Injection molding control method and system of injection molding machine, storage medium and injection molding machine

Abstract

The invention relates to an injection molding control method and system of an injection molding machine, a storage medium and the injection molding machine, and relates to the technical field of injection molding.The method comprises the steps that according to relevant information of a plastic product, an injection molding strategy corresponding to the relevant information is obtained, and the relevant information comprises the material, the structure and the size of the plastic product; in the process that the injection molding machine works according to the injection molding strategy, the actual injection molding pressure of the injection molding machine is obtained; and according to the actual injection molding pressure and the injection molding stage corresponding to the actual injection molding pressure, the injection molding strategy is updated and executed, and the injection molding stage comprises a filling stage, a pressure maintaining stage and a cooling stage. The injection molding strategy of the injection molding machine is optimized, and the quality of plastic products is improved.

Description

Technical Field

[0001] The present application relates to the field of injection molding technology, and in particular to an injection molding control method, system, storage medium and injection molding machine. Background Art

[0002] Injection molding machine is a kind of equipment that heats and melts plastic particles, injects them into the mold, and solidifies them by cooling. It is used to produce various plastic products such as parts, packaging containers and toys.

[0003] Related Technology When using an injection molding machine for injection molding, it is necessary to first add plastic particles into the barrel, and under the action of a heater, melt the plastic particles to form molten plastic. After that, the molten plastic is injected into the mold. After the injection is completed, the injection molding machine cools the molten plastic in the mold, and after the molten plastic cools and solidifies, the mold is opened to take the plastic product out of the mold.

[0004] With respect to the above-mentioned related technologies, the inventors believe that during the injection molding process, parameters such as injection pressure and injection temperature will affect the quality of the finished plastic products, and these parameters need to be adjusted according to the actual working conditions of the injection molding machine. Summary of the invention

[0005] In order to optimize the injection molding strategy of an injection molding machine and improve the quality of plastic products, the present application provides an injection molding control method, a system, a storage medium and an injection molding machine.

[0006] In a first aspect, the present application provides an injection molding control method of an injection molding machine, which adopts the following technical solution: An injection molding control method for an injection molding machine, comprising: According to the relevant information of the plastic product, an injection molding strategy corresponding to the relevant information is obtained, and the relevant information includes the material, structure and size of the plastic product; When the injection molding machine is working according to the injection molding strategy, the actual injection pressure of the injection molding machine is obtained; The injection strategy is updated and executed according to the actual injection pressure and the injection stage corresponding to the actual injection pressure. The injection stage includes a filling stage, a pressure holding stage and a cooling stage.

[0007] By adopting the above technical solution, the injection molding strategy is updated and executed according to the actual injection molding pressure of the injection molding machine and the injection molding stage corresponding to the actual injection molding pressure. This method allows the injection molding strategy to be adjusted according to the requirements of different injection molding stages, so that the injection molding strategy always meets the requirements and can effectively improve the quality of plastic products.

[0008] Optionally, obtain the timestamp information corresponding to the actual injection pressure; According to the timestamp information, searching for the expected injection pressure corresponding to the timestamp information in the injection strategy; Determine whether the actual injection pressure is consistent with the expected injection pressure; If yes, the injection molding strategy remains unchanged and is executed; If not, the injection molding stage is determined according to the timestamp information; the injection molding strategy is updated according to the actual injection molding pressure and the injection molding stage, and the updated injection molding strategy is executed.

[0009] By adopting the above technical solution, the injection strategy is determined by judging whether the actual injection pressure is consistent with the expected injection pressure, so that the injection strategy can always meet the needs of different injection stages.

[0010] Optionally, when the injection stage is a filling stage, if the actual injection pressure is greater than the expected injection pressure, the injection pressure of the filling stage in the injection strategy is updated according to the difference between the actual injection pressure and the expected injection pressure; If the actual injection pressure is less than the expected injection pressure, determine whether the actual injection pressure reaches the upper limit of the pressure supply of the injection molding machine; if not, update the injection pressure of the filling stage in the injection strategy according to the difference between the expected injection pressure and the actual injection pressure; if so, determine whether the material of the plastic product is a temperature-sensitive material; If yes, then obtain the fluidity curve of the material of the plastic product, which is used to represent the mapping relationship between the fluidity of the plastic and the temperature; obtain the target fluidity according to the actual injection pressure and the expected injection time of the injection stage in the injection strategy; find the target injection temperature corresponding to the target fluidity in the fluidity curve; update the injection temperature of the filling stage in the injection strategy according to the target injection temperature; If not, the duration of the filling phase in the injection molding strategy is extended according to a first preset ratio.

[0011] By adopting the above technical solution, during the filling stage, the injection molding machine will decide which parameters in the injection molding strategy should be updated based on data such as the material of the plastic product, the expected injection molding pressure and the actual injection molding pressure, so that the injection molding strategy is optimized and the quality of the plastic product can be improved.

[0012] Optionally, according to the injection molding strategy, a first cooling rate of the injection molding machine in the pressure holding stage is obtained; Determine the holding temperature of the plastic material according to the material of the plastic product; Determine whether the temperature difference between the target injection temperature and the holding temperature is greater than a preset difference; If not, the duration of the holding phase in the injection strategy remains unchanged; If so, calculate the ratio of the temperature difference to the first cooling rate to obtain the holding time; extend the holding time of the injection molding strategy according to the holding time; and reduce the injection pressure of the holding time of the injection molding strategy according to the second preset ratio.

[0013] By adopting the above technical solution, the duration of the holding stage and the injection pressure are adjusted, so that the injection molding process in the holding stage can compensate for the impact caused by the optimization of the injection molding strategy in the filling stage, and the injection molding strategy meets the needs of the holding stage.

[0014] Optionally, according to the injection molding strategy, a second cooling rate of the injection molding machine in the cooling stage is obtained; According to the relevant information, the maximum cooling rate of the plastic product in the cooling stage and the critical cooling temperature of the plastic product are obtained, and the maximum cooling rate is greater than the second cooling rate; According to the second cooling rate, the maximum cooling rate and the critical cooling temperature, the cooling stage in the injection molding strategy is updated so that the plastic product is cooled at the second cooling rate at the beginning of the cooling stage, and is cooled at the maximum cooling rate when the temperature of the plastic product reaches the critical cooling temperature.

[0015] By adopting the above technical solution, the cooling rate in the cooling stage is adjusted so that the injection molding process in the cooling stage can compensate for the impact caused by the optimization of the injection molding strategy in the filling stage, so that the injection molding strategy meets the needs of the cooling stage.

[0016] Optionally, when the injection stage is a pressure holding stage, calculating the injection pressure difference between the actual injection pressure and the expected injection pressure; Count the number of injection pressure differences that are greater than a preset pressure difference; Determine whether the difference quantity is greater than a preset quantity; If yes, determining a third preset ratio according to the difference amount; increasing the injection pressure in the pressure holding stage of the injection strategy according to the third preset ratio; If not, the injection molding strategy remains unchanged.

[0017] By adopting the above technical solution, when the injection molding stage is the holding stage, the injection molding pressure in the holding stage will be increased when the difference number is greater than the preset number to ensure that various parameters in the holding stage meet the requirements, thereby improving the quality of plastic products.

[0018] Optionally, obtaining the temperature distribution of the plastic product; Calculate the average temperature of plastic products based on temperature distribution; Obtain the area on the plastic product where the temperature is lower than the average temperature, and obtain the low temperature area; For low temperature areas, reduce the cooling rate during the holding phase of the injection molding strategy.

[0019] By adopting the above technical solution, the cooling rate of the low-temperature area is changed during the pressure holding stage, so that the low-temperature area can be cooled at a slower rate, which can balance the overall temperature of the plastic product, solve the uneven pressure distribution caused by uneven temperature distribution, and improve the quality of the plastic product.

[0020] In a second aspect, the present application provides an injection molding control system for an injection molding machine, which adopts the following technical solution: An injection molding control system for an injection molding machine, comprising: An acquisition module, used to acquire relevant information, actual injection pressure, timestamp information, pressure supply upper limit, fluidity curve, first preset ratio, second preset ratio, first cooling rate, second cooling rate, preset quantity and temperature distribution; A memory for storing a program of the injection molding control method of the injection molding machine according to any one of the above items; The program in the processor memory can be loaded and executed by the processor to implement any of the above injection molding control methods for the injection molding machine.

[0021] By adopting the above technical solution, the injection molding strategy is updated and executed according to the actual injection molding pressure of the injection molding machine and the injection molding stage corresponding to the actual injection molding pressure. This method allows the injection molding strategy to be adjusted according to the requirements of different injection molding stages, so that the injection molding strategy always meets the requirements and can effectively improve the quality of plastic products.

[0022] In a third aspect, the present application provides an injection molding machine, which adopts the following technical solution: An injection molding machine comprises a memory and a processor, wherein the memory stores a computer program which can be loaded by the processor and execute any one of the above methods.

[0023] By adopting the above technical solution, the injection molding strategy is updated and executed according to the actual injection molding pressure of the injection molding machine and the injection molding stage corresponding to the actual injection molding pressure. This method allows the injection molding strategy to be adjusted according to the requirements of different injection molding stages, so that the injection molding strategy always meets the requirements and can effectively improve the quality of plastic products.

[0024] In a fourth aspect, the present application provides a computer storage medium capable of storing a corresponding program, which is convenient for optimizing the injection molding strategy of an injection molding machine and improving the quality of plastic products, and adopts the following technical solution: A computer-readable storage medium stores a computer program that can be loaded by a processor and execute any of the above-mentioned injection molding control methods for injection molding machines.

[0025] By adopting the above technical solution, the injection molding strategy is updated and executed according to the actual injection molding pressure of the injection molding machine and the injection molding stage corresponding to the actual injection molding pressure. This method allows the injection molding strategy to be adjusted according to the requirements of different injection molding stages, so that the injection molding strategy always meets the requirements and can effectively improve the quality of plastic products.

[0026] In summary, the present application includes at least one of the following beneficial technical effects: 1. Update and execute the injection molding strategy according to the actual injection molding pressure of the injection molding machine and the injection molding stage corresponding to the actual injection molding pressure. This method allows the injection molding strategy to be adjusted according to the requirements of different injection molding stages, so that the injection molding strategy always meets the requirements and can effectively improve the quality of plastic products; 2. During the filling stage, the injection molding machine will decide which parameters in the injection molding strategy should be updated based on the material of the plastic product, the expected injection molding pressure, the actual injection molding pressure and other data, so that the injection molding strategy can be optimized and the quality of the plastic product can be improved; 3. When the injection molding stage is the holding stage, the injection pressure of the holding stage will be increased when the difference number is greater than the preset number to ensure that various parameters in the holding stage meet the requirements, thereby improving the quality of the plastic product. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a flow chart of an injection molding control method of an injection molding machine disclosed in an embodiment of the present application.

[0028] Figure 2 It is a flow chart of an injection molding control method of an injection molding machine disclosed in an embodiment of the present application.

[0029] Figure 3 It is a flow chart of an injection molding control method of an injection molding machine disclosed in an embodiment of the present application.

[0030] Figure 4 It is a flow chart of an injection molding control method of an injection molding machine disclosed in an embodiment of the present application.

[0031] Figure 5 It is a flow chart of an injection molding control method of an injection molding machine disclosed in an embodiment of the present application.

[0032] Figure 6 It is a flow chart of an injection molding control method of an injection molding machine disclosed in an embodiment of the present application.

[0033] Figure 7 It is a flow chart of an injection molding control method of an injection molding machine disclosed in an embodiment of the present application.

[0034] Figure 8 It is a schematic diagram of an injection molding control system of an injection molding machine disclosed in an embodiment of the present application. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of this application more clear, the following Figure 1-8 It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0036] The present application embodiment discloses an injection molding control method of an injection molding machine. Figure 1 , the method comprising: Step S11: acquiring an injection molding strategy corresponding to the relevant information of the plastic product, wherein the relevant information includes the material, structure and size of the plastic product.

[0037] Injection molding strategy refers to the way in which the injection molding machine controls the injection molding parameters when manufacturing plastic products. Injection molding parameters include injection molding pressure, injection molding temperature, injection molding time, cooling rate, etc. Injection molding pressure refers to the pressure of the molten plastic extruded by the injection molding machine, injection molding temperature refers to the temperature of the molten plastic extruded by the nozzle of the injection molding machine, and injection molding time refers to the relative time in a single injection molding process. For example, when the injection molding time is 5 seconds, the injection molding machine needs to provide an injection molding pressure of 50Mpa and control the injection molding temperature of the molten plastic at 180℃.

[0038] Exemplarily, a corresponding relationship between relevant information and a preset injection molding strategy is stored in a memory of the injection molding machine; the injection molding strategy corresponding to the relevant information is searched according to the corresponding relationship.

[0039] Exemplarily, the injection molding machine searches for the injection molding strategy in the historical operation records according to the relevant information.

[0040] Step S12: while the injection molding machine is operating according to the injection molding strategy, obtaining the actual injection molding pressure of the injection molding machine.

[0041] The actual injection pressure refers to the pressure of the molten plastic extruded by the nozzle of the injection molding machine during the actual working process of the injection molding machine. In some embodiments, a pressure sensor is provided on the nozzle of the injection molding machine, and the pressure sensor can detect the actual injection pressure.

[0042] Step S13: updating and executing the injection strategy according to the actual injection pressure and the injection stage corresponding to the actual injection pressure, the injection stage including the filling stage, the pressure holding stage and the cooling stage.

[0043] The filling stage refers to when the plastic is injected into the mold. A higher injection pressure is required to ensure that the molten plastic can completely fill all the details of the mold.

[0044] The holding stage means that after filling is completed, the injection pressure will be maintained at a higher level to compensate for the shrinkage of the plastic during the cooling process and ensure the stability of the product size.

[0045] The cooling stage refers to when the plastic cools and solidifies, the injection pressure will be gradually reduced until the injection process is completed.

[0046] In this embodiment, the injection molding strategy is divided according to the injection molding stage. For example, in the filling stage, the injection molding machine fills the molten plastic into the mold at an injection pressure of 50 MPa, and the temperature of the molten plastic is 170°C; the injection molding machine maintains the injection pressure at 40 MPa in the pressure holding stage; the injection molding machine reduces the injection pressure over time in the cooling stage, and releases the plastic product when the plastic product solidifies.

[0047] In summary, the injection molding strategy is updated and executed according to the actual injection molding pressure of the injection molding machine and the injection molding stage corresponding to the actual injection molding pressure. This method allows the injection molding strategy to be adjusted according to the requirements of different injection molding stages, so that the injection molding strategy always meets the requirements and can effectively improve the quality of plastic products.

[0048] In the following embodiments, Figure 1 In step S13 of the embodiment shown, the embodiment determines whether the injection strategy needs to be changed by judging whether the actual injection pressure is consistent with the expected injection pressure. The embodiment of the present application discloses an injection molding control method for an injection molding machine. Figure 2 , the method comprising: Step S201: Obtaining timestamp information corresponding to the actual injection pressure.

[0049] The timestamp information refers to the time when the actual injection pressure is read. Furthermore, the timestamp information is divided according to a single injection process. For example, each injection takes 35 seconds, and the timestamp information will record at which second of the 35 seconds the actual injection pressure is read.

[0050] Step S202: according to the timestamp information, searching the injection strategy for the expected injection pressure corresponding to the timestamp information.

[0051] The desired injection pressure refers to the injection pressure recorded on the injection strategy.

[0052] Optionally, the injection strategy records the injection pressure and injection time, so the expected injection pressure corresponding to the timestamp information can be determined by the injection time.

[0053] Step S203: Determine whether the actual injection pressure is consistent with the expected injection pressure.

[0054] If the actual injection pressure is consistent with the expected injection pressure, step S204 is executed; If the actual injection pressure is inconsistent with the expected injection pressure, step S205 is executed.

[0055] Step S204: If yes, the injection molding strategy is kept unchanged and executed.

[0056] When the actual injection pressure is consistent with the expected injection pressure, it indicates that the injection molding machine is executing the preset injection molding strategy, the working state of the injection molding machine is normal, and there is no need to update the injection molding strategy of the injection molding machine.

[0057] Step S205: If not, determine the injection molding stage according to the timestamp information.

[0058] When the actual injection pressure is inconsistent with the expected injection pressure, it means that the injection molding machine is not executing the preset injection molding strategy at this time, and the working state of the injection molding machine is abnormal. The injection molding strategy of the injection molding machine needs to be updated to ensure the quality of the plastic product.

[0059] Furthermore, since the injection molding strategy is divided according to the injection molding stages, the injection molding stage corresponding to the timestamp information can be determined through the injection molding strategy.

[0060] Step S206: updating the injection strategy according to the actual injection pressure and the injection stage, and executing the updated injection strategy.

[0061] In this application, it is necessary to update the injection molding strategy in different ways according to different injection molding stages to ensure the quality of the plastic products and to shorten the processing time of each plastic product as much as possible. The specific implementation methods can be referred to in the subsequent embodiments, which will not be described here.

[0062] In other aspects of this embodiment, for different injection molding stages, a current long vector is generated according to various parameters in the current injection molding stage. The current long vector includes injection molding parameters, environmental parameters of the environment in which the injection molding machine is located, and the current injection molding strategy of the injection molding machine. The injection molding parameters include but are not limited to at least one of injection molding pressure, injection molding temperature, and plastic flow rate. The environmental parameters include but are not limited to at least one of ambient temperature, ambient humidity, and time. According to the historical records of the injection molding machine in different scenarios, several historical long vectors are counted and generated, and each historical long vector corresponds to a scenario. According to the scenario corresponding to the current long vector, the corresponding historical long vector is determined, and the similarity between the current long vector and the historical long vector is calculated. With the similarity as feedback, the working state of the injection molding machine is adjusted to make the current long vector close to the aforementioned historical long vector.

[0063] In summary, the injection strategy is determined by judging whether the actual injection pressure is consistent with the expected injection pressure, so that the injection strategy can always meet the needs of different injection stages.

[0064] In the following embodiments, when the injection molding stage is a filling stage, more consideration needs to be given to how to fully fill the molten plastic into the mold so that it fills all the details of the mold. To this end, the embodiment of the present application discloses an injection molding control method of an injection molding machine. Figure 3 , the method comprising: Step S301: when the injection stage is the filling stage, if the actual injection pressure is greater than the expected injection pressure, the injection pressure of the filling stage in the injection strategy is updated according to the difference between the actual injection pressure and the expected injection pressure.

[0065] For example, when the actual injection pressure is greater than the expected injection pressure, the injection pressure of the filling stage in the injection strategy can be reduced directly according to the difference between the actual injection pressure and the expected injection pressure. Furthermore, after the injection molding machine executes the updated injection molding strategy, the actual injection pressure can be detected to determine again whether the actual injection pressure is the same as the expected injection pressure; if they are the same, the process of this embodiment is terminated; if they are different, the injection molding is suspended and an error signal is sent to the user terminal, which is used to indicate that there is a problem with the injection pressure control system of the injection molding machine.

[0066] Step S302: If the actual injection pressure is less than the expected injection pressure, it is determined whether the actual injection pressure reaches the upper limit of the pressure supply of the injection molding machine.

[0067] If the actual injection pressure reaches the upper limit of the pressure energy supply of the injection molding machine, execute steps S304 to S309; If the actual injection pressure reaches the upper limit of the pressure energy supply of the injection molding machine, step S303 is executed.

[0068] The upper limit of pressure function refers to the maximum injection pressure that the injection molding machine can provide during actual working process.

[0069] When the actual injection pressure is greater than the expected injection pressure, it is also necessary to consider whether the actual injection pressure has reached the upper limit of the pressure function that the injection molding machine can provide. In actual production scenarios, due to various reasons such as aging and wear of the injection molding machine and damage to components, the output power of the injection molding machine will be caused to decrease, causing the upper limit of the pressure energy supply of the injection molding machine to decrease. Therefore, it is necessary to first determine whether the actual injection pressure has reached the upper limit of the pressure energy supply of the injection molding machine to determine whether the actual injection pressure of the injection molding machine can be further increased.

[0070] Step S303: If not, then update the injection pressure of the filling phase in the injection strategy according to the difference between the expected injection pressure and the actual injection pressure.

[0071] Exemplarily, the difference between the expected injection pressure and the actual injection pressure is increased, and the injection pressure of the filling stage in the injection strategy is updated. This step requires that the expected injection pressure is less than the upper limit of the pressure supply of the injection molding machine.

[0072] In another case, the expected injection pressure is greater than the upper limit of the pressure supply of the injection molding machine, and at this time, the injection molding machine still cannot provide sufficient injection pressure. Then, step S304 will be executed at this time.

[0073] Step S304: If yes, determine whether the material of the plastic product is a temperature sensitive material.

[0074] If the material of the plastic product is a temperature-sensitive material, then execute steps S305 to S308; If the material of the plastic product is not a temperature-sensitive material, step S309 is executed.

[0075] Temperature sensitive materials refer to plastic materials whose fluidity changes by more than a preset value under unit temperature change. Exemplarily, temperature sensitive materials include polyethylene (PE), polypropylene (PP), polycarbonate (PC), polyamide (PA), polyoxymethylene (POM) and polyphenylene sulfide (PPS).

[0076] Step S305: If yes, then obtain the fluidity curve of the material of the plastic product, where the fluidity curve is used to represent the mapping relationship between the fluidity of the plastic and the temperature.

[0077] Optionally, the fluidity is represented by melt flow rate (MFR) or melt flow index (MFI). Taking MFR as an example, the fluidity curve is a curve with temperature as the horizontal axis and MFR value as the vertical axis.

[0078] Optionally, fluidity can also be expressed by viscosity. In this case, the fluidity curve is a curve with temperature as the horizontal axis and viscosity value as the vertical axis.

[0079] Step S306: Obtain target fluidity according to the actual injection pressure and the expected injection duration of the injection stage in the injection strategy.

[0080] The expected injection time refers to the time required to fill the mold in the injection molding strategy. On the other hand, the expected injection time can also refer to the total time of the filling phase.

[0081] Exemplarily, taking fluidity as MFI as an example, the remaining injection time is obtained based on the difference between the expected injection time and the actual injection time; the injection speed is calculated based on the actual injection pressure; the volume of plastic in the mold is calculated based on the injection speed and the actual injection time; the difference between the total volume of the mold and the volume of the plastic is calculated to obtain the remaining volume of the mold; and the target fluidity is obtained based on the ratio of the remaining volume to the remaining injection time.

[0082] Step S307: searching the fluidity curve for a target injection temperature corresponding to the target fluidity.

[0083] Since it has been determined that the plastic product uses temperature-sensitive materials, the present embodiment changes the fluidity of the molten plastic by changing the injection temperature to compensate for the problem caused by insufficient injection pressure provided by the injection molding machine. In this way, the mold can be filled with molten plastic without extending the length of the filling phase.

[0084] Step S308: updating the injection temperature of the filling phase in the injection strategy according to the target injection temperature.

[0085] Exemplarily, the injection temperature of the filling stage in the injection strategy is updated to the target injection temperature. For example, a heating device is provided on the nozzle of the injection molding machine, and the injection temperature of the molten plastic extruded by the nozzle is changed by changing the temperature of the heating device.

[0086] Step S309: If not, then extend the duration of the filling phase in the injection molding strategy according to a first preset ratio.

[0087] If the material of the plastic product is not temperature-sensitive, the injection molding machine will compensate for the problem of insufficient injection pressure provided by the injection molding machine by extending the duration of the filling phase so that the molten plastic can fill the mold.

[0088] The first preset ratio is a constant. For example, the first preset ratio is 20%. If the duration of the filling phase in the original injection molding strategy is 20 seconds, then after being extended according to the first preset ratio, the duration of the filling phase becomes 24 seconds.

[0089] In other aspects of this embodiment, a preset conversion formula is called to process the mold temperature data to obtain an ideal injection pressure; a difference between the actual injection pressure and the ideal injection pressure is compared to determine whether it is less than a preset difference threshold; if not, the injection pressure of the injection molding machine in the next filling stage is adjusted according to the difference between the actual injection pressure and the ideal injection pressure; Among them, the preset conversion formula is: F represents the ideal injection pressure, α is the preset conversion coefficient, T k is the mold temperature at point k on the injection mold, L k is the distance from the kth point on the injection mold to the injection port, and S is the surface area of ​​the injection mold.

[0090] In summary, during the filling stage, the injection molding machine will decide which parameters in the injection molding strategy should be updated based on data such as the material of the plastic product, the expected injection molding pressure and the actual injection molding pressure, so that the injection molding strategy can be optimized and the quality of the plastic product can be improved.

[0091] In the following example, if Figure 3In the embodiment shown, the problem of insufficient injection pressure provided by the injection molding machine is solved by increasing the temperature, which will cause the temperature of the molten plastic to be too high, causing the volume of the molten plastic to expand, and affecting the compensation for plastic shrinkage during the pressure holding stage. To solve the above problems, the embodiment of the present application discloses an injection molding control method for an injection molding machine. Figure 4 , the method comprising: Step S401: according to the injection molding strategy, obtaining the first cooling rate of the injection molding machine in the pressure holding stage.

[0092] The first cooling rate refers to the temperature drop of the plastic per second during the holding stage in the injection molding strategy.

[0093] Step S402: Determine the holding temperature of the plastic material according to the material of the plastic product.

[0094] The holding temperature refers to the temperature required for the plastic when the injection molding machine enters the cooling stage from the holding stage. Furthermore, the holding temperature is related to the curing temperature of the plastic, and the holding temperature is greater than the curing temperature. For example, the difference between the holding temperature and the curing temperature is a constant. If the curing temperature is 120°C, then the holding temperature can be 130°C. For example, the curing temperature is amplified by a preset ratio to obtain the holding temperature. If the curing temperature is 120°C, then the curing temperature is amplified by 10%, and the holding temperature is 132°C.

[0095] Step S403: determining whether the temperature difference between the target injection temperature and the holding temperature is greater than a preset difference.

[0096] If the temperature difference between the target injection temperature and the holding temperature is greater than the preset difference, executing steps S405 to S407; If the temperature difference between the target injection temperature and the holding temperature is not greater than the preset difference, step S404 is executed.

[0097] The preset difference is a constant, and illustratively, the preset difference is 20°C.

[0098] Step S404: If not, the duration of the pressure holding phase in the injection molding strategy is maintained unchanged.

[0099] If the temperature difference between the target injection temperature and the holding temperature is not greater than the preset difference, it means that the time required to cool the target injection temperature to the holding temperature is within the tolerable error range, and there is no need to change the duration of the holding stage in the injection strategy.

[0100] Step S405: If yes, the ratio of the temperature difference to the first cooling rate is calculated to obtain the holding time.

[0101] If the temperature difference between the target injection temperature and the holding temperature is greater than the preset difference, it means that the time required to cool the target injection temperature to the holding temperature has exceeded the error range, and the duration of the holding stage in the injection molding strategy is extended. The molten plastic in this embodiment is heated to the target injection temperature and then squeezed into the mold. If the duration of the holding stage is not changed, the temperature of the plastic entering the cooling stage will be greater than the holding temperature. Affected by the thermal expansion and contraction characteristics of the plastic, the plastic will further shrink after it is cooled to the holding temperature, resulting in the size of the produced plastic product being smaller than the standard size of the plastic product, affecting the quality of the plastic product. Therefore, this embodiment avoids the above situation by increasing the duration of the holding stage.

[0102] Step S406: extending the duration of the pressure holding phase in the injection molding strategy according to the pressure holding duration.

[0103] Exemplarily, the duration of the holding pressure phase in the injection molding strategy is extended to the aforementioned holding pressure duration.

[0104] Step S407: reducing the injection pressure in the pressure holding stage of the injection strategy according to a second preset ratio.

[0105] Because the material of plastic products is temperature-sensitive and the temperature of the plastic is relatively high, the molten plastic has better fluidity and can enter the mold through lower injection pressure to fill the details in the mold.

[0106] In actual production scenarios, the injection pressure in the holding stage is usually lower than that in the filling stage, so the injection molding machine can usually generate the injection pressure required in the holding stage.

[0107] Furthermore, if after the injection pressure of the pressure holding stage in the injection molding strategy is increased according to the second preset ratio, the injection pressure is less than the upper limit of the pressure energy supply of the injection molding machine, the injection pressure of the pressure holding stage in the injection molding strategy is set to the upper limit of the pressure energy supply, and based on the difference between the increased injection pressure and the upper limit of the pressure energy supply, the duration of the pressure holding stage in the injection molding strategy is extended again.

[0108] For example, if the difference between the increased injection pressure and the upper limit of the pressure energy supply is 1 MPa, the duration of the holding phase in the injection strategy is further extended by t=kp, wherein p is the aforementioned difference in MPa; and k is a constant, for example, k=1.5.

[0109] The second preset ratio is a constant. For example, the second preset ratio is 20%. If the injection pressure in the holding stage in the original injection strategy is 40 MPa, then after being reduced according to the second preset ratio, the injection pressure in the holding stage becomes 32 MPa.

[0110] In summary, the duration of the holding phase and the injection pressure are adjusted so that the injection molding process in the holding phase can compensate for the impact caused by the optimization of the injection molding strategy in the filling phase, and the injection molding strategy meets the needs of the holding phase.

[0111] In the following examples, Figure 4 In the embodiment shown, after extending the duration of the pressure holding phase in the injection molding strategy, the duration of the cooling phase can be shortened to ensure that the duration of the entire injection molding phase is within the error range. Therefore, the embodiment of the present application discloses an injection molding control method for an injection molding machine. Figure 5 , the method comprising: Step S501: according to the injection molding strategy, obtaining a second cooling rate of the injection molding machine in the cooling stage.

[0112] The second cooling rate refers to the temperature drop of the plastic per second during the cooling phase of the injection molding strategy.

[0113] Optionally, the injection molding strategy records the injection molding stage and the cooling rate, so the second cooling rate of the injection molding machine in the cooling stage can be obtained through the injection molding strategy.

[0114] Step S502: According to relevant information, the maximum cooling rate of the plastic product in the cooling stage and the critical cooling temperature of the plastic product are obtained, and the maximum cooling rate is greater than the second cooling rate.

[0115] The maximum cooling rate refers to the maximum rate that a plastic product can accept for cooling. When the cooling rate of a plastic product is greater than the maximum cooling rate, stress and warping will be generated inside the plastic product, causing the size of the plastic product to fail to meet the standard or the structure to be damaged. For example, the maximum cooling rate is an empirical value.

[0116] The structural strength of the plastic product at the temporary cooling temperature is greater than the preset strength. Since the plastic in the mold changes from a molten state to a solid state, the structure of the plastic product will improve as the temperature decreases during this process. Among them, the structural strength is at least one of tensile strength, compressive strength, bending strength, shear strength, fatigue strength, stiffness and toughness.

[0117] Step S503: According to the second cooling rate, the maximum cooling rate and the critical cooling temperature, the cooling stage in the injection molding strategy is updated so that the plastic product is cooled at the second cooling rate at the beginning of the cooling stage, and is cooled at the maximum cooling rate when the temperature of the plastic product reaches the critical cooling temperature.

[0118] In this step, the cooling stage is divided into two stages: the first stage is to cool the plastic to the critical cooling temperature at the second cooling rate, and the second stage is to cool the plastic at the maximum cooling rate. In the first stage, cooling the plastic at the second cooling rate can ensure that the plastic product will not be broken or damaged, thereby ensuring the quality of the plastic product. In the second stage, cooling the plastic at the maximum cooling rate can shorten the duration of the cooling stage, and since the plastic itself has a certain structural strength in the second stage, cooling at the maximum cooling rate has little effect on the structure and size of the plastic product.

[0119] In some other embodiments, when the temperature of the plastic product does not reach the critical cooling temperature, the temperature distribution of the plastic product is obtained; when the temperature distribution does not meet the preset temperature distribution, the temperature abnormal area in the plastic product is obtained; the temperature abnormal area is regionally heated; when the temperature of the temperature abnormal area reaches the preset temperature, the plastic product in the temperature abnormal area is recycled into the nozzle of the injection molding machine; and the injection molding strategy is updated according to the position and temperature distribution of the temperature abnormal area. For example, when the temperature in the temperature abnormal area is too low, the cooling rate of the cooling stage can be reduced, and the duration of the pressure holding stage can be extended; when the temperature in the temperature abnormal area is too high, the cooling rate of the cooling stage can be increased, and the duration of the pressure holding stage can be extended.

[0120] In some other embodiments, during the cooling stage, the ambient temperature of the injection molding machine is obtained; it is determined whether the ambient temperature is less than a preset temperature threshold; if not, the injection molding strategy is maintained unchanged; if so, the cooling rate of the cooling stage in the injection molding strategy is reduced according to the difference between the ambient temperature and the preset temperature threshold; the extension time of the cooling stage in the injection molding strategy is calculated according to the updated cooling rate; and the duration of the holding stage in the injection molding strategy is shortened according to the extension time.

[0121] In some other embodiments, during the cooling stage, the ambient temperature of the injection molding machine is obtained; it is determined whether the ambient temperature is less than a preset temperature threshold; if not, the injection molding strategy is maintained unchanged; if so, the cooling rate of the cooling stage in the injection molding strategy is reduced according to the difference between the ambient temperature and the preset temperature threshold; the extension time of the cooling stage in the injection molding strategy is calculated according to the updated cooling rate; and the duration of the holding stage in the injection molding strategy is shortened according to the extension time.

[0122] In summary, the cooling rate in the cooling stage is adjusted so that the injection molding process in the cooling stage can compensate for the impact caused by the optimization of the injection molding strategy in the filling stage, so that the injection molding strategy meets the needs of the cooling stage.

[0123] In the following embodiments, when the injection molding stage is a pressure holding stage, it is necessary to consider that the plastic will shrink during the cooling process, so it is necessary to continue to maintain the injection molding pressure at a high level to ensure the structural and dimensional stability of the plastic product. Therefore, how to maintain the injection molding pressure stable during the pressure holding stage is the main consideration of this embodiment. Therefore, the embodiment of the present application discloses an injection molding control method for an injection molding machine. Figure 6 , the method comprising: Step S601: when the injection stage is a pressure holding stage, calculating the injection pressure difference between the actual injection pressure and the expected injection pressure.

[0124] In this embodiment, the desired injection pressure refers to the injection pressure in the holding pressure stage of the injection strategy.

[0125] Optionally, the mold is composed of a plurality of sub-molds, each of which is provided with at least one pressure sensor. For example, the mold can produce 10 plastic products at one time, and the mold has 10 sub-molds, each of which is used to produce 1 plastic product.

[0126] Optionally, a plurality of pressure sensors are provided on the mold, and the actual injection pressure is obtained through the pressure sensors.

[0127] Step S602: Counting the number of injection pressure difference values ​​that are greater than a preset pressure difference value.

[0128] The preset pressure difference is a preset constant, for example, the preset pressure difference is 1.2 MPa.

[0129] Step S603: Determine whether the difference quantity is greater than a preset quantity.

[0130] If the number of differences is greater than the preset number, executing steps S604 to S605; If the number of differences is not greater than the preset number, step S606 is executed.

[0131] The preset number is a preset constant, for example, the preset number is 5.

[0132] Step S604: If yes, determine a third preset ratio according to the difference quantity.

[0133] If the number of differences is greater than the preset number, it means that the injection molding strategy actually adopted by the injection molding machine has a large deviation from the preset injection molding strategy, so the executed injection molding strategy needs to be updated.

[0134] Exemplarily, the memory of the injection molding machine stores a correspondence between the difference number and the third preset ratio, and the injection molding machine can directly search for the third preset ratio in the correspondence according to the difference number. For example, when the difference number is 6, the third preset ratio is 10%; when the difference number is 7, the third preset ratio is 12.

[0135] Step S605: increasing the injection pressure in the pressure holding phase of the injection strategy according to a third preset ratio.

[0136] In the holding pressure stage, if the actual injection pressure in multiple places is inconsistent with the expected injection pressure, it means that the injection molding machine has pressure fluctuations in the holding pressure stage. In this case, it is necessary to consider increasing the injection pressure to ensure the stability of the injection pressure. On the other hand, if the injection pressure is reduced, it may lead to insufficient holding pressure, which in turn affects the quality of the plastic product.

[0137] It should be noted that this step at most increases the injection pressure to the upper limit of the holding pressure. The upper limit of the holding pressure refers to the upper limit of the pressure that the mold and plastic material can withstand during the holding stage, and the upper limit of the holding pressure is an empirical value.

[0138] Step S606: If not, the injection molding strategy is maintained unchanged.

[0139] If the number of differences is not greater than the preset number, it means that the injection molding strategy actually adopted by the injection molding machine does not have a large deviation from the preset injection molding strategy, so there is no need to update the executed injection molding strategy.

[0140] In summary, when the injection molding stage is the holding stage, the injection molding pressure in the holding stage will be increased when the difference number is greater than the preset number to ensure that various parameters in the holding stage meet the requirements, which can improve the quality of plastic products.

[0141] In the following examples, Figure 6 In the embodiment shown, when the injection molding machine experiences injection pressure fluctuations during the pressure holding stage, the flow of the plastic can be promoted by changing the temperature distribution of the plastic in the mold to alleviate the impact of the pressure fluctuations. Therefore, the embodiment of the present application discloses an injection molding control method for an injection molding machine. Figure 7 , the method comprising: Step S701: Obtaining the temperature distribution of the plastic product.

[0142] Temperature distribution is used to represent the temperature at different locations on the plastic product within the mold.

[0143] Optionally, the mold is composed of a plurality of sub-molds, each of which is provided with at least one temperature sensor, and the mold can generate a plurality of plastic products in a single injection molding. For example, the mold can produce 10 plastic products at one time, and the mold has 10 sub-molds, each of which is used to produce 1 plastic product.

[0144] Step S702: Calculate the average temperature of the plastic product according to the temperature distribution.

[0145] Exemplarily, the sum of the temperatures at various locations is calculated based on the temperature distribution; the ratio of the sum of the temperatures to the number of temperatures is calculated to obtain the average temperature.

[0146] Step S703: Acquire the area on the plastic product where the temperature is lower than the average temperature to obtain the low temperature area.

[0147] The fluidity of plastic in the low-temperature area is worse than that in other areas. Therefore, this step requires first determining the location of the low-temperature area and then treating the low-temperature area separately.

[0148] Step S704: for the low temperature region, reducing the cooling rate of the pressure holding stage in the injection molding strategy.

[0149] This step will reduce the cooling rate of the low temperature area, so that the temperature of the plastic in each part of the mold tends to be the same, which can solve the uneven pressure distribution caused by uneven temperature distribution. In addition, when the low temperature area is cooled at a slower cooling rate, the plastic in the low temperature area can be maintained at a higher temperature for a certain period of time, which promotes the flow of the plastic in the low temperature area.

[0150] For example, the injection molding machine can control the cooling rate of each sub-mold in the mold individually. For example, if sub-mold A is a low temperature area, the cooling rate of sub-mold A can be indirectly changed by changing the rate / temperature of the coolant passing into sub-mold A.

[0151] In summary, changing the cooling rate of the low-temperature area during the pressure holding stage so that the low-temperature area can be cooled at a slower rate can balance the overall temperature of the plastic product, solve the uneven pressure distribution caused by uneven temperature distribution, and improve the quality of the plastic product.

[0152] Based on the same inventive concept, the embodiment of the present application provides an injection molding control system of an injection molding machine, comprising: An acquisition module 801 is used to acquire relevant information, actual injection pressure, timestamp information, pressure supply upper limit, fluidity curve, first preset ratio, second preset ratio, first cooling rate, second cooling rate, preset quantity and temperature distribution; a memory 802 is used to store a program of the injection molding control method of any one of the above injection molding machines; Processor 803, the program in the memory can be loaded and executed by the processor to implement any of the above injection molding control methods for the injection molding machine.

[0153] In summary, the injection molding strategy is updated and executed according to the actual injection molding pressure of the injection molding machine and the injection molding stage corresponding to the actual injection molding pressure. This method allows the injection molding strategy to be adjusted according to the requirements of different injection molding stages, so that the injection molding strategy always meets the requirements and can effectively improve the quality of plastic products.

[0154] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. The specific working process of the system, device and unit described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0155] An embodiment of the present application provides a computer-readable storage medium storing a computer program that can be loaded by a processor and executed by an injection molding control method of an injection molding machine.

[0156] Computer storage media include, for example, various media that can store program codes, such as USB flash drives, mobile hard disks, read-only memories (ROM), random access memories (RAM), magnetic disks or optical disks.

[0157] Based on the same inventive concept, an embodiment of the present application provides an intelligent terminal, including a memory and a processor, wherein the memory stores a computer program that can be loaded by the processor and execute an injection molding control method of an injection molding machine.

[0158] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. The specific working process of the system, device and unit described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0159] The above are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. Any feature disclosed in this specification (including the abstract and drawings), unless otherwise stated, can be replaced by other equivalent or alternative features with similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

Claims

1. An injection molding control method for an injection molding machine, characterized in that: The method comprises: According to the relevant information of the plastic product, an injection molding strategy corresponding to the relevant information is acquired, wherein the relevant information includes the material, structure and size of the plastic product; When the injection molding machine operates according to the injection molding strategy, obtaining the actual injection molding pressure of the injection molding machine; The injection strategy is updated and executed according to the actual injection pressure and the injection stage corresponding to the actual injection pressure, wherein the injection stage includes a filling stage, a pressure holding stage and a cooling stage.

2. The injection molding control method of an injection molding machine according to claim 1, characterized in that: The updating and executing of the injection strategy according to the actual injection pressure and the injection stage corresponding to the actual injection pressure includes: Obtaining timestamp information corresponding to the actual injection pressure; According to the timestamp information, searching the injection strategy for an expected injection pressure corresponding to the timestamp information; Determining whether the actual injection pressure is consistent with the expected injection pressure; If yes, keep the injection molding strategy unchanged and execute the injection molding strategy; If not, determining the injection molding stage according to the timestamp information; updating the injection molding strategy according to the actual injection molding pressure and the injection molding stage, and executing the updated injection molding strategy.

3. The injection molding control method of an injection molding machine according to claim 2, characterized in that: The updating of the injection strategy according to the injection stage and the actual injection pressure comprises: In the case where the injection molding stage is a filling stage, if the actual injection molding pressure is greater than the expected injection molding pressure, the injection molding pressure of the filling stage in the injection molding strategy is updated according to the difference between the actual injection molding pressure and the expected injection molding pressure; if the actual injection molding pressure is less than the expected injection molding pressure, it is determined whether the actual injection molding pressure reaches the upper limit of the pressure energy supply of the injection molding machine; If not, updating the injection pressure of the filling phase in the injection strategy according to the difference between the expected injection pressure and the actual injection pressure; If yes, determine whether the material of the plastic product is a temperature-sensitive material; If yes, then obtain the fluidity curve of the material of the plastic product, the fluidity curve being used to represent the mapping relationship between the fluidity of the plastic and the temperature; obtain the target fluidity according to the actual injection pressure and the expected injection time of the injection stage in the injection strategy; search the target injection temperature corresponding to the target fluidity in the fluidity curve; and update the injection temperature of the filling stage in the injection strategy according to the target injection temperature; If not, the duration of the filling phase in the injection molding strategy is extended according to a first preset ratio.

4. The injection molding control method of an injection molding machine according to claim 3, characterized in that: After the injection temperature in the injection strategy is updated according to the target injection temperature, the method further includes: According to the injection molding strategy, obtaining a first cooling rate of the injection molding machine in a pressure holding stage; Determining the holding temperature of the plastic material according to the material of the plastic product; Determining whether the temperature difference between the target injection temperature and the holding temperature is greater than a preset difference; If not, the duration of the holding pressure phase in the injection molding strategy is maintained unchanged; If so, calculate the ratio of the temperature difference to the first cooling rate to obtain the holding time; extend the holding time of the injection molding strategy according to the holding time; and reduce the injection pressure of the holding time of the injection molding strategy according to a second preset ratio.

5. The injection molding control method of an injection molding machine according to claim 4, characterized in that: After reducing the injection pressure in the pressure holding stage of the injection strategy according to the second preset ratio, the method further includes: According to the injection molding strategy, obtaining a second cooling rate of the injection molding machine in a cooling stage; According to the relevant information, a maximum cooling rate of the plastic product in the cooling stage and a critical cooling temperature of the plastic product are obtained, wherein the maximum cooling rate is greater than the second cooling rate; According to the second cooling rate, the maximum cooling rate and the critical cooling temperature, the cooling stage in the injection molding strategy is updated so that the plastic product is cooled at the second cooling rate at the beginning of the cooling stage, and is cooled at the maximum cooling rate when the temperature of the plastic product reaches the critical cooling temperature.

6. The injection molding control method of an injection molding machine according to claim 5, characterized in that: The method further comprises: When the temperature of the plastic product does not reach the critical cooling temperature, obtaining the temperature distribution of the plastic product; when the temperature distribution does not satisfy the preset temperature distribution, obtaining the temperature abnormal area in the plastic product; Performing regional heating on the abnormal temperature area; When the temperature of the abnormal temperature area reaches a preset temperature, the plastic product in the abnormal temperature area is recovered into the nozzle of the injection molding machine; The injection molding strategy is updated according to the position of the temperature abnormality area and the temperature distribution.

7. The injection molding control method of an injection molding machine according to claim 3, characterized in that: The method further comprises: Call the preset conversion formula to process the mold temperature data and obtain the ideal injection pressure; Comparing whether the difference between the actual injection pressure and the ideal injection pressure is less than a preset difference threshold; If not, adjusting the injection pressure of the injection molding machine in the next filling stage according to the difference between the actual injection pressure and the ideal injection pressure; Wherein, the preset conversion formula is: F represents the ideal injection pressure, α is the preset conversion coefficient, T k is the mold temperature at point k on the injection mold, L k is the distance from the kth point on the injection mold to the injection port, and S is the surface area of ​​the injection mold.

8. An injection molding control system for an injection molding machine, characterized in that: The system comprises: An acquisition module, used to acquire relevant information, actual injection pressure, timestamp information, pressure supply upper limit, fluidity curve, first preset ratio, second preset ratio, first cooling rate, second cooling rate, preset quantity, ambient temperature and temperature distribution; A memory for storing a program of an injection molding control method for an injection molding machine according to any one of claims 1 to 7; The program in the memory can be loaded and executed by the processor to implement the injection molding control method of the injection molding machine as claimed in any one of claims 1 to 7.

9. An injection molding machine, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program which can be loaded by the processor and executes any one of the methods of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: A computer program is stored which can be loaded by a processor and execute the method according to any one of claims 1 to 7.

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