A method and system for managing a ferrostatic sand casting process

Abstract

The application relates to the technical field of casting process management, and discloses an iron-type sand-coating casting process management method and system, which has the technical scheme as follows: the measured temperatures and heat absorption and heat dissipation histories of multiple regions of an iron type are acquired, residual heat deviation is determined, and a dynamic temperature upper limit is calculated, so that sand coating is prevented from being started when local temperature exceeds the standard, the problem that the prior art cannot identify local heat accumulation and causes unstable sand coating quality is solved, and the method has the advantages of improving the accuracy of judgment of sand coating process starting conditions, preventing sand coating defects caused by local high temperature, and improving the stability of casting process quality.

Description

Technical Field

[0001] This application relates to the field of casting process management technology, and more specifically, to a method and system for managing the sand-coated casting process in iron molds. Background Technology

[0002] In the sand-coated casting process, the mold needs to be recycled across multiple production cycles. Before each cycle begins, the mold is typically cleaned and its temperature checked to ensure it has cooled sufficiently and is in a suitable initial state for sand coating. A uniform layer of molding sand is then applied to the mold surface using a sand-shooting device. Following this, the mold is closed, poured, cooled, and then opened. After the high-temperature pouring of the previous cycle, the mold body, especially in areas corresponding to thicker or hotter parts of the casting, accumulates significant heat due to its larger heat capacity and longer heat dissipation path. Under continuous short-cycle production conditions and compressed cooling time, even if the overall average temperature of the mold falls back to what is generally considered a safe range, the temperature in these localized areas may still be significantly higher, forming localized high-heat zones. With each cycle, this regional temperature difference caused by the heat accumulation from previous cycles gradually intensifies, resulting in significant differentiation in the actual thermal state of different areas of the mold before sand coating.

[0003] like Figure 4 As shown, most conventional process management methods currently rely on uniform temperature thresholds or fixed cooling times to determine whether a mold is ready for the sand coating process. For example, single-point temperature measurement is performed at a fixed location on the mold, or the average value of several measuring points on the surface is taken. When the measured temperature is lower than the preset overall limit, or when the set cooling time has been reached since the last mold opening, the entire mold is considered ready for sand coating. This type of method essentially simplifies the mold into a uniformly heated object, failing to distinguish the temperature non-uniformity caused by structural differences and varying heating histories in different areas.

[0004] In actual continuous production, because a uniform benchmark cannot reflect the true thermal state of local high-heat areas, situations often arise such as... Figure 4 The diagram illustrates a situation where the overall temperature meets the release criteria, but the surface temperature in certain areas far exceeds the allowable upper limit for the sand coating process. If sand coating is initiated prematurely under these conditions, the excessively high local interface temperature will alter the solidification rate, adhesion strength, and thickness distribution of the molding sand in that area, easily leading to defects such as poor sand coating bonding or abnormal local thickness. These problems may further cause defects such as mold closing gap deviations, pouring runaway, or porosity and sand adhesion in the casting during subsequent mold closing and pouring processes, directly affecting casting quality and process stability. In on-site management, the resulting uneven sand coating or casting defects are often attributed to fluctuations in the sand-shooting equipment or occasional process abnormalities, making it difficult to trace back to the source of the problem: inaccurate judgment of the initial conditions before sand coating.

[0005] It is evident that existing technologies lack effective means to identify and address temperature differences in different areas of the iron mold caused by heat accumulation during multiple processes in the iron mold sand casting process. This results in regional deviations in the initial conditions of the sand coating process, affecting the stability of the sand coating quality and the reliable continuation of subsequent processes.

[0006] To address the aforementioned issues, existing technologies urgently need improvement. Summary of the Invention

[0007] The purpose of this application is to provide a method and system for managing the iron mold sand-coated casting process, which has the advantages of improving the accuracy of judging the start conditions of the sand-coating process, preventing sand-coating defects caused by local high temperature, and improving the quality stability of the casting process.

[0008] This application provides a method for managing the iron mold sand-coated casting process, including: Obtain measured temperature information of multiple areas on the iron mold before sand coating in the current process, as well as historical information on the heating and heat dissipation of multiple areas in previous processes; Based on historical information on heat absorption and dissipation, determine the residual heat deviation of each region at the current moment due to heat accumulation from previous processes. Based on the residual heat deviation, determine the upper limit of the allowable sand covering temperature for each area in the current work cycle; The measured temperature information of each area is compared with the corresponding upper temperature limit. When the measured temperature information of an area is higher than the corresponding upper temperature limit, a control command is generated to prevent the sand covering process from starting.

[0009] Furthermore, the multiple regions are obtained by meshing the iron mold surface into multiple thermal management grids; In multiple thermal management grids, grids applied to thick or hot spots in castings are marked as high-risk areas for hot spots. Obtain measured temperature information for multiple regions on the mold before sand coating in the current process, including: obtaining the surface temperature corresponding to each thermal management grid.

[0010] Furthermore, the heating and cooling history information includes the initial temperature of each grid at the end of each pouring in the most recent N preceding pouring cycles and the first duration from the end of that pouring cycle to the current moment; The steps to determine the residual heat deviation of each region at the current moment due to heat accumulation from previous processes include: Obtain a thermal response reference relationship to characterize the temperature decay over time after a single pouring; For each grid, based on the starting temperature and first duration of each of the last N operations, the residual influence component of that operation at the current moment is determined using the thermal response reference relationship. The residual influence components of the most recent N cycles are weighted and superimposed to generate the residual heat deviation of the grid at the current moment.

[0011] Furthermore, based on the residual heat deviation, the upper limit of the allowable sand covering temperature for each area in the current work cycle is determined, including: For each grid, obtain a reference temperature upper limit to characterize the highest allowable sand covering temperature for that grid without prior heat accumulation; Subtracting the residual heat deviation of the grid from the reference temperature upper limit yields the upper limit of the allowable sand covering temperature for the grid in the current operation.

[0012] Furthermore, the steps for comparing the measured temperature information of each region with the corresponding upper temperature limit include: For each region, calculate the difference between the measured temperature information and the upper temperature limit; When the difference is less than or equal to a preset first threshold, the area is marked as a state where sand can be covered normally. The first threshold is not greater than zero. When the difference is greater than the first threshold and less than or equal to the preset second threshold, the area is marked as a state that needs to be processed. The second threshold is greater than zero. When the difference is greater than the second threshold, the area is marked as unsuitable for sand covering.

[0013] Furthermore, the steps for generating control instructions to prevent the sand coating process from starting include: Obtain the preset weights corresponding to each region. Areas marked as high-risk hotspots have a higher default weight than other areas; In response to the existence of areas marked as unsuitable for sand covering, a control command is generated to prevent the sand covering process from starting. In response to areas where there are no areas that cannot be covered by sand and areas that are marked as needing to be processed, a weighted score is calculated based on the preset weights and differences of the areas in each needing-to-be-processed state. When the weighted score is lower than the preset allowable delay threshold, a control command is generated to allow the sand covering process to start. When the weighted score is not lower than the preset allowable delay threshold, a program delay control instruction is generated. The program delay control instruction is used to trigger a local cooling operation when the steering conditions are met.

[0014] Furthermore, after the localized cooling operation is performed, it also includes: Acquire temperature values ​​of the area targeted by the local cooling operation at at least two different time points after the local cooling operation is completed, as well as the time points corresponding to each temperature value; Based on at least two temperature values, time points, and the upper limit of the temperature corresponding to the region, determine whether the region meets the preset stable recovery conditions. The stable recovery conditions are used to indicate that the internal heat of the region has been fully dissipated after the local cooling operation rather than just the surface being temporarily cooled. Before a region is determined to meet the conditions for stable recovery, it is prohibited to use the region's temperature information to generate control commands that allow the sand covering process to start.

[0015] Furthermore, at least two temperature values ​​include a first temperature value and a second temperature value in chronological order of acquisition time, and time points include corresponding first time points and second time points, with the second time point being later than the first time point; Determine whether the region meets the preset stable recovery conditions, including: The difference between the upper temperature limit and the first temperature value is calculated as the remaining margin; The difference between the second temperature value and the first temperature value is calculated as the reheat change. When the remaining margin is greater than or equal to the preset stable release margin and the heat return change is less than or equal to the preset heat return limit, the region is determined to meet the stable recovery condition. When the remaining margin is less than zero, the region is determined to be not in a stable recovery condition; When the remaining margin is greater than or equal to zero and the amount of heat return is greater than the preset heat return limit, the judgment area does not meet the stable recovery condition. When the remaining margin is greater than or equal to zero and less than the preset stable release margin, and the amount of heat return change is less than or equal to the preset heat return limit, the third temperature value of the area is obtained after a preset delay. If the third temperature value is less than or equal to the second temperature value, it is determined that the stable recovery condition is met. If the third temperature value is greater than the second temperature value, it is determined that the stable recovery condition is not met. If the same area has undergone two local cooling operations in the current cycle, and the stable recovery conditions are not met after each local cooling operation, no more local cooling operations will be performed on that area, and a control command will be generated to prevent the sand covering process from starting.

[0016] Furthermore, after the current work is completed, it also includes: The surface temperature of each grid in the iron mold before the next sand coating is obtained as feedback temperature information; The time elapsed from the end of the current pouring cycle to the acquisition and feedback of temperature information is used as the calibration duration information; The thermal response reference relationship is corrected based on the initial temperature, feedback temperature, and calibration duration information of each grid at the end of the current pouring cycle. The revised thermal response reference relationship is used to determine the residual heat deviation in subsequent cycles.

[0017] A process management system for iron mold sand-coated casting, used to execute the above-mentioned iron mold sand-coated casting process management method, includes: The information acquisition module is used to acquire the measured temperature information of multiple areas on the iron mold before the current sand coating process, as well as the historical information of the heating and heat dissipation of multiple areas in the previous multiple processes. The residual deviation determination module is used to determine the residual heat deviation of each area at the current moment due to the heat accumulation of the previous process, based on the heating and heat dissipation history information. The threshold determination module is used to determine the upper limit of the allowable sand covering temperature for each area in the current work cycle based on the residual heat deviation. The comparison control module is used to compare the measured temperature information of each area with the corresponding upper temperature limit. When the measured temperature information of an area is higher than the corresponding upper temperature limit, a control command is generated to prevent the sand covering process from starting.

[0018] The beneficial effects of this application are: This application provides a method and system for managing the sand coating casting process in iron molds. By acquiring the measured temperature and heat dissipation history of multiple areas of the iron mold, the residual heat deviation is determined and the dynamic temperature upper limit is calculated. This prevents the sand coating process from starting when the local temperature exceeds the limit, solving the problem that the existing technology cannot identify local heat accumulation, which leads to unstable sand coating quality. It has the advantages of improving the accuracy of judging the starting conditions of the sand coating process, preventing sand coating defects caused by local high temperature, and improving the quality stability of the casting process. Attached Figure Description

[0019] Figure 1 This is a schematic flowchart of the temperature control method for iron mold sand casting process provided in the embodiments of this application.

[0020] Figure 2 This is a schematic diagram of the workflow for managing the iron mold sand-coated casting process provided in the embodiments of this application.

[0021] Figure 3 This is a schematic diagram showing the spatial mapping between the location of the hot spot in the casting and the thermal management grid of the mold, provided in an embodiment of this application.

[0022] Figure 4 This is a diagram illustrating the problems with existing technologies. Detailed Implementation

[0023] The following description, in conjunction with the technical solution of this application, provides a clearer and more complete explanation of the relevant content. It should be noted that the embodiments described herein are only a part of the implementation methods of this application, and not all of them. Other implementation methods obtained by those skilled in the art based on the embodiments of this application without creative effort should also fall within the protection scope of this application. Furthermore, in the description of this application, the terms "first," "second," etc., are mainly for distinction and should not be construed as indicating relative importance.

[0024] Reference Figure 1 This application proposes a method for managing the iron mold sand casting process, including: S1. Obtain the measured temperature information of multiple areas on the iron mold before the current sand coating process, as well as the historical information of the heating and heat dissipation of multiple areas in the previous multiple processes.

[0025] S2. Based on the historical information of heat absorption and dissipation, determine the residual heat deviation of each region at the current moment due to the heat accumulation of previous processes.

[0026] S3. Based on the residual heat deviation, determine the upper limit of the allowable sand covering temperature for each area in the current work cycle.

[0027] S4. Compare the measured temperature information of each area with the corresponding upper temperature limit. When the measured temperature information of an area is higher than the corresponding upper temperature limit, generate a control command to prevent the sand covering process from starting.

[0028] In the continuous, short-cycle production scenario of sand casting using iron molds, the iron mold is reused multiple times. Each cycle involves sand coating, mold closing, pouring, cooling, and mold opening. During pouring, the iron mold is subjected to severe thermal shock from the high-temperature molten iron. Ideally, after completing a cycle and undergoing sufficient cooling, the overall temperature of the iron mold should return to a low temperature suitable for the next sand coating cycle. However, under tight production cycles, areas of the iron mold corresponding to thick or hot parts of the casting, due to their large thickness and high heat capacity, cannot dissipate heat as quickly as other parts of the iron mold. As the cycle progresses, heat gradually accumulates in these areas, forming localized high-heat zones.

[0029] At this point, if a uniform, fixed temperature threshold is still used to determine whether the entire mold meets the sand coating conditions, a disconnect will arise between the judgment criteria and the actual thermal state of the area. The overall macroscopic temperature of the mold may have fallen back to the allowable range, but the actual temperature of the local high-temperature areas may still be significantly higher. If this state of overall compliance with standards but local overheating is allowed, regional deviations will occur at the starting point of the sand coating process. The molding sand in this area will solidify abnormally and its adhesion strength will decrease, potentially leading to uneven mold closing gaps or even casting failure. To address this, this application divides the mold into multiple local units during the sand coating preparation stage, distinguishing between areas corresponding to hot spots and ordinary areas, and collects and judges the thermal state of each unit separately. This shifts the release control from the overall macroscopic indicators of the mold to the independent recovery state verification of each key area.

[0030] For step S1, two types of information are acquired. The first type is the measured temperature information of multiple areas on the mold before the current sand coating process. These areas are pre-divided according to the geometric features of the mold surface and the casting structure, at least distinguishing the high-risk areas of hot spots corresponding to thick parts and hot spots of the casting, as well as ordinary areas used as reference. The division method can be to discretize the mold surface into multiple thermal management grids, assigning a unique identifier to each grid and recording its location and thickness characteristics. When collecting measured temperature information, it can be obtained through an array of temperature sensors placed at key grid positions on the mold surface, or through a non-contact infrared thermal imaging acquisition device to obtain the temperature distribution of the entire mold surface, and then extracting the temperature value corresponding to each grid according to its grid affiliation. The collected temperature information is accompanied by a collection timestamp, forming a snapshot of the area temperature before the current sand coating process.

[0031] The second category is the historical information on the heating and cooling of multiple areas in previous processes. This historical information records the heat input and cooling processes experienced by each area of ​​the mold in the most recent completed processes. The heating and cooling history information includes the initial temperature at the time of casting, the end time of casting, the mold opening time, the release time before sand covering, the actual cooling time experienced in that process, and whether that process is a special process marker indicating whether production was resumed after a shutdown. This information can be extracted from the time node records of the production execution system and historical sensor data, and stored in a structured manner according to the mold number and process sequence number. When extracting historical information, the records of the most recent N processes are selected. The value of N is related to the heat dissipation characteristics of the mold material, and usually covers the main temperature accumulation period of the local high-heat area, for example, 3 to 5 processes.

[0032] For step S2, the residual heat deviation of each region due to heat accumulation in the previous process at the current moment is determined. The purpose is to quantify the additional heat remaining in the corresponding region at the current moment after the thermal shock of the previous process has undergone its respective heat dissipation time. The residual heat deviation here reflects the degree of heat accumulation in the region compared to after only experiencing ideal heat dissipation in a single process, rather than the current absolute temperature value of the region.

[0033] When determining the residual heat deviation, a thermal response reference relationship is first established or obtained. This reference relationship describes the basic law of temperature decay over time after a single heating of the mold material. A single-cycle decay reference model can be established based on parameters such as the heat dissipation coefficient of the mold, ambient temperature, and the heat capacity corresponding to the local thickness of the area, or a typical temperature decay curve can be obtained by fitting historical data. Then, for each area, each historical record of the most recent N cycles is traversed, and the initial temperature at the end of the casting of that cycle and the total duration from the end of the casting of that cycle to the current moment are extracted. The residual influence component of that historical cycle at the current moment is calculated using the thermal response reference relationship. The calculation of the total duration needs to consider possible downtime and cycle time changes between cycles, rather than simply extrapolating based on a fixed cycle interval. Finally, the residual influence components of the most recent N cycles are weighted and superimposed, with the cycle closer to the current cycle having a higher weight, to obtain the residual heat deviation of the area at the current moment.

[0034] For step S3, determine the upper limit of the allowable sand coating temperature for each region in the current cycle. This upper limit is not a uniform value, but a dynamically adjusted result based on the residual heat deviation of the region itself. A reference upper limit can be obtained first. This reference upper limit is the highest allowable sand coating temperature for the region under the premise of no heat accumulation from previous cycles, determined experimentally based on the interface temperature requirement for normal sand adhesion, curing, and the formation of a standard thickness. The reference upper limit may differ for different regions. High-risk areas may have a lower reference upper limit than ordinary areas due to differences in sand thickness or curing time requirements. Then, subtract the residual heat deviation of the region from the reference upper limit to obtain the upper limit of the allowable sand coating temperature for that region in the current cycle.

[0035] This subtractive approach means that the more residual heat a region accumulates in previous cycles, the lower its allowable temperature limit will be for the current cycle. Even if the current measured temperature of a region doesn't appear high, if there is a significant amount of historical heat accumulation, the dynamic release threshold will be pre-set to be more stringent, thus compensating for the potential impact of historical heat accumulation on the quality of the sand-covered interface. Therefore, the actual release condition for each region is no longer simply a surface temperature below a fixed value, but rather a surface temperature below a corrected upper limit that has already accounted for historical heat load.

[0036] For step S4, the measured temperature information of each area is compared with the corresponding upper temperature limit, and a control command for the sand coating process is generated based on the comparison result. The comparison can be performed one area at a time. When the measured temperature of all areas is not higher than their respective upper temperature limits, it indicates that the basic release conditions of each key area of ​​the mold have been met, and a control command to allow the sand coating process to start can be generated at this time.

[0037] When the measured temperature of an area is higher than its corresponding upper temperature limit, it indicates that the area has not fully met the basic release conditions. An initial control command is generated to prevent the sand coating process from starting immediately, so as to avoid the sand coating equipment from directly executing the sand spraying action without confirming the degree of abnormality.

[0038] It should be noted that the initial control command does not necessarily mean that the current operation is finally terminated. In some implementations, the system can further generate subsequent control branches based on the degree of deviation of the out-of-limit area, the risk level of the area, and the recoverability status, such as continuing to wait, local cooling, manual confirmation, or allowing start after meeting preset conditions.

[0039] In other words, the temperature upper limit comparison in this application is first used to identify whether a region deviates from the basic release conditions; for those that do not deviate, they can be released directly; for those that deviate, different control methods can be adopted according to the specific degree of deviation, such as direct blocking, delayed processing, local cooling processing, or release after risk aggregation judgment. In this way, the actual starting point of the sand coating process is no longer determined by a unified overall index, but is jointly constrained by the thermal recovery state of each region and the degree of deviation, so that local high-heat areas are not masked by overall release, and at the same time, unnecessary interruptions to the production cycle due to slight recoverable deviations are avoided.

[0040] In continuous short-cycle production of sand-coated casting, the thermal state of different parts of the mold varies significantly, and localized high-heat zones easily form in areas corresponding to thicker or hotter parts of the casting. If all areas are treated the same, and a uniform temperature benchmark or the average temperature of the entire mold is used to determine whether sand coating is permissible, it is difficult to identify the true thermal state of these localized high-heat zones. Therefore, this application proposes a scheme for dividing and marking the surface of the mold into distinct regions.

[0041] Furthermore, multiple regions are obtained by dividing the surface of the iron mold into multiple thermal management grids; among the multiple thermal management grids, the grids applied to the thick parts or hot spots of the casting are marked as high-risk hot spot areas; the measured temperature information of multiple regions on the iron mold before the current sand coating process is obtained, including: obtaining the surface temperature corresponding to each thermal management grid.

[0042] Specifically, before the sand coating preparation stage begins, a three-dimensional model of the casting and mold flow analysis results can be obtained in advance. (Refer to...) Figure 3It demonstrates the spatial mapping and marking process from the 3D model of the casting and the results of mold flow analysis to the mesh generation of the iron mold surface. Figure 3 The left side of the image shows a 3D model of the casting, with prominent shading or color markings indicating thicker areas—the hot spots identified through mold flow analysis. The right side shows an unfolded 2D mold surface, divided into multiple thermal management grids with independent spatial boundaries by crisscrossing lines. Each grid is labeled with a unique numerical identifier. During the grid division process, the hot spots on the left side of the casting were mapped to corresponding areas on the mold surface based on spatial mapping relationships.

[0043] In this design, several thermal management grids corresponding to the hot spots on the left side of the casting are filled with dark colors or marked with warning patterns. These grids are designated as high-risk areas for hot spots, while the remaining unfilled thermal management grids are marked as ordinary areas. This spatial mapping-based division and marking method allows physical hot spot information to be directly embedded into the area management structure, enabling subsequent processing to clearly distinguish between critical and general areas.

[0044] When acquiring temperature information, an array of temperature sensors or a non-contact infrared thermal imaging acquisition device can be deployed on the surface of the mold to collect the corresponding surface temperature one by one according to the thermal management grid number. The collected temperature data is organized according to the grid number to form a regional temperature distribution table before the current sand covering process. In this distribution table, each thermal management grid records the current surface temperature value and the acquisition timestamp, and also carries an attribute label indicating whether the grid is a high-risk area of ​​the thermal section. In this way, the regional information of the mold surface is transformed from an unstructured state to a gridded and structured state carrying risk attributes, and the temperature acquisition results correspond one-to-one with specific grids.

[0045] The aforementioned grid division and labeling provide definite spatial units for subsequent independent quantification of residual heat deviation for each grid, enabling precise targeting of specific regions in heat accumulation assessment. Simultaneously, distinguishing between high-risk and normal areas of thermal hotspots facilitates stricter admission criteria for high-risk areas in subsequent dynamic threshold determination and status assessment, preventing the averaging or neglect of locally high-heat zones during the assessment. In practical applications, the number and shape of the thermal management grid can be adjusted according to the structure of different castings, and the distribution of high-risk areas of thermal hotspots will also change accordingly with variations in casting structure, thus ensuring that the area division method can adapt to the management needs of different mold structures.

[0046] Furthermore, in some preferred methods, the heating and dissipation history information includes the initial temperature of each grid at the end of each pouring operation in the most recent N preceding operations and the first duration from the end of that pouring operation to the current moment; the step of determining the residual heat deviation of each region at the current moment due to heat accumulation in the preceding operations includes: obtaining a thermal response reference relationship to characterize the temperature decay relationship over time after heating in a single pouring operation; for each grid, based on the initial temperature and first duration of each of the most recent N operations for that grid, using the thermal response reference relationship to determine the residual influence component of that operation at the current moment; and weighting and superimposing the residual influence components of the most recent N operations to generate the residual heat deviation of that grid at the current moment.

[0047] Under continuous short-cycle production conditions, the cooling and heat dissipation time of the mold after the high-temperature pouring of the previous cycle is easily compressed. At this time, it is often difficult for the mold to achieve uniform heat dissipation throughout the cycle, and localized high-heat zones easily form in thicker parts or hot spots of the casting. If the heat dissipation of a single cycle or a simple fixed temperature rise is used to assess the current thermal state, it is difficult to accurately reflect this localized initial state drift caused by the accumulation of heat from multiple consecutive cycles. To address this, this application proposes an estimation based on the superposition of residual heat from the most recent N cycles to quantify the residual heat deviation of each grid at the current moment.

[0048] Specifically, the historical information on heating and dissipation is further refined into the initial temperature at the end of each of the last N preceding pouring cycles for each grid, and the first duration from the end of that pouring cycle to the current moment. The initial temperature can be a temperature snapshot recorded by the corresponding grid sensor at the end of that historical pouring cycle, or an equivalent pouring end temperature obtained by collecting data within a preset sampling delay after pouring and then time-correcting. The first duration can be calculated by the difference between the pouring end timestamp recorded by the industrial control system and the current timestamp; when using the equivalent pouring end temperature, the first duration is consistent with the time reference corresponding to that equivalent initial temperature. The value of N can be determined based on the thermal inertia of the iron mold material and typical heat dissipation curves; for example, it is typically taken as 3 to 5 cycles to cover the main accumulation period of the local high-heat zone. The historical information is limited to the initial temperature and the first duration because these two parameters can be directly used as the initial boundary conditions and time span input for subsequent temperature decay calculations, thus providing the necessary physical calculation basis for quantifying heat accumulation.

[0049] When determining the residual heat deviation, a thermal response reference relationship is first obtained to characterize the temperature decay over time after a single pouring. This thermal response reference relationship can be established based on physical parameters such as the heat dissipation coefficient of the mold material, ambient temperature, mesh thickness, and heat capacity. For example, an exponential decay model can be used to describe the temperature decrease over time of a mesh under standard cooling conditions after a single pouring. It is worth noting that any function, curve, or data table that can characterize the temperature decay over time after a single pouring can be used as this thermal response reference relationship. The purpose of introducing this reference relationship is to provide a physically meaningful baseline decay trajectory for subsequent calculations, so that the estimation of historical thermal effects can fit the heat dissipation law of the mold and avoid remaining at the level of simple empirical estimation.

[0050] Taking a grid in a high-risk area of ​​a thermal event as an example, suppose we need to refer to data from the last three historical cycles. The starting temperature of this grid in the third-to-last cycle was 200 degrees Celsius, 15 minutes ago; the starting temperature in the second-to-last cycle was 210 degrees Celsius, 10 minutes ago; and the starting temperature in the last cycle was 215 degrees Celsius, 5 minutes ago. Substituting these three sets of data into the thermal response reference relationship of this grid, we calculate their residual temperature impact values ​​at the current moment as 2 degrees Celsius, 5 degrees Celsius, and 10 degrees Celsius, respectively. Then, using a linearly decreasing weighting strategy, we assign the last cycle the highest weight of 0.5, the second-to-last cycle a weight of 0.3, and the third-to-last cycle a weight of 0.2. Multiplying each residual impact component by its corresponding weight and summing them, i.e., 2 multiplied by 0.2 plus 5 multiplied by 0.3 plus 10 multiplied by 0.5, we obtain the residual heat deviation of this grid at the current moment as 6.9 degrees Celsius. This value intuitively quantifies the additional heat accumulation caused by the previous three pours at the current moment.

[0051] This deviation value represents the residual temperature of the grid relative to the ideal recovery state after a single heat dissipation cycle, due to heat accumulation from previous cycles. By weighted superposition, the different degrees of influence of recent and future cycles on the current thermal state can be effectively distinguished, making the final deviation value more consistent with the heat accumulation effect in actual production.

[0052] In continuous, short-cycle iron mold sand casting production, although the residual heat deviation of each grid due to historical heat accumulation has been quantified through previous steps, simply knowing this deviation value is not enough to directly control the start-up of the sand coating equipment. The sand coating equipment requires a clear temperature threshold that can be directly compared with the current measured surface temperature. If a uniform, fixed temperature benchmark is still used, the differences in heat accumulation between different grids cannot be reflected, resulting in the deviation information not being effectively translated into sand coating threshold control. Therefore, it is necessary to transform the residual heat deviation into a quantitative standard that can dynamically reflect the impact of historical heat accumulation.

[0053] Furthermore, based on the residual heat deviation, the upper limit of the allowable sand covering temperature for each region in the current process is determined, including: for each grid, obtaining a reference upper limit of temperature to characterize the highest allowable sand covering temperature of the grid when there is no heat accumulation in the previous process; subtracting the residual heat deviation of the grid from the reference upper limit of temperature to obtain the upper limit of the allowable sand covering temperature of the grid in the current process.

[0054] The upper limit of the reference temperature can be understood as the highest interface temperature at which the molding sand can normally adhere, solidify, and form a standard thickness under ideal heat dissipation conditions—that is, when the mold has been fully cooled and there is no residual heat from previous processes. This value can be predetermined through molding sand solidification experiments or historical production data. Considering the differences in physical properties of different areas on the mold surface, the upper limit of the reference temperature can be set separately according to area type. For example, for high-risk areas such as thick parts of the casting or hot spots, which are more sensitive to temperature fluctuations and may have different requirements for the thickness of the coating sand layer, a relatively low upper limit of the reference temperature can be set. For ordinary areas, a relatively high upper limit of the reference temperature can be set. These upper limits of the reference temperature can be pre-stored in the process parameter configuration table and directly read during each process determination.

[0055] After obtaining the upper limit of the reference temperature for each grid, the residual heat deviation calculated in the previous steps is subtracted from the upper limit of the reference temperature using a subtraction operation. Specifically, for any grid, the formula for calculating the upper limit of the allowable sand covering temperature for the current cycle is: The maximum allowable temperature for sand covering in the current work is equal to the maximum reference temperature minus the residual heat deviation.

[0056] This subtraction operation establishes a direct causal relationship: the more severe the heat accumulation in the previous process, the greater the deviation in the calculated residual heat, and the lower the upper limit of the allowable sand covering temperature for the current process obtained after subtraction.

[0057] The reason for using subtraction is that in the iron mold sand coating process, the residual heat deviation represents the correction amount after converting the residual heat effect of the previous process to the temperature dimension in the control calculation, rather than the heat value directly involved in the energy conservation calculation. This correction amount is used to characterize the degree to which the sand coating release conditions need to be tightened further due to the historical heat accumulation inside the region under the same measured surface temperature conditions. In order to ensure that the actual interface thermal state during sand coating does not exceed the process allowable range, this equivalent temperature correction amount needs to be subtracted in advance from the static reference temperature upper limit. Subtraction can intuitively achieve this thermal state compensation, making the calculation process clear and easy to execute quickly in the industrial control terminal, helping to avoid the calculation delay caused by complex models.

[0058] In actual calculations, if a grid experiences a large residual heat deviation due to extremely tight cycles across multiple operations, the resulting upper temperature limit after subtraction might be too low or even negative. To avoid such extreme values ​​causing control logic confusion, a minimum allowable lower temperature limit can be set. When the result of the subtraction operation falls below this minimum allowable lower temperature limit, the allowable upper temperature limit for the current operation is directly truncated to this minimum allowable lower temperature limit. This minimum allowable lower temperature limit can be determined based on the process safety baseline, helping to keep the upper temperature limit within a physically meaningful and reasonable range.

[0059] Through the aforementioned subtraction operation, the upper limit of the allowable sand coating temperature for each grid in the current cycle changes from a fixed static value to a dynamic value that adjusts in real time according to the historical heat accumulation of that grid. This state change refines the management object from a unified standard for the entire mold to the actual thermal state of each key area. For locally hot areas, the dynamic temperature upper limit will be lowered accordingly, requiring that the measured surface temperature of that area be even lower to obtain sand coating approval. This helps to identify and control locally hot areas in a targeted manner during the sand coating preparation stage, preventing them from being incorrectly allowed by the unified static benchmark, thereby reducing problems such as uneven sand coating or subsequent mold closing gaps caused by inconsistent initial states at the source.

[0060] After obtaining the measured temperature information and corresponding dynamic release thresholds for each region, if only a simple comparison method of stopping if the limit is exceeded is still used within the dynamic threshold system, it will be impossible to effectively distinguish between slight deviations and severe deviations, resulting in a lack of specificity in sand cover access control. Therefore, this application further proposes a refined scheme for the comparison steps.

[0061] It should be noted that the aforementioned comparison based on the upper temperature limit can serve as the basic judgment mechanism for sand coating access. In the basic judgment, if the measured temperature is higher than the upper temperature limit, it indicates that the area does not meet the conditions for direct release. Therefore, the system should at least prevent the sand coating process from starting directly without processing at the current moment. Furthermore, to adapt to the actual situation of slight and severe temperature deviations coexisting in continuous short-cycle production, this application can also introduce a graded processing mechanism after the basic judgment. This graded processing mechanism does not negate the constraint effect of the upper temperature limit, but after identifying that the area deviates from the upper temperature limit, it further determines whether the deviation is a slight deviation that can be handled by short-term waiting, local cooling, or risk aggregation, or a severe deviation that should directly prevent the current cycle from starting.

[0062] Therefore, when the measured temperature in a region exceeds the corresponding upper temperature limit, the system can first enter the anomaly handling branch instead of directly making a single final termination conclusion. The anomaly handling branch can include: classifying and marking the degree of deviation, calculating an aggregate score based on the region's risk weight, generating process delay control instructions, triggering local cooling operations, or generating a controlled release instruction when the degree of deviation meets preset acceptable conditions. The results of the above-mentioned classification and processing can serve as the basis for generating the final sand covering control instruction.

[0063] Specifically, the steps for comparing the measured temperature information of each region with the corresponding upper temperature limit include: for each region, calculating the difference between the measured temperature information and the upper temperature limit; when the difference is less than or equal to a preset first threshold, marking the region as a normal sand covering state, with the first threshold not greater than zero; when the difference is greater than the first threshold and less than or equal to a preset second threshold, marking the region as a state requiring processing, with the second threshold greater than zero; when the difference is greater than the second threshold, marking the region as a state where sand covering is not allowed.

[0064] After obtaining the current measured temperature of each region and the dynamic release threshold calculated in the previous steps, it is first necessary to determine the specific degree to which each region deviates from the allowable range. To this end, for each thermal management grid on the iron mold surface, the difference between the measured temperature information and the upper temperature limit is calculated. This difference directly reflects how much space the current grid surface temperature is still away from the maximum allowable sand coating temperature, or how much it has already exceeded.

[0065] The reason this application introduces a first threshold and a second threshold to divide the three intervals is that in continuous short-cycle actual production, fluctuations in the thermal state of local areas of the mold are common. If only a single acceptable threshold is set, immediately stopping the entire mold from being coated with sand if the temperature is even slightly higher, it will frequently interrupt the production rhythm and place a huge burden on on-site operations. On the other hand, if all cases exceeding the acceptable threshold are allowed to pass without distinction, areas with severe heat accumulation will enter the sand coating process with hidden dangers, ultimately leading to defects such as porosity or sand adhesion in the casting.

[0066] Therefore, by setting a first threshold and a second threshold, the difference is divided into three intervals with different physical meanings. The first threshold is usually not greater than zero, for example, it can be set to 0 degrees Celsius or -5 degrees Celsius. Setting the first threshold to not be greater than zero is to reserve an extra safety margin based on the measured temperature being lower than the upper temperature limit. When the difference is less than or equal to the first threshold, it indicates that the temperature in that area not only has not exceeded the limit, but has also been sufficiently cooled, leaving enough temperature buffer space. At this time, the area is marked as being in a state where normal sand covering is possible.

[0067] The second threshold is greater than zero, and can be set to a preset value between 10 and 20 degrees Celsius. The specific value can be determined based on the curing test data and adhesion strength requirements of the molding sand material at the current temperature. When the difference is greater than the first threshold and less than or equal to the second threshold, it indicates that although the temperature in this area slightly exceeds the dynamic release threshold, the excess is still within the range that the molding sand can withstand or can be recovered through short-term intervention. At this time, the area is marked as requiring treatment, meaning that there is a slight deviation in this area, which can be remedied by delaying or local cooling, without having to terminate the entire process directly.

[0068] When the difference exceeds the second threshold, it indicates that the temperature in that area has significantly exceeded the recoverable deviation range, resulting in excessive internal heat accumulation. Conventional short-term intervention alone is insufficient to restore it to a suitable state for sand covering. In this case, the area is marked as unsuitable for sand covering, indicating the need for manual inspection or a significantly extended cooling time.

[0069] In practical applications, to further improve control accuracy, the first and second thresholds can be set differently based on the region type to which the mesh belongs. For meshes marked as high-risk areas for hot spots, since they correspond to thicker parts of the casting, heat dissipation is slower and the impact on the sand coating quality is more critical, the absolute value of the first threshold can be set larger to require a greater safety margin, while the second threshold can be set smaller to narrow the allowable recoverable deviation range. For ordinary areas, the restrictions on these two thresholds can be appropriately relaxed. This tiered setting helps to ensure the quality of critical areas while also considering the production efficiency of ordinary areas.

[0070] After the above comparison and labeling operations, the information structure of each region has undergone a substantial change. Originally, each grid only had a single physical data point—the measured temperature value—but now it is endowed with structured attributes including differences and status flags. In the work release judgment data table, a status flag field will be added to each grid, whose values ​​can include the enumerated values ​​NORMAL, NEED_PROCESS, and FORBIDDEN, corresponding to three states: normal sand covering, requiring treatment, and no sand covering, respectively.

[0071] Meanwhile, the results of this status classification are also presented intuitively on the management terminal interface. For example, in the iron mold heat map monitoring interface, grids in a normal sand-covering state are marked in green, grids requiring processing are marked in yellow with a flashing indicator, and grids in an unsuitable sand-covering state are marked in red and trigger an alarm message. This visual interactive feedback helps on-site operators quickly locate abnormal areas and reduce cognitive load.

[0072] Through this three-tiered classification mechanism, the sand coating access control has been upgraded from a simple binary decision-making process to a multi-level identification system. For areas with slight deviations, a relatively mild approach can be taken, ensuring the stability of continuous production cycles. For areas with severe deviations, they can be clearly identified and intercepted individually, preventing subsequent process instability caused by the concealment of localized high-heat areas. This graded management based on the degree of deviation makes the control logic of the entire casting process more closely aligned with the thermal behavior patterns in actual production, helping to improve the acceptance quality of the sand coating process from the source.

[0073] In the preceding steps, each grid on the mold surface has been marked as either "suitable for normal sand coating," "requiring treatment," or "unsuitable for sand coating" based on the comparison between measured temperature and dynamic release threshold, and the corresponding differences have been calculated. In actual continuous short-cycle production scenarios, the thermal recovery of different areas on the mold surface is often uneven. Some ordinary areas may have completely cooled, while high-risk hot spots corresponding to thicker parts of the casting may still have accumulated heat. If the entire sand coating process is cut off simply because the temperature of a single ordinary area slightly exceeds the threshold, the production cycle will be disrupted, resulting in equipment idling and wasted capacity. Conversely, if most areas are released blindly as long as they meet the standards, high-risk hot spots that truly affect casting quality may enter the sand coating stage with excessively high temperatures, leading to abnormal sand solidification or poor adhesion. Therefore, a convergent decision-making mechanism that comprehensively considers the risk level and deviation degree of each area is needed to generate the final sand coating control instruction.

[0074] Further, the step of generating a control command to prevent the sand coating process from starting includes: obtaining the preset weights corresponding to each region, wherein the preset weight of a region marked as a high-risk area for hot spots is higher than that of other regions; generating a control command to prevent the sand coating process from starting in response to the existence of a region marked as not suitable for sand coating; calculating a weighted score based on the preset weights and differences of each region in a state requiring treatment in response to the existence of a region not suitable for sand coating; generating a control command to allow the sand coating process to start when the weighted score is lower than a preset allowable delay threshold; and generating a program delay control command when the weighted score is not lower than the preset allowable delay threshold, the program delay control command being used to trigger a local cooling operation when the turning conditions are met.

[0075] Specifically, when obtaining the preset weights for each region, the weight allocation directly reflects the degree of influence of temperature anomalies in that region on the final casting quality. For meshes marked as high-risk thermal points, due to the thicker parts of the corresponding castings, these parts absorb more heat during pouring and dissipate it slowly. If the temperature is too high during sand coating, it can easily cause local overheating and sintering of the molding sand or uneven solidification, resulting in sand adhesion or porosity defects on the casting surface. Therefore, the preset weights for these regions are set to higher values, such as between 0.6 and 0.8. For ordinary regions, their heat capacity is smaller, and the impact of slightly higher temperatures on the sand coating quality is relatively limited. Their preset weights are set to lower values, such as between 0.2 and 0.4. The sum of the preset weights for all meshes is usually normalized to 1. Through this differentiated weight setting, the temperature deviation in high-risk regions can receive a larger calculation weight in subsequent aggregation calculations, thereby preventing the heat accumulation in critical parts from being masked by the normal state of ordinary regions.

[0076] When determining whether there are areas marked as unsuitable for sand coating, if the measured temperature of any grid on the mold surface exceeds its dynamic release threshold and is beyond the recoverable range, a control command will be directly generated to prevent the sand coating process from starting. This veto mechanism is used to safeguard the bottom line of quality, because an unsuitable sand coating state means that the heat accumulation in that area has deviated from the limits allowed by the process. If sand coating is forced at this time, it will lead to casting defects and may even damage the sand coating equipment or the mold itself.

[0077] Assume there are no areas on the current mold surface that cannot be sanded, but there are two areas marked as requiring treatment: grid A and grid B. Grid A is a high-risk area for thermal runaway, with a preset weight of 0.7, and its measured temperature differs from the upper temperature limit by 5 degrees Celsius. Grid B is a normal area, with a preset weight of 0.3, and its difference is 8 degrees Celsius. According to the calculation rules, the preset weights of each area are multiplied by their differences and then summed, i.e., 0.7 multiplied by 5 plus 0.3 multiplied by 8, resulting in a weighted score of 5.9. Assuming the system's preset allowable delay threshold is 6.0, since the currently calculated weighted score of 5.9 is lower than this threshold, the system determines that the overall thermal deviation of the current mold is within the preset manageable range.

[0078] In this situation, a controlled release instruction or a short-term confirmation-based start-up instruction can be generated. The controlled release instruction may include recording the location, difference, and risk level of the area to be treated, prompting operators to pay attention to the corresponding area, or requiring the sand-coating equipment to complete a re-inspection before performing the sand-shooting action. In this way, production can be avoided from being directly interrupted due to slight local deviations, while also preventing the deviated area from being treated as a completely normal area.

[0079] In this case, although sand covering is permitted, the location and current temperature of the areas requiring treatment will be recorded in the release results to prompt operators to pay attention to local areas or conduct manual visual inspections during subsequent sand spraying.

[0080] When the weighted score is not lower than the preset allowable delay threshold, it indicates that the overall thermal deviation has reached a critical point that may affect the sand coating quality. At this point, a process delay control instruction is generated. This instruction, which prevents immediate start by delaying the process, starts a delay timer after generation to avoid directly terminating the current cycle. The timer duration can be set according to the extent to which the weighted score exceeds the threshold; the greater the deviation, the longer the delay, allowing the mold to further reduce its temperature through natural heat dissipation.

[0081] It should be noted that the process delay control command can also carry cooling trigger conditions. The cooling trigger conditions are used to determine whether to switch from the natural delay waiting branch to the active local cooling branch. For example, during the delay waiting period, if a warning of waiting time for subsequent workstations, the production queue waiting time exceeds the preset upper limit, the temperature drop rate of the area to be processed is lower than the preset rate threshold, or the expected natural cooling completion time exceeds the current production cycle allowable range, then the cooling trigger conditions are determined to be met, and a local cooling operation is automatically triggered to locally cool the specific area to be processed, thereby recovering production progress as much as possible while ensuring quality.

[0082] In continuous short-cycle production of iron mold sand casting, after a local cooling device directionally cools the high-heat areas on the iron mold surface, the surface temperature can rapidly drop below the upper limit of the allowable sand coating temperature within a short time due to the thermal inertia of the iron mold material. However, the heat accumulated inside this area will continue to be conducted to the surface for a period of time, causing the surface temperature to potentially rise after cooling. If the surface temperature is only measured once after cooling, and it is directly determined that the area has recovered to a sand-coating state simply because the temperature meets the standard, it is highly likely that a false recovery—a temporary drop in surface temperature while the interior remains hot—will be misjudged as a true recovery. This would lead to the area carrying residual heat that has not been fully dissipated into the sand coating process. Such misjudgment would undermine the aforementioned process start-up state management based on historical heat accumulation and dynamic thresholds, making the localized high-heat areas a potential source of fluctuation in sand coating quality.

[0083] Furthermore, after the local cooling operation is performed, the process also includes: acquiring temperature values ​​collected at least at two different time points in the area targeted by the local cooling operation after the local cooling operation is completed, as well as the time points corresponding to each temperature value; determining whether the area meets the preset stable recovery conditions based on the at least two temperature values, time points, and the upper temperature limit corresponding to the area, the stable recovery conditions are used to indicate that the internal heat of the area has been fully dissipated after the local cooling operation rather than just the surface being temporarily cooled; and prohibiting the use of the area's temperature information to generate control commands that allow the sand coating process to start before determining that the area meets the stable recovery conditions.

[0084] To address this, this application introduces a post-cooling observation phase after the localized cooling operation is completed. During this phase, instead of relying solely on a single temperature reading, the infrared thermal imaging acquisition device or a temperature sensor array deployed in the key area is typically used to perform at least two temperature acquisitions for that area. For example, a first temperature value is acquired at the first moment after cooling ends, and a second temperature value is acquired at a second moment later than the first, with the precise timestamp corresponding to each acquisition recorded. After obtaining these time-varying temperature data, they are combined with the upper temperature limit of the area after historical heat accumulation compensation for analysis.

[0085] The core purpose of the stable recovery condition is to distinguish between actual internal heat loss and temporary surface cooling. In the specific judgment logic, if, over time, the subsequently collected temperature values ​​consistently remain below the upper temperature limit and show a trend of stabilization or continued decline, this indicates that there is no longer significant heat conduction from the interior to the surface, and the heat exchange between the surface and the interior has reached a relatively balanced state. At this point, the region can be considered to meet the stable recovery condition. Conversely, if the subsequently collected temperature values ​​show a significant rebound after a brief period of reaching the target, or even exceed the fluctuation range allowed by the process, this indicates that the cooling action only suppressed the surface temperature, and internal heat is still being released continuously. This region is in a temporary surface cooling state and does not meet the stable recovery condition.

[0086] Before determining that an area meets the stable recovery conditions, its temperature information will be strictly prohibited from being used to generate control commands allowing the sand coating process to begin. Only when it is confirmed that the internal heat has been sufficiently dissipated and the temperature has reached the stable sand coating starting point will the area's status be updated to allow normal sand coating, thus participating in the overall mold release decision. For areas that do not meet the stable recovery conditions, they will remain blocked from the normal release chain, awaiting further delayed observation or processing.

[0087] This mechanism of repeated sampling and stability assessment after cooling can effectively identify and eliminate false recovery situations caused by temporary surface degradation. It can prevent the local high-heat areas from being covered up due to false surface temperature measurement after cooling, thus improving the reliability of local cooling treatment branches and enhancing the accuracy of regional thermal state management in continuous short-cycle production of iron mold sand casting.

[0088] In practice, the duration of the observation phase after cooling can be determined based on the allowable range of the original process cycle time, or it can be set in stages according to the historical thermal inertia of the grid. For example, for high-risk areas of hot spots, due to their larger internal heat capacity and slower heat dissipation, a slightly longer observation window can be used, while for ordinary areas, a shorter observation window can be used. In addition, if the second or subsequent re-collection data is missing within the observation window due to reasons such as data acquisition interruption, it will not be released directly based on the existing qualified re-collection results. It is usually regarded as a critical state of unconfirmed recovery and enters a short-delay re-inspection or manual confirmation branch to prevent wrong release due to missing sampling.

[0089] For different types of regions, the specific parameters for judging the stability recovery conditions can also differ. For example, stricter limits on temperature rise can be set for high-risk areas of thermal spikes to better adapt to the physical heat dissipation characteristics of different regions. The stability judgment results after each cooling can also be recorded as tags in the history of the mesh to trace the thermal recovery history of the region and provide more realistic data support for model correction in subsequent cycles.

[0090] After local cooling operations are completed, simply achieving the target temperature in a single re-mining operation is often insufficient to distinguish between true recovery and temporary surface resurgence. Cooling typically begins on the mold surface, where the surface temperature drops rapidly, but the release of internal heat takes time. If sand coating is allowed solely based on surface cooling, residual internal heat may subsequently re-emerge, causing an abnormally high sand coating interface temperature, rendering sand coating initiation management ineffective at its source. Furthermore, when a region repeatedly cools but fails to achieve stable recovery, it easily falls into an ineffective cooling cycle, wasting production time. To address this, this application proposes a dual progressive judgment logic based on residual margin and reheat change to accurately identify the true recovery state and prevent ineffective processing.

[0091] Further, at least two temperature values ​​include a first temperature value and a second temperature value in chronological order of acquisition time, and time points include corresponding first and second time points, with the second time point being later than the first time point; determining whether the region meets the preset stable recovery conditions includes: calculating the difference between the upper temperature limit and the first temperature value as a margin; calculating the difference between the second temperature value and the first temperature value as a heat return change; when the margin is greater than or equal to the preset stable release margin and the heat return change is less than or equal to the preset heat return limit, the region is determined to meet the stable recovery conditions; when the margin is less than zero, the region is determined not to meet the stable recovery conditions; when the margin is greater than or equal to zero and the heat return change is less than or equal to the preset heat return limit, the region is determined not to meet the stable recovery conditions. When the thermal change exceeds the preset reheat limit, the region is deemed not to meet the stable recovery condition. When the remaining margin is greater than or equal to zero and less than the preset stable release margin, and the reheat change is less than or equal to the preset reheat limit, the third temperature value of the region is obtained after a preset delay. If the third temperature value is less than or equal to the second temperature value, the stable recovery condition is deemed to be met. If the third temperature value is greater than the second temperature value, the stable recovery condition is deemed not to be met. When the same region has undergone two local cooling operations in the current cycle, and the stable recovery condition is not met after each local cooling operation, local cooling operations will no longer be performed on the region, and a control command to prevent the sand covering process from starting will be generated.

[0092] In practice, the first and second temperature values ​​are surface temperature data collected sequentially within the observation window after cooling. The first and second time points clearly define the temporal relationship between these two acquisitions, ensuring the capture of temperature change trends within a short period after cooling. The margin is calculated by subtracting the first temperature value from the upper temperature limit, used to quantify the safe distance of the surface temperature relative to the allowable upper limit. The reheat change is calculated by subtracting the first temperature value from the second temperature value, used to quantify the direction and magnitude of temperature change within the observation window.

[0093] The preset stable release margin and backheat limit serve as reference benchmarks for judgment, and their specific values ​​can be set in tiers according to the type of area. For example, for high-risk areas of hot spots, which are more sensitive to backheating and have a larger internal heat capacity, the stable release margin can be set to 5 to 10 degrees Celsius, and the backheat limit can be set to a smaller value; for ordinary areas, the stable release margin can be set to 2 to 5 degrees Celsius, and the backheat limit can be relaxed accordingly. This tiered setting helps to maintain the smoothness of the production cycle as much as possible while ensuring the quality of sand covering.

[0094] Regarding the judgment logic, when the remaining margin is greater than or equal to the preset stable release margin, the second temperature value is less than or equal to the upper temperature limit, and the amount of heat return change is less than or equal to the preset heat return limit, it indicates that the surface temperature of the area is not only sufficiently lower than the threshold, but also that no heat return phenomenon exceeding the upper temperature limit occurs within the observation window, and the internal heat has been fully dissipated. At this time, the area is judged to meet the stable recovery condition. When the remaining margin is less than zero, it indicates that the temperature of the first re-mining is still higher than the upper temperature limit, which is a state of insufficient cooling, and the area is judged not to meet the stable recovery condition. When the second temperature value is higher than the upper temperature limit, even if the amount of heat return change does not exceed the preset heat return limit, it indicates that the area has exceeded the sand cover release boundary again within the observation window, and the area is judged not to meet the stable recovery condition.

[0095] When the remaining margin is greater than or equal to zero but the amount of heat return exceeds the preset heat return limit, it indicates that although the surface temperature has temporarily met the standard, internal heat is being conducted outward, causing the surface temperature to rise again. This is a temporary surface drop, and the area is also determined not to meet the stable recovery conditions. This dual verification effectively avoids incorrectly assigning areas with only temporary surface cooling and no internal recovery to the subsequent sand coating process.

[0096] For critical states where the remaining margin is greater than or equal to zero and less than the preset stable release margin, the second temperature value is less than or equal to the upper temperature limit, and the amount of heat return change is less than or equal to the preset heat return limit, a final judgment is not made immediately. Instead, the third temperature value of the area is obtained after a preset delay. If the third temperature value is less than or equal to the second temperature value and less than or equal to the upper temperature limit, it indicates that the temperature is stable or continues to decrease and has not yet crossed the sand cover release boundary, thus determining that the stable recovery condition is met. If the third temperature value is greater than the second temperature value, or the third temperature value is higher than the upper temperature limit, it indicates that delayed heat return has occurred or the sand cover release boundary has been crossed again, thus determining that the stable recovery condition is not met. It is worth noting that if the third temperature value is missing due to temporary sensor obstruction or data acquisition interruption during the delayed re-sampling process, it will not be directly judged as stable recovery based on the results of the first two re-samplings. Instead, the area will be treated as a surface temporary drop state, or manual confirmation will be triggered, thereby preventing erroneous release due to missing sampling.

[0097] In the execution management of local cooling operations, a local cooling failure counter is maintained for each grid within the current work cycle. Each time local cooling is performed and stability verification determines that the stable recovery conditions are not met, the counter is incremented. The counter is reset when the work cycle ends or the area is determined to have achieved stable recovery. If the same area has undergone two local cooling operations within the current work cycle, and the stable recovery conditions are not met after each operation, no further local cooling operations will be performed on that area, and a control command will be generated to prevent the sand coating process from starting. This upgraded constraint mechanism breaks the ineffective cooling cycle, shifting the handling of abnormal areas from automatic repetitive attempts to manual intervention or process troubleshooting, avoiding resource waste and unnecessary occupation of production time.

[0098] The stability status conclusions after each cooling cycle, including labels such as stable recovery, surface sag, and insufficient cooling, are recorded in the historical work record table of the grid. These status labels will serve as the basis for sample selection during subsequent model corrections. For example, samples marked as surface sag can be downweighted or directly excluded when subsequently correcting the heat dissipation reference model, avoiding the model being misled by data on temporary surface sags, thereby ensuring the accuracy of dynamic release threshold calculations in subsequent work cycles.

[0099] Reference Figure 2 , Figure 2 The overall control process of the iron mold sand casting process management method is demonstrated. Figure 2In the process, the system first obtains the measured temperature information of the current operation based on the thermal management grid of the iron mold surface, and determines the residual heat deviation of each grid by combining the historical information of heat dissipation from previous operations and the thermal response reference relationship. Then, it determines the upper limit of the allowable sand coating temperature for the current operation based on the upper limit of the reference temperature and the residual heat deviation. Subsequently, by comparing the measured temperature with the upper limit of the temperature, the system marks the status of each grid, and the control command generation module generates control commands to prevent sand coating, allow sand coating, or delay the process. For the areas that need to be processed and enter the process delay treatment, a local cooling operation is performed when the cooling trigger condition is met, and after the local cooling operation, it is determined whether the area meets the stable recovery condition based on the temperature values ​​at multiple time points.

[0100] Subsequently, the system calculates the difference between the corresponding upper temperature limit and the first temperature value, and uses this difference as the remaining margin; simultaneously, it calculates the difference between the second temperature value and the first temperature value, and uses this difference as the regenerative change. Based on this data, the system executes the following decision logic: First, when the calculated remaining margin is greater than or equal to the preset stable release margin, the second temperature value is less than or equal to the upper temperature limit, and the amount of heat return change is less than or equal to the preset heat return limit, it indicates that the cooling effect in the area is ideal and the thermal state is stable, and the area is determined to meet the stable recovery conditions.

[0101] Second, when the remaining margin is less than zero, it means that even after cooling, the temperature of the first re-mining still exceeds the standard, and it is directly determined that the area does not meet the conditions for stable recovery.

[0102] Third, when the second temperature value is higher than the upper temperature limit, it indicates that the area has crossed the sand release boundary again within the observation window, and the area is determined not to meet the stable recovery conditions; when the remaining margin is greater than or equal to zero, but the amount of heat return change is greater than the preset heat return limit, it indicates that although the surface of the area has cooled down, the internal heat is still being rapidly conducted to the surface, and the area is also determined not to meet the stable recovery conditions.

[0103] Fourth, when the remaining margin is greater than or equal to zero and less than the preset stable release margin, the second temperature value is less than or equal to the upper temperature limit, and the amount of backheating change is less than or equal to the preset backheating limit, it indicates that the region is in a critical state. At this time, the system obtains the third temperature value of the region after a preset delay. If the third temperature value is less than or equal to the second temperature value and the third temperature value is less than or equal to the upper temperature limit, it indicates that the temperature has stabilized or continues to decrease and is still within the sand-covered release boundary, and the stable recovery condition is met; if the third temperature value is greater than the second temperature value, or the third temperature value is higher than the upper temperature limit, it indicates that there is still backheating or the sand-covered release boundary has been crossed again, and the stable recovery condition is not met.

[0104] Before determining that the region meets the conditions for stable recovery, the system prohibits the use of the temperature information of that region to generate control commands that allow the sand coating process to start, in order to ensure casting quality.

[0105] In addition, to avoid infinite cooling cycles, the system records the number of cooling cycles. If the same area has undergone two local cooling operations in the current cycle, and the stable recovery conditions cannot be met after each local cooling operation, the system will no longer perform local cooling operations on that area, and will directly generate a control command to prevent the sand covering process from starting, thus entering the exception handling process.

[0106] During long-term continuous production, the actual heat dissipation characteristics of the iron mold gradually drift due to surface oxidation, ambient temperature fluctuations, and fine-tuning of the production cycle. If the initial thermal response reference relationship is relied upon to estimate the residual heat deviation of previous processes, the calculation results may contain systematic errors, leading to a continuously loose or tight dynamic release threshold, which in turn affects the long-term accuracy of sand-covered release judgment. To address this, this application proposes a mechanism for online correction of the thermal response reference relationship after the current process is completed.

[0107] Furthermore, after the current process is completed, the process also includes: obtaining the surface temperature of each grid in the mold before the next sand covering, as feedback temperature information; obtaining the time elapsed from the end of the current pouring process to the acquisition of feedback temperature information, as calibration duration information; and correcting the thermal response reference relationship based on the initial temperature, feedback temperature information, and calibration duration information of each grid at the end of the current pouring process. The corrected thermal response reference relationship is used to determine the residual heat deviation of subsequent processes.

[0108] Specifically, the completion of the current cycle signifies that the mold has undergone a complete cycle of sand coating, pouring, cooling, and mold opening, and is entering the preparation stage for the next production run. At this point, each grid in the mold has experienced a complete high-temperature heating and natural cooling process. Using an array of temperature sensors or a non-contact infrared thermal imaging acquisition device placed on the mold surface, the actual surface temperature of each grid can be collected when the next sand coating preparation begins, serving as feedback temperature information. Simultaneously, the specific time of completion of the current pouring cycle is extracted from the production execution system records, and the time difference between that moment and the time of collecting the feedback temperature information is calculated, serving as calibration duration information. Combined with the initial temperature of each grid recorded in previous steps at the end of the current pouring cycle, a true temperature decay sample is obtained, representing the complete physical process of the temperature dropping from the initial temperature to the feedback temperature after the calibration duration.

[0109] It is worth noting that this application introduces this correction mechanism because after repeated exposure to high-temperature molten iron and cooling, an oxide layer forms on the surface of the mold. Furthermore, the ambient temperature and ventilation conditions in the workshop vary with the seasons and shifts. These changes in physical and environmental factors directly lead to a slight but continuous shift in the actual heat dissipation coefficient and heat capacity of the mold. To eliminate the cumulative error caused by this shift, it is necessary to compare the obtained actual temperature decay samples with the currently used thermal response reference relationship.

[0110] The specific comparison and correction logic is as follows: Substitute the initial temperature and calibration duration into the current thermal response reference relationship to calculate the theoretical temperature value predicted by the relationship. Then, calculate the deviation between this theoretical temperature value and the actual collected feedback temperature information. Based on this deviation, a recursive parameter estimation method is used to fine-tune the shape parameters such as the heat dissipation coefficient and time constant in the thermal response reference relationship. For example, newly acquired actual decay data can be used as new samples, given a higher weight, while the weight of historical samples is reduced. The model parameters are gradually updated through iterative calculations, so that the temperature decrease curve depicted by the corrected thermal response reference relationship more closely matches the actual heat dissipation behavior of the iron mold.

[0111] As an optional implementation, the correction action can be automatically triggered after each cycle, or it can be initiated only when the average prediction deviation of multiple consecutive cycles exceeds a preset threshold, thus balancing computational resources and correction accuracy. Furthermore, during the correction process, if data measured immediately after cooling of certain meshes shows a significant temporary drop in surface temperature while internal heat remains, the weight of such anomalous samples during parameter updates can be reduced, or they can be excluded entirely, preventing the model from being misled by inaccurate surface cooling data. The corrected thermal response reference relationship is saved in the model parameter library and directly invoked when calculating residual heat deviation in subsequent cycles. Through this online adaptive correction, the estimation of residual heat deviation is no longer limited to a static model but can dynamically adjust according to the actual changes in the heat dissipation characteristics of the mold, helping to prevent systematic deviations in the dynamic release threshold and thus maintaining the consistency and reliability of sand coating start-up management during long-term continuous production.

[0112] This application also proposes a sand-coated casting process management system for iron molds, used to execute the method steps described above, including: an information acquisition module for acquiring measured temperature information of multiple regions on the iron mold before sand coating in the current cycle, and historical information on the heating and heat dissipation of multiple regions in previous cycles; a residual deviation determination module for determining the residual heat deviation of each region at the current moment due to heat accumulation in previous cycles, based on the heating and heat dissipation historical information; a threshold determination module for determining the upper limit of the allowable sand coating temperature for each region in the current cycle, based on the residual heat deviation; and a comparison control module for comparing the measured temperature information of each region with the corresponding upper limit of temperature, and generating a control command to prevent the sand coating process from starting when the measured temperature information of a region is higher than the corresponding upper limit of temperature.

[0113] The above scheme allows for independent assessment and release management of the thermal recovery degree of each key area of ​​the mold before sand coating, making the start-up conditions of the sand coating process more consistent with the actual local thermal state of the mold, reducing the deviation of the sand coating start point caused by the failure to identify local heat accumulation and its impact on subsequent processes.

[0114] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. All modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for managing the process of iron mold sand casting, characterized in that, include: Obtain measured temperature information of multiple areas on the iron mold before sand coating in the current process, as well as historical information on the heating and heat dissipation of multiple areas in previous processes; Based on historical information on heat absorption and dissipation, determine the residual heat deviation of each region at the current moment due to heat accumulation from previous processes. Based on the residual heat deviation, determine the upper limit of the allowable sand covering temperature for each area in the current work cycle; The measured temperature information of each area is compared with the corresponding upper temperature limit. When the measured temperature information of an area is higher than the corresponding upper temperature limit, a control command is generated to prevent the sand covering process from starting.

2. The method for managing the iron mold sand-coated casting process according to claim 1, characterized in that, Multiple regions are obtained by dividing the iron mold surface into multiple thermal management grids; In multiple thermal management grids, grids applied to thick or hot spots in castings are marked as high-risk areas for hot spots. Obtain measured temperature information for multiple regions on the mold before sand coating in the current process, including: obtaining the surface temperature corresponding to each thermal management grid.

3. The method for managing the iron mold sand-coated casting process according to claim 2, characterized in that, The heating and cooling history information includes the initial temperature of each grid at the end of each pouring in the most recent N preceding pouring cycles and the first duration from the end of that pouring cycle to the current moment; The steps to determine the residual heat deviation of each region at the current moment due to heat accumulation from previous processes include: Obtain a thermal response reference relationship to characterize the temperature decay over time after a single pouring; For each grid, based on the starting temperature and first duration of each of the last N operations, the residual influence component of that operation at the current moment is determined using the thermal response reference relationship. The residual influence components of the most recent N cycles are weighted and superimposed to generate the residual heat deviation of the grid at the current moment.

4. The method for managing the iron mold sand casting process according to claim 3, characterized in that, Based on the residual heat deviation, determine the upper limit of the allowable sand covering temperature for each area in the current work cycle, including: For each grid, obtain a reference temperature upper limit to characterize the highest allowable sand covering temperature for that grid without prior heat accumulation; Subtracting the residual heat deviation of the grid from the reference temperature upper limit yields the upper limit of the allowable sand covering temperature for the grid in the current operation.

5. The method for managing the iron mold sand-coated casting process according to claim 4, characterized in that, The steps for comparing the measured temperature information of each region with the corresponding upper temperature limit include: For each region, calculate the difference between the measured temperature information and the upper temperature limit; When the difference is less than or equal to a preset first threshold, the area is marked as a state where sand can be covered normally. The first threshold is not greater than zero. When the difference is greater than the first threshold and less than or equal to the preset second threshold, the area is marked as a state that needs to be processed. The second threshold is greater than zero. When the difference is greater than the second threshold, the area is marked as unsuitable for sand covering.

6. The method for managing the iron mold sand-coated casting process according to claim 5, characterized in that, The steps for generating control instructions to prevent the sand coating process from starting include: Obtain the preset weights corresponding to each region. Areas marked as high-risk hotspots have a higher default weight than other areas; In response to the existence of areas marked as unsuitable for sand covering, a control command is generated to prevent the sand covering process from starting. In response to areas where there are no areas that cannot be covered by sand and areas that are marked as needing to be processed, a weighted score is calculated based on the preset weights and differences of the areas in each needing-to-be-processed state. When the weighted score is lower than the preset allowable delay threshold, a control command is generated to allow the sand covering process to start. When the weighted score is not lower than the preset allowable delay threshold, a program delay control instruction is generated. The program delay control instruction is used to trigger a local cooling operation when the steering conditions are met.

7. The method for managing the iron mold sand-coated casting process according to claim 6, characterized in that, After the localized cooling operation is performed, the following is also included: Acquire temperature values ​​of the area targeted by the local cooling operation at at least two different time points after the local cooling operation is completed, as well as the time points corresponding to each temperature value; Based on at least two temperature values, time points, and the upper limit of the temperature corresponding to the region, determine whether the region meets the preset stable recovery conditions. The stable recovery conditions are used to indicate that the internal heat of the region has been fully dissipated after the local cooling operation rather than just the surface being temporarily cooled. Before a region is determined to meet the conditions for stable recovery, it is prohibited to use the region's temperature information to generate control commands that allow the sand covering process to start.

8. The method for managing the iron mold sand casting process according to claim 7, characterized in that, At least two temperature values ​​include a first temperature value and a second temperature value in chronological order of acquisition time, and time points include corresponding first time points and second time points, with the second time point being later than the first time point; Determine whether the region meets the preset stable recovery conditions, including: The difference between the upper temperature limit and the first temperature value is calculated as the remaining margin; The difference between the second temperature value and the first temperature value is calculated as the reheat change. When the remaining margin is greater than or equal to the preset stable release margin and the heat return change is less than or equal to the preset heat return limit, the region is determined to meet the stable recovery condition. When the remaining margin is less than zero, the region is determined to be not in a stable recovery condition; When the remaining margin is greater than or equal to zero and the amount of heat return is greater than the preset heat return limit, the judgment area does not meet the stable recovery condition. When the remaining margin is greater than or equal to zero and less than the preset stable release margin, and the amount of heat return change is less than or equal to the preset heat return limit, the third temperature value of the area is obtained after a preset delay. If the third temperature value is less than or equal to the second temperature value, it is determined that the stable recovery condition is met. If the third temperature value is greater than the second temperature value, it is determined that the stable recovery condition is not met. If the same area has undergone two local cooling operations in the current cycle, and the stable recovery conditions are not met after each local cooling operation, no more local cooling operations will be performed on that area, and a control command will be generated to prevent the sand covering process from starting.

9. The method for managing the iron mold sand-coated casting process according to claim 3, characterized in that, After the current task is completed, it also includes: The surface temperature of each grid in the iron mold before the next sand coating is obtained as feedback temperature information; The time elapsed from the end of the current pouring cycle to the acquisition and feedback of temperature information is used as the calibration duration information; The thermal response reference relationship is corrected based on the initial temperature, feedback temperature, and calibration duration information of each grid at the end of the current pouring cycle. The revised thermal response reference relationship is used to determine the residual heat deviation in subsequent cycles.

10. A process management system for iron mold sand casting, used to execute the process management method for iron mold sand casting according to any one of claims 1 to 9, characterized in that, include: The information acquisition module is used to acquire the measured temperature information of multiple areas on the iron mold before the current sand coating process, as well as the historical information of the heating and heat dissipation of multiple areas in the previous multiple processes. The residual deviation determination module is used to determine the residual heat deviation of each area at the current moment due to the heat accumulation of the previous process, based on the heating and heat dissipation history information. The threshold determination module is used to determine the upper limit of the allowable sand covering temperature for each area in the current work cycle based on the residual heat deviation. The comparison control module is used to compare the measured temperature information of each area with the corresponding upper temperature limit. When the measured temperature information of an area is higher than the corresponding upper temperature limit, a control command is generated to prevent the sand covering process from starting.

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