Mold preheating method

Abstract

The invention relates to a mold preheating method. The mold preheating method comprises the following steps that S10, a molded surface of a mold is obtained through laser scanning, and a scanning model is established; s20, according to the scanning model, dividing hot area sensitivity grades; s30, a preheating strategy of the mold is preset according to the hot areas with the different grades of thermal sensitivities; s40, after the mold is preheated according to the preheating strategy, temperature field distribution is updated every preset interval; and S50, according to the newest temperature field distribution, preheating parameters of the mold are adjusted. The method is beneficial to eliminating a preheating blind area and an overheat area, precise preheating of the complex-surface mold is achieved, the mindset of extensive and uniform heating in traditional preheating is broken through, the problems of heat efficiency, uniformity, thermal stress and the like in preheating of the complex-surface mold are fundamentally solved, and then the service life of the mold is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of molds, and particularly to a method for preheating a mold. Background Art

[0002] In the modern industrial manufacturing system, as a basic process equipment for industrial production, molds are widely used in multiple fields such as automobiles, electronics, aerospace, and medical devices. Their quality and performance directly determine the accuracy, quality, and production efficiency of products, and play a crucial role in promoting the high-quality development of the manufacturing industry.

[0003] With the rapid development of the manufacturing industry, the structure and function of products are becoming increasingly complex, posing higher requirements for the accuracy, lifespan, and reliability of molds. The contour structure of molds has gradually evolved from simple planes and regular curved surfaces to complex structures containing a large number of free-form surfaces, micro features, and complex cavities. For example, in automobile manufacturing, the body panel molds need to accurately form complex curved surface shapes to meet the requirements of the automobile appearance and aerodynamics; the molds for 3C products need to machine precise card slots, holes, and other structures in a very small space.

[0004] At present, traditional mold preheating methods, such as resistance heating and steam heating, mostly adopt an overall heating mode and can only control the overall temperature of the mold. This rough heating method is difficult to adapt to the complex contour structure of the mold, resulting in inevitable preheating blind spots or overheating areas during the mold preheating process. When the mold is subjected to high-temperature shocks during subsequent processing, the heat is unevenly distributed in each area, and the expansion degrees of different parts are inconsistent, thus generating large thermal stresses. Once the thermal stress exceeds the strength limit of the mold material, the mold will undergo failure phenomena such as cracking and deformation, which not only shortens the service life of the mold, but also frequent mold repairs and replacements will lead to production interruptions, increase production costs, and reduce production efficiency. Therefore, how to solve the problems of low thermal efficiency, high energy consumption, poor uniformity, and thermal stress concentration during the mold preheating process has become a technical problem that urgently needs to be overcome to improve the performance of molds and promote the development of the mold industry. Summary of the Invention

[0005] Based on this, it is necessary to provide a method for preheating a mold, which can effectively improve the service life of the mold.

[0006] The technical solution is as follows: A method for preheating a mold, the mold preheating method includes the following steps: Laser scanning is used to obtain the surface of the mold to establish a scanning model; The thermal zone sensitivity level is divided according to the scanning model; For thermal zones with different levels of thermal sensitivity, a preheating strategy for the mold is preset; After preheating the mold according to the preheating strategy, the temperature field distribution is updated at each preset interval; Adjust the preheating parameters of the mold according to the latest temperature field distribution.

[0007] In one embodiment, the steps: laser scan to obtain the surface of the mold and establish a scanning model, specifically including: Use a laser scanning device to scan the surface of the mold; After scanning, obtain the three-dimensional coordinate data of the mold according to the scanning model; Calculate the surface curvature distribution of the mold.

[0008] In one embodiment, the steps: divide the thermal zone sensitivity levels according to the scanning model, specifically including: Divide the thermal zone sensitivity levels according to the curvature distribution, where: the area with curvature greater than the first preset value is divided into the first thermal zone, the area with curvature less than or equal to the first preset value and greater than the second preset value is divided into the second thermal zone, and the area with curvature less than or equal to the second preset value is divided into the third thermal zone.

[0009] In one embodiment, the difference between the first preset value and the second preset value is greater than the difference between the second preset value and the third preset value.

[0010] In one embodiment, the steps: preset the preheating strategy of the mold for thermal zones with different levels of thermal sensitivity, specifically including: Input the three-dimensional coordinate data and the thermal zone sensitivity level data into the preheating device; The preheating device preheats the first thermal zone, the second thermal zone, and the third thermal zone respectively according to the two types of data.

[0011] In one embodiment, in the preheating strategy, the preheating strategy for the first thermal zone is: use an infrared heating tube, cooperate with the first heating power and the first heating speed, and preheat the first thermal zone; The preheating strategy for the second thermal zone is: use the electromagnetic induction and infrared heating tube methods, both cooperate with the second heating power and the second heating speed, and preheat the second thermal zone; The preheating strategy for the third thermal zone is: use a resistance heating furnace to preheat the third thermal zone with the third heating power and the third heating speed; Among them, the ratio of the second heating power to the first heating power is 5 - 10, and the ratio of the third heating power to the first heating power is 6 - 15; the ratio of the second heating speed to the first heating speed is 3 - 10, and the ratio of the third heating speed to the first heating speed is 5 - 12.

[0012] In one embodiment, in the first thermal zone, along the contour area of the first thermal zone according to the three-dimensional coordinate data, use a robot to control the infrared heating pipeline to move in a scanning manner; In the second heating zone, along the contour area of the second heating zone according to the three-dimensional coordinate data, the robot is used to control the infrared heating pipeline to move in a scanning manner; The resistance heating furnace is correspondingly arranged with the third heating zone.

[0013] In one embodiment, the step: after preheating the mold according to the preheating strategy, updating the temperature field distribution at each preset interval specifically includes: Preheat the mold according to the preheating strategy for 30 seconds; After preheating, use the thermal imaging device to perform thermal imaging on the mold surface every 5 - 10 seconds to update the temperature field distribution.

[0014] In one embodiment, the step: adjusting the preheating parameters of the mold according to the latest temperature field distribution specifically includes: According to the latest temperature field, adjust the heating power of the corresponding heating zone. Among them, when the average temperature of the first heating zone is less than that of the second heating zone, the first heating power increases by 20%; when the average temperature of the first heating zone is greater than or equal to the average temperature of the second heating zone, the second heating power increases by 20%; when the average temperature of the first heating zone is less than the average temperature of the third heating zone, the first heating power increases by 40%; when the average temperature of the first heating zone is greater than or equal to the average temperature of the third heating zone, the third heating power increases by 40%, until all heating zones are preheated to the specified temperature.

[0015] In one embodiment, the specified temperature of the first heating zone is the first specified temperature T1, the specified temperature of the second heating zone is the second specified temperature T2, and the specified temperature of the third heating zone is the third specified temperature T3, and the following relationship is satisfied among the first specified temperature T1, the second specified temperature T2, and the third specified temperature T3: T n / T （n+1） =m(K n / K （n+1） )+C*α; where T n is the nth specified temperature, K n is the curvature of the nth heating zone, n≥1 and n is a positive integer, 1<m≤15, C is a constant, and α is an environmental correction factor and is a constant.

[0016] In one embodiment, when any heating zone reaches the specified temperature, the preheating strategy jumps to the heat preservation mode.

[0017] In the above mold preheating method, during the use process, through the closed-loop control logic of "data-driven - zone control - dynamic feedback", zone control and dynamic adjustment are carried out. A laser scanning device is used to obtain the three-dimensional coordinates of the mold surface, and a digital model is constructed, providing a geometric basis for subsequent heat zone analysis. Based on the curvature distribution of the model, the mold is divided into different heat sensitivity zones, and the key parts prone to thermal stress are identified. Exclusive heating schemes are formulated for the characteristics of each heat zone, and parameters such as heating equipment, power, and speed are matched. Finally, the temperature distribution is monitored in real time through thermal imaging, and the heating parameters are dynamically corrected according to the feedback data, forming a "measurement - control - optimization" cycle. The above preheating method is beneficial to eliminating preheating blind spots and overheating zones, realizing precise preheating of complex-shaped surface molds, breaking through the traditional thinking mode of "coarse and uniform heating" in preheating, establishing an intelligent preheating system of "precise identification - zone-based measures - real-time correction", avoiding uneven heating of each region and inconsistent expansion degrees of different parts when the mold is subjected to high-temperature impact during the preheating process, thus avoiding failure phenomena such as cracking and deformation, and being beneficial to fundamentally solving problems such as thermal efficiency, uniformity, and thermal stress in the preheating of complex-shaped surface molds, and then improving the service life of the mold. In addition, it can also reduce the frequency of mold repair and replacement, lower production costs, and ensure production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0020] Figure 1 It is a flowchart of the steps of the mold preheating method in an embodiment.

[0021] Figure 2 It is a detailed flowchart of the specific steps of step S10 in an embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] In order to make the above objects, features, and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention will be described in detail below with reference to the drawings. Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein. Those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0023] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation on the present invention.

[0024] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0025] In the present invention, unless otherwise clearly specified and limited, the terms "mounted", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] In the present invention, unless otherwise clearly specified and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0027] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are only for illustrative purposes and do not represent the only implementation.

[0028] Refer to Figure 1 , Figure 1 which shows the step flow chart of the mold preheating method in an embodiment of the present invention. An embodiment of the present invention provides a mold preheating method, and the mold preheating method includes the following steps: S10: Laser scan to obtain the surface of the mold and establish a scan model; S20: Divide the heat zone sensitivity levels according to the scan model; S30: Preset the preheating strategy for the heat zones with different heat sensitivities; S40: After preheating the mold according to the preheating strategy, update the temperature field distribution at each preset interval; S50: Adjust the preheating parameters of the mold according to the latest temperature field distribution.

[0029] In the above mold preheating method, during use, through the closed-loop control logic of "data-driven - zone control - dynamic feedback", zone control and dynamic adjustment are carried out. The three-dimensional coordinates of the mold surface are obtained by using a laser scanning device to construct a digital model, providing a geometric basis for subsequent heat zone analysis. Based on the model curvature distribution, the mold is divided into different heat sensitivity regions to identify the key parts prone to thermal stress. Exclusive heating schemes are formulated for the characteristics of each heat zone, and parameters such as heating equipment, power, and speed are matched. Finally, the temperature distribution is monitored in real time by thermal imaging, and the heating parameters are dynamically corrected according to the feedback data to form a "measurement - control - optimization" cycle. The above preheating method is beneficial to eliminating the preheating blind area and overheating area, realizing precise preheating of complex surface molds, breaking through the traditional preheating thinking mode of "extensive and uniform heating", establishing an intelligent preheating system of "precise identification - zone-based measures - real-time correction", avoiding uneven heating of each region and inconsistent expansion degrees of different parts when the mold is subjected to high-temperature impact during the preheating process, thus avoiding failure phenomena such as cracking and deformation, and being beneficial to fundamentally solving problems such as thermal efficiency, uniformity, and thermal stress in the preheating of complex surface molds, and then improving the service life of the mold. In addition, it can also reduce the frequency of mold repair and replacement, lower production costs, and ensure production efficiency.

[0030] In one embodiment, please refer to Figure 2 , step S10: Laser scan to obtain the surface of the mold and establish a scan model, specifically including: S11: Scan the surface of the mold using a laser scanning device; S12: After scanning, obtain the three-dimensional coordinate data of the mold based on the scanned model; S13: Calculate the curvature distribution of the mold surface.

[0031] Use a laser scanning device to emit a laser beam, receive the reflected light from the mold surface, and obtain the three-dimensional coordinate data of each point on the mold surface based on the principle of triangulation or time-of-flight method. Then, calculate the curvature distribution of the surface through a professional algorithm. The three-dimensional coordinate data provides accurate position information for subsequent heat zone division and heating path planning, while the curvature distribution intuitively reflects the complexity and thermal sensitivity characteristics of the surface. The accurate calculation of three-dimensional coordinate data and curvature distribution provides a scientific and accurate basis for heat zone division, which is conducive to improving the recognition accuracy of thermally sensitive areas such as sharp corners and narrow grooves on the mold, and further conducive to the accuracy of formulating subsequent targeted preheating strategies, avoiding poor preheating effects caused by misjudgment of heat zones.

[0032] Among them, the laser scanning device can be Keyence's full-automatic scanning 3D vision system, Micro-Epsilon's ScanCONTROL laser scanner, Hexagon's HyperScan intelligent optical tracking 3D scanner, or other scanning devices. By means of the principle of triangulation, time-of-flight method, etc., emit a laser beam and receive the reflected light to collect the three-dimensional coordinate data of a large number of discrete points on the mold surface, forming point cloud data. Subsequently, professional three-dimensional modeling and analysis software is required to process the point cloud data. The software first performs preprocessing such as denoising, thinning, and stitching on the original point cloud to improve the data quality and integrity. Then, using surface reconstruction algorithms, the point cloud data is fitted into a continuous surface model. Common algorithms include triangular meshing, NURBS (Non-Uniform Rational B-Spline) surface fitting, etc. After constructing the surface model, the software calculates the curvature based on the principles of differential geometry. For example, in discrete data, by fitting local surface patches and using the derivative of the mathematical expression of the surface patch to estimate the curvature; for a parametric surface model, the Gaussian curvature, mean curvature, etc. can be calculated directly based on its mathematical expression through analytical or numerical differentiation. Finally, through calculation and analysis, the curvature distribution of each region of the mold surface is output, providing a key basis for dividing the sensitivity level of heat zones.

[0033] Furthermore, the shooting speed of the laser scanning device is at most 0.2 s, and the repeatability accuracy is 0.3 μm. This can further ensure the scanning accuracy of the mold surface, thereby improving the accuracy of the preheating strategy.

[0034] In one embodiment, step S20: Divide the sensitivity level of heat zones according to the scanned model, specifically including: S21: Divide the sensitivity levels of the hot zones according to the curvature distribution, where: the area with a curvature greater than the first preset value is divided into the first hot zone, the area with a curvature less than or equal to the first preset value and greater than the second preset value is divided into the second hot zone, and the area with a curvature less than or equal to the second preset value is divided into the third hot zone.

[0035] Set two thresholds (the first preset value, the second preset value) according to the curvature degree of the die surface, and divide the die into three hot zones. In the area with a large curvature, the heat conduction and distribution are complex, and thermal stress is likely to occur, which is divided into the first hot zone with high sensitivity; the area with a medium curvature is the second hot zone; the area with a small curvature has good thermal stability and is divided into the third hot zone with low sensitivity. This division method is closely related to the thermophysical properties of the die and can effectively match the preheating requirements of different areas. A reasonable hot zone division realizes the differential preheating of the die. Different preheating strategies are adopted for different hot zones, so that the highly sensitive areas are fully and accurately heated, reducing the risk of thermal stress; the medium-sensitive areas avoid overheating or insufficient heating; the low-sensitive areas reduce energy waste. Compared with the traditional single preheating method, it can reduce energy consumption and improve the preheating quality and consistency of the die at the same time.

[0036] Furthermore, it is also possible to set the third preset value, the fourth preset value, the fifth preset value, etc. according to the size and curvature distribution of the die surface, and then divide more sensitivity levels of the hot zones.

[0037] In one embodiment, the difference between the first preset value and the second preset value is greater than the difference between the second preset value and the third preset value.

[0038] The larger difference between the first preset value and the second preset value means that the division of the high-sensitivity hot zone is more strict and detailed, and it can more accurately capture the areas on the die with drastic curvature changes and high thermal risks; while the smaller difference between the second preset value and the third preset value ensures a reasonable distinction between the medium-sensitive area and the low-sensitive area, ensuring that the division of different hot zones conforms to the actual thermal characteristic distribution law of the die. This threshold setting method makes the hot zone division more in line with the actual thermal sensitivity characteristics of the die, especially the identification of high-risk areas is more accurate. It can accurately divide the high-risk hot zones in more areas on the complex die into the first hot zone, avoiding overheating or underheating caused by fuzzy hot zone division, and further improving the effectiveness and reliability of die preheating.

[0039] In one embodiment, step S30: Preset the preheating strategy of the die for hot zones with different levels of thermal sensitivity, specifically including: S31: Input the three-dimensional coordinate data and the hot zone sensitivity level data into the preheating device; S32: The preheating device preheats the first hot zone, the second hot zone, and the third hot zone respectively according to the two types of data.

[0040] Input three-dimensional coordinate data and hot zone sensitivity level data into the preheating device. The preheating device determines the positions and preheating requirements of each hot zone of the mold based on this data, and then calls the corresponding heating equipment and control program to execute the preset preheating strategies for the first hot zone, the second hot zone, and the third hot zone respectively, realizing parallel and differential preheating operations for multiple hot zones, which is beneficial to achieving automatic and precise preheating of multiple hot zones of the mold. By driving the preheating device with data, manual intervention and operation errors are reduced, making the preheating process more efficient and stable. It can improve the automation degree of mold preheating, and at the same time ensure that each hot zone is precisely heated according to the predetermined strategy, improving the preheating quality and production efficiency.

[0041] In one embodiment, in the preheating strategy, the preheating strategy for the first hot zone is: using infrared heating tubes, in combination with the first heating power and the first heating speed, to preheat the first hot zone. The preheating strategy for the second hot zone is: using the electromagnetic induction and infrared heating tube methods, both in combination with the second heating power and the second heating speed, to preheat the second hot zone. The preheating strategy for the third hot zone is: using an electric resistance heating furnace at the third heating power and the third heating speed to preheat the third hot zone. Among them, the ratio of the second heating power to the first heating power is 5 to 10, and the ratio of the third heating power to the first heating power is 6 to 15. The ratio of the second heating speed to the first heating speed is 3 to 10, and the ratio of the third heating speed to the first heating speed is 5 to 12.

[0042] Optionally, the ratio of the second heating power to the first heating power is 5, 6, 7, 8, 9, 10 or any value in between; the ratio of the third heating power to the first heating power is 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or any value in between. The ratio of the second heating speed to the first heating speed is 3, 4, 5, 6, 7, 8, 9, 10 or any value in between; the ratio of the third heating speed to the first heating speed is 5, 6, 7, 8, 9, 10, 11, 12 or any value in between.

[0043] The first heating zone uses infrared heating tubes. Due to its fast heating speed and good directivity, combined with a high first heating power and first heating speed, it can quickly perform directional heating on the highly sensitive area, compensating for the problem of easy heat loss in this area. The second heating zone combines electromagnetic induction and infrared heating tubes. Electromagnetic induction achieves overall uniform heating, and the infrared heating tubes assist in fine-tuning for local areas. The medium second heating power and second heating speed ensure a uniform increase in temperature. The third heating zone uses a resistance heating furnace to perform overall heating at a lower third heating power and third heating speed to maintain a stable temperature. The specific ratio relationship of the heating power and speed in each heating zone ensures that the heating intensity of different heating zones matches the thermal sensitivity. In this way, different heating methods and parameter combinations are optimized according to the characteristics of each heating zone, which is beneficial to significantly improving the preheating effect. The rapid directional heating of the highly sensitive area can improve the temperature uniformity of this area. The combined heating of the moderately sensitive area ensures the overall temperature consistency. The energy-saving heating of the low-sensitivity area reduces energy consumption. Generally speaking, it is beneficial to improve the overall thermal efficiency of the mold and at the same time reduce the probability of mold damage caused by thermal stress.

[0044] In one embodiment, in the first heating zone, according to the three-dimensional coordinate data along the contour area of the first heating zone, a robot is used to control the infrared heating pipeline to move in a scanning manner. In the second heating zone, according to the three-dimensional coordinate data along the contour area of the second heating zone, a robot is used to control the infrared heating pipeline to move in a scanning manner. The resistance heating furnace is correspondingly arranged with the third heating zone.

[0045] In the first heating zone and the second heating zone, the robot controls the infrared heating pipeline to scan and move along the contour of the heating zone, so that the heating area fits precisely with the complex surface of the mold, realizing full coverage heating of the heating zone. The resistance heating furnace is correspondingly arranged with the third heating zone to perform overall uniform heating on the low-sensitivity area, ensuring that the heating method of each heating zone can fully adapt to its shape and thermal characteristics. The precise planning of the heating path effectively solves the heating problem of complex surface molds. The robot controls the infrared heating pipeline to scan and move, so that the heating coverage rate of the complex heating zone reaches more than 98%, avoiding the heating blind area under the traditional fixed heating method. The stable heating of the low-sensitivity area by the resistance heating furnace ensures the overall temperature balance of the mold, further improving the preheating quality and consistency of the mold.

[0046] Furthermore, multiple resistance heating furnaces are arranged in one-to-one correspondence with the third heating zone. In this way, the heating efficiency and uniformity of the third heating zone can be further improved.

[0047] In one embodiment, step S40: After preheating the mold according to the preheating strategy, update the temperature field distribution at each preset interval, which specifically includes: S41: Preheat the mold according to the preheating strategy for 30 seconds; S42: After preheating, use a thermal imaging device to perform thermal imaging on the die surface every 5 - 10 seconds to update the temperature field distribution.

[0048] First, preheat the die for 30 seconds according to the preheating strategy to initially raise the temperature of the die and reach a certain temperature base. Subsequently, use a thermal imaging device to perform thermal imaging on the die surface every 5 - 10 seconds, collect the temperature data of the die surface in real - time, update the temperature field distribution through data processing and analysis, and provide real - time and accurate temperature information for subsequent preheating parameter adjustment. A reasonable preheating time and temperature acquisition interval ensure the effectiveness and timeliness of the temperature field data. It can quickly capture the temperature change trend during the die preheating process, promptly detect hot and cold spots, shorten the response time for preheating parameter adjustment to within 10 seconds, effectively avoid thermal stress problems caused by the accumulation of temperature deviation, and improve the dynamic control accuracy and stability of die preheating.

[0049] Optionally, the thermal imaging device can be the Arctis M620 Tianxuan handheld infrared thermal imager, FOTRIC 280 series infrared thermal imager, Uni - Trend UTi640Q high - performance infrared thermal imager, testo thermal imager series, Gewoo Optoelectronics full - frame thermal imager, Guide Infrared H series intelligent infrared thermal imager, Marposs TTV panoramic thermal imager, or other instrument devices that can meet the requirements of thermal imaging.

[0050] In one embodiment, in step S50: Adjust the preheating parameters of the die according to the latest temperature field distribution, specifically including: S51: Adjust the heating power of the corresponding hot zone according to the latest temperature field. When the average temperature of the first hot zone is less than that of the second hot zone, the first heating power is increased by 20%. When the average temperature of the first hot zone is greater than or equal to the average temperature of the second hot zone, the second heating power is increased by 20%. When the average temperature of the first hot zone is less than the average temperature of the third hot zone, the first heating power is increased by 40%. When the average temperature of the first hot zone is greater than or equal to the average temperature of the third hot zone, the third heating power is increased by 40%, until all hot zones are preheated to the specified temperature.

[0051] According to the updated temperature field distribution, compare the average temperatures of each hot zone. When the average temperature of the first hot zone is lower than that of the second hot zone, increase the heating power of the first hot zone by 20% to accelerate the heating rate in this area; otherwise, increase the heating power of the second hot zone. Similarly, after comparing the temperatures of the first hot zone and the third hot zone, adjust the heating power of the corresponding hot zone according to the rules. By continuously adjusting the heating power of each hot zone, the temperatures of all hot zones gradually reach the specified temperature, achieving the equilibrium of the overall temperature of the mold. This dynamic power adjustment mechanism based on the temperature field effectively solves the problem of uneven temperatures in each hot zone of the mold. The temperature difference between each hot zone of the mold can be controlled within ±5°C. Compared with the traditional fixed-power heating method, it significantly improves the temperature uniformity of the mold, reduces the degree of thermal stress concentration, and reduces the risk of deformation and cracking of the mold caused by temperature differences.

[0052] In one embodiment, the specified temperature of the first hot zone is the first specified temperature T1, the specified temperature of the second hot zone is the second specified temperature T2, and the specified temperature of the third hot zone is the third specified temperature T3, and the first specified temperature T1 is greater than the second specified temperature T2 which is greater than the third specified temperature T3.

[0053] By setting different preheating specified temperatures for different hot zones, heat compensation for different hot zones is achieved. High-curvature zones (such as the first hot zone) are mostly structures such as thin walls, narrow slots, and sharp corners of the mold. The surface area-to-volume ratio is large, and heat is easily dissipated quickly through air convection or the mold body during preheating, resulting in the actual temperature being lower than the target value. By setting T1 to be the highest, the thermal shock caused by the high-temperature metal slurry temperature can be compensated, and at the same time, the heat dissipation loss can be avoided. The insufficient material fluidity and temperature loss caused by low temperature can be avoided, thereby avoiding poor filling of the molten metal during die casting. The plastic deformation ability of the material is enhanced, and the tensile stress generated during shrinkage during forming can be released through high-temperature plastic flow, reducing stress cracking in the thin-wall area and at the same time reducing the filling defect rate. Low-curvature zones (such as the third hot zone) are mostly thick-wall and planar structures with a large heat capacity (low S / V), and obvious heat accumulation. Setting T3 to be the lowest can prevent softening or grain coarsening of the mold material caused by overheating, avoid pearlite spheroidization or carbide precipitation caused by long-term high-temperature heating, and at the same time reduce ineffective heat input, further reducing production costs.

[0054] Furthermore, the first specified temperature T1, the second specified temperature T2, and the third specified temperature T3 satisfy: T n / T （n+1） =m(K n / K （n+1） )+C*α; where T n is the nth specified temperature, K n is the curvature of the nth hot zone, n≥1 and n is a positive integer, 1<m≤15, C is a constant, and α is an environmental correction factor and is a constant. Specifically, in this embodiment, n = 1 or 2. For example, when n = 1, T nis T1, i.e., the first specified temperature, T n+1 is T2, i.e., the second specified temperature, K n is K1, i.e., the curvature of the first heat zone, K n+1 is K2, i.e., the curvature of the second heat zone, and the first specified temperature and the second specified temperature satisfy: T1 / T2 = m(K1 / K2)+C*α.

[0055] It should be noted that when the die surface is divided into more heat zones, such as the fourth heat zone, the fifth heat zone, the sixth heat zone or other numbers of heat zones, the above proportional relationship is also satisfied. That is, n is a positive integer greater than 2.

[0056] The C*α term can dynamically adjust the temperature reference according to the actual working conditions. For example, for die materials with high thermal conductivity (such as copper alloy dies, with a large α value), increasing C*α can overall increase the temperature of each heat zone, avoiding insufficient temperature due to rapid heat dissipation of the material; and when producing in a low-temperature environment, the preheating effect can also be enhanced by adjusting α to ensure a stable temperature gradient. By establishing the above proportional relationship, precise matching of heating parameters can be achieved, and precise temperature setting of the heat zones can be realized according to the proportional relationship of the curvatures, transforming the die preheating from experience-driven to data-driven, further implementing corresponding targeted preheating strategies for different dies, precisely heating to reduce energy consumption, and quickly changing the die to improve production efficiency.

[0057] In one embodiment, when any heat zone reaches the specified temperature of the corresponding heat zone, the preheating strategy jumps to the heat preservation mode.

[0058] When any heat zone reaches the specified temperature, the preheating strategy automatically jumps to the heat preservation mode. At this time, the heating device reduces the power or operates at a constant low power to maintain the temperature of this heat zone stable near the specified temperature, preventing the temperature from being too high or too low, and ensuring that the die is in a suitable temperature state during subsequent processing. The timely switching of the heat preservation mode effectively avoids the problems of die overheating or too rapid temperature drop. It can control the temperature fluctuation range within ±2°C after the die reaches the target temperature, ensure the stable performance of the die, extend the service life of the die, and at the same time reduce the product quality fluctuation caused by unstable temperature and improve the qualified rate of die-casting products.

[0059] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0060] The above embodiments merely illustrate several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A method for preheating a mold, characterized in that, The mold preheating method includes the following steps: Laser scanning is used to obtain the mold surface and establish a scanning model; Divide the sensitivity level of hot areas according to the scanning model; Preset mold preheating strategies for hot zones with different levels of thermal sensitivity; After preheating the mold according to the preheating strategy, the temperature field distribution is updated at every preset interval; Adjust the mold preheating parameters according to the latest temperature field distribution.

2. The method for preheating a mold according to claim 1, characterized in that, Steps: Laser scanning obtains the mold surface and establishes a scanning model, which includes: Use laser scanning equipment to scan the mold surface; After scanning, the three-dimensional coordinate data of the mold is obtained according to the scanned model; Calculate the curvature distribution of the mold surface.

3. The method for preheating a mold according to claim 2, characterized in that, Steps: Divide the sensitivity level of the hot zone according to the scan model, including: The sensitivity levels of the hot zones are divided according to the curvature distribution, wherein: the area with a curvature greater than a first preset value is divided into a first hot zone, the area with a curvature less than or equal to the first preset value and greater than a second preset value is divided into a second hot zone, and the area with a curvature less than or equal to the second preset value is divided into a third hot zone.

4. The method for preheating a mold according to claim 3, characterized in that, The difference between the first preset value and the second preset value is greater than the difference between the second preset value and the third preset value.

5. The method for preheating a mold according to claim 3, characterized in that, Steps: According to the hot zones with different levels of thermal sensitivity, preset the preheating strategy of the mold, including: The three-dimensional coordinate data and the hot zone sensitivity level data are input into the preheating device; The preheating device preheats the first heating zone, the second heating zone and the third heating zone respectively according to two types of data.

6. The method for preheating a mold according to claim 5, characterized in that, In the preheating strategy, the preheating strategy for the first hot zone is: using an infrared heating tube, in combination with a first heating power and a first heating speed, to preheat the first hot zone; The preheating strategy for the second hot zone is: using electromagnetic induction and infrared heating tubes, both with the second heating power and the second heating speed, to preheat the second hot zone; The preheating strategy for the third hot zone is: preheating the third hot zone with a third heating power and a third heating speed by using a resistance heating furnace; Among them, the ratio of the second heating power to the first heating power is 5~10, and the ratio of the third heating power to the first heating power is 6~15; the ratio of the second heating speed to the first heating speed is 3~10, and the ratio of the third heating speed to the first heating speed is 5~12.

7. The method for preheating a mold according to claim 5, characterized in that, In the first hot zone, according to the three-dimensional coordinate data, the infrared heating pipeline is moved in a scanning manner along the contour area of ​​the first hot zone by using a robot to control the infrared heating pipeline; In the second hot zone, according to the three-dimensional coordinate data, the infrared heating pipeline is moved in a scanning manner along the contour area of ​​the second hot zone by using a robot to control the infrared heating pipeline; The resistance heating furnace is arranged corresponding to the third hot zone.

8. The method for preheating a mold according to claim 6, characterized in that, Steps: After preheating the mold according to the preheating strategy, the temperature field distribution is updated at each preset interval, specifically including: Preheat the mold for 30 seconds according to the preheating strategy; After preheating, a thermal imaging device is used to take thermal images of the mold surface every 5 to 10 seconds to update the temperature field distribution.

9. The method for preheating a mold according to any one of claims 3-8, characterized in that, step: According to the latest temperature field distribution, adjust the mold preheating parameters, including: Adjust the heating power of the corresponding hot zone according to the latest temperature field. Among them, when the average temperature of the first hot zone is lower than that of the second hot zone, the first heating power is increased by 20%; when the average temperature of the first hot zone is greater than or equal to the average temperature of the second hot zone, the second heating power is increased by 20%; when the average temperature of the first hot zone is lower than the average temperature of the third hot zone, the first heating power is increased by 40%, and when the average temperature of the first hot zone is greater than or equal to the average temperature of the third hot zone, the third heating power is increased by 40%, until all hot zones are preheated to the specified temperature.

10. The method for preheating a mold according to claim 9, characterized in that,The specified temperature of the first hot zone is the first specified temperature T1, the specified temperature of the second hot zone is the second specified temperature T2, and the specified temperature of the third hot zone is the third specified temperature T3. And among the first specified temperature T1, the second specified temperature T2, and the third specified temperature T3, it satisfies: T n / T （n+1） =m(K n / K （n+1） )+C*α; where T n is the nth specified temperature, K n is the curvature of the nth hot zone, n≥1 and n is a positive integer, 1<m≤15, C is a constant, and α is an environmental correction factor and is a constant.

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