Injection blow hollow molding control method and system based on data monitoring

Abstract

The present application relates to the technical field of blow molding control, in particular to a kind of injection blow hollow forming control method and system based on data monitoring, embryo in the blow molding process will exist different state change dimension, through the change of embryo internal pressure in time sequence, bubble inflation rate, the change of the uniformity of the thickness distribution of ingredients, and the change of embryo volume, the blow molding process is divided into the pre-blowing stage of initial condition, expansion stage, shaping stage and cooling stage;Then based on the monitoring data of each stage, the starting time of each stage is adjusted, the problem that the frequent blow molding parameter adjustment based on the real-time production data monitored by sensor can cause the instability of melt rate expansion, resulting in uneven wall thickness, so that the injection blow hollow forming effect is better.

Description

Technical Field

[0001] This invention relates to the field of blow molding control technology, specifically to a data monitoring-based injection blow molding control method and system. Background Technology

[0002] Injection blow molding machines are devices used to manufacture hollow plastic products. They work by heating and melting plastic material, injecting it into a mold, and then expanding the plastic through blowing or other methods to form a product with a hollow structure. Considering that the preform undergoes various state changes during blow molding, setting fixed blow molding parameters usually cannot meet the molding requirements of the preform. Therefore, currently, during the blow molding process of samples using injection blow molding machines, real-time production data is generally monitored by sensors, and blow molding parameters are optimized and adjusted in real time to improve product quality.

[0003] However, in the actual blow molding process, the molten plastic needs to be evenly expanded to the inner wall of the mold under stable pressure. If the blow molding parameters are frequently adjusted based on real-time production data monitored by sensors, the expansion rate of the melt will be unstable, resulting in uneven wall thickness and poor blow molding effect. Summary of the Invention

[0004] This application provides a data-monitored injection blow molding control method and system. During the blow molding process, the preform undergoes different state changes. By analyzing the changes in internal pressure, bubble expansion rate, uniformity of thickness distribution, and volume of the preform over time, the blow molding process is divided into a pre-blowing stage, an expansion stage, a shaping stage, and a cooling stage. Then, based on the monitoring data of each stage, the blow molding parameters are adjusted at the beginning of each stage. This solves the problem of unstable melt rate expansion and uneven wall thickness caused by frequent adjustments to blow molding parameters based on real-time production data monitored by sensors, resulting in better injection blow molding performance.

[0005] The first aspect of this application provides a data monitoring-based injection blow molding control method, the method comprising:

[0006] During the blow molding process, the bubble expansion rate, internal pressure of the preform, volume of the preform, mold temperature, and wall thickness of the preform at each sampling point are obtained at each sampling time.

[0007] Based on the abrupt change in the rate of change of internal pressure of the billet over time and the instantaneous increase in the rate of bubble expansion at each sampling moment, the first division coefficient for each sampling moment is determined; based on the temporal increase of the first division coefficient at each sampling moment over time, the start time of the expansion stage is determined; based on the standard deviation of the billet volume at the start time of the expansion stage, the control parameters for the expansion stage are determined.

[0008] The start time of the shaping stage is determined based on the temporal decrease of the first division coefficient at each sampling time after the start time of the expansion stage; the control parameters of the shaping stage are determined based on the standard deviation of the blank wall thickness at all monitoring points at the start time of the shaping stage.

[0009] Based on the uniformity of the blank wall thickness distribution and the standard deviation of the blank volume at each monitoring point after the start of the shaping stage, the second division coefficient at each sampling point is determined; the start time of the cooling stage is determined based on the second division coefficient; and the cooling stage control parameters are determined based on the overall size of the blank wall thickness at all monitoring points and the corresponding mold temperature at the start time of the cooling stage.

[0010] The blow molding parameters are adjusted according to the expansion stage control parameters, the shaping stage control parameters, and the cooling stage control parameters.

[0011] Furthermore, the process of obtaining the first partitioning coefficient includes:

[0012] Based on the average internal pressure of the billet at all sampling times prior to each sampling time, the historical reference pressure at each sampling time is determined; based on the difference between the internal pressure of the billet at each sampling time and the historical reference pressure, the historical pressure change value at each sampling time is determined; the difference between the internal pressure of the billet at each sampling time and the internal pressure of the billet at the next sampling time is used as the reference pressure change value at each sampling time; based on the difference between the reference pressure change value and the historical pressure change value, the degree of internal pressure change at each sampling time is determined.

[0013] The difference between the bubble expansion rate at each sampling time and the bubble expansion rate at the previous sampling time is used to determine the expansion rate increase value at each sampling time.

[0014] The product between the degree of internal pressure change and the expansion rate increase is normalized to determine the first division coefficient at each sampling time.

[0015] Furthermore, the process of obtaining the start time of the expansion phase includes:

[0016] In terms of time sequence, the next sampling moment after the sampling moment when the first dividing coefficient is greater than the preset expansion threshold is taken as the start moment of the expansion phase.

[0017] Furthermore, the process of obtaining the expansion stage control parameters includes:

[0018] The positive correlation mapping value between the blank volume at the beginning of the expansion stage and the standard mold capacity is used as the expansion stage control weight at the beginning of the expansion stage.

[0019] The expansion stage blowing pressure is determined by the product of the expansion stage control weight and the preset initial blowing pressure; the expansion stage mold temperature is determined by the product of the expansion stage control weight and the preset initial mold temperature.

[0020] The blowing pressure and the mold temperature during the expansion stage are used as the control parameters for the expansion stage.

[0021] Furthermore, the process of obtaining the start time of the finalization stage includes:

[0022] After the start of the expansion phase, the next sampling time after the sampling time when the first division coefficient is less than the preset shaping threshold for the first time in the time sequence is taken as the start time of the shaping phase.

[0023] Furthermore, the process of obtaining the control parameters during the finalization stage includes:

[0024] The minimum wall thickness of the preform at all monitoring points at the start of the shaping stage is positively correlated with the difference between the preset plastic sample thickness, and the shaping stage control weight at the start of the shaping stage is determined.

[0025] The blowing pressure in the shaping stage is determined by the product of the control weight in the shaping stage and the blowing pressure in the expansion stage; the mold temperature in the shaping stage is determined by the product of the negative correlation mapping value of the control weight in the shaping stage and the mold temperature in the expansion stage.

[0026] The blowing pressure and mold temperature during the shaping stage are used as the control parameters for the shaping stage.

[0027] Furthermore, the process of obtaining the second dividing coefficient includes:

[0028] After the start of the shaping stage, the difference between the blank volume and the standard capacity of the mold at each sampling time is used as the volume standard deviation value at each sampling time.

[0029] The product of the variance of the blank wall thickness at all monitoring points at each sampling time and the volume standard deviation is normalized to determine the second division coefficient at each sampling time.

[0030] Furthermore, the process of obtaining the start time of the cooling phase includes:

[0031] After the start of the finalization stage, the sampling time when the second division coefficient is less than the preset cooling threshold for the first time in the time sequence is taken as the start time of the cooling stage.

[0032] Furthermore, the process of obtaining the cooling stage control parameters includes:

[0033] The average thickness of the blank wall at all monitoring points at the start of the cooling stage is taken as the degree of thermal conductivity influence of the thickness; the difference between the mold temperature and the prior cooling water temperature at the start of the cooling stage is taken as the thermal conductivity reference temperature difference; the normalized value of the product between the degree of thermal conductivity influence of the thickness and the thermal conductivity reference temperature difference is positively correlated to determine the cooling stage control weight at the start of the cooling stage.

[0034] The cooling time of the cooling stage is determined by multiplying the cooling stage control weight by the preset prior cooling duration; the cooling time of the cooling stage is used as the cooling stage control parameter.

[0035] Secondly, this application provides a data monitoring-based injection blow molding control system, the system comprising:

[0036] The data acquisition module is used to acquire the bubble expansion rate, internal pressure of the preform, volume of the preform, mold temperature, and wall thickness of the preform at each sampling point during the blow molding process.

[0037] The expansion stage control parameter determination module is used to determine the first division coefficient for each sampling moment based on the abrupt change in the rate of change of the internal pressure of the billet in the time sequence and the instantaneous increase in the bubble expansion rate at each sampling moment; to determine the start time of the expansion stage based on the temporal increase of the first division coefficient at each sampling moment in the time sequence; and to determine the expansion stage control parameters based on the standard deviation of the billet volume at the start time of the expansion stage.

[0038] The module for determining the control parameters of the shaping stage is used to determine the start time of the shaping stage based on the temporal decrease of the first division coefficient at each sampling time after the start time of the expansion stage; and to determine the control parameters of the shaping stage based on the standard deviation of the billet wall thickness at all monitoring points at the start time of the shaping stage.

[0039] The cooling stage control parameter determination module is used to determine the second division coefficient at each sampling time based on the uniformity of the blank wall thickness distribution and the standard deviation of the blank volume at each monitoring point after the start of the shaping stage; determine the start time of the cooling stage based on the second division coefficient; and determine the cooling stage control parameters based on the overall size of the blank wall thickness at all monitoring points and the corresponding mold temperature at the start time of the cooling stage.

[0040] The blow molding parameter adjustment module is used to adjust the blow molding parameters according to the expansion stage control parameters, the shaping stage control parameters, and the cooling stage control parameters.

[0041] Thirdly, this application provides a computer device including a memory and a processor. The memory is used to store computer program code, and the processor is used to call and run the computer program code from the memory to perform the method as described in the first aspect of this application or any embodiment of the first aspect.

[0042] Fourthly, this application provides a computer program product comprising computer program code, which, when executed, performs the method as described in the first aspect of this application or any embodiment thereof.

[0043] Fifthly, this application provides a computer-readable storage medium that stores computer program code, which, when executed, performs the method as described in the first aspect of this application or any embodiment thereof.

[0044] This application has the following beneficial effects:

[0045] In the initial stage, i.e., the pre-blowing stage, the plastic has just softened and entered the mold. The molten plastic is preheated within the mold and forms initial bubbles through a small amount of gas. In the expansion stage, the bubbles rapidly expand, approaching the complex shape of the mold, requiring a gradual increase in pressure and temperature. Therefore, the expansion stage exhibits a faster bubble expansion rate and a relatively faster change in internal pressure of the preform compared to the pre-blowing stage. Based on this characteristic, this application determines a first dividing coefficient according to the abrupt changes in the rate of change of internal pressure of the preform over time and the instantaneous increase in the bubble expansion rate at each sampling moment, and determines the start time of the expansion stage based on this first dividing coefficient. For the expansion stage, it is necessary to ensure that the preform fully fills all parts of the mold. Therefore, it is necessary to increase the blowing pressure in this stage while maintaining a synchronous increase in mold temperature and blowing pressure to facilitate easier expansion of the preform. Since this stage primarily aims at expansion, the blowing pressure must be set to a level that allows the volume of the preform to reach the capacity of the mold. Therefore, the expansion rate can be determined by using the difference between the preform volume and the mold capacity, thereby determining the control parameters for the expansion stage.

[0046] During the setting stage, the plastic is in complete contact with the mold, requiring continued pressure increase to ensure the mold fills all details at a rapid rate. Compared to the expansion stage, the preform in the setting stage is completely adhered to the mold. At this point, the changes in internal pressure and bubble expansion rate are usually relatively stable, and the corresponding first dividing coefficient is typically small. Therefore, the start time of the setting stage can be determined based on the temporal decrease of the first dividing coefficient. In the setting stage, the preform shape is close to the mold surface, and this stage requires ensuring the preform fills all details of the mold to improve wall thickness uniformity. Therefore, the blowing pressure needs to be increased further, while the mold temperature needs to be appropriately reduced to allow the preform to cool and solidify, maintaining its adherence to the mold wall. Since the goal of this stage is to improve wall thickness uniformity, the setting stage control parameters can be determined based on the standard deviation of the preform wall thickness at each monitoring point at the start of the setting stage.

[0047] The cooling stage requires appropriate temperature control to cool and solidify the plastic while maintaining the product shape. Since the volume of the preform during the cooling and setting stages is almost equal to the mold size, the internal pressure and bubble expansion of the preform remain stable. Therefore, the start time of the cooling stage cannot be determined based on the first dividing factor. Furthermore, the preform needs to maintain a uniform wall thickness during the setting stage to ensure a high-quality finished product during cooling. The volume of the preform corresponding to a high-quality finished product should be very close to the mold capacity. Therefore, considering this characteristic, a second dividing factor is determined for each sampling time based on the uniformity of the preform wall thickness distribution and the standard deviation of the preform volume at each monitoring point after the start time of the setting stage. This second dividing factor allows for a more accurate determination of the start time of the cooling stage. For the cooling stage, blowing pressure and mold temperature are usually not required; instead, the sample is solidified by the circulation of cooling water. Therefore, this step requires determining an expected cooling time to improve production efficiency. Since thicker product walls reduce thermal conductivity, resulting in longer cooling times, and higher mold temperatures at the start of the cooling phase also require longer cooling times, the final cooling phase control parameters are determined based on the overall wall thickness of the blank at all monitoring points and the corresponding mold temperatures at the start of the cooling phase.

[0048] Finally, the blow molding parameters are adjusted according to the control parameters determined at each stage of the blow molding process, making the adjustment of blow molding parameters during the blow molding process more reasonable. This solves the problem that frequent adjustments of blow molding parameters based on real-time production data monitored by sensors can lead to unstable melt rate expansion and uneven wall thickness, resulting in better injection blow hollow molding effect. Attached Figure Description

[0049] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 A flowchart illustrating a data monitoring-based injection blow molding control method according to an embodiment of the present invention;

[0051] Figure 2 This is a structural diagram of a data monitoring-based injection blow molding control system provided in one embodiment of the present invention.

[0052] Figure 3 This is a schematic diagram of a computer device structure provided in one embodiment of the present invention. Detailed Implementation

[0053] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a data monitoring-based injection blow molding control method and system proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment, and specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0055] The following description, in conjunction with the accompanying drawings, details a specific scheme for a data-monitored injection blow molding control method and system provided by the present invention.

[0056] This application provides a data monitoring-based injection blow molding control method. Please refer to [link to relevant documentation]. Figure 1 The diagram illustrates a flowchart of a data monitoring-based injection blow molding control method according to an embodiment of the present invention. The method includes:

[0057] Step S101: During the blow molding process, obtain the bubble expansion rate, internal pressure of the preform, volume of the preform, mold temperature, and wall thickness of the preform at each sampling point.

[0058] In one specific implementation of this invention, the time interval between two adjacent sampling times is set to 0.1s, which can be adjusted according to the specific implementation environment.

[0059] Temperature, pressure, and ultrasonic sensors are integrated at the end of the blown mandrel. The temperature sensor collects the mold temperature at each sampling moment, and the pressure sensor collects the internal pressure of the blank at each sampling moment. The ultrasonic sensor collects the bubble expansion rate at each sampling moment. The process of obtaining the bubble expansion rate includes: measuring the average of all distance data at each sampling moment using the ultrasonic sensor, calculating the difference between the average of all distance data at each sampling moment and the average of all distance data at the previous sampling moment, and using the normalized value of the ratio of this difference to the time interval between the corresponding two sampling moments as the bubble expansion rate. The implementer can also measure the bubble expansion rate using other methods depending on the specific implementation environment, such as directly using the normalized value of the average of all distance data at each sampling moment as the bubble expansion rate, which will not be elaborated further here. Furthermore, an ultrasonic thickness gauge is set at each monitoring point in the mold cavity to determine the blank wall thickness at each monitoring point. The monitoring points can be evenly distributed in the mold cavity or randomly set, depending on the specific implementation environment. In one specific implementation of this invention, the inner cavity of the mold is divided into a uniform grid, with the length and width of the grid both set to 0.5 cm. The center point of each grid is used as the corresponding monitoring point, and the grid size can be adjusted according to the specific implementation environment.

[0060] Step S102: Based on the abrupt change in the rate of change of internal pressure of the billet in the time sequence and the instantaneous increase in the bubble expansion rate at each sampling moment, determine the first division coefficient for each sampling moment; based on the temporal increase of the first division coefficient at each sampling moment in the time sequence, determine the start time of the expansion stage; based on the standard deviation of the billet volume at the start time of the expansion stage, determine the control parameters for the expansion stage.

[0061] In the initial stage, i.e., the pre-blowing stage, the plastic has just softened and entered the mold. The molten plastic is preheated within the mold and forms initial bubbles through a small amount of gas. In the expansion stage, the bubbles rapidly expand, approaching the complex shape of the mold, requiring a gradual increase in pressure and temperature. Therefore, the expansion stage exhibits a faster bubble expansion rate and a relatively faster change in internal pressure of the preform compared to the pre-blowing stage. Based on this characteristic, this application determines a first dividing coefficient according to the abrupt changes in the rate of change of internal pressure of the preform over time and the instantaneous increase in the bubble expansion rate at each sampling moment, and determines the start time of the expansion stage based on this first dividing coefficient. For the expansion stage, it is necessary to ensure that the preform fully fills all parts of the mold. Therefore, it is necessary to increase the blowing pressure in this stage while maintaining a synchronous increase in mold temperature and blowing pressure to facilitate easier expansion of the preform. Since this stage primarily aims at expansion, the blowing pressure must be set to a level that allows the volume of the preform to reach the capacity of the mold. Therefore, the expansion rate can be determined by using the difference between the preform volume and the mold capacity, thereby determining the control parameters for the expansion stage.

[0062] Preferably, in some possible implementations of the embodiments of the present invention, the process of obtaining the first dividing coefficient includes:

[0063] Based on the average internal pressure of the billet at all sampling times prior to each sampling time, the historical reference pressure for each sampling time is determined. The historical pressure change value for each sampling time is determined based on the difference between the internal pressure of the billet at each sampling time and the historical reference pressure. The difference between the internal pressure of the billet at each sampling time and the internal pressure of the billet at the next sampling time is used as the reference pressure change value for each sampling time. The degree of internal pressure abrupt change at each sampling time is determined based on the difference between the reference pressure change value and the historical pressure change value. The historical pressure change value characterizes the overall change in the internal pressure of the billet at the current time compared to the internal pressure of the billet at all previous sampling times. The reference pressure change value represents the change in the internal pressure of the billet between each sampling time and the next sampling time. The smaller the difference between the corresponding historical pressure change value and the reference pressure change value, i.e., the smaller the degree of internal pressure abrupt change, the more balanced the pressure change before and after the corresponding sampling time, the more stable the internal pressure change of the billet, and the lower the probability of entering the expansion stage. Conversely, the greater the degree of internal pressure abrupt change, the more unstable the internal pressure change of the billet, and the greater the probability of entering the expansion stage.

[0064] The difference between the bubble expansion rate at each sampling time and the bubble expansion rate at the previous sampling time is used to determine the expansion rate increase value at each sampling time. The larger the increase value, the faster the bubble expansion rate increases, the more unstable the bubble expansion rate, and the greater the probability of entering the expansion stage; conversely, the smaller the increase value, the more stable the bubble expansion rate, and the lower the probability of entering the expansion stage.

[0065] Furthermore, based on the characteristic that the greater the degree of internal pressure change and the greater the increase in expansion rate, the greater the probability of entering the expansion phase, the product between the degree of internal pressure change and the increase in expansion rate is normalized to determine the first dividing coefficient at each sampling time. This ensures that the larger the first dividing coefficient, the greater the probability of entering the expansion phase at the corresponding sampling time. In a specific implementation of this invention, the process of obtaining the first dividing coefficient is expressed by the formula: ;in, For the first The first division coefficient at each sampling time; For the first Internal pressure of the billet at each sampling time; For the first The average internal pressure of the billet at all sampling times prior to the nth sampling time, i.e., the nth sampling time. Historical reference pressure at each sampling time; It is the absolute value symbol; For the first Historical pressure change values ​​at each sampling time; For the first The internal pressure of the blank at the sampling time, that is, the first sampling time. The internal pressure of the billet at the next sampling time after the previous sampling time; For the first Reference pressure change values ​​at each sampling time; For the first The degree of internal pressure change at each sampling time; For the first Bubble expansion rate at each sampling time; For the first The bubble expansion rate at the sampling time, i.e. the th sampling time. Bubble expansion rate at the previous sampling time; This is a linear normalization function, and implementers can adjust the normalization method according to the specific implementation environment. It should be noted that, in addition to the normalized value of the product, implementers can also calculate the first division coefficient through other methods based on the correlation, such as the normalized value of the sum between the degree of internal pressure change and the expansion rate growth, etc., which will not be elaborated further here.

[0066] Preferably, in some possible implementations of the embodiments of the present invention, the process of obtaining the start time of the expansion phase includes:

[0067] Since a larger first dividing coefficient indicates a higher probability of being in the expansion phase, meaning the first dividing coefficient is usually larger at the start of the expansion phase, the next sampling time after the first sampling time where the first dividing coefficient is greater than the preset expansion threshold is taken as the start time of the expansion phase in chronological order. In a specific implementation of this invention, the preset expansion threshold is set to 0.85, which can be adjusted according to the specific implementation environment. The reason for setting the next sampling time after the first sampling time where the first dividing coefficient is greater than the preset expansion threshold as the start time of the expansion phase is that the calculation of the first dividing coefficient is combined with the next sampling time of each sampling time, so setting the next sampling time as the start time of the expansion phase is more reasonable and allows for real-time adjustment.

[0068] Preferably, in some possible implementations of the embodiments of the present invention, the process of obtaining the expansion stage control parameters includes:

[0069] The positive correlation mapping between the blank volume at the start of the expansion stage and the standard mold capacity is used as the control weight for the expansion stage at the start of the expansion stage. When entering the expansion stage, given that the main purpose of the expansion stage is expansion, the blowing pressure must be set to ensure that the blank volume reaches the mold capacity. Therefore, the smaller the blank volume at the start of the expansion stage, the greater the required blowing pressure. Furthermore, since increasing the blowing pressure requires a simultaneous increase in mold temperature to more easily expand the blank, a smaller blank volume requires not only a greater blowing pressure but also a higher mold temperature. Therefore, after normalizing the blank volume using the standard mold capacity, a positive correlation mapping is used to obtain a value that conforms to the control weight, thus determining the control weights of blowing pressure and mold temperature during the expansion stage. It should be noted that the standard mold capacity refers to the size of the mold, which is prior data and will not be further elaborated upon here.

[0070] Further, the expansion stage blowing pressure is determined by multiplying the expansion stage control weight by the preset initial blowing pressure; the expansion stage mold temperature is determined by multiplying the expansion stage control weight by the preset initial mold temperature; the expansion stage blowing pressure and expansion stage mold temperature are used as expansion stage control parameters. That is, the preset initial blowing pressure and preset initial mold temperature are controlled by the obtained expansion stage control weight, thereby determining the expansion stage control parameters. The preset initial blowing pressure is the blowing pressure in the pre-blowing stage, and the preset initial mold temperature is the mold temperature in the pre-blowing stage. In the pre-blowing stage, due to the unstable melting rate, a smaller blowing pressure and a lower mold temperature are required for pre-blowing to form the blank, thereby allowing the plastic melt to spread evenly and begin to diffuse towards the mold wall; that is, the preset initial blowing pressure and preset initial mold temperature need to be set relatively low. In a specific implementation of this invention, the preset initial mold temperature is set to 60 degrees Celsius, and the preset initial blowing pressure is set to 0.5 MPa. The magnitude of the preset initial mold temperature and preset initial blowing pressure can be adjusted according to the specific implementation environment.

[0071] In one specific implementation of this invention, the process of obtaining the blowing pressure during the expansion stage is expressed by the following formula: ;in This refers to the blowing pressure during the expansion phase. Preset initial blowing pressure; The start of the expansion phase The volume of the blank below; Standard capacity for molds; It is a logarithmic function with the natural constant as its base; The start of the expansion phase The expansion phase adjustment weight; it should be noted that when When the value is less than 0.01, replace it with 0.01. The blowing pressure during the expansion stage is calculated to prevent excessive adjustment weights that might not be suitable for the implementation environment. Other values ​​can be used to replace 0.01 depending on the specific implementation environment; this will not be elaborated further here. The process of obtaining the mold temperature during the expansion stage is expressed by the formula: ;in, This refers to the mold temperature during the expansion stage. This is to preset the initial mold temperature.

[0072] Step S103: Determine the start time of the shaping stage based on the temporal decrease of the first division coefficient at each sampling time after the start time of the expansion stage; determine the shaping stage control parameters based on the standard deviation of the blank wall thickness at all monitoring points at the start time of the shaping stage.

[0073] During the setting stage, the plastic is in complete contact with the mold, requiring continued pressure increase to ensure the mold fills all details at a rapid rate. Compared to the expansion stage, the preform in the setting stage is completely adhered to the mold. At this point, the changes in internal pressure and bubble expansion rate are usually relatively stable, and the corresponding first dividing coefficient is typically small. Therefore, the start time of the setting stage can be determined based on the temporal decrease of the first dividing coefficient. In the setting stage, the preform shape is close to the mold surface, and this stage requires ensuring the preform fills all details of the mold to improve wall thickness uniformity. Therefore, the blowing pressure needs to be increased further, while the mold temperature needs to be appropriately reduced to allow the preform to cool and solidify, maintaining its adherence to the mold wall. Since the goal of this stage is to improve wall thickness uniformity, the setting stage control parameters can be determined based on the standard deviation of the preform wall thickness at each monitoring point at the start of the setting stage.

[0074] Preferably, in some possible implementations of the embodiments of the present invention, the process of obtaining the start time of the finalization stage includes:

[0075] The expansion stage primarily aims at expansion, during which the blank continuously expands and enters the shaping stage upon fitting into the mold. Therefore, compared to the expansion stage, the internal pressure changes and bubble expansion rate changes are relatively more stable in the shaping stage. Consequently, the first dividing coefficient corresponding to the initial moment of the shaping stage is usually smaller. Therefore, after the start of the expansion stage, the next sampling moment in chronological order where the first dividing coefficient is less than a preset shaping threshold is taken as the start moment of the shaping stage. In a specific implementation of this invention, the preset shaping threshold is set to 0.3, which can be adjusted according to the specific implementation environment.

[0076] Preferably, in some possible implementations of the embodiments of the present invention, the process of obtaining the control parameters during the finalization stage includes:

[0077] The minimum wall thickness of the preform at all monitoring points at the start of the shaping stage is positively correlated with the difference between the preform wall thickness and the preset plastic sample thickness to determine the shaping stage control weight at the start of the shaping stage. In the shaping stage, the preform shape is close to the mold surface. This stage requires ensuring the preform fills all details of the mold and improves wall thickness uniformity. Therefore, the control weights for mold temperature and blowing pressure need to be analyzed in conjunction with wall thickness uniformity. At the start of the shaping stage, the smaller the minimum wall thickness of the preform at all monitoring points relative to the preset plastic sample thickness, the lower the preform's filling progress in the mold details, and the lower the wall thickness uniformity. Therefore, a higher blowing pressure is needed to improve wall thickness uniformity. Simultaneously, the mold temperature needs to be adjusted downwards according to the degree of blowing pressure adjustment to maintain shape stability. Therefore, the smaller the minimum wall thickness of the preform relative to the preset plastic sample thickness, i.e., the greater the difference between the minimum wall thickness of the preform and the preset plastic sample thickness, i.e., the greater the shaping stage control weight, the higher the blowing pressure and the lower the mold temperature in the shaping stage. Therefore, the blowing pressure in the shaping stage is further determined by the product of the control weight in the shaping stage and the blowing pressure in the expansion stage; the mold temperature in the shaping stage is determined by the product of the negative correlation mapping value of the control weight in the shaping stage and the mold temperature in the expansion stage. It should be noted that the preset plastic sample thickness needs to be determined based on the standard thickness of the sample to be molded. In one specific implementation of this invention, the preset plastic sample thickness is set to 4 mm. The specific value needs to be adjusted according to the specific implementation environment, and will not be elaborated further here.

[0078] Finally, based on the obtained blowing pressure and mold temperature during the shaping stage, these parameters are used as control parameters for the shaping stage. In a specific implementation of this invention, the process of obtaining the blowing pressure during the shaping stage is expressed by the following formula: ;in, This refers to the blowing pressure during the shaping stage; This refers to the blowing pressure during the expansion phase. Preset the thickness of the plastic sample; The start of the finalization phase The minimum value of the blank wall thickness at all monitoring points below; The absolute value symbol is used here to prevent the occurrence of absolute values. Greater than The situation is one that cannot be analyzed, so we use difference rather than difference value for analysis; It is a logarithmic function with the natural constant as its base; Adjusting weights during the finalization stage; To preset the positive correlation adjustment parameter, this embodiment of the invention sets it to 1.1. It can be adjusted according to the specific implementation environment, but the value usually needs to be greater than or equal to 1. ;in, This refers to the mold temperature during the shaping stage; This refers to the mold temperature during the expansion stage.

[0079] Step S104: Based on the uniformity of the blank wall thickness distribution and the standard deviation of the blank volume at each monitoring point after the start of the shaping stage, determine the second division coefficient at each sampling point; determine the start time of the cooling stage based on the second division coefficient; determine the cooling stage control parameters based on the overall size of the blank wall thickness at all monitoring points and the corresponding mold temperature at the start time of the cooling stage.

[0080] The cooling stage requires appropriate temperature control to cool and solidify the plastic while maintaining the product shape. Since the volume of the preform during the cooling and setting stages is almost equal to the mold size, the internal pressure and bubble expansion of the preform remain stable. Therefore, the start time of the cooling stage cannot be determined based on the first dividing factor. Furthermore, the preform needs to maintain a uniform wall thickness during the setting stage to ensure a high-quality finished product during cooling. The volume of the preform corresponding to a high-quality finished product should be very close to the mold capacity. Therefore, considering this characteristic, a second dividing factor is determined for each sampling time based on the uniformity of the preform wall thickness distribution and the standard deviation of the preform volume at each monitoring point after the start time of the setting stage. This second dividing factor allows for a more accurate determination of the start time of the cooling stage. For the cooling stage, blowing pressure and mold temperature are usually not required; instead, the sample is solidified by the circulation of cooling water. Therefore, this step requires determining an expected cooling time to improve production efficiency. Since thicker product walls reduce thermal conductivity, resulting in longer cooling times, and higher mold temperatures at the start of the cooling phase also require longer cooling times, the final cooling phase control parameters are determined based on the overall wall thickness of the blank at all monitoring points and the corresponding mold temperatures at the start of the cooling phase.

[0081] Preferably, in some possible implementations of the embodiments of the present invention, the process of obtaining the second division coefficient includes:

[0082] After the start of the shaping stage, the difference between the blank volume and the standard mold capacity at each sampling time is used as the volume standard deviation value for each sampling time. The product of the variance of the blank wall thickness at all monitoring points at each sampling time and the volume standard deviation is normalized to determine the second division coefficient for each sampling time. The wall thickness uniformity is higher and the blank volume is closer to the standard mold capacity during the cooling stage. Therefore, based on the characteristics of variance, the larger the variance of the blank wall thickness at all monitoring points at each sampling time and the larger the volume standard deviation value, the more likely the corresponding sampling time has not entered the cooling stage. Therefore, the smaller the second division coefficient, the greater the probability that the corresponding sampling time is in the cooling stage. In a specific implementation of this invention, the process of obtaining the second division coefficient is expressed by the formula: ;in, The first time after the start of the finalization stage The second division coefficient at each sampling time; The first time after the start of the finalization stage The variance of the blank wall thickness at all monitoring points at each sampling time; The first time after the start of the finalization stage The volume of the blank at each sampling time; Standard capacity for molds; The first time after the start of the finalization stage The standard deviation of volume at each sampling time; It is the absolute value symbol; This is a linear normalization function; other normalization methods can be used depending on the specific implementation environment.

[0083] Preferably, in some possible implementations of the embodiments of the present invention, the process of obtaining the start time of the cooling phase includes:

[0084] Since a smaller second dividing coefficient indicates a higher probability that the corresponding sampling time falls within the cooling phase, after the start of the finalization phase, the sampling time at which the second dividing coefficient first appears in chronological order and is less than the preset cooling threshold is taken as the start time of the cooling phase. In a specific implementation of this invention, the preset cooling threshold is set to 0.2, which can be adjusted according to the specific implementation environment.

[0085] Preferably, in some possible implementations of the embodiments of the present invention, the process of obtaining the cooling stage control parameters includes:

[0086] The average thickness of the blank wall at all monitoring points at the start of the cooling stage is used as the degree of thermal conductivity influence. The difference between the mold temperature and the prior cooling water temperature at the start of the cooling stage is used as the thermal conductivity reference temperature difference. A positive correlation mapping is performed on the normalized value of the product of the degree of thermal conductivity influence and the thermal conductivity reference temperature difference to determine the cooling stage control weight at the start of the cooling stage. The purpose of the cooling stage is to cool and solidify the plastic while maintaining the product shape. The cooling rate is related to the heat conduction rate; the faster the heat conduction rate, the longer the cooling time should be. Conversely, a larger blank wall thickness, i.e., a greater degree of thermal conductivity influence, makes heat conduction more difficult, resulting in a slower conduction rate and a longer cooling time requirement. Furthermore, a higher mold temperature at the start of the cooling stage, i.e., a larger thermal conductivity reference temperature difference, requires more heat to be conducted, necessitating a longer cooling time. Therefore, the larger the cooling stage control weight obtained by positively correlating the normalized value of the product of the degree of thermal conductivity influence and the thermal conductivity reference temperature difference, the longer the cooling time should be. The cooling time of the cooling stage is determined by multiplying the cooling stage control weight by the preset prior cooling duration; the cooling time of the cooling stage is used as the cooling stage control parameter. In one specific implementation of this invention, the preset prior cooling duration is set to 2 minutes, which needs to be adjusted according to the specific implementation environment.

[0087] In one specific implementation of this invention, the process of obtaining the cooling time during the cooling phase is expressed by the following formula: ;in, This refers to the cooling time during the cooling phase. Preset a priori cooling time; The start time of the cooling phase The mold temperature below; The prior cooling water temperature is a value obtained a priori and needs to be determined based on the temperature of the cooling water in the specific implementation environment. In a specific implementation of this invention, it is set to 10 degrees Celsius. It is the absolute value symbol; The start time of the cooling phase The thermal reference temperature difference below; The start time of the cooling phase The average thickness of the blank wall at all monitoring points is the corresponding thickness and its thermal conductivity effect. It is a linear normalization function, and implementers can adjust the normalization method according to the specific implementation environment; The start time of the cooling phase The cooling phase adjustment weight.

[0088] Step S105: Adjust the blow molding parameters according to the expansion stage control parameters, the shaping stage control parameters, and the cooling stage control parameters.

[0089] Finally, the blow molding parameters are adjusted based on the control parameters determined at each stage of the blow molding process. This makes the adjustment of blow molding parameters more reasonable, solving the problem of unstable melt rate expansion and uneven wall thickness caused by frequent adjustments based on real-time production data monitored by sensors. This results in better injection blow molding of hollow components. At the beginning of the expansion stage, the corresponding control parameters are adjusted according to the expansion stage control parameters. Specifically, the blowing pressure and mold temperature in the expansion stage are adjusted to match the expansion stage mold temperature. Similarly, at the beginning of the setting stage, the corresponding control parameters are adjusted according to the setting stage control parameters. Specifically, the blowing pressure and mold temperature in the setting stage are adjusted to match the setting stage mold temperature. At the beginning of the cooling stage, the corresponding control parameters are adjusted according to the cooling stage control parameters. Specifically, the cooling time in the cooling stage is adjusted to match the cooling time in the cooling stage.

[0090] In summary, a data-monitored injection blow molding control method addresses the different state changes of the preform during blow molding. By analyzing the temporal changes in internal pressure, bubble expansion rate, uniformity of thickness distribution, and preform volume, the blow molding process is divided into four stages: pre-blowing, expansion, shaping, and cooling. Then, based on monitoring data from each stage, the blow molding parameters are adjusted at the start of each stage. This solves the problem of frequent adjustments to blow molding parameters based on real-time production data from sensors, which can lead to unstable melt rate expansion and uneven wall thickness. This method results in better injection blow molding performance.

[0091] This application also provides a data monitoring-based injection blow molding control system; please refer to [link to relevant documentation]. Figure 2 The diagram shows a structural diagram of a data monitoring-based injection blow molding control system according to an embodiment of the present invention. The system includes: a data acquisition module 201, an expansion stage control parameter determination module 202, a shaping stage control parameter determination module 203, a cooling stage control parameter determination module 204, and a blow molding parameter adjustment module 205.

[0092] The data acquisition module 201 is used to acquire the bubble expansion rate, internal pressure of the preform, volume of the preform, mold temperature and wall thickness of the preform at each sampling moment during the blow molding process.

[0093] The expansion stage control parameter determination module 202 is used to determine the first division coefficient for each sampling moment based on the abrupt change in the rate of change of the internal pressure of the billet in the time sequence and the instantaneous increase in the bubble expansion rate at each sampling moment; to determine the start time of the expansion stage based on the temporal increase of the first division coefficient at each sampling moment in the time sequence; and to determine the expansion stage control parameters based on the standard deviation of the billet volume at the start time of the expansion stage.

[0094] The shaping stage control parameter determination module 203 is used to determine the start time of the shaping stage based on the temporal decrease of the first division coefficient at each sampling time after the start time of the expansion stage; and to determine the shaping stage control parameters based on the standard deviation of the billet wall thickness at all monitoring points at the start time of the shaping stage.

[0095] The cooling stage control parameter determination module 204 is used to determine the second division coefficient at each sampling time based on the uniformity of the blank wall thickness distribution and the standard deviation of the blank volume at each monitoring point position after the start of the shaping stage; determine the start time of the cooling stage based on the second division coefficient; and determine the cooling stage control parameters based on the overall size of the blank wall thickness at all monitoring point positions and the corresponding mold temperature at the start time of the cooling stage.

[0096] The blow molding parameter adjustment module 205 is used to adjust the blow molding parameters according to the control parameters of the expansion stage, the control parameters of the shaping stage, and the control parameters of the cooling stage.

[0097] It should be noted that the system provided in the above embodiments is only an example of the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the computer device can be divided into different functional modules to complete all or part of the functions described above. In addition, the injection blow molding control system based on data monitoring and the injection blow molding control method based on data monitoring provided in the above embodiments belong to the same concept. The specific implementation process is detailed in the method embodiment and will not be repeated here.

[0098] This application also provides a computer device; please refer to [link / reference]. Figure 3 The illustration shows a schematic diagram of a computer device structure provided by an embodiment of the present invention. The computer device includes a memory 301, a processor 302, and a computer program 303 stored in the memory 301 and running on the processor 302. When the processor 302 executes the computer program 303, the computer device can execute any of the aforementioned data monitoring-based injection blow molding control methods.

[0099] This application also provides a computer program product that, when run on a computer device, enables the computer device to execute any of the aforementioned data monitoring-based injection blow molding control methods.

[0100] This application also provides a computer-readable storage medium storing computer program code. When the computer program code is run on a computer device, the computer device can execute any of the aforementioned data monitoring-based injection blow molding control methods.

[0101] In the embodiments provided in this application, it should be understood that the computer device, computer program product and computer-readable storage medium provided are all used to perform the corresponding methods provided above, and therefore the beneficial effects they can achieve can be referred to the beneficial effects of the methods provided above, which will not be repeated here.

[0102] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0103] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. A data-monitoring-based injection blow molding control method, characterized in that, The method includes: During the blow molding process, the bubble expansion rate, internal pressure of the preform, volume of the preform, mold temperature, and wall thickness of the preform at each sampling point are obtained at each sampling time. Based on the abrupt changes in the rate of change of internal pressure of the billet over time and the instantaneous increase in the rate of bubble expansion at each sampling moment, the first division coefficient for each sampling moment is determined; based on the temporal increase of the first division coefficient for each sampling moment over time, the start time of the expansion stage is determined; based on the standard deviation of the billet volume at the start time of the expansion stage, the control parameters for the expansion stage are determined; the first division coefficient is used to reflect the probability that the sampling moment is in the expansion stage. The start time of the shaping stage is determined based on the temporal decrease of the first division coefficient at each sampling time after the start time of the expansion stage; the control parameters of the shaping stage are determined based on the standard deviation of the blank wall thickness at all monitoring points at the start time of the shaping stage. Based on the uniformity of the blank wall thickness distribution and the standard deviation of the blank volume at each monitoring point after the start of the shaping stage, a second division coefficient is determined for each sampling point. The start time of the cooling stage is determined based on the second division coefficient. The cooling stage control parameters are determined based on the overall blank wall thickness at all monitoring points and the corresponding mold temperature at the start time of the cooling stage. The cooling stage control parameter is the cooling time of the cooling stage. The second division coefficient is used to reflect the probability that the sampling point is in the cooling stage. The blow molding parameters are adjusted according to the expansion stage control parameters, the shaping stage control parameters, and the cooling stage control parameters; Cooldown time satisfies the following formula: ； in, This refers to the cooling time during the cooling phase. To preset the a priori cooling time, The start time of the cooling phase The mold temperature below, To test the cooling water temperature first, The start time of the cooling phase The average thickness of the billet wall at all monitoring points. It is a linear normalization function.

2. The injection blow molding control method based on data monitoring according to claim 1, characterized in that, The process of obtaining the first partitioning coefficient includes: Based on the average internal pressure of the billet at all sampling times prior to each sampling time, the historical reference pressure at each sampling time is determined; based on the difference between the internal pressure of the billet at each sampling time and the historical reference pressure, the historical pressure change value at each sampling time is determined; the difference between the internal pressure of the billet at each sampling time and the internal pressure of the billet at the next sampling time is used as the reference pressure change value at each sampling time; based on the difference between the reference pressure change value and the historical pressure change value, the degree of internal pressure change at each sampling time is determined. The difference between the bubble expansion rate at each sampling time and the bubble expansion rate at the previous sampling time is used to determine the expansion rate increase value at each sampling time. The product between the degree of internal pressure change and the expansion rate increase is normalized to determine the first division coefficient at each sampling time.

3. The injection blow molding control method based on data monitoring according to claim 1, characterized in that, The process of obtaining the start time of the expansion phase includes: In terms of time sequence, the next sampling moment after the sampling moment when the first dividing coefficient is greater than the preset expansion threshold is taken as the start moment of the expansion phase.

4. The injection blow molding control method based on data monitoring according to claim 1, characterized in that, The process of obtaining the control parameters for the expansion phase includes: The positive correlation mapping value between the blank volume at the beginning of the expansion stage and the standard mold capacity is used as the expansion stage control weight at the beginning of the expansion stage. The expansion stage blowing pressure is determined by the product of the expansion stage control weight and the preset initial blowing pressure; the expansion stage mold temperature is determined by the product of the expansion stage control weight and the preset initial mold temperature. The blowing pressure and the mold temperature during the expansion stage are used as the control parameters for the expansion stage.

5. The injection blow molding control method based on data monitoring according to claim 1, characterized in that, The process of obtaining the start time of the finalization stage includes: After the start of the expansion phase, the next sampling time after the sampling time when the first division coefficient is less than the preset shaping threshold for the first time in the time sequence is taken as the start time of the shaping phase.

6. The injection blow molding control method based on data monitoring according to claim 4, characterized in that, The process of obtaining the control parameters during the finalization stage includes: The minimum wall thickness of the preform at all monitoring points at the start of the shaping stage is positively correlated with the difference between the preset plastic sample thickness, and the shaping stage control weight at the start of the shaping stage is determined. The blowing pressure in the shaping stage is determined by the product of the control weight in the shaping stage and the blowing pressure in the expansion stage; the mold temperature in the shaping stage is determined by the product of the negative correlation mapping value of the control weight in the shaping stage and the mold temperature in the expansion stage. The blowing pressure and mold temperature during the shaping stage are used as the control parameters for the shaping stage.

7. The injection blow molding control method based on data monitoring according to claim 1, characterized in that, The process of obtaining the second partitioning coefficient includes: After the start of the shaping stage, the difference between the blank volume and the standard capacity of the mold at each sampling time is used as the volume standard deviation value at each sampling time. The product of the variance of the blank wall thickness at all monitoring points at each sampling time and the volume standard deviation is normalized to determine the second division coefficient at each sampling time.

8. The injection blow molding control method based on data monitoring according to claim 1, characterized in that, The process of obtaining the start time of the cooling phase includes: After the start of the finalization stage, the sampling time when the second division coefficient is less than the preset cooling threshold for the first time in the time sequence is taken as the start time of the cooling stage.

9. The injection blow molding control method based on data monitoring according to claim 1, characterized in that, The process of obtaining the control parameters for the cooling stage includes: The average thickness of the blank wall at all monitoring points at the start of the cooling stage is taken as the degree of thermal conductivity influence of the thickness; the difference between the mold temperature and the prior cooling water temperature at the start of the cooling stage is taken as the thermal conductivity reference temperature difference; the normalized value of the product between the degree of thermal conductivity influence of the thickness and the thermal conductivity reference temperature difference is positively correlated to determine the cooling stage control weight at the start of the cooling stage. The cooling time of the cooling stage is determined by multiplying the cooling stage control weight by the preset prior cooling duration; the cooling time of the cooling stage is used as the cooling stage control parameter.

10. A data-monitoring-based injection blow molding control system, characterized in that, The system includes: The data acquisition module is used to acquire the bubble expansion rate, internal pressure of the preform, volume of the preform, mold temperature, and wall thickness of the preform at each sampling point during the blow molding process. The expansion stage control parameter determination module is used to determine the first division coefficient for each sampling moment based on the abrupt change in the rate of change of the internal pressure of the billet in the time sequence and the instantaneous increase in the bubble expansion rate at each sampling moment; to determine the start time of the expansion stage based on the temporal increase of the first division coefficient at each sampling moment in the time sequence; and to determine the expansion stage control parameters based on the standard deviation of the billet volume at the start time of the expansion stage; the first division coefficient is used to reflect the probability that the sampling moment is in the expansion stage. The module for determining the control parameters of the shaping stage is used to determine the start time of the shaping stage based on the temporal decrease of the first division coefficient at each sampling time after the start time of the expansion stage; and to determine the control parameters of the shaping stage based on the standard deviation of the billet wall thickness at all monitoring points at the start time of the shaping stage. The cooling stage control parameter determination module is used to determine the second division coefficient at each sampling time based on the uniformity of the blank wall thickness distribution and the standard deviation of the blank volume at each monitoring point after the start of the shaping stage; determine the start time of the cooling stage based on the second division coefficient; determine the cooling stage control parameters based on the overall blank wall thickness at all monitoring points and the corresponding mold temperature at the start time of the cooling stage; the cooling stage control parameter is the cooling time of the cooling stage; the second division coefficient is used to reflect the probability that the sampling time is in the cooling stage; The blow molding parameter adjustment module is used to adjust the blow molding parameters according to the expansion stage control parameters, the shaping stage control parameters, and the cooling stage control parameters; Cooldown time satisfies the following formula: ； in, This refers to the cooling time during the cooling phase. To preset the a priori cooling time, The start time of the cooling phase The mold temperature below, To test the cooling water temperature first, The start time of the cooling phase The average thickness of the billet wall at all monitoring points. It is a linear normalization function.

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