JP2020146847A - Injection molding machine and mold thickness calculation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection molding machine capable of an automatic tightening operation capable of accurately calculating a mold thickness and a mold thickness calculation method used in an injection molding machine. An injection molding machine 1 is provided in a movable mold 82, and is a distance sensor 18 as a timing detection sensor used for detecting a timing for acquiring a movable die plate position Lm2, which is a parameter for calculating a mold thickness Tk. have. The distance sensor 18 measures the distance D between the mold base 83 of the movable mold 82 and the intermediate plate 84. [Selection diagram] Fig. 4

Description

The present invention relates to an injection molding machine and a mold thickness calculation method used in an injection molding machine.

As shown in FIG. 7, the injection molding machine is provided with a tailstock 11, a movable die plate 12 to which the movable mold 82 is attached, and a fixed die plate 13 to which the fixed mold 86 is attached side by side in one direction. ing. The tailstock 11 and the movable die plate 12 are connected by a toggle link mechanism 14. The tailstock 11 and the fixed die plate 13 are connected by a plurality of tie bars (not shown in FIG. 7).

The injection molding machine can be combined with the movable mold 82 by adjusting the position of the tailstock 11 according to the dimensions of the movable mold 82 and the fixed mold 86 in the mold opening / closing direction (hereinafter, simply referred to as “mold thickness”). A predetermined mold clamping force is generated on the fixed mold 86. In the injection molding machine, when the toggle link mechanism 14 is extended, the movable die plate 12 advances toward the fixed die plate 13, and the movable mold 82 and the fixed mold 86 touch each other. When the toggle link mechanism 14 is further extended from there, the tie bar is elastically stretched, and the movable mold 82 and the fixed mold 86 are compacted with a predetermined mold clamping force by the elastic restoring force of the tie bar. It is important to accurately obtain the mold thickness in order to generate a predetermined mold clamping force.

For example, when the mold is replaced, the position of the tail stock 11 with respect to the fixed die plate 13 is adjusted so as to acquire the mold thickness of the mold and generate a predetermined mold clamping force. The operation of automatically adjusting the position of the tail stock 11 is called "automatic tightening operation".

In the automatic tightening operation, first, as shown in FIG. 7A, the tailstock 11 is advanced with the toggle link mechanism 14 fully extended. Generally, a motor having a relatively small output is used as the mold thickness adjusting motor for advancing the tailstock 11. Therefore, as shown in FIG. 7B, when the advance of the tailstock 11 is stopped, it can be determined that the movable mold 82 and the fixed mold 86 have touched each other. At this time, the position of the tail stock 11 with respect to the fixed die plate 13 (tail stock position Lt1) and the position of the movable die plate 12 with respect to the tail stock 11 (movable die plate position Lm1) are acquired.

Next, the mold thickness Tk (Tk = Lt1-Lm1) is calculated using the tail stock position Lt1 and the movable die plate position Lm1. The value obtained by subtracting the tightening distance M according to the elongation amount of the tie bar that generates a predetermined mold clamping force from the mold thickness Tk is calculated as the molding machine mold thickness Ts (Ts = Tk−M). As shown in FIG. 7C, the tailstock 11 is moved to the tailstock position Lt2 (Lt2 = Ts + Lm1) in which the movable die plate position Lm1 is added to the molding machine mold thickness Ts calculated using the mold thickness Tk.

Then, as shown in FIG. 7D, the toggle link mechanism 14 is fully extended with the tailstock 11 at the tailstock position Lt2. As a result, the tailstock 11 retracts from the tailstock position Lt2 by the amount by which the tie bar is extended (tightening distance M), so that a predetermined mold clamping force is generated in the movable mold 82 and the fixed mold 86. ..

In injection molding machines, spring-loaded dies for compression molding may be used. When such a spring-loaded mold is used, as described above, the mold thickness adjusting motor has a relatively small output, so that the spring may not be compressed. Therefore, in the above method, the mold thickness (that is, the apparent mold thickness) in the extended state of the spring is obtained, and the mold thickness cannot be obtained accurately. Then, Patent Document 1 discloses an adjustment method corresponding to such a spring-loaded mold. In the method of Patent Document 1, the position of the tail stock corresponding to the mold is set from the input device, and the tail stock is moved toward the fixed die plate. The position of the tailstock when the tailstock becomes immobile is detected, and it is determined whether or not the difference between the detected position value and the set value is equal to or greater than a predetermined value. Then, when it is determined that the difference is equal to or greater than a predetermined value, the toggle link mechanism is folded, the tailstock is moved again, and the toggle link mechanism is operated to touch the movable mold with the fixed mold.

JP-A-2007-1049

However, in the injection molding machine of Patent Document 1, it is necessary to set the position of the tail stock corresponding to the mold in advance by the input device. Therefore, it is necessary to know the position of the tail stock corresponding to the mold in advance, and simply by attaching the mold, the mold thickness is acquired and the position of the tail stock is automatically adjusted. Cannot tighten. In addition, when the output of the mold thickness adjustment motor for advancing the tailstock is large, the tie bar stretches when the tailstock is further advanced after the movable mold and the fixed mold touch, resulting in mold thickness. May not be obtained accurately.

Therefore, an object of the present invention is to provide an injection molding machine capable of an automatic tightening operation capable of accurately calculating a mold thickness and a mold thickness calculation method used in an injection molding machine.

In order to achieve the above object, the injection molding machine according to one aspect of the present invention includes a tail stock, a movable die plate to which a movable mold is attached, a fixed die plate to which a fixed mold is attached, and the tail stock. A toggle link mechanism for connecting the movable die plate, a plurality of tie bars for connecting the tail stock and the fixed die plate, and a die thickness adjusting drive unit for advancing and retreating the tail stock with respect to the fixed die plate. The movable mold has a mold clamping drive unit for extending and bending the toggle link mechanism, and a control unit for controlling the mold thickness adjusting drive unit and the mold clamping drive unit and calculating the mold thickness. Alternatively, it is characterized by having a timing detection sensor provided in the fixed mold and used for detecting the timing for acquiring the parameter for calculating the mold thickness.

In the present invention, the movable mold or the fixed mold is a spring-loaded mold having a mold base, an intermediate plate, and a spring arranged between the mold base and the intermediate plate, and is used for timing detection. The sensor is a distance sensor that measures the distance between the mold base and the intermediate plate, and is measured by the timing detection sensor when the control unit extends the toggle link mechanism by the mold clamping drive unit. It is preferable to acquire the position of the movable die plate with respect to the tailstock as the calculation parameter at the timing when the change of the distance is stopped.

In the present invention, one of the movable mold and the fixed mold is a spring-loaded mold having a spring arranged between the movable mold and the fixed mold, and the timing detection sensor is the movable mold and the fixed mold. It is a distance sensor that measures the distance to and from, and at the timing when the change in the distance measured by the timing detection sensor stops when the control unit extends the toggle link mechanism by the mold clamping drive unit. It is preferable to acquire the position of the movable die plate with respect to the tail stock as the calculation parameter.

In order to achieve the above object, the mold thickness calculation method used in the injection molding machine according to another aspect of the present invention includes a tail stock, a movable die plate to which a movable mold is attached, and a fixed mold. It has a fixed die plate, a toggle link mechanism for connecting the tail stock and the movable die plate, and a plurality of tie bars for connecting the tail stock and the fixed die plate, and has the movable mold or the movable mold. A mold thickness calculation method used in an injection molding machine in which a fixed mold is a spring-loaded mold having a mold base, an intermediate plate, and a spring arranged between the mold base and the intermediate plate. The position of the movable die plate with respect to the tail stock in a state where the toggle link mechanism is fully extended, and the position of the tail stock with respect to the fixed die plate when the movable mold and the fixed mold touch in the state. And, the apparent mold thickness is calculated, and the molding machine mold thickness is calculated using the apparent mold thickness and the tightening distance according to the elongation amount of the tie bar that generates a predetermined mold clamping force. Then, when the tailstock is moved to the tailstock position corresponding to the apparent mold thickness and the toggle link mechanism is extended, the change in the distance between the mold base and the intermediate plate stops. The position of the movable die plate with respect to the tail stock was acquired, the mold thickness of the molding machine, the position of the movable die plate with respect to the tail stock with the toggle link mechanism fully extended, and the acquisition at the timing. It is characterized in that the actual mold thickness is calculated using the position of the movable die plate with respect to the tail stock.

In order to achieve the above object, the mold thickness calculation method used in the injection molding machine according to another aspect of the present invention includes a tail stock, a movable die plate to which a movable mold is attached, and a fixed mold. It has a fixed die plate, a toggle link mechanism for connecting the tail stock and the movable die plate, and a plurality of tie bars for connecting the tail stock and the fixed die plate, and has the movable mold and the movable mold. A mold thickness calculation method used in an injection molding machine in which one of the fixed molds is a spring-loaded mold having a spring arranged between the fixed mold and the other, and the tail in a state where the toggle link mechanism is fully extended. Using the position of the movable die plate with respect to the stock and the position of the tailstock with respect to the fixed die plate when one of the movable mold and the fixed mold touches the spring in the state. The apparent mold thickness is calculated, and the molding machine mold thickness is calculated using the apparent mold thickness and the elongation amount of the tie bar that generates a predetermined mold clamping force, and the tail corresponding to the apparent mold thickness is calculated. The position of the movable die plate with respect to the tail stock at the timing when the change in the distance between the movable mold and the fixed mold stops while the tail stock is moved to the stock position and the toggle link mechanism is extended. The thickness of the molding machine, the position of the movable die plate with respect to the tail stock in a state where the toggle link mechanism is fully extended, and the position of the movable die plate with respect to the tail stock acquired at the timing. , Is used to calculate the actual mold thickness.

According to the present invention, it has a timing detection sensor provided in a movable mold or a fixed mold and used for detecting the timing of acquiring a parameter for calculating the mold thickness. From this, by acquiring the calculation parameters used for calculating the mold thickness at an appropriate timing, the calculation parameters can be acquired with high accuracy. Therefore, the mold thickness can be calculated accurately, and the automatic tightening operation can be executed using the calculated mold thickness.

It is a front view of the injection molding machine which concerns on one Embodiment of this invention. It is a functional block diagram of the injection molding machine of FIG. It is sectional drawing of the movable die (the die with a spring) attached to the movable die plate of the injection molding machine of FIG. It is a flowchart which shows an example of the automatic tightening operation in the injection molding machine of FIG. It is a figure explaining the automatic tightening operation in the injection molding machine of FIG. 1 (No. 1). It is a figure explaining the automatic tightening operation in the injection molding machine of FIG. 1 (No. 2). It is a figure explaining the conventional automatic tightening operation.

Hereinafter, the injection molding machine according to the embodiment of the present invention will be described with reference to FIGS. 1 to 6. This injection molding machine is used for compression molding in which a relatively high pressure is applied to the resin material in the cavity by reducing the volume of the cavity of the mold.

FIG. 1 is a front view of an injection molding machine according to an embodiment of the present invention. FIG. 2 is a functional block diagram of the injection molding machine of FIG. FIG. 3 is a cross-sectional view of a movable mold (spring-loaded mold) attached to the movable die plate of the injection molding machine of FIG. FIG. 3A shows a mold open state. FIG. 3B shows a state in which the movable mold and the fixed mold are touched (apparent mold thickness Ta). FIG. 3C shows a state in which the fixed mold and the movable mold having the minimum dimension in the mold opening / closing direction are closed (actual mold thickness Tk). FIG. 4 is a flowchart showing an example of the automatic tightening operation in the injection molding machine of FIG. 5 and 6 are views for explaining the automatic tightening operation in the injection molding machine of FIG. 1. FIG. 5A schematically shows how the tailstock is advanced in order to touch the movable mold and the fixed mold. FIG. 5B schematically shows a state in which the movable mold and the fixed mold are touched by advancing the tail stock, following FIG. 5A. FIG. 5C schematically shows a state in which the tailstock is moved to the tailstock position according to the apparent mold thickness. FIG. 5 (d) schematically shows a state in which the toggle link mechanism is fully extended from the state of FIG. 5 (c). FIG. 6A schematically shows how the toggle link mechanism is extended in order to touch the movable mold and the fixed mold when the tail stock is located at the tail stock position according to the apparent mold thickness. FIG. 6B schematically shows a state in which the movable mold and the fixed mold are touched by extending the toggle link mechanism, following FIG. 6A. FIG. 6C shows a state in which the toggle link mechanism is further extended following FIG. 6B, and the fixed mold and the movable mold having the minimum dimension in the mold opening / closing direction are closed. Is schematically shown. FIG. 6D schematically shows a state in which the toggle link mechanism is fully extended, following FIG. 6C.

As shown in FIGS. 1 and 2, the injection molding machine 1 includes a mold clamping unit 10, a distance sensor 18, an injection unit 20, and a control unit 30.

The mold clamping unit 10 is provided on the base 5. The mold clamping unit 10 has a tail stock 11, a movable die plate 12, and a fixed die plate 13. The tailstock 11 and the movable die plate 12 are provided so as to be able to advance and retreat with respect to the fixed die plate 13. The fixed die plate 13 is fixedly provided on the base 5. A movable mold 82 is attached to the movable die plate 12. A fixed mold 86 is attached to the fixed die plate 13. The tailstock 11, the movable die plate 12, and the fixed die plate 13 are arranged side by side in the mold opening / closing direction (left-right direction in FIG. 1) for opening and closing the movable mold 82 and the fixed mold 86. The tailstock 11 and the movable die plate 12 are connected by a toggle link mechanism 14. The tailstock 11 and the fixed die plate 13 are connected by a plurality of tie bars 15.

Further, the mold clamping unit 10 has a mold thickness adjusting drive unit 16 and a mold clamping drive unit 17. The mold thickness adjusting drive unit 16 is composed of, for example, an electric servomotor and a gear mechanism. The mold thickness adjusting drive unit 16 adjusts the position Lt of the tail stock 11 with respect to the fixed die plate 13. The mold clamping drive unit 17 is composed of, for example, an electric servomotor and a ball screw mechanism. The mold clamping drive unit 17 adjusts the position Lm of the movable die plate 12 with respect to the tailstock 11 by extending and bending the toggle link mechanism 14. When the toggle link mechanism 14 is extended, the movable die plate 12 moves forward, and the movable mold 82 and the fixed mold 86 touch each other. Further, when the toggle link mechanism 14 is fully extended, the tie bar 15 is elastically stretched, and the mold clamping unit 10 clamps the movable mold 82 and the fixed mold 86 with a predetermined mold clamping force by the elastic restoring force of the tie bar 15. To do. Further, when the toggle link mechanism 14 is retracted, the movable die plate 12 retracts, and the movable mold 82 and the fixed mold 86 are separated (mold open). The mold thickness adjusting drive unit 16 and the mold clamping drive unit 17 are controlled by a control signal from the control unit 30. The control unit 30 detects the position Lt of the tail stock 11 based on the control amount (rotation amount of the electric servomotor, etc.) of the mold thickness adjustment drive unit 16. Further, the control unit 30 detects the position Lm of the movable die plate based on the control amount (rotation amount of the electric servomotor, etc.) of the mold clamping drive unit 17. A sensor that detects the position Lt of the tail stock 11 and the position Lm of the movable die plate 12 may be provided.

Here, the movable mold 82 and the fixed mold 86 to be molded by the mold clamping unit 10 will be described with reference to FIG. The movable mold 82 and the fixed mold 86 are arranged so as to face each other by being attached to the movable die plate 12 and the fixed die plate 13, respectively.

The movable mold 82 is a spring-loaded mold for compression molding. The movable mold 82 has a mold base 83, an annular intermediate plate 84, and a spring 85. The mold base 83 is provided with a convex portion 83a protruding toward the fixed mold 86 side. The convex portion 83a is fitted and inserted inside the intermediate plate 84. The intermediate plate 84 can move in the mold opening / closing direction with respect to the mold base 83 with the convex portion 83a inserted inside. A coiled spring 85 is arranged between the mold base 83 and the intermediate plate 84. The force required to compress the spring 85 is greater than the force with which the mold thickness adjusting drive unit 16 advances the tailstock 11. The cavity 88 is formed by the convex portion 83a of the mold base 83, the intermediate plate 84, and the fixed mold 86. The fixed mold 86 is provided with a resin flow path 89 leading to the cavity 88.

The movable mold 82 is provided with a distance sensor 18 that measures a distance D (hereinafter, simply referred to as “distance D”) between the mold base 83 and the intermediate plate 84. The distance sensor 18 is composed of, for example, a linear gauge using light or magnetism. In the present embodiment, as the distance D, a value obtained by offsetting the actual distance between the mold base 83 and the intermediate plate 84 according to the mounting position of the distance sensor 18 and the like is used. That is, the distance sensor 18 outputs a value obtained by adding an offset value (for example, 2 mm) to the actual distance between the mold base 83 and the intermediate plate 84 as the distance D. For example, when the mold base 83 and the intermediate plate 84 touch and the dimension of the movable mold 82 in the mold opening / closing direction is minimized, the actual distance between the mold base 83 and the intermediate plate 84 becomes 0. When the distance sensor 18 outputs a signal indicating 2 mm as the distance D.

In the present embodiment, the distance D measured by the distance sensor 18 is 3 mm in the mold open state shown in FIG. 3A. In this state, the spring 85 remains stretched.

In the state shown in FIG. 3B, that is, in the state where the intermediate plate 84 of the movable mold 82 and the fixed mold 86 are in contact with each other, the distance D measured by the distance sensor 18 is 3 mm. In this state, although the intermediate plate 84 of the movable mold 82 and the fixed mold 86 are in contact with each other, the spring 85 is not compressed and remains stretched, and is intermediate with the mold base 83 of the movable mold 82. It is separated from the plate 84. At this time, the dimensions of the movable mold 82 and the fixed mold 86 in the opening / closing direction are referred to as the apparent mold thickness Ta.

In the state shown in FIG. 3C, that is, in the state where the fixed mold 86 and the movable mold 82 having the smallest dimension in the mold opening / closing direction are closed, the distance D measured by the distance sensor 18 is 2 mm. Become. In this state, the intermediate plate 84 of the movable mold 82 and the fixed mold 86 are in contact with each other, and the spring 85 is compressed so that the mold base 83 of the movable mold 82 and the intermediate plate 84 are in contact with each other. .. As a result, the volume of the cavity 88 becomes smaller than that in the state shown in FIG. 3B, and the cavity shape corresponds to the molded product. The dimensions of the movable mold 82 and the fixed mold 86 in the mold opening / closing direction at this time are referred to as the actual mold thickness Tk with respect to the apparent mold thickness Ta. In the present embodiment, the maximum movement amount of the intermediate plate 84 is 1 mm, and the apparent mold thickness Ta is 1 mm larger than the actual mold thickness Tk.

The fixed mold 86 is a normal mold without a spring. Instead of the movable mold 82, the fixed mold 86 may be used as a spring-loaded mold for compression molding.

The injection unit 20 includes an injection cylinder 21, a nozzle 22 provided at the tip of the injection cylinder 21, a heating device 23 for heating the injection cylinder 21, and a screw 24 housed in the injection cylinder 21 so as to be rotatable and retractable. have. Further, the injection unit 20 has a screw drive unit 25 that rotates and advances the screw 24 in the injection cylinder 21. The heating device 23 and the screw drive unit 25 are controlled by a control signal from the control unit 30.

The control unit 30 controls the operation of the entire injection molding machine 1. The control unit 30 includes, for example, a microcomputer for an embedded device having a central processing unit (CPU), a memory, various input / output interfaces, and the like. As shown in FIG. 2, the control unit 30 is connected to the mold thickness adjusting drive unit 16, the mold clamping drive unit 17, the distance sensor 18, the heating device 23, and the screw drive unit 25 so as to be able to transmit and receive signals. The control unit 30 controls each drive unit of the injection molding machine 1 in various operations such as a molding operation of a molded product and an automatic tightening operation. Information about various operations is stored in the memory of the control unit 30. As one of these information, the mold clamping force information in which the mold clamping force and the tightening distance M corresponding to the elongation amount of the tie bar 15 for generating the mold clamping force are associated with each other is stored in the memory.

Next, an example of the operation (automatic tightening operation) in the injection molding machine 1 of the present embodiment will be described with reference to FIGS. 4 to 6. In the automatic tightening operation, the actual mold thickness Tk of the movable mold 82 and the fixed mold 86 is calculated, and the position Lt of the tail stock 11 is automatically adjusted so as to generate a predetermined mold tightening force. The actual mold thickness Tk is, for example, 500 mm.

First, the control unit 30 of the injection molding machine 1 calculates the apparent mold thickness Ta (S110).

Specifically, in the mold open state shown in FIG. 5A, the control unit 30 controls the mold clamping drive unit 17 to bring the toggle link mechanism 14 into a fully extended state. Then, the control unit 30 controls the mold thickness adjustment drive unit 16 to advance the tail stock 11. The advance of the tail stock 11 is continued until the change of the position Lt of the tail stock 11 stops.

When the change in the position Lt of the tailstock 11 stops, the control unit 30 determines that the intermediate plate 84 of the movable mold 82 and the fixed mold 86 touch each other as shown in FIG. 5B, and determines that the mold thickness The advance of the tail stock 11 by the adjustment drive unit 16 is stopped. The control unit 30 calculates the apparent mold thickness Ta (Ta = Lt1-Lm1) by subtracting the movable die plate position Lm1 in the fully extended state of the toggle link mechanism 14 from the tailstock position Lt1 at this time. For example, if the tail stock position Lt1 is 3001 mm and the movable die plate position Lm1 is 2500 mm, the apparent mold thickness Ta is 501 mm. Then, the control unit 30 controls the mold clamping drive unit 17 to contract the toggle link mechanism 14.

Next, the control unit 30 calculates the molding machine mold thickness Ts (S120).

Specifically, the control unit 30 reads out from the memory the tightening distance M according to the amount of elongation of the tie bar 15 for generating a predetermined mold clamping force. For example, the tightening distance M is 5 mm. The control unit 30 calculates the value obtained by subtracting the tightening distance M from the apparent mold thickness Ta as the molding machine mold thickness Ts (Ts = Ta−M). For example, if the apparent mold thickness Ta is 501 mm and the tightening distance M is 5 mm, the molding machine mold thickness Ts is 496 mm.

Next, the control unit 30 moves the tailstock 11 to a position corresponding to the apparent mold thickness Ta (S130).

Specifically, as shown in FIG. 5C, the control unit 30 controls the mold thickness adjusting drive unit 16 to obtain a movable die plate to the molding machine mold thickness Ts calculated using the apparent mold thickness Ta. The tailstock 11 is moved to the tailstock position Lt2 (Lt2 = Ts + Lm1) to which the position Lm1 is added. For example, if the molding machine mold thickness Ts is 496 mm and the movable die plate position Lm1 is 2500 mm, the tail stock position Lt2 is 2996 mm.

Then, as shown in FIG. 5D, the control unit 30 controls the mold clamping drive unit 17 to extend the toggle link mechanism 14 in a state where the tail stock 11 is at the tail stock position Lt2. At this point, since the mold is compacted with respect to the apparent mold thickness Ta, the position Lt of the tail stock 11 is the position where the tightening distance M is added to the tail stock position Lt 2 or before the position (closer to the fixed die plate). ) (Lt ≦ Lt2 + M). Therefore, the tie bar 15 may not be sufficiently stretched and a predetermined mold clamping force may not be generated. Then, the control unit 30 controls the mold clamping drive unit 17 to contract the toggle link mechanism 14.

Next, the control unit 30 calculates the actual mold thickness Tk (S140).

Specifically, as shown in FIG. 6A, the control unit 30 controls the mold clamping drive unit 17 to gradually extend the toggle link mechanism 14 to advance the movable die plate 12. At this time, the distance D is, for example, 3 mm. The advance of the movable die plate 12 is continued after the change of the distance D measured by the distance sensor 18 starts and then stops.

The toggle link mechanism 14 advances the movable die plate 12 with sufficient force to compress the spring 85. Therefore, as shown in FIG. 6B, the movable die plate 12 continues to move forward even if the intermediate plate 84 of the movable mold 82 and the fixed mold 86 touch each other. When the intermediate plate 84 and the fixed mold 86 touch each other, the distance D starts to change. Then, when the change of the distance D is stopped, the control unit 30 contracts the spring 85 and the mold base 83 of the movable mold 82 and the intermediate plate 84 touch each other, and the movable mold 30 touches the movable mold 82 as shown in FIG. 6 (c). It is determined that the dimension of the mold 82 in the mold opening / closing direction is minimized, and the movable die plate position Lm2 at this time is detected (acquired). For example, the movable die plate position Lm2 is 2496 mm, and the distance D is 2 mm. The movable die plate position Lm2 is a calculation parameter used for calculating the mold thickness Tk. Further, the distance sensor 18 is a timing detection sensor used for detecting the timing of acquiring the movable die plate position Lm2. This timing is the timing at which the dimensions of the movable mold 82, which is a spring-loaded mold, in the mold opening / closing direction are minimized.

Then, the control unit 30 calculates the actual mold thickness Tk (Tk = Ts + (Lm1-Lm2)) by adding the value obtained by subtracting the movable die plate position Lm2 from the movable die plate position Lm1 to the molding machine mold thickness Ts. To do. For example, if the molding machine mold thickness Ts is 496 mm, the movable die plate position Lm1 is 2500 mm, and the movable die plate position Lm2 is 2496 mm, the mold thickness Tk is 500 mm. Then, the control unit 30 controls the mold clamping drive unit 17 to extend the toggle link mechanism 14 in a state where the tail stock 11 is at the tail stock position Lt2 as shown in FIG. 6D. Even at this point, since the mold is compacted with respect to the apparent mold thickness Ta, the predetermined mold clamping force does not occur. S110 to S140 are mold thickness calculation methods for calculating the actual mold thickness Tk.

Next, the control unit 30 recalculates the molding machine mold thickness Ts (S150).

Specifically, the control unit 30 calculates a value obtained by subtracting the tightening distance M from the calculated mold thickness Tk, and resets it as the molding machine mold thickness Ts (Ts = Tk−M). For example, if the mold thickness Tk is 500 mm and the tightening distance M is 5 mm, the molding machine mold thickness Ts is reset to 495 mm.

Next, the control unit 30 moves the tailstock 11 to a position corresponding to the actual mold thickness Tk (S160).

Specifically, the control unit 30 controls the mold thickness adjusting drive unit 16 and is movable when the toggle link mechanism 14 is fully extended to the molding machine mold thickness Ts recalculated using the actual mold thickness Tk. The tailstock 11 is moved to the tailstock position Lt3 (Lt3 = Ts + Lm1) to which the die plate position Lm1 is added. For example, if the molding machine mold thickness Ts is 495 mm and the movable die plate position Lm1 is 2500 mm, the tailstock position Lt3 is 2995 mm.

In this way, the actual mold thickness Tk can be calculated, and the tailstock 11 can be automatically moved to the tailstock position Lt3 that generates a predetermined mold clamping force with respect to the mold thickness Tk.

From the above, according to the injection molding machine 1 of the present embodiment, a timing detection sensor provided in the movable mold 82 and used for detecting the timing of acquiring the movable die plate position Lm2, which is a parameter for calculating the mold thickness Tk. It has a distance sensor 18 as a. From this, by acquiring the movable die plate position Lm2 used for calculating the mold thickness Tk at an appropriate timing, the movable die plate position Lm2 can be acquired with high accuracy. Therefore, the mold thickness Tk can be calculated accurately, and the automatic tightening operation can be executed using the calculated mold thickness Tk.

Further, the injection molding machine 1 has a position Lm of the movable die plate 12 (movable die plate position Lm1) with respect to the tailstock 11 in a state where the toggle link mechanism 14 is fully extended, and an intermediate plate 84 of the movable mold 82 in this state. The apparent mold thickness Ta is calculated using the position Lt of the tail stock 11 (tail stock position Lt1) with respect to the fixed die plate 13 when the fixed mold 86 and the fixed mold 86 are touched. The molding machine mold thickness Ts is calculated using the apparent mold thickness Ta and the tightening distance M according to the elongation amount of the tie bar 15 that generates a predetermined mold clamping force. The timing at which the change in the distance D between the mold base 83 and the intermediate plate 84 stops when the tail stock 11 is moved to the tail stock position Lt2 corresponding to the apparent mold thickness Ta and the toggle link mechanism 14 is gradually extended. Then, the position Lm of the movable die plate 12 with respect to the tail stock 11 (movable die plate position Lm2) is acquired. Then, the actual mold thickness Tk is calculated using the molding machine mold thickness Ts, the movable die plate position Lm1, and the movable die plate position Lm2. By doing so, the actual mold thickness Tk can be accurately obtained with a relatively simple operation.

In the injection molding machine 1 of the above-described embodiment, the movable mold 82 is a spring-loaded mold having a mold base 83, an annular intermediate plate 84, and a spring 85, but the present invention is limited to this. It's not a thing. For example, the movable mold (one mold) may be a spring-loaded mold having a spring that is in direct contact with the fixed mold (the other mold). This spring is arranged between the movable mold and the fixed mold. Then, when the movable mold advances toward the fixed mold, the spring first touches the fixed mold, and when the movable mold advances further, the spring contracts and the movable mold and the fixed mold touch. Instead of the movable mold, the fixed mold may be a spring-loaded mold. The injection molding machine 1 can accurately calculate the actual mold thickness even with such a spring-loaded mold.

Although the embodiments of the present invention have been described above, the present invention is not limited to these examples. The present invention also includes those skilled in the art with appropriate additions, deletions, and design changes to the above-described embodiments, and those appropriately combined with the features of the embodiments, unless contrary to the gist of the present invention. Is included in the range of.

1 ... Injection molding machine, 5 ... Base, 10 ... Mold clamping unit, 11 ... Tailstock, 12 ... Movable die plate, 13 ... Fixed die plate, 14 ... Toggle link mechanism, 15 ... Tie bar, 16 ... Mold thickness adjustment drive Unit, 17 ... Mold clamping drive unit, 18 ... Distance sensor, 20 ... Injection unit, 21 ... Injection cylinder, 22 ... Nozzle, 23 ... Heating device, 24 ... Screw, 25 ... Screw drive unit, 30 ... Control unit, 82 ... Movable mold, 83 ... Mold base, 83a ... Convex part, 84 ... Intermediate plate, 85 ... Spring, 86 ... Fixed mold, 88 ... Cavity, 89 ... Resin flow path, Tk ... Actual mold thickness, Ta ... Appearance Mold thickness, Lt ... position of tailstock with respect to fixed die plate, Lm ... position of movable die plate with respect to tailstock, M ... tightening distance (extension of tie bar), D ... distance between mold base and intermediate plate

Claims (5)

A tailstock, a movable die plate to which a movable mold is attached, a fixed die plate to which a fixed mold is attached, a toggle link mechanism for connecting the tailstock and the movable die plate, and the tailstock and the fixed die. A plurality of tie bars connecting the plates, a mold thickness adjusting drive unit for advancing and retreating the tailstock with respect to the fixed die plate, a mold clamping drive unit for extending and bending the toggle link mechanism, and the mold thickness adjustment. It has a drive unit and a control unit that controls the mold clamping drive unit and calculates the mold thickness.
An injection molding machine provided on the movable mold or the fixed mold and having a timing detection sensor used for detecting a timing for acquiring a parameter for calculating the mold thickness. The movable mold or the fixed mold is a spring-loaded mold having a mold base, an intermediate plate, and a spring arranged between the mold base and the intermediate plate.
The timing detection sensor is a distance sensor that measures the distance between the mold base and the intermediate plate.
When the change in the distance measured by the timing detection sensor stops when the control unit extends the toggle link mechanism by the mold clamping drive unit, the tailstock is used as a calculation parameter. The injection molding machine according to claim 1, wherein the position of the movable die plate is acquired. One of the movable mold and the fixed mold is a spring-loaded mold having a spring arranged between the movable mold and the fixed mold.
The timing detection sensor is a distance sensor that measures the distance between the movable mold and the fixed mold.
When the change in the distance measured by the timing detection sensor stops when the control unit extends the toggle link mechanism by the mold clamping drive unit, the tailstock is used as a calculation parameter. The injection molding machine according to claim 1, wherein the position of the movable die plate is acquired. A tailstock, a movable die plate to which a movable mold is attached, a fixed die plate to which a fixed mold is attached, a toggle link mechanism for connecting the tailstock and the movable die plate, and the tailstock and the fixed die. It has a plurality of tie bars that connect the plates, and the movable mold or the fixed mold has a mold base and an intermediate plate, and a spring arranged between the mold base and the intermediate plate. This is a mold thickness calculation method used in an injection molding machine that is a spring-loaded mold.
The position of the movable die plate with respect to the tail stock in a state where the toggle link mechanism is fully extended, and the position of the tail stock with respect to the fixed die plate when the movable mold and the fixed mold touch in the state. Calculate the apparent mold thickness using the position and
The molding machine mold thickness is calculated using the apparent mold thickness and the elongation amount of the tie bar that generates a predetermined mold clamping force.
The tail is moved to a tail stock position corresponding to the apparent mold thickness, and the tail stops changing the distance between the mold base and the intermediate plate while the toggle link mechanism is extended. Obtain the position of the movable die plate with respect to the stock,
Using the molding machine mold thickness, the position of the movable die plate with respect to the tail stock in a state where the toggle link mechanism is fully extended, and the position of the movable die plate with respect to the tail stock acquired at the timing. A mold thickness calculation method characterized in that an actual mold thickness is calculated. A tailstock, a movable die plate to which a movable mold is attached, a fixed die plate to which a fixed mold is attached, a toggle link mechanism for connecting the tailstock and the movable die plate, and the tailstock and the fixed die. Used in an injection molding machine that has a plurality of tie bars that connect the plates, and one of the movable mold and the fixed mold is a spring-loaded mold having a spring arranged between the movable mold and the other. It is a mold thickness calculation method
The position of the movable die plate with respect to the tailstock in a state where the toggle link mechanism is fully extended, and the fixing when one of the movable mold and the fixed mold touches the spring and the other in the state. The position of the tailstock with respect to the die plate and the apparent mold thickness are calculated using.
The molding machine mold thickness is calculated using the apparent mold thickness and the elongation amount of the tie bar that causes a predetermined mold clamping force.
When the tailstock is moved to the tailstock position corresponding to the apparent mold thickness and the change in the distance between the movable mold and the fixed mold stops while the toggle link mechanism is extended, the said. Obtain the position of the movable die plate with respect to the tailstock,
Using the molding machine mold thickness, the position of the movable die plate with respect to the tail stock in a state where the toggle link mechanism is fully extended, and the position of the movable die plate with respect to the tail stock acquired at the timing. A mold thickness calculation method characterized in that an actual mold thickness is calculated.

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