Gas-assisted injection molding method for automotive door inner panel

Abstract

This application relates to the field of automotive door interior panel molding technology, and particularly to a gas-assisted injection molding method for automotive door interior panels. The method includes: obtaining a three-dimensional model of the cavity of an automotive door interior panel mold, and determining a high shrinkage risk region based on the three-dimensional model; determining a target holding pressure region for gas-assisted injection based on the high shrinkage risk region; obtaining a main gas penetration channel based on the target holding pressure region; performing simulation based on the main gas penetration channel to determine isolated thick-walled regions within the target holding pressure region, and determining an auxiliary gas compensation path based on the isolated thick-walled regions; obtaining a comprehensive gas injection strategy based on the main gas penetration channel and the auxiliary gas compensation path, and controlling a gas-assisted injection device to perform injection molding operations based on the comprehensive gas injection strategy. The gas-assisted injection molding method for automotive door interior panels provided by this application can solve the problem of significant isolated shrinkage caused by isolated regions formed due to differences in volume shrinkage and lateral extension characteristics.

Description

Technical Field

[0001] This application belongs to the field of automotive door inner panel molding technology, and particularly relates to a gas-assisted injection molding method for automotive door inner panel. Background Technology

[0002] The interior door panel is the core component connecting the door sheet metal to interior functional parts (armrests, speakers, ambient lighting), fulfilling both structural support (withstanding pressing loads of over 300N at the armrest) and aesthetic decoration requirements. Gas-assisted injection molding (GAIM) is an injection molding process developed for "large, complex, and lightweight plastic parts." Its core logic is to use high-pressure gas to replace part of the molten plastic, creating hollow channels inside the plastic part.

[0003] In related technologies, in large, thin-walled components such as automotive door inner panels, transverse stiffeners are usually designed to improve local rigidity. However, the thick walls of the transverse stiffeners will create a significant thickness difference with the thin walls of the panel body. As a result, during the solidification process, the melt is prone to forming an isolated area on the back of the transverse stiffeners due to the difference in volume shrinkage and the lateral extension characteristics of the transverse stiffeners. This leads to isolated shrinkage marks on the back of the transverse stiffeners caused by the significant gas pressure gradient and uneven penetration. Summary of the Invention

[0004] This application provides a gas-assisted injection molding method for automotive door inner panel, which can solve the problem that the back of the transverse reinforcing rib forms an isolated area due to volume shrinkage differences and lateral extension characteristics, resulting in isolated shrinkage marks in the back area of ​​the transverse reinforcing rib caused by significant gas pressure gradient and uneven penetration.

[0005] In a first aspect, embodiments of this application provide a gas-assisted injection molding method for an automotive door inner panel, comprising:

[0006] A three-dimensional model of the cavity of the automotive door inner panel mold is obtained, and a high shrinkage risk area is determined based on the three-dimensional model of the cavity; wherein, the transition rounded corner area between the transverse reinforcing rib and the panel body is marked in the three-dimensional model of the cavity;

[0007] The target pressure holding area for gas-assisted injection is determined based on the high shrinkage risk region; wherein, the target pressure holding area is used to indicate the location where pressure needs to be held during gas-assisted injection;

[0008] The main gas penetration channel is obtained based on the target pressure holding area; wherein, the main gas penetration channel is a medium-air channel formed inside the thick wall after the high-pressure gas pushes the unsolidified melt away from the center;

[0009] Based on the main gas penetration channel, a simulation is performed to determine the isolated thick-walled region within the target pressure-holding area, and an auxiliary gas compensation path is determined according to the isolated thick-walled region; wherein, the endpoint of the auxiliary gas compensation path is located on one side of the main gas penetration channel;

[0010] A comprehensive gas injection strategy is obtained based on the main gas penetration channel and the auxiliary gas compensation path, and the gas-assisted injection device is controlled to perform injection molding operation based on the comprehensive gas injection strategy.

[0011] The gas-assisted injection molding method for automotive door inner panel provided in this application involves obtaining a three-dimensional model of the cavity of the automotive door inner panel mold and determining a high shrinkage risk region based on the three-dimensional model; determining the target holding pressure area for gas-assisted injection based on the high shrinkage risk region; obtaining the main gas penetration channel based on the target holding pressure area, and then simulating based on the main gas penetration channel to determine isolated thick-walled areas within the target holding pressure area, and determining the auxiliary gas compensation path based on the isolated thick-walled areas; obtaining a comprehensive gas injection strategy based on the main gas penetration channel and the auxiliary gas compensation path, and controlling the gas-assisted injection device to perform injection molding operations based on the comprehensive gas injection strategy. This method, by accurately determining the high shrinkage risk region, can identify areas where shrinkage may occur in advance. The target holding pressure area determined based on the high shrinkage risk region ensures that the gas can be concentrated in the key parts that require holding pressure during the injection process, further reducing the occurrence of shrinkage. Furthermore, the main gas penetration channel obtained from the target pressure holding area, along with the isolated thick-walled region and auxiliary gas compensation path determined by simulation based on the main gas penetration channel, together constitute a comprehensive gas injection strategy. This allows the gas to be distributed more evenly during the injection process, thereby solving the problem of isolated shrinkage marks caused by significant gas pressure gradients and uneven penetration in the back area of ​​the transverse reinforcing ribs due to volume shrinkage differences and lateral extension characteristics.

[0012] Secondly, embodiments of this application provide a gas-assisted injection molding system for automotive door inner panel, comprising:

[0013] The acquisition unit is used to acquire a three-dimensional model of the cavity of the automotive door inner panel mold, and to determine the high shrinkage risk area based on the three-dimensional model of the cavity; wherein, the transition rounded corner area between the transverse reinforcing rib and the panel body is marked in the three-dimensional model of the cavity;

[0014] A determining unit is configured to determine a target pressure-holding area for gas-assisted injection based on the high shrinkage risk region; wherein the target pressure-holding area is used to indicate the location where pressure needs to be held during gas-assisted injection;

[0015] The processing unit is used to obtain the main gas penetration channel according to the target pressure holding area; wherein, the main gas penetration channel is a medium-air channel formed inside the thick wall after the high-pressure gas pushes the unsolidified melt away from the center;

[0016] An analysis unit is used to perform simulations based on the main gas penetration channel, determine isolated thick-walled regions within the target pressure-holding area, and determine auxiliary gas compensation paths based on the isolated thick-walled regions; wherein the endpoint of the auxiliary gas compensation path is located on one side of the main gas penetration channel;

[0017] The result unit is used to obtain a comprehensive gas injection strategy based on the main gas penetration channel and the auxiliary gas compensation path, and to control the gas-assisted injection device to perform injection molding operation based on the comprehensive gas injection strategy.

[0018] Thirdly, embodiments of this application provide a gas-assisted injection molding apparatus for automotive door interior panels, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is executed by the processor, it implements the method described in any of the first aspects above.

[0019] Fourthly, embodiments of this application provide a computer program product that, when run on a gas-assisted injection molding equipment for automotive door interior panels, causes the equipment to perform the gas-assisted injection molding method for automotive door interior panels as described in any of the first aspects above.

[0020] It is understood that the beneficial effects of the second to fourth aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic flowchart of a gas-assisted injection molding method for an automotive door inner panel according to an embodiment of this application;

[0023] Figure 2 This is a schematic diagram of the implementation process of step S300 in the gas-assisted injection molding method for automotive door inner panel provided in an embodiment of this application;

[0024] Figure 3This is a schematic diagram of the implementation process of step S400 in the gas-assisted injection molding method for automotive door inner panel provided in an embodiment of this application;

[0025] Figure 4 This is a schematic diagram of the implementation process of step S500 in the gas-assisted injection molding method for an inner panel of an automobile door provided in an embodiment of this application;

[0026] Figure 5 This is a schematic diagram of the implementation process of step S520 in the gas-assisted injection molding method for automotive door inner panel provided in an embodiment of this application;

[0027] Figure 6 This is a schematic diagram of the implementation process of step S100 in the gas-assisted injection molding method for an inner panel of an automobile door provided in an embodiment of this application;

[0028] Figure 7 This is a schematic diagram of the gas-assisted injection molding system for automotive door inner panel provided in this application embodiment;

[0029] Figure 8 This is a schematic diagram of the control device provided in the embodiments of this application. Detailed Implementation

[0030] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0031] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0032] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0033] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0034] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0035] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0036] The interior door panel is the core component connecting the door sheet metal with interior functional parts (armrests, speakers, ambient lighting), fulfilling both structural support and aesthetic requirements. Gas-assisted injection molding (GAIM) is an injection molding process developed for "large, complex, and lightweight plastic parts." Its core logic is to use high-pressure gas to replace part of the molten plastic, creating hollow channels inside the plastic part.

[0037] In related technologies, in large, thin-walled components such as automotive door inner panels, transverse stiffeners are usually designed to improve local rigidity. However, the thick walls of the transverse stiffeners will create a significant thickness difference with the thin walls of the panel body. As a result, during the solidification process, the melt is prone to forming an isolated area on the back of the transverse stiffeners due to the difference in volume shrinkage and the lateral extension characteristics of the transverse stiffeners. This leads to isolated shrinkage marks on the back of the transverse stiffeners caused by the significant gas pressure gradient and uneven penetration.

[0038] To address the aforementioned issues, this application provides a gas-assisted injection molding method for automotive door inner panel panels. This method involves acquiring a three-dimensional model of the cavity of the automotive door inner panel mold and determining a high-shrinkage-mark risk region based on the model; determining the target holding pressure area for gas-assisted injection based on the high-shrinkage-mark risk region; obtaining the main gas penetration channel based on the target holding pressure area; simulating the main gas penetration channel to determine isolated thick-walled regions within the target holding pressure area; and determining the auxiliary gas compensation path based on the isolated thick-walled regions; obtaining a comprehensive gas injection strategy based on the main gas penetration channel and the auxiliary gas compensation path; and controlling the gas-assisted injection device to perform the injection molding operation based on the comprehensive gas injection strategy. This method, by accurately determining the high-shrinkage-mark risk region, can identify areas where shrinkage marks may occur in advance. The target holding pressure area determined based on the high-shrinkage-mark risk region ensures that the gas is concentrated in the critical areas requiring holding pressure during injection, further reducing the occurrence of shrinkage marks. Furthermore, the main gas penetration channel obtained from the target pressure holding area, along with the isolated thick-walled region and auxiliary gas compensation path determined by simulation based on the main gas penetration channel, together constitute a comprehensive gas injection strategy. This allows the gas to be distributed more evenly during the injection process, thereby solving the problem of isolated shrinkage marks caused by significant gas pressure gradients and uneven penetration in the back area of ​​the transverse reinforcing ribs due to volume shrinkage differences and lateral extension characteristics.

[0039] The gas-assisted injection molding method for automotive door interior panels provided in this application embodiment can be applied to a gas-assisted injection molding equipment for automotive door interior panels. In this case, the gas-assisted injection molding equipment for automotive door interior panels is the executing entity of the gas-assisted injection molding method for automotive door interior panels provided in this application embodiment. This application embodiment does not impose any restrictions on the specific type of gas-assisted injection molding equipment for automotive door interior panels.

[0040] For example, a gas-assisted injection molding equipment for automotive door interior panels includes a gas-assisted injection molding device and a control device; wherein the gas-assisted injection molding device and the control device are communicatively connected; the gas-assisted injection molding device for automotive door interior panels includes a gas injection unit, a mold unit, and a melt delivery unit; the gas injection unit is used to inject high-pressure gas into the mold unit to realize the gas-assisted injection molding process; the gas injection unit may be composed of components such as a high-pressure gas source, a gas control valve, and a gas delivery pipeline, the high-pressure gas source provides stable high-pressure gas, the gas control valve precisely regulates the gas flow and pressure, and the gas delivery pipeline accurately delivers the high-pressure gas to the designated position of the mold unit. The mold unit has a cavity for molding the automotive door interior panel, and the structure of the cavity is adapted to the shape of the automotive door interior panel; the mold unit may be composed of a fixed mold and a moving mold, the fixed mold is fixed on the fixed template of the injection molding machine, and the moving mold is installed on the moving template of the injection molding machine, and the closing and opening of the fixed mold and the moving mold are realized by a mold closing mechanism. In the cavity design of the mold unit, the transition rounded corner area between the transverse reinforcing ribs and the protective plate body is treated to optimize the wall thickness transition in this area, thereby reducing the difference in melt flow resistance and lowering the risk of shrinkage marks caused by abrupt changes in wall thickness. The melt delivery unit is used to transport the plastic melt into the cavity of the mold unit. The melt delivery unit can be composed of components such as a screw extruder, a barrel, and a nozzle. The screw extruder conveys the plastic raw material forward and melts it through the rotating screw. The barrel provides a heating and heat-preserving environment for the plastic melt, allowing the melt to reach a suitable injection temperature. The nozzle injects the melt into the cavity of the mold unit at a certain pressure and speed. The relationship between the injection molding machine, gas injection unit, mold unit, and melt delivery unit is as follows: Specifically, the injection molding machine provides rotational power to the screw extruder through its internal hydraulic or electric system, driving the screw to rotate and achieve the delivery and melting of plastic raw materials. Simultaneously, the injection molding machine controls the opening and closing of the nozzle, as well as the pressure and speed of the melt injection into the mold cavity, ensuring the melt fills the mold cavity in a stable state. Furthermore, the injection molding machine works closely with the gas injection unit, using precise timing control to inject high-pressure gas at the appropriate moment after the melt fills the cavity, thus completing the gas-assisted injection molding process. The mold unit is installed on the fixed and moving mold plates of the injection molding machine, precisely closing and opening. The control device can be a computer, PC, tablet, laptop, netbook, desktop computer, smart screen, or industrial controller, etc.

[0041] To better understand the gas-assisted injection molding method for automotive door inner panel provided in this application, the specific implementation process of the gas-assisted injection molding method for automotive door inner panel provided in this application will be described below by way of example.

[0042] Figure 1This illustration shows a schematic flowchart of a gas-assisted injection molding method for automotive door inner panel provided in an embodiment of this application. The gas-assisted injection molding method for automotive door inner panel includes:

[0043] S100: Obtain the 3D model of the cavity of the car door inner panel mold, and determine the high shrinkage risk area based on the 3D model of the cavity; wherein, the transition rounded corner area between the transverse reinforcing rib and the panel body is marked in the 3D model of the cavity.

[0044] It can be understood that the 3D model of the cavity is a digital model reflecting the internal shape and structural dimensions of the cavity in the mold for the inner panel of an automotive door. It includes all cavity features such as the panel body, transverse reinforcing ribs, and transition rounded corner areas. Transverse reinforcing ribs are raised features arranged laterally along the cavity to enhance the structural strength of the inner panel. The panel body is the main load-bearing structure of the inner panel, and the transition rounded corner area is the arc-shaped transition part where the transverse reinforcing ribs connect to the panel body (to avoid stress concentration at right angles). The high-risk area for shrinkage marks is the region in the cavity where uneven cooling and shrinkage of the plastic melt due to differences in wall thickness easily leads to surface depressions (shrinkage marks).

[0045] For example, the 3D model of the cavity can be obtained by retrieving the original CAD design file (e.g., UG, CATIA format); or, in the absence of the original file, a 3D laser scanning device can be used to scan the solid cavity, obtain point cloud data, and then use Geomagic Studio software to perform reverse reconstruction to obtain a complete 3D model of the cavity.

[0046] In one possible implementation, please refer to Figure 6 S100, Obtain the 3D model of the cavity of the automotive door inner panel mold, and determine the high shrinkage risk region based on the 3D model of the cavity, including:

[0047] S110, based on the position of the horizontal reinforcing rib, performs thickness gradient analysis on the transition rounded corner area to obtain the thickness ratio of the maximum wall thickness to the average wall thickness of the adjacent area.

[0048] Thickness gradient analysis is understood to be a process of continuously measuring the wall thickness in the transition fillet area and surrounding regions to analyze the wall thickness variation patterns. The maximum wall thickness is the largest dimension measured within the transition fillet area (due to the fillet transition, the wall thickness in this area is usually greater than that of the main body of the protective plate). The average wall thickness of adjacent areas is the average wall thickness within a certain range (usually 2-3 times the fillet radius) extending outward from the transition fillet area. The thickness ratio is the ratio of the maximum wall thickness to this average wall thickness, used to quantify the degree of wall thickness difference.

[0049] For example, in the 3D model of the cavity, all marked transition fillet areas are located. Using the centerline of the horizontal reinforcing rib as a reference, uniformly distributed measurement points are set along the arc direction of the transition fillet area and perpendicular to the reinforcing rib. Starting from the outer edge of the transition fillet area, an area extending outwards by twice the fillet radius is designated as the adjacent area, and uniformly distributed measurement points are set there as well. The wall thickness data of all measurement points are recorded one by one. The maximum value within the transition fillet area is selected as the maximum wall thickness. The arithmetic mean of the wall thicknesses of all measurement points in the adjacent area is calculated as the average wall thickness of the adjacent area. Finally, the maximum wall thickness is divided by the average wall thickness of the adjacent area to obtain the thickness ratio.

[0050] S120, when the thickness ratio is greater than the preset shrinkage threshold, the transition rounded corner area is defined as a high shrinkage risk area.

[0051] It is understandable that the preset shrinkage threshold is a critical value determined based on the characteristics of the plastic material and the molding process parameters. When the thickness ratio exceeds this value, the probability of uneven cooling and shrinkage of the plastic melt will increase significantly, and shrinkage defects will be difficult to avoid. Different plastic materials have different thresholds. For example, the preset shrinkage threshold for PP (polypropylene) is usually 1.5-2.0, and for ABS it is usually 1.4-1.8.

[0052] For example, based on the actual material used in the inner panel of the car door (e.g., PP + glass fiber), the corresponding preset shrinkage threshold is retrieved from the material database (if there is no readily available data, it can be determined through small-batch experiments: prepare samples with different thickness ratios, test the critical thickness ratio for shrinkage, and use this value as the threshold). The thickness ratio is compared with the preset shrinkage threshold. If the thickness ratio is greater than the threshold, the transition rounded corner area is marked in the 3D model of the cavity, which is the high shrinkage risk area. Then, the high shrinkage risk area is accurately screened through threshold comparison, reducing the ineffective processing of areas with no shrinkage risk or low risk, and improving the targeting and efficiency of subsequent gas channel design.

[0053] In one possible implementation, please refer to Figure 6 S100, the method also includes,

[0054] S120A generates prompt data when the thickness ratio is less than the preset shrinkage threshold; the prompt data is used to indicate that no auxiliary gas compensation path is required.

[0055] For example, when comparing the thickness ratio with a preset shrinkage threshold, if the comparison result is that the thickness ratio is less than the preset shrinkage threshold, prompt data is generated. By generating clear prompt data, unnecessary auxiliary gas channel design steps can be skipped directly, simplifying the overall process.

[0056] S200, the target pressure holding area for gas-assisted injection is determined based on the high shrinkage risk domain; wherein, the target pressure holding area is used to indicate the part that needs to be pressure held during the gas-assisted injection process.

[0057] For example, when specifically determining the target pressure holding area, the shape, size, and distribution location of the high-risk area for shrinkage marks are considered, along with the pressure distribution value of the gas-assisted injection device, to match the target pressure holding area with the gas pressure distribution, thereby determining the target pressure holding area. For instance, for a high-risk area for shrinkage marks with a relatively regular shape, the entire area can be used as the target pressure holding area.

[0058] In one possible implementation, S200, the target holding pressure region for gas-assisted injection is determined based on the high shrinkage risk region, including:

[0059] S210, determine the center point of the high shrinkage risk area, and take the center point as the center of the sphere and the length of X times the wall thickness of the protective plate as the radius to obtain the spherical pressure-holding envelope.

[0060] It can be understood that the center point is the geometric center of the high-shrinkage risk area, obtained by calculating the average of the coordinates of all vertices in that area; X times the wall thickness of the protective plate body is a radius coefficient set based on the pressure holding range requirements. The value of X can be determined by combining the wall thickness of the protective plate body and the size of the high-shrinkage risk area (ensuring that the spherical surface can completely cover the risk area and the necessary surrounding areas). The spherical pressure holding envelope is a spherical covering surface surrounding the high-shrinkage risk area, used to define the spatial range of pressure holding.

[0061] For example, by selecting a single high shrinkage risk area in the 3D model of the cavity, and then obtaining the center point using the coordinates of all vertices of the area, the average wall thickness of the protective plate body is measured, and the X value is set according to the material and the size of the risk area. Then, the radius r is calculated, and a spherical pressure-holding envelope surface is generated with the center point as the center and r as the radius (this spherical surface fits the internal structure of the cavity; if it conflicts with other parts, it can be modified by adjusting the X value so that the spherical surface does not penetrate the decorative surface of the protective plate). In addition, if there are multiple independent high shrinkage risk areas, corresponding spherical pressure-holding envelope surfaces need to be generated separately.

[0062] S220, the back area of ​​the transverse reinforcing rib covered by the spherical pressure-holding envelope and the adjacent guard plate body are defined as the target pressure-holding area.

[0063] It can be understood that the back area of ​​the horizontal reinforcing rib refers to the side of the horizontal reinforcing rib away from the main channel of the plastic melt (the melt filling and cooling rate in this area is slower, and shrinkage marks are more likely to occur), and the adjacent guard plate body is the part of the guard plate body covered by the spherical pressure holding envelope (directly connected to the high shrinkage mark risk area).

[0064] For example, a spherical pressure-holding envelope is displayed in the 3D model of the cavity, and the intersection area between the spherical surface and the internal structure of the cavity is determined. First, the back area of ​​the transverse reinforcing rib in the intersection is identified, that is, by observing the melt flow direction, the front (towards the main channel) and back (away from the main channel) of the reinforcing rib are determined, and the intersection part of the back is selected; then, the adjacent guard plate body in the intersection is identified, that is, the guard plate body structure other than the reinforcing rib is selected, so that this part is directly connected to the high shrinkage risk area, and then the two parts are merged to form a closed target pressure-holding area.

[0065] This configuration, through precise screening of the pressure-holding area using a spherical envelope, ensures that the target pressure-holding area covers both core risk points and excludes irrelevant thin-walled areas, thereby improving pressure-holding efficiency. At the same time, it clearly distinguishes the back of the reinforcing rib from the adjacent body, providing a basis for the subsequent design of the gas channel routing.

[0066] S300, the main gas penetration channel is obtained according to the target pressure holding area; the main gas penetration channel is the air channel formed inside the thick wall after the high-pressure gas pushes the unsolidified melt away from the center.

[0067] It is understandable that the main gas penetration channel is used to deliver high-pressure gas to the core of the target pressure-holding area. Its function is to supplement the cooling and contraction of the melt through gas pressure and suppress the formation of shrinkage marks.

[0068] For example, by first marking the last solidified part of the melt within the target pressure holding area, and then locating the center of the injection gate, the path from the center of the gate to the last solidification point is taken as the basic path, so that the path is completely located inside the thick wall of the target pressure holding area, thereby forming a three-dimensional model of the main gas penetration channel.

[0069] In one possible implementation, please refer to Figure 2 S300, based on the target pressure holding area, obtains the main gas penetration channel, including:

[0070] S310, within the target pressure holding area, starting from the center of the gate and ending at the final solidification point of the high shrinkage risk zone, and based on the starting and ending points, determine the preliminary gas channel axis.

[0071] It can be understood that the final solidification point is the node where the plastic melt finally cools and solidifies within the target pressure holding area. The initial gas channel axis is a straight line or smooth curve connecting the start and end points.

[0072] For example, in the three-dimensional model of the cavity, by locating the center position of the injection gate, which is the entrance for the plastic melt to enter the cavity, the final solidification point of the melt in the high shrinkage risk area is determined based on the material characteristics and cooling conditions of the high shrinkage risk area. Then, with the center of the gate as the starting point and the final solidification point of the high shrinkage risk area as the ending point, the preliminary gas channel axis can be determined inside the thick wall of the target pressure holding area.

[0073] S320 uses the initial gas channel axis as a basis and optimizes the path within the target pressure holding area according to the optimization requirements to obtain the optimization result. The optimization requirements are that the optimized channel path should maintain a certain distance in space from the cooling water channel in the mold and the key edges of the product appearance. The overall direction of the optimized channel path is parallel to the flow direction of the plastic melt from the gate to the final solidification point.

[0074] For example, by identifying the cooling water channels and key edge features of the product appearance in the three-dimensional model of the cavity, marking the spatial position and size, and then determining the distance between the axis and the cooling water channels and key edge features based on the initial gas channel axis, and then adjusting the overall direction of the axis so that the angle between it and the melt flow direction is ≤15°, the optimized channel path is finally obtained.

[0075] S330, the main gas penetration channel is determined based on the optimization results; wherein, the minimum distance between the main gas penetration channel and the decorative surface of the protective panel is not less than the thickness of the cured layer in the transition rounded corner area.

[0076] For example, based on the optimized channel path in the 3D model of the cavity, the shortest distance between the channel axis and the decorative surface of the protective plate is determined. First, the thickness of the cured layer in the transition rounded corner area is determined by experiment. If the distance between a certain point of the channel and the decorative surface is found to be only 1mm, then the channel segment is shifted into the cavity until the minimum distance of all points is ≥1.5mm to determine the channel diameter. Then, with the optimized axis as the center, the cylindrical air channel outline can be determined, and finally the main gas penetration channel is generated.

[0077] This design ensures that the main gas penetration channel will not damage the decorative surface of the protective plate, while also ensuring that the channel is located inside the thick wall, so that the gas pressure can effectively act on the melt contraction area.

[0078] S400, based on the main gas penetration channel, simulates and determines the isolated thick-walled region within the target pressure-holding area, and determines the auxiliary gas compensation path based on the isolated thick-walled region; wherein, the endpoint of the auxiliary gas compensation path is located on one side of the main gas penetration channel.

[0079] For example, based on the main gas penetration channel, a simulation is performed within the target pressure-holding area to obtain the steady-state gas pressure value within the target pressure-holding area. Then, based on the steady-state gas pressure value, a low-pressure stagnation area is determined where the gas pressure is less than that of the main channel area and the wall thickness is greater than the average wall thickness of the protective plate body. The low-pressure stagnation area is identified as an isolated thick-walled area. The spatial location of the isolated thick-walled area and the main gas penetration channel are analyzed to obtain the orientation result. Based on the orientation result, an auxiliary gas compensation path is determined on the main gas penetration channel.

[0080] In one possible implementation, S400, based on simulation of the main gas penetration channel, identifies isolated thick-walled regions within the target pressure-holding area, including:

[0081] S410, based on the main gas penetration channel, performs gas pressure field simulation within the target pressure holding region to obtain the steady-state gas pressure value within the target pressure holding region.

[0082] For example, during the simulation, the inlet pressure of the main gas penetration channel is set to the actual process parameter, the temperature is consistent with the melt filling temperature, the simulation time is set to the complete cycle of the gas holding stage, and then the gas pressure data of all nodes in the target holding area are extracted to generate a steady-state gas pressure value containing numerical and location information.

[0083] S420 determines the low-pressure stagnation area based on the steady-state gas pressure value, where the gas pressure is less than that of the main channel area and the wall thickness is greater than that of the average wall thickness of the protective plate body, and classifies the low-pressure stagnation area as an isolated thick-walled area.

[0084] For example, by comparing the steady-state gas pressure values ​​of each region within the target pressure-holding area, regions with gas pressures lower than the gas pressure threshold of the main gas penetration channel are selected. Simultaneously, the wall thickness of these regions is measured, and regions with wall thicknesses greater than the average wall thickness of the protective plate body are marked. These regions, which simultaneously satisfy both low gas pressure and large wall thickness, are low-pressure stagnation regions, i.e., isolated thick-walled regions. This selection method allows for precise location of areas prone to defects such as shrinkage marks during molding due to insufficient gas pressure and large wall thickness, providing an accurate basis for determining subsequent auxiliary gas compensation paths.

[0085] In one possible implementation, please refer to Figure 3 S400, and determine the auxiliary gas compensation path based on the isolated thick-walled region, including:

[0086] S410 A, the spatial location of the isolated thick-walled region and the main gas penetration channel are analyzed to obtain the orientation result; wherein, the orientation result is used to indicate the positional relationship of the isolated thick-walled region relative to the main gas penetration channel.

[0087] It can be understood that relative orientation refers to the spatial position of an isolated thick-walled region relative to the main gas penetration channel, as well as the distance between the two.

[0088] For example, by determining the axial direction of the main gas penetration channel, then calculating the geometric center coordinates of the isolated thick-walled region and the center coordinates of the main channel axis, and then comparing the coordinate data to obtain the relative positional relationship; then measuring the shortest straight-line distance between the geometric center of the isolated thick-walled region and the main channel axis, the final orientation result is obtained.

[0089] S420A determines the sidewall point of the geometric center of the isolated thick-walled region on the main gas penetration channel based on the orientation results, and uses the sidewall point as the starting connection point of the auxiliary gas compensation path.

[0090] It can be understood that the sidewall point is the point on the sidewall of the main gas penetration channel where the line connecting it to the geometric center of the isolated thick-walled region is perpendicular to the axis of the main channel (this point is the closest point on the main channel to the isolated thick-walled region, enabling gas to be transported over the shortest distance). The starting connection point is the connection point between the auxiliary gas compensation path and the main gas penetration channel, allowing the gas in the auxiliary channel to be directly obtained from the main channel.

[0091] For example, based on the orientation results, a point with the same X and Z coordinates as the geometric center of the isolated thick-walled region is determined on the axis of the main gas penetration channel. The coordinates of this point on the axis of the main channel are obtained. Then, a perpendicular line is drawn from the geometric center of the isolated thick-walled region to the axis of the main channel. The intersection of the perpendicular line and the sidewall of the main channel is the sidewall point.

[0092] S430A determines a straight line or curve from the starting connection point toward the geometric center of the isolated thick-walled region, and uses the straight line or curve as the auxiliary gas compensation path.

[0093] For example, based on the spatial structure between the starting connection point and the geometric center of the isolated thick-walled region, if there is no obstruction between them, a straight line from the starting connection point to the geometric center of the isolated thick-walled region is determined, and the path diameter can be set to 2 mm; if there is a small reinforcing rib obstructing between them, a smooth curve can be determined, that is, starting from the starting connection point, going around the side of the reinforcing rib, and then extending to the geometric center of the isolated thick-walled region. The radius of curvature of the curve is ≥10 mm, and the path diameter is still 2 mm. Then check whether the path is completely located inside the thick wall of the target pressure-holding area and whether it conflicts with other cavity features. After confirming that there are no errors, the straight line or curve is determined as the auxiliary gas compensation path.

[0094] With this configuration, the auxiliary gas compensation path can deliver gas to isolated thick-walled areas with the shortest distance and least resistance, ensuring that the area receives sufficient pressure replenishment. At the same time, the design of the path size and orientation can avoid conflicts with other structures, ensuring the feasibility of mold processing.

[0095] S500 obtains a comprehensive gas injection strategy based on the main gas penetration channel and the auxiliary gas compensation path, and controls the gas-assisted injection device to perform injection molding operation based on the comprehensive gas injection strategy.

[0096] For example, the integrated gas injection strategy is a complete execution plan that integrates the path information of the main channel and auxiliary channel, as well as parameters such as gas injection timing, pressure, and duration. It can be achieved by first spatially integrating the three-dimensional models of the main gas penetration channel and the auxiliary gas compensation path to determine their relative positions and connection points. Then, based on the location of the connection points, the gas injection timing is calculated. The injection pressure and duration of both are set according to the pressure holding requirements. This information is then integrated into a comprehensive gas injection strategy (which may include path coordinates, timing tables, pressure parameters, and duration). Finally, the gas-assisted injection device is controlled to perform injection molding operations according to the comprehensive gas injection strategy.

[0097] In one possible implementation, please refer to Figure 4 S500, based on the main gas penetration channel and the auxiliary gas compensation path, obtains a comprehensive gas injection strategy, and based on the comprehensive gas injection strategy, controls the gas-assisted injection device to perform injection molding operations, including:

[0098] S510, Spatial integration is performed on the main gas penetration channel and the auxiliary gas compensation path to obtain the spatial integration result; wherein, the spatial integration result includes the relative positional relationship and intersection position between the main gas penetration channel and the auxiliary gas compensation path, and the intersection position refers to the intersection of the starting connection point and the side wall of the main gas penetration channel.

[0099] It can be understood that spatial integration is the process of superimposing the three-dimensional models of the main channel and the auxiliary channel to obtain their relationship in space; the relative positional relationship includes whether they are parallel, the size of the included angle, the spacing, etc.; the intersection point is the intersection of the starting connection point of the auxiliary channel and the side wall of the main channel.

[0100] For example, the models of the main gas penetration channel and the auxiliary gas compensation path are imported into the same coordinate system. The software's measurement and positioning functions are used to determine the relative positional relationship between the two, such as whether the included angle is within a reasonable range (generally, the included angle should be less than 30° to ensure smooth gas flow). At the same time, the minimum distance between the two is measured to ensure that the distance is greater than the minimum safe distance for mold processing. Then, the intersection position of the starting connection point of the auxiliary gas compensation path and the side wall of the main gas penetration channel is determined, and the coordinate information of the intersection point is recorded, thus forming a spatial integration result.

[0101] S520, based on spatial integration results, determines the timing sequence of gas injection.

[0102] For example, based on the relative positions and intersections of the main gas penetration channel and the auxiliary gas compensation path in the spatial integration results, the start time of injection for the main gas penetration channel is determined. Since the main channel is the primary gas delivery path, injection is initiated first to quickly establish a base pressure in the target pressure-holding area. Then, based on the connection between the auxiliary gas compensation path and the main channel, as well as the location of the isolated thick-walled region, the start time of injection for the auxiliary gas compensation path is determined. This can be done after the main channel has been injected for a period of time and the target pressure-holding area has a certain pressure base, by then initiating injection for the auxiliary channel to ensure precise gas delivery to the isolated thick-walled region. Simultaneously, based on the gas flow velocity within the channel and the channel length and diameter, the time it takes for the gas to reach each key location can be estimated, thereby determining the timing sequence of each stage in the entire gas injection process, forming a complete gas injection timing sequence. Furthermore, the timing sequence is set to first inject high-pressure gas into the main gas penetration channel, allowing the gas to penetrate along the main channel to the core area of ​​the target pressure-holding region. After the gas pressure in the main gas penetration channel reaches a stable value, compensation gas is then injected sequentially into the auxiliary gas compensation path.

[0103] In one possible implementation, please refer to Figure 5 S520, based on spatial integration results, determines the time sequence of gas injection, including:

[0104] S521, determine the flow path distance from the starting connection point along the main gas penetration channel to the gas injection gate based on the intersection position and relative position relationship; wherein, the flow path distance is the distance that the gas needs to travel in the main gas penetration channel.

[0105] For example, based on the coordinates of the starting connection point and the gas injection gate recorded in the spatial integration results, the straight-line distance from the starting connection point along the axis of the main gas penetration channel to the gas injection gate is calculated, and this distance is the flow channel distance. If there is a curved part in the main gas penetration channel, the measurement is performed in segments according to the actual centerline trajectory of the channel and the measurements are accumulated to obtain the accurate flow channel distance.

[0106] S522, the delay time and flow time are calculated based on the flow channel distance; where the delay time is used to indicate the time that the gas needs to wait before it can start flowing from the starting connection point, and the flow time is used to indicate the time required for the gas to flow from the starting connection point to the gas injection gate.

[0107] For example, the flow rate of the gas in the main channel can be set (which can be set according to the gas type and pressure, for example, the flow rate of nitrogen at a pressure of 10 MPa is about 50 mm / s); the flow time can be calculated based on the channel distance, which is the channel distance divided by the gas flow rate; and the delay time can be set to 75% of the flow time to ensure that the main channel forms a stable pressure at the starting connection point.

[0108] S523, sort the delay time and flow time to obtain the time sequence of gas injection.

[0109] For example, the delay time and flow time corresponding to each starting connection point on the main gas penetration channel are arranged in chronological order. In the case of multiple starting connection points, they are sorted according to their position on the main channel and the order of gas flow. For example, the time sequence corresponding to the starting connection point that arrives at the gas injection gate first is placed first, thus forming a complete gas injection timing sequence. This sequence clearly defines the time when the gas starts flowing at each starting connection point and the time when it arrives at the gas injection gate, providing a key basis for subsequent precise control of gas injection.

[0110] S530, adjust the gas injection parameters; the gas injection parameters include gas injection pressure and injection duration, and the gas injection pressure of the main gas penetration channel is set to be higher than the gas injection pressure of the auxiliary gas compensation path.

[0111] It's understandable that gas injection pressure is the high-pressure gas pressure in the injection channel. Injection duration is the time the gas maintains that pressure. The main channel pressure is higher than the auxiliary channel pressure because the main channel needs to cover a larger pressure-holding area, requiring higher pressure to ensure gas penetration. The auxiliary channel only covers a localized, isolated area, so lower pressure is sufficient to meet the requirements, avoiding localized deformation caused by high pressure.

[0112] For example, based on the pressure holding requirements and mold structure characteristics, the gas injection pressure of the main gas penetration channel is first determined and set to a pressure value that can quickly establish a stable gas pressure in the target pressure holding area without damaging the mold and product. Since the auxiliary gas compensation path mainly provides precise pressure holding supplementation for isolated thick-walled areas, its gas injection pressure can be relatively low to ensure that the gas can be smoothly delivered to the target area without causing other adverse effects due to excessive pressure. Regarding the injection duration, the injection duration of the main gas penetration channel should ensure that the entire target pressure holding area achieves sufficient pressure holding effect. This can be set according to the mold size and plastic melt characteristics. The injection duration of the auxiliary gas compensation path can be determined based on the size of the isolated thick-walled area and the required pressure holding amount.

[0113] S540 generates a comprehensive gas injection strategy based on the timing sequence and gas injection parameters, and controls the gas-assisted injection device to perform injection molding operation based on the comprehensive gas injection strategy.

[0114] For example, each time point in the time sequence is matched with gas injection parameters. For instance, after the delay time corresponding to the starting connection point of the main gas penetration channel, gas is injected at a set higher injection pressure and maintained for the corresponding injection duration. For the auxiliary gas compensation path, gas is injected at a lower injection pressure at its corresponding starting time point and maintained for the set time. These matched time, pressure, and duration information are integrated to form a comprehensive gas injection strategy, and then the gas-assisted injection device is controlled to perform injection molding operations according to the comprehensive gas injection strategy.

[0115] This design allows the gas to be distributed more evenly during injection, thus resolving the issue of isolated areas formed on the back of the transverse reinforcing ribs due to differences in volume shrinkage and lateral extension characteristics. This, in turn, prevents isolated shrinkage marks caused by significant gas pressure gradients and uneven penetration in the back area of ​​the transverse reinforcing ribs.

[0116] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0117] Corresponding to the gas-assisted injection molding method for automotive door interior panels described in the above embodiments, this application also provides a gas-assisted injection molding system for automotive door interior panels, wherein each unit of the system can realize each step of the gas-assisted injection molding method for automotive door interior panels. Figure 7 The diagram shows a structural block diagram of a gas-assisted injection molding system for automotive door inner panel provided in an embodiment of this application. For ease of explanation, only the parts related to the embodiments of this application are shown.

[0118] Reference Figure 7 The gas-assisted injection molding system for the interior door panel of this car includes:

[0119] The acquisition unit is used to acquire the three-dimensional model of the cavity of the car door inner panel mold and determine the high shrinkage risk area based on the three-dimensional model of the cavity; wherein, the transition rounded corner area between the transverse reinforcing rib and the panel body is marked in the three-dimensional model of the cavity;

[0120] A determining unit is used to determine the target pressure holding area for gas-assisted injection based on a high shrinkage risk region; wherein, the target pressure holding area is used to indicate the location where pressure needs to be held during gas-assisted injection;

[0121] The processing unit is used to obtain the main gas penetration channel according to the target pressure holding area; wherein, the main gas penetration channel is the air channel formed inside the thick wall after the high-pressure gas pushes the unsolidified melt away from the center;

[0122] The analysis unit is used to perform simulations based on the main gas penetration channel, identify isolated thick-walled regions within the target pressure-holding area, and determine the auxiliary gas compensation path based on the isolated thick-walled regions; wherein, the endpoint of the auxiliary gas compensation path is located on one side of the main gas penetration channel;

[0123] The result unit is used to obtain a comprehensive gas injection strategy based on the main gas penetration channel and the auxiliary gas compensation path, and to control the gas-assisted injection device to perform injection molding operation based on the comprehensive gas injection strategy.

[0124] It should be noted that the information interaction and execution process between the above systems / units are based on the same concept as the method embodiments of this application. For details on their specific functions and technical effects, please refer to the method embodiments section, and they will not be repeated here.

[0125] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the system can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0126] Figure 8 This is a schematic diagram of the structure of a control device provided in one embodiment of this application. Figure 8 As shown, the control device 6 in this embodiment includes: at least one processor 60 ( Figure 8 Only one is shown in the image), at least one memory 61 ( Figure 8 (Only one is shown in the image) and a computer program 62 stored in the at least one memory 61 and executable on the at least one processor 60, wherein when the processor 60 executes the computer program 62, it causes the control device 6 to perform the steps in any of the above embodiments of the gas-assisted injection molding method for automotive door interior panels, or causes the control device 6 to perform the functions of each module / unit in the above embodiments of the system.

[0127] For example, the computer program 62 may be divided into one or more modules / units, which are stored in the memory 61 and executed by the processor 60 to complete this application. The one or more modules / units may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program 62 in the control device 6.

[0128] The control device 6 can be a desktop computer, laptop, or other computing device. This control device may include, but is not limited to, a processor 60 and a memory 61. Those skilled in the art will understand that... Figure 8 This is merely an example of control device 6 and does not constitute a limitation on control device 6. It may include more or fewer components than shown, or combine certain components, or different components, such as input / output devices, network access devices, buses, etc.

[0129] The processor 60 can be a Central Processing Unit (CPU), or it can be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor.

[0130] In some embodiments, the memory 61 may be an internal storage unit of the control device 6, such as a hard disk or memory of the control device 6. In other embodiments, the memory 61 may be an external storage device of the control device 6, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc., equipped on the control device 6. Furthermore, the memory 61 may include both internal storage units and external storage devices of the control device 6. The memory 61 is used to store operating systems, applications, bootloaders, data, and other programs, such as the program code of computer programs. The memory 61 can also be used to temporarily store data that has been output or will be output.

[0131] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps in any of the above method embodiments.

[0132] This application provides a computer program product that, when run on a gas-assisted injection molding machine for automotive door interior panels, enables the machine to perform the steps described in any of the above method embodiments.

[0133] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include at least: any entity or device capable of carrying the computer program code to a gas-assisted injection molding equipment for automotive door interior panels, a recording medium, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, such as a USB flash drive, a portable hard drive, a magnetic disk, or an optical disk.

[0134] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0135] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0136] In the embodiments provided in this application, it should be understood that the disclosed gas-assisted injection molding system, equipment, and method for automotive door interior panels can be implemented in other ways. For example, the embodiments of the automotive door interior panel gas-assisted injection molding system and equipment described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0137] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0138] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A gas-assisted injection molding method for automotive door inner panel, characterized in that, include: A three-dimensional model of the cavity of the automotive door inner panel mold is obtained, and a high shrinkage risk area is determined based on the three-dimensional model of the cavity; wherein, the transition rounded corner area between the transverse reinforcing rib and the panel body is marked in the three-dimensional model of the cavity; The target pressure holding area for gas-assisted injection is determined based on the high shrinkage risk region; wherein, the target pressure holding area is used to indicate the location where pressure needs to be held during gas-assisted injection; The main gas penetration channel is obtained based on the target pressure holding area; wherein, the main gas penetration channel is a medium-air channel formed inside the thick wall after the high-pressure gas pushes the unsolidified melt away from the center; Based on the main gas penetration channel, a simulation is performed to determine the isolated thick-walled region within the target pressure-holding area, and an auxiliary gas compensation path is determined according to the isolated thick-walled region; wherein, the endpoint of the auxiliary gas compensation path is located on one side of the main gas penetration channel; A comprehensive gas injection strategy is obtained based on the main gas penetration channel and the auxiliary gas compensation path, and the gas-assisted injection device is controlled to perform injection molding operation based on the comprehensive gas injection strategy. Among them, based on the simulation of the main gas penetration channel, the isolated thick-walled region within the target pressure-holding area is determined, including: Based on the main gas penetration channel, a gas pressure field simulation is performed within the target pressure holding region to obtain the steady-state gas pressure value within the target pressure holding region; Based on the steady-state gas pressure value, a low-pressure retention area is determined where the gas pressure is less than that of the main channel area and the wall thickness is greater than that of the average wall thickness of the protective plate body, and the low-pressure retention area is identified as the isolated thick-walled area. Determining the auxiliary gas compensation path based on the isolated thick-walled region includes: An analysis of the spatial location of the isolated thick-walled region and the relative orientation relationship with the main gas penetration channel yields an orientation result; wherein, the orientation result is used to indicate the positional relationship of the isolated thick-walled region relative to the main gas penetration channel; Based on the orientation results, the sidewall point of the geometric center of the isolated thick-walled region is determined on the main gas penetration channel, and the sidewall point is used as the starting connection point of the auxiliary gas compensation path; A straight line or curve is determined from the starting connection point toward the geometric center of the isolated thick-walled region, and the straight line or curve is determined as the auxiliary gas compensation path.

2. The gas-assisted injection molding method for automotive door inner panel as described in claim 1, characterized in that, The determination of the target pressure-holding area for gas-assisted injection based on the high-sinking-risk region includes: Determine the center point of the high shrinkage risk region, and use the center point as the center of the sphere and X times the length of the protective plate body wall thickness as the radius to obtain a spherical pressure-holding envelope surface; The area on the back of the transverse reinforcing rib covered by the spherical pressure-holding envelope and the adjacent protective plate body are defined as the target pressure-holding area.

3. The gas-assisted injection molding method for automotive door inner panel as described in claim 2, characterized in that, The process of obtaining the main gas penetration channel based on the target pressure-holding region includes: Within the target pressure holding area, the initial gas channel axis is determined with the gate center as the starting point and the final solidification point of the high shrinkage risk zone as the ending point, based on the starting point and the ending point. Based on the initial gas channel axis, the path is optimized within the target pressure holding area according to the optimization requirements to obtain the optimization result; wherein, the optimization requirements are that the optimized channel path should maintain a certain distance in space from the cooling water channel in the mold and the key edges of the product appearance, and the overall direction of the optimized channel path is parallel to the flow direction of the plastic melt from the gate to the final solidification point. The main gas penetration channel is determined based on the optimization results; wherein, the minimum distance between the main gas penetration channel and the decorative surface of the protective panel is not less than the thickness of the cured layer in the transition rounded corner area.

4. The gas-assisted injection molding method for automotive door inner panel as described in claim 1, characterized in that, The step of obtaining a comprehensive gas injection strategy based on the main gas penetration channel and the auxiliary gas compensation path, and controlling the gas-assisted injection device to perform injection molding operation based on the comprehensive gas injection strategy, includes: The main gas penetration channel and the auxiliary gas compensation path are spatially integrated to obtain a spatial integration result; wherein, the spatial integration result includes the relative positional relationship and intersection position between the main gas penetration channel and the auxiliary gas compensation path, and the intersection position refers to the point where the starting connection point intersects with the sidewall of the main gas penetration channel; Based on the spatial integration results, the timing sequence of gas injection is determined; Adjust the gas injection parameters; wherein the gas injection parameters include gas injection pressure and injection duration, and the gas injection pressure of the main gas penetration channel is set to be higher than the gas injection pressure of the auxiliary gas compensation path; Based on the time sequence and the gas injection parameters, a comprehensive gas injection strategy is generated, and based on the comprehensive gas injection strategy, the gas-assisted injection device is controlled to perform injection molding operation.

5. The gas-assisted injection molding method for automotive door inner panel as described in claim 4, characterized in that, The determination of the timing sequence of gas injection based on the spatial integration results includes: The flow path distance from the starting connection point to the gas injection gate along the main gas penetration channel is determined based on the intersection position and the relative position relationship; wherein, the flow path distance is the distance that the gas needs to travel in the main gas penetration channel; The delay time and flow time are calculated based on the flow channel distance; wherein, the delay time is used to indicate the time that the gas needs to wait before it can start flowing from the starting connection point, and the flow time is used to indicate the time required for the gas to flow from the starting connection point to the gas injection gate; The delay time and the flow time are sorted to obtain the time sequence of gas injection.

6. The gas-assisted injection molding method for automotive door inner panel as described in claim 1, characterized in that, The process of obtaining a three-dimensional model of the cavity of the automotive door inner panel mold and determining the high shrinkage risk region based on the three-dimensional model includes: Based on the position of the horizontal reinforcing rib, the thickness gradient of the transition rounded corner area is analyzed to obtain the thickness ratio of the maximum wall thickness to the average wall thickness of the adjacent area. When the thickness ratio is greater than the preset shrinkage threshold, the transition rounded corner area is defined as a high shrinkage risk area.

7. The gas-assisted injection molding method for automotive door inner panel as described in claim 6, characterized in that, The method further includes: When the thickness ratio is less than a preset shrinkage threshold, prompt data is generated; wherein, the prompt data is used to indicate that no auxiliary gas compensation path is required.

8. A gas-assisted injection molding apparatus for an automotive door interior panel, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method as described in any one of claims 1 to 7.

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