Control device and control method

Abstract

An injection molding machine control device according to the present invention comprises: a temperature control unit that is a part of a heating cylinder part and controls the temperature of a second site adjacent to a first site including a hopper connection part to which a hopper is connected; and a physical quantity acquisition unit that acquires a physical quantity related to the consumption amount of a molding material injected from an injection cylinder. The temperature control unit lowers the temperature of the second site in accordance with the physical quantity.

Description

Control Device and Control Method

[0001] The present disclosure relates to a control device and a control method.

[0002] Japanese Patent Application Laid-Open No. 2014-61677 discloses a temperature control device for an injection molding machine. This temperature control device controls a heater attached to an injection cylinder to prevent the temperature of the molten resin from becoming lower than the set temperature.

[0003] These days, better control devices and control methods are desired.

[0004] A first aspect of the present disclosure is a control device for an injection molding machine including an injection cylinder having a hopper connection part to which a hopper is connected and a heating cylinder part that heats and melts a molding material introduced through the hopper connection part, the control device including: a temperature control part that controls the temperature of a second part adjacent to a first part that is part of the heating cylinder part and includes the hopper connection part; and a physical quantity acquisition part that acquires a physical quantity related to the consumption amount of the molding material ejected from the injection cylinder, wherein the temperature control part lowers the temperature according to the physical quantity acquired by the physical quantity acquisition part.

[0005] A second aspect of the present disclosure is a control method for an injection molding machine including an injection cylinder having a hopper connection part to which a hopper is connected and a heating cylinder part that heats and melts a molding material introduced through the hopper connection part, the control method including: a temperature control step of controlling the temperature of a second part adjacent to a first part that is part of the heating cylinder part and includes the hopper connection part; and a physical quantity acquisition step of acquiring a physical quantity related to the consumption amount of the molding material ejected from the injection cylinder, wherein in the temperature control step, the temperature is lowered according to the physical quantity acquired by the physical quantity acquisition step.

[0006] Figure 1 is a schematic diagram showing a part of an injection molding machine according to one embodiment. Figure 2 is a block diagram showing the configuration of a control device provided in the injection molding machine. Figure 3 is a graph showing the correspondence between the temperature correction amount and a physical quantity (volume flow rate). Figures 4A to 4C are graphs for explaining the content of the determination by the determination unit. Figure 5 is a flowchart of the control method according to one embodiment. Figure 6 is a graph schematically showing the temperature change of the molding material. Figure 7 is a graph showing the correspondence between the temperature correction amount and the ratio related to Modification Example 1. Figure 8 is a graph showing the correspondence between the temperature correction amount and the plasticization capacity utilization rate related to Modification Example 2. Figure 9 is a graph showing the correspondence between the temperature correction amount and the heat quantity related to Modification Example 3.

[0007] The injection cylinder of an injection molding machine has a hopper connection section where a cooling device (cooler) such as a water-cooled jacket is installed, and a heating cylinder section where a heating device (heater) such as a band heater is installed. Depending on the temperature difference between the hopper connection section and the heating cylinder section, heat from the heating cylinder section is transferred to the hopper connection section. In this case, the heater operates to compensate for the heat lost from the heating cylinder section. On the other hand, the cooler operates to prevent the area around the hopper connection section from becoming excessively hot. As a result, there was a problem in that the energy consumed by the heater and cooler increased excessively.

[0008] Based on the preliminary explanation above, one embodiment will be described below. In the following description, the term "program" (computer program, computer software) is also referred to as a "computer program product." A computer program product is not limited to programs stored on a storage medium, but also includes programs transmitted, distributed, or downloaded via networks such as the Internet.

[0009] (One Embodiment) Figure 1 is a schematic diagram showing a part of an injection molding machine 10 according to one embodiment. A part of the injection device 12 provided in the injection molding machine 10 is schematically shown in Figure 1.

[0010] The injection molding machine 10 is an industrial machine that produces molded products by injection molding. As shown in Figure 1, the injection molding machine 10 comprises an injection device 12 and a control device 14.

[0011] Although not shown in the diagram, the injection molding machine 10 further includes a mold clamping device (not shown). The mold clamping device is a machine that opens and closes a mold (not shown) and applies a clamping force to the mold when it is closed. The mold clamping device includes, for example, a plurality of platens (fixed platen, movable platen, etc.) that support the mold. The mold clamping device is, for example, a toggle-type mold clamping device, but is not limited to this. When the mold is closed, it forms a cavity according to the shape of the molded product.

[0012] The injection device 12 is a machine that injects and fills the cavity with molding material (such as resin), which is the material for the molded product. As shown in Figure 1, the injection device 12 comprises an injection cylinder 16, a screw 18, a cooler 20, and a heater 22.

[0013] The injection cylinder 16 has a hopper connection portion 24 and a heating cylinder portion 26. The hopper connection portion 24 is the part to which the hopper 28 is connected. The molding material is introduced into the hopper connection portion 24 via the hopper 28. The heating cylinder portion 26 is the part of the injection cylinder 16 that extends from the hopper connection portion 24 in the direction X1 towards the tip. The direction X1 towards the tip is along the axis LX of the injection cylinder 16 from the hopper connection portion 24 toward the injection nozzle 30 (described later). The molding material is introduced into the heating cylinder portion 26 via the hopper connection portion 24. The injection nozzle 30 is disposed at the tip portion 26t of the heating cylinder portion 26. The injection nozzle 30 can be connected to the tip portion 26t of the heating cylinder portion 26 via a nozzle adapter (not shown). The injection device 12 injects the molding material into the cavity via the injection nozzle 30.

[0014] In relation to the hopper connection portion 24 and the heating cylinder portion 26, the injection cylinder 16 has a first portion 32 and a second portion 34, which are described below. Each of the first portion 32 and the second portion 34 is a part of the injection cylinder 16. The first portion 32 is the portion that includes the hopper connection portion 24. In contrast, the second portion 34 is a part of the heating cylinder portion 26 that is adjacent to the hopper connection portion 24. The base end of the heating cylinder portion 26 may be identified as the second portion 34. The first portion 32 (hopper connection portion 24) is located below, for example, the hopper 28. The second portion 34 (heating cylinder portion 26) is located in the tip direction X1 relative to the first portion 32.

[0015] The screw 18 is disposed inside the injection cylinder 16. The screw 18 is rotatable about its central axis. The screw 18 is also movable along this central axis. This central axis may coincide with the axis LX of the injection cylinder 16. The injection device 12 is further equipped with multiple drive sources (motors, etc.) to realize the rotation and movement of the screw 18. The illustration of these multiple drive sources is omitted. The screw 18, together with the heating cylinder 26, forms a flow path FP from the hopper connection 24 to the screw head 18H (see Figure 1). The molding material introduced into the heating cylinder 26 is sent along this flow path FP to the tip 26t of the heating cylinder 26 and kneaded by the screw 18.

[0016] The cooler 20 is a cooling device disposed in the first part 32, which includes the hopper connection part 24. For example, the cooler 20 includes a water-cooled jacket. The cooler 20 cools the first part 32 to suppress the melting of the molding material. As a result, the cooler 20 suppresses the formation of bridges in the first part 32. In other words, the cooler 20 suppresses the adhesion of the molding material to the first part 32.

[0017] The heater 22 is a heating device disposed in the heating cylinder portion 26, which includes the second portion 34. The heater 22 melts the molding material supplied to the heating cylinder portion 26 by heating the heating cylinder portion 26. For example, the heater 22 may include a band heater. As shown in Figure 1, a plurality of heaters 22 (band heaters) may be arranged along the longitudinal side of the heating cylinder portion 26. In this case, the second portion 34 can be heated by the heater 22 that is closest to the first portion 32 among the plurality of heaters 22.

[0018] The heater 22 closest to the first part 32 among the multiple heaters 22 will be conveniently referred to as the proximity heater 22a in the following description.

[0019] Figure 2 is a block diagram showing the configuration of the control device 14 provided in the injection molding machine 10.

[0020] The control device 14 is an electronic device (computer) installed in the injection molding machine 10. For example, a numerical control device is included in the control device 14. The control device 14 has a display unit 36, an operation unit 38, a storage unit 40, and a calculation unit 42.

[0021] The display unit 36 ​​includes an output display device (display) (not shown). This output display device includes, for example, a display element. The display element forms, for example, a display screen (display panel). The display element is, for example, a liquid crystal element forming a liquid crystal panel, but is not limited to this.

[0022] The operation unit 38 includes an input device (not shown). This input device includes, for example, a keyboard, a pointing device, etc. The pointing device includes, for example, a mouse, a touch panel, etc. The touch panel may be arranged on the display screen of the display unit 36 ​​described above. The operation unit 38 (input device) may also include an operation panel.

[0023] The storage unit 40 includes one or more memory. The storage unit 40 includes non-volatile memory such as ROM (Read Only Memory), flash memory, or magnetic disk. Non-volatile memory is a storage medium that stores programs, tables, maps, etc., on a non-temporary basis. At least a portion of the storage unit 40 may be implemented by a portable storage medium such as USB (Universal Serial Bus) memory, memory card, or optical disk. The storage unit 40 may also include volatile memory such as RAM (Random Access Memory).

[0024] The arithmetic unit 42 includes a processing circuit capable of performing arithmetic processing. This processing circuit may have one or more processors. For example, the processing circuit may have a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), etc. The processing circuit may also have discrete devices.

[0025] The calculation unit 42 includes a physical quantity acquisition unit 44, a temperature control unit 46, an observation data acquisition unit 48, a determination unit 50, and a limit setting unit 52. The physical quantity acquisition unit 44, the temperature control unit 46, the observation data acquisition unit 48, the determination unit 50, and the limit setting unit 52 are realized by the processing circuit described above. For example, the physical quantity acquisition unit 44, the temperature control unit 46, the observation data acquisition unit 48, the determination unit 50, and the limit setting unit 52 are realized by a program stored in the storage unit 40 being executed by the processor of the calculation unit 42. The discrete devices described above may realize at least a part of the physical quantity acquisition unit 44, the temperature control unit 46, the observation data acquisition unit 48, the determination unit 50, and the limit setting unit 52.

[0026] The physical quantity acquisition unit 44 acquires a physical quantity relating to the amount of molding material consumed per predetermined number of shots injected from the injection cylinder 16. The predetermined number of shots is, for example, 1 (1 shot), but is not limited to this.

[0027] The physical quantity relating to the amount (consumption rate) of molding material injected from the injection cylinder 16 is, for example, the volumetric flow rate of the molding material per shot of the injection molding machine 10. This volumetric flow rate is the volume of molding material injected from the injection cylinder 16 per predetermined number of shots. This volume may correspond to the volume of molding material measured per predetermined number of shots. Therefore, the physical quantity acquisition unit 44 can derive the volumetric flow rate based, for example, on the following formula (1).

[0028]

[0029] Regarding this equation (1), VFR is the volumetric flow rate (cm³). ３The formula is ( / sec). Am is the amount of retraction of the screw 18 in the metering process (cm). This amount of retraction is the difference between the position of the screw 18 at the start of the metering process and the position of the screw 18 at the end of the metering process. D is the diameter of the screw 18 (cm). π is pi. T is the metering time (sec), which is the time required for the metering process, but it may also be the cycle time. Various numerical information included on the right side of formula (1) may be stored in advance by the memory unit 40. The amount of retraction (Am) and the metering time (T) may change depending on the type of molding material introduced into the injection cylinder 16. The operator may teach the physical quantity acquisition unit 44 these various numerical information using the operation unit 38.

[0030] The volumetric flow rate described above may be derived based on the volume of molding material injected from the injection cylinder 16 per unit time. Alternatively, the volumetric flow rate may be derived based on the volume of molding material being measured per unit time.

[0031] The temperature control unit 46 adjusts at least the second of the two part temperatures, which are the first part temperature and the second part temperature, based on the physical quantity acquired by the physical quantity acquisition unit 44. The first part temperature is the temperature of the first part 32 described above. More specifically, the first part temperature is the set temperature of the cooler 20 responsible for cooling the first part 32. In contrast, the second part temperature is the temperature of the second part 34 described above. More specifically, the second part temperature is the set temperature of one or more heaters 22 responsible for heating the second part 34. When the injection molding machine 10 is in operation, the second part temperature is usually higher than the first part temperature.

[0032] The temperature control unit 46 identifies, for example, a temperature correction amount corresponding to the volumetric flow rate, and adjusts at least the second of the first and second part temperatures based on that temperature correction amount. The temperature control unit 46 may also identify a temperature correction amount for adjusting the first part temperature and a temperature correction amount for adjusting the second part temperature. The temperature correction amounts are identified, for example, as described below.

[0033] Figure 3 is a graph showing the correspondence between the temperature correction amount and the physical quantity (volume flow rate), CR (CR1).

[0034] The correspondence CR1 between the temperature correction amount and the volumetric flow rate, shown in Figure 3, is determined in advance, for example, based on experiments, and is stored in the memory unit 40. This correspondence may be determined according to the type of molding material. In that case, the memory unit 40 can store multiple correspondences CR1 according to the type of molding material. The temperature control unit 46 determines the temperature correction amount corresponding to the physical quantity obtained by the physical quantity acquisition unit 44, based on this correspondence and the physical quantity obtained by the physical quantity acquisition unit 44. For example, if the physical quantity obtained by the physical quantity acquisition unit 44 is x, the temperature control unit 46 determines y as the temperature correction amount (see Figure 3). The type of molding material may be taught to the temperature control unit 46 by the operator using the operation unit 38, for example.

[0035] The temperature control unit 46 may lower the temperature of the second part as the physical quantity acquired by the physical quantity acquisition unit 44 decreases. In that case, the above-mentioned temperature correction amount (correspondence relationship) for the temperature of the second part may be determined such that the temperature of the second part decreases as the physical quantity acquired by the physical quantity acquisition unit 44 decreases.

[0036] The temperature control unit 46 may increase the temperature of the first part as the physical quantity acquired by the physical quantity acquisition unit 44 increases. In that case, the above-mentioned temperature correction amount (correspondence relationship) for the temperature of the first part may be determined such that the temperature of the first part increases as the physical quantity acquired by the physical quantity acquisition unit 44 increases.

[0037] The temperature control unit 46 may select whether or not to raise the temperature of the first part depending on the type of molding material. For example, if the molding material introduced into the hopper connection 24 is of a type that is less likely to form bridges inside the injection cylinder 16, the temperature control unit 46 may perform a process to raise the temperature of the first part.

[0038] The observation data acquisition unit 48 acquires predetermined observation data that can be observed during the operation of the injection molding machine 10 by various sensors provided in the injection molding machine 10. The predetermined observation data includes, but is not limited to, data indicating metering time, data indicating cycle time, data indicating torque changes of the screw 18 in the metering process, pressure of the screw 18 in the injection process, and in-mold pressure of the closed mold. The observation data acquisition unit 48 acquires predetermined observation data, for example, for each molding cycle.

[0039] The determination unit 50 determines whether the temperature control by the temperature control unit 46 is appropriate based on predetermined observation data acquired by the observation data acquisition unit 48. More specifically, the determination unit 50 determines, for example, whether the operating state of the injection molding machine 10 is abnormal (unstable, etc.) based on predetermined observation data. If the operating state of the injection molding machine 10 is abnormal, the determination unit 50 determines that the temperature control by the temperature control unit 46 is not appropriate.

[0040] Figures 4A to 4C are graphs that explain the content of the determination made by the determination unit 50.

[0041] The determination unit 50 determines whether the temperature control by the temperature control unit 46 is appropriate based on, for example, whether predetermined observation data falls within a predetermined monitoring range Rm. Each of the upper and lower limits of this monitoring range Rm (Rm1) can be determined relative to a reference value Vm determined in advance for the observation data (predetermined observation data) (FIG. 4A). The reference value Vm may be set based on predetermined observation data acquired before at least either the first part temperature or the second part temperature is changed, or may be set based on an experiment. The operator may use the operation unit 38 to teach the reference value Vm to the determination unit 50. Without determining the reference value Vm, the monitoring range Rm (Rm2) may be appropriately set (FIG. 4B). In that case, the operator may use the operation unit 38 to teach each of the upper and lower limits to the determination unit 50. The monitoring range Rm (Rm3) may be determined based on the transition (moving average) of predetermined observation data estimated in advance based on an experiment or the operation results of the injection molding machine 10 (FIG. 4C). When the predetermined observation data deviates from the monitoring range Rm, the determination unit 50 determines that the temperature control by the temperature control unit 46 is inappropriate.

[0042] When the determination unit 50 determines that the temperature control by the temperature control unit 46 is inappropriate, it feeds back the result of the determination to the temperature control unit 46. The temperature control unit 46 readjusts the second part temperature based on the feedback from the determination unit 50. The temperature control unit 46 may adjust (readjust) the first part temperature based on the feedback from the determination unit 50. In this case, the temperature control unit 46 readjusts at least either the first part temperature or the second part temperature based on the actual temperature n cycles before (n≥1) from the molding cycle in which it is determined that the temperature control is inappropriate. The actual temperature is the temperature measured by a temperature sensor appropriately provided in the injection device 12. The temperature control unit 46 may readjust at least either the first part temperature or the second part temperature based on the actual temperature t seconds before (t>0) from the time when it is determined by the determination unit 50 that the temperature control is inappropriate. In these cases, each of n and t described above is appropriately determined in advance.

[0043] The limit setting unit 52 sets at least one of the allowable range of the second part temperature and the adjustment limit according to the type of the molding material. The adjustment limit is the limit of the adjustment amount by the temperature control unit 46 of the second part temperature. In this case, the storage unit 40 stores in advance the type of the molding material, the allowable range, and the adjustment limit in association with each other. The limit setting unit 52 can automatically set the allowable range and the adjustment limit according to the type of the molding material. The limit setting unit 52 may change at least one of the allowable range and the adjustment limit according to an instruction from the operator. The operator can give an instruction to the limit setting unit 52 using the operation unit 38. The limit setting unit 52 may set at least one of the allowable range and the adjustment limit of the first part temperature.

[0044] FIG. 5 is a flowchart of a control method according to an embodiment.

[0045] The control device 14 can execute the control method shown in FIG. 5. For example, when an arithmetic unit 42 (processor) provided in the control device 14 which is a computer executes a program stored by a storage unit 40 (memory), the control method of FIG. 5 is realized. As shown in FIG. 5, the control method includes a limit setting step S1, a physical quantity acquisition step S2, a temperature control step S3, an observation data acquisition step S4, a determination step S5, and a readjustment step S6.

[0046] In the limit setting step S1, the limit setting unit 52 sets at least one of the allowable range of the second part temperature and the adjustment limit according to the type of the molding material. In the limit setting step S1, the limit setting unit 52 may automatically set at least one of the allowable range of the second part temperature and the adjustment limit. Although not shown, a step (limit change step) in which the limit setting unit 52 changes at least one of the allowable range and the adjustment limit according to an instruction from the operator may be appropriately executed as necessary. In the limit setting step S1, the limit setting unit 52 may set at least one of the allowable range and the adjustment limit of the first part temperature.

[0047] In the physical quantity acquisition step S2, the physical quantity acquisition unit 44 acquires the above-described physical quantity.

[0048] In the temperature control step S3, the temperature control unit 46 performs the temperature control described above based on the physical quantity acquired in the physical quantity acquisition step S2. Based on the allowable range, adjustment limit, etc. set in the limit setting step S1, the temperature control unit 46 performs the temperature control.

[0049] In observation data acquisition step S4, the observation data acquisition unit 48 acquires predetermined observation data.

[0050] In the determination step S5, the determination unit 50 determines whether the temperature control in the temperature control step S3 was appropriate, based on the predetermined observation data acquired in the observation data acquisition step S4.

[0051] If it is determined in the determination step S5 that the temperature control is inappropriate, the readjustment step S6 is started. In the readjustment step S6, the temperature control unit 46 readjusts at least one of the first part temperature and the second part temperature based on the result of the determination in the determination step S5. In this case, the temperature control unit 46 may readjust at least one of the first part temperature and the second part temperature based on the actual temperature n cycles or t seconds ago as described above.

[0052] The control device 14 and control method according to this embodiment can suppress the energy consumption of the heater 22 and the cooler 20, respectively. This will be explained below with reference to Figure 6.

[0053] Figure 6 is a schematic graph showing the temperature changes of the molding material.

[0054] Figure 6 shows the temperature progression from the time the molding material is introduced into the heating cylinder 26 until the molding material reaches the tip 26t of the heating cylinder 26. Each of the multiple arrows shown in Figure 6 indicates the temperature progression during one molding cycle. The multiple arrows shown with dotted lines correspond to a first example (EX1) of multiple molding cycles performed consecutively. The multiple arrows shown with thick lines correspond to a second example (EX2) of multiple molding cycles performed consecutively.

[0055] As the molding cycle is repeated, the molding material supplied to the heating cylinder 26 gradually moves towards the tip X1. The smaller the amount of molding material consumed per shot injected from the injection cylinder 16, the smaller the amount of molding material moved towards the tip X1 per molding cycle. Therefore, the smaller the amount of molding material consumed per shot injected from the injection cylinder 16, the longer the time it takes for the molding material supplied to the heating cylinder 26 to reach the tip 26t of the heating cylinder 26. If the time it takes for the molding material supplied to the heating cylinder 26 to reach the tip 26t of the heating cylinder 26 is longer, the time the molding material is heated by the heater 22 is also longer. If the time the molding material is heated by the heater 22 is longer, even if the set temperature of the heater 22 is lowered somewhat, the molding material can be sufficiently heated and melted before it reaches the tip 26t. In other words, if the molding material is heated by the heater 22 for a long time, even if the set temperature of the heater 22 is lowered somewhat, the temperature of the molding material can reach the target heating temperature Kt before it reaches the tip 26t. For this reason, there may be room to lower the set temperature of the heater 22 depending on the amount of molding material consumed per shot injected from the injection cylinder 16.

[0056] For example, in the first example EX1 and the second example EX2 shown in Figure 6, five molding cycles are performed from the time the molding material is introduced into the heating cylinder 26 until it is injected. In the first example EX1, the temperature of the molding material reaches the target heating temperature Kt after the completion of the second molding cycle. In this case, as shown in the second example EX2, even if the set temperature of the heater 22 is lowered to some extent (temperature Kd), the molding material will be heated in time for the fifth molding cycle in which it is injected. In other words, in the case of the first example EX, there is room to lower the set temperature of the heater 22 by temperature Kd.

[0057] Based on this, according to this embodiment, the control device 14 includes a temperature control unit 46. The temperature control unit 46 lowers the second part temperature according to a physical quantity related to the amount of molding material consumed per predetermined number of shots (volume flow rate) injected from the injection cylinder 16. For example, the temperature control unit 46 lowers the second part temperature as the physical quantity acquired by the physical quantity acquisition unit 44 increases.

[0058] This suppresses energy consumption by the heater 22 within the range where the molding material can be sufficiently heated and melted. Furthermore, by lowering the set temperature of the heater 22, the temperature difference between the first part temperature and the second part temperature is reduced. This reduction in temperature difference suppresses heat transfer from the second part 34 to the first part 32. As a result, the cooling efficiency of the first part 32 by the cooler 20 can be improved, and energy consumption by the cooler 20 can also be reduced. Therefore, according to this embodiment, energy consumption by both the heater 22 and the cooler 20 can be reduced.

[0059] Furthermore, the greater the amount of movement of the molding material in the leading edge direction X1 per molding cycle, the less likely the molding material is to accumulate in the hopper connection section 24. Considering this, it can be said that the greater the amount of movement, the less likely the molding material is to stick to the hopper connection section 24. Therefore, the greater the amount of movement, the more room there may be to raise the set temperature of the cooler 20.

[0060] In this respect, according to this embodiment, the temperature control unit 46 may raise the temperature of the first part as the physical quantity acquired by the physical quantity acquisition unit 44 increases. By raising the temperature of the first part, energy consumption by the cooler 20 is suppressed. Also, in this case, the temperature difference between the temperature of the first part and the temperature of the second part is reduced, so heat transfer from the second part 34 to the first part 32 is suppressed. As a result, energy consumption of both the heater 22 and the cooler 20 can be suppressed.

[0061] The temperature control unit 46 may select (decide) whether or not to raise the temperature of the first part depending on the type of molding material. For example, if a type of molding material that is relatively less likely to cause bridging is introduced into the hopper connection unit 24, the temperature control unit 46 may perform a process to raise the temperature of the first part according to a physical quantity (volume flow rate). In this way, the temperature control unit 46 can effectively suppress the occurrence of bridging in the first part 32.

[0062] The control device 14 further includes a determination unit 50. The determination unit 50 can determine whether the temperature control by the temperature control unit 46 is appropriate based on predetermined observation data.

[0063] If the determination unit 50 determines that the temperature control performed by the temperature control unit 46 is inappropriate, it feeds back the result of its determination to the temperature control unit 46. This allows the temperature control unit 46 to readjust the temperatures of the first and second parts in response to the feedback from the determination unit 50. In other words, the determination unit 50 can prompt the temperature control unit 46 to perform appropriate temperature control.

[0064] The control device 14 further includes a limit setting unit 52. The limit setting unit 52 can set at least one of the allowable range and adjustment limit of the second part temperature depending on the type of molding material. The limit setting unit 52 may also set at least one of the allowable range and adjustment limit of the first part temperature depending on the type of molding material. This allows for appropriate temperature control depending on the type of molding material.

[0065] The limit setting unit 52 changes at least one of the allowable range and the adjustment limit in accordance with the operator's instructions. This is done for the convenience of the operator.

[0066] As described above, a plurality of heaters 22 may be arranged along the longitudinal side of the heating cylinder 26. In this case, the proximity heater 22a may be responsible for heating the second part 34. The temperature control by the temperature control unit 46 includes a process to lower the set temperature of the proximity heater 22a. By lowering the set temperature of the proximity heater 22a, heat transfer from the second part 34 to the first part 32 can be suppressed. Note that two or more heaters 22, including the proximity heater 22a, may be responsible for heating the second part 34.

[0067] One embodiment may be modified as follows. In the following modifications, explanations that overlap with the embodiment will be omitted as appropriate. Also, components identical to those described in the embodiment will be denoted by the same reference numerals.

[0068] (Modification 1) The temperature control unit 46 may perform temperature control based on the ratio of the volume of the flow path FP formed in the injection cylinder 16 to the volumetric flow rate of the molding material per shot of the injection molding machine 10. This ratio is, for example, the volume of the flow path FP formed in the injection cylinder 16 divided by the volumetric flow rate of the molding material per shot of the injection molding machine 10.

[0069] Figure 7 is a graph showing the correspondence CR (CR2) between the temperature correction amount and the ratio related to Modification Example 1.

[0070] The temperature control unit 46 may identify a temperature correction amount corresponding to the above-mentioned ratio and adjust the second part temperature based on that temperature correction amount. The correspondence relationship CR2 between the temperature correction amount and the ratio shown in Figure 7 is determined in advance, for example, based on experiments, similar to the correspondence relationship CR1 between the temperature correction amount and the volumetric flow rate (see one embodiment). As a result, the temperature control unit 46 can identify a temperature correction amount (y in Figure 7) corresponding to the above-mentioned ratio (for example, x in Figure 7) based on the correspondence relationship CR2. The temperature control unit 46 may adjust the first part temperature based on the temperature correction amount corresponding to the above-mentioned ratio.

[0071] (Modification 2) The temperature control unit 46 may perform temperature control based on the plasticizing capacity utilization rate. The plasticizing capacity utilization rate is the ratio of the weight of the molded product formed by the injection molding machine 10 to the plasticizing capacity of the screw 18. More specifically, the plasticizing capacity utilization rate is the ratio obtained by dividing the weight of the molded product by the plasticizing capacity. The plasticizing capacity of the screw 18 is the weight of the molding material melted per unit time (molten weight) by the injection cylinder 16.

[0072] The weight of the molded product may be derived based on the volumetric flow rate of the molding material forming the molded product in the heating cylinder 26 and the melt density of the molding material. That is, the weight of the molded product can be derived based on the product of the melt density of the molding material forming the molded product and the volumetric flow rate obtained by the above formula (1).

[0073] Figure 8 is a graph showing the correspondence CR (CR3) between the temperature correction amount and the plasticizing capacity utilization rate related to Modification Example 2.

[0074] The temperature control unit 46 may specify a temperature correction amount corresponding to the plasticizing capacity utilization rate and adjust the second part temperature based on that temperature correction amount. The correspondence relationship CR3 between the temperature correction amount and the plasticizing capacity utilization rate shown in Figure 8 is determined in advance, for example, based on experiments, similar to the correspondence relationship CR1 between the temperature correction amount and the volumetric flow rate (see one embodiment). As a result, the temperature control unit 46 can specify a temperature correction amount (y in Figure 8) corresponding to the plasticizing capacity utilization rate (for example, x in Figure 8) based on the correspondence relationship CR3. The temperature control unit 46 may adjust the first part temperature based on the temperature correction amount corresponding to the plasticizing capacity utilization rate.

[0075] (Modification 3) The physical quantity acquisition unit 44 may acquire a physical quantity relating to the amount of heat supplied to the molding material in order to melt it, as a physical quantity relating to the amount of molding material consumed by the injection cylinder 16. The above-mentioned amount of heat can be derived, for example, based on the following formula (2).

[0076]

[0077] In this equation (2), EM is the amount of heat. ρ is the melt density of the molding material. π, D, and Am are the same as in one embodiment. c is the specific heat of the molding material. K ｏ This is the temperature of the molding material in the injection nozzle 30. This temperature can be replaced by the temperature of the injection nozzle 30 detected by a temperature sensor appropriately provided in the injection device 12. ｉ This is the temperature of the molding material at the hopper connection section 24. This temperature can be replaced with an estimated temperature of the molding material at the hopper connection section 24. This estimated temperature can be derived based on the set temperature (drying temperature) of the drying device that pre-dries the molding material introduced into the hopper connection section 24. Regarding the volumetric flow rate, a part of the right-hand side of equation (2) can be obtained by multiplying both sides of equation (1), which was described in one embodiment, by the metering time. Based on this, the physical quantity acquisition unit 44 may use the volumetric flow rate of the molding material per shot of the injection molding machine 10 in the process of deriving the above-mentioned heat quantity.

[0078] Figure 9 is a graph showing the correspondence CR (CR4) between the temperature correction amount and the heat quantity related to Modification Example 3.

[0079] The temperature control unit 46 may identify a temperature correction amount corresponding to the heat quantity and adjust the second part temperature based on that temperature correction amount. The correspondence relationship CR4 between the temperature correction amount and the heat quantity shown in Figure 9 is determined in advance, for example, based on experiments, similar to the correspondence relationship between the temperature correction amount and the volumetric flow rate (see one embodiment). As a result, the temperature control unit 46 can identify a temperature correction amount (y in Figure 9) corresponding to the heat quantity (for example, x in Figure 9) based on the correspondence relationship CR4. The temperature control unit 46 may adjust the first part temperature based on the temperature correction amount corresponding to the heat quantity as described above.

[0080] (Modification 4) The determination unit 50 may determine whether the temperature control by the temperature control unit 46 is appropriate based on the monitoring results from a monitoring device (alarm management device) that monitors the operating status of the injection molding machine 10. The function of the monitoring device (monitoring unit) may be provided in the control device 14.

[0081] Furthermore, the determination unit 50 may determine whether the temperature control by the temperature control unit 46 is appropriate based on the quality determination result from the quality determination device that determines the quality of the molded product. In that case, the determination unit 50 may determine that the temperature control by the temperature control unit 46 is inappropriate if the molded product is defective. The function of the quality determination device (quality determination unit) may be provided in the control device 14.

[0082] (Combinations of multiple variations) The above-mentioned variations may be combined as appropriate, within the bounds of consistency.

[0083] According to the above-described embodiment and its modifications, the control device 14 and control method can suppress the energy consumption of the heater 22 and the cooler 20, respectively.

[0084] With respect to the above-described embodiment, the following additional information is disclosed.

[0085] (Note 1) The control device (14) according to the present disclosure is a control device for an injection molding machine (10) equipped with an injection cylinder (16) having a hopper connection part (24) to which a hopper (28) is connected, and a heating cylinder part (26) for heating and melting the molding material introduced through the hopper connection part, and comprises a temperature control unit (46) that controls the temperature of a second part (34) which is part of the heating cylinder part and adjacent to a first part (32) including the hopper connection part, and a physical quantity acquisition unit (44) that acquires a physical quantity relating to the amount of molding material injected from the injection cylinder, wherein the temperature control unit lowers the temperature according to the physical quantity acquired by the physical quantity acquisition unit.

[0086] (Note 2) The control device described in Note 1 may be a control device in which the physical quantity is a physical quantity relating to the volumetric flow rate of the molding material.

[0087] (Note 3) The control device described in Note 2 may be a control device in which the physical quantity is the injection volume per predetermined number of shots of the molding material, the injection volume per unit time of the molding material, the measured volume of the molding material per predetermined number of shots, or the measured volume of the molding material per unit time.

[0088] (Note 4) The control device described in Note 2 or 3, wherein the temperature control unit is a control device that performs the temperature control based on the ratio of the volume of the flow path (FP) formed in the injection cylinder to the physical quantity.

[0089] (Note 5) The control device described in any one of Notes 1 to 3 may be a control device in which the temperature control unit performs the temperature control based on the ratio of the weight of the molded product formed by the injection molding machine to the plasticizing capacity of the injection molding machine, and the plasticizing capacity is the molten weight per unit time of the molding material melted by the injection cylinder.

[0090] (Note 6) The control device described in any one of Notes 1 to 3 may be a control device in which the physical quantity is a physical quantity relating to the amount of heat supplied to the molding material in order to melt the molding material.

[0091] (Note 7) A control device as described in any one of Notes 1 to 6 may further include a determination unit (50) that determines whether the temperature control is appropriate based on predetermined observation data observed from the injection molding machine.

[0092] (Note 8) The control device described in Note 7 may also be a control device in which, if the determination unit determines that the temperature control is inappropriate, it feeds back the result of the determination by the determination unit to the temperature control unit.

[0093] (Note 9) The control device described in any one of Notes 1 to 8 may further include a limit setting unit (52) that can set at least one of the following according to the type of molding material: the permissible range of the temperature of the second part and the adjustment limit, which is the limit of the amount of temperature adjustment of the second part in the temperature control.

[0094] (Note 10) The control device described in Note 9 may be a control device in which the limit setting unit can change at least one of the allowable range and the adjustment limit according to the operator's instructions.

[0095] (Note 11) The control device described in any one of Notes 1 to 10 may be a control device in which the injection molding machine is provided with a plurality of heaters (22) arranged along the longitudinal side of the heating cylinder, and the temperature control includes a process to lower the set temperature of the heater that is closest to the first part among the plurality of heaters.

[0096] (Note 12) The control device described in Note 11 may be a control device in which the second part temperature, which is the temperature of the second part, is set higher than the first part temperature, which is the temperature of the first part, and the temperature control unit sets the second part temperature lower as the physical quantity acquired by the physical quantity acquisition unit becomes smaller.

[0097] (Note 13) The control device described in any one of Notes 1 to 12, wherein the temperature control unit raises the temperature of the first part according to the physical quantity acquired by the physical quantity acquisition unit.

[0098] (Note 14) The control method according to the present disclosure is a control method for an injection molding machine (10) equipped with an injection cylinder (16) having a hopper connection part (24) to which a hopper (28) is connected, and a heating cylinder part (26) for heating and melting the molding material introduced through the hopper connection part, comprising: a temperature control step (S3) for controlling the temperature of a second part (34) which is part of the heating cylinder part and adjacent to a first part (32) including the hopper connection part, and a physical quantity acquisition step (S2) for acquiring a physical quantity relating to the amount of molding material injected from the injection cylinder, wherein the temperature control step lowers the temperature according to the physical quantity acquired by the physical quantity acquisition step.

[0099] While this disclosure has been described in detail, it is not limited to the individual embodiments described above. These embodiments can be added, replaced, modified, partially deleted, etc., in any way that does not depart from the gist of this disclosure or from the spirit of this disclosure derived from the claims and their equivalents. These embodiments can also be implemented in combination. For example, the order of operations and processes in the embodiments described above are given as examples only and are not limited thereto. The same applies when numerical values ​​or mathematical formulas are used in the description of the embodiments described above.

[0100] 10...Injection molding machine 14...Control device 16...Injection cylinder 22...Heater 24...Hopper connection part 26...Heating cylinder part 28...Hopper 32...First part 34...Second part 38...Operation part 44...Physical quantity acquisition part 46...Temperature control part 50...Determination part 52...Limit setting part FP...Flow path

Claims

1. A control device for an injection molding machine, comprising an injection cylinder having a hopper connection section to which a hopper is connected, and a heating cylinder section for heating and melting a molding material introduced through the hopper connection section, the control device comprising: a temperature control section which is part of the heating cylinder section and is adjacent to a first section including the hopper connection section for temperature control of a second section; and a physical quantity acquisition section which acquires a physical quantity relating to the amount of molding material injected from the injection cylinder, wherein the temperature control section lowers the temperature according to the physical quantity acquired by the physical quantity acquisition section.

2. A control device according to claim 1, wherein the physical quantity is a physical quantity relating to the volumetric flow rate of the molding material.

3. A control device according to claim 2, wherein the physical quantity is the injection volume per predetermined number of shots of the molding material, the injection volume per unit time of the molding material, the measured volume of the molding material per predetermined number of shots, or the measured volume of the molding material per unit time.

4. A control device according to claim 2 or 3, wherein the temperature control unit performs the temperature control based on the ratio of the volume of the flow path formed in the injection cylinder to the physical quantity.

5. A control device according to any one of claims 1 to 3, wherein the temperature control unit performs the temperature control based on the ratio of the weight of the molded product formed by the injection molding machine to the plasticizing capacity of the injection molding machine, and the plasticizing capacity is the molten weight per unit time of the molding material melted by the injection cylinder.

6. A control device according to any one of claims 1 to 3, wherein the physical quantity is a physical quantity relating to the amount of heat supplied to the molding material in order to melt the molding material.

7. A control device according to any one of claims 1 to 6, further comprising a determination unit that determines whether the temperature control is appropriate based on predetermined observation data observed from the injection molding machine.

8. A control device according to claim 7, wherein if the determination unit determines that the temperature control is inappropriate, the determination unit feeds back the result of the determination to the temperature control unit.

9. A control device according to any one of claims 1 to 8, further comprising a limit setting unit capable of setting at least one of the following according to the type of molding material: an allowable range of the temperature of the second part and an adjustment limit which is the limit of the amount of temperature adjustment of the second part in the temperature control.

10. A control device according to claim 9, wherein the limit setting unit is capable of changing at least one of the allowable range and the adjustment limit in accordance with the operator's instructions.

11. A control device according to any one of claims 1 to 10, wherein the injection molding machine is provided with a plurality of heaters arranged along the longitudinal side of the heating cylinder, and the temperature control includes a process of lowering the set temperature of the heater among the plurality of heaters that is closest to the first portion.

12. A control device according to claim 11, wherein the second part temperature, which is the temperature of the second part, is set higher than the first part temperature, which is the temperature of the first part, and the temperature control unit sets the second part temperature lower as the physical quantity acquired by the physical quantity acquisition unit becomes smaller.

13. A control device according to any one of claims 1 to 12, wherein the temperature control unit raises the temperature of the first part according to the physical quantity obtained by the physical quantity acquisition unit.

14. A control method for an injection molding machine comprising an injection cylinder having a hopper connection portion to which a hopper is connected, and a heating cylinder portion for heating and melting a molding material introduced through the hopper connection portion, the control method comprising: a temperature control step for controlling the temperature of a second portion which is part of the heating cylinder portion and adjacent to a first portion including the hopper connection portion; and a physical quantity acquisition step for acquiring a physical quantity relating to the amount of molding material injected from the injection cylinder, wherein the temperature control step lowers the temperature according to the physical quantity acquired by the physical quantity acquisition step.

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