A method for controlling temperature in a region of a mold for an automotive component

Abstract

The present application belongs to the technical field of mold area temperature control, and in particular relates to a kind of automobile parts mold area temperature control method, by the wall thickness based on mold channel and heat distribution refinement segmentation mold channel temperature control area, the fine division of temperature control area is realized, and by combining planned cooling time accurate adjustment each temperature control area, it can avoid or reduce the event that product cooling is not uniform and forming quality is poor due to not considering wall thickness, to optimize cooling uniformity and improve injection molding quality, simultaneously by the temperature value and the distance between regions according to each temperature region, the mode that the region needing regulation and control is adopted single regulation and control, group regulation and control and the combination of overall regulation and control, make up the deficiency of current single temperature regulation mode, so as to quickly reach the preheating requirement, and save regulation and control time, to improve the regulation and control efficiency and avoid energy waste.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of mold area temperature control, and particularly relates to a mold area temperature control method for automobile parts. BACKGROUND

[0002] Automobile parts are generally produced by injection molding, and the temperature control in the injection molding process directly determines the production yield, so the temperature control is particularly important in the production and processing of automobile parts.

[0003] The prior art such as the cooling regulation method and system for an injection mold disclosed in Chinese Patent Application No. 202510939620.X obtains real-time temperature data through a temperature sensor of a preset measuring point of a mold cavity, generates a heat distribution model and divides corresponding sub-cooling areas of the cooling circuit, and then generates a flow regulation instruction according to the temperature state of each area to control the electric control valve and the variable frequency water pump to regulate the cooling fluid flow, so as to realize the partitioned and accurate regulation of the cooling process of the injection mold.

[0004] According to the above prior art, it can be known that the current regulation and control partition is mainly based on temperature distribution, and the details of how to regulate are not paid enough attention to, and there are still the following problems: 1. The influence of the mold wall thickness difference on the final effect of temperature regulation in the temperature control process is not considered, which causes inconsistent cooling or preheating of the finished product, and causes quality problems such as product shrinkage, deformation or size precision not meeting the standard requirements.

[0005] 2. The current only judges the temperature area that needs to be regulated and performs corresponding regulation, and does not consider the mold structure characteristics such as wall thickness difference and shape regularity. This single regulation method takes a long time, and when there are multiple places that need to be regulated, the current regulation method is difficult to meet the production demand, and it is also difficult to ensure the accuracy and effectiveness of the regulation.

[0006] 3. The current regulation is performed according to the separate regulation principle, without considering the similarity of the regulation values and the distance between the regulation positions when multiple regulations are performed, which may cause energy waste, difficulty in timely completing the production plan, and difficulty in ensuring the consistency of the temperature in each area, thereby affecting the overall performance of the injection molded part. SUMMARY

[0007] In view of this, in order to solve the above problems, a mold area temperature control method for automobile parts is provided.

[0008] The purpose of the application can be achieved by the following technical scheme: the application provides a mold area temperature control method for automobile parts, which comprises: detecting the overall cavity of the mold by a thermal imager to generate a thermal image, and identifying the thermal image to obtain temperature information.

[0009] Screening the cavity position not meeting the injection preheating requirement based on temperature information, and starting the temperature control unit in the position to perform corresponding temperature regulation until the injection preheating requirement is met.

[0010] The temperature value of the cavity after injecting the molten injection material is collected in real time by the temperature sensor built in the mold, the temperature regulation cavity position is determined according to the current temperature value collected by the temperature sensor and the distribution position and the overall cavity three-dimensional space position coordinates, and corresponding cavity temperature regulation is performed.

[0011] After the injection is completed and the pressure maintaining process is ended, the overall cavity is divided into several temperature control regions according to the structural characteristics of the overall cavity, and the current temperature is collected according to the temperature sensor built in each temperature control region.

[0012] The matched temperature adjustment strategy is obtained by matching the preset temperature control model according to the current temperature of each temperature control region, the injection material characteristics, the mold material characteristics and the planned cooling time, and the cooling regulation is performed according to the temperature adjustment strategy.

[0013] Compared with the prior art, the beneficial effects of the present application are as follows: (1) The present application realizes the fine division of the temperature control region by refining the temperature control region of the mold cavity based on the wall thickness and heat distribution of the mold cavity, and can avoid or reduce the occurrence of events such as uneven cooling of the finished product and poor molding quality caused by not considering the wall thickness, thereby optimizing the cooling uniformity and improving the injection molding quality.

[0014] (2) The present application adopts the combination of individual regulation, grouped regulation and overall regulation for the regulation region according to the temperature value of each temperature region and the distance between regions, which makes up for the shortcomings of the current single temperature regulation mode, so as to quickly meet the preheating requirement and save regulation time, thereby improving the regulation efficiency and avoiding energy waste.

[0015] (3) The present application adjusts the temperature control region from three dimensions of temperature difference, wall thickness difference and regularity by combining the structural characteristics of the mold cavity and the characteristics of the injection material, automatically starts region division when any dimension exceeds the preset threshold, avoids the lack of pertinence in current temperature control region division, thereby closely linking the temperature control region division and the product quality, and further having clear pertinence and ensuring the injection molding quality. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creating any creative labor.

[0017] Figure 1 The whole implementation process of the present application is shown in the schematic diagram.

[0018] Figure 2 The temperature regulation execution process of the preheating of the present application is shown in the schematic diagram.

[0019] Figure 3 The basic area adjustment process of the present application is shown in the schematic diagram.

[0020] Figure 4 The segmentation process of the present application according to the preset segmentation rule is shown in the schematic diagram. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0022] Please refer to Figure 1 The present application provides a mold area temperature control method for automobile parts, which comprises the following steps: S1, detecting the overall cavity of the mold by a thermal imager to generate a thermal image, and identifying the thermal image to obtain temperature information.

[0023] The process of obtaining the temperature information comprises: introducing a three-dimensional model of the overall cavity to correct the distortion of the thermal image, and then establishing a mapping relationship between the thermal image pixels and the three-dimensional spatial position coordinates of the overall cavity by a SIFT algorithm.

[0024] The thermal image is identified to obtain each temperature region and the temperature value of the corresponding temperature region, and the cavity position to which each temperature region belongs is marked.

[0025] The temperature value corresponding to each temperature region and the cavity position to which each temperature region belongs are combined to form the temperature information.

[0026] The distortion correction is an existing image processing method, which is not described in detail in the present application. The SIFT algorithm is an existing mapping algorithm, which is not described in detail in the present application.

[0027] S2, based on the temperature information, the cavity positions that do not meet the preheating requirements for injection molding are screened, and the temperature control units in the positions are started to perform corresponding temperature regulation until the preheating requirements for injection molding are met, and then injection molding is performed.

[0028] The preheating requirements for injection molding are preheating threshold values for injection molding. The preheating threshold values for injection molding can be obtained by consulting the injection temperature reference table of different materials provided by the supplier and the past actual production case analysis report, etc.

[0029] The process of screening the cavity position not meeting the injection preheating requirement comprises: matching the preset preheating standard temperature value of the corresponding temperature region based on the cavity position to which each temperature region belongs.

[0030] Comparing the temperature value corresponding to each temperature region with the preset preheating standard temperature value thereof.

[0031] If the temperature value corresponding to a certain temperature region is lower than the preset preheating standard temperature value thereof and the difference between the temperature value and the preset preheating standard temperature value exceeds the preset allowable range, the temperature region is marked as the cavity position not meeting the injection preheating requirement.

[0032] It should be noted that the preset preheating standard temperature value mentioned above can be obtained by a large number of experimental calculations or by consulting an injection process parameter reference table. When the experimental calculation is adopted to determine, the mold temperature recommended by the material can be taken as the center, 3-5 groups of gradient temperatures are set, then injection is carried out at different preheating temperatures, product defects are detected, the critical temperature of no defect and defect is found, and the critical temperature of no defect and defect is found again under extreme conditions such as environmental temperature fluctuation and continuous production, and the lowest defect-free temperature is taken as the preset preheating standard temperature value of the region, thereby ensuring the applicability of the preset preheating standard temperature value.

[0033] Understandably, the preset preheating standard temperature value mentioned above, i.e. the lowest preheating temperature that the mold cavity needs to reach before injection, ensures that the molten material can flow, fill and reduce defects after injection.

[0034] It should be noted that the preset allowable range of the preheating standard temperature value mentioned above needs to be set comprehensively according to the mold material properties, injection material properties, injection process requirements and production stability requirements. The preset preheating standard temperature value can be taken as the benchmark, and the wall thickness, heat sensitivity and influence on the quality of injection parts of different temperature regions are comprehensively set. A floating interval of ±3℃-±8℃ is set by default, for example, a smaller range of ±3℃-±5℃ is taken for a thin-walled region with high forming precision requirement, and a larger range of ±5℃-±8℃ is taken for a thick-walled or non-critical region.

[0035] Among them, the mold material properties include mechanics, heat and machining properties. The mechanical properties such as hardness, wear resistance, compressive strength and toughness can withstand high pressure and friction during injection, the thermal properties such as thermal conductivity and thermal expansion coefficient affect the heat transfer efficiency and mold size stability, and the machining properties such as machinability and polishing property determine the precision and surface quality of the mold cavity.

[0036] The injection material properties include thermal, mechanical, flowability and chemical stability, thermal properties such as thermal conductivity, specific heat capacity, melting temperature, crystallization temperature, mechanical properties such as tensile strength, impact toughness, hardness, elastic modulus, flowability such as melt flow rate, viscosity variation with temperature or shear rate, chemical stability such as corrosion resistance and aging resistance.

[0037] Referring to Figure 2 As shown, the step of corresponding temperature regulation includes: recording the cavity position that does not meet the injection preheating requirement as a regulation position, and counting the number of regulation positions.

[0038] When there is only one regulation position, the difference between the corresponding temperature value of the regulation position and the preset preheating standard temperature value is taken as the regulation temperature value, and the temperature control unit in the regulation position is started based on the regulation temperature value to execute the heating instruction.

[0039] When there are more than one regulation positions, the distance between each regulation position is counted.

[0040] If the maximum distance does not exceed the preset interval distance and the standard deviation of the regulation temperature values of each regulation position is less than the preset threshold value, the regulation positions are connected to generate an overall regulation area.

[0041] The average regulation temperature value of each regulation position is taken as the regulation temperature value of the overall regulation area, and the temperature control unit in the overall regulation area is started based on the regulation temperature value to perform heating.

[0042] If the distance between certain adjacent regulation positions exceeds the preset interval distance or the distance between the adjacent regulation positions does not exceed the preset interval distance and the difference between the regulation temperature values of the adjacent regulation positions exceeds the preset adjacent regulation temperature difference, the temperature control units in the adjacent regulation positions are respectively started based on the regulation temperature values to perform heating.

[0043] All adjacent regulation positions are traversed, and adjacent regulation positions with a distance less than the preset interval distance are marked for binding, and all adjacent regulation positions that are continuously marked for binding form an overall regulation group.

[0044] The average regulation temperature value of each cavity position in the overall regulation group is taken as the regulation temperature value of the overall regulation group, and the temperature control unit of the overall regulation group is started based on the regulation temperature value to execute the heating instruction.

[0045] It should be noted that the temperature control unit mentioned above is integrated by the heating unit and the cooling unit. The heating unit can be a heating tube for small cavity area or complex structure area for rapid heating, or a medium heating tube for high temperature uniformity area. The cooling unit can be a straight-through cooling medium channel, or a spray cooling device. The medium can be water by default, and the spray cooling device usually adopts an industrial mold spray cooling system integrated with multiple adjustable nozzles and a temperature sensor sensing array.

[0046] It should be noted that the preset threshold of the control temperature value of each control position is determined comprehensively in combination with the consistency of temperature control in the overall control area, the similarity of temperature requirements of each control position, the quality requirements of the injection molded part, and the material of the injection molded part. For example, when the finished product is a glass fiber reinforced PA power system key component, the default value is usually 2℃. When the finished product is a PC electronic component shell, the default value is usually 3℃. When the finished product is an ABS interior trim part, the default value is usually 4℃.

[0047] Understandably, the preset threshold of each control position mentioned above is a critical value for determining whether the standard deviation of the control temperature values of multiple control positions is acceptable, which is used to determine whether to merge them into an overall control area.

[0048] It should be noted that the preset interval distance of each control position mentioned above is based on the effective range of the temperature control unit and the synergy of temperature control of adjacent areas, combined with the mold structure and the thermal conductivity of the material, and the maximum spatial distance that can ensure the temperature uniformity when adjacent positions are controlled is taken as the preset interval distance. It is usually set to 5mm-15mm, and the specific value can be selected according to the specific structure and precision of the mold. The more complex the injection mold structure, the higher the precision, and the smaller the value.

[0049] It should be noted that the preset adjacent control temperature difference mentioned above represents the temperature difference required to be met for overall control between two adjacent control positions that meet the preset interval distance.

[0050] It should be noted that the setting of the preset adjacent control temperature difference mentioned above needs to be determined comprehensively according to the thermal conductivity of adjacent control positions, the mold structure relevance, and the quality requirements of the injection molded part, as well as the distance between them, the material thermal diffusion coefficient, and the influence degree on the molding precision. It is usually set to 5℃-10℃, and the specific value can be selected according to the influence degree. The influence degree and the preset adjacent control temperature difference are inversely proportional, usually presented in percentage form. For example, when the influence degree is 100%, the value is 5℃, when the influence degree is 0, the value is 10℃, and when the influence degree is 60%, the value is 8℃.

[0051] The embodiment of the present application adopts the combination of individual regulation, grouped regulation and overall regulation for the region to be regulated according to the temperature value and the distance between regions, makes up for the deficiency of the current single temperature regulation mode, so as to quickly reach the preheating requirement and save the regulation time, thereby improving the regulation efficiency and avoiding energy waste.

[0052] S3, collecting the temperature value of the cavity after injecting the molten injection molding material through the temperature sensor built in the mold, determining the temperature regulation cavity position according to the current temperature value, the distribution position and the overall cavity three-dimensional space position coordinates collected by the temperature sensor, and performing temperature regulation on the corresponding cavity.

[0053] In the step S3, the method for determining the temperature regulation cavity position comprises: comparing the distribution position of each temperature sensor with the overall cavity three-dimensional space position coordinates to obtain the mapping cavity position of each temperature sensor.

[0054] Based on the mapping cavity position of each temperature sensor, a preset injection threshold corresponding to the mapping cavity position is matched.

[0055] The current temperature value collected by each temperature sensor is compared with the preset injection threshold of the mapping cavity position thereof.

[0056] If the current temperature value collected by a certain temperature sensor is lower than the preset injection threshold of the mapping cavity position thereof and the difference between the current temperature value and the preset injection threshold exceeds the preset allowable range, the mapping cavity position of the temperature sensor is marked as the temperature regulation cavity position.

[0057] Further, the specific steps of performing temperature regulation on the corresponding cavity in the step S3 are as follows: taking the difference between the current temperature value of the temperature regulation cavity position and the preset injection threshold as the preliminary cavity regulation temperature value.

[0058] According to the preliminary cavity regulation temperature value, the wall thickness of the temperature regulation cavity position and the cavity material characteristics, a target cavity regulation temperature value is calculated.

[0059] The temperature control unit at the regulation cavity position is started to perform cavity temperature regulation according to the target regulation temperature value corresponding to the position.

[0060] In the calculation process of the target cavity regulation temperature value, a comprehensive compensation coefficient is calculated according to the cavity wall thickness and the material thermal characteristics.

[0061] The target cavity regulation temperature value is obtained by correcting the preliminary cavity regulation temperature value according to the comprehensive compensation coefficient, wherein the correction refers to multiplying the comprehensive compensation coefficient by the preliminary cavity regulation temperature value.

[0062] Specifically, the expression of the comprehensive compensation coefficient is: wherein is the cavity wall thickness, reflects the cavity wall thickness interacts with the thermal conductivity the influence of the interaction on the temperature compensation, can be obtained by regression fitting of temperature measurement experiments of a mold with a similar cavity structure of a large number of same materials, characterizes the thermal response speed The weight of the compensation can be calibrated based on the dynamic temperature measurement curve of different temperature control units, is the correction value to offset the mold base temperature difference, which can be determined by an empty mold steady-state temperature measurement experiment, is the thermal response speed, which refers to the length of time or the rate of temperature change with the control instruction for the temperature control unit to adjust from the current temperature state to the target temperature and reach stability after receiving the heating or cooling instruction. It can be obtained through a large number of experiments.

[0063] It should be noted that the specific process of obtaining a large number of experiments is to start the temperature sensor in the actual injection mold or simulated temperature control environment to collect data in real time, record the time from the initial temperature to the target temperature or calculate the temperature change per unit time.

[0064] wherein the time to reach the target temperature 0.5℃~1℃ stable interval.

[0065] using the above , and is to adapt to the complex coupling characteristics of injection temperature control, simplify model engineering application, balance theoretical accuracy and production robustness, and ensure stable production.

[0066] Understandably, the above-mentioned preset injection threshold corresponding to the mapped cavity position is determined based on the structural characteristics of the mapped cavity position, such as wall thickness, curvature, injection material melting characteristics, and molding quality requirements, combined with the functional importance of the position in the injection molded part. The default value range is usually 220℃~260℃, and the specific value can be selected based on the structural characteristics of the finished product and its material thermal properties, for example, when the finished product is a thick-walled high-curvature transmission part with PA+glass fiber material, the value is 255℃, when the finished product is a precision hole electronic shell with PC material, the value is 245℃, and when the finished product is a thin-walled low-curvature interior trim part with ABS material, the value is 225℃.

[0067] wherein the standard definition rule for functional importance is that positions directly affecting the core function of the injection molded part, such as transmission and sealing, and bearing, are high importance, and positions only bearing non-core functions such as decoration and auxiliary positioning are low importance.

[0068] It should be noted that the preset injection threshold mentioned above represents the temperature at which the injection material can continue to flow smoothly through the mapping cavity position during injection.

[0069] The importance of the cavity position is determined as follows: if the cavity position is a key function implementation area of the injection part, such as a fluid passage cavity, a force structure cavity, and its molding quality directly affects the core indicators such as the sealing performance and mechanical bearing capacity of the injection part, it is determined to be high importance, and if it is only used for process assistance, such as exhaust cavity, non-key positioning cavity, and is not directly related to the core function, it is determined to be low importance.

[0070] It should be noted that the preset allowable range mentioned above represents the maximum deviation range allowed between the current temperature value of the mapping cavity position and the preset injection threshold, which can be set in a targeted manner in combination with the importance of the cavity position, the material properties and the temperature control accuracy requirements.

[0071] S4, when the injection is completed and the pressure maintaining process is ended, the overall cavity is divided into several temperature control regions according to the structural characteristics of the overall cavity, and the current temperature is collected according to the temperature sensor built in each temperature control region.

[0072] Specifically, the division method of the temperature control region includes: A1, marking each key node in the three-dimensional model of the overall cavity, taking the key node as the segmentation endpoint, and taking the connecting line of the region where the key node is located as the segmentation line, and dividing the overall cavity into several basic regions.

[0073] A2, based on the structural parameters of the cavity, the thermal conductivity and the specific heat capacity of the injection material, the current heat distribution of each basic region is simulated, and the maximum temperature difference and the average temperature value of the basic region are obtained according to the heat distribution.

[0074] A3, extracting the three-dimensional profile of each basic region, identifying the wall thickness of each cavity position point in the corresponding basic region based on the three-dimensional profile, counting the average cavity wall thickness of each basic region, and extracting the maximum wall thickness.

[0075] A4, based on the maximum temperature difference, the average temperature value, the three-dimensional profile, the average cavity wall thickness and the maximum wall thickness of each basic region, and the wall thickness of each cavity position point in each basic region, the basic region is adjusted, and the final each temperature control region is output.

[0076] The embodiment of the present application refines the temperature control region of the mold cavity by the wall thickness and heat distribution of the mold cavity, realizes the fine division of the temperature control region, and accurately adjusts each temperature control region by combining the planned cooling time, which can avoid or reduce the occurrence of events such as uneven cooling of finished products and poor molding quality caused by not considering the wall thickness, thereby optimizing the cooling uniformity and improving the injection molding quality.

[0077] Referring to Figure 3 As shown, the process of adjusting the base area in the A4 step includes: A41, identifying the three-dimensional contour of each base area to obtain the regularity of each base area.

[0078] It should be noted that the calculation method of the regularity includes: obtaining the projection plane contour shape of each base area according to the three-dimensional contour, and if the projection plane contour shape of a certain base area is similar to a circular shape, the base area is divided into several groups of sub-contours by sector division.

[0079] Wherein, the similar refers to the coincidence rate of the projection plane contour and the contour of the circle or rectangle being greater than a preset coincidence rate threshold, and the preset coincidence rate threshold is set based on a similar experience threshold.

[0080] If the projection plane shape of a certain base area is similar to a rectangular shape, the base area is divided into multiple groups of sub-contours by plane grid division.

[0081] Each sub-contour in a certain base area is grouped into each contour group by two-by-two, and the sub-contours of each contour group are compared for coincidence to obtain the coincidence rate of each contour group, which is the ratio of the coincidence volume to the larger volume in the contour group.

[0082] The coincidence volumes of each contour group are compared with a preset coincidence volume threshold, and the number of contour groups greater than the preset coincidence volume threshold is counted and recorded as the number of regular contour groups.

[0083] It should be noted that the coincidence volume threshold can be determined by referring to historical effective data of similar injection molding part contour matching, combining mold structure precision requirements and molding quality standards, and experimentally testing and verifying, wherein the historical effective data refers to the coincidence volume related record data that has been verified in practice in the same or similar injection molding part contour matching scene to ensure mold forming precision, avoid contour overlapping defects, and meet production quality standards.

[0084] If the ratio of the number of regular contour groups to the total number of regular contour groups is 1, the final regularity is assigned a value of 1, otherwise the minimum coincidence volume is selected, the ratio of the minimum coincidence volume to the preset coincidence volume threshold is taken as a regularity correction coefficient, and the product of the regularity correction coefficient and the ratio of the number of regular contour groups to the total number of regular contour groups is taken as the final regularity.

[0085] A42, determine whether each base area triggers any of the following conditions, and if so, start the base area adjustment instruction: the maximum temperature difference is greater than the preset temperature difference.

[0086] The difference between the maximum wall thickness and the average channel wall thickness exceeds the preset wall thickness difference.

[0087] The regularity is lower than the preset high regularity threshold.

[0088] like Figure 3 As shown, trigger condition 1 corresponds to a maximum temperature difference greater than a preset temperature difference, trigger condition 2 corresponds to a difference between the maximum wall thickness and the average cavity wall thickness exceeding a preset wall thickness difference, and trigger condition 3 corresponds to a regularity lower than a preset high regularity threshold.

[0089] Understandably, the aforementioned preset temperature difference setting can be determined by taking the influence of temperature distribution uniformity within the basic area on injection molding quality as the core, and combining the material's thermal sensitivity and molding process requirements to comprehensively determine the maximum allowable temperature difference that can ensure temperature control accuracy and injection molded part quality stability in the same area. Furthermore, the specific value of the preset temperature difference can be determined according to the thermal characteristics of the finished product type and material. For example, when the finished product is a precision electronic component made of PC or ABS, the preset temperature difference is 1.5℃; when the finished product is an automotive structural component made of PP + glass fiber, the preset temperature difference is 2℃; and when the finished product is a large interior part made of ABS, the preset temperature difference is 3.5℃.

[0090] It should be noted that the above-mentioned preset temperature difference is the critical temperature difference value for determining whether the basic area needs to be divided. When the maximum temperature difference in the basic area exceeds this value, the area adjustment needs to be initiated.

[0091] It should be noted that the aforementioned preset wall thickness difference focuses on the impact of the uniformity of wall thickness within the basic area on temperature control and injection molding quality. Combining material characteristics and molding requirements, the maximum allowable wall thickness deviation that ensures temperature control consistency and injection molding stability in the same area is taken as the corresponding preset wall thickness difference, which is usually set to 0.1mm to 0.5mm. The specific value needs to be selected according to the precision requirements of the molding process. The preset wall thickness difference is inversely proportional to the precision requirements of the finished product. For example, when the finished product is a thin-walled precision part, the value is 0.1mm, and when the finished product is a medium-sized conventional structural part, the value is 0.25mm.

[0092] Thin-walled precision parts include electronic connectors made of PC, while medium-sized conventional structural parts include door interior panels made of PP.

[0093] Understandably, the aforementioned preset wall thickness difference is the critical value for determining whether the base area needs to be segmented. When the difference between the maximum wall thickness and the average cavity wall thickness in the base area exceeds this value, area adjustment needs to be initiated.

[0094] It should be noted that the preset high regularity threshold, which is the critical value of regularity for determining whether the basic region needs to be adjusted, should be set based on the degree of conformity between the three-dimensional contour of the basic region and the standard geometric shape. It can be set using empirical values ​​of similarity judgment, such as 90%.

[0095] A43. Otherwise, the basic area adjustment will not be performed.

[0096] A44、When the maximum temperature difference of a certain basic region triggers a preset temperature difference, the temperature values of each heat distribution region are obtained based on the heat distribution, and the absolute difference between the temperature values of each heat distribution region and the average temperature of the basic region is calculated. The heat distribution region with an absolute difference exceeding the preset temperature difference value is taken as a new segmentation region.

[0097] A45、When the maximum wall thickness and the average cavity wall thickness of a certain basic region trigger a preset wall thickness difference, if the wall thickness of any cavity position deviates from the average cavity wall thickness of the basic region by an absolute value exceeding the preset wall thickness difference, the cavity position point is taken as a new segmentation point, and a segmentation boundary is generated along the normal direction of the new segmentation point to obtain a new segmentation region.

[0098] A46、When the regularity of a certain basic region triggers a preset high regularity threshold, if the regularity in the basic region is less than the set low regularity threshold, the curvature mutation point of the three-dimensional profile corresponding to the basic region is identified and taken as a new segmentation point, and a segmentation boundary is generated along the new segmentation point to obtain a new segmentation region.

[0099] It should be noted that the above-mentioned low regularity threshold needs to reflect the significant irregularity of the three-dimensional profile of the basic region, and the deviation degree of the region profile from the standard geometric shape is large, and the value range is usually set to 0.3-0.6, and the specific value can be selected according to the production precision requirement of the automobile part.

[0100] Understandably, the above-mentioned low regularity threshold is a critical value for judging whether the basic region is irregular as a whole. When the regularity of all parts in the basic region is lower than the threshold, forced segmentation is needed by identifying the curvature mutation point.

[0101] A47、If the regularity in the basic region is greater than the set low regularity threshold and less than the set high regularity threshold, the preset segmentation rule is used for further segmentation to obtain a new segmentation region.

[0102] A48、Each basic region and the corresponding new segmentation region of each basic region form a temperature control region.

[0103] Please refer to Figure 4 The specific process of A47 step of further segmentation according to the preset segmentation rule is as follows: A471、Identify the three-dimensional profile of the basic region to obtain the number of deformation points and the positions of each deformation point.

[0104] A472、If the number of deformation points is less than or equal to the preset deformation point number threshold, no new segmentation is performed.

[0105] A473. If the number of deformation points is greater than the preset deformation point threshold, calculate the distance between each adjacent deformation point. If the maximum distance is less than or equal to the preset distance threshold, no new segmentation is performed.

[0106] A474. If the distance between adjacent deformation points is greater than a preset distance threshold, then the center position between the adjacent deformation points is used as the dividing position, and a dividing line is generated along the normal direction of the dividing position to obtain the newly added dividing region.

[0107] It should be noted that when simulating the current heat distribution in each basic region, the structural parameters of the cavity, such as wall thickness, cavity spacing, geometry, and thermal performance parameters of the injection molding material, such as thermal conductivity and specific heat capacity, can be input first. Based on Fourier's law and the principle of energy conservation, a three-dimensional heat transfer model can be constructed. The mold can be divided into several basic region grids using Moldflow simulation software. After setting the initial temperature and boundary conditions, the energy changes of each grid unit under heat conduction, convection, and radiation are iteratively calculated, and finally the temperature values ​​of each basic region are output.

[0108] The initial temperature can be set to room temperature or the residual temperature at the end of the previous process. The boundary conditions include the heating or cooling power of the cavity and the heat exchange coefficient with the outside world. The boundary conditions can be set and adjusted according to the actual production needs of automotive parts. The Moldflow simulation software is all existing technology and will not be shown or described in detail in this invention.

[0109] It should be noted that the aforementioned preset deformation point threshold is the critical value for determining whether the basic region needs to be further subdivided based on deformation points. Its setting can be based on the deformation complexity of the three-dimensional contour of the basic region, combined with the temperature control accuracy to comprehensively determine the effectiveness of temperature control in a single region. The specific value can be selected based on the contour complexity level. The contour complexity level is inversely proportional to the preset deformation point threshold value. For example, when the contour complexity level is low, such as a planar cavity region, the value is 10; when the contour complexity level is medium, such as a cavity region containing simple curvatures, the value is 7; and when the contour complexity level is high, such as a cavity region with multiple intersecting curved surfaces, the value is 3.

[0110] Understandably, the aforementioned preset distance threshold is the critical distance value for determining whether adjacent deformation points need to be separated. When the distance between adjacent deformation points exceeds this threshold, a dividing line needs to be generated with the center of the two points as the dividing position.

[0111] It should be pointed out that the above-mentioned preset distance threshold is determined by comprehensively considering the influence of the spatial distribution of adjacent deformation points in the basic region on the temperature control uniformity, in combination with the region size and the temperature control precision requirement. By analyzing the correlation between the distance between adjacent deformation points in the historical segmentation case and the temperature regulation effect, the maximum allowed distance that can ensure the temperature control consistency in the same region can be taken as the preset distance threshold, so as to ensure that the adjacent deformation points with a distance greater than the threshold need to be segmented to avoid temperature control inconsistency caused by too far distance.

[0112] The embodiment of the present application adjusts the temperature control region from three dimensions of temperature difference, wall thickness difference and regularity by combining the structural characteristics of the mold cavity and the properties of the injection molding material. When any dimension exceeds the preset threshold, the region segmentation is automatically started to avoid the lack of pertinence in the current temperature control region division, so as to closely associate the temperature control region segmentation with the product quality, thereby having clear pertinence and ensuring the injection molding quality.

[0113] S5. Obtain a matched temperature adjustment strategy by matching a preset temperature control model according to the current temperature of each temperature control region and the properties of the injection molding material, the properties of the mold material and the planned cooling time, and execute cooling regulation according to the temperature adjustment strategy.

[0114] It should be noted that the above-mentioned preset temperature control model is a preset temperature control strategy table according to the injection molding process parameter specification. The preset temperature control strategy table is formed by collecting a large amount of cooling regulation data under the combination of parameters such as current temperature of different temperature control regions, properties of injection molding material and mold material, planned cooling time, combining heat conduction simulation and actual production verification, analyzing the influence law of each parameter on temperature adjustment, associating effective temperature adjustment strategies such as cooling rate and spray intensity with corresponding parameter combinations, and forming a structured table after repeated optimization iteration. The structured table is the preset temperature control model.

[0115] The above formulas are dimensionless values calculated. The formulas are obtained by collecting a large amount of data to simulate the most real situation. The preset parameters in the formulas are set by a person skilled in the art according to the actual situation.

[0116] The above content is only an example and description of the concept of the present application. Those skilled in the art can make various modifications or supplements to the described specific embodiments or use similar ways to replace them, as long as they do not deviate from the concept of the present application or exceed the scope defined by the present application.

Claims

1. A method of controlling the temperature of a region of a mold for an automotive part, characterized by, The method comprises: generating a thermal image by detecting the overall cavity of the mold by a thermal imager, and identifying the thermal image to obtain temperature information; screening cavity positions that do not meet the injection preheating requirements based on the temperature information, and starting the temperature control unit in the positions to perform corresponding temperature regulation until the injection preheating requirements are met and then performing injection; collecting the temperature value of the cavity after injection of the molten injection material in real time through the temperature sensor built in the mold, determining the temperature regulation cavity position according to the current temperature value collected by the temperature sensor and the distribution position and the overall cavity three-dimensional space position coordinates, and performing corresponding cavity temperature regulation; after completing the injection and ending the pressure maintaining process, dividing the overall cavity into a plurality of temperature control regions according to the structure characteristics of the overall cavity, and collecting the current temperature according to the temperature sensor built in each temperature control region; obtaining a matched temperature adjustment strategy according to the current temperature of each temperature control region, the injection material characteristics, the mold material characteristics and the planned cooling time, and performing cooling regulation according to the temperature adjustment strategy; the specific steps of performing corresponding cavity temperature regulation are as follows: taking the difference between the current temperature value of the temperature regulation cavity position and the preset injection threshold value as a preliminary cavity regulation temperature value; calculating a target cavity regulation temperature value according to the preliminary cavity regulation temperature value, the wall thickness of the temperature regulation cavity position and the cavity material characteristics; and starting the temperature control unit of the regulation cavity position to perform cavity temperature regulation according to the corresponding target regulation temperature value of the position; the division method of the temperature control region comprises: marking each key node in the three-dimensional model of the overall cavity, taking the key node as a segmentation endpoint, taking the connecting line of the region where the key node is located as a segmentation line, and dividing the overall cavity into a plurality of basic regions; simulating the current heat distribution of each basic region based on the structure parameters of the cavity and the thermal conductivity and specific heat capacity of the injection material, obtaining the maximum temperature difference and the average temperature value of the basic region according to the heat distribution; extracting the three-dimensional profile of each basic region, identifying the wall thickness of each cavity position point in the corresponding basic region based on the three-dimensional profile, counting the average cavity wall thickness of each basic region, and extracting the maximum wall thickness; adjusting the basic region based on the maximum temperature difference, the average temperature value, the three-dimensional profile, the average cavity wall thickness and the maximum wall thickness of each basic region, and the wall thickness of each cavity position point in each basic region, and outputting the final each temperature control region.

2. A method of controlling the temperature of a region of a mould for an automotive component as claimed in claim 1, characterised in that: The process of obtaining the temperature information comprises: establishing the mapping relationship between the thermal image pixels and the overall cavity three-dimensional space position coordinates by SIFT algorithm after distortion correction of the thermal image by importing the three-dimensional model of the overall cavity; identifying the thermal image to obtain each temperature region and the temperature value of the corresponding temperature region, and marking the cavity position to which each temperature region belongs; composing the temperature value corresponding to each temperature region and the cavity position belonging to the temperature value into temperature information.

3. A method of controlling the temperature of a region of a mould for an automotive component as claimed in claim 2, wherein: The step of screening the cavity positions that do not meet the injection preheating requirements comprises: matching the preset preheating standard temperature value of the corresponding temperature region based on the cavity position belonging to each temperature region; comparing the temperature value corresponding to each temperature region with the preset preheating standard temperature value thereof; If the temperature value of a temperature region is lower than the preset preheating standard temperature value and the difference between the temperature value and the preset preheating standard temperature value exceeds the preset permitted range, the temperature region is marked as a cavity position that does not meet the injection preheating requirement.

4. A method of controlling the temperature of a region of a mold for an automotive part as defined in claim 1, wherein: The step of performing corresponding temperature regulation comprises: Marking the cavity positions that do not meet the injection preheating requirement as regulation positions, and counting the number of the regulation positions; When there is only one regulation position, taking the difference between the corresponding temperature value of the regulation position and the preset preheating standard temperature value as a regulation temperature value, and starting the temperature control unit in the regulation position to execute a heating instruction based on the regulation temperature value; When there are more than one regulation positions, counting the distances between the regulation positions; If the maximum distance does not exceed the preset interval distance and the standard deviation of the regulation temperature values of the regulation positions is less than the preset threshold value, connecting the regulation positions to generate an overall regulation region; Taking the average regulation temperature value of the regulation positions as the regulation temperature value of the overall regulation region, and starting the temperature control unit in the overall regulation region to perform heating based on the regulation temperature value; If the distance between adjacent regulation positions exceeds the preset interval distance or the distance between the adjacent regulation positions does not exceed the preset interval distance and the difference between the regulation temperature values of the adjacent regulation positions exceeds the preset adjacent regulation temperature difference, starting the temperature control unit in the adjacent regulation positions to perform heating based on the regulation temperature values respectively; Traversing all adjacent regulation positions, marking adjacent regulation positions with a distance less than the preset interval distance as bound, and grouping all adjacent regulation positions with continuous bound marking into an overall regulation group; Taking the average regulation temperature value of the cavity positions in the overall regulation group as the regulation temperature value of the overall regulation group, and starting the temperature control unit of the overall regulation group to execute a heating instruction based on the regulation temperature value.

5. A method of controlling the temperature of a region of a mold for an automotive part as defined in claim 2, wherein: The determination method of the temperature regulation cavity position comprises: Comparing the distribution positions of the temperature sensors with the overall cavity three-dimensional space position coordinates to obtain the mapping cavity positions of the temperature sensors; Matching the preset injection threshold value corresponding to the mapping cavity position of each temperature sensor based on the mapping cavity position of each temperature sensor; Comparing the current temperature value collected by each temperature sensor with the preset injection threshold value of the mapping cavity position thereof; If the current temperature value collected by a temperature sensor is lower than the preset injection threshold value of the mapping cavity position thereof and the difference between the current temperature value and the preset injection threshold value exceeds the preset permitted range, marking the mapping cavity position of the temperature sensor as a temperature regulation cavity position.

6. A method of controlling the temperature of a region of a mould for an automotive component as claimed in claim 5, characterised in that: The calculation process of the target cavity regulation temperature value comprises: Calculating a comprehensive compensation coefficient according to the cavity wall thickness and the material thermal characteristics; Correcting the preliminary cavity regulation temperature value to obtain the target cavity regulation temperature value according to the comprehensive compensation coefficient.

7. A method of controlling the temperature of a region of a mould for an automotive component as claimed in claim 6, characterised in that: The process of adjusting the basic regions comprises: Identifying the three-dimensional profile of each basic region to obtain the regularity of each basic region; Judging whether each basic region triggers any of the following conditions, if yes, starting a basic region adjustment instruction, otherwise, not executing the basic region adjustment; (1) the maximum temperature difference is greater than the preset temperature difference; (2) the difference between the maximum wall thickness and the average cavity wall thickness exceeds the preset wall thickness difference; (3) the regularity is lower than the preset high regularity threshold value; When a basic region triggers a maximum temperature difference greater than a preset temperature difference, temperature values of each heat distribution region are obtained based on heat distribution, an absolute difference value between the temperature values of each heat distribution region and an average temperature of the basic region is calculated, and a heat distribution region with an absolute difference value exceeding the preset temperature difference value is taken as a new segmentation region; When a basic region triggers a maximum wall thickness and an average cavity wall thickness difference exceeding a preset wall thickness difference, if a wall thickness of any cavity position deviates from the average cavity wall thickness of the basic region by an absolute value exceeding the preset wall thickness difference, the cavity position is taken as a new segmentation point, a segmentation boundary is generated along the new segmentation point, and a new segmentation region is obtained; When a basic region triggers a regularity lower than a preset high regularity threshold, if the regularity in the basic region is less than the set low regularity threshold, a curvature mutation point of a three-dimensional profile corresponding to the basic region is identified and taken as a new segmentation point, a segmentation boundary is generated along the new segmentation point, and a new segmentation region is obtained; If the regularity in the basic region is greater than the set low regularity threshold and less than the set high regularity threshold, the basic region is segmented again according to a preset segmentation rule to obtain a new segmentation region; Each basic region and the new segmentation region corresponding to each basic region form a temperature control region.

8. A method of controlling the temperature of a region of a mould for an automotive component as claimed in claim 7, characterised in that: The specific process of the preset segmentation rule is as follows: Identify the three-dimensional profile of the basic region to obtain the number of deformation points and the positions of the deformation points; If the number of deformation points is less than or equal to a preset deformation point number threshold, no new segmentation is performed; If the number of deformation points is greater than the preset deformation point number threshold, the distance between each adjacent deformation point is calculated, and if the maximum distance is less than or equal to a preset distance threshold, no new segmentation is performed; If there is a distance between adjacent deformation points greater than the preset distance threshold, the center position between the adjacent deformation points is taken as a segmentation position, a segmentation boundary is generated in the normal direction of the segmentation position, and a new segmentation region is obtained.

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