Determination device and determination method

Abstract

A determination device (70) is provided with: a load acquisition unit (82) that acquires a load (LO) applied to a screw (34) of an injection molding machine (10) as a resin is injected in a plurality of molding cycles; an operation information acquisition unit (86) that acquires operation information (INF) on the screw (34) before the load (LO) exceeds a first threshold (TH1); a statistical amount calculation unit (88) that calculates a statistical amount (ST) on the basis of a plurality of pieces of the operation information (INF); and a determination unit (92) that determines the quality of a state of the resin measured by the injection molding machine (10) on the basis of the statistical amount (ST).

Description

Technical Field

[0006]

[0001] The present invention relates to a determination device and a determination method for determining whether the state of resin measured by an injection molding machine is good or not.

Background Art

[0002] An injection molding machine is an industrial machine that mass-produces molded products by repeatedly executing a molding cycle including a plurality of steps. The molding cycle includes a metering step and an injection step (see also Japanese Patent Laid-Open No. 10-16016). The metering step is a step for metering the resin to be injected into the mold. The injection step is a step for injecting the metered resin into the mold. The resin injected into the mold is solidified to complete the molded product.

Summary of the Invention

[0003] During a plurality of molding cycles, the state of the metered resin may vary. That is, during a plurality of molding cycles, the temperature, viscosity, density, resin amount, etc. of the metered resin may vary.

[0004] Variations in the state of the metered resin cause variations in the quality (mass, shape, etc.) of the molded product. However, it is difficult for an operator to determine whether the state of the resin measured in a certain molding cycle varies compared to the state of the resin measured in other molding cycles. That is, it is difficult for an operator to determine whether the state of the metered resin is good or not.

[0005] 。 An object of the present invention is to solve the above-described problems.

[0006] A first aspect of the present invention is a determination device for determining the quality of the condition of a resin measured in an injection molding machine, which includes a cylinder and a screw for injecting the resin measured in the cylinder into a mold, the determination device comprising: a load acquisition unit that acquires the load applied to the screw in accordance with the injection of the resin from the cylinder into the mold in a plurality of molding cycles; an operation information acquisition unit that acquires operation information including at least one of the amount of movement, rotation, and time required of the screw from the time the screw starts the injection operation to inject the resin into the mold until the load exceeds a first threshold in a plurality of molding cycles; a statistical quantity calculation unit that calculates at least one of the amount of movement, rotation, and time required based on a plurality of operation information acquired in a plurality of molding cycles; and a determination unit that determines the quality of the condition of the measured resin based on the statistical quantity.

[0007] A second aspect of the present invention is a determination method for determining the quality of a resin measured in an injection molding machine comprising a cylinder and a screw for injecting a resin measured in the cylinder into a mold, the determination method comprising: a load acquisition step of acquiring the load applied to the screw in accordance with the injection of the resin from the cylinder into the mold in a plurality of molding cycles; an operation information acquisition step of acquiring operation information including at least one of the amount of movement of the screw, the amount of rotation, and the required time from the time the screw starts the injection operation for injecting the resin into the mold until the load exceeds a threshold in a plurality of molding cycles; a statistical quantity calculation step of calculating at least one of the amount of movement, the amount of rotation, and the required time based on a plurality of operation information acquired in a plurality of molding cycles; and a determination step of determining the quality of the measured resin based on the statistical quantity.

[0008] According to the present invention, it is possible to determine whether the measured resin is in good condition or not. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a diagram showing the configuration of an injection molding system according to an embodiment. [Figure 2] Figure 2 is a schematic diagram of the injection device. [Figure 3] Figure 3 is a configuration diagram of the determination device according to the embodiment. [Figure 4] Figure 4 is an example of a threshold table. [Figure 5] Figure 5 is a time chart illustrating the time progression of the screw load (resin pressure) during the injection process of each molding cycle, for a molding cycle that is repeated three times. [Figure 6] Figure 6 is a flowchart illustrating the flow of the determination method according to the embodiment. [Figure 7] Figure 7 is a diagram showing the configuration of the determination device according to modified example 6. [Figure 8] Figure 8 is a diagram showing the configuration of the determination device according to Modification 7. [Figure 9] Figure 9 is a flowchart illustrating the flow of the determination method according to Modification Example 7. [Figure 10] Figure 10 is a diagram showing the configuration of an injection molding system according to modified example 13. [Figure 11] Figure 11 is a diagram showing the configuration of another injection molding system related to the modified example 13. [Modes for carrying out the invention]

[0010] [Embodiment] Figure 1 is a diagram showing the configuration of the injection molding system SYS according to an embodiment.

[0011] The injection molding system SYS comprises an injection molding machine 10 and a determination device 70.

[0012] The injection molding machine 10 comprises a mold clamping device 12, an injection device 14, a machine base 16, and a control device 18. Arrow D1 in Figure 1 indicates the forward direction in this embodiment. Arrow D2 in Figure 1 indicates the rearward direction in this embodiment. The rearward direction is the opposite direction to the forward direction.

[0013] The mold clamping device 12 is a device for opening and closing the mold 20. The mold clamping device 12 is arranged in front of the injection device 14. Note that the mold 20 opens and closes in the front-rear direction. The closed mold 20 forms a cavity 20c. The mold 20 in FIG. 1 is in the closed state. The mold clamping device 12 can apply a mold clamping force to the mold 20 so that the closed state of the mold 20 is maintained. However, a more detailed description of the mold clamping device 12 is omitted.

[0014] The machine base 16 supports the mold clamping device 12 and the injection device 14. However, the machine base 16 may support only the injection device 14 among the mold clamping device 12 and the injection device 14. A guide rail 22 is installed on the machine base 16. The guide rail 22 extends in the front-rear direction.

[0015] The injection device 14 is supported by a slide base 24. The slide base 24 is guided by the guide rail 22 and slides in the front-rear direction. Therefore, the injection device 14 slides in the front-rear direction together with the slide base 24.

[0016] The injection device 14 includes a cylinder 26. The cylinder 26 is a cylindrical member that extends toward the front of the injection device 14.

[0017] FIG. 2 is a schematic configuration diagram of the injection device 14.

[0018] The axis LA of the cylinder 26 extends parallel to the front-rear direction. The cylinder 26 includes a hopper 28, a heater 30, a temperature sensor 31, a nozzle 32, and a screw 34. Further, the injection device 14 further includes a first drive device 36, a second drive device 38, and a pressure sensor 40.

[0019] The hopper 28 is arranged at the rear end portion 26r of the cylinder 26. The hopper 28 stores solid resin (pellets). The resin is a raw material for the molded product produced by the injection molding machine 10. Further, the hopper 28 has a supply port 28o. The resin in the hopper 28 is supplied into the cylinder 26 through the supply port 28o.

[0020] The heater 30 heats the cylinder 26. When the cylinder 26 is heated, the resin inside the cylinder 26 is heated. The heater 30 is composed of, for example, a plurality of band heaters. The plurality of band heaters are wound around the cylinder 26.

[0021] The temperature sensor 31 is a sensor that outputs a detection signal according to the temperature of the cylinder 26. The detection signal of the temperature sensor 31 is input to the control device 18. The temperature sensor 31 is, for example, a thermocouple. The temperature sensor 31 is arranged on the surface of the cylinder 26 or in a hole formed on the surface of the cylinder 26. The cylinder 26 may be provided with a plurality of temperature sensors 31 (see also FIG. 2). A detailed description of the control device 18 will be given later.

[0022] The nozzle 32 is attached to the front end portion 26f of the cylinder 26. Also, the nozzle 32 is connected to the mold 20. The nozzle 32 has an injection port 32p for injecting resin. When the nozzle 32 and the mold 20 are connected, the resin inside the cylinder 26 is injected from the injection port 32p into the cavity 20c.

[0023] The screw 34 is arranged inside the cylinder 26. The axis LA of the cylinder 26 is also the axis of the screw 34. The screw 34 has a flight portion 42, a screw head 44, a check sheet 46, and a backflow prevention ring 48.

[0024] The flight portion 42 has a single spiral shape and is formed on the surface of the screw 34. However, the flight portion 42 may have a double spiral shape. The flight portion 42 and the inner wall 26i of the cylinder 26 form a flow path 50 inside the cylinder 26. The flow path 50 is formed so as to guide the resin supplied into the cylinder 26 from the rear end portion 26r to the front end portion 26f.

[0025] The screw head 44 is the front end portion of the screw 34. The check sheet 46 is arranged behind the screw head �. The backflow prevention ring 48 is arranged between the screw head 44 and the check sheet 46.

[0026] When forward pressure is applied to the backflow prevention ring 48, it moves forward in response to the pressure within the range between the screw head 44 and the check sheet 46. As the backflow prevention ring 48 moves forward, it moves away from the check sheet 46. This causes the backflow prevention ring 48 to open the flow path 50. The flow path 50 is opened to its widest extent when the backflow prevention ring 48 is in contact with the rear end of the screw head 44.

[0027] Furthermore, when a backward pressure is applied to the backflow prevention ring 48, it moves backward in response to the pressure within the range between the screw head 44 and the check sheet 46. By moving backward, the backflow prevention ring 48 approaches the check sheet 46. This causes the backflow prevention ring 48 to close the flow path 50. When the backflow prevention ring 48 is in contact with the front end of the check sheet 46, the flow path 50 becomes narrowest.

[0028] The first drive unit 36 ​​is a device for rotating the screw 34. The first drive unit 36 ​​comprises a first motor 52a, a first drive pulley 54a, a first belt member 56a, and a first driven pulley 58a.

[0029] The first motor 52a is, for example, a servo motor. The first motor 52a comprises a first shaft 60a, a first position and speed sensor 62a, and a first current and torque sensor 63a. The first shaft 60a rotates in accordance with the drive current supplied to the first motor 52a. The first position and speed sensor 62a outputs a detection signal to the control device 18 corresponding to the rotational position of the first shaft 60a. The first current and torque sensor 63a outputs a detection signal to the control device 18 corresponding to the drive current supplied to the first motor 52a, the rotational torque of the first shaft 60a, etc.

[0030] The first drive pulley 54a is connected to the first shaft 60a. The first drive pulley 54a rotates in accordance with the rotation of the first shaft 60a. The first belt member 56a is stretched between the first drive pulley 54a and the first driven pulley 58a. As a result, the rotation of the first drive pulley 54a is transmitted to the first driven pulley 58a via the first belt member 56a. Consequently, the first driven pulley 58a also rotates in accordance with the rotation of the first drive pulley 54a.

[0031] The first driven pulley 58a is integrally mounted with the screw 34. Therefore, the screw 34 rotates in accordance with the rotation of the first driven pulley 58a. The screw 34 rotates around the axis LA. By rotating, the screw 34 can cause the resin inside the cylinder 26 to flow along the flow path 50. The rotation direction of the first shaft 60a is switched according to the control of the control device 18. In accordance with the switching of the rotation direction of the first shaft 60a, the rotation direction of the screw 34 is also switched. The switching of the rotation direction of the screw 34 changes the flow direction of the resin inside the cylinder 26.

[0032] In the following description, the rotation direction of screw 34 when the resin flows forward will also be referred to as the forward rotation direction. Furthermore, the rotational motion of screw 34 in the forward rotation direction will also be referred to as forward rotation.

[0033] On the other hand, in the following explanation, the rotation direction of screw 34 when the resin flows backward is also referred to as the reverse rotation direction. Furthermore, the rotational movement of screw 34 in the reverse rotation direction is also referred to as reverse rotation.

[0034] The second drive unit 38 is a device that moves the screw 34 back and forth inside the cylinder 26. The second drive unit 38 comprises a second motor 52b, a second drive pulley 54b, a second belt member 56b, a second driven pulley 58b, a ball screw 64, and a nut 66.

[0035] The second motor 52b is, for example, a servo motor. The second motor 52b comprises a second shaft 60b, a second position and speed sensor 62b, and a second current and torque sensor 63b. The second shaft 60b rotates in accordance with the drive current supplied to the second motor 52b. The second position and speed sensor 62b outputs a detection signal to the control device 18 corresponding to the rotational position of the second shaft 60b. The second current and torque sensor 63b outputs a detection signal to the control device 18 corresponding to the drive current supplied to the second motor 52b, the rotational torque of the second shaft 60b, etc.

[0036] The second drive pulley 54b is connected to the second shaft 60b. The second drive pulley 54b rotates in accordance with the rotation of the second shaft 60b. The second belt member 56b is stretched between the second drive pulley 54b and the second driven pulley 58b. As a result, the rotation of the second drive pulley 54b is transmitted to the second driven pulley 58b via the second belt member 56b. Consequently, the second driven pulley 58b also rotates in accordance with the rotation of the second drive pulley 54b.

[0037] The second driven pulley 58b is connected to the ball screw 64. The second driven pulley 58b rotates in accordance with the rotation of the second drive pulley 54b, which is transmitted via the second belt member 56b. Therefore, the ball screw 64 also rotates in accordance with the rotation of the second driven pulley 58b.

[0038] The nut 66 is screwed onto the ball screw 64. As the ball screw 64 rotates, the relative positional relationship between the nut 66 and the ball screw 64 changes in the direction of the ball screw 64's axis. The axis of the ball screw 64 is parallel to the axis LA of the cylinder 26 (screw 34). Therefore, the relative positional relationship between the nut 66 and the ball screw 64 changes parallel to the axis LA of the screw 34 in accordance with the rotation of the ball screw 64. In other words, the relative positional relationship between the nut 66 and the ball screw 64 changes in the front-rear direction in accordance with the rotation of the ball screw 64.

[0039] The screw 34 and the ball screw 64 are connected in such a way that the rotational force of the ball screw 64 (second shaft 60b) is not transmitted to the screw 34. The method of this connection is known in the art. Therefore, a detailed explanation of the connection method is omitted.

[0040] Since the screw 34 is connected to the ball screw 64, it moves back and forth inside the cylinder 26 in response to changes in the relative positional relationship between the nut 66 and the ball screw 64 in the front-rear direction. In other words, the screw 34 moves back and forth in response to the rotation of the ball screw 64. However, since the rotational force of the ball screw 64 is not transmitted to the screw 34, the screw 34 does not rotate in response to the rotation of the ball screw 64.

[0041] The rotation direction of the second shaft 60b is switched according to the control of the control device 18. The rotation direction of the ball screw 64 is also switched in accordance with the switching of the rotation direction of the second shaft 60b. The switching of the rotation direction of the ball screw 64 switches the direction of movement between the nut 66 and the screw 34.

[0042] According to the injection device 14 described above, the resin supplied from the hopper 28 into the cylinder 26 flows forward along the flow path 50 as the screw 34 rotates in the forward direction. As the resin flows along the flow path 50, it melts under the influence of the heat from the heater 30 transmitted through the cylinder 26 and the shear heat generated in the resin by shearing by the flight section 42.

[0043] As the screw 34 continues to rotate forward, the resin behind the backflow prevention ring 48 flows forward along the flow path 50 and reaches the backflow prevention ring 48. The resin that reaches the backflow prevention ring 48 pushes it forward. This causes the backflow prevention ring 48 to move forward within the range between the screw head 44 and the check sheet 46, opening the flow path 50. The resin then passes through the opened flow path 50 and reaches the area inside the cylinder 26 that is forward of the screw head 44.

[0044] In the following description, the area inside the cylinder 26 in front of the screw head 44 will also be referred to as the metering area. Furthermore, in the following description, unless otherwise specified, the amount of resin refers to the amount of resin accumulated in the metering area.

[0045] The resin accumulated in the metering area presses the screw head 44 backward. In the following description, unless otherwise specified, the resin pressure refers to the backward pressure exerted on the screw 34 by the resin in the metering area.

[0046] The pressure sensor 40 is a sensor for detecting the pressure of the resin. The pressure sensor 40 is, for example, a load cell. The pressure sensor 40 outputs a detection signal corresponding to the pressure of the resin to the control device 18.

[0047] The control device 18 is, for example, a numerical control device. The control device 18 comprises one or more processors and one or more memories. A predetermined control program 68 is stored in the memory of the control device 18. The processor of the control device 18 controls the clamping device 12 and the injection device 14 by executing the control program 68. For example, the control device 18 executes the metering process, the depressurization process, and the injection process described below by executing the control program 68.

[0048] Furthermore, the initial position of the screw 34 (screw head 44) ​​at the start of the weighing process is the furthest forward position within the range of movement in the front-to-back direction inside the cylinder 26.

[0049] (Weighing process) The control device 18 controls the first motor 52a to rotate the screw 34 in the forward direction. As a result, the resin supplied from the hopper 28 into the cylinder 26 is pumped forward along the flow path 50. The resin flowing forward inside the cylinder 26 melts as it reaches the metering area. The amount of resin gradually increases as the control device 18 continues to rotate the screw 34 in the forward direction.

[0050] Here, the control device 18 controls the first motor 52a so that the screw 34 rotates forward at a predetermined rotational speed. For example, the memory of the control device 18 stores a predetermined metering condition value CV in advance. The metering condition value CV includes the target rotational speed of the screw 34 during the metering process. This target rotational speed may be any rotational speed instructed by the operator, or it may be a rotational speed specified by the manufacturer of the injection molding machine 10. Based on this target rotational speed, the control device 18 rotates the screw 34 forward.

[0051] The rotational speed of the screw 34 is the amount of rotation of the screw 34 per unit time. The control device 18 rotates the screw 34 forward while appropriately calculating the amount of rotation, rotational speed, etc. of the screw 34 based on the detection signal of the second position speed sensor 62b.

[0052] As the amount of resin increases, the screw 34 retracts. Here, the control device 18 controls the second motor 52b to prevent the screw 34 from retracting excessively. That is, the control device 18 controls the second motor 52b to adjust the retraction speed (rearward movement speed) of the screw 34. This prevents the resin pressure from dropping excessively as the screw 34 retracts.

[0053] Here, the control device 18 controls the second motor 52b so that the resin pressure is adjusted to a predetermined pressure while the screw 34 rotates forward. For example, the metering condition value CV includes a target pressure during the metering process. This target pressure, like the target rotational speed, may be any pressure instructed by the operator or a pressure specified by the manufacturer of the injection molding machine 10. Based on this target pressure, the control device 18 adjusts the retraction speed of the screw 34 during the metering process.

[0054] The retraction speed of the screw 34 is the amount of retraction of the screw 34 per unit time. The control device 18 retracts the screw 34 while appropriately calculating the amount of retraction (amount of movement), retraction speed, etc. of the screw 34 based on the detection signal of the first position speed sensor 62a.

[0055] As the amount of resin increases, the screw 34 retracts and reaches a predetermined position (metering position). The metering position is located behind the initial position of the screw 34 in the metering process. The control device 18 adjusts the resin pressure to the metering pressure and moves the screw 34 to the metering position, thereby accumulating a predetermined amount of resin in the metering area. When the screw 34 reaches the metering position, the control device 18 controls the first motor 52a to stop the forward rotation of the screw 34. This completes the metering process.

[0056] The metering condition value CV may include the target temperature of the cylinder 26. In that case, the control device 18 may control the heater 30 based on the target temperature. This adjusts the temperature of the cylinder 26 during the metering process based on the target temperature. By adjusting the temperature of the cylinder 26, the temperature of the resin inside the cylinder 26 is adjusted. Here, the control device 18 controls the heater 30 while appropriately calculating the temperature of the cylinder 26 based on, for example, the detection signal of the temperature sensor 31.

[0057] Furthermore, as mentioned above, shear heat is generated as the flight section 42 shears the resin. This shear heat affects the temperature of the cylinder 26. Here, the higher the rotational speed of the screw 34, the greater the shear heat. On the other hand, the lower the rotational speed of the screw 34, the less the increase in shear heat is suppressed. Based on this, the control device 18 may adjust the temperature of the cylinder 26 by adjusting the rotational speed of the screw 34.

[0058] (Depressurization process) The control device 18 starts a depressurization process after a predetermined amount of resin has been metered in the cylinder 26. During the depressurization process, the control device 18 controls the first motor 52a to rotate the screw 34 in reverse. When the screw 34 rotates in reverse, the resin in the metering area flows backward. This reduces the amount of resin. As the amount of resin decreases, the pressure of the resin applied to the screw 34 is reduced.

[0059] Furthermore, inertia acts on the screw 34, which rotates in the forward direction during the metering process. Therefore, the screw 34 continues to rotate in the forward direction even after reaching the metering position during the metering process. As a result, the amount of resin immediately after metering strictly exceeds the predetermined amount. The control device 18 can also adjust the amount of resin to be closer to the predetermined amount by reducing the amount of resin in accordance with the reverse rotation of the screw 34 during the depressurization process.

[0060] Furthermore, the backflow prevention ring 48 is pressed by the resin flowing from the metering area to the rear of the backflow prevention ring 48 in response to the control device 18 reversing the rotation of the screw 34. As a result, the backflow prevention ring 48 moves backward. As the backflow prevention ring 48 moves backward, it comes into contact with the check sheet 46 located behind it. When the backflow prevention ring 48 comes into contact with the check sheet 46, the flow path 50 is closed. With the flow path 50 closed, the resin accumulated in the metering area cannot reach the rear of the backflow prevention ring 48. As a result, the amount of resin is prevented from decreasing more than necessary.

[0061] The control device 18 controls the screw 34 based on the target pressure reduction value. The target pressure reduction value indicates the target pressure of the resin to be reduced in the depressurization process. The target pressure reduction value is, for example, atmospheric pressure. However, the operator or the manufacturer of the injection molding machine 10 may set the target pressure reduction value in the control device 18. The control device 18 terminates the depressurization process when the resin pressure reaches the target pressure reduction value.

[0062] (injection process) The control device 18 starts the injection process after the depressurization process is completed. The injection process is performed with the mold 20 in a closed state. Therefore, the control device 18 controls the clamping device 12 to close the mold 20 before the injection process starts.

[0063] In the injection process, the control device 18 controls the second motor 52b to advance the screw 34. As a result, the resin in the metering area is injected through the nozzle 32 towards the cavity 20c of the mold 20. The injected resin solidifies in the cavity 20c, completing the molded product.

[0064] The molding cycle of the injection molding machine 10 includes the metering process, depressurization process, and injection process described above. The injection molding machine 10 can mass-produce molded products by repeatedly executing the molding cycle.

[0065] Figure 3 is a configuration diagram of the determination device 70 according to the embodiment.

[0066] The judgment device 70 is an electronic device (computer) that determines whether the resin measured by the injection molding machine 10 is of good or bad condition.

[0067] The determination device 70 is connected to the control device 18 in a communicative manner. For example, the determination device 70 communicates with the control device 18 via a predetermined network. This allows the determination device 70 and the control device 18 to acquire each other's data. The predetermined network may be a wireless network or a wired network. The predetermined network can be implemented using, for example, serial communication, optical communication, or a wireless LAN.

[0068] The determination device 70 comprises a display unit 72, an operation unit 74, a storage unit 76, and a calculation unit 78.

[0069] The display unit 72 is a display device equipped with a display screen 72d. The material of the display screen 72d includes, for example, liquid crystal or OEL (organic electro-luminescence).

[0070] The operation unit 74 is an input device that receives information input to the determination device 70. The operation unit 74 includes, for example, an operation panel 74a, a touch panel 74b, etc. However, the operation unit 74 may also include a keyboard, mouse, etc. The touch panel 74b is installed on the display screen 72d.

[0071] The memory unit 76 includes a memory circuit. This memory circuit includes one or more memories, such as RAM (Random Access Memory) or ROM (Read Only Memory).

[0072] The memory unit 76 stores the determination program 80. The determination program 80 is a program that causes the determination device 70 to execute the determination method according to this embodiment.

[0073] The data stored in the storage unit 76 is not limited to the determination program 80. As mentioned above, the storage unit 76 may store various types of data as needed. For example, the storage unit 76 may store the pressure of the resin obtained based on the detection signal of the pressure sensor 40. The storage unit 76 may also store, for example, the torque of the first motor 52a (first torque) obtained based on the detection signal of the first current torque sensor 63a, the torque of the second motor 52b (second torque) obtained based on the detection signal of the second current torque sensor 63b, etc. Furthermore, the storage unit 76 may store, for example, the drive current of the first motor 52a or the second motor 52b, the voltage, the temperature of the cylinder 26, etc. All of the above pressure, first torque, second torque, drive current, voltage, temperature, etc. may be obtained from the control device 18.

[0074] The arithmetic unit 78 includes a processing circuit. This processing circuit includes, for example, one or more processors. However, the processing circuit of the arithmetic unit 78 may include integrated circuits such as ASICs (Application Specific Integrated Circuits) and FPGAs (Field-Programmable Gate Arrays). The processing circuit of the arithmetic unit 78 may also include discrete devices.

[0075] The arithmetic unit 78 includes a load acquisition unit 82, a threshold determination unit 84, an operation information acquisition unit 86, a statistical calculation unit 88, a range determination unit 90, a determination unit 92, a correction command unit 94, and a display control unit 96. The load acquisition unit 82, threshold determination unit 84, operation information acquisition unit 86, statistical calculation unit 88, range determination unit 90, determination unit 92, correction command unit 94, and display control unit 96 are realized by the processor of the arithmetic unit 78 executing a determination program 80. However, at least a part of the load acquisition unit 82, threshold determination unit 84, operation information acquisition unit 86, statistical calculation unit 88, range determination unit 90, determination unit 92, correction command unit 94, and display control unit 96 may be realized by the aforementioned integrated circuits, discrete devices, etc.

[0076] The load acquisition unit 82 acquires the load LO applied to the screw 34 as resin is injected from the cylinder 26 into the mold 20. Load LO is, for example, the pressure of the resin. Therefore, the load acquisition unit 82 acquires the pressure of the resin from the control device 18, for example, via a predetermined network.

[0077] The load acquisition unit 82 acquires the load LO in each of the multiple molding cycles. The storage unit 76 may store the multiple load LOs acquired in the multiple molding cycles.

[0078] The threshold determination unit 84 determines the first threshold TH1 based on the threshold table TB. The first threshold TH1 is a value used by the operation information acquisition unit 86 for processing. The processing details of the operation information acquisition unit 86 will be described later. The threshold table TB is a data table in which multiple first thresholds TH1 are stored according to at least one of the multiple types of screws 34 and the multiple types of resin. The threshold table TB is pre-stored in the storage unit 76.

[0079] The threshold determination unit 84 searches the threshold table TB for a first threshold TH1 corresponding to the type of screw 34 provided in the injection molding machine 10 and the type of resin supplied into the cylinder 26. The type of screw 34 provided in the injection molding machine 10 and the type of resin supplied into the cylinder 26 are, for example, instructed to the threshold determination unit 84 by the operator via the operation unit 74.

[0080] Figure 4 is an example of a threshold table TB.

[0081] The first column (type of screw 34) of the threshold table TB illustrated in Figure 4 stores multiple types of screws 34. For illustrative purposes, Figure 4 shows full-flight screws, barrier-flight screws, and highly plasticized screws as examples of multiple types of screws 34. For example, as mentioned above, the screw 34 rotates forward during the metering process, pressurizing the resin supplied to the inside of the cylinder 26 forward along the flow path 50. Here, the performance of pressurizing the resin supplied to the inside of the cylinder 26 forward along the flow path 50 differs depending on the type of screw 34. Therefore, the metering condition value CV required to obtain a good molded product differs depending on the type of screw 34.

[0082] The second column (type of resin) of the threshold table TB illustrated in Figure 4 stores multiple types of resin. For illustrative purposes, Figure 4 shows PA (polyamide), PBT (polybutylene terephthalate), and PE (polyethylene) as examples of multiple types of resin. For example, the melting temperature of the resin, the viscosity of the molten resin in the metering process, and the density of the molten resin in the metering process differ depending on the type of resin.

[0083] In the third column (first threshold) of the threshold table TB illustrated in Figure 4, multiple first thresholds TH1 (th1~th7) corresponding to the data in the first and second columns are stored. The specific values ​​of each of the multiple first thresholds TH1 are predetermined based on experiments. As shown in the bottom row of Figure 4, regardless of the type of resin, first thresholds TH1 corresponding to the type of screw 34 may be stored in the threshold table TB. Also, regardless of the type of screw 34, first thresholds TH1 corresponding to the type of resin may be stored in the threshold table TB. Furthermore, the injection molding machine 10 may produce molded products using a mixed resin, which is a mixture of multiple types of resins, as the raw material. In that case, multiple first thresholds TH1 corresponding to the proportion of each resin contained in the mixed resin may be stored in the threshold table TB.

[0084] The operation information acquisition unit 86 acquires operation information INF related to the screw 34. The operation information INF includes, for example, the time required from when the screw 34 starts the injection operation (forward operation) to inject resin into the mold 20 until the load LO exceeds the first threshold TH1.

[0085] The operation information acquisition unit 86 acquires operation information INF in multiple molding cycles. The storage unit 76 may store multiple operation information INF acquired by the operation information acquisition unit 86 in multiple molding cycles.

[0086] In the following explanation, unless otherwise specified, "required time" refers to the time required from the start of the injection operation for injecting resin into the mold 20 by the screw 34 until the load LO exceeds the first threshold TH1.

[0087] The statistics calculation unit 88 calculates a statistical quantity ST based on multiple operation information INFs acquired during multiple molding cycles. For example, the statistics calculation unit 88 calculates the statistical quantity ST based on a predetermined number of operation information INFs acquired from a predetermined number of molding cycles prior to the last molding cycle to the last molding cycle.

[0088] The predetermined number may be instructed by the operator to the statistical calculation unit 88 via the control unit 74, or it may be pre-set by the manufacturer of the injection molding machine 10. The storage unit 76 may also store the statistical quantity ST calculated by the statistical calculation unit 88.

[0089] The statistic ST is, for example, a representative value of multiple required times. That is, the statistic calculation unit 88 may calculate the average, minimum, maximum, mode, or weighted median of multiple required times obtained in multiple molding cycles as the statistic ST. The average value can be any of the following: arithmetic mean, weighted mean, weighted harmonic mean, harmonic mean, trimmed mean, or mean sum of squares.

[0090] The operator may instruct the statistical calculation unit 88 via the control unit 74 to specify the type of value to be calculated as the statistical quantity ST, from among the mean, minimum, maximum, mode, or weighted median. Alternatively, the manufacturer of the injection molding machine 10 may pre-set the type of value to be calculated as the statistical quantity ST, from among the mean, minimum, maximum, mode, or weighted median of the required time.

[0091] Figure 5 is a time chart illustrating the time progression of the screw load LO (resin pressure) during the injection process of each molding cycle, for a molding cycle that is repeated three times.

[0092] In Figure 5, the vertical axis represents the load LO (resin pressure). The horizontal axis represents time. Figure 5 shows the first transition CYC1, the second transition CYC2, and the third transition CYC3. The first transition CYC1 shows the change in resin pressure during the injection process of the first molding cycle, out of three repeated molding cycles. The second transition CYC2 shows the change in resin pressure during the injection process of the second molding cycle, out of three repeated molding cycles. The third transition CYC3 shows the change in resin pressure during the injection process of the third molding cycle, out of three repeated molding cycles.

[0093] In Figure 5, the first transition CYC1, the second transition CYC2, and the third transition CYC3 are drawn superimposed on each other with reference to the start time t0 of the injection process for comparison. Time t1 indicates the point in the first molding cycle when the resin pressure reaches the first threshold TH1. The time required for the first molding cycle τ1 is the elapsed time from time t0 to time t1. Time t2 indicates the point in the second molding cycle when the resin pressure reaches the first threshold TH1. The time required for the second molding cycle τ2 is the elapsed time from time t0 to time t2. Time t3 indicates the point in the third molding cycle when the resin pressure reaches the first threshold TH1. The time required for the third molding cycle τ3 is the elapsed time from time t0 to time t3. The statistical quantity ST calculated by the statistical quantity calculation unit 88 using the three required times (τ1, τ2, τ3) in Figure 5 is, for example, ST = (τ1 + τ2 + τ3) / 3.

[0094] Furthermore, considering the possibility that outliers (abnormal values) may be accidentally included in multiple time intervals, it is preferable that the representative value be the mean, mode, or weighted median. This reduces the risk of selecting an outlier as the representative value (maximum or minimum value).

[0095] The range determination unit 90 determines the acceptable range AR of the operation information INF (required time). The acceptable range AR is determined based on the statistic ST (representative value). The range determination unit 90 determines the acceptable range AR by, for example, adding a predetermined offset to the representative value.

[0096] For example, the operation information acquisition unit 86 acquires the required time for each of the 1st to Mth molding cycles (M: a natural number, where M ≥ 2). The statistical calculation unit 88 calculates the average of the multiple required times acquired during the 1st to Mth molding cycles as a representative value. In this case, the range determination unit 90 calculates an upper limit greater than the representative value and a lower limit less than the representative value by adding a predetermined offset to the representative value. This determines the allowable range AR. The storage unit 76 may store the allowable range AR determined by the range determination unit 90.

[0097] The range determination unit 90 may use different offsets depending on the type of representative value. For example, the range determination unit 90 may use different offsets when the representative value is the maximum value and when the representative value is the mode.

[0098] Furthermore, for example, if the representative value is the maximum value, the range determination unit 90 may use that maximum value as the upper limit of the acceptable range AR. Similarly, if the representative value is the minimum value, the range determination unit 90 may use that minimum value as the lower limit of the acceptable range AR. In connection with this, the aforementioned statistical calculation unit 88 may calculate multiple types of statistical quantities ST (representative value) as needed.

[0099] Furthermore, the range determination unit 90 may determine only one of the upper limit and lower limit of the operation information INF. If only the upper limit is determined, the entire range below that upper limit is the acceptable range AR. If only the lower limit is determined, the entire range above that lower limit is the acceptable range AR.

[0100] The determination unit 92 determines the quality of the measured resin using the tolerance range AR based on the statistical quantity ST. The determination unit 92 determines the quality of the measured resin in a molding cycle based on a comparison between the tolerance range AR and the operation information INF acquired by the operation information acquisition unit 86 in a molding cycle performed after the tolerance range AR has been determined.

[0101] For example, the range determination unit 90 determines the acceptable range AR based on multiple required times obtained between the 1st to the Mth molding cycle. Then, in the Nth molding cycle, the operation information acquisition unit 86 acquires the required time (N: a natural number, where N > M). The determination unit 92 compares the acceptable range AR with the required time acquired in the Nth molding cycle.

[0102] In some cases, the time required for the Nth molding cycle falls within the acceptable range AR. In that case, the determination unit 92 determines that the resin condition in the Nth molding cycle is good. That is, compared to the resin condition measured in the 1st to Mth molding cycles, the resin condition measured in the Nth molding cycle is stable and does not vary.

[0103] On the other hand, the time required for the Nth molding cycle may not fall within the acceptable range AR. In that case, the determination unit 92 determines that the state of the resin in the Nth molding cycle is not good. That is, the state of the resin measured in the Nth molding cycle varies greatly and is not stable compared to the state of the resin measured in the 1st to Mth molding cycles.

[0104] The correction command unit 94 outputs a correction signal based on the determination result of the determination unit 92. The correction signal is a signal for correcting the weighing condition value CV. The correction command unit 94 outputs a correction signal to the control device 18 when the determination unit 92 determines that the condition of the resin is not good.

[0105] If the required time compared to the allowable range AR is greater than the allowable range AR, the correction command unit 94 outputs a correction signal indicating that the weighing condition value CV should be corrected to be smaller than the current weighing condition value CV.

[0106] In that case, the control device 18 corrects the metering condition value CV to be smaller than the current metering condition value CV based on the input correction signal. In other words, the control device 18 reduces at least one of the target temperature of the cylinder 26, the target rotational speed of the screw 34, and the target pressure of the resin to a value smaller than the current value based on the input correction signal.

[0107] The reason the time required for the Nth molding cycle exceeds the allowable time is that the viscosity of the resin in the Nth molding cycle is excessively low compared to the viscosity of the resin in the 1st to Mth molding cycles. In other words, because the viscosity of the resin metered in the Nth metering step is low, it takes a long time for the load LO to reach the first threshold TH1 in the Nth injection step.

[0108] Therefore, if the time required for the Nth molding cycle exceeds the allowable time, the metering condition value CV is corrected as described above so that the viscosity of the resin in the (N+1)th and subsequent molding cycles is greater than the viscosity of the resin in the Nth molding cycle. This reduces variations in the state of the resin in the (N+1)th and subsequent molding cycles.

[0109] On the other hand, if the required time compared to the allowable range AR is smaller than the allowable range AR, the correction command unit 94 outputs a correction signal indicating that the weighing condition value CV should be corrected to be larger than the current weighing condition value CV.

[0110] In that case, the control device 18 corrects the metering condition value CV to be greater than the current metering condition value CV based on the input correction signal. In other words, based on the input correction signal, the control device 18 increases at least one of the following values: the target temperature of the cylinder 26, the target rotational speed of the screw 34, and the target pressure of the resin, to a value greater than the current value.

[0111] The reason why the time required for the Nth molding cycle is less than the allowable time is that the viscosity of the resin in the Nth molding cycle is excessively high compared to the viscosity of the resin in the 1st to Mth molding cycles. In other words, because the viscosity of the resin metered in the Nth metering step is high, the load LO reaches the first threshold TH1 in a short time during the Nth injection step.

[0112] Therefore, if the time required for the Nth molding cycle is less than the allowable time, the metering condition value CV is corrected as described above so that the viscosity of the resin in the (N+1)th and subsequent molding cycles is lower than the viscosity of the resin in the Nth molding cycle. This reduces variations in the state of the resin in the (N+1)th and subsequent molding cycles.

[0113] The correction command unit 94 may include the correction amount for the metering condition value CV in the correction signal. In that case, the control device 18 corrects the metering condition value CV based on the correction amount included in the correction signal.

[0114] The correction amount for the measurement condition value CV is determined, for example, according to the amount of deviation from the tolerance range AR over a predetermined period of time. In this case, the correction command unit 94 may determine the correction amount using, for example, a data table in which multiple correction amounts are stored according to the amount of deviation. However, the correction amount may be a fixed amount that is not limited to the amount of deviation from the tolerance range AR over a predetermined period of time.

[0115] The display control unit 96 controls the display unit 72 to display various data stored in the storage unit 76 on the display screen 72d. The display control unit 96 displays various data on the display screen 72d, for example, in response to instructions from the operator.

[0116] Furthermore, it is preferable that the display control unit 96 controls the display unit 72 to display the determination result of the determination unit 92 on the display screen 72d. This allows the operator to know whether the resin is in good or bad condition.

[0117] The operator may instruct the determination device 70 (correction command unit 94) whether or not to correct the weighing condition value CV based on the determination result displayed on the display screen 72d. Alternatively, the operator may instruct the determination device 70 (correction command unit 94) by the amount of correction for the weighing condition value CV based on the determination result displayed on the display screen 72d.

[0118] Figure 6 is a flowchart illustrating the flow of the determination method according to the embodiment.

[0119] The determination device 70 can execute the determination method illustrated in Figure 6. This determination method includes a load acquisition step S1, a load determination step S2, an operation information acquisition step S3, and a processing selection step S4. The determination method in Figure 6 further includes a calculation feasibility determination step S5, a statistical calculation step S6, a range determination step S7, a state determination step (determination step) S8, and a correction command step S9.

[0120] In the load acquisition step S1, the load acquisition unit 82 acquires the load LO of the screw 34. This load LO is the load applied to the screw 34 in accordance with the injection operation performed by the screw 34 during the injection process. The load LO is, for example, the pressure of the resin.

[0121] The load LO increases as the injection operation is performed. In the load determination step S2, the operation information acquisition unit 86, for example, determines whether the load LO exceeds the first threshold TH1.

[0122] The first threshold TH1 is determined by the threshold determination unit 84 based on the type of screw 34 and the type of resin before the load determination step S2 is started. The timing of when the threshold determination unit 84 determines the first threshold TH1 is not particularly limited, as long as it is before the load determination step S2 is performed. Therefore, the threshold determination unit 84 may determine the first threshold TH1, for example, before the injection molding machine 10 starts operation.

[0123] If the load LO does not exceed the first threshold TH1 (LO ≤ TH1), the load acquisition step S1 continues. If the load LO exceeds the first threshold TH1 (LO > TH1), the operation information acquisition step S3 is started.

[0124] In the operation information acquisition step S3, the operation information acquisition unit 86 acquires operation information INF (required time). The acquired operation information INF is stored in the storage unit 76.

[0125] In the processing selection step S4, the range determination unit 90 determines, for example, whether the acceptable range AR has already been determined. This determination is made by checking whether the storage unit 76 has stored the acceptable range AR.

[0126] If the acceptable range AR is not yet determined (S4: NO), the calculation feasibility determination step S5 is started. If the acceptable range AR has already been determined (S4: YES), the status determination step S8 is started.

[0127] In calculation feasibility determination step S5, the statistics calculation unit 88, for example, determines whether or not the statistics quantity ST can be calculated. In the example shown in Figure 6, the statistics quantity ST is calculated using a predetermined number of operation information INF. Therefore, the statistics calculation unit 88 determines that the statistics quantity ST can be calculated when the number of operation information INF stored in the storage unit 76 reaches a predetermined number.

[0128] If it is possible to calculate the statistic ST (S5:YES), the statistic calculation step S6 is started. If it is not possible to calculate the statistic ST (S5:NO), the flow from the load acquisition step S1 to the calculation feasibility determination step S5 is executed again in accordance with the injection molding machine 10 starting the next molding cycle. Since the operation information acquisition step S3 is performed each time a molding cycle is executed, the number of acquired operation information INFs will eventually reach a predetermined number.

[0129] In the statistical calculation step S6, the statistical calculation unit 88 calculates the statistical quantity ST. In the example shown in Figure 6, the calculated statistical quantity ST is a representative value of a predetermined number of operation information INF (required time). The calculated statistical quantity ST is stored in the storage unit 76.

[0130] In the range determination step S7, the range determination unit 90 determines the acceptable range AR based on the statistic ST. The determined acceptable range AR is stored in the storage unit 76.

[0131] In the state determination step S8, the determination unit 92 determines whether the resin is in good or bad condition based on the tolerance range AR and the operation information INF.

[0132] If the operation information INF (required time) falls within the acceptable range AR, the determination unit 92 determines that the resin is in good condition. In this case, the determination method shown in Figure 6 is terminated. However, as long as the injection molding machine 10 repeats the molding cycle, the determination device 70 may repeatedly execute the determination method shown in Figure 6 (RETURN → START).

[0133] If the required time included in the operation information INF deviates from the allowable range AR, the determination unit 92 determines that the resin is not in good condition. In this case, the correction command step S9 is started.

[0134] In the correction command step S9, the correction command unit 94 outputs a correction signal to the control device 18. This allows the control device 18 to correct the metering condition value CV based on the correction signal.

[0135] The determination method shown in Figure 6 ends when the correction command step S9 is completed. However, as mentioned above, the injection molding machine 10 can repeat the molding cycle even after the determination method shown in Figure 6 has ended. In the molding cycle executed after the correction command step S9, control is performed based on the corrected metering condition value CV.

[0136] As described above, this embodiment makes it possible to determine whether the condition of the measured resin is good or bad. Moreover, according to this embodiment, if it is determined that the condition of the resin is not good, the measurement condition value CV can be automatically corrected. This allows for the continuation of stable production, thus improving productivity. In addition, the operator of the injection molding machine 10 does not need to adjust the measurement condition value CV, thus reducing the workload on the operator.

[0137] Furthermore, recycled resins and fiber-reinforced resins are used as resins in the production of molded products. Recycled resins are resins that contain recycled materials. Fiber-reinforced resins are resins that contain reinforcing fibers as a material. Reinforcing fibers are, for example, glass fibers. The physical properties of recycled resins and fiber-reinforced resins are not as stable as those of virgin materials made from new materials. Therefore, when the injection molding machine 10 produces molded products using recycled resins, fiber-reinforced resins, etc., the state of the resin accumulated in the metering area during the metering process may fluctuate during production. According to this embodiment, even when production is carried out using recycled resins, fiber-reinforced resins, etc., the judgment device 70 can determine whether the state of the resin metered during production is good or bad. In addition, the injection molding machine 10 can automatically correct the metering condition value CV based on the correction signal output according to the judgment result. Therefore, even when production is carried out using recycled resins, fiber-reinforced resins, etc., the injection molding machine 10 can continue to produce good molded products.

[0138] [Differentiation] The following describes modifications according to the above embodiment. However, descriptions that overlap with the above embodiment will be omitted as much as possible in the following description. Elements already described in the embodiment will be denoted by the same reference numerals as in the embodiment unless otherwise specified.

[0139] (Variation 1) The operation information INF is not limited to the required time. For example, the operation information acquisition unit 86 may include in the operation information INF the amount of movement of the screw 34 from the time the screw 34 starts the injection operation to inject resin into the mold 20 until the load LO exceeds the first threshold TH1.

[0140] Furthermore, if the screw 34 rotates during the injection process, the operation information acquisition unit 86 may include in the operation information INF the amount of rotation of the screw 34 from the time the screw 34 starts the injection operation to inject resin into the mold 20 until the load LO exceeds the first threshold TH1.

[0141] Furthermore, the above-mentioned case in which the screw 34 rotates during the injection process includes not only the case in which the control device 18 controls the rotation of the first motor 52a to rotate the first shaft 60a, but also the case in which the excitation of the first motor 52a is released and the first shaft 60a is in a free state. In other words, when the first shaft 60a is in a free state during the injection process, the first shaft 60a rotates in accordance with the viscous resistance of the resin acting on the flight portion 42 of the screw 34.

[0142] According to this modified example, the operation information acquisition unit 86 includes at least one of the following in the operation information INF: the amount of movement of the screw 34, the amount of rotation, and the time required, from the time the screw 34 starts its injection operation until the load LO exceeds the first threshold TH1.

[0143] The statistical calculation unit 88 calculates at least one of the above-mentioned statistical quantities ST of required time, ST of movement, and ST of rotation, according to the contents of the operation information INF. The operator may instruct the determination device 70 (operation information acquisition unit 86, statistical calculation unit 88) which of the above-mentioned required time, movement, and rotation to use to calculate the statistical quantity ST. The operator's instruction is given, for example, via the operation unit 74. The manufacturer of the injection molding machine 10 may also pre-set in the determination device 70 which of the above-mentioned required time, movement, and rotation to use to calculate the statistical quantity ST.

[0144] According to this modified example, multiple statistical quantities ST are calculated. The range determination unit 90 may determine multiple tolerance ranges AR according to each statistical quantity ST. For example, the range determination unit 90 may determine a tolerance range AR based on representative values ​​of multiple displacement amounts and a tolerance range AR based on representative values ​​of multiple rotation amounts.

[0145] If multiple tolerance ranges AR are determined, the determination unit 92 may use each tolerance range AR to determine whether the resin is in good or bad condition.

[0146] For example, an acceptable range AR for the required time is determined based on the time taken between each molding cycle from the 1st to the Mth. The determination unit 92 compares the time taken in the Nth molding cycle with the acceptable range AR for the required time to determine whether the resin state in the Nth molding cycle is good or bad.

[0147] Furthermore, an acceptable range AR for the amount of movement is determined based on the amount of movement of the screw 34 obtained between each molding cycle from the 1st to the Mth cycle. The determination unit 92 also compares the amount of movement obtained in the Nth molding cycle with the acceptable range AR for the amount of movement to further determine whether the resin state in the Nth molding cycle is good or bad.

[0148] Furthermore, an acceptable range AR for the amount of rotation of the screw 34 is determined based on the amount of rotation of the screw 34 obtained between each molding cycle from the 1st to the Mth cycle. The determination unit 92 also compares the amount of rotation obtained in the Nth molding cycle with the acceptable range AR for the amount of rotation to further determine whether the resin state in the Nth molding cycle is good or bad.

[0149] In the example above, the quality of the resin state after the Nth molding cycle is determined by three types of operational information INF: the time required, the amount of movement of the screw 34, and the amount of rotation of the screw 34. In this case, the three determination results regarding the resin state after the Nth molding cycle may differ from each other.

[0150] For example, in a determination using the tolerance range AR for the required time and a determination using the tolerance range AR for the amount of movement, the resin condition in the Nth molding cycle may be determined to be good. On the other hand, in a determination using the tolerance range AR for the amount of rotation, the resin condition in the Nth molding cycle may be determined to be poor.

[0151] When multiple judgment results regarding the state of the resin in the same molding cycle differ from each other, the final judgment result is determined, for example, by majority vote. For example, in the above example, the state of the resin in the Nth molding cycle is judged for three types of operation information INF. Also, the number of times the state of the resin in the Nth molding cycle is judged to be good is two out of the three types of operation information INF, which is a majority. In this case, the judgment unit 92 ultimately determines that the state of the resin in the Nth molding cycle is good.

[0152] However, if multiple judgment results obtained regarding the state of the resin in the same molding cycle differ from each other, it is more preferable for the judgment unit 92 to determine that the state of the resin is good only if it was determined that the state of the resin is good in all of those multiple judgments.

[0153] For example, in the above example, the state of the resin in the Nth molding cycle is determined based on three types of operational information INF. In the determination of one of these three types of operational information INF (rotation amount), it is determined that the state of the resin in the Nth molding cycle is not good. In this case, the determination unit 92 ultimately determines that the state of the resin in the Nth molding cycle is not good.

[0154] The determination unit 92 determines that the resin is in good condition only if it has determined that the resin is in good condition in all of the multiple determinations. This reduces the risk of overlooking resin that is in poor condition.

[0155] (Modification 2) The determination unit 92 may determine whether the state of the resin measured in that molding cycle is good or bad based on a comparison between the allowable range AR and the operation information INF acquired by the operation information acquisition unit 86 in the molding cycle performed before the allowable range AR was determined.

[0156] For example, the range determination unit 90 determines the allowable range AR based on a plurality of required times acquired during the first to M-th molding cycles. The determination unit 92 may compare the allowable range AR with the required time acquired in the L-th molding cycle performed before the M-th time (L: natural number, provided that L ≤ M). Thereby, it is possible to determine whether the resin state measured in the first to M-th molding cycles used for calculating the allowable range AR is good or bad.

[0157] (Modification Example 3) In the embodiment, an example of calculating the statistic ST based on a plurality of required times acquired during the first to M-th molding cycles has been described. However, the plurality of required times may not include the required time acquired in the first molding cycle.

[0158] For example, the statistic calculation unit 88 may calculate the statistic ST based on a plurality of required times acquired during the K-th to M-th molding cycles (K: natural number, provided that 2 ≤ K < M). The allowable range AR is determined based on a plurality of required times acquired during the K-th to M-th molding cycles. Immediately after starting the operation of the injection molding machine 10, the operating state may not be stable. In that regard, according to this modification example, the statistic ST can be calculated excluding the required time obtained in the molding cycle performed while the operating state of the injection molding machine 10 is not stable.

[0159] (Modification Example 4) The operator may instruct the determination device 70 with the first threshold value TH1. In that case, the threshold value determination unit 84 may be omitted. However, the operator may change the first threshold value TH1 determined by the threshold value determination unit 84 via the operation unit 74.

[0160] The operator inputs the first threshold value TH1 to the determination device 70 via, for example, the operation unit 74. The operation information acquisition unit 86 acquires the operation information INF based on a comparison between the input first threshold value TH1 and the load LO applied to the screw 34. <^

[0161] (Modification Example 5) The load acquisition unit 82 may acquire at least one of the torque of the first motor 52a (first torque) and the torque of the second motor 52b (second torque) as the load LO applied to the screw 34. The first threshold value TH1 compared with the torque of the first motor 52a and the first threshold value TH1 compared with the torque of the second motor 52b may be different.

[0162] The operation information acquisition unit 86 may acquire the shorter of the time required for the first torque to reach the first threshold TH1 and the time required for the second torque to reach the first threshold TH1 as operation information INF.

[0163] However, the operation information acquisition unit 86 may acquire the longer of the time required for the first torque to reach the first threshold TH1 and the time required for the second torque to reach the first threshold TH1 as operation information INF.

[0164] The first torque may also be the disturbance load torque of the first motor 52a. Similarly, the second torque may be the disturbance load torque of the second motor 52b. In that case, the disturbance load torque of the first motor 52a or the second motor 52b may be estimated using a disturbance estimation observer.

[0165] (Experimental variation 6) Figure 7 is a diagram showing the configuration of the determination device 701(70) according to modified example 6.

[0166] The determination device 701 differs from the embodiment (see also Figure 3) in that it includes a control limiting unit 98 instead of a correction command unit 94.

[0167] The control limiting unit 98 outputs a predetermined control signal based on the determination result of the determination unit 92. This control signal is a signal to limit the operation of the injection molding machine 10. The control limiting unit 98 outputs a control signal to the control device 18 when the determination unit 92 determines that the resin condition is not good.

[0168] When a control signal is input from the control limiting unit 98, the control device 18 stops the operation of the injection molding machine 10. This temporarily suspends the production of molded products if it is determined that the resin is not in good condition. While the production of molded products is suspended, the operator can inspect the injection molding machine 10, adjust the metering condition value CV, etc.

[0169] The determination device 701 may include both a control limiting unit 98 and a correction command unit 94. In this case, the correction command unit 94 and the control limiting unit 98 may be used interchangeably, for example, based on the amount of deviation of the operation information INF (required time) from the allowable range AR.

[0170] For example, if the above deviation amount is less than a predetermined deviation amount, the correction command unit 94 outputs a correction signal to correct the metering condition value CV. In this case, the control limiting unit 98 does not output a control signal. On the other hand, if the above deviation amount is greater than or equal to a predetermined deviation amount, the control limiting unit 98 outputs a control signal to restrict the operation of the injection molding machine 10. In this case, the correction command unit 94 does not output a correction signal. This makes it possible to suppress an increase in the frequency of the injection molding machine 10's operation being restricted.

[0171] (Example 7) Figure 8 is a configuration diagram of the determination device 702(70) according to the modified example 7.

[0172] The statistical calculation unit 88 may calculate the degree of variance based on multiple operational information INFs as the statistical quantity ST. For example, the statistical calculation unit 88 may calculate the variance, deviation, or coefficient of variation based on multiple operational information INFs. The deviation is, for example, the standard deviation. However, the statistical calculation unit 88 may calculate the mean deviation as the deviation.

[0173] The variance indicates the degree of variation among multiple operational information INF values. For example, if the operational information INF includes the required time, the variance indicates the degree of variation in the required time across multiple molding cycles.

[0174] The determination unit 92 compares the degree of dispersion with a predetermined threshold value (second threshold value) TH2. The second threshold value TH2 is stored in advance in the storage unit 76. The second threshold value TH2 is determined in advance based on experiments. Similar to the first threshold value TH1, the second threshold value TH2 may be determined according to the type of the screw 34 and the type of the resin.

[0175] When the degree of dispersion is less than or equal to the second threshold value TH2, the determination unit 92 determines that the state of the resin is good. On the other hand, when the degree of dispersion exceeds the second threshold value TH2, the determination unit 92 determines that the state of the resin is not good.

[0176] Note that the resin determined based on the degree of dispersion is the resin measured in the molding cycle in which a plurality of operation information INF for calculating the degree of dispersion is acquired.

[0177] For example, based on a plurality of operation information INF acquired during the Kth to Mth molding cycles (K: natural number, where 1 ≤ K < M), the degree of dispersion is calculated. The determination unit 92 uses the degree of dispersion to determine whether the state of the resin measured during the Kth to Mth molding cycles is good or not. When the degree of dispersion is less than or equal to the second threshold value TH2, it is determined that the state of the resin measured in all the Kth to Mth molding cycles is good. When the degree of dispersion exceeds the second threshold value TH2, it is determined that the state of the resin measured in all the Kth to Mth molding cycles is not good.

[0178] FIG. 9 is a flowchart illustrating the flow of the determination method according to the seventh modification.

[0179] The determination device 702 can execute the determination method illustrated in FIG. 9. The determination method includes a load acquisition step S1, a load determination step S2, an operation information acquisition step S3, a calculation availability determination step S5, a statistic calculation step S6, a state determination step S8, and a correction command step S9.

[0180] The explanations of the load acquisition step S1, load determination step S2, operation information acquisition step S3, calculation feasibility determination step S5, and correction command step S9 are omitted (see Embodiment).

[0181] Step S6 of the statistical calculation is the same as in the embodiment in that the statistical calculation unit 88 calculates the statistical quantity ST. However, in step S6 of the statistical calculation in Figure 9, the degree of variance is calculated as the statistical quantity ST.

[0182] The state determination step S8 is the same as in the embodiment in that the determination unit 92 determines whether the state of the resin is good or bad using the statistical quantity ST. However, the statistical quantity ST used by the determination unit 92 in the statistical quantity calculation step S6 in Figure 9 is the degree of dispersion, not a representative value. Also, in the state determination step S8 in Figure 9, the state of the resin measured between the start of the determination method and the start of the statistical quantity calculation step S6 is determined.

[0183] The statistical calculation unit 88 may recalculate the degree of dispersion each time the molding cycle is repeated, after having calculated the degree of dispersion once.

[0184] For example, the statistical calculation unit 88 calculates the degree of dispersion based on multiple time intervals obtained between the Kth to Mth molding cycles. This degree of dispersion is used to determine the quality of the resin measured during the Kth to Mth molding cycles.

[0185] Subsequently, the statistical calculation unit 88 recalculates the variance based on multiple time intervals obtained between the (K+1)th to (M+1)th molding cycles. This variance can be used to determine the quality of the resin measured during the (K+1)th to (M+1)th molding cycles.

[0186] However, the state of the resin measured during the (K+1)th to Mth molding cycles has already been determined once. In this case, the determination based on the recalculated dispersion degree is performed as a double check for the range of the (K+1)th to Mth molding cycles. Alternatively, the determination result based on the recalculated dispersion degree may be ignored for the range of the (K+1)th to Mth molding cycles.

[0187] In the example above, the variance is recalculated each time the molding cycle from the Mth onward is repeated. In other words, in the example above, the variance is calculated at a rate of one cycle. However, the variance can be calculated at a rate of two cycles or more.

[0188] (Variation 8) The statistical calculation unit 88 may calculate both the representative value and the variance value (see modified example 7). The determination unit 92 may determine the quality of the resin based on both the representative value and the variance value.

[0189] For example, the statistical calculation unit 88 calculates multiple deviations (degree of variance) of required times obtained between the Kth to Mth molding cycles. The determination unit 92 uses the deviations to determine whether the resin measured between the Kth to Mth molding cycles is of good or bad condition.

[0190] Furthermore, the statistical calculation unit 88 calculates the average value (representative value) of multiple required times obtained between the Kth to Mth molding cycles. The range determination unit 90 determines the tolerance range AR based on this average value. The judgment unit 92 uses the tolerance range AR to determine whether the resin measured in the Nth molding cycle is of good or bad condition.

[0191] Furthermore, the determination unit 92 may perform both a determination based on the degree of dispersion and a determination based on representative values ​​in order to determine whether the resin measured in the same molding cycle is of good or bad condition.

[0192] For example, a deviation and an average value are calculated based on multiple time intervals obtained between the 1st to Mth molding cycles. An acceptable range AR is then determined based on the average value. The determination unit 92 determines the state of the resin measured during the 1st to Mth molding cycles based on the deviation. The determination unit 92 also determines the state of the resin measured during the Lth molding cycle based on the acceptable range AR (L: a natural number, where L ≤ M). Thus, the state of the resin during the Lth molding cycle is determined based on both the degree of dispersion and the representative value.

[0193] Here, there is a possibility that the judgment result based on the degree of dispersion and the judgment result based on the representative value may differ. In that case, it is preferable that the judgment unit 92 finally determines that the resin condition of the L-th molding cycle is good only if it can determine that the resin condition of the L-th molding cycle is good based on both the judgment based on the degree of dispersion and the judgment based on the representative value. This reduces the risk of overlooking resin that is in poor condition.

[0194] (Extreme variation 9) The control device 18 may control the second motor 52b to perform a suck-back, which moves the screw 34 backward from the metering position, in order to reduce the pressure of the resin.

[0195] (Variation 10) The threshold table TB may store multiple thresholds depending not only on the type of screw 34 and the type of resin, but also on the type of nozzle 32.

[0196] (Variation 11) The method in which the axis LA of cylinder 26 and the axis of screw 34 coincide is also called the inline (inline screw) method. An injection molding machine 10 to which the inline method is applied is also called an inline injection molding machine. The injection device (14) of an inline injection molding machine (10) is easier to maintain than the injection device of other types.

[0197] However, the determination device 70 may be provided in an injection molding machine 10 that is not of the in-line type. An example of a non-in-line type is a pre-plasticization type.

[0198] (Example 12) The determination device 70 may be incorporated into the control device 18. In this case, the control device 18 and the determination device 70 are provided as a single integrated electronic device.

[0199] (Example 13) Figure 10 is a diagram showing the configuration of the injection molding system SYS1(SYS) according to modified example 13.

[0200] The injection molding system SYS1 comprises a plurality of injection molding machines 10 and a control device 100. The number of injection molding machines 10 provided in the injection molding system SYS1 is not particularly limited.

[0201] The control device 100 is, for example, an electronic device for managing multiple injection molding machines 10. The control device 100 is communicatively connected to the control devices 18 (181, 182, 183, ...) of each injection molding machine 10. The control device 100 communicates with the multiple control devices 18 via a predetermined network. The operator can issue instructions to the multiple control devices 18 simultaneously via the control device 100.

[0202] The determination device 70 may be incorporated into the control device 100. In this case, the determination device 70 and the control device 100 are provided to the operator as a single integrated electronic device.

[0203] The determination device 70 acquires multiple operation information INFs from each of the multiple injection molding machines 10. For example, the determination device 70 acquires multiple operation information INFs from each of the control devices 181, 182, and 183 via a predetermined network.

[0204] Furthermore, the determination device 70 determines the quality of the measured resin for each injection molding machine 10. For example, the determination device 70 determines the quality of the resin measured in an injection molding machine 10 equipped with the control device 181 based on a plurality of operation information INFs obtained from the control device 181. Similarly, the determination device 70 determines the quality of the resin measured in an injection molding machine 10 equipped with the control device 182 (183) based on a plurality of operation information INFs obtained from the control device 182 (183).

[0205] According to this modified example, the quality of the resin measured in each of the multiple injection molding machines 10 can be determined using a single electronic device (determination device 70).

[0206] Figure 11 is a configuration diagram of another injection molding system SYS2(SYS) related to modified example 13.

[0207] The determination device 70 may be incorporated into one of several control devices provided in the injection molding system SYS (see also Modification 12).

[0208] For example, the injection molding system SYS2 includes at least three control devices 18 (185, 186, 187, ...). The determination device 70 is incorporated into, for example, control device 185. The determination device 70 communicates with the other control devices 18 (187, 188) via a predetermined network. This allows the determination device 70 to determine the quality of the resin measured not only in the injection molding machine 10 equipped with control device 185, but also in, for example, the injection molding machine 10 equipped with control device 186 and the injection molding machine 10 equipped with control device 187.

[0209] [Invention obtained from the embodiment] The inventions that can be understood from the above embodiments and modified examples are described below.

[0210] <First Invention> The first invention is a determination device (70) for determining the quality of the condition of a resin measured by an injection molding machine (10) comprising a cylinder (26) and a screw (34) for injecting the resin measured in the cylinder into a mold (20), the device comprising a load acquisition unit (82) that acquires the load (LO) applied to the screw in accordance with the injection of the resin from the cylinder into the mold in multiple molding cycles, and in multiple molding cycles, when the screw starts the injection operation to inject the resin into the mold The determination device comprises: an operation information acquisition unit (86) that acquires operation information (INF) including at least one of the amount of movement of the screw, the amount of rotation, and the required time until the load exceeds a first threshold (TH1); a statistical quantity calculation unit (88) that calculates at least one statistical quantity (ST) among the amount of movement, the amount of rotation, and the required time based on a plurality of operation information acquired in a plurality of molding cycles; and a determination unit (92) that determines whether the state of the measured resin is good or bad based on the statistical quantity.

[0211] This allows for the determination of the quality of the measured resin.

[0212] The load acquisition unit may acquire at least one of the first torque of the first motor (52a) that rotates the screw and the second torque of the second motor (52b) that advances the screw as the load. This allows the load on the screw to be detected based on the current torque sensor originally provided in the motor, thereby suppressing an increase in equipment costs for load detection.

[0213] The load acquisition unit may acquire the pressure of the resin in the cylinder as the load. This allows the screw load to be detected based on the pressure sensor originally installed in the injection molding machine, thereby suppressing the increase in equipment costs for load detection.

[0214] The first invention further comprises a threshold determination unit (84) that determines the first threshold based on a threshold table (TB) which stores a plurality of first thresholds according to at least one of a plurality of types of screws and a plurality of types of resin, and the operation information acquisition unit may acquire the operation information using the first threshold determined by the threshold determination unit. As a result, operation information is acquired based on appropriate thresholds according to the screws, resin, etc. used in injection molding.

[0215] The first invention may further include an operating unit (74) for the operator to specify the first threshold value. This allows the operator to set the first threshold value arbitrarily.

[0216] The statistical calculation unit calculates at least one of the dispersion degrees of multiple movement amounts, the dispersion degrees of multiple rotation amounts, and the dispersion degrees of multiple required times based on the acquired operation information. If the calculated dispersion degree exceeds a second threshold (TH2), the determination unit may determine that the condition of the resin measured during multiple molding cycles is not good. This makes it possible to determine whether the condition of the measured resin is good or bad.

[0217] The statistical calculation unit calculates at least one of a plurality of representative values ​​of the displacement, a plurality of representative values ​​of the rotation, and a plurality of representative values ​​of the required time. The determination device further includes a range determination unit (90) that determines an acceptable range (AR) based on the calculated representative values. In the molding cycle after the acceptable range has been determined, the determination unit may determine the quality of the measured resin based on the operation information and the acceptable range. This makes it possible to determine the quality of the measured resin.

[0218] The injection molding machine includes a control device (18) that controls the injection molding machine to measure the resin based on a metering condition value (CV) which includes at least one of the target temperature of the cylinder, the target rotational speed of the screw, and the target pressure of the resin. The determination device further includes a correction command unit (94) that outputs a correction signal for correcting the metering condition value based on the determination result of the determination unit. The control device corrects the metering condition value based on the correction signal, and the correction signal is a signal to correct the metering condition value to be smaller than the current metering condition value if the amount of movement, the amount of rotation, or the required time is larger than the allowable range, or a signal to correct the metering condition value to be larger than the current metering condition value if the amount of movement, the amount of rotation, or the required time is smaller than the allowable range. As a result, the metering condition value is automatically corrected so that the quality of the molded product is stable.

[0219] The first invention further includes a control limiting unit (98) that outputs a predetermined control signal to the control device of the injection molding machine when the determination unit determines that the condition of the resin is not good, and the predetermined control signal may be a signal to limit the operation of the injection molding machine. As a result, the operation of the injection molding machine is automatically limited when there is a risk that the quality of the molded product will not be stable.

[0220] The first invention may further include a display control unit (96) that controls a display device (72) to display information indicating the determination result of the determination unit on the display device. This makes it possible to inform the operator of the determination result regarding the quality of the resin.

[0221] The first invention may determine the quality of the measured resin for each injection molding machine by acquiring the load and a plurality of operation information from each of the plurality of injection molding machines. This makes it possible to determine the quality of the resin measured at each of the plurality of injection molding machines using a single determination device.

[0222] The determination device may be incorporated into a control device (100) that manages multiple injection molding machines. This allows a single determination device (control device) to determine whether the resin measured by each of the multiple injection molding machines is of good or bad condition.

[0223] <Second Invention> The second invention is a determination method for determining the quality of the state of a resin measured in an injection molding machine (10) which includes a cylinder (26) and a screw (34) for injecting the resin measured in the cylinder into a mold (20), the determination method comprising: a load acquisition step (S1) for acquiring the load (LO) applied to the screw in accordance with the injection of the resin from the cylinder into the mold in a plurality of molding cycles; an operation information acquisition step (S3) for acquiring operation information (INF) in a plurality of molding cycles, which includes at least one of the amount of movement, rotation, and time required of the screw from the time the screw starts the injection operation to inject the resin into the mold until the load exceeds a threshold; a statistical quantity calculation step (S6) for calculating at least one statistical quantity (ST) of the amount of movement, rotation, and time required based on a plurality of operation information acquired in a plurality of molding cycles; and a determination step (S8) for determining the quality of the state of the measured resin based on the statistical quantity.

[0224] This allows for the determination of the quality of the measured resin. [Explanation of symbols]

[0225] 10…Injection molding machine 18…Control device 20…Mold 26…Cylinder 34...Screw 52a...First motor 52b...Second motor 70...Determination device 72...Display section (display device) 74...Operation section 82...Load acquisition unit 84...Threshold determination unit 86...Operation information acquisition unit 88...Statistics calculation unit 90... Range determination unit 92... Judgment unit 94...Correction command unit 96...Display control unit 98...Control limiting unit 100...Management device AR... Acceptable range INF... Operating information LO...Load ST...Statistics TB...Threshold Table TH1...First Threshold TH2…Second threshold

Claims

1. A determination device for determining the quality of the resin measured in an injection molding machine, which comprises a cylinder and a screw for injecting the resin measured in the cylinder into a mold, A load acquisition unit that acquires the load applied to the screw in accordance with the injection of the resin from the cylinder into the mold during multiple molding cycles, An operation information acquisition unit acquires operation information in multiple molding cycles, including at least one of the amount of movement of the screw, the amount of rotation, and the time required, from the time the screw starts the injection operation to inject the resin into the mold until the load exceeds a first threshold. A statistical calculation unit calculates at least one statistical quantity among the amount of movement, the amount of rotation, and the required time based on the operation information obtained in the multiple molding cycles, A determination unit that determines whether the measured resin is in good or bad condition based on the aforementioned statistical quantity, Equipped with, The statistical calculation unit calculates at least one of the variances of multiple movement amounts, multiple rotation amounts, and multiple required times based on the acquired operation information. A determination device in which, if the calculated dispersion exceeds a second threshold, the determination unit determines that the condition of the resin measured during multiple molding cycles is not good.

2. A determination device according to claim 1, The statistical calculation unit calculates at least one of the following: a representative value of a plurality of displacement amounts, a representative value of a plurality of rotation amounts, and a representative value of a plurality of required times. The determination device further comprises a range determination unit that determines an acceptable range based on the calculated representative value, In the molding cycle after the tolerance range has been determined, the determination unit determines whether the state of the measured resin is good or bad based on the operation information and the tolerance range, in the determination device.

3. A determination device for determining the quality of the state of a resin measured in an injection molding machine, the machine comprising a cylinder and a screw for injecting the resin measured in the cylinder into a mold, A load acquisition unit that acquires the load applied to the screw in accordance with the injection of the resin from the cylinder into the mold during multiple molding cycles, An operation information acquisition unit acquires operation information in multiple molding cycles, including at least one of the amount of movement of the screw, the amount of rotation, and the time required, from the time the screw starts the injection operation to inject the resin into the mold until the load exceeds a first threshold. A statistical calculation unit calculates at least one statistical quantity among the amount of movement, the amount of rotation, and the required time based on the operation information obtained in the multiple molding cycles, A determination unit that determines whether the measured resin is in good or bad condition based on the aforementioned statistical quantity, Equipped with, The statistical calculation unit calculates at least one of the following: a representative value of a plurality of displacement amounts, a representative value of a plurality of rotation amounts, and a representative value of a plurality of required times. The determination device further comprises a range determination unit that determines an acceptable range based on the calculated representative value, In the molding cycle after the tolerance range has been determined, the determination unit determines whether the state of the measured resin is good or bad based on the operation information and the tolerance range. The injection molding machine includes a control device that controls the injection molding machine to measure the resin based on a metering condition value that includes at least one of the target temperature of the cylinder, the target rotational speed of the screw, and the target pressure of the resin. The determination device further comprises a correction command unit that outputs a correction signal for correcting the metering condition value based on the determination result of the determination unit, The control device corrects the measurement condition value based on the correction signal, The correction signal is, If the amount of movement, the amount of rotation, or the required time is greater than the allowable range, the signal indicates that the measurement condition value should be corrected to be smaller than the current measurement condition value. A determination device that, if the amount of movement, the amount of rotation, or the required time is smaller than the allowable range, signals that the measurement condition value should be increased from the current measurement condition value.

4. A determination device according to claim 3, The statistical calculation unit calculates at least one of the variances of multiple movement amounts, multiple rotation amounts, and multiple required times based on the acquired operation information. A determination device in which, if the calculated dispersion exceeds a second threshold, the determination unit determines that the condition of the resin measured during multiple molding cycles is not good.

5. A determination device according to any one of claims 1 to 4, The load acquisition unit is a determination device that acquires at least one of the first torque of the first motor that rotates the screw and the second torque of the second motor that advances the screw as the load.

6. A determination device according to any one of claims 1 to 4, The load acquisition unit is a determination device that acquires the pressure of the resin inside the cylinder as the load.

7. A determination device according to any one of claims 1 to 4, The threshold determination unit further comprises a threshold determination unit that determines the first threshold based on a threshold table in which a plurality of first thresholds are stored according to at least one of the plurality of types of screws and the plurality of types of resin, The operation information acquisition unit is a determination device that acquires the operation information using the first threshold determined by the threshold determination unit.

8. A determination device according to any one of claims 1 to 4, A determination device further comprising an operating unit for an operator to specify the first threshold value.

9. A determination device according to any one of claims 1 to 4, The determination unit further comprises a control limiting unit that outputs a predetermined control signal to the control device of the injection molding machine when it determines that the condition of the resin is not good. The determination device is a determination device in which the predetermined control signal is a signal that restricts the operation of the injection molding machine.

10. A determination device according to any one of claims 1 to 4, A determination device further comprising a display control unit that controls a display device to display information indicating the determination result of the determination unit on the display device.

11. A determination device according to any one of claims 1 to 4, A determination device that determines the quality of the measured resin for each injection molding machine by acquiring the load and multiple pieces of operation information from each of the multiple injection molding machines.

12. A determination device according to claim 11, The determination device is a determination device incorporated into a control device that manages a plurality of injection molding machines.

13. A method for determining the quality of the state of a resin measured in an injection molding machine, which comprises a cylinder and a screw for injecting the resin measured in the cylinder into a mold, A load acquisition step in which the load applied to the screw is acquired in accordance with the injection of the resin from the cylinder into the mold during multiple molding cycles, An operation information acquisition step in which operation information is acquired in a plurality of molding cycles, including at least one of the amount of movement of the screw, the amount of rotation, and the required time, from the time the screw starts the injection operation to inject the resin into the mold until the load exceeds a threshold, A statistical calculation step that calculates at least one statistical quantity among the amount of movement, the amount of rotation, and the required time based on the operation information obtained in the multiple molding cycles, A determination step to determine whether the measured resin is in good or bad condition based on the aforementioned statistical quantity, Includes, In the statistical calculation step, based on the acquired motion information, at least one of the variances of multiple movement amounts, multiple rotation amounts, and multiple required times is calculated. A determination method in which, if the calculated dispersion exceeds a second threshold, the determination step determines that the condition of the resin measured between multiple molding cycles is not good.

14. A method for determining whether the condition of a resin measured in an injection molding machine comprising a cylinder and a screw for injecting the resin measured in the cylinder into a mold, wherein A load acquisition step in which the load applied to the screw is acquired in accordance with the injection of the resin from the cylinder into the mold during multiple molding cycles, An operation information acquisition step in which operation information is acquired in a plurality of molding cycles, including at least one of the amount of movement of the screw, the amount of rotation, and the required time, from the time the screw starts the injection operation to inject the resin into the mold until the load exceeds a threshold, A statistical calculation step that calculates at least one statistical quantity among the amount of movement, the amount of rotation, and the required time based on the operation information obtained in the multiple molding cycles, A determination step to determine whether the measured resin is in good or bad condition based on the aforementioned statistical quantity, Includes, In the statistic calculation step, at least one of the following is calculated: representative values ​​of multiple displacement amounts, representative values ​​of multiple rotation amounts, and representative values ​​of multiple required times. The determination method further includes a range determination step of determining an acceptable range based on the calculated representative value, In the molding cycle after the tolerance range has been determined, the determination step determines whether the state of the measured resin is good or bad based on the operation information and the tolerance range. The injection molding machine includes a control device that controls the injection molding machine to measure the resin based on a metering condition value that includes at least one of the target temperature of the cylinder, the target rotational speed of the screw, and the target pressure of the resin. The determination method further includes a correction command step of outputting a correction signal for correcting the metering condition value based on the determination result of the determination step, The control device corrects the measurement condition value based on the correction signal, The correction signal is, If the amount of movement, the amount of rotation, or the required time is greater than the allowable range, the signal indicates that the measurement condition value should be corrected to be smaller than the current measurement condition value. A determination method comprising a signal indicating that if the amount of movement, the amount of rotation, or the required time is smaller than the allowable range, the measurement condition value should be increased from the current measurement condition value.

Images