A decorative strip, injection molding device and injection molding method

Abstract

This invention discloses a decorative strip, an injection molding device, and an injection molding method, relating to the field of hot runner injection molding technology. The device comprises an injection molding machine main unit and a mold system integrated within the main unit. The injection molding machine main unit includes a front mold section, a rear mold section, a hot runner section, and an ejection module. The front mold section, the rear mold section, and the hot runner section all include temperature sensor arrays, pressure sensor arrays, and micro-pressure sensors integrated inside the mold, distributed within the hot runner system and the mold cavity. The ejection module includes a high-speed industrial camera and a laser scanner located at the ejection station. The mold system includes a decision module and a coordination module. The decision module is equipped with a real-time data stream based on a multi-source sensing module and an adaptive cooling control system linked to the ejection module. The multi-source sensing module, the central decision module, and the coordination execution module are interconnected via a data bus to form a closed-loop control circuit, achieving adaptive optimization of parameters throughout the injection molding process.

Description

Technical Field

[0001] This invention relates to the field of hot runner injection molding technology, and in particular to a decorative strip, injection molding device and injection molding method. Background Technology

[0002] In the field of automotive exterior and sealing, injection molding of decorative strips is an important process for achieving complex shapes and multi-functional integration. This process usually involves injecting molten plastic into a mold cavity, which is then cooled and shaped to produce a part that combines decoration and functionality. However, while pursuing high surface quality such as high gloss, flawless, and complex structures such as three-color integration and double-sided adhesive, the injection molding process still faces significant technical challenges in terms of multi-material bonding reliability, precise temperature control, anti-warping of large and slender parts, and production efficiency.

[0003] Chinese Patent Application No. 202311457204.3 discloses an injection molding mold for a side panel trim strip on a car body. The mold includes a moving mold insert, a protective shell on the moving mold insert, a hot runner system on the protective shell, a fixed mold insert on the protective shell, a mounting box fixedly connected to the moving mold insert, a mounting block fixedly connected to the mounting box, the mounting block contacting the moving mold insert, a limit mechanism on the mounting block, a connecting block slidably connected inside the mounting box, the connecting block contacting the moving mold insert, a guide block fixedly connected to the connecting block, a threaded rod connected to the mounting box via a bearing, a rotating shaft rotatably connected inside the mounting box, and a knob fixedly connected to the rotating shaft. This invention features high precision in the fit between the mold and the trim strip, and reduces production costs.

[0004] Similar to the existing technologies described above, during the injection molding process, due to the shear heating effect, the actual temperature of the melt will be significantly higher than the set value. Traditional static temperature control cannot effectively compensate for this, which leads to problems such as uneven filling and surface defects. Furthermore, the problem of product warping and deformation is particularly prominent in subsequent processes such as holding pressure and shrinkage compensation, cooling and shaping, and mold opening and ejection. Improper setting of holding pressure and time can cause shrinkage cavities or shrinkage marks inside the product, while uneven cooling will directly cause product warping and deformation. During the mold opening and ejection process, if the product is not cooled sufficiently or the ejection system is not designed properly, the deformation will be aggravated due to uneven release of internal stress.

[0005] In hot runner injection molding, the melt filling stage, as the initial stage of the entire molding process, is a fundamental and decisive factor affecting product quality. However, traditional injection molding processes have significant shortcomings in the coordinated control of multiple gates. When the injection parameters between gates fail to coordinate effectively, the system lacks a real-time feedback adjustment mechanism. For example, if the melt viscosity changes due to shear heat during injection, traditional open-loop control cannot achieve real-time compensation, resulting in uneven melt front temperature and disruption of flow balance. This not only forms obvious weld lines but also causes uneven orientation distribution at the molecular chain level. Such internal stress unevenness will be further amplified in the subsequent holding and cooling stages, leading to warping deformation that is difficult to remedy through parameter adjustments.

[0006] Given the aforementioned challenges, achieving real-time and precise control of melt flow during multi-gate injection molding, and effectively addressing issues such as uneven molecular orientation and internal stress concentration caused by temperature fluctuations and timing deviations, has become a core technological bottleneck in constructing a high-precision injection molding system.

[0007] Therefore, it is necessary to invent a corresponding injection molding device and injection molding method to solve the above problems. Summary of the Invention

[0008] To achieve the above objectives, the present invention provides the following technical solution: a decorative strip injection molding device, the device comprising an injection molding machine main unit and a mold system integrated within the main unit, the injection molding machine main unit including a front mold section, a rear mold section, a hot runner section and an ejection module;

[0009] The front mold section, the rear mold section, and the hot runner section all include temperature sensor arrays, pressure sensor arrays, and micro pressure sensors integrated inside the mold, distributed in the hot runner system and the mold cavity.

[0010] The ejection module includes a high-speed industrial camera and a laser scanner located at the ejection station.

[0011] The mold system includes a decision module and a coordination module. The decision module is configured to receive real-time data streams from multi-source sensing modules and perform conditional judgments based on a built-in expert rule base to generate process parameter adjustment instructions. The expert rule base encapsulates domain knowledge of thermo-fluid-force coupling and contains multiple judgment rules for detection conditions and execution actions. Meanwhile, precise and stable control of continuous quantities such as temperature and pressure is achieved by an independent control loop based on the PID control principle. The coordination module includes a zoned independent temperature-controlled hot runner system, a sequential valve control system with dual feedback of position and pressure, and an adaptive cooling control system linked with the ejector module.

[0012] The multi-source sensing module, central decision-making module, and collaborative execution module are interconnected through a data bus to form a closed-loop control circuit, enabling adaptive optimization of parameters throughout the injection molding process.

[0013] Preferably, the mold system further includes a multi-source sensing module and a central processing module. The data acquired by the multi-source sensing module includes temperature sensor array data and pressure sensor array data distributed in the hot runner system and mold cavity, micro pressure sensor data integrated inside the mold, and data detected by a high-speed industrial camera and laser scanner set at the ejection station.

[0014] Preferably, the front mold includes an upper mold, the upper mold is provided with an injection port communicating with the hot flow section, the upper mold is also provided with a first cavity adapted to the injection molded part, and the first cavity is provided with a pressure detection unit, which captures pressure change data at a millisecond frequency through a nanoscale piezoelectric sensor installed at a key position in the first cavity;

[0015] The rear mold includes a lower mold, and the lower mold is provided with a second cavity corresponding to the first cavity. The second cavity is provided with a pressure detection unit, which captures pressure change data at a millisecond frequency through a nanoscale piezoelectric sensor at a key position in the second cavity.

[0016] The pressure detection unit installed in the first cavity and the second cavity can capture the pressure change data in the cavity and transmit the data to the decision module. The decision module can compare and analyze the real-time pressure data with the preset pressure curve to determine whether the filling process is balanced, and dynamically adjust the injection parameters of the hot flow section according to the pressure fluctuation amplitude.

[0017] Preferably, the hot runner includes a feed inlet connected to the injection port, and the hot runner also includes a heating chamber, which is equipped with a temperature monitoring unit that collects melt temperature data in real time through multiple high-precision sensors distributed in the hot runner and mold cavity.

[0018] The temperature detection unit, through a distributed thermocouple array arranged in an equilateral triangle in the hot runner system, can collect melt temperature data in real time at a preset sampling frequency. The decision module can compare the temperature data with a preset temperature threshold and combine it with the pressure value detected by the cavity pressure detection unit. When the temperature deviation is detected to exceed the allowable range, the heating power output is automatically adjusted to maintain the melt temperature stability.

[0019] Preferably, the high-speed industrial camera can capture real-time images of the injection molded part surface using a multispectral light source to identify defects; the laser scanner can perform a full-range three-dimensional scan of the ejected injection molded part to obtain warpage deformation data; the decision module can comprehensively evaluate the quality of the injection molded part based on the images and scan data, and generate adjustment instructions to be fed back to the collaboration module.

[0020] Preferably, the collaborative module includes a zoned independent temperature-controlled hot runner system, which can implement differentiated temperature control for different areas of the mold according to the instructions of the decision module; the sequential valve needle control system can accurately adjust the valve needle opening sequence and speed based on position and pressure dual feedback signals to ensure balanced filling of multiple gates;

[0021] The decision-making module is also equipped with a feedback unit, which can adjust other modules based on the data obtained from the decision-making module.

[0022] The ejection module also includes an adaptive cooling control system, which can dynamically adjust the cooling water flow rate and duration based on real-time temperature distribution data of the injection molded part; the decision module can predict the cooling effect through thermo-fluid-force coupling simulation and optimize cooling parameters to reduce deformation caused by internal stress.

[0023] The present invention also provides a method for injection molding decorative strips, the method utilizing the aforementioned decorative strip injection molding apparatus to perform injection molding operations, comprising the following steps:

[0024] S100, Parameter Initialization Stage: The historical best process parameters are loaded through the central processing module, and the injection parameters are adaptively corrected based on the characteristics of the current material batch.

[0025] S200, Multi-gate Co-injection Stage: The melt state is monitored in real time by the temperature detection unit and pressure detection unit, and the multi-gate balanced filling is achieved by combining the sequence valve co-control module;

[0026] S300, Pressure Holding and Cooling Optimization Stage: Obtain injection molded part morphology data through the laser scanner, and optimize pressure holding and cooling parameters based on the warpage prediction model output results;

[0027] S400, Ejection and Verification Stage: Quality assessment is performed through the feedback unit, and when a defect is detected, process parameters are traced and the prediction model is updated.

[0028] Preferably, S200 includes:

[0029] S210. Initial filling is performed through an open gate in the middle, and the injection pressure curve is dynamically adjusted based on real-time viscosity monitoring values.

[0030] S220. When the pressure value detected by the cavity pressure sensor reaches the preset trigger threshold, the sequential valve gates on both sides are opened according to the preset timing command. The valve needle opening is controlled by the fixed flow ratio parameter preset for each gate, thereby replacing complex dynamic calculations and maintaining melt flow balance in a stable and reliable manner.

[0031] S230 calculates the temperature rise increment caused by shear heat generation in real time and adjusts the heating power output in advance through feedforward control.

[0032] Preferably, S300 includes:

[0033] S310, Inversion of shrinkage stress distribution based on in-mold stress sensor data;

[0034] S320: Automatically generates customized pressure holding curves based on stress distribution gradients to achieve differentiated pressure holding in different zones;

[0035] S330 uses temperature field equalization technology to control the temperature gradient on the cavity surface, ensuring uniform cooling.

[0036] The present invention also provides a decorative strip, which is injection molded using the above-described decorative strip injection molding device.

[0037] The technical effects and advantages of this invention are as follows:

[0038] This invention employs a specific injection molding front mold, upper mold, rear mold, and lower mold structure. Based on temperature, pressure, and deformation data streams collected by a multi-source sensing module, a decision module performs real-time simulation analysis of the coupled thermal, fluid, and force fields. A distributed thermocouple array tracks melt temperature changes in real time, controlling actual melt temperature fluctuations within a preset range. This suppresses molecular chain orientation anomalies caused by temperature unevenness at the source. Simultaneously, based on the product's three-dimensional morphology data obtained by a laser scanner, a warpage prediction model is constructed. This forms a data-driven, predictive control-based intelligent production system. It not only achieves collaborative optimization of the entire injection molding process but also enables the system to adapt to material fluctuations and environmental changes. Ultimately, it represents a technological leap in quality control from post-treatment remediation to pre-treatment prevention in the field of decorative strip injection molding, effectively solving the problems of uneven molecular orientation and internal stress concentration caused by temperature fluctuations and timing deviations in multi-gate injection molding. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0040] Figure 2 This is a schematic diagram of the overall structure of the front mold part of the present invention.

[0041] Figure 3 This is a schematic diagram of the upper mold structure of the present invention.

[0042] Figure 4 This is a schematic diagram of the overall structure of the rear mold part of the present invention.

[0043] Figure 5 This is a schematic diagram of the lower mold structure of the present invention.

[0044] Figure 6 This is a schematic diagram of the split structure of the heat flow section of the present invention.

[0045] Figure 7 This is a schematic diagram of the method flow of the present invention.

[0046] Figure 8 This is a schematic diagram of the overall logic of the present invention.

[0047] Figure 9 This is a schematic diagram of the injection molding process logic of the present invention.

[0048] Figure 10 This is a schematic diagram of the pressure holding, cooling, and defect detection process of the present invention.

[0049] Figure 11 This is a schematic diagram of the decorative strip of the present invention.

[0050] Figure 12 This is a microscopic comparison image of weld line defects on the surface of the injection molded part of the present invention.

[0051] In the diagram: 1. Front mold section; 11. Upper mold; 12. Injection port; 13. First cavity; 2. Rear mold section; 21. Lower mold; 22. Second cavity; 3. Hot runner section; 31. Feed port; 32. Heating cavity; 4. Ejection module. Detailed Implementation

[0052] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] To address the issues of low automation levels in existing decorative strip injection molding equipment, problems such as unreliable multi-material bonding, precise temperature control, anti-warping of large and slender parts, and low production efficiency during the injection molding process.

[0054] like Figures 1 to 12 As shown, in the first embodiment of the present invention, a decorative strip injection molding device is proposed. The device includes an injection molding machine main unit, which includes a front mold part 1, a rear mold part 2, a hot runner part 3, and an ejection module 4.

[0055] In this embodiment, the front mold part 1 includes an upper mold 11, which is provided with an injection port 12 communicating with the hot flow part 3. The upper mold 11 is also provided with a first cavity 13 adapted to the injection molded part. The rear mold part 2 includes a lower mold 21, which is provided with a second cavity 22 corresponding to the first cavity 13. The first cavity 13 and the second cavity 22 together constitute the injection molded cavity.

[0056] It should be noted that the front mold part 1 also includes a housing that supports the upper mold 11, and the rear mold part 2 also includes a housing that supports the lower mold 21. The main body of the injection molding machine also includes a drive mechanism, which can be composed of hydraulic or electric servo mechanisms. Its main function is to realize the opening and closing of the upper mold 11 and the lower mold 21, and the ejection of the injection molded part 5. The main body of the injection molding machine also includes a mold locking mechanism, which can apply a locking force to the front mold part 1 and the rear mold part 2 to ensure that the mold is stable and sealed during the injection process.

[0057] In this embodiment, the heat flow section 3 includes a feed inlet 31, which is connected to the injection port 12, and the heat flow section 3 also includes a heating chamber 32.

[0058] It should be noted that the heat flow section 3 also includes an insulation shell, the heating chamber 32 is opened inside the insulation shell, and the insulation shell is provided with a guide cavity adapted to the feed port 31. The guide cavity and the heating chamber 32 are not connected to each other. The heating chamber 32 is also provided with a heating component, which can raise the temperature in the flow channel of the heating chamber 32 by electric heating, thereby heating the injection plastic in the guide cavity.

[0059] In this embodiment, the hot flow section 3 also includes an injection molding assembly, which is capable of moving the molten material within the hot flow section 3.

[0060] In this embodiment, the ejection module 4 includes a high-speed industrial camera and a laser scanner located at the ejection station, which can scan the dimensions of the injection molded part after injection molding.

[0061] It should be noted that the ejector module 4 also includes multiple ejector pins adapted to the lower mold 21. These pins are controlled by a drive mechanism to separate the injection molded part from the lower mold 21. Furthermore, the housing in the rear mold section 2 that carries the lower mold 21 is equipped with a circulating cooling assembly, which can cool and maintain the pressure of the injection molded part after injection molding.

[0062] In this embodiment, the device also includes a mold system integrated into the injection molding machine host. The mold system includes a decision module and a coordination module, which can control the various components in the injection molding machine host to work according to the predetermined stroke to achieve automated injection molding operation.

[0063] It should be noted that, as Figure 3As shown, the injection molding machine host adopts three-point hot runner injection molding. Its injection port 12 is set to three, of which the middle injection port 12 is an open injection port, and the injection ports 12 on both sides are equipped with sequence valves. The injection cavity composed of the upper mold 11 and the lower mold 21 is also equipped with an exhaust component, which can exhaust the excess gas in the injection cavity to the outside.

[0064] When in use, the decision module first calls the pre-stored optimal process parameter package, and the coordination module then starts the mold closing program. The drive mechanism pushes the front mold part 1 and the rear mold part 2 to close precisely. The first cavity 13 of the upper mold 11 and the second cavity 22 of the lower mold 21 together form a complete injection cavity. The mold clamping mechanism then applies the set clamping force to ensure that the mold remains stable and sealed during high-pressure injection.

[0065] After the mold is closed, the hot runner 3 begins to operate. The electric heating component in the heating chamber 32 heats the plastic raw material to the preset melting temperature. The decision module dynamically adjusts the heating power according to the material characteristics. Driven by the injection system, the molten plastic is injected into the cavity through the feed port 31 and the injection port 12. During this process, the device adopts a three-point hot runner injection molding technology. The central open injection port 12 opens first for initial filling, while the injection ports 12 with sequential valves on both sides are controlled by the decision module according to the feedback from the pressure sensor in the cavity. This ensures that the melt front advances evenly, reduces flow imbalance and weld lines. The gas in the cavity is discharged through a specially designed venting component to avoid product defects caused by trapped gas.

[0066] After the filling stage, the system immediately enters the holding pressure stage. The collaborative module applies multi-level holding pressure according to the decision instructions to compensate for melt cooling and shrinkage, reducing shrinkage marks and voids inside the product. At the same time, the circulating cooling component in the rear mold section 2 housing is activated, which uniformly and efficiently cools the mold by regulating the flow and temperature of the coolant, promoting the solidification and shaping of the injection molded part in the cavity. During this process, the temperature sensor continuously monitors the mold temperature changes and feeds the data back to the decision module in real time, thereby dynamically optimizing the cooling time and ensuring the dimensional stability of the product.

[0067] After the pressure holding and cooling process is completed, the drive mechanism performs the mold opening action. The front mold part 1 and the rear mold part 2 separate, and multiple ejector pins of the ejector module 4 are ejected upward under the control of the drive mechanism, so that the molded injection part can be smoothly demolded from the lower mold 21. After demolding, the high-speed industrial camera and laser scanner at the ejection station immediately perform three-dimensional scanning and visual inspection on the injection part, accurately collecting key quality data such as surface defect characteristics and warpage deformation. These data are transmitted to the decision module in real time and compared with the preset quality indicators. If dimensional deviations or surface defects such as weld lines are detected, the decision module will automatically trace all process parameter records of the production cycle, intelligently generate optimization instructions and feed them back to the collaboration module, thereby adjusting the injection speed, pressure holding curve or cooling parameters of the next production cycle.

[0068] However, in actual use, operators have found that during the injection molding process, the actual temperature of the melt is often too high due to shear heat, exceeding the set value. Traditional static temperature control methods are difficult to effectively compensate for this dynamic fluctuation, which easily leads to uneven filling and surface defects. In the subsequent holding pressure, cooling and shaping, and mold opening and ejection stages, the product warping and deformation problems are significant. Inappropriate holding pressure and time can lead to internal shrinkage cavities or shrinkage marks, while uneven cooling directly causes warping. If the product is not cooled sufficiently during ejection or the ejection system is poorly designed, the deformation will be aggravated by uneven release of internal stress. In hot runner injection molding, the melt filling stage is crucial, but traditional processes have obvious shortcomings in the coordinated control of multiple gates. When the injection parameters of each gate are not synchronized and there is a lack of real-time feedback adjustment, the changes in melt viscosity caused by shear heat cannot be compensated, resulting in uneven melt front temperature and disruption of flow balance. This not only produces obvious weld lines but also causes uneven molecular chain orientation. This uneven internal stress is amplified in subsequent processes, ultimately causing warping that is difficult to correct.

[0069] Therefore, in order to solve the above-mentioned technical problems, in another embodiment of the present invention, the device further includes: the front mold part 1, the rear mold part 2 and the hot runner part 3 each include a temperature sensor array, a pressure sensor array and a micro pressure sensor integrated inside the mold, which are distributed in the hot runner system and the mold cavity.

[0070] In this embodiment, a pressure detection unit is provided in the first cavity 13, which captures pressure change data at a millisecond frequency through a nanoscale piezoelectric sensor installed at a key position in the first cavity 13. A pressure detection unit is provided in the second cavity 22, which captures pressure change data at a millisecond frequency through a nanoscale piezoelectric sensor installed at a key position in the second cavity 22.

[0071] In this example, the pressure detection unit located in the first cavity 13 and the second cavity 22 can capture the pressure change data in the cavity and transmit the data to the decision module. The decision module can compare and analyze the real-time pressure data with the preset pressure curve to determine whether the filling process is balanced, and dynamically adjust the injection parameters of the heat flow section 3 according to the pressure fluctuation amplitude.

[0072] In this embodiment, a temperature monitoring unit is provided in the heating chamber 32. It collects melt temperature data in real time through multiple high-precision sensors distributed in the hot runner and mold cavity. The temperature detection unit is arranged in the hot runner system in an equilateral triangle according to a distributed thermocouple array. It can collect melt temperature data in real time according to a preset sampling frequency. The decision module can compare the temperature data with the preset temperature threshold and combine it with the pressure value detected by the cavity pressure detection unit. When the temperature deviation is detected to exceed the allowable range, the heating power output is automatically adjusted to maintain the melt temperature stability.

[0073] In this embodiment, a high-speed industrial camera can capture real-time images of the injection molded part surface using a multispectral light source to identify defects, and a laser scanner can perform a full-range three-dimensional scan of the ejected injection molded part to obtain warpage deformation data. The decision module can comprehensively evaluate the quality of the injection molded part based on the images and scan data, and generate adjustment instructions to be fed back to the collaboration module.

[0074] In this embodiment, the collaborative module includes a zoned independent temperature-controlled hot runner system, which can implement differentiated temperature control for different areas of the mold according to the instructions of the decision module. The sequential valve needle control system can accurately adjust the valve needle opening timing and speed based on position and pressure dual feedback signals to ensure balanced filling of multiple gates. The decision module also has a feedback unit, which can combine the data obtained by the decision module to provide feedback adjustment to other modules.

[0075] In this embodiment, the ejection module 4 also includes an adaptive cooling control system, which can dynamically adjust the cooling water flow rate and duration according to the real-time temperature distribution data of the injection molded part. The decision module can predict the cooling effect through thermal-fluid-force coupling simulation and optimize the cooling parameters to reduce deformation caused by internal stress.

[0076] In this embodiment, the mold system includes a decision-making module and a coordination module. The mold system also includes a multi-source sensing module, which acquires data from temperature sensor arrays and pressure sensor arrays distributed in the hot runner system and mold cavity, micro-pressure sensors integrated inside the mold, and data detected by a high-speed industrial camera and laser scanner set at the ejection station.

[0077] In this embodiment, the decision module is configured with a real-time data stream based on the multi-source sensing module, and compares the data with preset process parameter thresholds and an expert rule base to generate specific process parameter adjustment instructions. The expert rule base contains multiple condition judgment rules based on the thermal-fluid-force coupling relationship, which are used to realize the adaptive optimization of the device.

[0078] It should be noted that the adaptive optimization function in the decision-making module can be implemented by building an expert rule base. The construction of the expert rule base is based on a large number of process experiments and expert experience, which concretizes the thermal-fluid-mechanical coupling relationship into executable conditional rules.

[0079] It should be noted that the expert rule base is constructed using a modular design, organizing rule logic in the form of a decision tree. Each rule contains clearly defined triggering conditions, data thresholds, and execution actions, forming an executable "condition-action" paradigm. For example, the basic rule framework is set as follows: when the temperature deviation ΔT in a region exceeds 5°C and the pressure fluctuation ΔP is greater than 0.5MPa, the system automatically executes adjustments to reduce the heating power in that region by 10% and decrease the injection speed by 5%. This rule is triggered by real-time data streams, such as millisecond-level sampling from thermocouple arrays and pressure sensors, ensuring a rapid response in the injection molding process.

[0080] To address material differences, the rule base dynamically adjusts thresholds and actions based on the thermal properties of common decorative strip materials: for ABS materials, due to their high melt temperature sensitivity, the rules set a stricter ΔT threshold, such as 3°C, and the actions focus on fine-tuning the heating power to prevent thermal degradation; while for PC materials, given that their viscosity changes significantly with shear, the rules add viscosity monitoring conditions, such as dynamically adjusting the opening of the sequence valve when the melt viscosity change rate exceeds 10% to balance the flow front and avoid uneven filling caused by viscosity fluctuations.

[0081] In terms of structural adaptability, the rule base optimizes the anti-warping strategy based on the geometric features of the decorative strip: for thin-walled structures, such as those with a wall thickness of less than 2mm, the rule focuses on controlling the cooling uniformity. For example, when the laser scanner detects a warping amount exceeding 0.1mm, the cooling water flow rate in the warped area is automatically increased by 20%.

[0082] For complex structures such as multi-curved surfaces, three-dimensional temperature field simulation is combined with the introduction of regional weighting factors to achieve zonal optimization. For example, the holding pressure of different regions is allocated through a thermo-fluid-mechanical coupling model.

[0083] The rule optimization method is based on orthogonal experiments and expert experience iterative generation. For example, for ABS material decorative strips, 100 sets of experiments are conducted by changing parameters such as injection speed and holding pressure. Temperature, pressure and deformation data are collected, and the optimal rule threshold is fitted. The parameter threshold is adjusted through a limited number of experiments. The rule library can be reproduced without excessive experiments. In addition, the threshold is also iteratively optimized through thermo-fluid-mechanical coupling simulation: when the simulation shows that ΔT>5°C will cause the weld line visibility to exceed the standard, this value is set as the threshold to trigger adjustment.

[0084] If the actual melt temperature detected by the thermocouple in a certain area of ​​the hot runner is higher than the set value and the cavity pressure sensor shows increased pressure fluctuation, it is determined that the shear heat generation is too high, and the heating power and injection speed in that area are automatically reduced by a preset step size.

[0085] If the laser scanner detects that the warpage of a specific area of ​​the product exceeds the standard value after ejection, the flow rate of the corresponding cooling water circuit in that area will be automatically increased and the pressure holding time of that area will be extended in the next cycle.

[0086] In this embodiment, the collaborative module includes a zoned independent temperature-controlled hot runner system, a sequential valve control system with dual feedback of position and pressure, and an adaptive cooling control system linked with the ejector module 4. The multi-source sensing module, the central decision-making module, and the collaborative execution module are interconnected through a data bus to form a closed-loop control loop, thereby achieving adaptive optimization of parameters throughout the injection molding process.

[0087] It should be noted that the quantification of the thermo-fluid-force coupling relationship is achieved by the decision module taking the raw data collected by distributed sensors, such as temperature data from thermocouple arrays, pressure data from nanoscale piezoelectric sensors, and stress data from micro-pressure sensors, and inputting them into the coupling equation for millisecond-level calculation.

[0088] Among them, thermal field quantization is based on Fourier's heat transfer law. It uses an equilateral triangular array of thermocouples to monitor the three-dimensional temperature field distribution and calculate the temperature gradient of the melt in the flow channel and cavity.

[0089] Among them, the flow field quantification is based on the viscosity variation with shear rate captured by non-Newtonian fluid dynamics combined with pressure sensor array.

[0090] Among them, force field quantization analyzes the internal stress sensor data through Hooke's law to invert the distribution of internal stress generated by cooling contraction. The specific embodiment of the coupling relationship is a dynamic mapping mechanism: when a temperature deviation ΔT in a certain region is detected, the system automatically correlates the viscosity decrease rate with the increase in contraction stress in that region, forming a quantitative relationship of "temperature-viscosity-stress".

[0091] It should be noted that the generation of adjustment instructions is based on the collaborative work of the rule engine and the control algorithm. The rule engine uses the Rete algorithm for multi-condition matching: when multi-source data meets preset conditions such as ΔT>5°C and ΔP>0.5MPa, the corresponding action in the expert rule base is triggered. For example, the adjustment instruction with a preset step size is actually implemented through the PID control principle, and its step size calculation formula is:

[0092] ΔP = Kp × e(t) + Ki × ∫e(t) dt

[0093] Wherein, ΔP: represents the output change of the adjustment command, i.e., the adjustment step size of the actuator, such as a heater or injection system. The positive or negative sign indicates an increase or decrease operation. For example, when ΔP is negative, the system reduces power by a preset step size to compensate for overheating; Kp is the proportional gain coefficient. The larger the Kp value, the more sensitive the adjustment; e(t) is the real-time error signal, representing the deviation between the actual value monitored by the sensor, such as melt temperature or pressure, and the preset target value at time t; Ki is the integral gain coefficient, used to eliminate steady-state error, i.e., long-term deviation, by compensating for the accumulated error value; ∫e(t)dt: represents the integral of the error e(t) over time, i.e., the accumulated error from the start of the process to the current time, ensuring that the adjustment command can correct persistent deviations.

[0094] It should be noted that the decision-making module adopts a spatiotemporal alignment and weighted fusion strategy. First, it interpolates and synchronizes millisecond-level sensor data, such as temperature or pressure, with visual data, such as laser scanner point clouds, using a unified timestamp, and maps the data to a three-dimensional mesh based on the mold coordinate system. Then, it performs Z-score standardization on continuous variables such as temperature and pressure, normalizes visual defect features such as weld line length, calculates the weights of each data source using the entropy weight method, and finally inputs the weighted data into the expert rule base and PID control loop for parallel processing.

[0095] The system addresses this through priority grading and confidence assessment. Safety rules, such as overheat prevention, have the highest priority; quality rules, such as warpage prevention, have the second highest priority; and efficiency rules, such as cycle time optimization, have the lowest priority. Furthermore, the system dynamically adjusts rule weights based on sensor data reliability; for example, the confidence level of data from nanoscale piezoelectric sensors is higher than that of thermocouples. Specifically, when a conflict arises between exceeding temperature limits (requiring cooling) and insufficient pressure (requiring acceleration), the system prioritizes the higher-priority cooling action and limits the acceleration action (requiring acceleration due to insufficient pressure), such as limiting the injection speed increase to no more than 5%.

[0096] The adaptive optimization uses incremental PID parameter self-tuning and historical data feedback to achieve iteration. After each production cycle, the quality assessment results, such as warpage, are associated with process parameters, and the threshold of the expert rule base is updated. For example, if the warpage continues to decrease, the allowable temperature range of ±1°C is relaxed. Finally, through the rolling optimization mechanism, the quality data is fed back to the parameter initialization stage during the ejection and verification stages, forming a closed-loop iteration.

[0097] When the decorative strip injection molding device starts operating, the decision module first calls the optimal parameter package that matches the current material batch from the pre-stored process library. The coordination module then starts the mold closing program, the drive mechanism pushes the front mold part 1 and the rear mold part 2 to close precisely, and the mold locking mechanism applies a preset locking force simultaneously to ensure that the mold remains stable and sealed during high-pressure injection.

[0098] After mold closing, the hot runner section 3 begins operation. The electric heating components within the heating chamber 32 heat the plastic raw material to the set melting temperature. A distributed thermocouple array, arranged in an equilateral triangle, collects temperature data from the flow channel in real time. Based on temperature sensor feedback, the decision module dynamically adjusts the heating power to maintain the melt temperature within the hot runner section 3 consistently within the preset range.

[0099] During the injection molding process, the multi-source sensing module synchronously collects the following key data: a nanoscale piezoelectric sensor monitors cavity pressure fluctuations at millisecond frequencies, a micro-pressure sensor detects stress changes inside the mold, and a thermocouple array continuously tracks the melt temperature distribution. When the melt temperature is detected to be lower than the set value (i.e., due to heat loss), the heating power is automatically increased; when the temperature is higher than the set value (i.e., due to shear heat), the power output is reduced to stabilize the melt temperature within the preset range. When the decision module analyzes the melt viscosity change caused by shear heat through the thermo-fluid-mechanical coupling model (e.g., a sudden increase in viscosity), a dynamic compensation mechanism is immediately activated: first, the injection speed is reduced to decrease shear heat generation, and the power of the corresponding area of ​​the heating chamber 32 is finely adjusted. When local temperature unevenness is detected, the melt flow path is changed by adjusting the opening sequence of the sequence valve, and temperature equalization is achieved by utilizing the melt's own shear heat.

[0100] After injection molding is completed, the system takes the control parameters, such as the actual injection curve, temperature compensation value, and valve timing, as input and performs an online simulation of the coupling of the thermal, fluid, and force fields to predict the optimal parameters for subsequent processes: For the holding pressure stage, a differentiated holding pressure curve is generated based on the simulated shrinkage stress distribution; for cooling and shaping, the opening of each cooling channel valve is dynamically adjusted based on the temperature field simulation results to keep the mold temperature gradient within the preset range; in the mold opening and ejection stage, the ejection speed curve is optimized based on stress simulation data, and a slow-fast-slow three-stage ejection is adopted to release internal stress.

[0101] After the pressure holding and cooling process is completed, the high-speed industrial camera and laser scanner of the ejection module 4 immediately start detection: the camera identifies surface weld lines through multispectral imaging, and the scanner measures the warpage deformation with an accuracy of ±0.001mm. These data are transmitted to the decision module in real time for comparison and analysis. If local weld lines are found to exceed the standard, the decision module traces the temperature fluctuation record of the area during the injection stage and determines that the improper opening sequence of the sequence valve has caused flow imbalance. Then, an optimization instruction is generated: in the next cycle, the opening time of the sequence valve in the area is advanced or delayed, and the corresponding injection speed is increased or decreased.

[0102] If the scan shows that the warpage exceeds the preset value, the system automatically correlates with the pressure holding and cooling data, finds that the stress concentration is caused by uneven cooling, and immediately adjusts the cooling parameters for the next cycle, increases the cooling water flow rate in the warpage area, and adds additional compensation pressure to the area during the pressure holding stage.

[0103] Through the closed-loop mechanism of injection molding process control – rule determination – quality verification, this device achieves cross-process collaborative optimization. All adjustment parameters are stored in the process database. The system continuously optimizes the control strategy by iteratively updating the thresholds and action parameters in the expert rule base based on data, ultimately forming a global production closed loop of "real-time monitoring – rule determination and PID control – parameter optimization – effect verification." This effectively solves the problem that the melt viscosity change caused by shear heat cannot be compensated in real time, leading to uneven melt front temperature, disruption of flow balance, and consequently, obvious weld lines and uneven molecular chain orientation. By using feedforward and feedback control based on preset rules, the system suppresses this internal stress unevenness at its source, preventing it from being amplified in subsequent processes, and ultimately effectively avoiding the difficult-to-correct warpage problem.

[0104] In another embodiment of the present invention, based on the above-described decorative strip injection molding apparatus, the present invention further includes a decorative strip injection molding method, comprising the following steps:

[0105] S100, Parameter Initialization Stage: The central processing module loads the historical best process parameters and adaptively corrects the injection parameters based on the characteristics of the current material batch.

[0106] S200, Multi-gate Co-injection Stage: The melt state is monitored in real time by the temperature detection unit and pressure detection unit, and the multi-gate balanced filling is achieved by combining the sequence valve co-control module.

[0107] S300, Pressure Holding and Cooling Optimization Stage: The laser scanner is used to acquire the morphology data of the injection molded part, and the pressure holding and cooling parameters are optimized based on the output results of the warpage prediction model.

[0108] S400, Ejection and Verification Stage: Quality assessment is performed through the feedback unit, and when a defect is detected, process parameters are traced and the prediction model is updated.

[0109] In this embodiment, S200 includes:

[0110] S210. Initial filling is performed through an open gate in the middle, and the injection pressure curve is dynamically adjusted based on real-time viscosity monitoring values.

[0111] S220. When the pressure value detected by the cavity pressure sensor reaches the preset trigger threshold, the sequential valve gates on both sides are opened according to the preset timing command. The valve needle opening is controlled by the preset fixed flow ratio parameter for each gate, thereby replacing complex dynamic calculations and maintaining melt flow balance in a stable and reliable manner.

[0112] It should be noted that the control logic of the sequence valves preferably adopts a multi-cascade control method based on threshold triggering. That is, during the system debugging phase, the opening sequence of each sequence valve and the optimal opening ratio of each valve needle are preset according to the flow channel geometry and material properties. During the production process, when the cavity pressure sensor reaches the threshold, the system does not perform complex real-time pressure equalization calculations, but directly executes the preset timing and ratio commands. This control method based on preset rules reduces system complexity and dependence on computing resources, and improves the system's response speed and control stability, making it particularly suitable for long-term stable operation in industrial settings.

[0113] S230 calculates the temperature rise increment caused by shear heat generation in real time and adjusts the heating power output in advance through feedforward control.

[0114] The S300 includes:

[0115] S310, Shrinkage stress distribution inverted based on in-mold stress sensor data.

[0116] S320: Automatically generates customized pressure holding curves based on stress distribution gradients to achieve differentiated pressure holding in different zones.

[0117] S330 uses temperature field equalization technology to control the temperature gradient on the cavity surface, ensuring uniform cooling.

[0118] In another embodiment of the invention, such as Figure 11 As shown, the present invention also provides a decorative strip generated using the above-described decorative strip injection device and decorative strip injection method.

[0119] In another embodiment of the present invention, in order to verify the effectiveness of the decorative strip injection molding system based on multi-source perception and expert rule base proposed in the present invention, especially its technical advantages in solving the flow imbalance and long-term warping deformation caused by shear heat generation, the applicant conducted a comparative experiment.

[0120] Experimental subject: A high-gloss ABS decorative strip for a car dashboard, 850mm long and 2.5mm thick, exhibiting typical characteristics of large length-to-diameter ratio and easy deformation.

[0121] Experimental material: ABS resin.

[0122] Injection molding equipment:

[0123] Example group: An injection molding device equipped with the decision module, collaboration module, micro pressure sensor, temperature sensor array and laser scanner of the present invention, and using an expert rule base for adaptive control.

[0124] Comparative group: Using standard injection molding machines of the same tonnage, equipped with a traditional PID temperature control three-point hot runner system, without cavity pressure feedback, without visual closed-loop adjustment, and produced according to fixed process parameters.

[0125] Testing cycle: Each of the two groups will produce 500 molds continuously, and samples will be taken for testing.

[0126] Comparison of experimental data:

[0127] Comparison of injection molding process stability and product quality data:

[0128]

[0129] like Figure 12 As shown in the figure, this is a close-up microscopic view of the highlight area on the surface of the injection molded part, showing the quality difference at the melt confluence.

[0130] The left side shows the control group without adaptive control: corresponding to the comparative group in the experimental data. Due to uneven flow front temperature and unstable pressure, the melt merged poorly, leaving clearly visible weld lines on the surface, accompanied by flow marks, which seriously affected the appearance quality.

[0131] The right side shows the example group with adaptive control, corresponding to the experimental data. This invention ensures a balance of melt temperature and flow rate in each channel through real-time monitoring and adjustment, resulting in thorough fusion at the melt junction. Weld lines are virtually invisible, and the surface exhibits a uniform, high-gloss finish.

[0132] In order to verify the effect of this invention on controlling "shear heat generation" during the injection molding process, the injection speed was deliberately increased by 20% to simulate a high-shear environment:

[0133] Comparative group performance: As the injection speed increased, the actual temperature of the melt near the hot runner gate rose sharply to over 240°C due to shear heat (the set value was 230°C), causing slight thermal degradation of the ABS material. Furthermore, the flow rate at the middle gate was much faster than that on both sides, resulting in obvious "air pockets" and severe weld lines, and the warpage deteriorated to 2.1 mm.

[0134] Example group performance: When the decision module detects an increase in injection speed and the flow channel temperature sensor shows a temperature rise trend (ΔT>2℃), the system automatically triggers the "high shear compensation strategy" in the rule base:

[0135] Immediately reduce the heating power of this area by 15%;

[0136] The opening time of the fine-tuning sequence valve is delayed by 0.05s to allow the melt front to balance.

[0137] Results: The actual melt temperature remained stable within the range of 231±1℃, no thermal degradation occurred, the flow front remained balanced, and the warpage of the final product was controlled within 0.28mm.

[0138] As can be seen from the above data, this invention, by constructing an expert rule base coupled with "heat-fluid-force" and combining it with the millisecond-level response of nanoscale sensors, achieves the following unexpected technical effects that are unattainable by existing technologies:

[0139] It breaks the mutually exclusive relationship between "speed and quality": usually increasing the injection speed will aggravate shear heat and warpage, but this invention, through a dynamic compensation mechanism, can significantly reduce warpage (optimization of 85%) while shortening the molding cycle (efficiency improvement of 14.4%).

[0140] The problem of anisotropy in long and narrow products has been solved: by using zoned differentiated pressure holding and cooling (based on laser scanning feedback), the dimensional shrinkage of long strip-shaped decorative parts tends to be consistent throughout the entire length range, and the CPK value is increased from 0.85 to 1.67, which has the stability for large-scale unmanned production.

[0141] The cumulative effect of adaptive closed loop: As the number of production cycles increases, the scrap rate shows a downward trend (rapidly converging from 1.5% in the early stage to below 0.6%), proving that the system has the ability to learn and optimize itself based on historical data.

[0142] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A decorative strip injection molding device, characterized in that, The device consists of an injection molding machine host and a mold system integrated within the host. The injection molding machine host includes a front mold section (1), a rear mold section (2), a hot runner section (3), and an ejection module (4). The front mold section (1), the rear mold section (2), and the hot runner section (3) are jointly equipped with a temperature sensor array, a pressure sensor array, and a micro pressure sensor; wherein, the temperature sensor array is distributed in the hot runner system of the hot runner section (3) and in the mold cavity formed by the front mold section (1) and the rear mold section (2), and the pressure sensor array and the micro pressure sensor are integrated in the mold cavity formed by the front mold section (1) and the rear mold section (2); The ejection module (4) includes a high-speed industrial camera and a laser scanner located at the ejection station; The mold system includes a decision module and a collaboration module. The decision module is equipped with a real-time data stream based on a multi-source sensing module and compares the data with preset process parameter thresholds and an expert rule base to generate specific process parameter adjustment instructions. The expert rule base contains multiple condition judgment rules based on the heat-flow-force coupling relationship to achieve adaptive optimization of the device. The collaboration module includes a zoned independent temperature-controlled hot runner system, a sequential valve control system with position and pressure dual feedback, and an adaptive cooling control system linked with the ejection module (4). The multi-source sensing module, central decision-making module, and collaborative execution module are interconnected through a data bus to form a closed-loop control loop, enabling adaptive optimization of parameters throughout the injection molding process. The multi-source sensing module acquires data from temperature sensor arrays and pressure sensor arrays distributed in the hot runner system and mold cavity, micro-pressure sensors integrated inside the mold, and data detected by high-speed industrial cameras and laser scanners located at the ejection station. The quantification of the heat-fluid-force coupling relationship is achieved in the following ways: the decision module inputs the raw data collected by the distributed sensors into the coupling equation for millisecond-level calculation; the thermal field quantization is based on Fourier's heat transfer law, monitors the three-dimensional temperature field distribution through a thermocouple array, and calculates the temperature gradient of the melt in the runner and cavity; the flow field quantization is based on non-Newtonian fluid mechanics combined with the viscosity variation with shear rate captured by the pressure sensor array; and the force field quantization analyzes the stress sensor data in the mold through Hooke's law to invert the internal stress generated by cooling contraction.

2. The decorative strip injection molding device according to claim 1, characterized in that, The mold system also includes a multi-source sensing module and a central processing module. The multi-source sensing module acquires data from temperature sensor arrays distributed in the hot runner system and mold cavity, pressure sensor arrays, micro-pressure sensor data integrated inside the mold, and data detected by a high-speed industrial camera and laser scanner located at the ejection station.

3. The decorative strip injection molding device according to claim 2, characterized in that, The front mold part (1) includes an upper mold (11), the upper mold (11) is provided with an injection port (12) communicating with the hot flow part (3), the upper mold (11) is also provided with a first cavity (13) adapted to the injection molded part, the first cavity (13) is provided with a pressure detection unit, which captures pressure change data at a millisecond frequency through a nanoscale piezoelectric sensor installed at a key position in the first cavity (13); The rear mold part (2) includes a lower mold (21), and the lower mold (21) is provided with a second cavity (22) corresponding to the first cavity (13). The second cavity (22) is provided with a pressure detection unit, which captures pressure change data at a millisecond frequency through a nanometer-level piezoelectric sensor at a key position of the second cavity (22). The pressure detection unit located in the first cavity (13) and the second cavity (22) can capture the pressure change data in the cavity and transmit the data to the decision module. The decision module can compare and analyze the real-time pressure data with the preset pressure curve to determine whether the filling process is balanced, and dynamically adjust the injection parameters of the heat flow section (3) according to the pressure fluctuation amplitude.

4. The decorative strip injection molding device according to claim 3, characterized in that, The hot runner (3) includes a feed inlet (31) which is connected to the injection port (12). The hot runner (3) also includes a heating chamber (32). The heating chamber (32) is equipped with a temperature monitoring unit, which collects melt temperature data in real time through multiple high-precision sensors distributed in the hot runner and mold cavity. The temperature monitoring unit, through a distributed thermocouple array arranged in an equilateral triangle in the hot runner system, can collect melt temperature data in real time at a preset sampling frequency. The decision module can compare the temperature data with a preset temperature threshold and combine it with the pressure value detected by the cavity pressure detection unit. When the temperature deviation is detected to exceed the allowable range, the heating power output is automatically adjusted to maintain the melt temperature stability.

5. The decorative strip injection molding device according to claim 4, characterized in that, The high-speed industrial camera can capture real-time images of the injection molded part surface using a multispectral light source to identify defects. The laser scanner can perform a full-range three-dimensional scan of the ejected injection molded part to obtain warpage deformation data. The decision module can comprehensively evaluate the quality of the injection molded part based on the images and scan data, and generate adjustment instructions to be fed back to the collaboration module.

6. The decorative strip injection molding device according to claim 5, characterized in that, The collaborative module includes a zoned, independently temperature-controlled hot runner system, which can implement differentiated temperature control for different areas of the mold according to the instructions of the decision module; the sequential valve control system can accurately adjust the valve needle opening timing and speed based on position and pressure dual feedback signals to ensure balanced filling of multiple gates. The decision-making module is also equipped with a feedback unit, which can adjust other modules based on the data obtained from the decision-making module. The ejection module (4) also includes an adaptive cooling control system, which can dynamically adjust the cooling water flow rate and duration according to the real-time temperature distribution data of the injection molded part; the decision module can predict the cooling effect through thermal-fluid-force coupling simulation and optimize the cooling parameters to reduce the deformation caused by internal stress.

7. A method for injection molding a decorative strip, wherein the method utilizes the decorative strip injection molding apparatus of claim 6 to perform the injection molding operation, characterized in that, Includes the following steps: S100, Parameter Initialization Stage: The historical best process parameters are loaded through the central processing module, and the injection parameters are adaptively corrected based on the characteristics of the current material batch. S200, Multi-gate Co-injection Stage: The melt state is monitored in real time by the temperature monitoring unit and pressure detection unit, and the multi-gate balanced filling is achieved by combining the sequence valve co-control module; S300, Pressure Holding and Cooling Optimization Stage: Obtain injection molded part morphology data through the laser scanner, and optimize pressure holding and cooling parameters based on the warpage prediction model output results; S400, Ejection and Verification Stage: Quality assessment is performed through the feedback unit, and when a defect is detected, process parameters are traced and the prediction model is updated.

8. The method for injection molding decorative strips according to claim 7, characterized in that, S200 includes: S210. Initial filling is performed through an open gate in the middle, and the injection pressure curve is dynamically adjusted based on real-time viscosity monitoring values. S220. When the pressure value detected by the cavity pressure sensor reaches the preset trigger threshold, the sequential valve gates on both sides are opened according to the preset timing command, and the opening degree of each valve needle is controlled based on the fixed flow ratio set in the debugging stage to maintain the balance of melt flow in multiple gates. S230 calculates the temperature rise increment caused by shear heat generation in real time and adjusts the heating power output in advance through feedforward control.

9. The method for injection molding decorative strips according to claim 7, characterized in that, The S300 includes: S310, Inversion of shrinkage stress distribution based on in-mold stress sensor data; S320: Automatically generates customized pressure holding curves based on stress distribution gradients to achieve differentiated pressure holding in different zones; S330 uses temperature field equalization technology to control the temperature gradient on the cavity surface, ensuring uniform cooling.

10. A decorative strip, said decorative strip being injection molded using a decorative strip injection molding apparatus as described in any one of claims 1-6.

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