, serving as a unified reference for the heat load of the entire batch. It can unify the scale of heat load comparison between different products and combinations, avoid evaluation bias caused by single product parameters, and ensure the consistency and rationality of impact intensity calculation.
[0044] The fixed asymmetry coefficient is a preset constant with a value greater than 1. Example values are 1.2, 1.5, or 1.8. In practical applications, it can be adjusted according to the sintering furnace specifications, product categories, and process temperature ranges. Because the sintering furnace has different tolerances to sudden increases and decreases in heat load, the allowable safety intervals under these two conditions also differ; that is, the thermal shock effect has asymmetric characteristics. This coefficient is set to differentiate and correct the thermal shock intensity in different directions, conforming to the asymmetric operating characteristics of the sintering furnace and ensuring that the calculation results match on-site safety control requirements.
[0045] Asymmetric impact intensity is a quantitative indicator calculated using a piecewise function combined with the aforementioned parameters. It comprehensively reflects the overall thermal shock intensity experienced by the furnace during the switching between adjacent products. The piecewise function distinguishes between two different operating conditions: heat load increase and heat load decrease. Furthermore, the asymmetric coefficient is used to perform differentiated corrections, accurately restoring the true thermal shock level under different switching scenarios.
[0046] Specifically, the asymmetric impact intensity satisfies the following relationship: ; In the formula, Indicates the first The product and the first The asymmetric impact intensity generated when two products are switched sequentially in a mesh belt sintering furnace represents the transient thermal shock intensity caused to the furnace temperature field during the switching process, expressed in units of time. This represents the square of the heat load gradient. This represents a fixed asymmetry coefficient, with a value greater than 1, determined by the ratio of the furnace's natural cooling rate to its electric heating rate, and applies an amplification penalty only to negative heat load gradients. Indicates the first The base time of the product and the first The difference in the base time of each product is... This reflects the heat load gradient. Represents the global reference time, that is This reflects the average of the reference time for all products in the current batch, serving as a global normalization benchmark.
[0047] The basic blocking distance is the initial safety interval that needs to be reserved between adjacent products. Asymmetric impact intensity characterizes the combined effect of thermal shock, and the conveyor belt linear velocity represents the conveying rate of the product in the furnace. The division between the two is based on the kinematic relationship to complete the conversion of physical dimensions, transforming the thermal shock intensity into a spatial distance in the conveyor belt direction, thereby determining the minimum initial interval required to avoid thermal shock and ensure sintering quality.
[0048] S3: Based on the total deviation of the product baseline time in the production schedule, quantify the cumulative thermal energy drift rate, and use the cumulative thermal energy drift rate to correct the basic stall distance to obtain the true stall distance between adjacent products.
[0049] By quantifying the overall thermal offset state accumulated in the furnace during the production scheduling process, the cumulative effect of heat load generated by the continuous arrangement of preceding products can be accurately characterized. First, the difference between the reference time and the global reference time of each product in the production scheduling sequence is calculated one by one to obtain the heat load deviation value of a single product relative to the overall average heat load level.
[0050] The heat load deviation values corresponding to all products in the production sequence from the starting position to the current position are accumulated and summed to obtain the total deviation formed by the combined effect of all preceding products.
[0051] The total deviation is then compared with the global reference time, and after normalization, the cumulative thermal potential drift rate is obtained.
[0052] The heat load deviation is the difference between the reference time for a single product and the global reference time, used to characterize the degree of deviation of the heat load of a single product from the average heat load of the entire batch. When the deviation is positive, it indicates that the product is a high heat-absorbing product, which will consume more heat in the furnace and is prone to causing a heat deficit in the furnace; when the deviation is negative, it indicates that the product is a low heat-absorbing product, which consumes less heat in the furnace and will cause thermal redundancy in the furnace. By calculating the deviation of a single product, the independent disturbance characteristics of each product to the thermal conditions inside the furnace can be accurately distinguished.
[0053] The total deviation is the sum of the heat load deviations of all individual products from the start of production scheduling to the current position. The sintering furnace has significant thermal inertia; the heat absorption effect of multiple preceding products will continuously accumulate and superimpose, affecting the subsequent furnace temperature, rather than the effect of a single product acting independently. By accumulating all preceding deviations, the overall offset effect of the historical production sequence on the current furnace thermal baseline can be fully restored, truly reflecting the real-time thermal imbalance of the furnace.
[0054] The cumulative thermal potential drift rate is a dimensionless state parameter obtained by normalizing the total deviation to the global reference time. It is used to uniformly and quantitatively characterize the degree of cumulative thermal offset in the furnace.
[0055] The total deviation obtained by direct summation has a time dimension, and its numerical scale fluctuates with batch product specifications, lacking horizontal comparability and operational universality. By normalizing by dividing by a global reference time, the influence of numerical scale caused by product specifications and batch differences can be eliminated, and the two offset states of furnace thermal deficit and thermal redundancy can be uniformly mapped to the same evaluation system. The cumulative thermal potential energy drift rate can continuously and dynamically reflect the cumulative drift trend of furnace thermal potential energy during production scheduling, providing a core state basis for the dynamic adaptive correction of subsequent product safety distances.
[0056] Specifically, the total deviation satisfies the following relationship: ; In the formula, Indicates production schedule up to the [number]th Cumulative thermal energy drift rate when the product is in position The first in the production scheduling sequence The base time for each product The numerator represents the average of the baseline times for all products in the entire batch, which is the global baseline time. This is the total deviation between the reference time of all products and the global reference time, starting from the initial point in the sequence. If it is positive, it indicates that a large number of high heat-absorbing products were produced in the preceding sequence, and the furnace is in a state of heat deficit; if it is negative, it is in a state of heat redundancy.
[0057] First, calculate the sum of the numerical value and the cumulative thermal potential drift rate corresponding to the product scheduled up to the current position. Then, select the larger value from the calculated result and the preset minimum constant, and use this as the thermal offset state correction coefficient. Use the thermal offset state correction coefficient to correct the basic hindrance distance between adjacent products, and finally obtain the true hindrance distance between adjacent products.
[0058] The thermal offset state correction coefficient is a correction parameter calculated based on the real-time thermal offset state of the furnace. It is used to dynamically adjust the safety interval between products according to the furnace thermal conditions formed by the preceding products.
[0059] Furnace thermal deficit and thermal redundancy continuously affect the intensity of thermal shock during product switching, and a single basic blocking distance cannot adapt to the dynamically changing furnace conditions. By introducing this correction coefficient, the cumulative thermal offset effect in the furnace can be quantified and applied to the spacing calculation, enabling the safety interval to be adaptively adjusted according to the thermal state inside the furnace, thus balancing process safety and production efficiency.
[0060] The minimum constant is a fixed, small positive number that is set in advance. For example, the minimum constant is set to 0.001, which is the lower limit of the value of the thermal offset state correction coefficient.
[0061] When the furnace is in a state of thermal redundancy for a long period of time, the cumulative thermal potential energy drift rate remains negative, which will cause the aforementioned summation result to continuously decrease. Setting a minimum constant as a threshold constraint can forcibly limit the minimum value of the correction coefficient, preventing the correction coefficient from approaching zero infinitely, preventing the product layout spacing from being excessively compressed, and fundamentally avoiding process risks such as product overheating and furnace temperature runaway caused by insufficient spacing, thus ensuring the stability of production operation.
[0062] The final product spacing, obtained after correcting the actual blocking distance with the thermal offset state correction coefficient, is the actual safety distance that needs to be reserved between adjacent products after comprehensively considering instantaneous thermal shock and cumulative thermal offset in the furnace.
[0063] The basic blocking distance is designed only for the instantaneous thermal shock caused by the switching between adjacent products, without taking into account the long-term cumulative thermal offset effect in the furnace. After a second correction by superimposing the thermal offset state correction coefficient, the resulting true blocking distance takes into account both local instantaneous thermal shock and global cumulative thermal conditions, perfectly matching the complex thermodynamic environment of the sintering furnace during continuous operation, and providing an accurate and reliable spatial basis for product layout.
[0064] Specifically, the actual blocking distance satisfies the following relationship: ; In the formula, Indicates the number of units in the production scheduling sequence Product No. 1 and No. 1 The actual resistance distance that ultimately needs to be maintained between products. Indicates the number of units in the production scheduling sequence Product No. 1 and No. 1 Basic resistance distance between products Indicates production schedule up to the [number]th Cumulative thermal potential drift rate of the product Represents a minimal constant. , This represents the maximum value function.
[0065] By adding 1, the continuously accumulated thermal offset state in the furnace can be converted into an adjustable coefficient. When the furnace is in a thermal deficit state due to a large number of high heat absorption products in the preceding sequence, the added value is greater than 1, which will correspondingly increase the obstruction distance between adjacent products, reserving sufficient heat replenishment space for the furnace and maintaining temperature stability. When the furnace is in a thermal redundancy state, the added value is less than 1, which can reasonably shorten the product interval, optimize the production cycle, and realize the overall thermal condition formed by historical production scheduling, and make dynamic and continuous adaptive adjustments within the product interval.
[0066] By selecting the lowest values of the adjustable coefficient and the limiting correction coefficient, even if the furnace is in a state of thermal redundancy for a long time, it can prevent the correction coefficient from being too small and the blocking distance between adjacent products from being reduced indefinitely. This ensures that the products maintain a reasonable interval, avoids furnace temperature exceeding the standard and sintering quality degradation caused by insufficient spacing, and ensures stable operation of the equipment.
[0067] S4: With the goal of minimizing the sum of all real stall distances in the production scheduling sequence, construct the objective function and solve for the optimal production scheduling sequence. Then, issue the optimal production scheduling sequence for execution and support dynamic rescheduling.
[0068] Traverse the complete product scheduling sequence, extract the actual obstruction distance corresponding to each group of adjacent products in the sequence, and sum all the values to finally obtain the total idle distance of the conveyor belt corresponding to the scheduling sequence.
[0069] The actual resistance distance refers to the mesh belt gap distance that must be reserved between two adjacent products to offset thermal shock, stabilize furnace temperature, and ensure sintering quality. The mesh belt gap distance is an unavoidable non-conveying area in the production process. When the mesh belt passes through this section, there are no products carrying it, and it only runs empty.
[0070] The total idle distance of the conveyor belt refers to the sum of the actual obstruction distances between all adjacent products within a complete production sequence, representing the total length of ineffective operation of the conveyor belt in the entire production process.
[0071] Specifically, the total idle distance of the conveyor belt satisfies the following relationship: ; In the formula, The total idle distance of the conveyor belt represents the complete product production sequence. This indicates the total number of products in the current production sequence. Indicates the number in the production scheduling sequence The product and the first The actual resistance distance of each product This indicates the complete product production sequence.
[0072] The actual idling distance is a necessary interval to prevent over- or under-burning of the product and to adapt to fluctuations in furnace heat load; it is an objectively existing ineffective stroke during the production process. The total idling distance obtained by summing these distances is based entirely on thermodynamic constraints, not on an artificially set abstract indicator, and has a clear physical meaning.
[0073] The thermal shock, furnace temperature fluctuations, and energy consumption losses caused by different product combinations and production sequences are transformed into the same quantifiable index, enabling horizontal comparison of all production sequences. The objective function takes the total idling distance as the optimization object. Idle distance itself is an ineffective stroke in production. Minimizing the total idling distance directly corresponds to the workshop's demand to reduce useless work and improve efficiency. Idle distance is calculated from the furnace temperature thermal conditions. Reducing the idling distance will inevitably make the thermal transition between products smoother, which corresponds to the core needs of stabilizing furnace temperature and ensuring product quality on site. The optimization direction is completely consistent with the goal that the production line wants to achieve.
[0074] It should be noted that the total idling distance is used as the evaluation criterion. The smaller the distance value, the better the thermal adaptability and production efficiency of the production scheduling scheme. The production scheduling sequence with the smallest total idling distance obtained by optimization is the ideal production scheduling scheme that satisfies furnace temperature stability and optimal energy consumption.
[0075] This invention also provides an intelligent scheduling system for multiple products in powder metallurgy. For example... Figure 2 As shown, the system includes a processor and a memory. The memory stores computer program instructions, which, when executed by the processor, implement a multi-product intelligent scheduling method for powder metallurgy according to the first aspect of the present invention. The system also includes other components well known to those skilled in the art, such as a communication bus and a communication interface. Their configuration and functions are known in the art and will not be described further here.
[0076] It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept, and these all fall within the scope of protection of this invention. Therefore, the scope of protection of this patent should be determined by the appended claims.
Claims
1. A method for intelligent scheduling of multiple products in powder metallurgy, characterized in that, include: Acquire and preprocess production-related data for powder metallurgy sintering. The production-related data includes the mass of a single product, the specific heat capacity of the product, the target sintering temperature, the ambient temperature, the surface area and volume of the product, the actual effective heat power, and the mesh belt speed. Based on the preprocessed production-related data, the reference time for each product to occupy the heating zone is calculated. Based on the reference time difference between adjacent products, the global reference time, and the asymmetry coefficient, the basic resistance distance between adjacent products is calculated. Based on the total deviation of the product reference time in the production sequence, the cumulative thermal energy drift rate is quantified, and the basic blocking distance is corrected using the cumulative thermal energy drift rate to obtain the true blocking distance between adjacent products. The objective is to minimize the sum of all actual delay distances in the production scheduling sequence. An objective function is constructed and the optimal production scheduling sequence is solved. The optimal production scheduling sequence is then issued for execution and dynamic rescheduling is supported.
2. The intelligent scheduling method for multiple products in powder metallurgy according to claim 1, characterized in that, The reference time for each product to occupy the heating zone includes: Taking any product as the target product, the total effective heat exchange is obtained by calculating the product of the single product mass of the target product, the specific heat capacity of the target product material, the difference between the target sintering temperature and the production environment temperature, and the geometric shape factor. The geometric shape factor is calculated from the product surface area and volume. The difference between the actual effective heat power and the implicit attenuation caused by grid fluctuations is taken as the conservative actual heating power. The ratio of the total effective heat exchange to the conservative actual heating power is used as the baseline time for the target product to occupy the heating zone under the current heating conditions.
3. The intelligent scheduling method for multiple products in powder metallurgy according to claim 2, characterized in that, The geometric morphology factor is a volume normalization process applied to the surface area of the product based on the principle of geometric similarity.
4. The intelligent scheduling method for multiple products in powder metallurgy according to claim 1, characterized in that, The method for obtaining the basic resistance distance between adjacent products is as follows: Calculate the heat load gradient of adjacent products, determine the global reference time based on the reference time of all products, and calculate the asymmetric impact intensity according to the piecewise function based on the heat load gradient, the global reference time, and a fixed asymmetric coefficient greater than 1. Divide the asymmetric impact intensity by the belt linear velocity to obtain the basic blocking distance.
5. The intelligent scheduling method for multiple products in powder metallurgy according to claim 1, characterized in that, The total deviation is obtained as follows: Calculate the difference between the base time and the global base time for each product in the production sequence to obtain the deviation of a single product relative to the global average heat load. Accumulate the deviations of all products from the starting position to the current position in the production sequence to obtain the total deviation caused by the preceding products. The cumulative thermal energy drift rate when scheduling to the current product is obtained by dividing the total deviation caused by the preceding products by the global reference time.
6. The intelligent scheduling method for multiple products in powder metallurgy according to claim 1, characterized in that, The method for obtaining the actual blocking distance is as follows: Calculate the sum of 1 and the cumulative thermal potential drift rate when scheduling to the current product position. Select the maximum value between the calculation result and the minimum constant as the correction coefficient for the thermal offset state. Based on the correction coefficient, correct the basic hindrance distance to obtain the true hindrance distance between adjacent products.
7. The intelligent scheduling method for multiple products in powder metallurgy according to claim 1, characterized in that, The objective function is constructed as follows: The total idle distance of the conveyor belt corresponding to the entire sequence is calculated by adding up the actual blocking distances between all adjacent products in the complete production sequence.
8. A multi-product intelligent scheduling system for powder metallurgy, characterized in that, include: A processor and a memory, wherein the memory stores computer program instructions that, when executed by the processor, implement the intelligent scheduling method for multi-product powder metallurgy as described in any one of claims 1-7.