JP2023176960A - Injection molding device - Google Patents

Abstract

To provide an injection molding device capable of determining whether or not a gate is clogged with high accuracy.SOLUTION: An injection molding device 1 includes: an injection device 20 provided with a nozzle 24 that discharges a molten resin; a metal mold 30 provided with a molded product cavity C and a resin channel P; in-mold resin pressure acquiring devices 331 to 334 that detect an in-mold resin pressure being the pressure of resin material in the molded product cavity C or the resin channel P; a discharge pressure acquiring device 27 for acquiring a discharge pressure of the molten resin discharged from the nozzle 24; and a determining unit 61 for determining whether or not a resin is clogged in the resin channel P by calculating a characteristic quantity based on the in-mold resin pressure acquired by the in-mold resin pressure acquiring devices 331 to 334 and a discharge pressure acquired by the discharge pressure acquiring device. The resin channel P includes: a plurality of gates P31-P34; a plurality of runners P2; and spools P1, wherein the in-mold resin pressure acquiring devices 331-334 are provided at positions near each of the plurality of gates P31-P34.SELECTED DRAWING: Figure 2

Description

The present invention relates to an injection molding apparatus.

Patent Document 1 describes that in an injection molding apparatus, a sensor is installed in the injection device or the mold, and the quality of the molded product is estimated by machine learning using detection data from the sensor.

Japanese Patent Application Publication No. 2020-49929

By the way, the mold used for injection molding has a molded product cavity as a part where the molded product is molded, and a resin flow path (runner, spool (also known as sprue) between the molded product cavity and the part that comes into contact with the nozzle of the injection device). gate). For example, a problem may occur in which the gate in the resin flow path is temporarily clogged due to cold slag or foreign matter. If the gate is clogged, the molten resin will not flow from the resin flow path to the molded product cavity, which may cause a decrease in the dimensional accuracy of the molded product or destabilization of the dimensional accuracy.

When a molding cycle for molding a molded article is continuously executed a plurality of times, the gate may become temporarily clogged, and then the gate may become clogged. In addition, when molten resin is being supplied to the molded product cavity during molding of a single molded product, clogging at the gate may occur temporarily, and the clogging at the gate may then be resolved during molding of the molded product. be. In this way, the clogging in the gate does not only occur continuously over a long period of time, but also may occur temporarily, and it may not be easy to detect it. Further, it is difficult to determine whether there is clogging in the resin flow path or the molded product cavity from logging data such as the injection pressure of molten resin in the injection device.

The present invention has been made in view of this background, and it is an object of the present invention to provide an injection molding apparatus that can highly accurately determine whether or not a gate is clogged.

One aspect of the present invention includes an injection device including a nozzle that discharges molten resin;
A mold including a molded product cavity and a resin flow path that allows molten resin discharged from the nozzle to flow into the molded product cavity;
an in-mold resin pressure acquisition device that detects in-mold resin pressure that is the pressure of the resin material in the molded product cavity or in the resin flow path;
a discharge pressure acquisition device that acquires the discharge pressure of the molten resin discharged from the nozzle;
A feature quantity is calculated based on the above-mentioned in-mold resin pressure acquired by the above-mentioned in-mold resin pressure acquisition device and the above-mentioned discharge pressure acquired by the above-mentioned discharge pressure acquisition device. a determination unit that determines whether or not there is resin clogging in the resin flow path;
Equipped with
The resin flow path includes a plurality of gates connected to the molded product cavity, a plurality of runners respectively connected to the plurality of gates, and a spool connected to the plurality of runners and the nozzle,
The in-mold resin pressure acquisition device is provided in an injection molding device provided near each of the plurality of gates in the mold.

During molding of a molded product, molten resin is supplied from an injection device to a resin flow path of a mold, and is supplied from the resin flow path to a molded product cavity. If the gate in the resin flow path of the mold is clogged during molding, the molten resin will not flow from the resin flow path to the molded product cavity, or will be difficult to flow. Resin pressure in the mold fluctuates when a gate is clogged, but if there are multiple gates, detecting fluctuations in the resin pressure in the mold at a position near each gate makes it easier to determine whether each gate is clogged. Can be detected accurately.

In the above injection molding apparatus, the in-mold resin pressure acquisition device acquires the in-mold resin pressure at a position near each gate, and the discharge pressure acquisition unit acquires the discharge pressure discharged from the nozzle of the injection device. Based on the feature amounts calculated based on these, it is determined whether each gate is clogged. As a result, it is possible to more accurately determine whether each gate is clogged, so that it is possible to detect a decrease in the dimensional accuracy of the molded product, and it is possible to stabilize the dimensional accuracy.

As described above, according to the above aspect, it is possible to provide an injection molding apparatus that can highly accurately determine whether or not the gate is clogged.

1 is a diagram showing a mechanical configuration of an injection molding apparatus in Embodiment 1. FIG. FIG. 2 is an enlarged sectional view of the mold in FIG. 1 in Embodiment 1. 2 is a diagram showing the space part of the mold (molded product cavity and resin flow path) and the resin pressure acquisition part in the mold in Embodiment 1, and is a transparent view seen from the axial direction of the spool (as seen from the right of FIG. 2). figure). 1 is a flowchart showing an injection molding method in Embodiment 1. (a) A graph showing pressure changes in the injection process, pressure holding process, and cooling process when no gate clogging occurs, (b) An enlarged view of the area surrounded by the two-dot chain line P in (a). (a) A graph showing pressure changes in the injection process, pressure holding process, and cooling process when gate clogging occurs; (b) An enlarged view of the area surrounded by the two-dot chain line P in (a). 1 is a functional block diagram showing an injection molding apparatus of Embodiment 1. FIG. FIG. 2 is a functional block diagram showing processing of a computer device for determining gate clogging that constitutes the injection molding apparatus of the first embodiment. FIG. 3 is a diagram illustrating a feature amount map and determination criteria stored in a storage unit in the first embodiment. FIG. 7 is a diagram illustrating a space portion of a mold (a molded product cavity and a resin flow path) and an in-mold resin pressure acquisition unit in Embodiment 2, and is a transparent view seen from the axial direction of the spool. FIG. 3 is a functional block diagram showing an injection molding apparatus in Embodiment 3.

[Embodiment 1]
(1. Configuration of injection molding device 1)
An injection molding apparatus 1 in Embodiment 1 will be described with reference to FIG. 1. The injection molding apparatus 1 is an apparatus for molding a resin molded product using a mold 30. The injection molding apparatus 1 mainly includes a bed 10, an injection device 20, a mold 30, a mold clamping device 40, a control device 50, and a computer device 60 for determining gate clogging. The bed 10 is a member installed on an installation surface.

The injection device 20 is placed on the bed 10. The injection device 20 is a device that melts resin as a molding material, applies pressure to the molten resin, and supplies it to the molded product cavity C of the mold 30. The injection device 20 includes a hopper 21, a cylinder 22, a screw 23, a nozzle 24, a heater 25, a drive device 26, and a discharge pressure acquisition device 27.

The hopper 21 is an input port for resin pellets (granular molding material) that are the raw material of the molding material. The cylinder 22 stores molten resin produced by heating and melting the pellets input into the hopper 21 . Further, the cylinder 22 is provided so as to be movable in the axial direction of the cylinder 22 with respect to the bed 10. The screw 23 is arranged inside the cylinder 22 and is provided so as to be rotatable and movable in the axial direction. The nozzle 24 is a discharge port provided at the front end of the cylinder 22 and discharges the molten resin inside the cylinder 22 as the screw 23 moves forward.

The heater 25 is, for example, provided on the outer circumferential surface of the cylinder 22 or embedded inside the cylinder 22 to heat the resin inside the cylinder 22 . That is, the heater 25 melts the pellets and maintains the molten resin in a molten state. The drive device 26 moves the cylinder 22 in the axial direction (forward and backward), rotates the screw 23 and moves the screw 23 in the axial direction (forward and backward), and the like.

The discharge pressure acquisition device 27 is provided, for example, near the base end of the screw 23, and acquires the discharge pressure that is pressure data that the screw 23 receives from the molten resin in the cylinder 22.

In addition to the discharge pressure acquisition device 27, the injection device 20 includes sensors that acquire the position of the cylinder 22, the position of the screw 23, the moving speed of the screw 23, the temperature of the heater 25, the state of the drive device 26, and the like.

The mold 30 includes a first mold 31 that is a fixed side and a second mold 32 that is a movable side. The mold 30 forms a molded product cavity C between the first mold 31 and the second mold 32 by clamping the first mold 31 and the second mold 32 together. The first mold 31 and the second mold 32 include a resin flow path P between the molded product cavity C and a portion that abuts the nozzle 24 of the injection device 20 . The resin flow path P serves as a flow path for guiding the molten material supplied from the nozzle 24 of the injection device 20 to the molded product cavity C, and includes a spool P1, a runner P2, and a gate P3.

Furthermore, the mold 30 includes an in-mold resin pressure acquisition device 33 that detects in-mold pressure data that is the pressure of the resin material in the molded product cavity C or in the resin flow path P. The mold internal pressure data is pressure data that the inner wall surface of the molded product cavity C or the resin flow path P receives from the molten resin flowing inside the mold 30.

The mold clamping device 40 is arranged on the bed 10 to face the injection device 20. The mold clamping device 40 opens and closes the installed mold 30, and prevents the mold 30 from opening due to the pressure of the molten material injected into the molded product cavity C when the mold 30 is clamped. .

The mold clamping device 40 includes a fixed platen 41, a movable platen 42, a diver 43, a driving device 44, and a measuring device 45 for the mold clamping device. The first mold 31 is fixed to the fixed platen 41. The second mold 32 is fixed to the movable platen 42. The movable platen 42 can approach and move away from the fixed platen 41. Diver 43 supports movement of movable platen 42. The drive device 44 is configured by, for example, a cylinder device, and moves the movable platen 42. The mold clamping device measuring device 45 acquires the mold clamping force, the mold temperature, the state of the drive device 44, and the like.

The control device 50 controls the drive device 26 of the injection device 20 and the drive device 44 of the mold clamping device 40. The computer device 60 for determining gate clogging determines whether each gate P3 (shown in FIG. 2) in the resin flow path P of the mold 30 is clogged. The computer device 60 for determining gate clogging is comprised of an arithmetic device, a storage device, etc., and processes by executing a computer program. The computer device 60 for determining gate clogging uses, for example, control data from the control device 50, pressure data acquired by the discharge pressure acquisition device 27, in-mold resin pressure acquisition device 33, etc., to determine if each gate P3 is clogged. Determine the presence or absence of.

(2. Detailed configuration of mold 30)
The detailed configuration of the mold 30 will be explained with reference to FIGS. 2 and 3. The mold 30 has a molded product cavity C for molding a molded product. The molded product cavity C is formed by a first mold 31 and a second mold 32. In this embodiment, the molded product cavity C is formed, for example, in an annular shape, but it can be formed in any shape such as a C-shape or a U-shape. The molded product cavity C may be formed at only one location, or may be formed at a plurality of locations. In FIGS. 2 and 3, one molded product cavity C is illustrated for ease of explanation.

The mold 30 also has a resin flow path P that connects the molded product cavity C with a portion that contacts the nozzle 24 (shown in FIG. 1). The resin flow path P includes a spool P1 (also referred to as a sprue), a runner P2, and a gate P3. Spool P1 is a passage through which molten material is introduced from nozzle 24. The spool P1 is, for example, formed in a straight line from a contact portion with the nozzle 24.

The runner P2 is a flow path formed at an angle from the spool P1. That is, the molten resin introduced into the spool P1 flows into the runner P2. For example, as shown in FIG. 3, in this embodiment, a plurality of runners P2 are formed by branching in the radial direction from the spool P1 toward one molded product cavity C. Note that even when a plurality of molded product cavities C are formed, a plurality of runners P2 are formed by branching from the spool P1 toward each of the plurality of molded product cavities C.

The gate P3 is located at the tip of the runner P2 and is connected to the molded product cavity C, and is a flow path that guides the molten resin from the runner P2 to the molded product cavity C. The cross-sectional area of the flow path of the gate P3 is smaller than the cross-sectional area of the flow path of the runner P2. A plurality of gates P3 are formed to connect each of the plurality of runners P2 and one molded product cavity C. Therefore, even if one of the plurality of gates P3 is clogged, the molten resin flows into the molded product cavity C from the other gate P3. Although the number of runners P2 and gates P3 is not limited, in this embodiment, as shown in FIG. 3, four runners P2 and four gates P3 are each formed. The four gates P3 (P31 to P34) are arranged at equal intervals in the circumferential direction with the center of the spool P1 as a reference when viewed from the axial direction of the spool P1.

The mold 30 is provided with an in-mold resin pressure acquisition device 33, as shown in FIGS. 2 and 3. The in-mold resin pressure acquisition device 33 is provided at a position near each of the plurality of gates P3. In this embodiment, four in-mold resin pressure acquisition devices 331 to 334 are provided. As shown in FIG. 3, the position near each gate P3 is a position closer to one gate P3 than the center position P4 of gates P3 adjacent to each other in the arrangement direction. That is, the in-mold resin pressure acquisition device 33 is provided at a position corresponding to the plurality of gates P3. Each of the plurality of in-mold resin pressure acquisition devices 33 is provided in a range affected by clogging in the corresponding gate P3. Furthermore, in this embodiment, as shown in FIG. 2, the in-mold resin pressure acquisition device 33 is provided in the flat part C1 of the molded product cavity C. The in-mold resin pressure acquisition device 33 acquires the pressure of the molten resin within the mold 30.

(3. Injection molding method)
A method of injection molding a molded article using the injection molding apparatus 1 will be described with reference to FIG. 4. The injection molding method is executed by the control device 50 of the injection molding apparatus 1.

First, before a plurality of consecutive molding cycles, the control device 50 executes a purge step S1 in which the molten resin in the cylinder 22 is discharged from the nozzle 24 while the nozzle 24 is separated from the mold 30. The purge step S1 is performed, for example, for the purpose of discharging thermally degraded resin or replacing it with a different resin material. In the purge step S1, by advancing the screw 23, the molten resin in the cylinder 22 is discharged from the nozzle 24.

Subsequently, the control device 50 executes a metering step S2 in which a predetermined amount of molten resin is stored in the front side of the cylinder 22 by retracting the screw 23 to a predetermined position while rotating the screw 23. In S2 of the metering process, the molten resin is moved to the front end side of the cylinder 22 by rotating the screw 23 located at the front position, and the screw 23 is retreated to a predetermined position by the reaction of the forward movement of the molten resin. . In this way, a predetermined amount of molten resin is stored within the cylinder 22 between the tip of the screw 23 and the nozzle 24.

Subsequently, the control device 50 executes a nozzle touch step S3 in which the nozzle 24 is brought into contact with the mold 30 by moving the cylinder 22 forward. Note that, at this time, the mold 30 is assumed to be clamped. However, mold clamping may be performed after the nozzle touch step S3.

Subsequently, the control device 50 executes the following molding cycles S4 to S11. The control device 50 advances the screw 23 by controlling the speed of the screw 23 and executes an injection step S4 in which the molten resin is injected from the nozzle 24 into the mold 30. In the injection step S4, the molten resin flows from the nozzle 24 into the resin flow path P, and from the resin flow path P into the molded product cavity C. In the injection step S4, molten resin is supplied to most (for example, 90 to 95%) of the molded product cavity C.

Following the injection step S4, the control device 50 executes a pressure holding step S5 in which a holding pressure is applied to the molten resin in the molded product cavity C by controlling the pressure applied to the screw 23. In the pressure holding step S5, by controlling the screw 23 to apply a predetermined pressure, the screw 23 is further advanced, and molten resin is supplied from the nozzle 24 to the molded product cavity C via the resin flow path P. . In the pressure holding step S5, the molded product cavity C is completely filled with the molten resin.

Subsequently, the control device 50 stops applying pressure to the screw 23 and stops heating the mold 30 to cool the mold 30, thereby cooling the molten resin in the mold 30 (cooling step S6). Execute. In the cooling step S6, the molten resin in the mold 30 is solidified. Following the cooling step S6, the control device 50 controls the mold clamping device 40 to separate the second mold 32 from the first mold 31 and execute a mold release/molded product removal step S7 in which the molded product is taken out. . Subsequently, the control device 50 controls the mold clamping device 40 to perform a mold clamping step S8 in which the second mold 32 is aligned with the first mold 31 and the molds are clamped.

Furthermore, after completing the pressure holding step S5, the control device 50 executes a nozzle separating step S9 in which the nozzle 24 is separated from the mold 30 by retracting the cylinder 22. Following the nozzle separation step S9, the control device 50 moves the molten resin to the front end side of the cylinder 22 by rotating the screw 23 located at the front position, and causes the screw 23 to move due to the reaction of the forward movement of the molten resin. By retreating to a predetermined position, a measuring step S10 is executed in which a predetermined amount of molten resin is stored on the front side of the cylinder 22.

After the mold clamping step S8 and the measuring step S10 are completed, the control device 50 executes a nozzle touch step S11 in which the nozzle 24 is brought into contact with the mold 30 by advancing the cylinder 22. However, the mold clamping step S8 may be performed after the nozzle touch step S11. After the nozzle touch step S11, the injection step S4 described above is repeated again.

(4. Behavior of discharge pressure and mold internal pressure)
Regarding the behavior (time change) of the acquired pressure of the in-mold resin pressure acquisition device 33 (331 to 334) and the discharge pressure acquisition device 27 in the injection process S4 and the pressure holding process S5, FIGS. 5(a), (b) and FIG. This will be explained with reference to 6(a) and 6(b). First, the state in which each gate P3 is free from clogging will be described with reference to FIGS. 5(a) and 5(b). Note that the in-mold resin pressure acquisition device 331 acquires the in-mold resin pressure A, the in-mold resin pressure acquisition device 332 acquires the in-mold resin pressure B, and the in-mold resin pressure acquisition device 333 acquires the in-mold resin pressure B. It is assumed that the in-mold resin pressure C is acquired, and the in-mold resin pressure acquisition device 334 acquires the in-mold resin pressure D.

As shown in FIGS. 5A and 5B, at time t1, the injection process S4 is started, so that the screw 23 moves forward and the discharge pressure increases. Thereafter, in this embodiment, the forward speed of the screw 23 is initially set to a low speed and then switched to a high speed.

As shown in FIGS. 5(a) and 5(b), when the forward speed of the screw 23 is switched to high speed, the molten resin flows into the resin flow path P of the mold 30, which increases the discharge pressure and the resin pressure inside the mold. rises rapidly. Then, by flowing into the molded product cavity C from the gate P3 of the resin flow path P, the discharge pressure and the resin pressure in the mold decrease slightly, and then gradually increase. Therefore, in the injection step S4, the discharge pressure reaches its maximum value at the discharge pressure peak time t2. The time at which the injection step S4 ends is t4, and in the injection step S4, the time between the discharge pressure peak time t2 and the end time t4 of the injection step is t3. The time t3 is, for example, an intermediate time between the pressure peak time t2 and the injection process end time t4, but it may also be a time shifted from the intermediate time.

As shown in FIG. 5A, by switching from the injection process S4 to the pressure holding process S5, the discharge pressure and the resin pressure in the mold are reduced to near the desired holding pressure by pressure control in the pressure holding process S5. Usually, immediately after the discharge pressure and the resin pressure in the mold decrease to a pressure slightly lower than the desired holding pressure, they increase toward the vicinity of the desired holding pressure.

Then, when the pressure holding step S5 is continued and the molded product cavity C is completely filled with the molten resin, that is, at the time of completion of filling t5, the discharge pressure and the resin pressure in the mold increase. Since the discharge pressure is pressure controlled, it reaches the desired holding pressure immediately after that. On the other hand, the resin pressure within the mold gradually increases after the filling completion time t5.

Next, a case where the gate P32 is clogged will be described with reference to FIGS. 6(a) and 6(b). Compared to the case of FIG. 5(b) in which there is no gate clogging, in FIG. 6(b), the in-mold resin pressure obtained by the in-mold resin pressure obtaining device 332 disposed near the gate P32 in the injection process S4 is It can be seen that the rise of the pressure B is delayed and that the peak pressure in the injection step S4 is reduced. On the other hand, for the other in-mold resin pressures A, C, and D, the peak pressure in the injection step S4 is slightly increased.

(6. Injection molding apparatus 1 of first embodiment)
The injection molding apparatus 1 of the first embodiment will be described with reference to FIGS. 7 and 8. The injection molding apparatus 1 includes an injection device 20, a mold 30, a mold clamping device 40, a control device 50, and a computer device 60, as shown in FIG. In FIG. 7, only some functional parts of the injection molding apparatus 1 are illustrated. Further, the computer device 60 will be explained below.

The computer device 60 includes a determination section 61 and a storage section 62. The determination unit 61 is constituted by an arithmetic unit that constitutes the computer device 60 described above, and functions by executing a computer program. The storage unit 62 is constituted by a storage device that constitutes the computer device 60 described above.

The determination unit 61 determines whether each gate P3 (P31 to P34) is clogged based on the in-mold resin pressure acquired by the in-mold resin pressure acquisition device 33 and the discharge pressure acquired by the discharge pressure acquisition device 27. Determine the presence or absence. As described above, each gate P3 is located between the runner P2 and the molded product cavity C, and has a flow passage cross-sectional area smaller than that of the runner P2. Therefore, the gate P3 may become clogged with, for example, cold slag or foreign matter. The determination unit 61 determines whether or not each gate P3 is clogged. Furthermore, when the above-described molding cycle is continuously executed a plurality of times, a phenomenon may occur in which one of the gates P3 is temporarily clogged and then the gate clog is cleared. In this phenomenon, the determination unit 61 can determine whether or not the gate P3 is temporarily clogged.

Furthermore, the determination unit 61 determines whether or not each gate P3 is clogged based on the characteristic amounts of the resin pressures A to D in the mold and the characteristic amount of the discharge pressure, rather than the resin pressures A to D in the mold and the discharge pressure themselves. Determine. Therefore, the determination unit 61 extracts the feature amount from the obtained in-mold resin pressures A to D, and also extracts the feature amount from the obtained discharge pressure.

In this embodiment, the determination unit 61 determines whether or not the gate P3 is clogged using the characteristic amount of the resin pressure in the mold in the injection process S4 (time t1 to t4) and the characteristic value of the discharge pressure in the injection process S4. judge. In particular, the determination unit 61 uses the characteristic amount of the resin pressure in the mold and the characteristic amount of the discharge pressure after the discharge pressure reaches the pressure peak in the injection step S4, that is, from time t2 to t4.

More specifically, the determination unit 61 determines the in-mold resin pressures A to D in the rising portion of the pressure in the injection process S4, that is, in the later time period (t3 to t4) closer to the pressure holding process S5 in the injection process S4. and the characteristic amount of the discharge pressure in the later time period (t3 to t4) closer to the pressure holding step S5 in the injection step S4.

The feature amounts are, for example, the time integral value of the resin pressures A to D in the mold in the later time period (t3 to t4), the time integral value of the discharge pressure in the later time period (t3 to t4), and the like. Note that the feature quantities are the maximum value, minimum value, median value, average value, first quartile, third quartile, Variance, standard deviation, kurtosis, skewness, etc. may also be used. Further, the determination unit 61 may use a plurality of feature amounts.

Furthermore, in the present embodiment, the determination unit 61 applies machine learning to determine whether each of the gates P31 to P34 is clogged. Therefore, the determination unit 61 determines whether or not each of the gates P31 to P34 is clogged using a learned model generated in advance. In particular, when applying machine learning, the determination unit 61 can easily apply a plurality of feature amounts.

The storage unit 62 stores information used by the determination unit 61 to determine whether each of the gates P31 to P34 is clogged. In this embodiment, the storage unit 62 stores a trained model generated by performing machine learning using a training data set. The determination unit 61 uses the trained model stored in the storage unit 62.

The functions of the computer device 60 when applying machine learning will be described with reference to FIG. 8. As a learning phase, first, a training data set 63 is prepared. The training data set 63 includes a feature amount of resin pressure in the mold, a feature amount of discharge pressure, and label data indicating the presence or absence of clogging at each gate P31 to P34.

In the learning phase, the machine learning processing unit 64 in the computer device 60 performs machine learning using the training data set 63 to generate one learned model. The trained model is stored in the storage unit 62. In this embodiment, the trained model uses the feature amount of resin pressure in the mold and the feature amount of discharge pressure as explanatory variables, and uses the presence or absence of clogging of each gate P31 to P34 as an objective variable.

Subsequently, as an estimation phase, the determination unit 61 acquires the in-mold resin pressure and discharge pressure as detection data 65. Then, the determination unit 61 calculates the characteristic amount of the resin pressure in the mold, and also calculates the characteristic amount of the discharge pressure. Subsequently, the determination unit 61 uses the learned model stored in the storage unit 62 to input the characteristic amount of the resin pressure in the mold and the characteristic amount of the discharge pressure, thereby determining whether the gates P31 to P34 are clogged. Determine the presence or absence of (output).

In this embodiment, the learned model is used to determine the presence or absence of clogging at each gate P31 to P34, but instead of this, the storage unit 62 is stored in advance to determine the presence or absence of clogging at each gate P31 to P34. The determination unit 61 compares the characteristic amount of the resin pressure in the mold and the characteristic amount of the discharge pressure with the determination standard, and determines whether or not there is clogging at each gate P31 to P34. It may also be a thing. In the example shown in FIG. 9, in a two-dimensional map of the in-mold resin pressure at each gate P31 to P34 acquired by the in-mold resin pressure acquisition devices 331 to 334 and the discharge pressure acquired by the discharge pressure acquisition device 27, , it is determined that the gate is clogged below the criterion indicated by the straight line, and that the gate is not clogged above the criterion. Even in this case, it is possible to determine whether or not each of the gates P31 to P34 is clogged.

(7. Effects of Embodiment 1)
When molding a molded product, molten resin is supplied from the injection device 20 to the resin flow path P of the mold 30, and from the resin flow path P to the molded product cavity C. If the gate P3 of the resin flow path P of the mold 30 is clogged during molding, the molten resin will not flow from the resin flow path P to the molded product cavity C, or will be difficult to flow.

Then, focusing on the fact that the in-mold resin pressure in the resin flow path P fluctuates due to clogging of the gate P3, the determination unit 61 of the injection molding apparatus 1 determines whether the gate The presence or absence of clogging of each of the gates P31 to P34 is determined based on the characteristic amount of the resin pressure in the mold acquired by the resin pressure acquisition devices 331 to 334. By determining whether or not each of the gates P31 to P34 is clogged, it is possible to detect a decrease in the dimensional accuracy of the molded product, and it is possible to stabilize the dimensional accuracy.

In particular, by providing in-mold resin pressure acquisition devices 331 to 334 in the vicinity of each gate P31 to P34, as shown in FIG. 5(b) and FIG. 6(b), gates with clogging Changes in the mold resin pressure B acquired by the mold resin pressure acquisition device 332 provided at a position near P32 can be detected. Therefore, by using the feature quantity of the resin pressure in the mold, it is possible to determine with high precision whether or not each of the gates P31 to P34 is clogged.

Further, in determining whether or not the gate P3 is clogged, the determination unit 61 uses the characteristic amount of the discharge pressure in addition to the characteristic amount of the resin pressure in the mold. In the injection process S4, not only the resin pressure within the mold but also the discharge pressure changes depending on whether or not the gate P3 is clogged. Therefore, by using the feature amount of the discharge pressure in addition to the feature amount of the in-mold resin pressure, the determination unit 61 can determine whether or not each of the gates P31 to P3 is clogged with higher accuracy.

Further, the determination unit 61 uses data in the injection process S4 among the resin pressure in the mold and the discharge pressure. Particularly in the injection process S4, the pressure changes depending on whether or not the gate P3 is clogged. Therefore, by using the pressure data of the injection process S4, the determination unit 61 can highly accurately determine whether each of the gates P31 to P34 is clogged.

In this embodiment, the plurality of gates P31 to P34 are arranged in the circumferential direction, and the in-mold resin pressure acquisition devices 331 to 334 are arranged in the mold 30 to control gates P3 and P34 that are adjacent to each other among the plurality of gates P31 to P34. It is provided at a position closer to one of the gates P3 than the central position P4. As a result, the in-mold resin pressure acquisition devices 331 to 334 are reliably positioned near the gates P31 to P34, making it possible to determine with high precision whether or not each gate P31 to P34 is clogged. can.

In this embodiment, the in-mold resin pressure acquisition devices 331 to 334 are provided in the flat portion C1 of the molded product cavity C. This makes it possible to further improve the accuracy of pressure detection by the in-mold resin pressure acquisition devices 331 to 334, making it possible to determine with high precision whether or not each of the gates P31 to P34 is clogged.

In this embodiment, the control device 50 further includes a control device 50 that controls the injection device 20. A molding cycle including a holding pressure step S5 of applying holding pressure to the molten resin in C is executed. Then, the determination unit 61 determines whether or not there is resin clogging at each gate P31 to P34 based on the characteristic amounts of the resin pressures A to D in the mold in the injection process S4 and the characteristic amounts of the discharge pressure in the injection process S4. judge. Thereby, it is possible to determine with even higher precision whether or not each of the gates P31 to P34 is clogged.

In the present embodiment, the determination unit 61 determines whether the resin in the resin flow path is based on the characteristic amount of the resin pressure in the mold and the characteristic amount of the discharge pressure in the time period when the resin pressure in the mold rises in the injection process S4. Determine whether or not there is a blockage. As a result, changes in the resin pressure in the mold due to gate clogging are noticeable during the rising time of the resin pressure in the mold in the injection process S4, so that it is possible to check whether or not each gate P31 to P34 is clogged with higher accuracy. can be determined.

In the present embodiment, the determination unit 61 uses a learned model generated based on learning data including the correspondence between the feature amount of the resin pressure in the mold, the feature amount of the discharge pressure, and the presence or absence of resin clogging at the gate P3. The presence or absence of resin clogging in each of the gates P31 to P34 is determined based on the following or based on the determination criteria calculated from the learning data. When based on the above-mentioned trained model, it is possible to determine with high accuracy whether or not each of the gates P31 to P34 is clogged, even for products that are greatly affected by variations in materials and environment. When the above criteria are used, there is no need to prepare a learning model, so costs can be reduced.

[Embodiment 2]
In the injection molding apparatus 1 according to the second embodiment, as shown in FIG. 10, the plurality of runners P21 to P24 are respectively connected to the plurality of gates P31 to P32 arranged in the circumferential direction. In the mold 30, the in-mold resin pressure acquisition devices 331 to 334 move the gates from the central positions P41 to P44 between the gates P31 to P34 to which the plurality of runners P21 to P24 are connected, respectively, and the spool P1. It is located close to. Since the other configurations are the same as those in the first embodiment, the same reference numerals as in the first embodiment will be given and the description thereof will be omitted.

In the second embodiment as well, the in-mold resin pressure acquisition devices 331 to 334 are provided in the vicinity of the gates P31 to P34, so that it is possible to determine with high precision whether or not each of the gates P31 to P34 is clogged. However, since each of the runners P21 to P24 has a substantially conical shape or a shape that is a combination of a substantially conical shape and a substantially cylindrical shape, the runners P21 to P24 have a shape that is a combination of a substantially conical shape and a substantially cylindrical shape. , the detection accuracy of the resin pressure in the mold by the resin pressure acquisition devices 331 to 334 may be slightly inferior.

[Embodiment 3]
In the injection molding apparatus 1 according to the third embodiment, as shown in FIG. 11, the computer device 60 for determining gate clogging further includes a viscosity normalization section 66. The viscosity normalization unit 66 calculates a normalization coefficient that correlates to the current viscosity of the molten resin from the discharge pressure acquired by the discharge pressure acquisition device 27, and uses the normalization coefficient to adjust the discharge pressure and the resin pressure in the mold. Normalize. The viscosity normalization unit 66 does not acquire the viscosity of the molten resin, but estimates the degree of change in the viscosity of the molten resin from the change in the discharge pressure acquired by the discharge pressure acquisition device 27, and correlates it with the current viscosity. Calculate the normalization coefficient.

In the third embodiment, the determination unit 61 uses the discharge pressure and in-mold resin pressure normalized by the viscosity normalization unit 66 as the determination data shown in FIG. 8 to calculate respective feature quantities, Based on the feature amount, it is determined whether or not each gate P31 to P34 is clogged with resin. The other configurations are the same as those in the first embodiment, and are given the same reference numerals as in the first embodiment, and the description thereof will be omitted.

According to the third embodiment, it is possible to calculate the characteristic quantities of the discharge pressure and the resin pressure in the mold by taking into account changes in the viscosity of the molten material due to material lot variations and moisture content variations, resulting in higher accuracy. It is possible to determine whether or not each of the gates P31 to P34 is clogged.

The present invention is not limited to the embodiments and modifications described above, and can be applied to various embodiments without departing from the spirit thereof.

1: Injection molding device, 20: Injection device, 27: Discharge pressure acquisition device, 30: Mold, 33 (331 to 334): Resin pressure acquisition device in mold, 50: Control device, 60: Computer device, 61: Judgment unit, 62: Storage unit, 66: Viscosity normalization unit

Claims (8)

an injection device equipped with a nozzle that discharges molten resin;
A mold including a molded product cavity and a resin flow path that allows molten resin discharged from the nozzle to flow into the molded product cavity;
an in-mold resin pressure acquisition device that detects in-mold resin pressure that is the pressure of the resin material in the molded product cavity or in the resin flow path;
a discharge pressure acquisition device that acquires the discharge pressure of the molten resin discharged from the nozzle;
A feature quantity is calculated based on the above-mentioned in-mold resin pressure acquired by the above-mentioned in-mold resin pressure acquisition device and the above-mentioned discharge pressure acquired by the above-mentioned discharge pressure acquisition device. a determination unit that determines whether or not there is resin clogging in the resin flow path;
Equipped with
The resin flow path includes a plurality of gates connected to the molded product cavity, a plurality of runners respectively connected to the plurality of gates, and a spool connected to the plurality of runners and the nozzle,
The in-mold resin pressure acquisition device is an injection molding apparatus provided in a position near each of the plurality of gates in the mold. The above multiple gates are arranged in the circumferential direction,
The in-mold resin pressure acquisition device is provided in the mold at a position closer to one of the plurality of gates than to a central position of the gates that are adjacent to each other. Injection molding equipment. The injection molding apparatus according to claim 2, wherein the in-mold resin pressure acquisition device is provided on a flat surface of the molded product cavity. The plurality of runners are each connected to the plurality of gates arranged in the circumferential direction,
1 . The in-mold resin pressure acquisition device is provided in the mold at a position closer to the gate than a central position between the gate and the spool to which the plurality of runners are respectively connected. The injection molding apparatus described in . further comprising a control device that controls the injection device,
The above control device is
an injection step of injecting molten resin from the nozzle to the mold;
Following the injection step, a holding pressure step of applying holding pressure to the molten resin in the molded product cavity;
Run a molding cycle including
The determination unit determines whether resin is clogged at each gate based on a characteristic amount of the resin pressure in the mold in the injection step and a characteristic amount of the discharge pressure in the injection step. The injection molding apparatus according to any one of 1 to 4. The determination unit determines whether the resin flow path is clogged with resin based on the characteristic amount of the resin pressure in the mold and the characteristic amount of the discharge pressure in the time period during which the resin pressure in the mold rises during the injection process. The injection molding apparatus according to claim 5, which determines the presence or absence of. The determination unit uses a learned model generated based on learning data including a correspondence relationship between the feature amount of the resin pressure in the mold, the feature amount of the discharge pressure, and the presence or absence of resin clogging in the resin flow path. The injection molding apparatus according to any one of claims 1 to 4, wherein the injection molding apparatus determines whether or not there is resin clogging in the resin flow path based on the determination criteria calculated from the learning data. A normalization coefficient correlated to the current viscosity of the molten resin is calculated from the discharge pressure acquired by the discharge pressure acquisition device, and the discharge pressure and the resin pressure in the mold are normalized using the normalization coefficient. further comprising a viscosity normalization section,
The determination unit calculates characteristic quantities of the discharge pressure and the resin pressure in the mold that have been normalized by the viscosity normalization unit, and determines whether or not there is resin clogging in the resin flow path based on the characteristic quantities. The injection molding apparatus according to any one of claims 1 to 4, wherein the injection molding apparatus is determined.

Images