Injection molding machine

Abstract

To provide an injection molding machine that can appropriately set a frequency of supplying a lubricant without installing a new temperature sensor.SOLUTION: An injection molding machine performs: an injection process in which plasticized molding material is injected into a cavity by moving a screw back and forth; a lubrication process in which, when the number of times the injection process has been performed reaches a threshold number, a lubrication pump is driven to supply lubricant to an object to be lubricated; and a threshold update process in which the threshold number of times is updated. In the threshold update process, when a power of the injection molding machine is turned on, the injection molding machine determines whether a non-powered period during which no power is applied to a heater is equal to or longer than a threshold period, and if the non-powered period is equal to or longer than the threshold period, updates the threshold number of times according to the temperature detected by the temperature sensor, and if the non-powered period is shorter than the threshold period, does not update the threshold number of times.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an injection molding machine that injects a molding material into a mold to produce an injection-molded product. [Background technology]

[0002] Conventionally, there has been known an injection molding machine that drives a lubrication pump to supply grease to objects to be lubricated (e.g., ball screws, toggle link mechanisms, bearings, slide sliding parts) when the number of times an injection process injects molten resin into a cavity of a clamped mold reaches a threshold value (e.g., 1,000 shots) (see, for example, Patent Document 1).

[0003] Here, the higher the temperature around the injection molding machine, the more the deterioration of the grease is accelerated. Therefore, Patent Document 2 discloses a technology for changing the greasing interval according to the temperature of the ball screw in order to supply grease to the object to be lubricated at appropriate intervals. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-024286 A [Patent Document 2] Japanese Patent Application Publication No. 11-268093 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the method of Patent Document 2 cannot appropriately determine the deterioration of grease in objects to be lubricated other than the ball screw. On the other hand, providing a temperature sensor for each of a plurality of objects to be lubricated causes a new problem of increasing the number of parts in the injection molding machine.

[0006] Furthermore, when Patent Document 2 was published in 1999, the temperature control of the factory where the injection molding machine was installed was not sufficient, so the temperature of the ball screw was constantly monitored. However, now that factory temperatures are well controlled, the only time the temperature around the injection molding machine changes significantly is when an injection molding machine is newly installed or relocated to the factory. Therefore, not only is constant temperature monitoring like that in Patent Document 2 unnecessary, but momentary temperature changes can cause the greasing interval to become unstable.

[0007] The present invention has been made to solve such problems in the conventional technology, and its purpose is to provide an injection molding machine that can appropriately set the frequency of lubricant supply without installing a new temperature sensor. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the present invention provides an injection molding machine comprising an injection device for injecting molding material into a cavity of a clamped mold and a control device for controlling the injection device, the injection device comprising a heating cylinder filled with molding material, a heater for heating the heating cylinder, and a screw for plasticizing the molding material by moving backward inside the heating cylinder and for injecting the plasticized molding material into the cavity by moving forward inside the heating cylinder, the injection device further comprising a temperature sensor for detecting the temperature of the heating cylinder, and a grease pump for supplying lubricant to an object to be lubricated, and the control device controls the injection device to move forward and backward to variably inject the molding material into the cavity. The control device executes an injection process for injecting plasticized molding material into the cavity, a lubrication process for driving the lubrication pump to supply lubricant to the lubrication target when the number of times the injection process has been executed reaches a threshold number, and a threshold update process for updating the threshold number, wherein in the threshold update process, when the power to the injection molding machine is turned on, the control device determines whether a non-energizing period during which no current is applied to the heater is equal to or longer than a threshold period, and if the non-energizing period is equal to or longer than the threshold period, updates the threshold number in accordance with the temperature detected by the temperature sensor, and if the non-energizing period is shorter than the threshold period, does not update the threshold number. Effect of the Invention

[0009] According to the present invention, it is possible to obtain an injection molding machine that can appropriately set the frequency of supplying a lubricant without providing a new temperature sensor. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a side view of an injection molding machine according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a hardware configuration diagram of an injection molding machine. [Diagram 3] 4 is a flowchart of an injection control process. [Figure 4] 13 is a flowchart of a threshold update process. [Diagram 5] 13 is a flowchart showing a modified example (A) of the process of step S25 and a modified example of the process of step S15. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] An injection molding machine 10 according to the present invention will be described below with reference to the drawings. The injection molding machine 10 is a device that injects a measured amount of molding material into a mold to form an injection-molded product (hereinafter referred to as "injection molding").

[0012] [Configuration of injection molding machine 10] Fig. 1 is a side view of an injection molding machine 10 according to this embodiment. Fig. 2 is a hardware configuration diagram of the injection molding machine 10. As shown in Figs. 1 and 2, the injection molding machine 10 mainly includes a mold clamping device 20, an injection device 30, and a control device 60.

[0013] The clamping device 20 opens, closes, and clamps the mold 21. Specifically, the clamping device 20 mainly includes a fixed die plate 23 that supports a fixed-side mold 22, and a movable die plate 25 that supports a movable-side mold 24. The fixed-side mold 22 and the movable-side mold 24 are supported so as to face each other in the left-right direction (horizontal direction) of the injection molding machine 10.

[0014] The movable die plate 25 moves left and right along the tie bars 27 by transmitting the driving force of the die opening / closing motor 28 through the toggle link mechanism 26. When the movable die plate 25 moves leftward, the fixed die 22 and the movable die 24 move away from each other. On the other hand, when the movable die plate 25 moves rightward, the fixed die 22 and the movable die 24 come into contact with each other, forming a cavity (internal space) inside the die 21. Then, when pressure is further applied in a direction to move the movable die plate 25 rightward, the fixed die 22 and the movable die 24 are clamped.

[0015] The injection device 30 plasticizes, measures, and injects the molding material. The injection device 30 according to this embodiment is disposed apart from the mold clamping device 20 in the horizontal direction (to the right of the mold clamping device 20). The injection device 30 mainly includes a heating cylinder 31, a screw 32, a hopper 33, and a hopper block 34.

[0016] The heating cylinder 31 is a cylindrical member extending in the left-right direction of the injection molding machine 10. The heating cylinder 31 mainly includes a resin passage 35 and a nozzle 36. In addition, a band heater 39 for heating the heating cylinder 31 is attached to the outer circumferential surface of the heating cylinder 31.

[0017] The band heater 39 includes a cover that covers the heating cylinder 31 and a heating wire built into the cover. The band heater 39 can heat the heating cylinder 31 at different set temperatures in each region (e.g., the tip region, the middle region, and the base region) in the extension direction of the heating cylinder 31. However, the number of regions in the extension direction of the heating cylinder 31 that can have individual temperatures set is not limited to three.

[0018] The band heater 39 heats each area of ​​the heating cylinder 31 to the set temperature set through the display input device 67 by being supplied with a current corresponding to the set temperature from the control device 60 (hereinafter referred to as the "energized state"). On the other hand, the band heater 39 stops heating the heating cylinder 31 by stopping the supply of current from the control device 60 (hereinafter referred to as the "non-energized state"). When the band heater 39 is in the non-energized state, the temperature of the heating cylinder 31 naturally drops over time and eventually reaches the ambient temperature around the injection molding machine 10.

[0019] The resin passage 35 is a cylindrical space extending in the axial direction (longitudinal direction) inside the heating cylinder 31. The resin passage 35 communicates with the outside of the heating cylinder 31 (the cavity of the mold 21) through a nozzle 36 provided at the tip (front end) of the heating cylinder 31. In other words, the resin passage 35 is a space extending from the nozzle 36 along the axial direction.

[0020] The screw 32 is a cylindrical member. A spiral groove is formed on the outer circumferential surface of the screw 32. The screw 32 is accommodated in the internal space of the heating cylinder 31 in a state in which the screw 32 can move in the left-right direction of the injection molding machine 10 (hereinafter, referred to as "advance and retreat") and can rotate. The screw 32 advances and retreats when a driving force of an injection motor 37 is transmitted thereto, and rotates when a driving force of a metering motor 38 is transmitted thereto.

[0021] More specifically, when the injection motor 37 is rotated in the forward direction, the screw 32 moves (forward) toward the tip of the heating cylinder 31 (i.e., the nozzle 36). On the other hand, when the injection motor 37 is rotated in the reverse direction, the screw 32 moves (rearward) toward the base end of the heating cylinder 31 (i.e., the side opposite the nozzle 36). Hereinafter, within the range that the tip position of the screw 32 can reach within the heating cylinder 31, the position closest to the nozzle 36 is referred to as the "forward limit," and the position farthest from the nozzle 36 is referred to as the "rear limit." In addition, the terms "forward rotation" and "reverse rotation" of the injection motor 37 do not specify an absolute direction of rotation, but merely specify a relative relationship (i.e., forward rotation and reverse rotation are rotations in opposite directions).

[0022] The hopper 33 is a funnel-shaped member that stores the raw molding material. The hopper block 34 is a member that supports the heating cylinder 31 and the hopper 33. The hopper 33 communicates with a resin passage 35 through the hopper block 34 at a portion of the heating cylinder 31 closer to the base end than the tip end. The molding material stored in the hopper 33 is supplied to the resin passage 35 of the heating cylinder 31 through an opening provided at the lower end. The molding material used in this injection molding machine 10 is, for example, so-called "pellets" that are formed into a cylindrical shape.

[0023] [Configuration of control device 60] 2, the control device 60 includes a central processing unit (CPU) 61, which is a calculation means, and a memory 62. The memory 62 is, for example, a read only memory (ROM), a random access memory (RAM), a hard disk drive (HDD), or a combination of these. The control device 60 realizes processing, which will be described later, by the CPU 61 reading and executing program codes stored in the memory 62. The memory 62 is also used as a work area when the CPU 61 executes a program.

[0024] However, the specific configuration of the control device 60 is not limited to this, and may be realized by hardware such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA).

[0025] The control device 60 controls the overall operation of the injection molding machine 10. More specifically, the control device 60 controls the mold opening / closing motor 28, the injection motor 37, the metering motor 38, the band heater 39 (heater), and the oil supply pump 40 based on various signals output from a rotary encoder 64, a load cell 65 (pressure sensor), a plurality of temperature sensors 66a, 66b, 66c, and a display input device 67.

[0026] The rotary encoder 64 is a sensor that detects the speed and tip position of the screw 32. More specifically, the rotary encoder 64 outputs a pulse signal corresponding to the rotation of the injection motor 37 to the control device 60. Then, the control device 60 specifies the speed of the screw 32 based on the number of pulse signals output per unit time. The control device 60 also specifies the tip position of the screw 32 based on the accumulated value of the pulse signals.

[0027] The load cell 65 is a sensor that detects the pressure applied to the screw 32. More specifically, the load cell 65 outputs a pressure signal (voltage value) corresponding to the pressure applied to the screw 32 to the control device 60. Then, the control device 60 identifies the pressure applied to the screw 32 based on the pressure signal output from the load cell 65.

[0028] The temperature sensors 66a, 66b, 66c detect the temperature of each region (e.g., the tip region, the middle region, and the base region) of the heating cylinder 31, and output a temperature signal indicating the detected temperature to the control device 60. That is, the injection molding machine 10 is provided with the temperature sensors 66a to 66c in a number corresponding to the regions of the heating cylinder 31 whose temperatures can be set individually.

[0029] Among the multiple temperature sensors 66a to 66c according to this embodiment, the temperature sensor 66a that detects the temperature of the tip region (more specifically, the nozzle 36) is not covered by the cover of the band heater 39. On the other hand, the temperature sensors 66b and 66c that detect the temperatures of the central region and the base end region are covered by the cover of the band heater 39. Therefore, when the band heater 39 is in a non-energized state, the temperature sensor 66a can more easily detect the temperature (ambient temperature) around the injection molding machine 10 than the temperature sensors 66b and 66c.

[0030] The grease supply pump 40 supplies grease (one example of a lubricant) stored in a grease tank (not shown) to each of a plurality of objects to be lubricated under the control of the control device 60. The objects to be lubricated according to this embodiment are, for example, the ball screw and toggle link mechanism 26 that slide the movable die plate 25, bearings installed in each part, and other sliding parts. The grease supply pump 40 and the objects to be lubricated are the same as those in the known injection molding machine 10, and therefore detailed description thereof will be omitted.

[0031] Furthermore, a display input device 67 is connected to the control device 60. The display input device 67 is a user interface that includes a display (display device) that displays various information to be notified to the operator, and buttons, switches, dials, and the like (input devices) that accept input operations by the operator. The display input device 67 may also include a touch panel superimposed on the display. The display input device 67 accepts input operations by the operator, and outputs an input signal corresponding to the accepted input operation to the control device 60.

[0032] The control device 60 receives power from an external power source and operates each section of the injection molding machine 10. The control device 60 is configured to be switchable, by an operator operating a power switch (not shown), between a "power ON state" in which the injection molding machine 10 receives power from the external power source, and a "power OFF state" in which the injection molding machine 10 cuts off the power supply from the external power source.

[0033] When the injection molding machine 10 is in a power-on state, each part of the injection molding machine 10 including the band heater 39 is operable. When a current is supplied to the band heater 39 in this state, the heating cylinder 31 rises to a set temperature. Note that the band heater 39 may be configured to be switchable between a powered state and a non-powered state when the injection molding machine 10 is in a power-on state.

[0034] On the other hand, when the power of the injection molding machine 10 is OFF, each part of the injection molding machine 10 including the band heater 39 becomes inoperable. Therefore, the heat generation of the band heater 39 stops, and the temperature of the heating cylinder 31 naturally drops to the ambient temperature over time. However, the set values ​​of "power OFF time", "threshold number of times Nth", "number of shots N", and "update flag" described later are held in the memory 62.

[0035] [Injection control processing] FIG. 3 is a flowchart of the injection control process. The injection control process is a process for molding one or more injection-molded products in sequence and supplying grease to a lubrication target at a predetermined timing. The control device 60 executes the injection control process shown in FIG. 3 in response to receiving an injection molding instruction from an operator through the display input device 67, for example. The injection molding instruction includes, for example, the number of injection-molded products to be molded. At the start of the injection control process, the heating cylinder 31 is assumed to be heated to a set temperature set through the display input device 67.

[0036] First, the control device 60 causes the injection molding machine 10 to execute an injection process (S11). The injection process is a process in which the screw 32 advances and retreats within the heating cylinder 31 to inject molten resin into the cavity. More specifically, the injection process is a process including the following steps.

[0037] First, the control device 60 rotates the injection motor 37 in the reverse direction and rotates the metering motor 38. As a result, the screw 32 moves backward while rotating, and the pellets supplied through the hopper 33 are filled (metered) into the resin passage 35 ahead of the screw 32 while being plasticized. The control device 60 also rotates the injection motor 37 in the forward direction. As a result, the screw 32 moves forward, and the plasticized molten resin ahead of the screw 32 is injected into the cavity of the mold 21 through the nozzle 36. Furthermore, the control device 60 drives the mold opening / closing motor 28 to open the mold 21, causes the robot arm (not shown) to take out the injection-molded product in the fixed mold 22, and drives the mold opening / closing motor 28 to clamp the mold 21.

[0038] Next, the control device 60 adds 1 to the number of shots N stored in the memory 62 in response to the execution of the injection process (S12). The number of shots N is a value indicating the number of times the injection process has been executed since the previous lubrication process was executed. At the start of the injection control process, the number of shots N is set to the value at the end of the previous injection control process. Next, the control device 60 compares the updated number of shots N with the threshold number of times Nth stored in the memory 62 (S13). The threshold number of times Nth is set to a value (e.g., 5000, 8000, 14000, 20000) indicating the frequency of execution of the lubrication process. The value of the threshold number of times Nth is updated in a threshold update process described later.

[0039] Next, when the number of shots N reaches the threshold number (S13: Yes), the control device 60 drives the grease pump 40 to execute a grease supply process to supply grease to the object to be lubricated (S14). The drive time of the grease pump 40 (in other words, the amount of grease supplied per time) may be a predetermined fixed value or may be a variable value according to the value of the threshold number of times Nth, the temperature detected by the temperature sensor 66a, etc. Then, the control device 60 initializes the number of shots N (=0) in response to the execution of the grease supply process (S15).

[0040] On the other hand, when the number of shots N is less than the threshold number of times Nth (S13: No), the control device 60 does not execute the processing of steps S14-S15. That is, when the number of shots N is less than the threshold number of times Nth (S13: No), the control device 60 does not execute the greasing process (S14). In other words, the control device 60 executes the greasing process (S14) every time the injection process is executed the threshold number of times Nth (S13: Yes).

[0041] Next, the control device 60 judges whether or not the number of injection-molded articles instructed in the injection molding instruction has been molded (S16). When the control device 60 judges that the number of injection-molded articles instructed in the injection molding instruction has not been molded (S16: No), it executes the processing from step S11 onwards again. That is, the control device 60 repeatedly executes the processing from step S11 to S16 the number of times corresponding to the number of injection-molded articles instructed in the injection molding instruction. Then, when the control device 60 judges that the number of injection-molded articles instructed in the injection molding instruction has been molded (S16: Yes), it ends the injection control processing.

[0042] [Threshold update process] Fig. 4 is a flowchart of the threshold update process. The threshold update process is a process for updating the threshold count Nth used in step S13 (in other words, for determining whether or not to perform the greasing process). When the injection molding machine 10 is in a power-on state, the control device 60 repeatedly executes the threshold update process shown in Fig. 4 at a predetermined time interval. It is assumed that the injection molding machine 10 is in a power-on state and the band heater 39 is in a powered state at the start of the threshold update process.

[0043] First, the control device 60 judges whether the injection molding machine 10 has been switched to the power OFF state (S21). Then, when the control device 60 judges that the injection molding machine 10 is still in the power ON state (S21: No), it does not execute the processes after step S21 and ends the threshold value update process. On the other hand, when the control device 60 judges that the injection molding machine 10 has been switched to the power OFF state (S21: Yes), it stores the current time in the memory 62 as the "power OFF time" (S22). As a result, the band heater 39 is switched to the non-energized state, and the temperature of the heating cylinder 31 gradually decreases.

[0044] The power OFF time is the time when the injection molding machine 10 is switched to the power OFF state (in other words, the time when the band heater 39 is switched to the non-energized state). If the band heater 39 is switched to the non-energized state while the injection molding machine 10 is still in the power ON state, the time may be stored in the memory 62.

[0045] Next, the control device 60 waits to execute the processes in and after step S24 until the injection molding machine 10 is switched to the power ON state again (S23: No). Then, when the injection molding machine 10 is switched to the power ON state (S23: Yes), the control device 60 compares the non-energized period P stored in the memory 62 with the threshold period Pth stored in the memory 62 (S24).

[0046] The non-energized period P is a period during which the band heater 39 is in a non-energized state. The non-energized period P is, for example, a value obtained by subtracting the power-off time from the current time. The threshold period Pth is a period from when the band heater 39 is switched to a non-energized state until the temperature of the nozzle 36 of the heating cylinder 31 (the temperature detected by the temperature sensor 66a) becomes approximately the same as the ambient temperature around the injection molding machine 10. The threshold period Pth may be a fixed value or a variable value.

[0047] If the non-energized period P is equal to or longer than the threshold period Pth (S24: Yes), the control device 60 updates the threshold number of times Nth in accordance with the temperature detected by the temperature sensor 66a (S25) and ends the threshold update process. As a result, the threshold number of times Nth updated in step S25 is used in the next step S13.

[0048] For example, the higher the temperature detected by the temperature sensor 66a, the lower the threshold number of times Nth (i.e., the higher the frequency of execution of the lubrication process). On the other hand, for example, the lower the temperature detected by the temperature sensor 66a, the higher the threshold number of times Nth (i.e., the lower the frequency of execution of the lubrication process). For example, when the temperature detected by the temperature sensor 66a is less than 25°C, the threshold number of times Nth is set to 20,000, when it is 25°C to 35°C, the threshold number of times Nth is set to 14,000, when it is 35°C to 45°C, the threshold number of times Nth is set to 8,000, and when it is 45°C or higher, the threshold number of times Nth is set to 5,000. However, the specific values ​​of the temperature and the threshold number of times Nth are not limited to the above-mentioned examples.

[0049] As one example, the case where the non-energized period P becomes equal to or longer than the threshold period Pth is when the injection molding machine 10 is test-driven (powered on) by the manufacturer, then installed in a delivery factory and the power is turned on again. As another example, the case where the non-energized period P becomes equal to or longer than the threshold period Pth is when the injection molding machine 10 that was operating (powered on) in one factory is moved to another factory and then the power is turned on again in the new factory. In this way, it is assumed that the threshold number Nth is updated when the installation environment of the injection molding machine 10 changes significantly.

[0050] On the other hand, when the non-energized period P is less than the threshold period Pth (S24: No), the control device 60 ends the threshold updating process without executing step S25. That is, when the non-energized period P is less than the threshold period Pth (S24: No), the control device 60 does not update the threshold number of times Nth. Note that a case where the non-energized period P is less than the threshold period Pth is assumed to be, for example, a short-time power-off state where the installation environment of the injection molding machine 10 does not change, such as a power outage or maintenance at the factory.

[0051] [Effects of this embodiment] According to the above embodiment, since the ambient temperature around the injection molding machine 10 is detected using the existing temperature sensor 66a for detecting the temperature of the heating cylinder 31, there is no need to install a new temperature sensor to update the threshold number of times Nth. Furthermore, when the installation environment of the injection molding machine 10 changes significantly, such as when the injection molding machine 10 is newly installed or relocated, the grease supply frequency can be appropriately set by updating the threshold number of times Nth.

[0052] Moreover, the higher the ambient temperature, the smaller the threshold number Nth. As a result, in an environment where grease deteriorates quickly, the frequency of the lubrication process can be increased to supply the required amount of grease to the object to be lubricated. On the other hand, the lower the ambient temperature, the larger the threshold number Nth. As a result, in an environment where grease deteriorates slowly, the frequency of the lubrication process can be reduced to prevent the injection molding machine 10 from being soiled with more grease than is necessary. In this way, according to the above embodiment, grease can be supplied to the object to be lubricated at an appropriate frequency according to the installation environment of the injection molding machine 10.

[0053] Furthermore, according to the above embodiment, the ambient temperature can be appropriately detected by detecting the ambient temperature using the temperature sensor 66a that is not covered among the multiple temperature sensors 66a to 66c that detect the temperature of the heating cylinder 31. However, the detection result of the temperature sensor 66a is not limited to the temperature sensor 66a, and the temperature sensors 66b and 66c may be used to update the threshold number Nth.

[0054] [Variations] With reference to FIG. 5, the modified examples of FIG. 3 and FIG. 4 will be described. FIG. 5 is a flow chart showing a modified example (A) of the process of step S25 and a modified example of the process of step S15. Note that a detailed description of the points in common with the above embodiment will be omitted, and the description will focus on the points of difference. The process according to the modified example differs from the above embodiment in the processes of steps S15 and S25, but has other processes in common with the above embodiment. Note that in the modified example, the threshold number of times Nth before being updated in the threshold update process will be referred to as the "first number of times Nth1", and the threshold number of times Nth newly determined in the threshold update process will be referred to as the "second number of times Nth2".

[0055] First, the control device 60 determines the second number of times Nth2 (S251). The method of determining the second number of times Nth2 in step S251 is the same as in step S25 of Fig. 4. In addition, the control device 60 compares the first number of times Nth1 (= the current threshold number of times Nth) with the second number of times Nth2 determined in step S251 (S252).

[0056] When the second number of times Nth2 is equal to or less than the first number of times Nth1 (S252: Yes), the control device 60 updates the threshold number of times Nth from the first number of times Nth1 to the second number of times Nth2 (S253). That is, when the second number of times Nth2 is equal to or less than the first number of times Nth1 (S252: Yes), the control device 60 updates the threshold number of times Nth from the first number of times Nth1 to the second number of times Nth2 (S253) before performing the next lubrication process (S14). In addition, the control device 60 sets the update flag to a second value "OFF" (S254).

[0057] On the other hand, when the second number of times Nth2 is greater than the first number of times Nth1 (S252: No), the control device 60 does not execute the processes of steps S253-S254, and sets the update flag to the first value "ON" (S255). That is, the threshold number of times Nth is maintained as the first number of times Nth1. In addition, the control device 60 stores the second number of times Nth2 determined in step S251 in the memory 62 separately from the threshold number of times Nth.

[0058] The update flag is a flag indicating whether or not the threshold number of times Nth needs to be updated in step S153 described later. The update flag is set to either a first value "ON" indicating that an update is necessary, or a second value "OFF" indicating that an update is not necessary. The update flag is stored in the memory 62.

[0059] In addition, the control device 60 compares the number of shots N with the threshold number of times Nth in step S13 of Fig. 3 (S13). Then, when the number of shots N reaches the threshold number of times Nth (S13: Yes), the control device 60 executes the process of step S14 and the process of Fig. 5 (B). That is, when the second number of times Nth2 determined in the threshold update process is equal to or smaller than the first number of times Nth1, the control device 60 executes the next greasing process using the second number of times Nth2 (S14). On the other hand, when the second number of times Nth2 determined in the threshold update process is greater than the first number of times Nth1, the control device 60 executes the next greasing process using the first number of times Nth1 (S14).

[0060] Next, the control device 60 initializes the number of shots N (=0) (S151). If the first value "ON" is set in the update flag (S152: Yes), the control device 60 updates the threshold number of times Nth from the first number of times Nth1 to the second number of times Nth2 (S153). If the second value "OFF" is set in the update flag (S252: Yes), the control device 60 sets the second value "OFF" in the update flag (S154). That is, if the second number of times Nth2 determined in the threshold update process is greater than the first number of times Nth1 (S252: No), the control device 60 executes the next greasing process (S14) using the first number of times Nth1, and then updates the threshold number of times Nth to the second number of times Nth2 (S153). On the other hand, if the second value "OFF" is set in the update flag (S152: No), the control device 60 does not execute the processes of steps S153-S154.

[0061] The second number of times Nth2 becomes larger than the first number of times Nth1 when the injection molding machine 10 is moved from an environment where grease deterioration is rapid to an environment where grease deterioration is slow. Therefore, if the second number of times Nth2 is used in the lubrication process immediately after the threshold update process, the grease may deteriorate too much. Therefore, according to the above-mentioned modified example, the first number of times Nth1 is used in the lubrication process immediately after the threshold update process, and the second number of times Nth2 is used in the lubrication process thereafter, so that the frequency of grease supply can be appropriately set.

[0062] The above-described embodiments are illustrative examples of the present invention, and are not intended to limit the scope of the present invention to these embodiments. Those skilled in the art can implement the present invention in various other forms without departing from the gist of the present invention. [Explanation of symbols]

[0063] 10... injection molding machine, 20... mold clamping device, 21... mold, 22... fixed side mold, 23... fixed die plate, 24... movable side mold, 25... movable die plate, 26... toggle link mechanism, 27... tie bar, 28... mold opening and closing motor, 30... injection device, 31... heating cylinder, 32... screw, 33... hopper, 34... hopper block, 35... resin passage, 36... nozzle, 37... injection motor, 38... metering motor, 39... band heater, 40... greasing pump, 60... control device, 61... CPU, 62... memory, 64... rotary encoder, 65... load cell, 66a, 66b, 66c... temperature sensor, 67... display input device

Claims

1. An injection molding machine including an injection device that injects a molding material into a cavity of a clamped mold and a control device that controls the injection device, The injection device is A heating cylinder filled with molding material; A heater for heating the heating cylinder; a screw that moves backward inside the heating cylinder to plasticize the molding material and moves forward inside the heating cylinder to inject the plasticized molding material into the cavity, A temperature sensor for detecting the temperature of the heating cylinder; and a lubrication pump for supplying a lubricant to the object to be lubricated. The control device includes: an injection process in which the plasticized molding material is injected into the cavity by moving the screw forward and backward; a lubrication process for supplying a lubricant to the object to be lubricated by driving the lubrication pump when the number of executions of the injection process reaches a threshold number of times; A threshold update process is executed to update the threshold number of times; The control device, in the threshold update process, determining whether a non-energized period during which the heater is not energized is equal to or longer than a threshold period when the injection molding machine is powered on; When the non-energization period is equal to or longer than the threshold period, the threshold number of times is updated in accordance with a temperature detected by the temperature sensor; When the non-energized period is less than the threshold period, the threshold number of times is not updated.

2. The control device, in the threshold update process, The higher the temperature detected by the temperature sensor, the smaller the threshold number of times is set.

2. The injection molding machine according to claim 1, wherein the threshold number of times is increased as the temperature detected by the temperature sensor decreases.

3. 2. The injection molding machine according to claim 1, wherein the temperature sensor detects the temperature of a nozzle provided at a tip of the heating cylinder.

4. The control device includes: A first number of times, which is the threshold number of times before being updated in the threshold updating process, is compared with a second number of times, which is the threshold number of times newly determined in the threshold updating process; When the second number of times is equal to or less than the first number of times, the threshold number of times is updated to the second number of times before the next lubrication process is performed; 2. The injection molding machine according to claim 1, wherein, when the second number of times is greater than the first number of times, the threshold number of times is updated to the second number of times after the next lubrication process is executed.

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