TW201726353A - Injection molding machine capable of suppressing the discontinuity of temperature control of the tie bar and improving the accuracy of temperature control of the tie bar - Google Patents

Abstract

An object of the invention is to provide an injection molding machine capable of suppressing the discontinuity of temperature control of the tie bar and improving the accuracy of temperature control of the tie bar. An injection molding machine according to a solution of the invention includes a plurality of tie bars extending based upon clamping force; a heater for heating the tie bars; and a controller controlling the heater. The controller adjusts the temperature of the heated portion of the tie bars heated by the heater, adjusts the balance of the axial force of the tie bars so that the base temperature of the heated portion used in the adjustment of the balance is set as the temperature that is higher than the stable temperature of the heated portion when the heater is not in heating.

Description

Injection molding machine

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 the mold device. The mold clamping device has a plurality of root rods that extend in accordance with the mold clamping force (for example, refer to Patent Document 1). The clamping force is dispersed and applied to the plurality of tie rods so that the tie bars extend. The force that hinders the extension of the tie rod is referred to as an axial force.

When there is a difference in the effective length of the plurality of root rods, a difference in axial force is generated between the tie rod having a shorter effective length and the tie rod having a longer effective length. Here, the effective length of the tie rod refers to the interval between the members joined by the tie rods, for example, in a state where the mold clamping force is not applied.

The effective length of the tie rod varies depending on the temperature of the tie rod. The higher the temperature of the tie rod, the longer the effective length of the tie rod. The effective length of the tie rod can be adjusted by adjusting the temperature of the tie rod, and the balance of the axial force can be adjusted.

In the injection molding machine described in Patent Document 1, when the effective length of the tie rod is adjusted, both the belt heater that heats the tie rod and the water jacket that cools the tie rod are used. Heating based on belt heaters and based on water The amount of cooling of the jacket is used as the manipulated amount of temperature for manipulating the tie rod.

(previous technical literature) (Patent Literature)

Patent Document 1: Japanese Laid-Open Patent Publication No. 2008-114513

Conventionally, the type of the manipulation amount of the temperature of the manipulation lever is switched, and the mechanism by which the manipulation amount is influenced by the temperature may be switched. As a result, the temperature control of the tie bar may become discontinuous, and the accuracy of the temperature control of the tie bar may become low.

The present invention has been made in view of the above problems, and a main object thereof is to provide an injection molding machine capable of suppressing discontinuity in temperature control of a tie bar and improving the accuracy of temperature control of the tie bar.

In order to solve the above problems, an injection molding machine is provided according to an aspect of the present invention, comprising: a plurality of root rods extending according to a mold clamping force; a heater for heating the tie rod; and a controller Controlling the heater, the controller adjusting a temperature of the heating portion of the tie rod heated by the heater, adjusting a balance of axial forces of the plurality of tie rods, and using the heating portion in the balance adjustment The reference temperature is It is set to be higher than a stable temperature of the heating unit based on the non-heating of the heater.

According to an aspect of the present invention, an injection molding machine capable of suppressing discontinuity in temperature control of a tie bar and improving the accuracy of temperature control of the tie bar is provided.

10‧‧‧Molding device

12‧‧‧Fixed platen

13‧‧‧Active platen

16‧‧‧ tied

25‧‧‧heater

26‧‧‧heat transfer limiter

27‧‧‧ Temperature detector

28‧‧‧Axial force detector

30‧‧‧Molding device

32‧‧‧Fixed mode

33‧‧‧ activity model

90‧‧‧ Controller

Fig. 1 is a view showing a state at the time of completion of mold opening of an injection molding machine according to an embodiment.

Fig. 2 is a view showing a state at the time of mold clamping of the injection molding machine of the embodiment.

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 pressure plate as seen from the movable platen side.

In the following, the embodiments of the present invention are described with reference to the drawings, and the same or corresponding components are designated by the same or corresponding elements, and the description thereof will be omitted.

Fig. 1 is a view showing a state at the time of completion of mold opening by an injection molding machine according to an embodiment. Fig. 2 is a view showing a state at the time of mold clamping by an injection molding machine according to an embodiment. The injection molding machine has 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 has a CPU (Central Processing Unit) 91 and a memory medium 92 such as a memory. The controller 90 causes the CPU 91 to execute a program stored in the memory medium 92, thereby controlling the mold clamping device 10, the operation device 70, the display device 80, and the like.

The controller 90 is connected to the operating device 70 and the display device 80. The operation device 70 and the display device 80 are constituted by, for example, a touch panel, and can be integrated. The operation device 70 receives an input operation based on 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 the input operation in the operation device 70 under the control of the controller 90. The operation screen is used in the setting of the injection molding machine or the like. Prepare a plurality of operation screens, switch display or overlap display. The user operates the operation device 70 while viewing the operation screen displayed on the display device 80, thereby setting the injection molding machine and the like.

Further, although the operation device 70 and the display device 80 of the present embodiment are integrated, they may be provided separately. Further, a plurality of operating devices 70 can be provided.

The mold clamping device 10 performs mold closing, mold clamping, and mold opening of the mold device 30. The mold clamping device 10 has a fixed platen 12, a movable platen 13, a rear platen 15, a tie rod 16, a toggle mechanism 20, and a mold clamping motor 21. In the following, the moving direction of the movable platen 13 (the right direction in the first drawing and the second drawing) at the time of mold closing is taken as the front, and the moving direction of the movable platen 13 at the time of mold opening (the first drawing and the second drawing) The left direction) will be described as the rear.

The fixed platen 12 is fixed to the frame Fr. A fixed mold 32 is attached to the opposite side of the fixed platen 12 from the movable platen 13.

The movable platen 13 is freely 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. The movable mold 33 is attached to the side of the movable platen 13 opposite to the fixed platen 12.

The movable platen 13 is advanced and retracted with respect to the fixed platen 12, thereby performing mold closing, mold clamping, and mold opening. The fixed mold 32 and the movable mold 33 constitute a mold device 30.

The rear pressure plate 15 is coupled to the fixed pressure plate 12 at intervals, and is movably placed on the frame Fr in the opening and closing mold direction. In addition, the rear platen 15 can be moved freely along the guides laid on the frame Fr. The guide of the rear platen 15 can be shared with the guide 17 of the movable platen 13.

Further, in the present embodiment, the fixed pressure plate 12 is fixed to the frame Fr, and the rear pressure plate 15 is movable in the opening and closing mold direction with respect to the frame Fr. However, the rear pressure plate 15 may be fixed to the frame Fr, and the fixed pressure plate 12 may be fixed to the frame Fr. The frame Fr moves freely in the direction of the opening and closing mold.

The tie rod 16 connects the fixed pressure plate 12 and the rear pressure plate 15 at intervals. A plurality of root rods 16 are used. Each tie rod 16 is parallel along the direction of the mold opening and closing and extends in accordance with the mold clamping force. Each tie rod 16 is formed of metal or the like.

The toggle mechanism 20 is disposed between the movable platen 13 and the rear platen 15. The toggle mechanism 20 is composed of a crosshead 20a, a plurality of links 20b, 20c, and the like. One link 20b is swingably attached to the movable platen 13, and the other link 20c is swingably attached to the rear platen 15. The links 20b and 20c are coupled to each other by a pin or the like. By the advance and retreat of the crosshead 20a, the plurality of links 20b, 20c are expanded and contracted, and the movable platen 13 advances and retracts relative to the rear platen 15.

The mold clamping motor 21 is attached to the rear platen 15, and the crosshead 20a is advanced and retracted, whereby the movable platen 13 is advanced and retracted. Between the mold clamping motor 21 and the crosshead 20a, a motion conversion mechanism that converts the rotational motion of the mold clamping motor 21 into a linear motion and transmits it to the crosshead 20a is provided. The motion conversion mechanism is constituted by, for example, a ball screw mechanism.

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

In the mold closing process, the mold clamping motor 21 is driven to advance the movable platen 13, whereby the movable mold 33 is brought into contact with the fixed mold 32.

In the mold clamping process, the mold clamping force is generated by further driving the mold clamping motor 21. When the mold is closed, a cavity space is formed between the movable mold 33 and the fixed mold 32, and the cavity space is filled with a liquid molding material. The molding material in the cavity space is hardened to become a molded article.

In the mold opening process, the mold clamping motor 21 is driven to retract the movable platen 13, thereby separating the movable mold 33 from the fixed mold 32.

Further, 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. Further, the mold clamping device 10 may have a linear motor used for opening and closing the mold, and has an electromagnet for clamping.

Fig. 3 is a view showing the positional relationship of the tie bars of the injection molding machine according to the embodiment, and the fixed platen is viewed from the side of the movable platen. The injection molding machine has four tie rods 16. When viewed from the direction of the opening and closing mold, the four tie bars 16 are vertically symmetrical about the horizontal line L1, and are arranged bilaterally symmetrically about the vertical line L2. It will be called the top side of the horizontal line L1. On the side, the lower side than the horizontal line L1 is referred to as the bottom side. Further, a side closer to the operation device 70 than the vertical line L2 is referred to as an operation side, and a side closer to the operation device 70 than the vertical line L2 is referred to as a reverse operation side.

The clamping force is dispersed and applied to the four tie bars 16 so that the tie bars 16 extend. The force that hinders the extension of each tie rod 16 is referred to as an axial force. When there is a difference in the effective lengths of the four tie bars 16, the difference in axial force is generated between the tie bars 16 having a shorter effective length and the tie bars 16 having a longer effective length. Here, the effective length of the tie rod 16 means the interval between the fixed platen 12 and the rear platen 15 joined by the tie rod 16, for example, in a state where the mold clamping force is not applied.

The balance of the axial forces can be adjusted by adjusting the effective length of the tie rod 16. The balance of the axial force is set such that the surface pressure of the fixed mold 32 and the movable mold 33 becomes a target distribution, for example, at the time of mold clamping. The target distribution may be any of a uniform distribution and an uneven distribution, and is set depending on the situation. Can reduce molding defects.

The effective length of the tie rod 16 varies depending on the temperature of the tie rod 16. The higher the temperature of the tie rod 16, the longer the effective length of the tie rod 16. The effective length of the tie rod 16 can be adjusted by adjusting the temperature of the tie rod 16, so that the balance of the axial force can be adjusted.

Then, as shown in Figs. 1 and 2, the heater 25, the heat transfer limiter 26, the temperature detector 27, the axial force detector 28, and the like are attached to the respective tie bars 16. The mold clamping device 10 includes a heater 25, a heat transfer limiter 26, a temperature detector 27, an axial force detector 28, and the like.

The heater 25 is for the tie rod 16 in order to adjust the effective length of the tie rod 16 Heat up. The range in which the heater 25 is heated is referred to as a heating portion of the tie rod 16. The heater 25 is constituted by, for example, an electric heater such as a heater. Further, the heater 25 is not limited to the electric heater, and may be constituted, for example, by a warm water jacket or the like.

The heat transfer limiter 26 limits heat transfer from the heating portion of the tie rod 16. The time until the temperature of the entire mold clamping device 10 is stabilized can be shortened, and the time until the balance of the axial force becomes stable can be shortened. Moreover, since the range of the heating part of the tie rod 16 can be managed, the amount of change in the effective length by the temperature change of the tie rod 16 can be managed with high precision, and the axial force can be adjusted with high precision.

The heat transfer limiter 26 can be disposed on both axial sides of the tie rod 16 with the heater 25 interposed therebetween. The time until the temperature of the entire mold clamping device 10 becomes stable can be further shortened, and the time until the balance of the axial force becomes stable can be further shortened. Moreover, the amount of change in the effective length based on the temperature change of the tie rod 16 can be managed with higher precision, and the axial force can be adjusted with higher precision.

The heat transfer limiter 26 is constituted, for example, by a water jacket. Further, the heat transfer limiter 26 is not limited to the water jacket, and may be constituted by, for example, a heat sink or the like. The cooling method of the heat sink may be any one of a forced air cooling method and a natural air cooling method of the heat sink.

The heat transfer limiter 26 is not intended to adjust the effective length of the tie rod 16, but is used for the purpose of managing the range of the heating portion of the tie rod 16. The effective length of the tie rod 16 is adjusted by the heater 25 and is not adjusted by the heat transfer limiter 26. Therefore, the heat transfer limiter 26 may not be mounted on the tie rod 16.

The temperature detector 27 detects the temperature of the heating portion of the tie rod 16. For example, the temperature detector 27 is disposed in the vicinity of the heater 25 and disposed between the plurality of heat transfer limiters 26.

The temperature detector 27 outputs the detection result to the controller 90. The controller 90 controls the heater 25 in accordance with the actual temperature and the set temperature detected by the temperature detector 27. For example, the controller 90 controls the heater 25 so that the actual temperature becomes the set temperature. The control may be any one of feedback control and feedforward control.

The axial force detector 28 detects the axial force of the tie rod 16 heated by the heater 25. The axial force detector 28 is, for example, a strain ritual, and the axial force of the tie rod 16 is detected by detecting the deformation of the tie rod 16.

Further, the axial force detector 28 of the above embodiment is a strain ceremony, but may be a piezoelectric type, a capacitive type, a hydraulic type, an electromagnetic type or the like.

The axial force detector 28 outputs the detection result to the controller 90. The controller 90 measures the balance of the axial forces of the plurality of root rods 16 by the axial force detector 28.

The axial force detector 28 is disposed on the opposite side of the heater 25 with reference to the heat transfer limiter 26. An axial force detector 28 is disposed outside the heating range based on the heater 25. The temperature rise of the axial force detector 28 can be suppressed, and the measurement error of the axial force detector 28 can be reduced.

As shown in FIGS. 1 and 2, the axial force detector 28 is disposed, for example, on the rear side of the heat transfer limiter 26, and the heat transfer limiter 26 is disposed on the rear side of the heater 25. In addition, the axial force detector 28 is assigned to the specific transmission The heat limiter 26 is further on the front side, and the heat transfer limiter 26 is disposed on the front side of the heater 25.

Further, the axial force detector 28 of the present embodiment is disposed on the opposite side of the heater 25 with respect to the heat transfer limiter 26, but may be disposed at a position overlapping the heat transfer limiter 26. Even in this case, the temperature rise of the axial force detector 28 can be suppressed, and the measurement error of the axial force detector 28 can be reduced.

The controller 90 adjusts the temperature of the heating portion of the tie rod 16 heated by the heater 25, and adjusts the balance of the axial forces of the plurality of root rods 16. The reference temperature T0 of the heating portion of the tie rod 16 used for the balance adjustment is set to be higher than the stable temperature TS of the heating portion of the tie rod 16 when the heater 25 is not heated.

The non-heating by the heater 25 means that, for example, when the heater 25 is an electric heater, when the supply of the electrode to the electric heater is stopped, and when the heater 25 is a warm water jacket, the supply of warm water to the hot water jacket is stopped.

In addition, the steady temperature TS is the temperature of the heating part of the tie rod 16 when the temperature of the whole mold clamping device 10 becomes stable when the heater 25 is not heated. Here, the settings of the devices other than the heater 25 (for example, the thermostat that adjusts the temperature of the mold device 30, the injection device that fills the mold device 30 with the liquid molding material, and the like) are the same.

The controller 90 measures, for example, the balance of the axial forces of the plurality of root rods 16 when the temperature of the heating portion of the tie rod 16 is the reference temperature T0. If the balance is within the allowable range, the controller 90 maintains the temperature of the heating portion of the tie rod 16 at the reference temperature T0. On the other hand, if the balance is outside the allowable range, the controller 90 increases or decreases the temperature of the heating portion of the tie rod 16 in accordance with the difference. The controller 90 then measures the balance of the axial forces of the plurality of root rods 16 again. Then, the temperature adjustment of the heating portion of the tie rod 16 and the measurement of the balance of the axial force can be repeated until the balance is suppressed within the allowable range.

According to the present embodiment, as described above, the reference temperature T0 of the heating portion of the tie rod 16 used for the balance adjustment is set to a temperature higher than the stable temperature TS. Thereby, it is possible to adjust both the temperature rise and the temperature decrease from the reference temperature T0 by only the amount of heating of the heater 25, and not to switch the type of the manipulation amount of the manipulation temperature, and also to switch the operation amount to the temperature. The mechanism of the impact. Thereby, the discontinuity of the temperature control of the tie rod 16 can be suppressed, and the precision of the temperature control of the tie rod 16 can be improved.

The temperature adjustment range of the heating portion of the tie rod 16 used for the balance adjustment is a temperature range higher than the stable temperature TS of the heating portion. Since the temperature of the tie rod 16 is adjusted only by the amount of heating of the heater 25, the kind of the manipulation amount of the manipulation temperature is not changed, and the mechanism of the influence of the operation amount on the temperature is not changed. Thereby, the discontinuity of the temperature control of the tie rod 16 can be further suppressed, and the precision of the temperature control of the tie rod 16 can be further improved.

The reference temperature T0 of the heating portion of the tie rod 16 used for the balance adjustment can be set to a temperature higher than the temperature around the heating portion by a predetermined value. Here, the temperature around the heating portion is, for example, the temperature of the surrounding atmosphere of the heating portion. Since the reference temperature T0 changes depending on the temperature change of the surrounding atmosphere of the heating unit, it is possible to adjust the balance corresponding to the temperature change of the surrounding atmosphere of the heating unit.

Further, the controller 90 of the present embodiment controls the heater 25 and does not control the heat transfer limiter 26, but may control the heat transfer limiter 26. The controller 90 controls the heat transfer limiter 26 to bring the temperature of the tie rod to a set temperature near the heat transfer limiter 26.

In the above, the embodiment of the injection molding machine has been described. However, the present invention is not limited to the above-described embodiments and the like, and various modifications and improvements can be made within the scope of the gist of the invention described in the claims.

For example, in the above embodiment, the heater 25, the heat transfer limiter 26, the temperature detector 27, the axial force detector 28, and the like are attached to all of the tie bars 16, but they may be attached only to a part of the tie bars 16. For example, in the case where the controller 90 adjusts the balance of the axial force in the vertical direction (hereinafter referred to as "vertical axial force balance") and the balance of the axial force in the horizontal direction, it is possible to The heater 25, the heat transfer limiter 26, and the temperature detector 27 are mounted in only three of the tie rods 16. Further, when the controller 90 adjusts only the vertical axial force balance, the heater 25, the heat transfer limiter 26, and the temperature detector 27 may be attached only to the tie bars 16 on one of the top side and the bottom side. Moreover, when the controller 90 adjusts only the vertical axial force balance, one of the two tie bars 16 on the top side and one of the two tie bars 16 on the bottom side can be respectively mounted with axial force detection. 28

Further, the mold clamping device 10 of the above-described embodiment has a horizontal type in which the opening and closing mold direction is horizontal, but may be a vertical type in which the opening and closing mold direction is in the vertical direction. The vertical mold clamping device has a lower pressing plate, an upper pressing plate, a toggle joint, a toggle mechanism, and a tie rod. Any one of the lower platen and the upper platen is used as a fixed platen, and the other one is used as a movable platen. Install the lower mold on the lower platen, and Install the mold on the upper platen. The mold device is constituted by the lower mold and the upper mold. The lower mold can be mounted to the lower platen via the turntable. The elbow seat is arranged below the lower platen. The toggle mechanism is disposed between the toggle seat and the lower platen. The tie rod is parallel to the vertical direction, passes through the lower pressure plate, and connects the upper pressure plate and the toggle seat. The number of tie rods is usually three. Further, the number of tie rods is not particularly limited.

10‧‧‧Molding device

12‧‧‧Fixed platen

13‧‧‧Active platen

15‧‧‧ rear platen

16‧‧‧ tied

17‧‧‧ Guides

20‧‧‧Toggle mechanism

20c‧‧‧ connecting rod

20a‧‧‧ crosshead

20b‧‧‧ Connecting rod

21‧‧‧Molded motor

25‧‧‧heater

26‧‧‧heat transfer limiter

27‧‧‧ Temperature detector

28‧‧‧Axial force detector

30‧‧‧Molding device

32‧‧‧Fixed mode

33‧‧‧ activity model

70‧‧‧Operator

80‧‧‧ display device

90‧‧‧ Controller

91‧‧‧CPU

92‧‧‧Memory Media

Fr‧‧ frame

Claims (3)

An injection molding machine comprising: a plurality of root rods extending according to a mold clamping force; a heater for heating the tie rod; and a controller for controlling the heater, wherein the controller adjusts the aforementioned heating by the heater The temperature of the heating portion of the tie rod adjusts the balance of the axial forces of the plurality of tie rods, and the reference temperature of the heating portion used in the adjustment of the balance is set to be higher than the aforementioned temperature during the non-heating of the heater The stable temperature of the heating section is higher. The injection molding machine according to the first aspect of the invention, wherein the temperature adjustment range of the heating unit used in the adjustment of the balance is a temperature range higher than the stable temperature of the heating unit. The injection molding machine according to the first or second aspect of the invention, wherein the reference temperature of the heating unit used in the adjustment of the balance is set to a temperature higher than a temperature around the heating unit by a predetermined value.