JP2016185692A - Injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection molding machine that can assist in adjusting the balance of axial force.SOLUTION: An injection molding machine has a plurality of tie bars that elongate according to clamping force, and a controller that controls the axial force of the tie bar, where the controller calculates a set value on an input of operation to change the axial force, on the basis of a set value on the balance of the axial force. The controller also calculates a set value on the input of operation, on the basis of how a changed setting on the input of operation influences the balance of the axial force. The controller further acquires an actual value of the balance of the axial force, and calculates the set value on the input of operation on the basis of the set value of the balance of the axial force and its actual value.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an injection molding machine.

  The injection molding machine has a mold clamping device that performs mold closing, mold clamping, and mold opening of a mold apparatus. The mold clamping device has a plurality of tie bars extending according to the mold clamping force (see, for example, Patent Document 1). Clamping force is distributed over multiple tie bars, and the tie bars stretch. The force that resists tie bar elongation is called axial force. When there is a difference in the effective length of a plurality of tie bars, a difference occurs in axial force between a tie bar having a short effective length and a tie bar having a long effective length. Here, the effective length of the tie bar refers to an interval between members connected by the tie bar, and is measured, for example, in a state where a mold clamping force is not applied. The balance of the axial force can be adjusted by adjusting the effective length of the tie bar.

JP 2004-249637 A

  When the effective length of one tie bar is adjusted, the distribution of mold clamping force changes, and the axial force of all tie bars can change. Therefore, it is complicated to set the effective length of each tie bar so that the balance of the axial force becomes the target balance.

  The present invention has been made in view of the above problems, and a main object of the present invention is to provide an injection molding machine capable of supporting adjustment of the balance of axial force.

In order to solve the above problems, according to one aspect of the present invention,
Multiple tie bars that extend according to the clamping force,
A controller for controlling the axial force of the tie bar,
An injection molding machine is provided in which the controller calculates a set value of an operation amount for changing the axial force based on a set value of the balance of the axial force.

  According to one aspect of the present invention, there is provided an injection molding machine that can assist in adjusting the balance of axial force.

It is a figure which shows the state at the time of mold opening completion of the injection molding machine by one Embodiment. It is a figure which shows the state at the time of the mold clamping of the injection molding machine by one Embodiment. It is a figure which shows the positional relationship of the tie bar of the injection molding machine by one Embodiment, Comprising: It is the figure which looked at the fixed platen from the movable platen side. It is a figure which shows the operation screen of the injection molding machine by one Embodiment. It is a figure which shows the controller by one Embodiment. It is a figure which shows the axial force estimation part of the controller by one Embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In each of the drawings, the same or corresponding components are denoted by the same or corresponding reference numerals, and description thereof will be omitted.

  FIG. 1 is a diagram illustrating a state when mold opening of an injection molding machine according to an embodiment is completed. FIG. 2 is a diagram illustrating a state during mold clamping of the injection molding machine according to the embodiment. The injection molding machine includes a frame Fr, a mold clamping device 10, an operation device 70, a display device 80, a controller 90, and the like.

  The controller 90 includes a central processing unit (CPU) 91 and a storage medium 92 such as a memory. The controller 90 controls the mold clamping device 10, the operation device 70, the display device 80, and the like by causing the CPU 91 to execute a program stored in the storage medium 92.

  The mold clamping apparatus 10 performs mold closing, mold clamping, and mold opening of the mold apparatus 30. The mold clamping device 10 includes a fixed platen 12, a movable platen 13, a rear platen 15, a tie bar 16, a toggle mechanism 20, and a mold clamping motor 21. Hereinafter, the moving direction of the movable platen 13 when the mold is closed (right direction in FIGS. 1 and 2) is assumed to be the front, and the moving direction of the movable platen 13 when the mold is opened (left direction in FIGS. 1 and 2) is assumed to be the rear. To do.

  The fixed platen 12 is fixed to the frame Fr. A fixed mold 32 is attached to a surface of the fixed platen 12 facing the movable platen 13.

  The movable platen 13 is movable along a guide (for example, a guide rail) 17 laid on the frame Fr, and is movable forward and backward with respect to the fixed platen 12. A movable mold 33 is attached to the surface of the movable platen 13 facing the fixed platen 12.

  By moving the movable platen 13 back and forth with respect to the fixed platen 12, mold closing, mold clamping, and mold opening are performed. The fixed mold 32 and the movable mold 33 constitute a mold apparatus 30.

  The rear platen 15 is connected to the fixed platen 12 at an interval, and is placed on the frame Fr so as to be movable in the mold opening / closing direction. The rear platen 15 may be movable along a guide laid on the frame Fr. The guide of the rear platen 15 may be the same as the guide 17 of the movable platen 13.

  In this embodiment, the fixed platen 12 is fixed to the frame Fr, and the rear platen 15 is movable in the mold opening / closing direction with respect to the frame Fr. However, the rear platen 15 is fixed to the frame Fr, and the fixed platen 12 is The frame Fr may be movable in the mold opening and closing direction.

  The tie bar 16 connects the fixed platen 12 and the rear platen 15 with an interval. A plurality of tie bars 16 are used. Each tie bar 16 is parallel to the mold opening / closing direction and extends in accordance with the mold clamping force.

  The toggle mechanism 20 is disposed between the movable platen 13 and the rear platen 15. The toggle mechanism 20 includes a cross head 20a and a plurality of links 20b and 20c. One link 20b is swingably attached to the movable platen 13, and the other link 20c is swingably attached to the rear platen 15. These links 20b and 20c are connected so as to be able to bend and stretch with pins or the like. By moving the cross head 20 a back and forth, the plurality of links 20 b and 20 c are bent and extended, and the movable platen 13 is moved back and forth with respect to the rear platen 15.

  The mold clamping motor 21 is attached to the rear platen 15 and moves the movable platen 13 forward and backward by moving the cross head 20a forward and backward. Between the mold clamping motor 21 and the cross head 20a, there is provided a motion conversion mechanism that converts the rotational motion of the mold clamping motor 21 into a linear motion and transmits the linear motion to the cross head 20a. The motion conversion mechanism is constituted by, for example, a ball screw mechanism.

  The operation of the mold clamping device 10 is controlled by the controller 90. The controller 90 controls a mold closing process, a mold clamping process, a mold opening process, and the like.

  In the mold closing process, the movable mold 33 is brought into contact with the fixed mold 32 by driving the mold clamping motor 21 and moving the movable platen 13 forward.

  In the mold clamping process, a mold clamping force is generated by further driving the mold clamping motor 21. A cavity space is formed between the movable mold 33 and the fixed mold 32 during mold clamping, and the cavity space is filled with a liquid molding material. The molding material in the cavity space is solidified and becomes a molded product.

  In the mold opening process, the movable mold 33 is moved away from the fixed mold 32 by driving the mold clamping motor 21 to retract the movable platen 13.

  The mold clamping device 10 of the present embodiment has the mold clamping motor 21 as a drive source for moving the movable platen 13, but may have a hydraulic cylinder instead of the mold clamping motor 21. Moreover, the mold clamping device 10 may have a linear motor for mold opening and closing and may have an electromagnet for mold clamping.

  FIG. 3 is a view showing the positional relationship of the tie bars of the injection molding machine according to the embodiment, and is a view of the fixed platen viewed from the movable platen side. The injection molding machine has four tie bars 16. The four tie bars 16 are arranged vertically symmetrically about the horizontal line L1 and symmetrically arranged about the vertical line L2 when viewed in the mold opening / closing direction. The upper side of the horizontal line L1 is called the top side, and the lower side of the horizontal line L1 is called the ground side. Further, the operation device 70 side from the vertical line L2 is referred to as an operation side, and the side opposite to the operation device 70 from the vertical line L2 is referred to as a non-operation side.

  The mold clamping force is distributed and applied to the four tie bars 16, and each tie bar 16 extends. The force that resists the elongation of each tie bar 16 is called an axial force. When there is a difference in the effective lengths of the four tie bars 16, there is a difference in axial force between the tie bar 16 having a short effective length and the tie bar 16 having a long effective length. Here, the effective length of the tie bar 16 refers to the distance between the fixed platen 12 and the rear platen 15 connected by the tie bar 16, and is measured, for example, in a state where no mold clamping force is applied.

  The balance of the axial force can be adjusted by adjusting the effective length of the tie bar 16. The balance of the axial force is set so that, for example, the surface pressure between the fixed mold 32 and the movable mold 33 becomes a target distribution during mold clamping. The target distribution may be either a uniform distribution or a non-uniform distribution, and is set according to the situation. Molding defects can be reduced.

  Since the tie bar 16 is formed of a metal material, the effective length of the tie bar 16 varies depending on the temperature of the tie bar 16. The higher the temperature of the tie bar 16, the longer the effective length of the tie bar 16. By adjusting the temperature of the tie bar 16, the effective length of the tie bar 16 can be adjusted, and the balance of the axial force can be adjusted.

  Therefore, as shown in FIGS. 1 and 2, an axial force detector 22, a temperature adjuster 23, a temperature detector 24, and the like are attached to each tie bar 16. The axial force detector 22, the temperature adjuster 23, the temperature detector 24, and the like are provided in the mold clamping device 10.

  The axial force detector 22 detects the axial force of the tie bar 16. The axial force detector 22 is, for example, a strain gauge type, and detects the axial force of the tie bar 16 by detecting distortion of the tie bar 16. The axial force detector 22 outputs the detection result to the controller 90.

  The controller 90 sets the temperature of the tie bar 16 so that the actual balance value of the axial force becomes the set value. This setting method will be described later.

  The axial force detector 22 of the above embodiment is a strain gauge type, but may be a piezoelectric type, a capacitive type, a hydraulic type, an electromagnetic type, or the like.

  The temperature controller 23 adjusts the temperature of the tie bar 16. The portion of the tie bar 16 where the temperature is adjusted by the temperature controller 23 is referred to as a temperature adjustment unit. The temperature adjuster 23 includes a heater such as a heater, and adjusts the temperature of the temperature adjuster of the tie bar 16 by heating.

  The temperature adjuster 23 may include a cooler such as a water cooling jacket, and may adjust the temperature of the temperature adjusting unit of the tie bar 16 by cooling. The temperature controller 23 may include both a heater and a cooler.

  The controller 90 controls the temperature regulator 23 so that the actual temperature value of the temperature adjustment unit of the tie bar 16 becomes a set value. The control may be either feedback control or feedforward control.

  By the way, if the temperature of the temperature adjusting portion of one tie bar 16 is changed and the effective length thereof is adjusted, the distribution of mold clamping force changes, and the axial force of all tie bars can change. Further, when the temperature of the temperature adjusting unit of one tie bar 16 is changed, the temperature of other tie bars can be changed by the movement of heat.

  Therefore, the controller 90 manages the balance of the axial force instead of managing the axial force of each tie bar 16 individually. Thereby, although mentioned later in detail, adjustment of the balance of axial force can be supported.

  The controller 90 may manage the axial force balance and may manage each axial force individually.

  The controller 90 is connected to the operation device 70 and the display device 80. The operation device 70 and the display device 80 may be configured with a touch panel, for example, and may be integrated. The operation device 70 receives an input operation by the user and outputs a signal corresponding to the input operation to the controller 90. The display device 80 displays an operation screen corresponding to an input operation on the operation device 70 under the control of the controller 90. The operation screen is used for setting the injection molding machine. A plurality of operation screens are prepared and displayed by switching or overlapping. The user sets the injection molding machine by operating the operation device 70 while viewing the operation screen displayed on the display device 80.

  In addition, although the operating device 70 and the display device 80 of this embodiment are integrated, you may provide independently. A plurality of operation devices 70 may be provided.

  FIG. 4 is a diagram illustrating an operation screen of the injection molding machine according to the embodiment. The operation screen has an axial force balance display portion 82. The axial force balance display unit 82 displays the balance of axial force. Therefore, it is easier for the user to grasp and adjust the surface pressure distribution between the fixed mold 32 and the movable mold 33 than when displaying each axial force individually. Here, the balance of the axial force means the degree of variation in the axial force, and may be expressed by, for example, a difference in axial force. The difference in axial force may be expressed as a percentage (%) of the average axial force.

  Note that the operation screen may further include an axial force display unit that individually displays each axial force.

  The axial force balance display unit 82 includes a horizontal axial force balance display unit 83 and a vertical axial force balance display unit 84. The horizontal axial force balance display unit 83 and the vertical axial force balance display unit 84 may be displayed simultaneously on the operation screen. The balance in two directions is visible.

  The horizontal axial force balance display unit 83 displays the balance of axial force in the horizontal direction (hereinafter also referred to as horizontal axial force balance). The horizontal axial force balance is expressed, for example, by the difference between the average value of the axial forces of the two tie bars 16 on the operation side and the average value of the axial forces of the two tie bars 16 on the non-operation side. This difference may be expressed as a percentage (%) of the average value of all axial forces. In the case of the ratio, there is no fluctuation due to the size of the clamping force.

  When the value of the horizontal axial force balance is Nh (%), the average value of the axial force on the operating side is 100 + Nh / 2 (%), and the average value of the axial force on the non-operating side is 100-Nh / 2 (%). . A positive value Nh of the horizontal axial force balance means that the average value of the axial force on the operating side is larger than the average value of the axial force on the non-operating side. On the other hand, the negative value Nh of the horizontal axial force balance means that the average value of the operating side axial force is smaller than the average value of the counter operating side axial force.

  It should be noted that the relationship between the positive / negative value of the horizontal axial force balance and the magnitude of the axial force on the operating side and the axial force on the non-operating side may be reversed.

  The horizontal axial force balance display unit 83 includes a set value display unit 83a and an actual value display unit 83b. The set value display part 83a displays the set value of the horizontal axial force balance. The actual value display part 83b displays the actual value of the horizontal axial force balance. The set value display part 83a and the actual value display part 83b may be simultaneously displayed on the operation screen. A deviation between the set value and the actual value can be visually recognized.

  The user operates the operation device 70 while looking at the operation screen, thereby inputting the set value of the horizontal axial force balance to the set value display portion 83a. The controller 90 sets the temperature of the tie bar 16 so that the actual value of the horizontal axial force balance becomes a set value.

  The vertical axial force balance display unit 84 displays the axial force balance in the vertical direction (hereinafter also referred to as vertical axial force balance). The vertical axial force balance is expressed, for example, by the difference between the average value of the axial force of the two tie bars 16 on the top side and the average value of the axial force of the two tie bars 16 on the ground side. This difference may be expressed as a percentage (%) of the average value of all axial forces. In the case of the ratio, there is no fluctuation due to the size of the clamping force.

  When the value of the vertical axial force balance is Nv (%), the average value of the axial force on the top side is 100 + Nv / 2 (%), and the average value of the axial force on the ground side is 100-Nv / 2 (%). A positive value Nv of the vertical axial force balance means that the average value of the axial force on the top side is larger than the average value of the axial force on the ground side. On the other hand, the negative value Nv of the vertical axial force balance means that the average value of the axial force on the top side is smaller than the average value of the axial force on the ground side.

  The relationship between the positive / negative value of the vertical axial force balance and the magnitude of the axial force on the top side and the axial force on the ground side may be reversed.

  The vertical axial force balance display unit 84 includes a set value display unit 84a and an actual value display unit 84b. The set value display portion 84a displays the set value of the vertical axial force balance. The actual value display part 84b displays the actual value of the vertical axial force balance. The set value display part 84a and the actual value display part 84b may be simultaneously displayed on the operation screen. A deviation between the set value and the actual value can be visually recognized.

  The user operates the operation device 70 while viewing the operation screen to input the set value of the vertical axial force balance to the set value display unit 84a. The controller 90 sets the temperature of the tie bar 16 so that the actual value of the vertical axial force balance becomes a set value.

  FIG. 5 is a diagram illustrating a controller according to an embodiment. As shown in FIG. 5, the controller 90 calculates the temperature setting value of the temperature adjustment unit of the tie bar 16 as an operation amount for changing the axial force, based on the axial force balance setting value or the like.

  The controller 90 includes an axial force setting unit 101, an axial force measurement unit 102, a non-interference calculation unit 103, a temperature setting unit 104, a temperature measurement unit 105, and a temperature adjustment command unit 106.

  The axial force setting unit 101 obtains a setting value of the balance of axial force. For example, the axial force setting unit 101 uses the operation screen to acquire a horizontal axial force balance set value and a vertical axial force balance set value. The balance of the axial force may be represented by the degree of variation in axial force, for example, the difference in axial force. The difference in axial force may be expressed as a percentage (%) of the average axial force. In the case of the ratio, there is no fluctuation due to the size of the clamping force.

  The axial force measuring unit 102 uses the axial force detector 22 to measure the actual value of the axial force of each tie bar 16.

  The non-interference calculation unit 103 obtains the actual value of the axial force balance based on the measurement result of the axial force measurement unit 102. For example, the non-interference calculation unit 103 calculates the actual value of the horizontal axial force balance and the actual value of the vertical axial force balance.

  The temperature setting unit 104 calculates the set value of the temperature of the temperature adjustment unit of each tie bar 16 based on the set value of the balance of axial force and the like (the difference between the set value and the actual value in FIG. 5). Compared with the case where this calculation is performed based on the set value of each axial force, the influence of the temperature setting change of the temperature control unit of one tie bar 16 on the axial force of the other tie bar 16 is easier to handle. It is easy to set the temperature of the 16 temperature control units. Although details will be described later, an estimated value of axial force balance may be used instead of the actual value of axial force balance.

The temperature setting unit 104 is, for example,
T0 + Th + Tv, the temperature of the temperature adjustment part of the tie bar 16 on the operation side and the top side,
The temperature of the temperature control part of the tie bar 16 on the operation side and the ground side is set to T0 + Th−Tv,
The temperature of the temperature control part of the tie bar 16 on the non-operation side and the top side is set to T0−Th + Tv,
The temperature of the temperature control part of the tie bar 16 on the non-operation side and the ground side is T0-Th-Tv.
And T0 (° C.), Th (° C.), and Tv (° C.) may be set. T0 is the average value (° C.) of the temperature control unit of all tie bars 16, Th is the temperature balance (difference) of the temperature control unit in the horizontal direction, and Tv is the temperature balance (difference) of the temperature control unit in the vertical direction. Respectively.

  The temperature setting unit 104 calculates the set value of the temperature of the temperature adjustment unit of each tie bar 16 based on the influence of the change in the temperature setting of the temperature adjustment unit of the tie bar 16 on the axial force balance as the operation amount. Also good. It is possible to consider the influence that the temperature setting change of the temperature control unit of one tie bar 16 has on the axial force of another tie bar 16. The above-mentioned influence is obtained in advance by experiments and simulations, and what is stored in the storage medium 92 is read out and used. The influence may be stored in the storage medium 92 in the form of a formula or a table.

  The temperature measurement unit 105 uses the temperature detector 24 to measure the actual value of the temperature of the temperature adjustment unit of the tie bar 16.

  The temperature adjustment command unit 106 generates a command for each temperature controller 23 based on the temperature setting value of the temperature adjustment unit of the tie bar 16 (the difference between the setting value and the actual value in FIG. 5).

  As described above, the controller 90 calculates the temperature setting value of the temperature adjustment unit of the tie bar 16 as the operation amount for changing the axial force based on the axial force balance setting value or the like. This set value is calculated for each tie bar 16. The controller 90 generates a command for the temperature regulator 23 based on the calculated set value and the like. This command is generated for each temperature controller 23.

  By the way, it takes time until the actual temperature value of the temperature control unit of the tie bar 16 reaches the set value. Further, even after the actual value is stabilized at the set value, it takes time until the temperature distribution of the entire mold clamping apparatus 10 is stabilized. Furthermore, the actual value of the axial force can be measured only at the time of mold clamping, and cannot always be measured.

  Therefore, the controller 90 may include an axial force estimation unit 107 (see FIG. 6). The axial force estimating unit 107 estimates the axial force based on the temperature of the temperature adjusting unit of the tie bar 16 as an operation amount for changing the axial force.

  The controller 90 appropriately controls the temperature regulator 23 using the estimated axial force value instead of the actual axial force value even when the actual axial force value cannot be measured by the axial force measuring unit 102 shown in FIG. it can. Therefore, the time until the axial force of the tie bar 16 is stabilized can be shortened.

  For example, as shown in FIG. 6, the axial force estimation unit 107 includes an axial force calculation unit 108 and a calculation correction unit 109.

  The axial force calculation unit 108 calculates the axial force based on the temperature of the temperature adjustment unit of the tie bar 16 as an operation amount for changing the axial force. The axial force calculation unit 108 may use the actual temperature value of the temperature adjusting unit for calculating the axial force.

  In addition, although the axial force calculation part 108 of this embodiment uses the actual value of the temperature of the said temperature control part for calculation of axial force, you may use the setting value of the temperature of the said temperature control part.

  The axial force calculation unit 108 uses, for example, a finite element method for calculating the axial force. According to the finite element method, the time change of the temperature distribution of the mold clamping device 10 can be calculated, and each axial force can be calculated.

  In addition, although the axial force calculation part 108 of this embodiment uses a finite element method for calculation of axial force, you may use the heat transfer model created based on the thermal diffusion equation etc. Specific heat, heat transfer coefficient, etc. are used for calculation of axial force.

  The axial force calculation unit 108 may calculate the current value (instantaneous value) of the axial force or may calculate the axial force in a transient state. Here, the transient state refers to a state from the start of control of the temperature regulator 23 until the temperature distribution of the entire mold clamping device 10 is stabilized.

  The current value is not limited to a value in a transient state, and may be a value in a steady state. Here, the steady state refers to a state in which the actual temperature value of the temperature adjusting unit of the tie bar 16 is stabilized at the set value, and the temperature distribution of the entire mold clamping device 10 is stable.

  The axial force calculation unit 108 may calculate, for example, a future value (for example, a steady value) of the axial force instead of the current value of the axial force.

  The axial force calculation unit 108 may have the function of the non-interference calculation unit 103 illustrated in FIG. 5 and may calculate the balance of axial force. The balance of the axial force may be represented by the degree of variation in axial force, for example, the difference in axial force. The difference in axial force may be expressed as a percentage (%) of the average axial force. In the case of the ratio, there is no fluctuation due to the size of the clamping force.

  The axial force calculation unit 108 calculates, for example, a horizontal axial force balance and a vertical axial force balance. The controller 90 can simultaneously adjust the balance in the two directions. The controller 90 may adjust the balance of axial force in only one direction, and the axial force calculation unit 108 may calculate the balance of axial force in only one direction.

  The calculation correction unit 109 corrects the calculated value of the axial force calculated by the axial force calculation unit 108 based on the actual value of the axial force. Thereby, the axial force estimation accuracy by the axial force estimation unit 107 can be increased.

  For example, the calculation correction unit 109 calculates a compensation value to be added to the input value of the axial force calculation unit 108. The calculation correction unit 109 calculates a temperature compensation value based on the difference between the actual value of the axial force measured at the time of mold clamping and the calculated value of the axial force. The calculated axial force value can be corrected by adding the temperature compensation value to the actual temperature value. This temperature compensation value may be used until the next measurement of the actual value of axial force, and may be updated each time the actual value of axial force is measured.

  The calculation correction unit 109 of this embodiment calculates a compensation value to be added to the input value of the axial force calculation unit 108, but may calculate a compensation value to be added to the output value of the axial force calculation unit 108.

  The embodiments of the injection molding machine have been described above, but the present invention is not limited to the above embodiments and the like, and various modifications are possible within the scope of the gist of the present invention described in the claims. Improvements are possible.

  For example, in the above embodiment, the axial force detector 22, the temperature adjuster 23, and the temperature detector 24 are attached to all the tie bars 16, but may be attached to only some of the tie bars 16. For example, when the controller 90 adjusts both the vertical axial force balance and the horizontal axial force balance, the temperature controller 23 and the temperature detector 24 may be attached to only three of the four tie bars 16. . Further, when the controller 90 adjusts only the vertical axial force balance, the temperature controller 23 and the temperature detector 24 may be attached only to the tie bar 16 on one side of the top side and the ground side. When the controller 90 adjusts only the vertical axial force balance, the axial force detector 22 is attached to one of the top two tie bars 16 and one of the two ground tie bars 16, respectively. Also good.

  Moreover, in the said embodiment, although the balance of axial force is represented by the difference of axial force, you may represent it by ratio of axial force. For example, the vertical axial force balance may be represented by a ratio between the average value of the axial force on the top side and the average value of the axial force on the ground side. Similarly, the horizontal axial force balance may be represented by a ratio between an average value of the axial force on the operation side and an average value of the axial force on the non-operation side.

  Moreover, although the controller 90 of the said embodiment uses the temperature of the tie bar 16 as an operation amount which changes an axial force, you may use the effective length of the tie bar 16. FIG. For adjusting the effective length of the tie bar 16, for example, a male screw 41 formed on the tie bar 16, a female screw 42 screwed to the male screw 41, and a rotation motor (not shown) for rotating the female screw 42 are used. It is done. The female screw 42 is attached to the rear platen 15 so as not to advance and retreat and to be rotatable. The controller 90 adjusts the effective length of the tie bar 16 by controlling the rotation of the rotary motor. The female screw 42 may be attached to either of the two members (the fixed platen 12 and the rear platen 15 in the above embodiment) to which the tie bar 16 is connected, or may be attached to both. As the operation amount for changing the axial force, both the temperature of the tie bar 16 and the effective length of the tie bar 16 may be used. The temperature of the tie bar 16 can also be adjusted by increasing or decreasing the power supplied to the heater that heats the tie bar 16. Therefore, the power supplied to the heater may be used as an operation amount for changing the axial force.

  The mold clamping device 10 of the above embodiment is a horizontal mold whose mold opening / closing direction is a horizontal direction, but may be a vertical mold whose mold opening / closing direction is a vertical direction. The vertical mold clamping device includes a lower platen as a fixed platen, an upper platen as a movable platen, a toggle support, a toggle mechanism, and a tie bar. A lower mold is attached to the lower platen, and an upper mold is attached to the upper platen. The lower die and the upper die constitute a mold apparatus. The lower mold may be attached to the lower platen via a rotary table. The toggle support is disposed below the lower platen and moves up and down together with the upper platen. The toggle mechanism is disposed between the toggle support and the lower platen. The tie bar is parallel to the vertical direction, passes through the lower platen, and connects the upper platen and the toggle support. The number of tie bars is usually three. The number of tie bars is not particularly limited.

DESCRIPTION OF SYMBOLS 10 Clamping apparatus 12 Fixed platen 13 Movable platen 16 Tie bar 22 Axial force detector 23 Temperature controller 24 Temperature detector 30 Mold apparatus 32 Fixed mold 33 Movable mold 70 Operation apparatus 80 Display apparatus 82 Axial force balance display part 83 Horizontal axial force balance display unit 83a Set value display unit 83b Actual value display unit 84 Vertical axial force balance display unit 84a Set value display unit 84b Actual value display unit 90 Controller 101 Axial force setting unit 102 Axial force measurement unit 103 Non-interference calculation unit 104 Temperature setting unit 105 Temperature measurement unit 106 Temperature control command unit 107 Axial force estimation unit 108 Axial force calculation unit 109 Calculation correction unit

Claims (9)

Multiple tie bars that extend according to the clamping force,
A controller for controlling the axial force of the tie bar,
The controller is an injection molding machine that calculates a set value of an operation amount for changing the axial force based on a set value of a balance of the axial force.   2. The injection molding machine according to claim 1, wherein the controller calculates a set value of the operation amount based on an influence of the change in setting of the operation amount on the balance of the axial force.   The said controller acquires the track record value of the said axial force balance, and calculates the set value of the said operation amount based on the set value of the balance of the said axial force and its track record value. Injection molding machine.   4. The controller according to claim 1, wherein the controller acquires an estimated value of the axial force balance, and calculates a set value of the operation amount based on the set value of the axial force balance and the estimated value. The injection molding machine according to item 1.   5. The injection molding machine according to claim 1, wherein the controller calculates a set value of the operation amount based on a set value of the balance of the axial force in the horizontal direction.   6. The injection molding machine according to claim 1, wherein the controller calculates a set value of the operation amount based on a set value of a balance of the axial force in a vertical direction.   The injection molding machine according to claim 1, wherein the controller uses the difference in the axial force as the balance of the axial force.   The injection molding machine according to claim 7, wherein the controller represents the difference in the axial force as a ratio with respect to an average of the axial force.   9. The controller according to claim 1, wherein the controller uses at least one of a temperature of the tie bar, a length of the tie bar, and power supplied to a heater that heats the tie bar as the operation amount. Injection molding machine.

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