Accumulation prediction device in mold device and injection molding machine

Abstract

The present invention relates to a build-up prediction device in a mold device and an injection molding machine capable of simply inferring the adhesion amount of a build-up in a mold device. The injection molding machine (1) of the present invention, which has an injection device (11) that injects a molding material into a mold device (101), has a gas analysis section that analyzes generated gas from the injection device (11) and / or the mold device (101) and measures the generation amount of a material gas originating from the molding material, and a build-up inference section that infers the adhesion amount of a build-up in the mold device (101) based on material decomposition information related to the relationship between the generation amount of a nonvolatile component when the molding material is heated and the generation amount of a volatile component, from the generation amount of the material gas.

Description

Technical Field

[0001] This application claims priority based on Japanese Patent Application No. 2022-212438, filed on December 28, 2022. The entire contents of that Japanese application are incorporated herein by reference.

[0002] This invention relates to an accumulation prediction device for a mold assembly in an injection molding machine and to an injection molding machine, and particularly to a technique for inferring or predicting accumulations that may adhere to the mold assembly during injection molding. Background Technology

[0003] In injection molding using an injection molding machine, with the mold assembly installed on the injection molding machine, the injection device melts the molding material such as thermoplastic resin and injects it into the mold assembly, so that the molten molding material solidifies within the mold assembly.

[0004] When injection molding is repeatedly performed, the buildup primarily stems from the adhesion and accumulation of molding material components within the spaces and gaps of the mold assembly. This buildup, known as mold deposits, can lead to molding defects such as gas burning and inadequate filling of the molding material if injection molding continues in this state. Therefore, after a certain period of use, the injection molding machine needs to be cleaned for maintenance to remove the buildup.

[0005] Regarding the deposits within the mold assembly, Patent Document 1 discloses the following: "An injection molding machine comprising a process controller for controlling the cylinder temperature based on a set value, characterized in that the process controller comprises: an information collection unit for storing the intensity of volatile components of resin at each cylinder temperature; a mold deposit calculation unit for calculating the relationship between cylinder temperature and intensity of each volatile component based on the stored data, and for calculating a fitting curve of the intensity of the volatile component based on the calculated relationship between cylinder temperature and intensity of each volatile component; and a cylinder temperature processing unit for calculating the temperature at which the slope of the calculated fitting curve becomes a predetermined value α, and for setting the cylinder temperature based on that temperature."

[0006] Patent document 2 describes the following: "A mold part manufacturing apparatus that fills a mold cavity with molten resin and performs injection molding on the mold part, characterized in that it comprises: a detection mechanism for detecting a physical quantity of gas generated when filling the mold cavity with molten resin; a storage mechanism for storing the physical quantity detected by the detection mechanism at each molding shot; and a calculation mechanism for calculating the rate of change of the physical quantity stored by the storage mechanism at each molding shot, and determining the mold maintenance period based on the rate of change of the physical quantity."

[0007] Patent Document 1: Japanese Patent Application Publication No. 2008-194861

[0008] Patent Document 2: Japanese Patent Application Publication No. 2011-152766

[0009] Since the aforementioned deposits are generated inside the mold assembly, they are difficult to monitor from the outside, and frequent checks require significant time. Furthermore, the amount of deposits adhering to the mold assembly varies depending on the type of molding material, the shape of the mold assembly, and the molding conditions, making it difficult to determine when the mold assembly needs to be cleaned.

[0010] In this case, it is desirable to be able to easily infer the amount of buildup inside the mold assembly, thereby predicting when the mold assembly needs to be cleaned.

[0011] In Patent Document 1, the purpose of "setting the cylinder temperature to the optimal level" is to "reduce molding defects caused by mold deposits". It is difficult to say that the amount of deposits adhering to the mold device has been adequately studied.

[0012] Furthermore, even if, as described in Patent Document 2, the physical quantity of gas generated when filling the mold cavity with molten resin is detected, and the mold maintenance period is determined based on the rate of change of this physical quantity, it is sometimes impossible to effectively infer the amount of deposits. Summary of the Invention

[0013] The subject of this invention is to solve the problem of predicting the amount of buildup in a mold assembly and to provide an injection molding machine that can easily infer the amount of buildup in the mold assembly.

[0014] An accumulation prediction device capable of solving the above-mentioned problems is an injection molding machine equipped with an injection device for injecting molding material into a mold device, which predicts accumulation within the mold device and includes: a gas analysis unit that analyzes generated gases from the injection device and / or the mold device and measures the amount of material gas generated from the molding material; and an accumulation inference unit that infers the amount of accumulation adhering within the mold device based on material decomposition information related to the relationship between the amount of non-volatile components generated and the amount of volatile components generated when the molding material is heated, according to the amount of material gas generated.

[0015] Furthermore, the injection molding machine is equipped with the aforementioned buildup prediction device and injection device.

[0016] The effects of the invention

[0017] Based on the aforementioned accumulation prediction device, the amount of accumulation within the mold device can be easily inferred. Attached Figure Description

[0018] Figure 1 This is a cross-sectional view of an injection molding machine that can use an example of the buildup prediction device according to one embodiment of the present invention.

[0019] Figure 2 This is a block diagram illustrating an accumulation prediction device according to one embodiment of the present invention.

[0020] Figure 3 It is a schematic representation of the meaning of the word. Figure 2 An enlarged cross-sectional view of an example of how the gas collection section of a sediment prediction device captures and generates gas.

[0021] Figure 4 It is a schematic representation of the meaning of the word. Figure 2 An enlarged cross-sectional view of another example of how the gas trapping section of a sediment prediction device traps and generates gas.

[0022] Figure 5 This refers to the process of heating 1g of PBT1 at 280℃. Figure 5 (A) in the middle and when heated to 300°C ( Figure 5 A graph depicting the amount of non-volatile components and volatile components generated in (B) of the graph.

[0023] Figure 6 This refers to the process of heating 1g of PBT2 at 280℃. Figure 6 (A) in the middle and when heated to 300°C ( Figure 6 A graph depicting the amount of non-volatile components and volatile components generated in (B) of the graph.

[0024] Explanation of symbols

[0025] 1-Injection molding machine, 2-Base, 11-Injection unit, 12-Cylinder, 12a-Feed port, 12b-Nozzle, 12c-Water cooling cylinder, 13-Screw, 14-Heater, 15-Motor housing, 21-Moving device, 22-Hydraulic pump, 23-Pump working motor, 24-Hydraulic cylinder, 25-Sliding base, 26-Guide component, 31-Mold closing device, 32-Pressure plate, 32a-Fixed pressure plate, 32b-Movable pressure plate, 32c-Connecting rod, 32d-Guide component, 33-Pressure plate Operating mechanism, 34-rear pressure plate, 35-mold clamping motor, 36-motion conversion mechanism, 36a-lead screw shaft, 36b-nut, 37-toggle mechanism, 37a~37c-connecting rod, 37d-crosshead, 38-mold thickness adjustment motor, 41-ejection device, 42-ejection rod, 43-rod drive source, 51, 61-gas collection unit, 101-mold device, 102-fixed mold, 103-movable mold, 104-movable part, 105-vent, Gg-gas generation. Detailed Implementation

[0026] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0027] An embodiment of the present invention provides a deposit prediction device, for example, for use in... Figure 1 The illustrated injection molding machine 1 is expected to contain the buildup within the mold assembly 101 installed in the injection molding machine 1.

[0028] Figure 1 The injection molding machine 1 shown generally includes: an injection unit 11, which melts molding materials such as thermoplastic resin and injects them into a mold unit 101 by rotating and advancing a screw 13 disposed inside and heating it with a heater 14 disposed around it; a moving device 21, which moves the injection unit 11 forward and backward relative to the mold unit 101; a mold closing device 31, which opens and closes the mold unit 101 between a closed state and an open state; and an ejection device 41, which removes the molded article from the mold unit 101 in the open state.

[0029] In the example shown, the mold assembly 101 installed on the injection molding machine 1 includes a fixed mold 102 and a movable mold 103 that form a cavity on the inner side when the mold is closed, and movable parts such as an ejector pin that are displaced by an ejector device 41 to push out and remove the molded article. This mold assembly 101 is mainly divided into two parts, the fixed mold 102 and the movable mold 103, which can be called a two-plate mold, but it can also be further divided into three parts, such as a sliding mold, a sliding core, or a stripper plate, to become a three-plate mold. The mold assembly 101 is appropriately installed on the injection molding machine 1 according to the shape of the molded article to be manufactured and can be replaced; here, the mold assembly 101 is not considered part of the injection molding machine 1. The equipment or apparatus that includes the injection molding machine 1 and the mold assembly 101 installed on the injection molding machine 1 is sometimes called an injection molding system.

[0030] As described later, in the injection molding process using injection molding machine 1, the following mold closing process is performed: after the molding material has been measured in a specified amount and placed inside the injection device 11 in the previous metering process, the mold closing device 31 is used to close the mold device 101 and put it in the mold closing state.

[0031] Next, the following steps are performed in sequence: a filling step, in which the above-mentioned molding material is injected into the mold device 101 by advancing the screw 13, and the molding material is filled into the cavity in the mold device 101; and a pressure holding step, in which the screw 13 is advanced further and the molding material located inside the front end of the injection device 11 is held at a specified pressure.

[0032] Next, a cooling process is performed, in which the molding material filling the cavity of the mold device 101 is cooled and solidified to obtain a molded article. At this time, a metering process is performed, in which the molding material additionally fed into the injection device 11 is melted while being conveyed towards the front end of the injection device 11 by the rotation of the screw 13 under the heating of the heater 14, and a predetermined amount of molding material is filled into the front end.

[0033] Then, the removal process is carried out. In this removal process, the mold closing device 31 is activated to open the mold device 101 and put it in the open state. The movable part 104 is moved by the ejection device 41 and the molded product is unloaded from the mold device 101.

[0034] (Debris Prediction Device)

[0035] When injection molding is repeatedly performed as described above, deposits (so-called mold deposits) mainly arise from the components of the molding material adhering to the surface of the gaps and spaces within the mold assembly 101. These deposits not only hinder the smooth filling of the molding material into the mold assembly 101, resulting in poor molded product shape, but also block the vents, causing gas burning and other molding defects.

[0036] To prevent such molding defects, the injection molding machine 1 equipped with the mold device 101 needs to be cleaned to remove deposits after a certain period of use. However, until now, it has been difficult to control the degree of deposit adhesion, so it is impossible to clean the mold device 101 at the appropriate time. Sometimes, a large amount of deposits adhering to the mold device 101 is only noticed after a molding defect has occurred.

[0037] In this embodiment, the following method is used: Figure 2 The accumulation prediction device illustrated herein is used to predict the accumulation within the mold assembly 101. This accumulation prediction device includes: a gas analysis unit that analyzes the generated gases from the injection unit 11 and / or the mold assembly 101; and an accumulation inference unit connected to the gas analysis unit that infers the amount of accumulation within the mold assembly 101 based on the analysis results from the gas analysis unit. Furthermore, the accumulation inference unit may be included in a calculation unit that performs predetermined calculations.

[0038] More specifically, in the gas analysis unit, the generated gases discharged from the injection device 11 and / or the mold device 101 are analyzed, and the amount of material gas generated from the molding material is determined by this analysis. This allows for the determination of the extent to which material gas generated due to the thermal decomposition of the molding material is produced. The gas analysis unit can preferably use, for example, a gas chromatograph or a gas sensor.

[0039] Then, the deposit estimation unit receives information from the gas analysis unit regarding the amount of material gas generated as an analysis result, and infers the amount of deposits adhering within the mold assembly 101 based on this information. Here, it is important to use material decomposition information when estimating the amount of deposits adhering, which is related to the relationship between the amount of non-volatile components generated and the amount of volatile components generated when the molding material used in injection molding is heated.

[0040] Based on the material decomposition information, the amount of non-volatile components generated during the heating and molding of the material can be used to determine the amount of non-volatile components generated. The amount of volatile components generated corresponds to the amount of material gas generated from the injection unit 11 and / or the mold unit 101, and the amount of non-volatile components generated corresponds to the amount of deposits formed within the mold unit 101. Therefore, by using the material decomposition information in the deposit estimation section, the amount of deposits formed within the mold unit 101 can be effectively estimated. In this case, it is much simpler to perform the task compared to actually checking the interior of the mold unit 101 frequently.

[0041] like Figure 2 As shown, the buildup prediction device sometimes also includes an input section for allowing the user to input arbitrary or prescribed information and / or a storage section for storing information. These input sections and storage sections are connected to the calculation section. The aforementioned material decomposition information is used in the buildup prediction section by being pre-stored in the storage section and input by the user from the input section. Furthermore, material decomposition information can also be obtained from external sources via wireless or wired communication or storage devices and used in the buildup prediction section. For example, the aforementioned material decomposition information can also be obtained via the Internet through a buildup prediction device connected to the Internet as part of the Internet of Things (IoT) or through an injection molding machine 1 equipped with a buildup prediction device. Furthermore, the buildup prediction device sometimes further includes an output section that outputs the calculation results from the buildup prediction section and the cleaning determination section described later. In addition to the output section, or in place of the output section, a display section can be provided to visually display the calculation results.

[0042] Material decomposition information can be obtained, for example, by conducting additional heating experiments on the molding material used in injection molding. The material decomposition information may include experimental results regarding the heating experiment results for this molding material.

[0043] When conducting heating experiments on the molding material, the molding material can be heated to a temperature corresponding to the temperature of the molding material inside the mold device 101 when the injection device 11 is heated in injection molding, and in particular, to a temperature substantially equal to the temperature of the molding material inside the injection device 11 during that heating. The temperature at which the molding material is heated preferably includes the temperature of the molding material inside the injection device 11 when the injection device 11 is actually heated. That is, the heating temperature of the molding material in heating experiments, etc., preferably includes the temperature of the molding material inside the injection device 11 during injection molding. Specifically, this temperature (hereinafter also referred to as the "molding temperature") is sometimes set to a temperature range of 180°C or higher and 320°C or lower.

[0044] When a molding material is heated in a heating experiment, it decomposes to generate non-volatile and volatile components. By measuring the amount of each of these components generated, information about the material decomposition and its relationship to the amount of non-volatile and volatile components generated when the molding material is heated can be obtained.

[0045] The amount of non-volatile components generated from the molding material can be measured using a heating device. The molding material is placed inside a heating furnace of this device. Then, while introducing inert gases such as helium (He), argon (Ar), or nitrogen (N2) into the path connected to the heating furnace, the molding material is heated to the aforementioned molding temperature. A collecting component is installed near the outlet of the gas flowing through the heating furnace, and this collecting component collects the non-volatile components exiting from the outlet of the heating furnace. The mass of the non-volatile components collected by the collecting component is then determined. Furthermore, for example, a plate-shaped collecting component can preferably be made of any material such as glass, metal, or ceramic.

[0046] Furthermore, the amount of volatile components generated from the molding material can be measured using a heating device. In this heating device, after the molding material is placed in a heating furnace, the path connected to the heating furnace is evacuated, and then an inert gas is introduced into the path at a predetermined pressure, thereby heating the molding material in the heating furnace to the aforementioned molding temperature. A portion of the volatile components generated and flowing within the path is sampled and quantitatively analyzed using a gas chromatograph.

[0047] For example, as a molding material, ester-based polymer material PBT, when heated, has its main chain broken due to thermal decomposition, generating precipitates such as terephthalic acid and oligomers as non-volatile components (high-boiling-point components), and volatile components containing linear or branched saturated or unsaturated hydrocarbons. The volatile components are sometimes, for example, composed of C n H 2n+2 Alkanes represented by (n≥1), and those derived from C n H 2n Alkenes represented by (n≥2), and those derived from C n H 2n-2 (n≥2) represents alkynes or dienes, etc. Additionally, hydrocarbons with 2 carbon atoms, such as ethylene, ethane, and acetylene, are collectively referred to as C2; hydrocarbons with 3 carbon atoms, such as propane, propylene, propyne, propadiene, cyclopropane, and cyclopropene, are collectively referred to as C3; hydrocarbons with 4 carbon atoms, such as n-butane, isobutane, 1-butene, 2-butene, 1,3-butadiene, 1,2-butadiene, cyclobutane, cyclobutene, and cyclobutadiene, are collectively referred to as C4; and hydrocarbons with 4 carbon atoms, such as n-pentane, 2-methylbutane, 2,2-dimethylpropane, 1-pentene, 2-pentene, 2-methyl-1-butene, and 3-methyl... Hydrocarbons with 5 carbon atoms, such as -1-butene, 2-methyl-2-butene, 1-pentyne, and 2-pentyne, are collectively referred to as C5 hydrocarbons. Hydrocarbons with 6 carbon atoms, such as n-hexane, 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane, 2,3-dimethylbutane, 1-hexene, 2-hexene, 2-methyl-1-pentene, 3-methyl-1-pentene, 2-methyl-2-pentene, 3-methyl-2-pentene, 1-hexyne, 2-hexyne, cyclohexane, 1-cyclohexenyl, and 1-cyclohexyne, are collectively referred to as C6 hydrocarbons. A good linear relationship was observed between the amount of non-volatile components and the amount of volatile components generated. Therefore, if the amount of volatile components generated when the molding material is heated to the molding temperature is known, the amount of non-volatile components that cause mold deposits can be deduced.

[0048] Furthermore, as a molding material capable of quantifying the amount of non-volatile and volatile components generated through heating experiments and obtaining material decomposition information, polyester-based polymers, polyamide-based polymers, polyolefin-based polymers, acrylonitrile-butadiene-styrene copolymers, polycarbonate resins, polyphenylene sulfide resins, and acrylic resins are preferred, with polyester-based polymers and polyamide-based polymers being more preferred, and polyester-based polymers being the most preferred.

[0049] In polyester-based polymer materials, polyethylene terephthalate, polypropylene terephthalate, and polybutylene terephthalate (PBT) are preferred. Furthermore, these resins can be used alone or as a mixture of various resins. They can also contain different types of monomer units, similar to copolymers.

[0050] The temperature inside the heating furnace of the heating device is preferably above 180°C and below 320°C, more preferably above 250°C and below 310°C, and most preferably above 280°C and below 300°C. This is because when the temperature inside the heating furnace is set below 180°C, the molding material does not melt sufficiently, and the amount of volatile or non-volatile components generated is also less, so the accuracy of material decomposition information may decrease. In addition, at temperatures above 320°C, the thermal decomposition of the molding material becomes significant, and it may be difficult to quantify the non-volatile components.

[0051] Since the non-volatile components can be considered to adhere to the mold device 101 as deposits, the amount of non-volatile components generated corresponds substantially to or is consistent with the amount of deposits. If the deposit inference unit makes this inference, the accuracy of inferring the amount of deposits adhering to the mold device 101 will be greatly improved.

[0052] Furthermore, the correlation coefficient between the amount of non-volatile components generated and the amount of volatile components generated when the molding material is heated is preferably 0.7 or higher, more preferably 0.9 or higher. The material decomposition information can include correlation information related to this correlation.

[0053] Furthermore, when the material decomposition information is known or can be obtained externally, additional heating experiments as described above can sometimes be omitted. Moreover, material decomposition information for multiple molding materials can be stored, for example, in a storage unit and used in the buildup prediction unit, depending on the type of molding material. Furthermore, it is possible to consider using other machine learning methods, such as deep learning, to learn from known material decomposition information and the actual buildup adhesion amount, thereby further improving the accuracy of the material decomposition information. This is easily achieved by connecting the buildup prediction device to the Internet as described above. This improves the user experience when using the injection molding machine 1 and is expected to contribute to digital transformation (DX).

[0054] Among them, such as Figure 2 As shown, the accumulation prediction device sometimes also has a gas collection unit connected to the gas analysis unit to collect the generated gas from the injection device 11 and / or the mold device 101. Figure 3 and / or Figure 4 As shown, the gas collection unit can be configured in the injection molding machine 1, but it is not limited to the configuration of the gas collection unit shown in the figure, as long as it can capture the generated gas.

[0055] Figure 3 The gas trapping unit 51 shown is at least partially cylindrical and is capable of trapping the generated gas Gg discharged through the vent 105 provided within the mold assembly 101. The vent 105, also referred to as a gas outlet, is provided in the mold assembly 101 to discharge gases such as air ejected during the filling of the molded material into the cavity within the mold assembly 101. The generated gas Gg generated during injection molding is discharged from the vent 105 along with air, and may contain a large portion of the material gases originating from the molded material. Therefore, by trapping the generated gas Gg from the vent 105 and performing analysis based on the gas analysis unit and inference based on the deposit inference unit as described above, the accuracy of the deposit adhesion amount inference can be significantly improved.

[0056] Furthermore, the gas collection unit 51 can also be moved automatically or manually. For example, when collecting gas Gg, such as... Figure 3 As indicated by the blank arrow, the gas trapping unit 51 is moved to approach and connect with the hole that communicates with the exhaust port 105 of the mold device 101. Furthermore, after capturing the generated gas Gg, the gas trapping unit 51 can be moved away from the mold device 101.

[0057] exist Figure 4 In this configuration, a cylindrical gas collecting section 61 is positioned near the nozzle 12b to collect the generated gas Gg discharged from the front end of the nozzle 12b of the injection device 11. For example... Figure 4 As indicated by the black arrow, when the injection device 11 is moved backward toward the cylinder 12 away from the mold device 101 by the moving device 21 described later, as indicated by the blank arrow, the gas trapping section 61 can approach the nozzle 12b of the cylinder 12 and trap the generated gas discharged from its front end.

[0058] pass Figure 4 The timing of gas collection by the gas collection unit 61 is not particularly limited, but it can be set, for example, for a cleaning operation in which the molding material stored at the front end of the cylinder 12 is discharged from the nozzle 12b by the advance of the screw 13 for purposes such as replacing the molding material used in injection molding with another molding material. When with Figure 3 Compared to the gas trapping unit 51, the gas trapping unit 61 has the advantage of being able to be used regardless of the shape of the mold device 101.

[0059] The accumulation prediction device may also have a cleaning determination unit, which determines whether the mold device 101 needs to be cleaned based on the amount of accumulation inferred by the accumulation prediction unit.

[0060] In the cleaning determination unit, for example, it determines whether the amount of deposited material adhering to the material inference unit is above or above a predetermined reference value. Then, if the amount of deposited material is below the reference value, it is determined that the mold device 101 does not need to be cleaned, and no action is taken or a message indicating that cleaning is not required is output from the output unit. Alternatively, if the amount of deposited material is above the reference value, a message indicating that the mold device 101 needs to be cleaned can be output to the user through the output unit. Thus, the user can recognize that the deposited material has adhered to the mold device 101 to the extent that it needs to be cleaned, and the user is urged to clean it.

[0061] Furthermore, the cleaning determination unit can use the estimation results of the amount of deposits attached in the deposit estimation unit to determine the maintenance cycle of the mold device 101.

[0062] The aforementioned buildup prediction device can be configured as a device different from the injection molding machine 1, or it can be configured as a device included in the injection molding machine 1. When the injection molding machine 1 is equipped with a buildup prediction device, the calculation unit (buildup estimation unit and cleaning determination unit) of the buildup prediction device can be included in the control unit of the control device that controls the operation of the injection molding machine 1. Furthermore, the input unit, storage unit, and output unit of the buildup prediction device are sometimes interchangeable with the control device of the injection molding machine.

[0063] (Injection device)

[0064] The injection unit 11 mainly comprises a cylindrical cylinder 12 extending toward the mold assembly 101, a screw 13 arranged parallel to its central axis inside the cylinder 12 and with spiral threads around it, a heater 14 of the strip shape or the like surrounding the cylinder 12 on its outer periphery, and a motor housing 15 arranged behind the cylinder 12 and the screw 13. Although not shown in the figure, the motor housing 15 is equipped with: a metering motor that rotates the screw 13 around its central axis to store a specified amount of molding material at the front end of the cylinder 12, an injection motor that moves the screw 13 forward and backward in directions toward and away from the mold assembly 101, and a pressure sensor that detects the pressure exerted on the screw 13 by the molding material.

[0065] Furthermore, here, the orientation of the fixing platen 32a of the mold clamping device 31, which is close to the fixed mold 102 on which the mold device 101 is mounted, is set to the front side, and the orientation away from the fixing platen 32a is set to the rear side. Therefore, when in Figure 1 When observing the injection device 11 located to the right of the fixed pressure plate 32a, the left side closer to the fixed pressure plate 32a is called the front side, and the right side farther away from the fixed pressure plate 32a is called the rear side.

[0066] The cylinder body 12 has a supply port 12a located on its rear side and near the front of the motor housing 15, which is capable of housing a hopper for feeding molding material into the cylinder body 12. Furthermore, a nozzle 12b with a smaller cross-sectional area is provided at the front end of the cylinder body 12 near the mold assembly 101. Additionally, a water-cooling cylinder 12c, based on water cooling or the like, can be provided near the supply port 12a.

[0067] For example, as shown in the figure, the heater 14 arranged around the cylinder 12, including the area around the nozzle 12b, is divided into multiple sections along the cylinder axial direction, enabling the heater section to heat the interior of the cylinder 12 at different temperatures. A temperature detector can be installed in each heater section.

[0068] Although not illustrated, sometimes a check ring is arranged around a contraction section, where the outer diameter of the screw 13 is locally reduced, on the front end side of the screw 13. This check ring moves forward and backward with the screw 13 to prevent molding material fed to the front side from flowing back to the rear side. This check ring, for example, moves back and forth relative to the screw 13 based on the pressure exerted on the molding material located on its front or rear side, thereby allowing only the flow of molding material from the rear side towards the front side.

[0069] According to the injection device 11 with this structure, in the metering process, the molding material fed into the cylinder 12 from the supply port 12a is heated by the heater 14 on the outer periphery of the cylinder 12 and melted by the rotation of the screw 13 driven by the metering motor. Simultaneously, it is fed forward and stored at the front end of the cylinder 12. At this time, the screw 13 is displaced backward by the injection motor, forming a space for storing the molding material at the front end of the cylinder 12. Furthermore, as described above, this metering process can be performed simultaneously with the cooling process of the previous molding.

[0070] Then, in the filling process, by advancing the screw 13, the molding material at the front end of the cylinder 12 is injected into the mold assembly 101 through the nozzle 12b. Furthermore, in the subsequent pressure holding process, pressure is applied to the molding material filled into the cavity of the mold assembly 101 by the molding material remaining in the front end of the cylinder 12. At this time, any insufficient molding material in the cavity of the mold assembly 101 due to cooling and shrinkage is replenished.

[0071] In addition, the injection molding machine 1 is an inline screw type, but it can also be a screw pre-plastic injection molding machine that is divided into a plasticizing cylinder and a plasticizing screw and an injection cylinder and an injection plunger in terms of structure and function.

[0072] (Mobile device)

[0073] The moving device 21 is, for example, a forward and backward drive mechanism provided in the lower part of the motor housing 15 of the injection device 11, which moves the injection device 11 forward and backward relative to the fixed pressure plate 32a.

[0074] Various mechanisms can be used as the forward and backward drive mechanism constituting the moving device 21. The moving device 21 shown in the figure is configured to include a hydraulic pump 22 such as a hydraulic pump, a pump working motor 23 based on electric motor or the like to operate the hydraulic pump 22, and a double-acting hydraulic cylinder 24 that pushes out and pulls in a piston rod whose front end is fixed on a fixed pressure plate 32a by supplying working fluid from the hydraulic pump 22.

[0075] The mobile device 21 also includes a sliding base 25 on which the aforementioned hydraulic pump 22, pump motor 23, and hydraulic cylinder 24 are mounted, and a guide member 26 laid on the base 2 and guiding the linear movement of the sliding base 25. This enables the injection device 11 mounted on the upper part of the sliding base 25 to move forward and backward.

[0076] By moving the injection device 11 away from or close to the mold device 101 using the moving device 21, the nozzle 12b of the cylinder 12 of the injection device 11 can be pressed against the mold device 101 at a specified pressure, i.e., so-called nozzle contact is achieved.

[0077] (Mold closing device)

[0078] The mold closing device 31 moves the movable mold 103 relative to the fixed mold 102 of the mold device 101 to open and close the mold device 101, so that the mold device 101 is in a closed state, a closed state, or an open state. The mold closing device 31 has a pressure plate 32 including a fixed pressure plate 32a, a movable pressure plate 32b, and a connecting rod 32c, and a pressure plate operating mechanism 33 for operating the pressure plate 32.

[0079] In the pressure plate 32, as described above, the fixed pressure plate 32a is fixed and installed on the pressure plate mounting plate of the base 2. On the other hand, the movable pressure plate 32b is disposed on the guide member 32d laid on the guide plate of the base 2, and can slide in the direction of separation from and approach of the fixed pressure plate 32a.

[0080] The pressure plate operating mechanism 33 includes a rear pressure plate 34 disposed on the base 2, a mold clamping motor 35 disposed on the rear pressure plate 34, a motion conversion mechanism 36 that converts the rotational motion of the mold clamping motor 35 into linear motion in the displacement direction of the movable pressure plate 32b, and an elbow mechanism 37 that increases the force transmitted to the motion conversion mechanism 36 and transmits it to the movable pressure plate 32b.

[0081] The motion conversion mechanism 36 can be configured to convert rotary motion into linear motion in various ways. In this example, it includes a lead screw 36a driven by a mold clamping motor 35 and a nut 36b screwed into the lead screw 36a. Alternatively, the motion conversion mechanism 36 can be a ball screw.

[0082] Then, the toggle mechanism 37, which increases the transmitted force from the motion conversion mechanism 36, is a mechanism in which multiple connecting rods 37a to 37c that connect the rear pressure plate 34 and the nut 36b to the movable pressure plate 32b are oscillatingly connected by a joint.

[0083] The number and shape of the connecting rods and joints can be changed appropriately. Figure 1In the middle, on the crosshead 37d that is connected to the nut 36b and extends in the vertical direction, there is a pair of connecting rods consisting of connecting rods 37a to 37c that are positioned vertically and vertically across the crosshead 37d.

[0084] In addition, a mold thickness adjustment motor 38 can be installed on the rear pressure plate 34, in addition to the aforementioned mold clamping motor 35. This mold thickness adjustment motor 38 provides rotational driving force to the lead screw shaft and nut connected to the extensions of the connecting rods 32c of the pressure plate 32, thereby functioning to adjust the gap between the fixed pressure plate 32a and the rear pressure plate 34, which is movably mounted on the base 2. Therefore, when the mold assembly 101 is replaced, or when the thickness of the mold assembly 101 changes due to temperature variations, the mold thickness can be adjusted to provide the desired clamping force to the mold assembly 101. Although not shown in the figure, mold thickness adjustment can be achieved even if the fixed pressure plate side is movable on the base 2 while the rear pressure plate side is fixed.

[0085] The mold clamping device 31 shown in the figure is a horizontal device in which the moving direction of the movable pressure plate 32b is parallel to the horizontal direction, but it can also be a vertical device in which the moving direction is set to the vertical direction.

[0086] (Ejection device)

[0087] The ejection device 41 provided on the movable pressure plate 32b includes: an ejection rod 42 that passes through the movable pressure plate 32b and extends therethrough, and is driven to move forward and backward by pushing the ejection pin and other movable parts 104 of the mold device 101 from the rear side; and a rod drive source 43, such as a motion conversion mechanism including a motor and a ball screw, so as to make the ejection rod 42 work.

[0088] The ejector device 41 allows the ejector rod 42, driven by the rod drive source 43, to advance during the removal process of the molded article, and the movable part 104 to protrude within the mold device 101, thereby ejecting the molded article from the mold device 101. Furthermore, after the movable part 104 protrudes, the ejector rod 42 can be retracted by the rod drive source 43 and returned to its original position.

[0089]

Example

[0090] Next, tests were conducted related to the implementation of the accumulation prediction device of the present invention, and therefore will be described below. However, the description herein is for simple illustrative purposes only and is not intended to be limited thereto.

[0091] (Experimental Example 1)

[0092] As an example, Figure 5 (A) and Figure 5Section (B) shows material breakdown information when using commercially available PBT (Sigma-Aldrich, product number: 190942) (referred to as "PBT1") as a molding material.

[0093] Figure 5 (A) in the figure depicts the amounts of non-volatile components generated when 1 g of PBT1 is heated at 280°C using a heating device, and the amounts of volatile components generated when 1 g of PBT1 is heated at 280°C using a heating device. Furthermore, Figure 5 (B) is a graph depicting the amount of non-volatile components generated when 1g of PBT1 is heated at 300°C using a heating device and the amount of volatile components generated when 1g of PBT1 is heated at 300°C using a heating device.

[0094] from Figure 5 It is clearly known that in PBT1, there is a strong positive correlation between the amount of non-volatile components generated and the amount of volatile components generated. Therefore, when the molding material used for injection molding is PBT1, if the amount of material gas generated from the injection unit and / or mold unit is defined as the amount of volatile components generated, the amount of non-volatile components generated can be approximately uniquely determined based on the amount of material gas generated.

[0095] (Experimental Example 2)

[0096] As another example, Figure 6 (A) and Figure 6 Section (B) shows material breakdown information when using PBT (Polyplastics, product number: DURANEX2000) (referred to as "PBT2") manufactured by a different manufacturer than PBT1 as a molding material.

[0097] Figure 6 (A) in the figure depicts the amounts of non-volatile components generated when 1 g of PBT2 is heated at 280°C using a heating device, and the amounts of volatile components generated when 1 g of PBT2 is heated at 280°C using a heating device. Furthermore, Figure 6 (B) in the figure depicts the amount of non-volatile components generated when 1g of PBT2 is heated at 300°C using a heating device and the amount of volatile components generated when 1g of PBT2 is heated at 300°C using a heating device.

[0098] from Figure 6It is clearly known that there is a strong positive correlation between the amount of non-volatile components generated and the amount of volatile components generated in PBT2. Therefore, when PBT2 is used as the molding material for injection molding, if the amount of material gas generated from the injection unit 11 and / or the mold unit 101 is set as the amount of volatile components generated, the amount of non-volatile components generated can be approximately uniquely determined based on the amount of material gas generated.

[0099] Therefore, according to the present invention, it is possible to simply and effectively infer the amount of deposits adhering within a mold device.

Claims

1. An accumulation prediction device for an injection molding machine having an injection device for injecting molding material into a mold device, predicting accumulation within the mold device, comprising: The gas analysis unit analyzes the gases generated from the injection unit and / or mold unit, and measures the amount of material gases generated from the molding material; and The deposit inference unit infers the amount of deposits adhering to the mold device based on material decomposition information related to the relationship between the amount of non-volatile components generated and the amount of volatile components generated when the molding material is heated, according to the amount of gas generated from the material.

2. The accumulation prediction device according to claim 1, further comprising: The gas collection unit collects the generated gases from the injection unit and / or the mold unit.

3. The accumulation prediction device according to claim 2, wherein, The gas trapping unit is capable of trapping the generated gas discharged from the exhaust port provided on the mold device.

4. The accumulation prediction device according to claim 2, wherein, The gas trapping section is capable of trapping the generated gas discharged from the front end of the nozzle of the injection device.

5. The accumulation prediction device according to claim 1, wherein, The material gas and the volatile components respectively contain linear or branched saturated or unsaturated hydrocarbons.

6. The accumulation prediction device according to claim 5, wherein, The material gas and the volatile components respectively contain hydrocarbons of C1 to C6.

7. The accumulation prediction device according to claim 5, wherein, The material gas and the volatile components comprise the C4 hydrocarbon.

8. The accumulation prediction device according to claim 5, wherein, The material gas and the volatile components contain 1,3-butadiene.

9. The accumulation prediction device according to claim 1, wherein, There is a correlation coefficient of over 0.7 between the amount of non-volatile components generated and the amount of volatile components generated when the molding material is heated. The material decomposition information includes correlation information regarding this correlation.

10. The accumulation prediction device according to claim 1, wherein, The material decomposition information includes experimental results related to the heating test results of the molded material.

11. The accumulation prediction device according to claim 1, wherein, The temperature at which the molding material is heated is above 180°C and below 320°C.

12. The accumulation prediction device according to claim 1, wherein, The temperature at which the molding material is heated includes the temperature of the molding material within the mold assembly when the injection device is heated.

13. The accumulation prediction device according to claim 1, further comprising: The cleaning determination unit determines whether the mold cleaning device needs to be cleaned based on the amount of deposits inferred by the deposit inference unit.

14. An injection molding machine comprising the buildup prediction device and injection device as described in any one of claims 1 to 13.

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