A mold temperature control system and control method based on precision injection molding

Abstract

The present invention discloses a mold temperature control system and a control method based on precision injection molding. The method comprises the following steps: in a heating mode, obtaining a heating temperature rise rate and a current temperature change rate of a mold corresponding to a current injection molding operation stage, and obtaining a compensated temperature rise rate of the mold according to the heating temperature rise rate and the current temperature change rate, and determining a current heating operation performed on the mold according to the current temperature of the mold and the compensated temperature rise rate; in a cooling mode, obtaining a cooling temperature drop rate and a current temperature change rate of the mold corresponding to the current injection molding operation stage, and obtaining a compensated temperature drop rate of the mold according to the cooling temperature drop rate and the current temperature change rate, and determining a current cooling operation performed on the mold according to the current temperature of the mold and the compensated temperature drop rate, and cooling the mold to a target temperature corresponding to the current injection molding operation stage based on the current cooling operation; thereby improving product precision and product quality.

Description

Technical Field

[0001] The present invention relates to the technical field of mold temperature control, and in particular to a mold temperature control system and a control method based on precision injection molding. Background Art

[0002] Mold temperature (mold temperature) refers to the surface temperature of the mold cavity and core. Too high or too low mold temperature will affect the molding cycle and product quality. Therefore, the mold temperature needs to be adjusted during the injection molding process to maintain its temperature within the preset range.

[0003] However, the current method of controlling mold temperature usually relies on manual experience or parameters recommended by relevant equipment manufacturers for adjustment. Since this temperature control method is relatively rough, it is impossible to finely control the mold temperature according to the actual state of the current injection molding operation stage, resulting in the inability to guarantee the accuracy and quality of the injection molded products. Summary of the invention

[0004] In order to solve at least one of the technical problems mentioned above, the present invention provides a mold temperature control system and a control method based on precision injection molding.

[0005] In a first aspect, the present invention provides a mold temperature control method based on precision injection molding, the method comprising the following steps:

[0006] Based on the current injection molding operation stage, determining the temperature control mode of the mold; wherein the temperature control mode includes a heating mode and a cooling mode;

[0007] In the heating mode, the heating temperature rise rate and the current temperature change rate of the mold corresponding to the current injection molding operation stage are obtained, and the compensation temperature rise rate of the mold is obtained according to the heating temperature rise rate and the current temperature change rate, and the current heating operation performed on the mold is determined according to the current temperature of the mold and the compensation temperature rise rate, and the mold is heated to the target temperature corresponding to the current injection molding operation stage based on the current heating operation; wherein the current temperature change rate is the temperature change rate provided to the mold by the current environmental factors during the current injection molding operation stage, and the compensation temperature rise rate is equal to the difference between the heating temperature rise rate and the current temperature change rate;

[0008] In cooling mode, the cooling rate and current temperature change rate of the mold corresponding to the current injection molding operation stage are obtained, and the compensation cooling rate of the mold is obtained according to the cooling rate and the current temperature change rate, and the current cooling operation performed on the mold is determined according to the current temperature of the mold and the compensation cooling rate, and the mold is cooled to the target temperature corresponding to the current injection molding operation stage based on the current cooling operation; wherein the compensation cooling rate is equal to the addition of the cooling rate and the current temperature change rate.

[0009] Preferably, heating the mold to a target temperature corresponding to the current injection molding operation stage based on the current heating operation comprises:

[0010] Obtaining a standard temperature rise slope corresponding to the heating temperature rise rate; wherein the standard temperature rise slope has standard temperature nodes corresponding to each moment, and the standard temperature node is a standard temperature node corresponding to the current temperature of the mold at the current moment;

[0011] Determine whether the current temperature of the mold is at a standard temperature node corresponding to the standard temperature rise slope;

[0012] If so, heating the mold based on the current heating operation;

[0013] If not, based on the difference between the current temperature of the mold and the temperature corresponding to the standard temperature node at the next moment in the standard heating ramp, the current temperature of the mold is controlled to be at the standard temperature node at the next moment in the standard heating ramp, and then the mold is heated based on the current heating operation.

[0014] Preferably, obtaining a standard temperature rise slope corresponding to the heating temperature rise rate comprises:

[0015] Obtaining heat changes of the mold in each injection molding operation stage in a heating mode based on a simulation calculation tool, and drawing a predicted temperature-time curve corresponding to each injection molding operation stage according to the heat changes and the time nodes corresponding to when the current temperature of the mold is obtained at each moment;

[0016] Based on the predicted temperature-time curve, determining the heating time required for the mold in the current injection molding operation stage, wherein the heating time satisfies a preset production cycle;

[0017] According to the predicted temperature-time curve and the heating time, an experimental method is used to obtain a plurality of heat distribution diagrams of the mold in each injection molding operation stage in a heating mode, an actual temperature-time curve obtained based on the plurality of heat distribution diagrams, and a quality evaluation result of the injection molded product formed based on the actual temperature-time curve and the heating time; wherein the quality evaluation result includes dimensional accuracy;

[0018] Based on the dimensional accuracy of the injection molded product, the actual temperature-time curve is optimized. If the dimensional accuracy of the injection molded product after the optimization is not within the allowable error range, the actual temperature-time curve corresponding to the last optimization is determined as the optimal actual temperature-time curve; wherein the duration of the heating time after each optimization is sequentially reduced, and the dimensional accuracy of the injection molded product corresponding to the optimal actual temperature-time curve is within the allowable error range;

[0019] Based on the optimal actual temperature-time curve, the heating temperature rise rate is obtained, and the optimal actual temperature-time curve is used as a standard temperature rise slope corresponding to the heating temperature rise rate;

[0020] According to the heating temperature rise rate and the standard temperature rise slope, the actual heating time and target temperature required for the mold in the current injection molding operation stage are determined, and the corresponding standard temperature node is obtained based on the time node.

[0021] Preferably, the current temperature of the mold includes:

[0022] Acquire a fixed mold temperature of the mold, a movable mold temperature of the mold, and a first temperature difference between the fixed mold temperature and the movable mold temperature;

[0023] If the first temperature difference is not equal to the first preset temperature difference, controlling the fixed mold temperature and the movable mold temperature to approach each other according to the PID controller so that the first temperature difference is equal to the first preset temperature difference;

[0024] If the first temperature difference is equal to the first preset temperature difference, a larger temperature between the fixed mold temperature and the movable mold temperature is determined as the current temperature of the mold.

[0025] Preferably, the first preset temperature difference has a value range of [5°, -5°].

[0026] Preferably, controlling the fixed mold temperature and the movable mold temperature to approach each other according to a PID controller comprises:

[0027] respectively obtaining error change rates of the fixed mold temperature and the movable mold temperature;

[0028] According to the first temperature difference and the error change rate, the first one-way valve, the second one-way valve, the third one-way valve and the fourth one-way valve are respectively controlled by the PID controller to operate at a target opening, wherein the mold includes a fixed mold and a movable mold, the fixed mold is provided with a first circuit channel, the first one-way valve and the second one-way valve are respectively installed at the water inlet and the water outlet of the first circuit channel, the movable mold is provided with a second circuit channel, the third one-way valve and the fourth one-way valve are respectively installed at the water inlet and the water outlet of the second circuit channel.

[0029] Preferably, the PID controller is used to control the first one-way valve, the second one-way valve, the third one-way valve and the fourth one-way valve to operate at target openings, including:

[0030] Target opening of the first check valve:

[0031] Target opening of the second check valve:

[0032] Target opening of the third check valve:

[0033] Target opening of the fourth check valve:

[0034]

[0035] Among them, U represents the PID control output, t represents the current time, E represents the first temperature difference, K p Represents proportional gain, K i Indicates the integral gain, K d Represents the differential gain.

[0036] Preferably, based on the current injection molding operation stage, determining the temperature control mode of the mold includes:

[0037] Based on the current action of the injection molding machine, the current injection molding operation stage is determined; wherein the current injection molding operation stage includes a mold closing stage, a filling stage, a pressure holding stage and a cooling stage,

[0038] When the current injection molding operation stage is a mold closing stage and a filling stage, determining that the temperature control mode of the mold is a heating mode; wherein the first set temperature value of the mold closing stage is less than the first set temperature value of the filling stage;

[0039] When the current injection molding operation stage is a holding stage and a cooling stage, the temperature control mode of the mold is determined to be a cooling mode; wherein the second set temperature value of the holding stage is greater than the second set temperature value of the cooling stage.

[0040] Preferably, cooling the mold to a target temperature corresponding to the current injection molding operation stage based on the current cooling operation comprises:

[0041] Obtaining a standard cooling slope corresponding to the current injection molding operation stage; wherein the standard cooling slope has standard temperature nodes corresponding to each moment, and the standard temperature node is a standard temperature node corresponding to the current temperature of the mold at the current moment;

[0042] Determine whether the current temperature of the mold is at a standard temperature node corresponding to the standard cooling slope;

[0043] If so, cooling the mold based on the current cooling operation;

[0044] If not, according to the difference between the current temperature of the mold and the temperature corresponding to the standard temperature node at the next moment in the standard cooling slope, the current temperature of the mold is controlled to be at the standard temperature node at the next moment in the standard cooling slope, and then the mold is cooled based on the current cooling operation.

[0045] In a second aspect, the present invention further provides a mold temperature control system based on precision injection molding, the system comprising:

[0046] A determination module, used to determine a temperature control mode of the mold based on the current injection molding operation stage; wherein the temperature control mode includes a heating mode and a cooling mode;

[0047] A heating control module, used to obtain the heating temperature rise rate and the current temperature change rate of the mold corresponding to the current injection molding operation stage, and obtain the compensation temperature rise rate of the mold according to the heating temperature rise rate and the current temperature change rate, determine the current heating operation performed on the mold according to the current temperature of the mold and the compensation temperature rise rate, and heat the mold to the target temperature corresponding to the current injection molding operation stage based on the current heating operation; wherein the current temperature change rate is the temperature change rate provided to the mold by the current environmental factors during the current injection molding operation stage, and the compensation temperature rise rate is equal to the difference between the heating temperature rise rate and the current temperature change rate;

[0048] A cooling control module is used to obtain the cooling rate and current temperature change rate of the mold corresponding to the current injection molding operation stage, and obtain the compensation cooling rate of the mold according to the cooling rate and the current temperature change rate, determine the current cooling operation performed on the mold according to the current temperature of the mold and the compensation cooling rate, and cool the mold to the target temperature corresponding to the current injection molding operation stage based on the current cooling operation; wherein the compensation cooling rate is equal to the addition of the cooling rate and the current temperature change rate.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] 1) The mold temperature control method based on precision injection molding provided by the present invention first determines the temperature control mode of the mold based on the current injection molding operation stage; the present invention can determine the corresponding temperature control mode to be executed on the mold according to the current injection molding operation stage, and can accurately heat or cool the mold to control the temperature change of the mold during the injection molding process to meet the current production needs in real time, avoid the mismatch between the mold temperature during the injection molding process and the actual injection molding needs, thereby avoiding defects such as seriously affecting the dimensional accuracy and quality of the injection molded products.

[0051] 2) In the heating mode, the heating temperature rise rate and the current temperature change rate of the mold corresponding to the current injection molding operation stage are obtained, and the compensation temperature rise rate of the mold is obtained according to the heating temperature rise rate and the current temperature change rate, and the current heating operation performed on the mold is determined according to the current temperature of the mold and the compensation temperature rise rate, and the mold is heated to the target temperature corresponding to the current injection molding operation stage based on the current heating operation; because during injection molding production, the heating operation and temperature required by the mold are different when corresponding to different injection molding stages, different ambient temperatures and different melt materials, and the temperature change needs to be strictly controlled during the molding process, and because the temperature change of the mold is not only subject to human control factors but also to uncontrollable factors, the present invention is based on the current temperature of the mold and the current temperature change rate, and comprehensively considers the relationship between the heating temperature rise rate of the mold and the current temperature change rate, so as to accurately obtain the compensation temperature rise rate corresponding to the mold at the current moment, and realize precise control of the mold temperature, so that the change of the mold temperature is more in line with the actual injection molding production situation, reduces the low precision of the product during the injection molding process, and improves product quality and injection molding efficiency.

[0052] 3) In cooling mode, the cooling rate and current temperature change rate of the mold corresponding to the current injection molding operation stage are obtained, and the compensation cooling rate of the mold is obtained according to the cooling rate and the current temperature change rate, and the current cooling operation performed on the mold is determined according to the current temperature of the mold and the compensation cooling rate, and the mold is cooled to the target temperature corresponding to the current injection molding operation stage based on the current cooling operation; because during injection molding production, the cooling operation and temperature required by the mold are different when corresponding to different injection molding stages, different ambient temperatures and different melt materials, and the temperature change needs to be strictly controlled during the molding process, and because the temperature change of the mold is not only subject to human control factors but also to uncontrollable factors, the present invention is based on the current temperature of the mold, and comprehensively considers the relationship between the heating rate of the mold and the current temperature change rate, so as to accurately obtain the compensation cooling rate corresponding to the mold at the current moment, and realize precise control of the mold temperature, so that the change of the mold temperature is more in line with the actual injection molding production situation, reduce the low precision of the product during the injection molding process, and improve product quality and injection molding efficiency.

[0053] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the background technology, the drawings required for use in the embodiments of the present invention or the background technology will be described below.

[0055] The drawings herein are incorporated into the specification and constitute a part of the specification. These drawings illustrate embodiments consistent with the present disclosure and are used to illustrate the technical solutions of the present disclosure together with the specification.

[0056] Figure 1 A schematic flow chart of a mold temperature control method based on precision injection molding provided by an embodiment of the present invention;

[0057] Figure 2 A schematic structural diagram of a mold temperature control system based on precision injection molding provided by an embodiment of the present invention;

[0058] Figure 3 A schematic diagram of the working principle of a mold temperature control system based on precision injection molding provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0059] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0060] The terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products or devices.

[0061] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0062] In addition, in order to better illustrate the present invention, numerous specific details are provided in the following specific embodiments. It should be understood by those skilled in the art that the present invention can be implemented without certain specific details. In some examples, methods, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present invention.

[0063] See also Figure 1 , Figure 1 The present invention provides a flow chart of a mold temperature control method based on precision injection molding. Figure 1 As shown, a mold temperature control method based on precision injection molding, the method comprises the following steps:

[0064] S10, determining a temperature control mode of the mold based on the current injection molding operation stage; wherein the temperature control mode includes a heating mode and a cooling mode;

[0065] It should be noted that the injection molding production stages generally include the mold closing stage, the filling stage, the pressure holding stage and the cooling stage, and the mold temperature corresponding to each stage is different. This application determines the temperature control mode of the mold based on the current injection molding operation stage, thereby achieving precise heating and cooling control of the mold and realizing precise control effect.

[0066] The following steps are involved:

[0067] S11, based on the current action of the injection molding machine, determining the current injection molding operation stage; wherein the current injection molding operation stage includes a mold closing stage, a filling stage, a pressure holding stage and a cooling stage,

[0068] The current action of the injection molding machine includes door closing action, mold closing action, screw rotation and screw travel, etc., so as to determine the current injection molding operation stage according to the current action of the injection molding machine.

[0069] S12, when the current injection molding operation stage is a mold closing stage and a filling stage, determining that the temperature control mode of the mold is a heating mode; wherein the first set temperature value of the mold closing stage is less than the first set temperature value of the filling stage;

[0070] It should be noted that the heating mode refers to the overall trend from the current temperature of the mold to the temperature at the end of the stage, which is a heating temperature rising state or a heating constant temperature state, that is, the temperature at the end of the stage is greater than the current temperature of the mold.

[0071] S13. When the current injection molding operation stage is a pressure holding stage and a cooling stage, determine that the temperature control mode of the mold is a cooling mode; wherein the second set temperature value of the pressure holding stage is greater than the second set temperature value of the cooling stage.

[0072] It should be noted that the cooling mode refers to the overall trend from the current temperature of the mold to the temperature at the end of the stage, which is a cooling state or a cooling constant temperature state, that is, the temperature at the end of the stage is lower than the current temperature of the mold.

[0073] In one embodiment, the method further includes obtaining the current temperature of the mold, specifically, including:

[0074] S14, acquiring a fixed mold temperature of the mold, a movable mold temperature of the mold, and a first temperature difference between the fixed mold temperature and the movable mold temperature;

[0075] S15, if the first temperature difference is not equal to the first preset temperature difference, controlling the fixed mold temperature and the movable mold temperature to approach each other according to the PID controller so that the first temperature difference is equal to the first preset temperature difference;

[0076] It should be noted that different injection molding products, molds or production requirements have corresponding fixed mold and movable mold temperature requirements. Therefore, the first preset temperature difference is set accordingly according to the actual production requirements, and the fixed mold temperature and the movable mold temperature are controlled to approach each other through the PID controller so that the first temperature difference is equal to the first preset temperature difference, thereby ensuring the quality and precision of the corresponding injection molding products; such as: the first preset temperature difference corresponding to the current actual production is 0, that is, the fixed mold temperature and the movable mold temperature are set the same, or, the first preset temperature difference corresponding to the current actual production is 1, that is, the fixed mold temperature is greater than the movable mold temperature, and the fixed mold temperature-moving mold temperature=1, or, the first preset temperature difference corresponding to the current actual production is -1, that is, the fixed mold temperature is less than the movable mold temperature, and the fixed mold temperature-moving mold temperature=-1.

[0077] In one embodiment, controlling the fixed mold temperature and the movable mold temperature to approach each other according to a PID controller includes:

[0078] S151, respectively obtaining the error change rates of the fixed mold temperature and the movable mold temperature;

[0079] S152, according to the first temperature difference and the error change rate, respectively controlling the first one-way valve, the second one-way valve, the third one-way valve and the fourth one-way valve to operate at a target opening through the PID controller, wherein, Figure 3 As shown, the mold includes a fixed mold and a movable mold, the fixed mold is provided with a first circuit channel, the first one-way valve and the second one-way valve are respectively installed at the water inlet and the water outlet of the first circuit channel, the movable mold is provided with a second circuit channel, the third one-way valve and the fourth one-way valve are respectively installed at the water inlet and the water outlet of the second circuit channel, the water inlet and the water outlet of the first circuit channel and the second circuit channel are respectively connected by a heater, so as to realize heating of the medium flowing to the fixed mold and the movable mold, the water inlet and the water outlet of the first circuit channel and the second circuit channel are also provided with a temperature sensor and a flow sensor, wherein the water inlet of the heater is also connected to a cooling water delivery pipe, the water outlet of the heater is connected to a cooling water output pipe, and the cooling water delivery pipe and the cooling water output pipe are both provided with a one-way valve and a flow sensor.

[0080] In one embodiment, the PID controller is used to control the first one-way valve, the second one-way valve, the third one-way valve and the fourth one-way valve to operate at target openings, including:

[0081] Target opening of the first check valve:

[0082] Target opening of the second check valve:

[0083] Target opening of the third check valve:

[0084] Target opening of the fourth check valve:

[0085]

[0086] Among them, U represents the PID control output, t represents the current time, E represents the first temperature difference, K p Represents proportional gain, K i Indicates the integral gain, K d Represents the differential gain.

[0087] It should be noted that the first one-way valve, the second one-way valve, the third one-way valve and the fourth one-way valve are all one-way valves. By adjusting the opening of the one-way valve, the water flow at the water inlet and the water outlet changes, thereby achieving a phase adjustment of the fixed mold temperature and the movable mold temperature.

[0088] In one embodiment, it also includes: controlling the one-way valve of the cooling water delivery pipe and the heating power of the heater to operate at the target opening by the PID controller, so as to adjust the temperature of the water delivered to the fixed mold and the movable mold through the water inlet to change, thereby achieving the close adjustment of the fixed mold temperature and the movable mold temperature, improving the adjustment accuracy and efficiency, avoiding energy waste, and improving the energy efficiency of the heater. When the temperature of the water delivered to the fixed mold and the movable mold through the water inlet does not meet the preset temperature, the one-way valve of the cooling water output pipe is controlled to open to output the water that does not meet the preset temperature to avoid affecting the temperature of the mold. When the temperature of the water delivered to the fixed mold and the movable mold through the water inlet meets the preset temperature, the first one-way valve, the second one-way valve, the third one-way valve and the fourth one-way valve are respectively controlled to operate at the target opening.

[0089] S43: If the first temperature difference is equal to the first preset temperature difference, and the first preset temperature difference is not 0, determine a larger temperature between the fixed mold temperature and the movable mold temperature as the current temperature of the mold.

[0090] If the first temperature difference is equal to the first preset temperature difference, and the first preset temperature difference is 0, the fixed mold temperature or the movable mold temperature is determined as the current temperature of the mold.

[0091] S20. In the heating mode, the heating temperature rise rate and the current temperature change rate of the mold corresponding to the current injection molding operation stage are obtained, and the compensation temperature rise rate of the mold is obtained according to the heating temperature rise rate and the current temperature change rate, and the current heating operation performed on the mold is determined according to the current temperature of the mold and the compensation temperature rise rate, and the mold is heated to the target temperature corresponding to the current injection molding operation stage based on the current heating operation; wherein, the current temperature change rate is the temperature change rate provided to the mold by the current environmental factors during the current injection molding operation stage, and the compensation temperature rise rate is equal to the difference between the heating temperature rise rate and the current temperature change rate; the current environmental factors include the temperature of the current environment and the temperature of the current melt material; the compensation temperature rise rate is the temperature change rate provided to the mold by the medium in the current circuit channel during the current injection molding operation stage.

[0092] It should be noted that due to the high requirements of precision injection molding on the mold temperature, a temperature control system is usually provided, but the temperature control system is usually only provided with a conventional cooling mode, and the conventional cooling mode alone often cannot effectively guarantee the accuracy and quality of the injection molded products. Therefore, in order to improve the filling performance, the present invention is not only provided with a cooling mode, but also with a corresponding heating mode, so as to heat the mold before injection molding, thereby accurately controlling the temperature of the mold to meet the plastic forming process requirements at the heating rate.

[0093] In addition, during the injection molding process, the mold is not only affected by the temperature control system, but also by the temperature of the melt material and the temperature of the current environment. For example, the temperature difference between summer and winter is very large, and the temperature difference between the north and the south is also very large. Similarly, the melting points of different injection molding materials are also different. If the temperature cannot be accurately controlled according to the actual situation, the production quality will often be reduced, resulting in an increase in the unqualified rate and production costs. Therefore, determining the compensatory heating rate of the mold by the temperature control system based on the heating heating rate and the current temperature change rate can actually solve the above problems.

[0094] If the current temperature change rate is greater than the heating temperature rise rate, the compensated temperature rise rate is used as the compensated temperature drop rate, and the current cooling operation performed on the mold is determined based on the compensated temperature drop rate. The mold is cooled according to the current cooling operation so that the mold is heated at the heating temperature rise rate.

[0095] It should be noted that during injection, due to the high temperature of the molten material, the temperature of the mold is often quickly heated. At this time, the current temperature change rate acts on the mold to heat the mold. At the same time, in order to avoid the temperature provided by the current temperature change rate to the mold causing the temperature of the mold to be higher than the plastic forming process requirements, the temperature of the mold is adjusted by using the compensation heating rate as the compensation cooling rate, so that the temperature of the mold is heated according to the heating rate to the target temperature corresponding to the current injection molding operation stage, thereby ensuring the quality and precision of the injection molded products.

[0096] The current temperature change rate is calculated based on the temperature of the melt material, the ambient temperature and the specific heat capacity of the mold; for example, the current temperature change rate includes:

[0097]

[0098] It is the temperature change rate provided by the current environmental factors to the mold;

[0099] Q 熔体 It is the heat transferred from the molten material to the mold;

[0100] Q 环境 is the rate at which heat is transferred from the die to the environment.

[0101] C m is the heat capacity of the mold.

[0102] The rate at which the molten material transfers heat to the mold includes:

[0103]

[0104] In the formula, k 熔体 is the thermal conductivity of the melt material; A 熔体 is the conductive contact area of ​​the molten material; T 熔体 is the temperature of the melt material; T m is the current temperature of the mold; d 熔体 is the conduction distance of the molten material.

[0105] The heat transferred from the mold to the environment includes:

[0106]

[0107] In the formula, k 环境 is the thermal conductivity of the environment; A 环境 is the conductive contact area to the environment; T 环境 is the temperature of the environment; T m is the current temperature of the mold; d 环境 is the conduction distance of the environment.

[0108] The heat capacity of the mold includes: C m =m*c; where m is the mold mass and c is the specific heat capacity of the mold material.

[0109] Compensated heating rates include:

[0110]

[0111] It should be noted that injection molded products are obtained by heating the injection molding material through an injection molding machine to make it reach a molten state, and applying high pressure to the molten material after reaching the molten state, so that it is ejected and fills the mold cavity, and then is obtained after pressure holding and cooling; therefore, the mold is set close to the melting zone of the injection molding material in the actual production process, and is injected into the mold after melting. It can be seen that the environment of the mold has a certain temperature, and this temperature can affect the temperature of the mold. Similarly, after the molten material is injected into the mold, the high-temperature molten material enters the low-temperature mold, which will quickly affect the temperature change of the mold.

[0112] In one embodiment, determining a current heating operation performed on the mold according to the current temperature of the mold and the compensated heating rate includes:

[0113] S201, obtaining a target medium flow rate and a target medium temperature delivered to the mold loop channel based on the compensated heating rate;

[0114] S202, determining the operating power of the heater based on the target medium temperature, the medium temperature in the heater, and the medium capacity;

[0115] S203, determining target openings of the first one-way valve, the second one-way valve, the third one-way valve, and the fourth one-way valve based on the target medium flow rate;

[0116] S204, controlling the operation of the heater based on the operating power of the heater;

[0117] S205, based on and controlling the first one-way valve, the second one-way valve, the third one-way valve and the fourth one-way valve to operate at the target opening;

[0118] S206, when the medium capacity or liquid level in the heater is lower than the standard range, a first medium compensation amount is determined based on the medium capacity or liquid level, and a second medium compensation amount is obtained according to the medium input amount and the medium output amount of the mold circuit channel, and a compensation target opening and a target operating time are obtained according to the first medium compensation amount and the second medium compensation amount, and a one-way valve on the cooling water delivery pipe is controlled to operate the target operating time at the compensation target opening so that the medium capacity or liquid level in the heater is within the standard range, and the operating power of the heater is adjusted based on the medium flow rate and the medium temperature delivered by the cooling water delivery pipe, and the heater is controlled to operate for the target operating time based on the adjusted operating power;

[0119] S207. When it is detected that the temperature of the medium delivered to the mold loop channel does not meet the target medium temperature, if the temperature of the medium delivered to the mold loop channel is greater than the target medium temperature, the first one-way valve, the second one-way valve, the third one-way valve and the fourth one-way valve are controlled to operate at the minimum opening, and the one-way valves on the cooling water delivery pipe and the cooling water output pipe are controlled to open, and the operating power of the heater is reduced at the same time; if the temperature of the medium delivered to the mold loop channel is lower than the target medium temperature, the first one-way valve, the second one-way valve, the third one-way valve and the fourth one-way valve are controlled to be closed, and the one-way valve on the cooling water output pipe is controlled to be opened to discharge the medium output by the heater, and the operating power of the heater is increased at the same time and the one-way valve on the cooling water delivery pipe is controlled to be opened according to a preset opening rule, and the preset opening rule is configured to gradually increase the opening angle.

[0120] The compensation heating rate also includes:

[0121]

[0122] is the compensation heating rate, that is, the temperature change rate provided by the medium in the current circuit channel to the mold;

[0123] Q 介质 It is the heat transferred from the medium in the circuit channel to the mold;

[0124] C m is the heat capacity of the mold.

[0125] The heat transferred from the medium in the circuit channel to the mold includes:

[0126]

[0127] In the formula, k 介质 is the thermal conductivity of the medium; A 介质 is the conductive contact area of ​​the medium; T 介质 is the temperature of the medium; T m is the current temperature of the mold; d介质 is the conduction distance of the medium.

[0128] In one of the embodiments, the first preset temperature difference value ranges from [5°, -5°].

[0129] In one embodiment, heating the mold to a target temperature corresponding to the current injection molding operation stage based on the current heating operation comprises:

[0130] S21, obtaining a standard temperature rise slope corresponding to the heating temperature rise rate; wherein the standard temperature rise slope has standard temperature nodes corresponding to each moment, and the standard temperature node is a standard temperature node corresponding to the current temperature of the mold at the current moment;

[0131] In one embodiment, obtaining a standard temperature rise slope corresponding to the heating temperature rise rate comprises:

[0132] S211, obtaining heat changes of the mold in each injection molding operation stage in the heating mode based on a simulation calculation tool, and drawing a predicted temperature-time curve corresponding to each injection molding operation stage according to the heat changes and the time nodes corresponding to when the current temperature of the mold is obtained at each moment;

[0133] S212, determining the heating time required for the mold in the current injection molding operation stage based on the predicted temperature-time curve, wherein the heating time satisfies a preset production cycle;

[0134] S213, according to the predicted temperature-time curve and the heating time, using an experimental method to obtain a plurality of heat distribution diagrams of the mold in each injection molding operation stage in the heating mode, an actual temperature-time curve obtained based on the plurality of heat distribution diagrams, and a quality evaluation result of the injection molded product formed based on the actual temperature-time curve and the heating time; wherein the quality evaluation result includes dimensional accuracy;

[0135] S214, based on the dimensional accuracy of the injection molded product, the actual temperature-time curve is optimized, if the dimensional accuracy of the injection molded product after the optimization is not within the allowable error range, the actual temperature-time curve corresponding to the last optimization is determined as the optimal actual temperature-time curve; wherein the duration of the heating time after each optimization is sequentially reduced, and the dimensional accuracy of the injection molded product corresponding to the optimal actual temperature-time curve is within the allowable error range;

[0136] S215, obtaining the heating temperature rise rate based on the optimal actual temperature-time curve, and using the optimal actual temperature-time curve as a standard temperature rise slope corresponding to the heating temperature rise rate;

[0137] It should be noted that the heating temperature rise rate can be the heating temperature rise rate of the mold at the next moment or the heating temperature rise rate corresponding to the current injection molding operation stage, which is specifically determined according to the optimal actual temperature-time curve. For example, when the optimal actual temperature-time curve is a regular heating curve, the heating temperature rise rate is the heating temperature rise rate corresponding to the mold at the current injection molding operation stage; when the optimal actual temperature-time curve is an irregular heating curve, the heating temperature rise rate is the heating temperature rise rate of the mold at the next moment; the specific setting can be made according to the actual production situation.

[0138] S216. Determine the actual heating time and target temperature required for the mold in the current injection molding operation stage according to the heating temperature rise rate and the standard temperature rise slope, and obtain the corresponding standard temperature node based on the time node.

[0139] S22, determining whether the current temperature of the mold is at a standard temperature node corresponding to the standard temperature rise slope;

[0140] S23, if yes, heating the mold at the heating temperature rising rate;

[0141] S24. If not, based on the difference between the current temperature of the mold and the temperature corresponding to the standard temperature node at the next moment in the standard temperature ramp, control the current temperature of the mold to be at the standard temperature node at the next moment in the standard temperature ramp at the next moment, and then heat the mold at the heating rate.

[0142] In one embodiment, determining a current heating operation corresponding to the mold according to the current temperature of the mold and the compensated heating rate, and heating the mold to the first set temperature based on the current heating operation includes:

[0143] According to the current temperature of the mold and the compensation heating rate, the PID controller controls the one-way valve of the cooling water delivery pipe, the heating power of the heater, the first one-way valve, the second one-way valve, the third one-way valve and the fourth one-way valve to operate at the corresponding target openings, so that the mold is heated and heated at the heating rate. This achieves accurate and efficient control of the change in mold temperature during the injection molding process.

[0144] In one embodiment, according to the difference between the current temperature of the mold and the temperature corresponding to the standard temperature node at the next moment in the standard temperature ramp, controlling the current temperature of the mold to be at the standard temperature node at the next moment in the standard temperature ramp at the next moment, comprises:

[0145] According to the current temperature of the mold and the current temperature change rate, the PID controller controls the one-way valve of the cooling water delivery pipe, the heating power of the heater, the first one-way valve, the second one-way valve, the third one-way valve and the fourth one-way valve to operate at the corresponding target openings, so that the temperature of the mold at the next moment is at the standard temperature node corresponding to the standard temperature rise slope, thereby achieving accurate and efficient control of the change of the mold temperature during the injection molding process.

[0146] S30. In cooling mode, the cooling rate and current temperature change rate of the mold corresponding to the current injection molding operation stage are obtained, and the compensation cooling rate of the mold is obtained according to the cooling rate and the current temperature change rate, and the current cooling operation performed on the mold is determined according to the current temperature of the mold and the compensation cooling rate, and the mold is cooled to the target temperature corresponding to the current injection molding operation stage based on the current cooling operation; wherein the compensation cooling rate is equal to the sum of the cooling rate and the current temperature change rate. The compensation cooling rate is the temperature change rate provided to the mold by the medium in the current circuit channel during the current injection molding operation stage.

[0147] In one embodiment, determining a current cooling operation performed on the mold according to the current temperature of the mold and the compensated cooling rate includes:

[0148] Based on the compensated cooling rate, a target cooling medium flow rate and a target cooling medium temperature delivered to the mold circuit channel are obtained;

[0149] If the target cooling medium temperature is lower than the medium flow delivered by the cooling water delivery pipe, the heater is turned off; based on the target cooling medium flow, the first one-way valve, the second one-way valve, the third one-way valve and the fourth one-way valve are controlled to operate at the maximum opening, and according to the medium flow delivered to the mold circuit channel or the target cooling medium flow, the one-way valve on the cooling water delivery pipe is controlled to open, so that the output flow of the cooling water delivery pipe is equal to the medium flow delivered to the mold circuit channel, or the output flow of the cooling water delivery pipe is equal to the sum of the medium flow delivered to the fixed mold circuit channel and the medium flow delivered to the movable mold circuit channel; at this time, the medium output by the mold circuit channel passes through the heater and is delivered to the mold; the one-way valve on the cooling output pipe connected to the mold is controlled to open, so that the medium output by the mold circuit channel is directly output from the cooling output pipe connected to the mold, and at this time, the medium output by the mold circuit channel does not pass through the heater;

[0150] If the target cooling medium temperature is higher than the medium flow rate delivered by the cooling water delivery pipe, and the target cooling medium temperature is lower than the medium temperature output by the mold loop channel, the one-way valve on the cooling output pipe connected to the mold is controlled to open, so that the medium output by the mold loop channel is directly output from the cooling output pipe connected to the mold. At this time, the medium output by the mold loop channel does not pass through the heater; and according to the target cooling medium temperature and the medium temperature in the heater, the operating power of the heater is determined, and the heater is controlled to operate at the operating power; based on the target medium flow rate, the target openings of the first one-way valve, the second one-way valve, the third one-way valve and the fourth one-way valve are determined; and the first one-way valve, the second one-way valve, the third one-way valve and the fourth one-way valve are controlled to operate at the target openings.

[0151] In one embodiment, cooling the mold to a target temperature corresponding to the current injection molding operation stage based on the current cooling operation comprises:

[0152] S31, obtaining a standard cooling slope corresponding to the cooling rate; wherein the standard cooling slope has standard temperature nodes corresponding to each moment, and the standard temperature nodes are standard temperature nodes corresponding to the current temperature of the mold at the current moment;

[0153] S32, determining whether the current temperature of the mold is at a standard temperature node corresponding to the standard cooling slope;

[0154] S33: If yes, cool the mold based on the current cooling operation;

[0155] S34. If not, according to the difference between the current temperature of the mold and the temperature corresponding to the standard temperature node at the next moment in the standard cooling slope, control the current temperature of the mold to be at the standard temperature node at the next moment in the standard cooling slope at the next moment, and then cool the mold based on the current cooling operation.

[0156] It should be noted that, since the acquisition methods of the standard heating ramp and the standard cooling ramp are corresponding, and the cooling mode is after the heating mode, that is, the one-time injection molding process includes the heating mode and the cooling mode, according to the sequence of the injection molding operation stages, the heating mode is executed first and then the cooling mode is executed. Therefore, the predicted temperature-time curves in the heating mode and the cooling mode can be simultaneously tuned in the one-time injection molding process, or separately tuned. For example, when tuning simultaneously, the predicted temperature-time curves in the heating mode and the cooling mode can also be tuned simultaneously by an experimental method. When tuning separately, the predicted temperature-time curve in one mode is first tuned by an experimental method, and the predicted temperature-time curve in the other mode remains unchanged until the predicted temperature-time curve in one mode is the optimal actual temperature-time curve. Based on the optimal actual temperature-time curve, the predicted temperature-time curve in the other mode is tuned, thereby obtaining the standard heating ramp and the standard cooling ramp. Among them, the steps in the cooling mode are set corresponding to the steps in the heating mode.

[0157] The present invention includes the following beneficial effects:

[0158] 1) The mold temperature control method based on precision injection molding provided by the present invention first determines the temperature control mode of the mold based on the current injection molding operation stage; the present invention can determine the corresponding temperature control mode to be executed on the mold according to the current injection molding operation stage, and can accurately heat or cool the mold to control the temperature change of the mold during the injection molding process to meet the current production needs in real time, avoid the mismatch between the mold temperature during the injection molding process and the actual injection molding needs, thereby avoiding defects such as seriously affecting the dimensional accuracy and quality of the injection molded products.

[0159] 2) In the heating mode, the heating temperature rise rate and the current temperature change rate of the mold corresponding to the current injection molding operation stage are obtained, and the compensation temperature rise rate of the mold is obtained according to the heating temperature rise rate and the current temperature change rate, and the current heating operation performed on the mold is determined according to the current temperature of the mold and the compensation temperature rise rate, and the mold is heated to the target temperature corresponding to the current injection molding operation stage based on the current heating operation; because during injection molding production, the heating operation and temperature required by the mold are different when corresponding to different injection molding stages, different ambient temperatures and different melt materials, and the temperature change needs to be strictly controlled during the molding process, and because the temperature change of the mold is not only subject to human control factors but also to uncontrollable factors, the present invention is based on the current temperature of the mold and the current temperature change rate, and comprehensively considers the relationship between the heating temperature rise rate of the mold and the current temperature change rate, so as to accurately obtain the compensation temperature rise rate corresponding to the mold at the current moment, and realize precise control of the mold temperature, so that the change of the mold temperature is more in line with the actual injection molding production situation, reduces the low precision of the product during the injection molding process, and improves product quality and injection molding efficiency.

[0160] 3) In cooling mode, the cooling rate and current temperature change rate of the mold corresponding to the current injection molding operation stage are obtained, and the compensation cooling rate of the mold is obtained according to the cooling rate and the current temperature change rate, and the current cooling operation performed on the mold is determined according to the current temperature of the mold and the compensation cooling rate, and the mold is cooled to the target temperature corresponding to the current injection molding operation stage based on the current cooling operation; because during injection molding production, the cooling operation and temperature required by the mold are different when corresponding to different injection molding stages, different ambient temperatures and different melt materials, and the temperature change needs to be strictly controlled during the molding process, and because the temperature change of the mold is not only subject to human control factors but also to uncontrollable factors, the present invention is based on the current temperature of the mold, and comprehensively considers the relationship between the heating rate of the mold and the current temperature change rate, so as to accurately obtain the compensation cooling rate corresponding to the mold at the current moment, and realize precise control of the mold temperature, so that the change of the mold temperature is more in line with the actual injection molding production situation, reduce the low precision of the product during the injection molding process, and improve product quality and injection molding efficiency.

[0161] 4) A loop channel is introduced into the mold by using the flow channel system, and the power of the heater connected to the loop channel is accurately controlled to achieve heating or cooling of the medium temperature, and the temperature of the medium delivered to the mold is accurately adjusted. At the same time, combined with the opening angle of the one-way valve of the cooling delivery pipe, the heated or cooled medium is delivered to the mold at a target flow rate, thereby achieving accurate adjustment of the mold temperature. By applying a PID (proportional-integral-differential) control algorithm, the heating or cooling system is automatically adjusted according to the temperature data fed back by the sensor to achieve stable control of the mold temperature. Among them, multiple temperature sensors are set at different positions of the mold to monitor the temperature changes of different parts in real time to ensure that the temperature of the entire mold is uniform and stable. The present invention can achieve accurate adjustment and stable control of the mold temperature, thereby improving production efficiency, product quality and production stability.

[0162] See also Figure 2 , Figure 2 The following is a schematic diagram of a mold temperature control system based on precision injection molding provided by an embodiment of the present invention. Figure 2 As shown, the present invention also provides a mold temperature control system based on precision injection molding, the system comprising:

[0163] The determination module 100 is used to determine the temperature control mode of the mold based on the current injection molding operation stage; wherein the temperature control mode includes a heating mode and a cooling mode;

[0164] The heating control module 200 is used to obtain the heating temperature rise rate and the current temperature change rate of the mold corresponding to the current injection molding operation stage; and obtain the compensation temperature rise rate of the mold according to the heating temperature rise rate and the current temperature change rate, determine the current heating operation performed on the mold according to the current temperature of the mold and the compensation temperature rise rate, and heat the mold to the target temperature corresponding to the current injection molding operation stage based on the current heating operation; wherein the current temperature change rate is the temperature change rate provided to the mold by the current environmental factors during the current injection molding operation stage, and the heating temperature rise rate is equal to the sum of the current temperature change rate and the compensation temperature rise rate;

[0165] The cooling control module 300 is used to obtain the cooling rate and current temperature change rate of the mold corresponding to the current injection molding operation stage; and obtain the compensation cooling rate of the mold according to the cooling rate and the current temperature change rate, determine the current cooling operation performed on the mold according to the current temperature of the mold and the compensation cooling rate, and cool the mold to the target temperature corresponding to the current injection molding operation stage based on the current cooling operation; wherein the cooling rate is equal to the difference between the current temperature change rate and the compensation cooling rate.

[0166] It can be understood that the functions or modules included in the system provided in this embodiment can be used to execute the method described in the above method embodiment. Its specific implementation can refer to the description of the above method embodiment. For the sake of brevity, it will not be repeated here.

[0167] See also Figure 3 , Figure 3 The following is a schematic diagram of the working principle of a mold temperature control system based on precision injection molding provided by an embodiment of the present invention. Figure 3 As shown, the present invention also provides a mold temperature control system based on precision injection molding.

[0168] The present invention also provides an electronic device, including a processor and a memory, wherein the memory is used to store computer program code, and the computer program code includes computer instructions. When the processor executes the computer instructions, the electronic device executes a method as described in any possible implementation manner.

[0169] The present invention also provides a computer-readable storage medium, in which a computer program is stored. The computer program includes program instructions. When the program instructions are executed by a processor of an electronic device, the processor executes a method as described in any possible implementation manner.

[0170] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0171] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments, and will not be repeated here. Those skilled in the art can also clearly understand that the descriptions of the various embodiments of the present invention have different focuses. For the convenience and brevity of description, the same or similar parts may not be repeated in different embodiments. Therefore, for parts not described or not described in detail in a certain embodiment, refer to the records of other embodiments.

[0172] In the several embodiments provided by the present invention, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0173] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0174] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented by software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present invention is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted through the computer-readable storage medium. The computer instructions can be transmitted from a website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (digital subscriber line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that includes one or more available media integrated. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a digital versatile disc (DVD)), or a semiconductor medium (eg, a solid state disk (SSD)).

[0175] A person skilled in the art can understand that to implement all or part of the processes in the above-mentioned embodiments, the processes can be completed by a computer program to instruct the relevant hardware, and the program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the above-mentioned method embodiments. The aforementioned storage medium includes: a read-only memory (ROM) or a random access memory (RAM), a magnetic disk or an optical disk, and other media that can store program codes.

Claims

1. A mold temperature control method based on precision injection molding, characterized in that: The method comprises the following steps: Based on the current injection molding operation stage, determining the temperature control mode of the mold; wherein the temperature control mode includes a heating mode and a cooling mode; In the heating mode, the heating temperature rise rate and the current temperature change rate of the mold corresponding to the current injection molding operation stage are obtained, and the compensation temperature rise rate of the mold is obtained according to the heating temperature rise rate and the current temperature change rate, and the current heating operation performed on the mold is determined according to the current temperature of the mold and the compensation temperature rise rate, and the mold is heated to the target temperature corresponding to the current injection molding operation stage based on the current heating operation; wherein the current temperature change rate is the temperature change rate provided to the mold by the current environmental factors during the current injection molding operation stage, and the compensation temperature rise rate is equal to the difference between the heating temperature rise rate and the current temperature change rate; In cooling mode, the cooling rate and current temperature change rate of the mold corresponding to the current injection molding operation stage are obtained, and the compensation temperature drop rate of the mold is obtained according to the cooling rate and the current temperature change rate, and the current cooling operation performed on the mold is determined according to the current temperature of the mold and the compensation temperature drop rate, and the mold is cooled to the target temperature corresponding to the current injection molding operation stage based on the current cooling operation; wherein the compensation temperature drop rate is equal to the sum of the cooling rate and the current temperature change rate; Wherein, the current temperature of the mold includes: Acquire a fixed mold temperature of the mold, a movable mold temperature of the mold, and a first temperature difference between the fixed mold temperature and the movable mold temperature; If the first temperature difference is not equal to the first preset temperature difference, controlling the fixed mold temperature and the movable mold temperature to approach each other according to the PID controller so that the first temperature difference is equal to the first preset temperature difference; If the first temperature difference is equal to the first preset temperature difference, a larger temperature between the fixed mold temperature and the movable mold temperature is determined as the current temperature of the mold.

2. The mold temperature control method based on precision injection molding according to claim 1, characterized in that: Heating the mold to a target temperature corresponding to the current injection molding operation stage based on the current heating operation; comprising: Obtaining a standard temperature rise slope corresponding to the heating temperature rise rate; wherein the standard temperature rise slope has standard temperature nodes corresponding to each moment, and the standard temperature node is a standard temperature node corresponding to the current temperature of the mold at the current moment; Determine whether the current temperature of the mold is at a standard temperature node corresponding to the standard temperature rise slope; If so, heating the mold based on the current heating operation; If not, based on the difference between the current temperature of the mold and the temperature corresponding to the standard temperature node at the next moment in the standard heating ramp, the current temperature of the mold is controlled to be at the standard temperature node at the next moment in the standard heating ramp, and then the mold is heated based on the current heating operation.

3. The mold temperature control method based on precision injection molding according to claim 2 is characterized in that: Obtaining a standard temperature rise slope corresponding to the heating temperature rise rate; comprising: Obtaining heat changes of the mold in each injection molding operation stage in a heating mode based on a simulation calculation tool, and drawing a predicted temperature-time curve corresponding to each injection molding operation stage according to the heat changes and the time nodes corresponding to when the current temperature of the mold is obtained at each moment; Based on the predicted temperature-time curve, determining the heating time required for the mold in the current injection molding operation stage, wherein the heating time satisfies a preset production cycle; According to the predicted temperature-time curve and the heating time, an experimental method is used to obtain a plurality of heat distribution diagrams of the mold in each injection molding operation stage in a heating mode, an actual temperature-time curve obtained based on the plurality of heat distribution diagrams, and a quality evaluation result of the injection molded product formed based on the actual temperature-time curve and the heating time; wherein the quality evaluation result includes dimensional accuracy; Based on the dimensional accuracy of the injection molded product, the actual temperature-time curve is optimized. If the dimensional accuracy of the injection molded product after the optimization is not within the allowable error range, the actual temperature-time curve corresponding to the last optimization is determined as the optimal actual temperature-time curve; wherein the duration of the heating time after each optimization is sequentially reduced, and the dimensional accuracy of the injection molded product corresponding to the optimal actual temperature-time curve is within the allowable error range; Based on the optimal actual temperature-time curve, the heating temperature rise rate is obtained, and the optimal actual temperature-time curve is used as a standard temperature rise slope corresponding to the heating temperature rise rate; According to the heating temperature rise rate and the standard temperature rise slope, the actual heating time and target temperature required for the mold in the current injection molding operation stage are determined, and the corresponding standard temperature node is obtained based on the time node.

4. The mold temperature control method based on precision injection molding according to claim 1, characterized in that: The value range of the first preset temperature difference is [5°, -5°].

5. The mold temperature control method based on precision injection molding according to claim 1, characterized in that: Controlling the fixed mold temperature and the movable mold temperature to approach each other according to the PID controller includes: respectively obtaining error change rates of the fixed mold temperature and the movable mold temperature; According to the first temperature difference and the error change rate, the first one-way valve, the second one-way valve, the third one-way valve and the fourth one-way valve are respectively controlled by the PID controller to operate at a target opening, wherein the mold includes a fixed mold and a movable mold, the fixed mold is provided with a first circuit channel, the first one-way valve and the second one-way valve are respectively installed at the water inlet and the water outlet of the first circuit channel, the movable mold is provided with a second circuit channel, the third one-way valve and the fourth one-way valve are respectively installed at the water inlet and the water outlet of the second circuit channel.

6. The mold temperature control method based on precision injection molding according to claim 5, characterized in that: The PID controller is used to control the first one-way valve, the second one-way valve, the third one-way valve and the fourth one-way valve to operate at a target opening, including: Target opening of the first check valve: Target opening of the second check valve: Target opening of the third check valve: Target opening of the fourth check valve: Among them, U represents the PID control output, t represents the current time, E represents the first temperature difference, K p Represents proportional gain, K i Indicates the integral gain, K d Represents the differential gain.

7. The mold temperature control method based on precision injection molding according to claim 1, characterized in that: Determine the temperature control mode of the mold based on the current injection molding operation stage; including: Based on the current action of the injection molding machine, the current injection molding operation stage is determined; wherein the current injection molding operation stage includes a mold closing stage, a filling stage, a pressure holding stage and a cooling stage, When the current injection molding operation stage is a mold closing stage and a filling stage, determining that the temperature control mode of the mold is a heating mode; wherein the first set temperature value of the mold closing stage is less than the first set temperature value of the filling stage; When the current injection molding operation stage is a holding stage and a cooling stage, the temperature control mode of the mold is determined to be a cooling mode; wherein the second set temperature value of the holding stage is greater than the second set temperature value of the cooling stage.

8. The mold temperature control method based on precision injection molding according to claim 1, characterized in that: Cooling the mold to a target temperature corresponding to the current injection molding operation stage based on the current cooling operation; comprising: Obtaining a standard cooling slope corresponding to the current injection molding operation stage; wherein the standard cooling slope has standard temperature nodes corresponding to each moment, and the standard temperature node is a standard temperature node corresponding to the current temperature of the mold at the current moment; Determine whether the current temperature of the mold is at a standard temperature node corresponding to the standard cooling slope; If so, cooling the mold based on the current cooling operation; If not, according to the difference between the current temperature of the mold and the temperature corresponding to the standard temperature node at the next moment in the standard cooling slope, the current temperature of the mold is controlled to be at the standard temperature node at the next moment in the standard cooling slope, and then the mold is cooled based on the current cooling operation.

9. A mold temperature control system based on precision injection molding, characterized in that: The system comprises: A determination module, used to determine a temperature control mode of the mold based on the current injection molding operation stage; wherein the temperature control mode includes a heating mode and a cooling mode; A heating control module, used to obtain the heating temperature rise rate and the current temperature change rate of the mold corresponding to the current injection molding operation stage, and obtain the compensation temperature rise rate of the mold according to the heating temperature rise rate and the current temperature change rate, determine the current heating operation performed on the mold according to the current temperature of the mold and the compensation temperature rise rate, and heat the mold to the target temperature corresponding to the current injection molding operation stage based on the current heating operation; wherein the current temperature change rate is the temperature change rate provided to the mold by the current environmental factors during the current injection molding operation stage, and the compensation temperature rise rate is equal to the difference between the heating temperature rise rate and the current temperature change rate; A cooling control module, used to obtain the cooling rate and current temperature change rate of the mold corresponding to the current injection molding operation stage, and obtain the compensation cooling rate of the mold according to the cooling rate and the current temperature change rate, determine the current cooling operation performed on the mold according to the current temperature of the mold and the compensation cooling rate, and cool the mold to the target temperature corresponding to the current injection molding operation stage based on the current cooling operation; wherein the compensation cooling rate is equal to the sum of the cooling rate and the current temperature change rate; Wherein, the current temperature of the mold includes: Acquire a fixed mold temperature of the mold, a movable mold temperature of the mold, and a first temperature difference between the fixed mold temperature and the movable mold temperature; If the first temperature difference is not equal to the first preset temperature difference, controlling the fixed mold temperature and the movable mold temperature to approach each other according to the PID controller so that the first temperature difference is equal to the first preset temperature difference; If the first temperature difference is equal to the first preset temperature difference, a larger temperature between the fixed mold temperature and the movable mold temperature is determined as the current temperature of the mold.

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