A mold injection molding control system and control method thereof

Abstract

The present invention relates to the field of plastic processing control technology, and specifically to a mold injection molding control system and a control method thereof. The method first obtains the plastic leveling anomaly of the injection molding cycle according to the fluctuation of the barrel temperature time series data and the difference of the local temperature of all sampling points; obtains the response anomaly corresponding to the current injection molding cycle according to the difference of the injection molding quality parameters corresponding to the current injection molding cycle and each historical injection molding cycle, and the difference between the system efficiency indicators; controls the injection pressure value of each injection stage in the next injection molding cycle according to the plastic leveling anomaly, response anomaly and injection pressure values ​​of each injection stage corresponding to the current injection molding cycle. In the embodiment of the present invention, the effect of controlling the mold injection molding process of the next injection molding cycle is improved by analyzing the leveling state of the molten plastic in the mold and the control system response speed.

Description

Technical Field

[0001] The invention relates to the technical field of plastic processing control, and in particular to a mold injection processing control system and a control method thereof. Background Art

[0002] Injection molding is a plastic molding process that uses a mold as a molding tool to inject molten plastic raw materials into the mold cavity through the high pressure of the injection molding machine, and obtains the desired shape of the plastic product after cooling and solidification. In order to ensure the production of high-quality plastic products, it is necessary to effectively control the injection pressure value during the injection molding process.

[0003] The prior art adjusts the injection pressure value through a feedback control system. The feedback control system compares the actual injection pressure during the real-time monitoring of the injection process with the set value, and makes timely adjustments when there is a deviation, thereby ensuring that the injection pressure is stable at the set value. In the process of adjusting the injection pressure in the prior art, there is an impact of the long-term operation of the injection molding machine. Even if the injection pressure is adjusted by the feedback control system, there are still problems such as the difficulty of the plastic melt to uniformly fill the mold and the untimely response of the system, which affects the product quality and production efficiency, resulting in poor control of the mold injection molding process. Summary of the invention

[0004] In order to solve the technical problem that the prior art has poor control effect on mold injection molding, the purpose of the present invention is to provide a mold injection molding control system and a control method thereof. The technical solution adopted is as follows:

[0005] A mold injection molding process control method, the method comprising:

[0006] Obtaining an injection molding data set corresponding to the current injection molding cycle and an injection molding data set corresponding to each historical injection molding cycle; the injection molding data set includes: barrel temperature time series data, injection speed time series data, local temperature at each sampling point on the mold, injection molding part quality parameters, and injection pressure values ​​at each injection stage;

[0007] According to the fluctuation of the barrel temperature time series data and the difference of the local temperature of all sampling points, the plastic leveling abnormality of the injection molding cycle is obtained; according to the duration of the injection molding cycle and the overall distribution of the injection speed time series data, the system efficiency index of the injection molding cycle is obtained; according to the difference of the quality parameters of the injection molded parts corresponding to the current injection molding cycle and each historical injection molding cycle, and the difference between the system efficiency indexes, the corresponding response abnormality of the current injection molding cycle is obtained;

[0008] According to the plastic leveling abnormality, response abnormality and injection pressure values ​​of each injection stage corresponding to the current injection cycle, the injection pressure value of each injection stage in the next injection cycle is controlled.

[0009] Furthermore, the method for obtaining the plastic leveling abnormality includes:

[0010] According to the fluctuation of the local amplitude in the barrel temperature time series data, the barrel temperature fluctuation parameter of the injection molding cycle is obtained;

[0011] According to the difference in the local temperatures of all the sampling points on the mold, a mold temperature non-uniformity parameter of the injection molding cycle is obtained;

[0012] The plastic leveling anomaly of the injection molding cycle is obtained according to the barrel temperature fluctuation parameter and the mold temperature unevenness parameter; the barrel temperature fluctuation parameter and the mold temperature unevenness parameter are both positively correlated with the plastic leveling anomaly.

[0013] Furthermore, the method for obtaining the barrel temperature fluctuation parameter includes:

[0014] Acquire all peak points and all valley points in the barrel temperature time series data; use all the peak points and all the valley points as all extreme points to be analyzed;

[0015] According to the difference between each extreme value point to be analyzed and its previous extreme value point to be analyzed in time series, the change amplitude parameter of the extreme value point to be analyzed is obtained;

[0016] The barrel temperature fluctuation parameter of the injection molding cycle is obtained according to the fluctuation of the variation amplitude parameter of all extreme value points to be analyzed.

[0017] Furthermore, the method for obtaining the mold temperature unevenness parameter includes:

[0018] According to the difference of the local temperatures of each two sampling points, obtaining a local temperature difference parameter of each two sampling points;

[0019] The mold temperature non-uniformity parameter of the injection molding cycle is obtained according to the overall distribution of all the local temperature difference parameters on the mold.

[0020] Furthermore, the method for obtaining the system efficiency index includes:

[0021] According to the deviation between the duration of the injection molding cycle and the preset standard duration, the time deviation parameter of the injection molding cycle is obtained;

[0022] According to the overall distribution of injection speed in the injection speed time series data, the overall injection speed parameters of the injection cycle are obtained;

[0023] The system efficiency index of the injection molding cycle is obtained according to the time deviation parameter and the overall injection speed parameter; the time deviation parameter and the system efficiency index are positively correlated; the overall injection speed parameter and the system efficiency index are negatively correlated.

[0024] Furthermore, the method for obtaining the overall injection speed parameter includes:

[0025] Calculate the mean of all injection speeds in the injection speed time series data to obtain the overall injection speed parameters of the injection cycle.

[0026] Furthermore, the method for obtaining the response abnormality degree includes:

[0027] Obtain overall quality parameters based on the overall distribution of quality parameters of injection molded parts corresponding to all historical injection molding cycles;

[0028] Obtain overall efficiency parameters based on the overall distribution of system efficiency indicators corresponding to all historical injection cycles;

[0029] Obtaining a quality difference factor according to the difference between the injection molded part quality parameter and the overall quality parameter in the current injection molding cycle;

[0030] According to the difference between the system efficiency index and the overall efficiency parameter of the current injection molding cycle, an efficiency difference factor is obtained;

[0031] According to the quality difference factor and the efficiency difference factor, the response abnormality corresponding to the current injection molding cycle is obtained; the quality difference factor and the response abnormality are negatively correlated; the efficiency difference factor and the response abnormality are positively correlated.

[0032] Furthermore, the method for obtaining the quality difference factor includes:

[0033] The absolute value of the difference between the injection molded part quality parameter and the overall quality parameter of the current injection molding cycle is calculated to obtain a quality difference factor.

[0034] Furthermore, the method for obtaining the injection pressure value of each injection stage in the next injection molding cycle includes:

[0035] According to the plastic leveling abnormality and the response abnormality, the corresponding adjustment parameters of the current injection molding cycle are obtained; the plastic leveling abnormality and the response abnormality are both positively correlated with the adjustment parameters;

[0036] According to the injection pressure value and adjustment parameters of each injection stage in the current injection molding cycle, the injection pressure value of each injection stage in the next injection molding cycle is obtained.

[0037] The present invention proposes a mold injection molding process control system, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements any one of the steps of the mold injection molding process control method when executing the computer program.

[0038] The present invention has the following beneficial effects:

[0039] As the injection molding machine runs for a long time, it is difficult to set the injection pressure to ensure that the plastic fills the mold evenly and the efficiency of the system, which in turn affects the continuity of production and the consistency of the product. Considering that the plastic is heated and melted in the barrel and then injected into the mold, if the molten plastic does not achieve the expected effect, insufficient leveling is likely to occur in the mold, which has a greater impact on the quality of the plastic product. The plastic leveling abnormality of the injection molding cycle is obtained. The greater the plastic leveling abnormality, the worse the leveling state of the molten plastic in the mold, and the greater the impact on the quality of the plastic product. Considering that the injection molding cycle is long and the working state of the push rod is relatively slow, it means that the control system efficiency is low and it takes longer to consume time. The system efficiency index is obtained. The system efficiency index initially reflects the untimely response speed of the control system. Considering that the current injection molding cycle and the historical injection molding cycle have little difference in the injection molding quality parameters, but there is a significant difference in the system efficiency index, the response abnormality can more truly reflect the untimely response of the system. The greater the response abnormality, the lower the system efficiency. By detecting the abnormality of the leveling of the molten plastic in the mold and the abnormality of the response of the system when it is not in time, the injection pressure of the next injection molding cycle can be adjusted to improve the effect of controlling the mold injection molding process. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 A flow chart of a mold injection molding control method provided by one embodiment of the present invention;

[0042] Figure 2 A flow chart of a method for obtaining plastic leveling anomaly provided by an embodiment of the present invention;

[0043] Figure 3 A flow chart of a method for obtaining barrel temperature fluctuation parameters provided by one embodiment of the present invention;

[0044] Figure 4 A flow chart of a method for obtaining mold temperature unevenness parameters provided by an embodiment of the present invention;

[0045] Figure 5 A structural diagram of a mold injection molding control system provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0046] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of a mold injection molding control system and a control method thereof proposed according to the present invention, its specific implementation, structure, features and effects, in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0047] Unless defined otherwise, 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 belongs.

[0048] The specific scheme of a mold injection molding control system and a control method thereof provided by the present invention is described in detail below with reference to the accompanying drawings.

[0049] The embodiment of the present invention provides a mold injection molding process control system and a control method thereof, please refer to Figure 1 , which shows a flow chart of a mold injection molding control method provided by an embodiment of the present invention, the method comprising the following steps:

[0050] Step S1: Obtain the injection molding data set corresponding to the current injection molding cycle and the injection molding data set corresponding to each historical injection molding cycle; the injection molding data set includes: barrel temperature timing data, injection speed timing data, local temperature at each sampling point on the mold, injection molding part quality parameters and injection pressure values ​​at each injection stage.

[0051] The main purpose of the present invention is to adjust the injection pressure during the mold injection molding process to ensure the effect of controlling the mold injection molding process. First, data needs to be obtained.

[0052] The injection molding process refers to placing granular or powdered plastic in the barrel of an injection molding machine and heating it to a molten state. After the plastic is completely melted, a push rod is used in the injection molding machine to apply injection pressure to the molten plastic raw material so that the molten plastic raw material is filled into the mold. After cooling and solidification, the plastic product is demolded. Among them, the injection molding cycle refers to the time required to complete an injection molding process in the injection molding process, usually including the process from mold filling to demolding.

[0053] The barrel heats the plastic as a preliminary preparation for the injection molding cycle, and the stability of the barrel temperature is related to the product quality. The barrel temperature timing data corresponding to the injection molding cycle is obtained from the monitoring system of the injection molding machine. The specific steps include: installing a temperature sensor on the barrel, sampling the barrel temperature according to the preset sampling frequency during the entire process of the barrel heating the plastic, sequentially counting the barrel temperature corresponding to each sampling moment, obtaining the barrel temperature timing data, and uploading the barrel temperature timing data to the monitoring system. It should be noted that the injection molding cycle usually does not include the barrel heating plastic process. The preliminary preparation work of each injection molding cycle requires the barrel heating plastic process, and each injection molding cycle has a corresponding barrel heating plastic process.

[0054] In order to monitor the speed of injecting molten plastic into the mold during the injection molding cycle, the injection speed timing data of the injection molding cycle is obtained from the monitoring system of the injection molding machine. The specific steps include: installing a speed sensor at the push rod of the injection molding machine, sampling the injection speed according to a preset sampling frequency during the injection molding cycle, counting the injection speed corresponding to each sampling moment in turn, obtaining the injection speed timing data, and uploading the injection speed timing data to the monitoring system.

[0055] In order to monitor the uniform distribution of molten plastic raw materials in the mold, the local temperature of each sampling point on the mold during the injection molding cycle is obtained from the monitoring system of the injection molding machine. The specific steps include: installing multiple thermistor sensors on the mold surface, and using the temperature detected by each thermistor sensor as the local temperature of each sampling point. When the molten plastic is completely injected into the mold during the injection molding cycle, the local temperature of each sampling point on the mold is transmitted to the monitoring system.

[0056] In order to analyze the quality of plastic products produced during the injection cycle, the quality parameters of injection molded parts are obtained from the monitoring system of the injection machine. The larger the quality parameters of injection molded parts, the better the quality of the plastic products. The specific steps include: capturing images of the plastic products after demolding corresponding to the injection cycle to obtain images of plastic products. It should be noted that CNN neural network is a technical means well known to those skilled in the art, and will not be described in detail here. Only a brief description of the process of using CNN neural network to determine the quality parameters of injection molded parts of plastic product images in one embodiment of the present invention is given:

[0057] A CNN neural network is trained using a reference data set, which includes multiple images of plastic products. Since the images of plastic products include characteristic information of plastic products, such as the size and shape, surface quality and specific defects of plastic products, the images of plastic products are scored from 0 to 1 as the quality parameters of injection molded parts of the images of plastic products, wherein the better the quality of the plastic products, the higher the quality parameters of injection molded parts; then the labeled data set is divided into a training set and a validation set according to a preset ratio, the reference data set is input into the CNN neural network for training, the loss function is cross entropy, and the gradient descent method is used until the loss function converges to obtain a trained CNN neural network; each image of plastic products is input into the trained CNN neural network to obtain the quality parameters of injection molded parts of the images of plastic products, that is, to obtain the quality parameters of injection molded parts corresponding to the injection cycle. In an embodiment of the present invention, the preset ratio is 7:3, and the implementer can set it according to the implementation scenario.

[0058] In order to adjust the injection pressure later, it is necessary to monitor the injection pressure applied by the push rod to the molten plastic raw material, and obtain the injection pressure values ​​of each injection stage of the injection molding cycle from the monitoring system of the injection molding machine. The present invention takes an injection molding machine using a multi-stage injection pressure control method as an example. The injection pressure values ​​of each injection stage of the injection molding cycle of the present invention are: the injection pressure value of the low-speed and low-pressure injection stage, the injection pressure value of the medium-speed and medium-pressure injection stage, and the injection pressure value of the high-speed and high-pressure injection stage. Among them, different injection stages use different set injection pressure values. For example, in the low-speed and low-pressure injection stage, it is mainly used to fill the gate and the initial part of the mold cavity. In order to prevent the melt from flowing too fast, a lower injection pressure value is used; in the medium-speed and medium-pressure injection stage, as the mold cavity is gradually filled, a moderate injection pressure value is used to ensure that the melt can quickly and evenly fill the cavity; in the high-speed and high-pressure injection stage, when approaching the end of the mold cavity, a higher injection pressure value is used to quickly fill the remaining space and compact the melt.

[0059] Specifically, the injection molding cycle corresponding to the barrel temperature time series data, injection speed time series data, local temperature at each sampling point on the mold, injection molded part quality parameters and injection pressure values ​​at each injection stage are used as the injection molding cycle corresponding injection molding data set. The current injection molding cycle corresponding injection molding data set and each historical injection molding cycle corresponding injection molding data set are obtained from the monitoring system of the injection molding machine. Among them, in the present invention, the previous injection molding cycle corresponding to the injection molding data set at the current moment is used as the current injection molding cycle corresponding injection molding data set. The injection molding data sets corresponding to each injection molding cycle before the current injection molding cycle are used as the injection molding data sets corresponding to each historical injection molding cycle. It should be noted that, in one embodiment of the present invention, sampling is performed according to a preset frequency, and each sampling is used as a sampling moment, and the preset frequency is 1 time / second. It should be noted that, in order to facilitate calculations, all indicator data involved in the calculations in the embodiment of the present invention are subjected to data preprocessing, thereby eliminating the dimension effect. The specific means of removing the dimension effect are technical means well known to those skilled in the art, and are not limited here.

[0060] Considering that with the long-term operation of the injection molding machine, it is difficult to set the injection pressure value to cope with the changes in processing conditions, and it is difficult to ensure that the plastic fills the mold and the efficiency of the system uniformly, thereby affecting the continuity of production and the consistency of the product. The present invention analyzes the leveling state of the molten plastic in the mold and the control system response speed in the current injection molding cycle, and then adjusts the injection pressure to improve the effect of the mold injection molding process in the next injection molding cycle.

[0061] Step S2: According to the fluctuation of the barrel temperature time series data and the difference of the local temperature of all sampling points, the plastic leveling anomaly of the injection molding cycle is obtained; according to the duration of the injection molding cycle and the overall distribution of the injection speed time series data, the system efficiency index of the injection molding cycle is obtained; according to the difference of the injection molding quality parameters corresponding to the current injection molding cycle and each historical injection molding cycle, as well as the difference between the system efficiency indexes, the corresponding response anomaly of the current injection molding cycle is obtained.

[0062] In order to analyze the uniform filling of the mold by plastic in the current injection molding cycle and the response speed of the control system, considering that the plastic is heated and melted in the barrel and then injected into the mold, if the molten plastic does not achieve the expected effect, insufficient leveling is likely to occur in the mold, which has a greater impact on the quality of the plastic product, and the plastic leveling abnormality of the injection molding cycle is obtained. The greater the plastic leveling abnormality, the worse the leveling state of the molten plastic in the mold, and the greater the impact on the quality of the plastic product. Considering that the injection molding cycle is long and the working state of the push rod is relatively slow, it means that the control system efficiency is low and it takes longer to obtain the system efficiency index. The system efficiency index preliminarily reflects the untimely response speed of the control system. Considering that the current injection molding cycle and the historical injection molding cycle have little difference in the injection molding quality parameters, but there is a significant difference in the system efficiency index, the response abnormality can more truly reflect the untimely response of the system. The greater the response abnormality, the lower the system efficiency.

[0063] See also Figure 2 , which shows a flow chart of a method for obtaining plastic leveling abnormality in one embodiment of the present invention. Preferably, in one embodiment of the present invention, the plastic leveling abnormality of the injection molding cycle is obtained by analyzing the melting state of the plastic in the barrel and the leveling state of the molten plastic in the mold. The greater the plastic leveling abnormality, the more uneven the distribution of the molten plastic in the mold, and the greater the impact on the quality of the plastic product. The method for obtaining the plastic leveling abnormality includes:

[0064] Step S201: Obtain barrel temperature fluctuation parameters of an injection molding cycle according to fluctuations in local amplitudes in barrel temperature time series data.

[0065] Considering that in the process of injection molding, the plastic or granules need to be heated to a molten state in the barrel first, the barrel temperature needs to be kept stable during this process. If the barrel temperature fluctuates, it is easy to cause the plastic to be in a poor molten state, which in turn affects the leveling of the injection molding process. The barrel temperature fluctuation parameter of the injection molding cycle is obtained. The larger the barrel temperature fluctuation parameter, the lower the stability of the barrel temperature, which is more likely to affect the leveling of the injection molding process. Please refer to Figure 3 , which shows a flow chart of a method for obtaining a barrel temperature fluctuation parameter in one embodiment of the present invention. In one embodiment of the present invention, the method for obtaining a barrel temperature fluctuation parameter includes:

[0066] Step S211: Acquire all peak points and all valley points in the barrel temperature time series data; and use all peak points and all valley points as all extreme points to be analyzed.

[0067] The extreme point to be analyzed reflects the extreme value in the barrel temperature time series data.

[0068] In one embodiment of the present invention, the AMDP peak detection algorithm (Amplitude Modulation DepthPeak Detection Algorithm) is used to obtain all peak points in the barrel temperature time series data, and the barrel temperature corresponding to the minimum value between adjacent peak points is used as the valley point; all peak points and all valley points are used as all extreme points to be analyzed. It should be noted that the AMDP peak detection algorithm is a prior art well known to those skilled in the art and will not be described in detail here.

[0069] Step S212: obtaining a variation amplitude parameter of the extreme value point to be analyzed according to the difference between each extreme value point to be analyzed and its previous extreme value point to be analyzed in time sequence.

[0070] The variation amplitude parameter reflects the local fluctuation amplitude of the data in the barrel temperature time series data. The larger the variation amplitude parameter is, the larger the local fluctuation amplitude of the data is.

[0071] In one embodiment of the present invention, all extreme value points to be analyzed are sorted in time sequence, and the absolute value of the difference between each extreme value point to be analyzed and its previous extreme value point to be analyzed in time sequence is calculated to obtain the change amplitude parameter of the extreme value point to be analyzed, and the difference is reflected by the absolute value of the difference.

[0072] Step S213: Obtain barrel temperature fluctuation parameters of the injection molding cycle according to the fluctuation of the variation amplitude parameters of all extreme value points to be analyzed.

[0073] The barrel temperature fluctuation parameter is reflected in the fluctuation state of the local fluctuation amplitude value of the data in the barrel temperature time series data. The larger the barrel temperature fluctuation parameter is, the greater the fluctuation state of the local fluctuation amplitude value of the data is, which is more likely to cause poor melting state of the plastic, and thus more likely to affect the leveling of the injection molding process.

[0074] In one embodiment of the present invention, the variance of the variation amplitude parameters of all extreme value points to be analyzed is calculated to obtain the barrel temperature fluctuation parameter of the injection molding cycle, and the fluctuation is reflected by the variance.

[0075] Step S202: Obtain mold temperature non-uniformity parameters during the injection molding cycle according to the degree of difference in local temperature at all sampling points on the mold.

[0076] Considering that molten plastic has high temperature, when the molten plastic is completely injected into the mold during the injection cycle, the more uneven the distribution of the molten plastic in the mold is, the more likely it is to cause uneven mold surface temperature. The mold temperature unevenness parameter is obtained. The larger the mold temperature unevenness parameter is, the worse the leveling effect of the molten plastic in the mold is, and the greater the impact on the quality of the plastic product is. Please refer to Figure 4, which shows a flow chart of a method for obtaining a mold temperature unevenness parameter in one embodiment of the present invention. In one embodiment of the present invention, the method for obtaining a mold temperature unevenness parameter includes:

[0077] Step S221: according to the difference of the local temperatures between every two sampling points, obtain the local temperature difference parameter between every two sampling points.

[0078] The larger the local temperature difference parameter is, the greater the local surface temperature difference of the mold is when the molten plastic is completely injected into the mold during the injection molding cycle.

[0079] In one embodiment of the present invention, the absolute value of the difference between the local temperatures of every two sampling points is calculated to obtain the local temperature difference parameter of every two sampling points.

[0080] Step S222: Obtain mold temperature non-uniformity parameters during the injection molding cycle according to the overall distribution of all local temperature difference parameters on the mold.

[0081] The larger the mold temperature unevenness parameter is, the greater the difference in the overall surface temperature of the mold when the molten plastic is completely injected into the mold during the injection cycle, the more likely the mold surface temperature is to be uneven, the worse the leveling effect of the molten plastic in the mold is, and the greater the impact on the quality of the plastic product.

[0082] In one embodiment of the present invention, the mean value of all local temperature difference parameters on the mold is calculated to obtain the mold temperature non-uniformity parameter of the injection molding cycle.

[0083] Step S203: Obtain the plastic leveling anomaly during the injection molding cycle according to the barrel temperature fluctuation parameter and the mold temperature unevenness parameter; the barrel temperature fluctuation parameter and the mold temperature unevenness parameter are both positively correlated with the plastic leveling anomaly.

[0084] The plastic leveling anomaly of the injection molding cycle is obtained by combining the barrel temperature fluctuation parameters and the mold temperature unevenness parameters. The greater the plastic leveling anomaly, the worse the leveling effect of the molten plastic in the mold, which affects the quality of the plastic product.

[0085] In one embodiment of the present invention, the product of the barrel temperature fluctuation parameter and the mold temperature unevenness parameter is calculated to obtain the plastic leveling abnormality of the injection molding cycle. In this embodiment of the present invention, the expression of the plastic leveling abnormality is:

[0086]

[0087] In the formula, It is the abnormality of plastic leveling during the injection molding cycle; is the barrel temperature fluctuation parameter during the injection molding cycle; It is the mold temperature unevenness parameter during the injection molding cycle.

[0088] At this point, the plastic leveling anomaly is obtained.

[0089] Considering that the injection molding cycle is long and the push rod is in a slow working state, it means that the control system is inefficient and takes longer time to obtain the system efficiency index. The larger the system efficiency index is, the longer it takes for the control system to respond. Preferably, in one embodiment of the present invention, the method for obtaining the system efficiency index includes:

[0090] According to the deviation between the duration of the injection molding cycle and the preset standard duration, the time deviation parameter of the injection molding cycle is obtained;

[0091] According to the overall distribution of injection speed in the injection speed time series data, the overall injection speed parameters of the injection cycle are obtained;

[0092] According to the time deviation parameter and the overall injection speed parameter, the system efficiency index of the injection molding cycle is obtained; the time deviation parameter and the system efficiency index are positively correlated; the overall injection speed parameter and the system efficiency index are negatively correlated.

[0093] The larger the time deviation parameter is, the longer the injection cycle takes than expected, and the more likely the system response is not timely. The smaller the overall injection speed parameter is, the slower the working state of the push rod is. Based on the time deviation parameter and the overall injection speed parameter, the system efficiency index of the injection cycle is obtained. The larger the system efficiency index is, the longer the injection cycle takes and the slower the response speed is.

[0094] For the above steps, specifically, calculate the ratio of the duration of the injection molding cycle to the preset standard duration, obtain the time deviation parameter of the injection cycle, and reflect the deviation through the ratio. Calculate the mean of all injection speeds in the injection speed time series data to obtain the overall injection speed parameter of the injection cycle. Calculate the ratio of the time deviation parameter and the overall injection speed parameter to obtain the system efficiency index of the injection molding cycle. In one embodiment of the present invention, the preset standard duration is 32, and the implementer can set it according to the implementation scenario. For example, when the mold has a larger size, the preset standard duration can be appropriately increased. In an embodiment of the present invention, the expression of the system efficiency index is:

[0095]

[0096] In the formula, It is the system efficiency indicator of the injection molding cycle; is the duration of the injection molding cycle; The preset standard duration; In the injection speed time series data, Injection speed; is the total number of all injection speeds in the injection speed time series data; is the time deviation parameter of the injection cycle; It is the overall injection speed parameter of the injection cycle.

[0097] Among them, the larger the time deviation parameter is, the longer the injection cycle takes than expected, and the more likely it is that the control system will not respond in time during the mold injection process; the smaller the overall injection speed parameter is, the slower the push rod works; since the injection cycle is longer and the push rod works more slowly, it means that the control system efficiency is lower and it takes a longer time to obtain the system efficiency index. The larger the system efficiency index is, the longer it takes for the control system to respond.

[0098] The system efficiency index preliminarily reflects the untimely response speed of the control system. Since the system efficiency index may be affected by other factors and may not be entirely derived from the response speed of the control system, it is necessary to further verify the response speed of the control system and obtain the response abnormality.

[0099] Considering that the difference in quality parameters of injection molded parts in the current injection molding cycle is smaller than that in multiple injection molding cycles in history, this means that the system maintains good stability and consistency in terms of quality control. At the same time, when these injection molding quality parameters are close, there are significant differences in system efficiency indicators, which means that as the injection molding machine runs for a long time, the system response effect speed slows down. When it is observed that the current injection molding cycle and the historical injection molding cycles have little difference in injection molding quality parameters, but there are significant differences in system efficiency indicators, the response abnormality can more truly reflect the situation of untimely system response. Preferably, in one embodiment of the present invention, the method for obtaining the response abnormality includes:

[0100] Obtain overall quality parameters based on the overall distribution of quality parameters of injection molded parts corresponding to all historical injection molding cycles;

[0101] Obtain overall efficiency parameters based on the overall distribution of system efficiency indicators corresponding to all historical injection cycles;

[0102] According to the difference between the quality parameters of the injection molded parts and the overall quality parameters of the current injection molding cycle, the quality difference factor is obtained;

[0103] According to the difference between the system efficiency index and the overall efficiency parameter of the current injection molding cycle, the efficiency difference factor is obtained;

[0104] According to the quality difference factor and the efficiency difference factor, the corresponding response abnormality of the current injection molding cycle is obtained; the quality difference factor and the response abnormality are negatively correlated; the efficiency difference factor and the response abnormality are positively correlated.

[0105] For the above steps, specifically, calculate the mean of the injection molded parts quality parameters corresponding to all historical injection molding cycles to obtain the overall quality parameters. Calculate the mean of the system efficiency index corresponding to all historical injection molding cycles to obtain the overall efficiency parameters. Calculate the absolute value of the difference between the injection molded parts quality parameters of the current injection molding cycle and the overall quality parameters to obtain the quality difference factor. Calculate the absolute value of the difference between the system efficiency index of the current injection molding cycle and the overall efficiency parameter to obtain the efficiency difference factor. Calculate the sum of the quality difference factor and the denominator adjustment factor, calculate the ratio of the efficiency difference factor to the sum, and obtain the response anomaly corresponding to the current injection molding cycle. In one embodiment of the present invention, the denominator adjustment factor is used to ensure that the denominator is not 0. The denominator adjustment factor is a number greater than 0. This embodiment sets it to 0.01, and the implementer can set it according to the implementation scenario. In an embodiment of the present invention, the expression of the response anomaly is:

[0106]

[0107] In the formula, The abnormal response degree corresponding to the current injection molding cycle; It is the system efficiency index of the current injection molding cycle; is the overall efficiency parameter; The quality parameters of the injection molded parts in the current injection molding cycle; is the overall quality parameter; is the efficiency difference factor; is the quality difference factor; is the denominator adjustment factor.

[0108] At this point, the corresponding response abnormality of the current injection cycle is obtained.

[0109] Step S3: According to the plastic leveling abnormality, response abnormality and injection pressure values ​​of each injection stage corresponding to the current injection molding cycle, the injection pressure value of each injection stage in the next injection molding cycle is controlled.

[0110] The above steps are used to determine the plastic leveling anomaly that can reflect the leveling state of the molten plastic in the mold and the response anomaly that the system does not respond in time, and then adjust the injection pressure of the next injection molding cycle to improve the effect of controlling the mold injection molding process.

[0111] Preferably, in one embodiment of the present invention, the method for obtaining the injection pressure value of each injection stage in the next injection molding cycle includes:

[0112] According to the plastic leveling abnormality and response abnormality, the corresponding adjustment parameters of the current injection molding cycle are obtained; the plastic leveling abnormality and response abnormality are positively correlated with the adjustment parameters;

[0113] According to the injection pressure value and adjustment parameters of each injection stage in the current injection molding cycle, the injection pressure value of each injection stage in the next injection molding cycle is obtained.

[0114] In the process of using the control system to control and adjust the mold injection molding process, it is necessary to accurately set the adjustment parameters to ensure that the plastic fills the mold evenly and the system responds in time. Considering that the greater the plastic leveling abnormality, the worse the leveling state of the molten plastic in the mold, the more it affects the quality of the plastic product. The greater the response abnormality, the less timely the system response. The poor leveling state of the molten plastic in the mold is because the molten plastic does not flow to every place and corner of the mold. Increasing the injection pressure will increase the leveling speed of the molten plastic, which can better ensure that the plastic fills the mold evenly. The system responds untimely, and by increasing the injection pressure, the efficiency of the mold injection molding process will be improved. The larger the adjustment parameter, the worse the leveling state of the molten plastic in the mold and the less timely the system responds, the more the injection pressure needs to be increased, and then the injection pressure value of each injection stage in the current injection molding cycle is adjusted according to the adjustment parameter, and the injection pressure value of each injection stage in the next injection molding cycle is obtained, so that the adjusted injection pressure value can improve the effect of the mold injection molding process in the next injection molding cycle.

[0115] Specifically, for the above steps, the square of the plastic leveling anomaly and the square of the response anomaly are calculated to obtain the square sum; the square sum is squared to obtain the square root result, and the square root result is normalized to obtain the adjustment parameter corresponding to the current injection molding cycle. The injection molding data set of the current injection molding cycle also includes the injection pressure value of each injection stage.

[0116] Calculate the sum of 1 and the adjustment parameter, calculate the product of the injection pressure value of each injection stage in the current injection molding cycle and the sum, obtain the injection pressure value of each injection stage in the next injection molding cycle, and use the injection pressure value of each injection stage of the next injection molding cycle to set the injection pressure of each injection stage of the next injection molding cycle, so as to control the mold injection molding process. In one embodiment of the present invention, the normalization method is: normalization is performed using a hyperbolic tangent function to limit the value range to between 0 and 1. Among them, calculating the sum of 1 and the adjustment parameter represents the degree to which the injection pressure needs to be increased on the basis of retaining the original injection pressure value. In this embodiment of the present invention, the injection pressure value of the injection stage of the next injection molding cycle is obtained by the formula:

[0117]

[0118] In the formula, For the next injection cycle Injection pressure value of each injection stage; It is the plastic leveling abnormality of the current injection molding cycle; The abnormal response degree corresponding to the current injection molding cycle; is the hyperbolic tangent function; The current injection cycle Injection pressure value of each injection stage; Corresponding adjustment parameters for the current injection cycle.

[0119] The present invention also proposes a mold injection molding control system, please refer to Figure 5 , which shows a structure diagram of a mold injection molding control system provided by an embodiment of the present invention. The system includes: a data acquisition module 101, an abnormality analysis module 102, and a control module 103.

[0120] The data acquisition module 101 is used to obtain the injection molding data set corresponding to the current injection molding cycle and the injection molding data set corresponding to each historical injection molding cycle; the injection molding data set includes: barrel temperature timing data, injection speed timing data, local temperature at each sampling point on the mold, injection molded part quality parameters and injection pressure values ​​at each injection stage.

[0121] The abnormality analysis module 102 is used to obtain the plastic leveling abnormality of the injection molding cycle according to the fluctuation of the barrel temperature time series data and the difference of the local temperature of all sampling points; to obtain the system efficiency index of the injection molding cycle according to the duration of the injection molding cycle and the overall distribution of the injection speed time series data; to obtain the corresponding response abnormality of the current injection molding cycle according to the difference in the quality parameters of the injection molded parts corresponding to the current injection molding cycle and each historical injection molding cycle, as well as the difference between the system efficiency indicators.

[0122] The control module 103 is used to control the injection pressure value of each injection stage in the next injection molding cycle according to the plastic leveling abnormality, response abnormality and injection pressure value of each injection stage corresponding to the current injection molding cycle.

[0123] In summary, the embodiment of the present invention provides a mold injection molding control system and a control method thereof. First, the plastic leveling anomaly of the injection molding cycle is obtained according to the fluctuation of the barrel temperature time series data and the difference of the local temperature of all sampling points; the system efficiency index of the injection molding cycle is obtained according to the duration of the injection molding cycle and the overall distribution of the injection speed time series data; the response anomaly corresponding to the current injection molding cycle is obtained according to the difference between the quality parameters of the injection molded parts corresponding to the current injection molding cycle and each historical injection molding cycle, as well as the difference between the system efficiency indexes; the injection pressure value of each injection stage in the next injection molding cycle is controlled according to the plastic leveling anomaly, the response anomaly and the injection pressure value of each injection stage corresponding to the current injection molding cycle. In the embodiment of the present invention, the effect of controlling the mold injection molding process of the next injection molding cycle is improved by analyzing the leveling state of the molten plastic in the mold and the control system response speed.

[0124] It should be noted that: the system provided in the above embodiment is only illustrated by the division of the above functional modules. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the computer device is divided into different functional modules to complete all or part of the functions described above. In addition, the mold injection molding control system and the mold injection molding control method embodiment provided in the above embodiment belong to the same concept. The specific implementation process is detailed in the method embodiment and will not be repeated here.

[0125] It should be noted that the sequence of the above embodiments of the present invention is for description only and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0126] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

Claims

1. A mold injection molding control method, characterized in that: The method comprises: Obtaining an injection molding data set corresponding to the current injection molding cycle and an injection molding data set corresponding to each historical injection molding cycle; the injection molding data set includes: barrel temperature time series data, injection speed time series data, local temperature at each sampling point on the mold, injection molding part quality parameters, and injection pressure values ​​at each injection stage; According to the fluctuation of the barrel temperature time series data and the difference of the local temperature of all sampling points, the plastic leveling abnormality of the injection molding cycle is obtained; according to the duration of the injection molding cycle and the overall distribution of the injection speed time series data, the system efficiency index of the injection molding cycle is obtained; according to the difference of the quality parameters of the injection molded parts corresponding to the current injection molding cycle and each historical injection molding cycle, and the difference between the system efficiency indexes, the corresponding response abnormality of the current injection molding cycle is obtained; According to the plastic leveling abnormality, response abnormality and injection pressure values ​​of each injection stage corresponding to the current injection cycle, the injection pressure value of each injection stage in the next injection cycle is controlled; The method for obtaining the plastic leveling abnormality comprises: According to the fluctuation of the local amplitude in the barrel temperature time series data, the barrel temperature fluctuation parameter of the injection molding cycle is obtained; According to the difference in the local temperatures of all the sampling points on the mold, a mold temperature non-uniformity parameter of the injection molding cycle is obtained; According to the barrel temperature fluctuation parameter and the mold temperature unevenness parameter, the plastic leveling abnormality of the injection molding cycle is obtained; the barrel temperature fluctuation parameter and the mold temperature unevenness parameter are both positively correlated with the plastic leveling abnormality; The method for obtaining the barrel temperature fluctuation parameter includes: Acquire all peak points and all valley points in the barrel temperature time series data; use all the peak points and all the valley points as all extreme points to be analyzed; According to the difference between each extreme value point to be analyzed and its previous extreme value point to be analyzed in time series, the change amplitude parameter of the extreme value point to be analyzed is obtained; According to the fluctuation of the variation amplitude parameters of all extreme value points to be analyzed, obtaining the barrel temperature fluctuation parameters of the injection molding cycle; The method for obtaining the mold temperature unevenness parameter includes: According to the difference of the local temperatures of each two sampling points, obtaining a local temperature difference parameter of each two sampling points; According to the overall distribution of all the local temperature difference parameters on the mold, the mold temperature non-uniformity parameter of the injection molding cycle is obtained; The method for obtaining the system efficiency index includes: According to the deviation between the duration of the injection molding cycle and the preset standard duration, the time deviation parameter of the injection molding cycle is obtained; According to the overall distribution of injection speed in the injection speed time series data, the overall injection speed parameters of the injection cycle are obtained; According to the time deviation parameter and the overall injection speed parameter, the system efficiency index of the injection molding cycle is obtained; the time deviation parameter and the system efficiency index are positively correlated; the overall injection speed parameter and the system efficiency index are negatively correlated; The method for obtaining the overall injection speed parameter includes: Calculate the mean of all injection speeds in the injection speed time series data to obtain the overall injection speed parameter of the injection cycle; The method for obtaining the response abnormality degree includes: Obtain overall quality parameters based on the overall distribution of quality parameters of injection molded parts corresponding to all historical injection molding cycles; Obtain overall efficiency parameters based on the overall distribution of system efficiency indicators corresponding to all historical injection cycles; Obtaining a quality difference factor according to the difference between the injection molded part quality parameter and the overall quality parameter in the current injection molding cycle; According to the difference between the system efficiency index and the overall efficiency parameter of the current injection molding cycle, an efficiency difference factor is obtained; According to the quality difference factor and the efficiency difference factor, the response abnormality corresponding to the current injection molding cycle is obtained; the quality difference factor and the response abnormality are negatively correlated; the efficiency difference factor and the response abnormality are positively correlated; The method for obtaining the quality difference factor includes: Calculating the absolute value of the difference between the injection molded part quality parameter and the overall quality parameter in the current injection molding cycle to obtain a quality difference factor; The method for obtaining the injection pressure value of each injection stage in the next injection molding cycle includes: According to the plastic leveling abnormality and the response abnormality, the corresponding adjustment parameters of the current injection molding cycle are obtained; the plastic leveling abnormality and the response abnormality are both positively correlated with the adjustment parameters; According to the injection pressure value and adjustment parameters of each injection stage in the current injection molding cycle, the injection pressure value of each injection stage in the next injection molding cycle is obtained.

2. A mold injection molding control system, 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, the steps of the mold injection molding control method as claimed in claim 1 are implemented.

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