A mold preheating method

Abstract

The present invention relates to a mold preheating method, comprising the following steps: S10: laser scanning to obtain the mold surface and establish a scanning model; S20: dividing the hot zone sensitivity levels according to the scanning model; S30: presetting the mold preheating strategy for hot zones with different levels of thermal sensitivity; S40: after preheating the mold according to the preheating strategy, updating the temperature field distribution at preset intervals; S50: adjusting the mold preheating parameters based on the latest temperature field distribution. This method is conducive to eliminating preheating blind spots and overheating areas, achieving precise preheating of complex surface molds, breaking through the traditional preheating mindset of "extensive and uniform heating", and is conducive to fundamentally solving the problems of thermal efficiency, uniformity, thermal stress, etc. in the preheating of complex surface molds, thereby improving the service life of the mold.

Description

Technical Field

[0001] The present invention relates to the field of mold technology, in particular to a mold preheating method. Background Art

[0002] In modern industrial manufacturing, molds, as fundamental process equipment, are widely used in a variety of fields, including automotive, electronics, aerospace, and medical devices. Their quality and performance directly determine product precision, quality, and production efficiency, playing a vital role in promoting high-quality development in the manufacturing industry.

[0003] With the rapid development of the manufacturing industry, product structures and functions are becoming increasingly complex, placing higher demands on mold precision, lifespan, and reliability. Mold profiles have evolved from simple flat surfaces and regular curves to complex structures incorporating numerous freeform surfaces, tiny features, and complex cavities. For example, in automotive manufacturing, molds for body panels must precisely form complex curved shapes to meet both the vehicle's appearance and aerodynamic requirements. Molds for consumer electronics (3C) products must create precise slots, holes, and other structures within a very small space.

[0004] At present, traditional mold preheating methods, such as resistance heating and steam heating, mostly adopt an overall heating mode, which can only control the overall temperature of the mold. This extensive heating method is difficult to adapt to the complex contour structure of the mold, resulting in the inevitable preheating blind area or overheating area of the mold during the preheating process. When the mold is subjected to high temperature shock during subsequent processing, the various areas are heated unevenly, and the expansion degree of different parts is inconsistent, resulting in large thermal stress. Once the thermal stress exceeds the strength limit of the mold material, the mold will experience cracking, deformation and other failure phenomena, which not only shortens the service life of the mold, but frequent mold maintenance and replacement will also 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 in the mold preheating process has become a technical problem that needs to be overcome urgently to improve mold performance and promote the development of the mold industry. Summary of the Invention

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

[0006] The technical solution is as follows: A mold preheating method, the mold preheating method includes the following steps:

[0007] Laser scanning is used to obtain the mold surface and establish a scanning model;

[0008] Divide the sensitivity level of hot areas according to the scanning model;

[0009] Preset mold preheating strategies for hot zones with different levels of thermal sensitivity;

[0010] After preheating the mold according to the preheating strategy, the temperature field distribution is updated at every preset interval;

[0011] Adjust the mold preheating parameters according to the latest temperature field distribution.

[0012] In one embodiment, the step of obtaining the mold surface by laser scanning and establishing a scanning model specifically includes:

[0013] Use laser scanning equipment to scan the mold surface;

[0014] After scanning, the three-dimensional coordinate data of the mold is obtained according to the scanned model;

[0015] Calculate the mold surface curvature distribution.

[0016] In one embodiment, the step of classifying the sensitivity levels of the hot zones according to the scanning model specifically includes:

[0017] The sensitivity levels of hot zones are divided according to the curvature distribution, where 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.

[0018] 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.

[0019] In one embodiment, the step of presetting a mold preheating strategy for hot zones with different levels of thermal sensitivity specifically includes:

[0020] The three-dimensional coordinate data and the hot zone sensitivity level data are input into the preheating device;

[0021] The preheating device preheats the first hot zone, the second hot zone and the third hot zone respectively according to two types of data.

[0022] In one embodiment, in the preheating strategy, the preheating strategy for the first hot zone is: using an infrared heating tube, with a first heating power and a first heating speed, to preheat the first hot zone;

[0023] 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;

[0024] The preheating strategy for the third hot zone is: preheating the third hot zone with a resistance heating furnace at a third heating power and a third heating speed;

[0025] 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.

[0026] In one embodiment, in the first hot zone, the infrared heating pipeline is moved in a scanning manner along the contour area of the first hot zone according to the three-dimensional coordinate data using a robot;

[0027] 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 using a robot control;

[0028] The resistance heating furnace is arranged corresponding to the third hot zone.

[0029] In one embodiment, the step of preheating the mold according to the preheating strategy and updating the temperature field distribution at each preset interval specifically includes:

[0030] Preheat the mold for 30 seconds according to the preheating strategy;

[0031] 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.

[0032] In one embodiment, the step of adjusting the mold preheating parameters according to the latest temperature field distribution specifically includes:

[0033] According to the latest temperature field, the heating power of the corresponding hot zone is adjusted. 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%; 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.

[0034] In one embodiment, the designated temperature of the first thermal zone is a first designated temperature T1, the designated temperature of the second thermal zone is a second designated temperature T2, and the designated temperature of the third thermal zone is a third designated temperature T3, and the first designated temperature T1, the second designated temperature T2, and the third designated temperature T3 satisfy the following conditions: n / T （n+1） =m(K n / K （n+1） )+C*α; where T n is the nth specified temperature, K nis the curvature of the nth hot zone, n≥1, and n is a positive integer, 1<m≤15, C is a constant, α is the environmental correction factor and is also a constant.

[0035] In one embodiment, the preheating strategy switches to a keep warm mode when any thermal zone reaches a specified temperature.

[0036] During use, the above-mentioned mold preheating method adopts the closed-loop control logic of "data-driven-partition control-dynamic feedback", partition control and dynamic adjustment, uses laser scanning equipment to obtain the three-dimensional coordinates of the mold surface, and constructs a digital model to provide a geometric basis for subsequent hot zone analysis. Based on the model curvature distribution, the mold is divided into different thermal sensitivity areas, and the key parts prone to thermal stress are identified. Exclusive heating plans are formulated according to the characteristics of each hot zone, matching heating equipment, power, speed and other parameters. Finally, the temperature distribution is monitored in real time through thermal imaging, and the heating parameters are dynamically corrected based on the feedback data, forming a "measurement-control-optimization" cycle. This preheating method helps eliminate blind and overheating zones, enabling precise preheating of complex molds. It breaks through the traditional preheating paradigm of "extensive and uniform heating" and establishes an intelligent preheating system characterized by "precise identification, zoning, and real-time correction." This prevents uneven heating and inconsistent expansion of different parts of the mold when subjected to high temperatures during preheating, thus preventing failures such as cracking and deformation. This method fundamentally addresses issues such as thermal efficiency, uniformity, and thermal stress during preheating of complex molds, thereby extending the mold's service life. Furthermore, it reduces the frequency of mold repair and replacement, lowers production costs, and ensures production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 4 is a flowchart of the steps of a mold preheating method in one embodiment.

[0040] Figure 2 FIG. 1 is a flowchart of specific steps of step S10 in one embodiment. DETAILED DESCRIPTION

[0041] To make the above-mentioned objects, features, and advantages of the present invention more readily apparent, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. The following description sets forth numerous specific details to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0042] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are 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 therefore should not be understood as limiting the present invention.

[0043] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0044] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0045] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0046] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0047] See Figure 1 , Figure 1 A flowchart of a mold preheating method according to an embodiment of the present invention is shown. An embodiment of the present invention provides a mold preheating method, which includes the following steps:

[0048] S10: Laser scanning is used to obtain the mold surface and establish a scanning model;

[0049] S20: Divide the sensitivity level of hot zones according to the scanning model;

[0050] S30: Preset mold preheating strategy for hot zones with different levels of thermal sensitivity;

[0051] S40: After preheating the mold according to the preheating strategy, the temperature field distribution is updated at each preset interval;

[0052] S50: Adjust the mold preheating parameters according to the latest temperature field distribution.

[0053] During use, the above-mentioned mold preheating method adopts the closed-loop control logic of "data-driven-partition control-dynamic feedback", partition control and dynamic adjustment, uses laser scanning equipment to obtain the three-dimensional coordinates of the mold surface, and constructs a digital model to provide a geometric basis for subsequent hot zone analysis. Based on the model curvature distribution, the mold is divided into different thermal sensitivity areas, and the key parts prone to thermal stress are identified. Exclusive heating plans are formulated according to the characteristics of each hot zone, matching heating equipment, power, speed and other parameters. Finally, the temperature distribution is monitored in real time through thermal imaging, and the heating parameters are dynamically corrected based on the feedback data, forming a "measurement-control-optimization" cycle. This preheating method helps eliminate blind and overheating zones, enabling precise preheating of complex molds. It breaks through the traditional preheating paradigm of "extensive and uniform heating" and establishes an intelligent preheating system characterized by "precise identification, zoning, and real-time correction." This prevents uneven heating and inconsistent expansion of different parts of the mold when subjected to high temperatures during preheating, thus preventing failures such as cracking and deformation. This method fundamentally addresses issues such as thermal efficiency, uniformity, and thermal stress during preheating of complex molds, thereby extending the mold's service life. Furthermore, it reduces the frequency of mold repair and replacement, lowers production costs, and ensures production efficiency.

[0054] In one embodiment, see Figure 2 Step S10: Laser scanning to obtain the mold surface and establish a scanning model, specifically including:

[0055] S11: Scan the mold surface using a laser scanning device;

[0056] S12: After scanning, the three-dimensional coordinate data of the mold is obtained according to the scanned model;

[0057] S13: Calculate the curvature distribution of the mold surface.

[0058] Laser scanning equipment emits a laser beam, receives light reflected from the mold surface, and uses triangulation or time-of-flight methods to obtain the three-dimensional coordinate data of each point on the mold surface. The surface curvature distribution is then calculated using specialized algorithms. The three-dimensional coordinate data provides precise location information for subsequent hot zone delineation and heating path planning, while the curvature distribution intuitively reflects the complexity and thermal sensitivity of the mold surface. Accurate three-dimensional coordinate data and curvature distribution calculations provide a scientific and accurate basis for hot zone delineation, improving the accuracy of identifying heat-sensitive areas on the mold, such as sharp corners and narrow grooves. This in turn facilitates the precise development of subsequent targeted preheating strategies, avoiding poor preheating results due to misjudgment of hot zones.

[0059] Laser scanning equipment can include Keyence's fully automatic scanning 3D vision system, Micro-Epsilon's ScanCONTROL laser scanner, Hexagon's HyperScan intelligent optical tracking 3D scanner, or other scanning devices. Using triangulation principles and time-of-flight methods, laser beams are emitted and reflected light is received to collect 3D coordinate data for a large number of discrete points on the mold surface, forming point cloud data. Subsequently, the point cloud data is processed using professional 3D modeling and analysis software. The software first performs pre-processing on the raw point cloud, including denoising, streamlining, and splicing, to improve data quality and integrity. Next, surface reconstruction algorithms are used to fit the point cloud data into a continuous surface model. Commonly used algorithms include triangulation meshing and NURBS (non-uniform rational B-spline) surface fitting. After constructing the surface model, the software calculates curvature based on the principles of differential geometry. For example, for discrete data, curvature can be estimated by fitting local surface patches and then using the derivative of the patch's mathematical expression. For parametric surface models, Gaussian curvature, mean curvature, and other parameters can be calculated directly based on their mathematical expressions through analytical or numerical derivatives. Ultimately, calculations and analysis output the curvature distribution of each area on the mold surface, providing a key basis for grading hot zone sensitivity.

[0060] Furthermore, the laser scanning device has a maximum capture speed of 0.2s and a repeatability of 0.3μm. This further ensures the scanning accuracy of the mold surface, thereby improving the accuracy of the preheating strategy.

[0061] In one embodiment, step S20: classifying the sensitivity levels of the hot zones according to the scanning model, specifically includes:

[0062] S21: Divide the sensitivity levels of the hot zones 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.

[0063] Two thresholds (a first preset value and a second preset value) are set based on the degree of curvature of the mold surface, dividing the mold into three hot zones. Areas with large curvature have complex heat conduction and distribution, which are prone to thermal stress and are therefore classified as the highly sensitive first hot zone; areas with medium curvature are the second hot zone; and areas with small curvature have good thermal stability and are classified as the less sensitive third hot zone. This division method is closely linked to the thermophysical properties of the mold and can effectively match the preheating requirements of different areas. Reasonable hot zone division enables differentiated preheating of the mold. Different preheating strategies are adopted for different hot zones, ensuring that highly sensitive areas are fully and accurately heated, reducing the risk of thermal stress; overheating or underheating of moderately sensitive areas is avoided; and energy waste is reduced in low-sensitivity areas. Compared with traditional single preheating methods, this method reduces energy consumption while improving the quality and consistency of mold preheating.

[0064] Furthermore, a third preset value, a fourth preset value, a fifth preset value, etc. can be set according to the size and curvature distribution of the profile, thereby dividing more hot zone sensitivity levels.

[0065] 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.

[0066] A large difference between the first and second preset values means more rigorous and detailed delineation of high-sensitivity hot zones, enabling more accurate capture of areas on the mold with dramatic curvature changes and high thermal risk. A smaller difference between the second and third preset values ensures a reasonable distinction between medium- and low-sensitivity areas, ensuring that the division of different hot zones aligns with the mold's actual thermal distribution. This threshold setting approach ensures that hot zone division more closely matches the mold's actual thermal sensitivity, particularly accurately identifying high-risk areas. It can accurately assign high-risk hot zones in more complex molds to the first hot zone, avoiding over- or under-preheating due to ambiguous hot zone delineation and further improving the effectiveness and reliability of mold preheating.

[0067] In one embodiment, step S30: presetting a mold preheating strategy for hot zones with different levels of thermal sensitivity, specifically including:

[0068] S31: inputting the three-dimensional coordinate data and the hot zone sensitivity level data into the preheating device;

[0069] S32: The preheating device preheats the first heating zone, the second heating zone, and the third heating zone respectively according to the two types of data.

[0070] The preheating device inputs 3D coordinate data and hot zone sensitivity levels into the mold. Based on this data, the preheating device determines the location and preheating requirements of each mold hot zone. It then calls upon the corresponding heating equipment and control program to execute the preset preheating strategies for the first, second, and third hot zones, respectively. This enables parallel and differentiated preheating of multiple hot zones, facilitating automated and precise preheating of multiple hot zones in the mold. This data-driven preheating device reduces manual intervention and operational errors, making the preheating process more efficient and stable. This improves the automation level of mold preheating while ensuring that each hot zone is precisely heated according to the predetermined strategy, enhancing preheating quality and production efficiency.

[0071] In one embodiment, 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 tube methods, both in combination with a second heating power and a second heating speed, to preheat the second hot zone. The preheating strategy for the third hot zone is: using a resistance heating furnace to preheat the third hot zone with a third heating power and a 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.

[0072] Optionally, the ratio of the second heating power to the first heating power is 5, 6, 7, 8, 9, 10, or any value therebetween; 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 therebetween; the ratio of the second heating rate to the first heating rate is 3, 4, 5, 6, 7, 8, 9, 10, or any value therebetween; and the ratio of the third heating rate to the first heating rate is 5, 6, 7, 8, 9, 10, 11, 12, or any value therebetween.

[0073] The first hot zone utilizes infrared heating tubes, known for their fast heating speed and excellent directionality. Combined with a high primary heating power and rate, they enable rapid, targeted heating of highly sensitive areas, compensating for heat loss in these areas. The second hot zone utilizes a combination of electromagnetic induction and infrared heating tubes. Electromagnetic induction achieves uniform overall heating, while the infrared tubes assist with localized fine-tuning. A moderate secondary heating power and rate ensure a uniform temperature rise. The third hot zone utilizes a resistance-heated furnace at a lower third heating power and rate to maintain temperature stability. Specific ratios of heating power and rate in each hot zone ensure that heating intensity and thermal sensitivity are matched across the zone. This combination of heating methods and parameters, optimized for the characteristics of each hot zone, significantly improves preheating effectiveness. Rapid, targeted heating of highly sensitive areas improves temperature uniformity, combined heating of moderately sensitive areas ensures overall temperature consistency, and energy-efficient heating of low-sensitivity areas reduces energy consumption. Overall, this approach improves overall mold thermal efficiency while reducing the likelihood of damage from thermal stress.

[0074] In one embodiment, in the first heating zone, a robot is used to control the infrared heating pipeline to move in a scanning manner along the contour of the first heating zone according to the three-dimensional coordinate data. In the second heating zone, a robot is used to control the infrared heating pipeline to move in a scanning manner along the contour of the second heating zone according to the three-dimensional coordinate data. The resistance heating furnace is provided in correspondence with the third heating zone.

[0075] In the first and second hot zones, the robot controls the infrared heating lines to scan and move along the contours of the hot zones based on the three-dimensional coordinate data, ensuring that the heated areas precisely fit the complex surfaces of the mold and achieving full coverage heating of the hot zones. The resistance heating furnace is set up in correspondence with the third hot zone to uniformly heat the less sensitive areas as a whole, ensuring that the heating method of each hot 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 scanning movement of the infrared heating lines, achieving a heating coverage rate of more than 98% in complex hot zones, avoiding the heating blind spots under traditional fixed heating methods. The stable heating of the less sensitive areas by the resistance heating furnace ensures the balance of the overall temperature of the mold, further improving the quality and consistency of mold preheating.

[0076] Furthermore, there are multiple resistance heating furnaces and they are arranged in a one-to-one correspondence with the third hot zone, which can further improve the heating efficiency and uniformity of the third hot zone.

[0077] In one embodiment, step S40: after preheating the mold according to the preheating strategy, updating the temperature field distribution at each preset interval specifically includes:

[0078] S41: preheating the mold for 30 seconds according to the preheating strategy;

[0079] S42: After preheating, a thermal imaging device is used to perform thermal imaging of the mold surface every 5 to 10 seconds to update the temperature field distribution.

[0080] The mold is first preheated for 30 seconds according to the preheating strategy to allow the mold to initially heat up and reach a certain base temperature. A thermal imaging device then captures the mold surface every 5-10 seconds, collecting real-time surface temperature data. Data processing and analysis update the temperature field distribution, providing real-time and accurate temperature information for subsequent preheating parameter adjustments. Reasonable preheating time and temperature collection intervals ensure the validity and timeliness of temperature field data. The system can quickly capture temperature trends during mold preheating, promptly identifying hot and cold spots, and shortening the response time for preheating parameter adjustments to less than 10 seconds. This effectively avoids thermal stress problems caused by accumulated temperature deviations and improves the dynamic control accuracy and stability of mold preheating.

[0081] Optionally, the thermal imaging device can be Arrow M620 Tianxuan handheld infrared thermal imager, FOTRIC280 series infrared thermal imager, Uni-T UTi640Q high-performance infrared thermal imager, Testo thermal imager series, Gewu Youxin full-frame thermal imager, Gaode Zhigan H series intelligent infrared thermal imager, Marposs TTV panoramic thermal imager or other instruments and equipment that can meet the thermal imaging requirements.

[0082] In one embodiment, step S50: adjusting the mold preheating parameters according to the latest temperature field distribution specifically includes:

[0083] S51: Adjust the heating power of the corresponding hot zone based on the latest temperature field. 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%. 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.

[0084] Based on the updated temperature field distribution, the average temperature of each hot zone is compared. When the average temperature of the first hot zone is lower than that of the second hot zone, the heating power of the first hot zone is increased by 20% to accelerate the heating rate of this area; otherwise, the heating power of the second hot zone is increased. Similarly, after comparing the temperatures of the first and third hot zones, the heating power of the corresponding hot zones is adjusted according to the rules. By continuously adjusting the heating power of each hot zone, the temperature of all hot zones gradually reaches the specified temperature, achieving overall temperature balance in the mold. This dynamic power adjustment mechanism based on the temperature field effectively solves the problem of uneven temperature in the hot zones of the mold. The temperature difference between the hot zones 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 concentration of thermal stress, and reduces the risk of deformation and cracking of the mold due to temperature differences.

[0085] In one embodiment, the designated temperature of the first thermal zone is a first designated temperature T1, the designated temperature of the second thermal zone is a second designated temperature T2, and the designated temperature of the third thermal zone is a third designated temperature T3, and the first designated temperature T1 is greater than the second designated temperature T2 and the third designated temperature T3.

[0086] By setting different preheating temperatures for different hot zones, thermal compensation can be achieved. High-curvature zones (such as the first hot zone) often feature thin walls, narrow slits, and sharp corners within the mold, resulting in a high surface-to-volume ratio. During preheating, heat is easily dissipated through air convection or the mold itself, causing the actual temperature to fall below the target. Setting T1 to a maximum compensates for the thermal shock caused by high-temperature metal slurry temperatures while also dissipating heat, preventing insufficient material fluidity and temperature loss caused by low temperatures. This prevents poor metal filling during die casting and enhances the material's plastic deformation capacity. Tensile stresses generated by shrinkage during molding can be released through high-temperature plastic flow, minimizing stress cracking in thin-walled areas and reducing the filling defect rate. Low-curvature zones (such as the third hot zone) often feature thick-walled, planar structures with high heat capacity (low S / V ratio) and significant heat accumulation. Setting T3 to a minimum prevents mold material softening or grain coarsening caused by overheating, and avoids pearlite spheroidization or carbide precipitation caused by prolonged high-temperature heating. It also reduces ineffective heat input, further lowering production costs.

[0087] Furthermore, the first specified temperature T1, the second specified temperature T2, and the third specified temperature T3 satisfy the following conditions: 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, α is the environmental correction factor and is also a constant. Specifically in this embodiment, n=1 or 2. For example, when n=1, T n is T1, the first specified temperature, T n+1 T2, the second specified temperature, K n K1 is the curvature of the first hot zone, K n+1 K2 is the curvature of the second hot zone, and the first specified temperature and the second specified temperature satisfy: T1 / T2=m(K1 / K2)+C*α.

[0088] It should be noted that the above proportional relationship is also satisfied when the mold surface is divided into more hot zones, such as the fourth hot zone, the fifth hot zone, the sixth hot zone, or a number of other hot zones. That is, n is a positive integer greater than 2.

[0089] The C*α term dynamically adjusts the temperature reference based on actual operating conditions. For example, for mold materials with high thermal conductivity (such as copper alloy molds with large α values), increasing C*α can overall raise the temperature of each hot zone, avoiding insufficient temperature due to rapid heat dissipation from the material. When producing in low-temperature environments, α can also be adjusted to enhance the preheating effect and ensure a stable temperature gradient. By establishing the aforementioned proportional relationship, precise matching of heating parameters can be achieved, and precise setting of hot zone temperatures can be achieved based on the proportional relationship of curvature. This transforms mold preheating from experience-driven to data-driven, further enabling the implementation of corresponding targeted preheating strategies for different molds. Precise heat supply reduces energy consumption, and rapid mold changes improve production efficiency.

[0090] In one embodiment, the preheating strategy switches to the keep warm mode when any thermal zone reaches a designated temperature of the corresponding thermal zone.

[0091] When any hot zone reaches the specified temperature, the preheating strategy automatically switches to hold mode. The heating equipment reduces power or maintains a constant low-power operation to maintain the temperature of the hot zone near the specified temperature, preventing it from overheating or underheating, and ensuring the mold maintains the appropriate temperature during subsequent processing. The timely switch to hold mode effectively avoids mold overheating or rapid temperature drops. Once the mold reaches the target temperature, the temperature fluctuation range can be controlled within ±2°C, ensuring stable mold performance and extending its service life. This reduces product quality fluctuations caused by temperature instability and improves the yield rate of die-cast products.

[0092] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, 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, they should be considered to be within the scope of this specification.

[0093] The above embodiments merely illustrate several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A mold preheating method, characterized in that: The mold preheating method includes the following steps: 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; divide the hot zone sensitivity level according to the scan model, where: 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; Preset mold preheating strategies for hot zones with different levels of thermal sensitivity, including: inputting 3D coordinate data and hot zone sensitivity level data into the preheating device; 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. Among the preheating strategies, the preheating strategy for the first hot zone is: using an infrared heating tube, coordinating 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 coordinating with a second heating power and a second heating speed, to preheat the second hot zone; the preheating strategy for the third hot zone is: using a resistance heating furnace, coordinating with a third heating power and a third heating speed, to preheat the third hot zone; wherein, 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; 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 mold preheating method according to claim 1, 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.

3. The mold preheating method according to claim 1, 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 using a robot control; 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 using a robot control; The resistance heating furnace is arranged corresponding to the third hot zone.

4. The mold preheating method according to claim 1, 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.

5. The mold preheating method according to any one of claims 1 to 4, characterized in that: step: According to the latest temperature field distribution, adjust the mold preheating parameters, including: According to the latest temperature field, the heating power of the corresponding hot zone is adjusted. 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%; 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.

6. The mold preheating method according to claim 5, characterized in that: The designated temperature of the first hot zone is the first designated temperature T1, the designated temperature of the second hot zone is the second designated temperature T2, and the designated temperature of the third hot zone is the third designated temperature T3, and the first designated temperature T1, the second designated temperature T2, and the third designated temperature T3 satisfy the following conditions: 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, α is the environmental correction factor and is also a constant.

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