JP5654250B2 - Injection molding machine and injection molding method - Google Patents

Description

  The present invention relates to an injection molding machine and an injection molding method in which a molding process is realized by driving an electric motor.

  Injection molding in an injection molding machine typically involves a mold closing process for closing a mold, a mold clamping process for clamping a mold, a nozzle touch process for pressing a nozzle against a mold sprue, and a screw in a cylinder. Injecting the molten material collected in front of the screw into the mold cavity, then holding the pressure for a while to suppress the generation of bubbles and sink marks, and filling the mold cavity A plasticizing / metering process in which the screw is rotated for the next cycle during the time between the cooled molten material being cooled and solidified, and the resin is melted and accumulated in front of the cylinder, and the solidified molded article In order to take out the mold from the mold, it comprises a mold opening process for opening the mold and a molded product projecting process in which the molded product is pushed out by a projecting pin provided on the mold.

  Most of the electric power used in the electric injection molding machine is used for the electric motor except for the heater electric power provided around the heating cylinder in order to melt the resin. As motors incorporated in the electric injection molding machine, there are various electric motors such as an injection motor, a screw rotation motor, a mold opening / closing motor, and an ejector motor.

  2. Description of the Related Art Conventionally, a control method for controlling input to a motor incorporated in an injection molding machine is known in order to reduce power consumption of a motor used. In this control method, a setting value for holding the output of the motor for a predetermined setting time is set, a reduction ratio for decreasing the setting value with the passage of time is set, and a setting pattern is set based on the reduction ratio. Generate and control the input to the motor according to the setting pattern (see, for example, Patent Document 1).

Japanese Patent No. 4266224

  By the way, in general, the non-defective condition of a molded product varies to some extent according to customer needs, attributes (characteristics, etc.) of the molded product, price and the like. For example, some products are required to have a very high quality, while other products require a low price while having a certain level of quality. Therefore, when the drive pattern of the motor incorporated in the electric injection molding machine is set under the non-defective conditions on the safety side, it may be excessive quality for products that are required to be low in price while having some quality. This is an obstacle to cost reduction from the viewpoint of power consumption. On the other hand, if the drive pattern of the motor incorporated in the electric injection molding machine is set under the lowest-level non-defective conditions, the cost can be reduced from the viewpoint of power consumption for products that require extremely high quality. However, there is a possibility that the defect rate becomes high and the cost is increased.

  Therefore, an object of the present invention is to provide an injection molding machine and an injection molding method that can set the drive pattern of each motor in accordance with customer needs.

In order to achieve the above object, according to one aspect of the present invention, a plurality of molding steps constituting a molding cycle are independent of at least two steps realized by driving an electric motor. Mode setting means capable of selectively setting a mode and a second mode that consumes less power than the first mode;
In the molding process in which the first mode is set according to the mode setting state in the mode setting means, based on the first drive pattern, the electric motor provided corresponding to the molding process is controlled, In the molding step in which the second mode is set, control means for controlling an electric motor provided corresponding to the molding step based on a second drive pattern that consumes less power than the first drive pattern An injection molding machine is provided.

According to another aspect of the present invention, the first mode and the first mode independently of at least two steps realized by driving the electric motor among the plurality of molding steps constituting the molding cycle. A mode setting stage for selectively setting a second mode that consumes less power than the first mode;
In the molding process in which the first mode is set according to the mode setting state in the mode setting stage, the electric motor provided corresponding to the molding process is controlled based on the first drive pattern, In the molding process in which the second mode is set, a control stage for controlling an electric motor provided corresponding to the molding process based on a second drive pattern that consumes less power than the first drive pattern; An injection molding method is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the injection molding machine and the injection molding method which can set the drive pattern of each motor according to customer needs etc. are obtained.

It is a figure which shows the principal part structure of the injection molding machine 1 by one Example of this invention. It is a figure which shows an example of the combination of the drive pattern for power saving modes, and the drive pattern for normal modes. Another example of the combination of the drive pattern for the power saving mode and the drive pattern for the normal mode is shown. It is a flowchart which shows the flow of the main processes of an example of the injection molding method implement | achieved by the controller 26 of a present Example.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram showing a main configuration of an injection molding machine 1 according to an embodiment of the present invention. The injection molding machine 1 is an electric injection molding machine in this example, and includes a servo motor 11 for injection. The rotation of the servo motor 11 for injection is transmitted to the ball screw 12. A nut 13 that moves forward and backward by the rotation of the ball screw 12 is fixed to a pressure plate 14. The pressure plate 14 is movable along guide bars 15 and 16 fixed to a base frame (not shown). The forward / backward movement of the pressure plate 14 is transmitted to the screw 20 via the bearing 17, the load cell 18, and the injection shaft 19. The screw 20 is disposed in the heating cylinder 21 so as to be rotatable and movable in the axial direction. A hopper 22 for resin supply is provided at the rear portion of the screw 20 in the heating cylinder 21. Rotational motion of a screw rotating servomotor 24 is transmitted to the injection shaft 19 via a connecting member 23 such as a belt or a pulley. That is, the screw 20 is rotated when the injection shaft 19 is rotationally driven by the servo motor 24 for screw rotation.

  In the plasticizing / metering step, the molten resin is stored in the front portion of the screw 20, that is, the nozzle 21-1 side of the heating cylinder 21 by the screw 20 moving backward in the heating cylinder 21. In the injection process, molding is performed by filling the mold with molten resin stored in front of the screw 20 and pressurizing it. At this time, the force pushing the resin is detected by the load cell 18 as a reaction force. That is, the resin pressure at the front part of the screw is detected. The detected pressure is amplified by the load cell amplifier 25 and input to the controller 26 (control device) functioning as control means. In the pressure holding step, the resin filled in the mold is maintained at a predetermined pressure.

  A position detector 27 for detecting the amount of movement of the screw 20 is attached to the pressure plate 14. The detection signal of the position detector 27 is amplified by the amplifier 28 and input to the controller 26. This detection signal may also be used to detect the moving speed of the screw 20.

  The servo motors 11 and 24 are provided with encoders 31 and 32 for detecting the rotation speed, respectively. The rotation speeds detected by the encoders 31 and 32 are respectively input to the controller 26.

  The servo motor 42 is a servo motor for opening and closing the mold, and the servo motor 44 is a servo motor for projecting a molded product (ejector). The servo motor 42 drives a toggle link (not shown), for example, and realizes mold opening / closing. Moreover, the servo motor 44 implement | achieves molded article protrusion by moving an ejector rod (not shown) via a ball screw mechanism, for example. The servo motors 42 and 44 are provided with encoders 43 and 45 for detecting the rotational speed, respectively. The rotation speeds detected by the encoders 43 and 45 are respectively input to the controller 26.

  The controller 26 is mainly composed of a microcomputer, and includes, for example, a CPU, a ROM for storing control programs, a readable / writable RAM for storing calculation results, a timer, a counter, an input interface, an output interface, and the like. Have.

  The controller 26 sends current (torque) commands corresponding to a plurality of processes to the servo motors 11, 24, 42, 44. For example, the controller 26 controls the rotation speed of the servo motor 24 to realize the plasticizing / metering process. Further, the controller 26 controls the rotation speed of the servo motor 11 to realize the injection process and the pressure holding process. Similarly, the controller 26 controls the rotational speed of the servo motor 42 to realize the mold opening process and the mold closing process. The controller 26 controls the number of rotations of the servo motor 44 to realize a molded product protruding process.

  The input device 35 includes an input unit that allows the user to selectively set two modes for each of the mold opening / closing step, the pressure holding step, the plasticizing / metering step, and the molded product protruding step. The two modes are a normal mode and a power saving mode that consumes less power than the normal mode. Therefore, the user can selectively set the normal mode or the power saving mode for each of the mold opening / closing process, the pressure holding process, the plasticizing / metering process, and the molded product protruding process via the input device 35. Can do. For example, the user can set the normal mode for the mold opening / closing process, the pressure holding process, and the plasticizing / metering process via the input device 35, and can set the power-saving mode for the molded product protruding process. Further, for example, the user can set the pressure holding process and the plasticizing / metering process to the normal mode via the input device 35 and can set the mold opening / closing process and the molded product protruding process to the power saving mode. The mode setting (selection) via the input device 35 may be realized via a user interface such as a touch panel or operation buttons.

  If the user does not designate a special mode via the input device 35, the normal mode may be set as a default setting. This mode setting is typically executed in a trial stage before the start of mass production. However, mode setting (mode change) may be performed during mass production.

  A nonvolatile memory 50 is connected to the controller 26. The memory 50 may be provided outside the controller 26 or may be built in the controller 26. The memory 50 stores a drive pattern for the normal mode and a drive pattern for the power saving mode for each of the servomotors 11, 24, 42 and 44. These drive patterns may be prepared in advance by the manufacturer (designer) of the injection molding machine 1. Alternatively, the servo motors 11, 24, 42, 44 may be automatically generated by a predetermined algorithm in accordance with various setting values set in advance by the operator through the input device 35. Alternatively, the drive pattern for the normal mode may be prepared in advance by the manufacturer (designer) of the injection molding machine 1 for each of the servo motors 11, 24, 42, 44, and the drive pattern for the power saving mode is provided. Alternatively, it may be automatically generated by a predetermined algorithm based on the drive pattern for the normal mode. In a configuration in which various drive patterns are generated in advance by a manufacturer (designer) and are not generated (added) afterwards, a ROM in the controller 26 may be used instead of the memory 50.

  The driving pattern for the power saving mode may be an arbitrary pattern including a pattern described later as long as the driving pattern consumes less power than the driving pattern for the normal mode.

  FIG. 2 shows an example of a combination of a drive pattern for the power saving mode and a drive pattern for the normal mode. Here, the combination of the drive pattern for the power saving mode and the drive pattern for the normal mode used in the pressure holding process, that is, the combination of the drive pattern for the power saving mode and the drive pattern for the normal mode for the servo motor 11 will be described. To do. In FIG. 2, the shaded portion corresponds to the power reduction portion in the power saving mode.

  FIG. 2A shows a method of reducing the work amount of the motor by operating only the pressure. When the power saving mode is set for the pressure holding process by the input device 35, the controller 26 (control device) displays a pressure setting pattern in which the set pressure decreases from P to Pa while the set time T elapses. The same pressure setting pattern is generated or read from the memory 50, and the driver of the servo motor 11 is controlled so that electric power is supplied to the servo motor 31 according to the pressure setting pattern. On the other hand, when the normal mode is set for the pressure holding process by the input device 35, the controller 26 (control device) sets the pressure so that the set pressure maintains P over the entire period of the set time T. A pattern is generated or the pressure setting pattern is read from the memory 50, and the driver of the servo motor 11 is controlled so that electric power is supplied to the servo motor 31 according to the pressure setting pattern.

  FIG. 2B shows a method for reducing the work of the motor by controlling only the time. When the power saving mode is set for the pressure holding process by the input device 35, the controller 26 (control device) generates a pressure setting pattern in which the pressure decreases from time T1 to time T or from the memory 50. The pressure setting pattern is read out, and the driver of the servo motor 11 is controlled so that electric power is supplied to the servo motor 31 according to the pressure setting pattern. On the other hand, when the normal mode is set for the pressure holding process by the input device 35, the controller 26 (control device) maintains the pressure constant over the entire pressure holding period including the period from time T1 to time T. The pressure setting pattern is generated or the pressure setting pattern is read from the memory 50, and the driver of the servo motor 11 is controlled so that electric power is supplied to the servo motor 31 according to the pressure setting pattern.

  Note that a power saving pattern combining the power consumption reduction method (pressure operation) shown in FIG. 2A and the power consumption reduction method (time operation) shown in FIG. 2B may be used. Further, the drive pattern for the power saving mode may be a pattern in which the maximum value (P in the example of FIG. 2) of the set pressure for holding pressure is smaller than the drive pattern for the normal mode.

  FIG. 3 shows another example of the combination of the drive pattern for the power saving mode and the drive pattern for the normal mode. Here, the combination of the drive pattern for the power saving mode and the drive pattern for the normal mode used in the plasticizing / weighing process, that is, the combination of the drive pattern for the servo motor 24 and the drive pattern for the normal mode. Will be described. 3A shows a drive pattern for the normal mode, and FIG. 3B shows a drive pattern for the power saving mode.

  As shown in FIG. 3A, the drive pattern for the normal mode is such that the rotational speed of the screw 20 becomes a predetermined set speed V1 over the entire period from the start to the end of the plasticizing / metering process. It may be a simple driving pattern. As shown in FIG. 3B, the drive pattern for the power saving mode is such that the rotational speed of the screw 20 gradually increases from zero to a predetermined set speed V1 at the start of the plasticizing / metering process. It may be a pattern in which the rotational speed of the screw 20 gradually decreases from a predetermined set speed V1 to zero at the end of the weighing process. In this case, in order to realize the same amount of rotation of the screw 20 in the normal mode and in the power saving mode, the total driving time is longer in the power saving mode, but the pattern for the power saving mode is A power saving effect can be obtained as much as there is no power loss due to steep rise and fall in the drive pattern for the normal mode. As another example, the drive pattern for the power saving mode may be a pattern having a lower set speed V1 than the drive pattern for the normal mode.

  Here, the combination of the drive pattern for the power saving mode and the drive pattern for the normal mode used in the pressure holding process and the plasticizing / metering process has been described with reference to FIGS. 2 and 3. Each driving pattern based on the same concept may be used for the mold opening / closing process and the molded product protruding process.

  FIG. 4 is a flowchart showing a flow of main processing of an example of an injection molding method realized by the controller 26 of the present embodiment.

  In step 400, the controller 26 reads the mode setting state set by the user via the input device 35. In this example, as described above, the controller 26 reads the mode setting state for each of the mold opening / closing process, the pressure holding process, the plasticizing / metering process, and the molded product protruding process.

  In step 402, the controller 26 determines whether or not the next process (the process that is about to start execution) is the target process, that is, the mold opening / closing process, the pressure holding process, the plasticizing / metering process, and the protruding part. It is determined whether it is any of the processes. If the process to be performed next is the target process, the process proceeds to step 402. On the other hand, when the process to be performed next is a process other than the target process (for example, a mold clamping process), the controller 26 executes the process in a normal manner (step 403).

  In step 404, the controller 26 determines whether the normal mode is set for the target process or the power saving mode is set. In this determination, the determination result of the mode setting state in step 400 is used. When the normal mode is set for the target process, the process proceeds to step 406, and when the power saving mode is set for the target process, the process proceeds to step 408.

  In step 406, in the target process determined in step 404, the servo motors 11, 24, 42 or 44 used in the target process are controlled based on the drive pattern for the normal mode.

  In step 408, in the target process determined in step 404, the servo motors 11, 24, 42 or 44 used in the target process are controlled based on the drive pattern for the power saving mode.

  In step 410, the controller 26 determines whether or not all processes have been completed. When all the processes are finished, the current molding process is finished. In this case, the controller 26 may return to step 402 for the next molding process, or may start again from step 400 when the mode setting state is changed. When all the processes are not completed (for example, when the pressure holding process is completed), the process proceeds to step 402 for the next process.

  According to the injection molding machine 1 of the present embodiment described above, the following excellent effects are achieved, among others.

As described above, according to the injection molding machine 1 of the present embodiment, the normal mode and power saving are performed independently of each other in the mold opening / closing process, the pressure holding process, the plasticizing / metering process, and the molded product protruding process. Any of the modes can be selectively set by the user. Thus, various combinations (in this case, the combination of types 2 ⁴⁾ it is possible to realize, it is possible to meet various needs of users.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Can be added.

  For example, in the above-described embodiment, two modes of the normal mode and the power saving mode can be set, but three or more modes having different power consumptions may be set. Also, the number of modes that can be set for each process may be different, for example, two modes can be set for a certain process, and three modes can be set for a certain process.

  Further, in the above-described embodiment, the user selectively sets one of the normal mode and the power saving mode in the four molding processes of the mold opening / closing process, the pressure holding process, the plasticizing / metering process, and the molded product protruding process. However, the molding process in which the user can selectively set either the normal mode or the power saving mode only needs to include two or more molding processes. Further, the molding process in which the user can selectively set either the normal mode or the power saving mode may include a molding process (a mold clamping process or an injection process) other than the above-described molding process.

DESCRIPTION OF SYMBOLS 1 Injection molding machine 11 Servo motor 12 Ball screw 13 Nut 14 Pressure plate 15, 16 Guide bar 17 Bearing 18 Load cell 19 Injection shaft 20 Screw 21 Heating cylinder 22 Hopper 23 Connecting member 24 Servo motor 26 Controller 27 Position detector 28 Amplifiers 31, 32 Encoder 35 Input device 42 Servo motor 44 Servo motors 43 and 45 Encoder 50 Memory

Claims (2)

Independently of at least two steps realized by driving the electric motor among the plurality of forming steps constituting the forming cycle, the first mode and the second power consumption is smaller than that in the first mode. Mode setting means capable of selectively setting the mode;
In the molding process in which the first mode is set according to the mode setting state in the mode setting means, based on the first drive pattern, the electric motor provided corresponding to the molding process is controlled, In the molding step in which the second mode is set, control means for controlling an electric motor provided corresponding to the molding step based on a second drive pattern that consumes less power than the first drive pattern An injection molding machine comprising: Independently of at least two steps realized by driving the electric motor among the plurality of forming steps constituting the forming cycle, the first mode and the second power consumption is smaller than that in the first mode. A mode setting stage for selectively setting the mode;
In the molding process in which the first mode is set according to the mode setting state in the mode setting stage, the electric motor provided corresponding to the molding process is controlled based on the first drive pattern, In the molding process in which the second mode is set, a control stage for controlling an electric motor provided corresponding to the molding process based on a second drive pattern that consumes less power than the first drive pattern; An injection molding method comprising:

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