Control method for injection molding machines

Abstract

This enables efficient injection molding while meeting safety standards. [Solution] A control method for an injection molding machine 10 having a clamping device for clamping an upper mold 8 and a lower mold 7, comprising a rotary table 2 to which a plurality of lower molds are attached, and a movable platen 3 to which an upper mold is attached, and comprising a rear intrusion detection sensor 40 that detects intrusion from the molded product removal area K2 to the clamping area K1, a front intrusion detection sensor 50 that detects intrusion into the molded product removal area from the outside, and a clamping detection sensor 60 that detects when clamping has been performed, wherein when the clamping detection sensor detects that clamping has been performed, the rear intrusion detection sensor detects intrusion, and when the clamping detection sensor detects that clamping has not been performed, the system switches to detecting intrusion using the front intrusion detection sensor.

Description

Technical Field

[0001] The present invention relates to a control method for an injection molding machine.

Background Art

[0002] The injection molding machine described in Patent Document 1 has a rotary table held rotatably on a fixed plate, a plurality of fixed molds arranged at equal angles on the rotary table, and a movable mold movable up and down with respect to the fixed mold. The injection molding machine intermittently rotates the rotary table and sequentially performs injection filling on the mold placed at the injection position. This injection molding machine has a safety door that can be opened and closed on one side of the space where the movable mold moves up and down. When the safety door is opened, the movement of the movable mold in the mold closing direction is mechanically locked.

[0003] When a safety door is provided, each time an operator takes out a molded product from the mold, it is necessary to open and close the safety door, which makes the work complicated. Therefore, an opening that is always open to the outside may be provided on one side of the space where the movable mold moves up and down, and an intrusion detector (for example, a light curtain) that detects an object entering from the outside through the opening may be provided. When the intrusion detector detects the intrusion of an object during mold closing, the mold closing is interrupted. Therefore, it is possible to prevent a part of the operator's body from being sandwiched between a member that moves during mold closing (for example, a movable mold) and a member that does not move during mold closing (for example, a fixed mold).

[0004] Conventionally, the molded product has been taken out during the injection operation. However, with the enactment of JIS B 6711, when the light curtain on the operator side is blocked from light, not only the conventional mold opening and closing operations and the rotation operation of the rotary table but also the injection operation and the supply operation must be prohibited.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] If the light curtain on the operator's side is blocked in accordance with the established JIS standards, and the injection and supply operations are stopped, the greatest advantage of a rotary table type injection molding machine—the ability to remove products during molding and insert workpieces—becomes impossible. Furthermore, if the light curtain is positioned to avoid interfering with the mold on the near side where workpiece insertion and other processes are performed, the safety distance stipulated by JIS standards becomes insufficient.

[0007] This invention has been made in view of the above circumstances, and aims to achieve the objective of enabling efficient injection molding without unnecessarily extending the cycle time, while meeting safety standards. [Means for solving the problem]

[0008] (1) The control method for the injection molding machine of the present invention is as follows: A control method for an injection molding machine having a clamping device for clamping an upper mold and a lower mold, The mold clamping device comprises a rotary table to which a plurality of lower molds are attached, a fixed platen fixed to the machine body and rotatably supporting the rotary table from below, a movable platen provided above the fixed platen and fixed to the upper end of a tie bar to which the upper mold is attached, a rotation mechanism for rotating the rotary table, and a lifting mechanism for raising and lowering the movable platen. A clamping area is formed where the upper mold and one of the lower molds are clamped together by the raising and lowering of the movable platen, and a molded product removal area is formed where the molded product formed in the clamping area is removed. An intrusion detection sensor is provided between the mold clamping area and the molded product removal area to detect intrusion from the molded product removal area into the mold clamping area, A front intrusion detection sensor that detects intrusion into the molded product removal area from the outside, A clamping detection sensor for detecting the clamping state between the upper mold and one of the lower molds, It has, When the clamping state is detected by the clamping detection sensor, the intrusion is detected by the rear intrusion detection sensor, If the clamping detection sensor detects that clamping is not taking place, the system switches to detecting intrusion using the front intrusion detection sensor. This resolved the above issues. (2) The control method for the injection molding machine of the present invention is as described in (1) above, The lifting mechanism comprises: an end plate fixed to the lower end of the tie bar below the fixed platen and moving freely up and down together with the movable platen relative to the fixed platen; a screw shaft positioned vertically below the fixed platen, with its upper end pivotally supported by the fixed platen to prevent axial movement, and rotated circumferentially by a drive source; a crosshead screwed onto the screw shaft so as to move up and down; and a toggle mechanism provided between the fixed platen and the end plate, which extends and retracts as the crosshead moves up and down to open and close the movable platen. The mold clamping detection sensor can detect mold clamping by detecting the position of the crosshead when the upper mold and one of the lower molds are clamped together. (3) The control method for the injection molding machine of the present invention is as described in (1) above, When the clamping detection sensor detects that clamping has occurred, the front intrusion detection sensor switches to a state where it does not detect intrusion. It is possible. (4) The control method for the injection molding machine of the present invention is as described in (1) above, When performing an injection operation on the upper mold and one of the lower molds, the intrusion is detected by the rear intrusion detection sensor. It is possible. (5) The control method for the injection molding machine of the present invention is as described in (1) above, The rear intrusion detection sensor detects intrusion at a position in the molded product removal area that is closer to the clamping area than to the lower mold. It is possible.

[0009] According to the configuration described in (1) above, the clamping state is detected by the clamping detection sensor, and intrusion detection is switched between the rear intrusion detection sensor and the front intrusion detection sensor. This makes it possible to simultaneously perform the process of an operator entering the molded product removal area during the injection molding process, while also performing safety management at the same time. As a result, it becomes possible to perform injection, molded product removal, and workpiece insertion simultaneously in the injection molding machine while conducting safety management in accordance with JIS standards.

[0010] According to the configuration described in (2) above, the clamping of the upper and lower molds is confirmed by detecting the position of the crosshead that drives the toggle mechanism that moves the movable platen, which moves together with the upper mold, and the end plate, which moves together with the tie bar, in an extendable motion, at the moment the upper and lower molds come into contact. In practice, detection can be reliably achieved by detecting slightly before the point of contact. This makes it possible to reliably maintain a state that ensures both workability and safety when switching between intrusion detection by the rear intrusion detection sensor and the front intrusion detection sensor.

[0011] According to the configuration described in (3) above, the clamping detection sensor detects when the mold is clamped and also detects when the mold is released. This makes it possible to reliably maintain a safe state when switching between intrusion detection by the rear intrusion detection sensor and the front intrusion detection sensor.

[0012] According to the configuration described in (4) above, intrusion detection is performed by the rear intrusion detection sensor instead of the front intrusion detection sensor during the injection operation, thereby ensuring safety while simultaneously performing injection, removal of the molded product, and insertion of the workpiece.

[0013] According to the configuration of (5) above, even when an operator performs work on the lower mold in the molded product take-out area, the operator will not cause the backside intrusion detection sensor to detect an intrusion. As a result, during the injection operation, it becomes possible to simultaneously perform the take-out of the molded product and the insertion of the workpiece while ensuring safety.

Advantages of the Invention

[0014] According to the present invention, it is possible to achieve the effect of providing a control method for an injection molding machine that can simultaneously perform injection, take-out of the molded product, and insertion of the workpiece while satisfying the safety standards in the JIS standard.

Brief Description of the Drawings

[0015] [Figure 1] It is a front view showing an embodiment of an injection molding machine according to the present invention. [Figure 2] It is a side view showing the molded product take-out area, the mold clamping area, the backside intrusion detection sensor, and the frontside intrusion detection sensor in an embodiment of an injection molding machine according to the present invention. [Figure 3] It is a top view showing the mold clamping detection sensor and others in an embodiment of an injection molding machine according to the present invention. [Figure 4] It is a front view showing the operation of the mold clamping detection sensor in an embodiment of an injection molding machine according to the present invention. [Figure 5] It is a flowchart showing an embodiment of a control method for an injection molding machine according to the present invention. [Figure 6] It is a top view showing the operation in an embodiment of a control method for an injection molding machine according to the present invention. [[ID=3!]] [Figure 7] It is a front view showing the operation in an embodiment of a control method for an injection molding machine according to the present invention. [Figure 8] It is a front view showing the operation in an embodiment of a control method for an injection molding machine according to the present invention. [Figure 9] It is a top view showing the operation in an embodiment of a control method for an injection molding machine according to the present invention. [Figure 10]This is a front view showing the operation of an embodiment of the control method for an injection molding machine according to the present invention. [Figure 11] This is a front view showing the operation of an embodiment of the control method for an injection molding machine according to the present invention. [Modes for carrying out the invention]

[0016] Hereinafter, embodiments of the control method for an injection molding machine according to the present invention will be described with reference to the drawings. Figure 1 is a front view showing the injection molding machine of this embodiment. Figure 2 is a side view showing the molded product removal area, clamping area, etc., in the injection molding machine of this embodiment. Figure 3 is a top view showing the clamping detection sensor, etc., in the injection molding machine of this embodiment. In the figures, reference numeral 10 denotes the injection molding machine. The X, Y, and Z directions are perpendicular to each other. The X and Y directions represent the horizontal direction, and the Z direction represents the vertical direction. The Y direction is sometimes referred to as the front-back direction. The X direction is sometimes referred to as the left-right direction or lateral direction.

[0017] As shown in Figures 1 to 3, the injection molding machine 10 according to this embodiment has a movable platen 3 fixed to the upper end of a tie bar 4 above a fixed platen 1a and a rotary table 2 fixed to a machine body 1, and an end plate 5 fixed to the lower end of a tie bar 4 below the fixed platen 1a, so as to move up and down together with the movable platen 3 relative to the fixed platen 1a and the rotary table 2.

[0018] The end plate 5 has a roughly triangular outline when viewed from above. The rear of the end plate 5 in the Y direction is a side that aligns with the X direction. The center of the end plate 5 in the X direction is a corner that protrudes toward the front in the Y direction. Tie bars 4 are positioned near the three corners of the end plate 5.

[0019] The end plate 5, the fixed platen 1a, the rotary table 2, and the movable platen 3 extend approximately horizontally. The end plate 5, the fixed platen 1a, the rotary table 2, and the movable platen 3 are approximately parallel. The tie bars 4 extend approximately vertically. Multiple tie bars 4 are arranged. Multiple tie bars 4 are arranged spaced apart horizontally. For example, three tie bars 4 are arranged.

[0020] A lower mold (mold) 7 is attached to a rotary table 2, which is installed parallel to the fixed platen 1a. The rotary table 2 is rotatable around its vertical axis. The rotary table 2 is driven to rotate by a rotation mechanism (not shown) so that it can stop at a predetermined angular position. The lower mold (mold) 7 consists of a lower mold (mold) 7A and a lower mold (mold) 7B. The lower molds 7A and 7B are positioned on the rotary table 2 spaced apart in the Y direction. The lower molds 7A and 7B are positioned rotationally symmetrically with respect to the rotation axis of the rotary table 2. The lower mold 7A is sometimes referred to as type A, and the lower mold 7B as type B.

[0021] An upper mold (mold) 8 is attached to the movable platen 3. A nozzle (injection device) 9 is connected to the upper mold 8. Injection molding is performed using the upper mold 8 and the lower mold 7. During injection molding, the rotation of the rotary table 2 causes the lower mold 7A or lower mold 7B to rotate to a position corresponding to the upper mold 8. As the rotary table 2 rotates, injection molding can be performed using either the upper mold 8 and the lower mold 7A, or the upper mold 8 and the lower mold 7B.

[0022] A cover C is erected above the fixed platen 1a, surrounding its perimeter. The cover C has a front opening on its front surface in the Y direction. The front opening of the cover C is sized and shaped to allow a worker to enter the area above the fixed platen 1a and perform work. The entire area above the cover C is open. As will be described later, a rear intrusion detection sensor 40 and a front intrusion detection sensor 50 are positioned close together on the cover C.

[0023] Above the fixed platen 1a, a clamping area K1 and a molded product removal area K2 are formed (Figure 2). The clamping area K1 and the molded product removal area K2 are set up side by side in the Y direction. The clamping area K1 is located further back in the Y direction than the molded product removal area K2. The molded product removal area K2 is located closer to the Y direction than the clamping area K1. Here, "further back" and "closer to the front" refer to positions that are further away from an operator in front of the injection molding machine 10 in the Y direction, and similarly, positions that are closer to an operator.

[0024] The clamping area K1 and the molded product removal area K2 both have an X-direction length (width dimension) equal to the total length of the injection molding machine 10 in the X direction. The boundary between the clamping area K1 and the molded product removal area K2 is a straight line along the X direction. The boundary between the clamping area K1 and the molded product removal area K2 is close to the rotation axis of the rotary table 2. When the lower mold 7A is positioned in one area, the lower mold 7B can be positioned in the other area. When injection molding is performed using the upper mold 8 and the lower mold 7A, the lower mold 7B is positioned in the molded product removal area K2. When injection molding is performed using the upper mold 8 and the lower mold 7B, the lower mold 7A is positioned in the molded product removal area K2. The area arrangement of the lower mold 7A and the lower mold 7B is switched by the rotation of the rotary table 2.

[0025] The clamping area K1, when viewed from above, has a region that includes the movable platen 3. When viewed from above, the molded product removal area K2 is where the lower mold 7 that is not combined with the upper mold 8 is located. In other words, when the lower mold 7A is in the clamping area K1, the lower mold 7B is located in the molded product removal area K2. When the lower mold 7B is in the clamping area K1, the lower mold 7A is located in the molded product removal area K2. An ejector 71 is provided in the molded product removal area K2 for removing the molded product from the mold 7 (Figure 2). The ejector 71 removes the molded product from the mold 7 located in the molded product removal area K2. The ejector 71 can move forward and backward through the mold 7 and releases the molded product from the mold 7. The ejector 71 can move forward and backward in the Z direction.

[0026] A rear-side intrusion detection sensor 40 is positioned at the boundary between the mold clamping area K1 and the molded product removal area K2. The rear intrusion detection sensor 40 is a so-called light curtain. The rear intrusion detection sensor 40 has a pair of irradiating and receiving parts. One irradiating part emits sensor light, such as laser light, which is received by the receiving part on the other side. When an object enters the optical path of the laser light, the rear intrusion detection sensor 40 blocks the laser light. The rear intrusion detection sensor 40 detects intrusion by blocking the laser light.

[0027] The rear intrusion detection sensor 40 emits laser light along the X direction. This laser light is approximately horizontal. The rear intrusion detection sensor 40 has multiple irradiation units. The multiple irradiation units are arranged spaced apart in the Z direction. The multiple laser beams are emitted approximately parallel to each other. The rear intrusion detection sensor 40 is configured such that the spacing of the irradiation parts in the Z direction is large enough to detect the fingers of an operator. The rear intrusion detection sensor 40 is configured such that the spacing of the laser beams in the Z direction is within the range of 5 mm to 35 mm, or 10 mm to 30 mm, or 15 mm to 25 mm.

[0028] The rear intrusion detection sensor 40 has a detection range in the Z direction, with the upper limit being a position higher than the movable range of the upper surface of the movable platen 3 and the lower limit being the height of the upper mold 8 and lower mold 7 combined. The lower limit of the detection range in the Z direction of the rear intrusion detection sensor 40 is not affected by the workpiece or molded product placed on the rotary table 2. The rear intrusion detection sensor 40 has a detection range in the X direction that is equal to the total length of the fixed plate 1a in the X direction. The rear intrusion detection sensor 40 can detect intrusion along the entire length between the covers C on both sides in the X direction. Both the illuminating unit and the light receiving unit are located near the covers C on both sides in the X direction.

[0029] The front intrusion detection sensor 50 is positioned at the Y-direction front boundary of the molded product removal area K2. The front intrusion detection sensor 50 is a so-called light curtain. The front intrusion detection sensor 50 has a pair of irradiating and receiving parts. One irradiating part emits sensor light, such as laser light, which is received by the receiving part on the other side. When something enters the optical path of the laser light, the front intrusion detection sensor 50 blocks the laser light. The front intrusion detection sensor 50 detects intrusion by blocking the laser light.

[0030] The front intrusion detection sensor 50 emits laser light along the X direction. This laser light is approximately horizontal. The front intrusion detection sensor 50 has multiple irradiation units. The multiple irradiation units are arranged spaced apart in the Z direction. The multiple laser beams are emitted approximately parallel to each other. The front intrusion detection sensor 50 is configured such that the spacing of the irradiation sections in the Z direction is large enough to detect the fingers of an operator. The spacing of the laser beams in the Z direction of the front intrusion detection sensor 50 is configured to be in the range of 5 mm to 35 mm, or 10 mm to 30 mm, or 15 mm to 25 mm.

[0031] The front intrusion detection sensor 50 is set so that its detection range in the Z direction matches the vertical dimension of the front opening of the cover C in the Z direction. The detection range of the front intrusion detection sensor 50 in the X direction is set to be equal to the front opening of the cover C in the X direction. The illuminating part and the light receiving part of the front intrusion detection sensor 50 are both positioned near both sides of the front opening of the cover C in the X direction. The front intrusion detection sensor 50 is sometimes referred to as sensor A, and the rear intrusion detection sensor 40 as sensor B.

[0032] Two sets of toggle mechanisms 11 are connected to the fixed plate 1a and the end plate 5. The two sets of toggle mechanisms 11 are configured to be approximately symmetrical. The toggle mechanism 11 includes a toggle pin 12, a toggle piece 13, a toggle pin 14, a toggle pin 15, a face piece 16, a connecting pin 17, a connecting piece 18, a connecting pin 19, a cross head 20, and a screw shaft 22.

[0033] The toggle pin 12 extends horizontally. The toggle pin 12 is attached by a support portion at one end of the toggle piece 13. The toggle piece 13 is attached to the lower surface of the mounting plate 1a via the toggle pin 12. The toggle piece 13 is mounted so as to be rotatable up and down by the toggle pin 12. The toggle pin 14 extends horizontally. The toggle pin 14 is parallel to the toggle pin 12. The toggle pin 14 is attached to the end plate 5 by one end of a support portion located on the upper surface of the end plate 5. In a plan view, the toggle pin 14 is located directly below the toggle pin 12.

[0034] The facepiece 16 is attached to the upper surface of the end plate 5 by a toggle pin 14. The facepiece 16 is rotatably mounted vertically by the toggle pin 14. The toggle pin 14 is located in the middle of the facepiece 16. One end of the facepiece 16 is connected to the toggle piece 13. One end of the facepiece 16 is connected to the toggle piece 13 by a toggle pin 15.

[0035] The toggle pin 15 extends horizontally. It is parallel to the toggle pins 14 and 12. The toggle pin 15 is attached to a support at one end of the toggle piece 13. The toggle pin 15 connects the toggle piece 13 to the facepiece 16. The toggle piece 13 and face piece 16 can be bent up and down by the toggle pin 15.

[0036] The screw shaft 22 is supported by a bearing 23 in the fixed plate 1a. The screw shaft 22 is in a state where its axial movement is stopped. The screw shaft 22 is provided to be rotatable in the circumferential direction. The screw shaft 22 is provided vertically. The screw shaft 22 is preferably a ball screw shaft or a roller screw shaft. The nut on the screw shaft 22 is connected to the other end of the facepiece 16 via the crosshead 20, connecting pin 17, connecting piece 18, and connecting pin 19.

[0037] The crosshead 20 is screwed onto a nut on the screw shaft 22. The crosshead 20 is guided by several guide rods (not shown) that are fixed vertically to the fixed platen 1a or machine body 1. The crosshead 20 moves vertically in accordance with the rotation of the screw shaft 22.

[0038] A driven pulley is attached to the end of the screw shaft 22. The driven pulley is connected to a drive pulley by a timing belt. The drive pulley is rotationally driven by a drive motor such as a servo motor. The driven pulley, drive pulley, and belt constitute a transmission mechanism that transmits the rotation of the drive motor to the screw shaft 22. The transmission mechanism may also use other transmission members such as gears.

[0039] The mounting positions of the driven pulley, the drive pulley, and the drive motor are not particularly limited. For example, the driven pulley may be mounted on either end of the screw shaft 22. In this case, the position of the drive motor can also be changed accordingly.

[0040] Multiple tie bars 4 are arranged. Two or more tie bars 4 are arranged. Four tie bars 4 may be arranged. The lower end of each tie bar 4 is screwed into an adjustment nut 4a. Rotating the adjustment nut 4a adjusts the distance between the movable platen 3 and the rotary table 2. By rotating the adjustment nut 4a, the distance can be adjusted to match the thickness of the molds 7 and 8.

[0041] A mold clamping detection sensor 60 is attached to the end plate 5. A detection dog is attached to the crosshead 20. The detection dog is mounted in a position and shape such that the output signal from the mold clamping detection sensor 60 can be switched between a detection signal and a release signal slightly before the upper mold 8 and the lower mold 7 come into contact. The mold clamping detection sensor 60 detects the position of the crosshead 20 slightly before the upper mold 8 and the lower mold 7 come into contact. At this time, the output signal of the mold clamping detection sensor 60 switches from a release signal to a detection signal. The crosshead 20 extends the toggle mechanism by moving further down from the above position, and moves the end plate to its lower limit, pressing the upper mold 8 against the lower mold 7 and completing the mold clamping process. During this time, the output signal of the mold clamping detection sensor 60 remains a detection signal. In other words, the mold clamping detection sensor 60 detects whether the state is from slightly before the upper mold 8 and the lower mold 7 come into contact to the completed mold clamping state. The position slightly before contact to the completed clamping state is defined as the clamped state.

[0042] The clamping detection sensor 60 is a contact-type limit switch sensor. The sensor body of the clamping detection sensor 60 is attached to the end plate 5. The detection dog of the clamping detection sensor 60 is positioned on the crosshead 20. The arrangement of the sensor body and the detection dog of the clamping detection sensor 60 may be reversed. The clamping detection sensor 60 outputs a detection signal indicating that the clamping state is reached when the sensor body is driven by the detection dog. The clamping detection sensor 60 outputs a release signal indicating that the clamping state is released when the sensor body is not driven by the detection dog.

[0043] The clamping detection sensor 60 outputs a detection signal indicating that the clamping state is reached when the crosshead 20 descends and approaches the end plate 5 and the sensor body is driven by the detection dog. The clamping detection sensor 60 outputs a release signal indicating that the clamping state is released when the crosshead 20 rises and moves away from the end plate 5 and the sensor body is not driven by the detection dog.

[0044] In the toggle-type clamping device of the electric vertical injection molding machine (molding machine) 10, the screw shaft 22 is rotated by the drive motor during clamping. As a result of the rotation of the screw shaft 22, the crosshead 20 screwed onto the nut moves downward, causing the toggle mechanism 11 to extend linearly. When the toggle mechanism 11 extends linearly, the end plate 5 descends. When the end plate 5 descends, the movable platen 3 also descends simultaneously. When the movable platen 3 descends, the upper mold 8 contacts and presses against the lower mold 7 between itself and the rotary table 2. The upper mold 8 and the lower mold 7 are then in the clamped state.

[0045] In the toggle-type mold clamping device of the injection molding machine 10, the toggle mechanism 11 is folded when the mold is open (see Figure 4, right side). When the mold is open, the vertical dimension of the toggle mechanism 11 is reduced. The toggle-type clamping device of the injection molding machine 10 rotates the screw shaft 22 by operating the drive motor when changing from the open state to the clamped state. The rotation of the screw shaft 22 causes the crosshead 20 to descend. As the crosshead 20 descends, the connecting piece 18 also descends. The descending connecting piece 18 pushes down the inner end of the facepiece 16.

[0046] As a result, the facepiece 16 and toggle piece 13 rotate around the toggle pins 14 and 12 as pivot points. The facepiece 16 and toggle piece 13 rotate inward. The rotation of the facepiece 16 and toggle piece 13 brings the toggle pin 15 closer to the screw shaft 22. The facepiece 16 and toggle piece 13 extend and become closer to a straight line. As the toggle mechanism 11 extends straight, the end plate 5 descends. As a result, the movable platen 3 descends together with the end plate 5. The movable platen 3 moves downward to clamp the mold. The toggle piece 13 and face piece 16 extend in a straight line, completing the mold clamping.

[0047] In the toggle-type clamping device of the injection molding machine 10, the toggle mechanism 11 is extended when the mold is clamped (see left side of Figure 4). When the mold is clamped, the toggle mechanism 11 has its longest vertical dimension. The toggle-type mold clamping device of the injection molding machine 10 rotates the screw shaft 22 by operating the drive motor when changing from the mold clamped state to the mold open state. At this time, the screw shaft 22 rotates in the opposite direction to when changing from the mold open state to the mold clamped state. The rotation of the screw shaft 22 causes the crosshead 20 to rise. As the crosshead 20 rises, the connecting piece 18 rises as well. The rising connecting piece 18 pushes up the inner end of the facepiece 16.

[0048] As a result, the facepiece 16 and toggle piece 13 rotate around the toggle pins 14 and 12 as pivot points. The facepiece 16 and toggle piece 13 rotate outward. The rotation of the facepiece 16 and toggle piece 13 causes the toggle pin 15 to move away from the screw shaft 22. The facepiece 16 and toggle piece 13 bend from a straight line. As the toggle mechanism 11 bends from a straight line, the end plate 5 rises. As a result, the movable platen 3 rises together with the end plate 5. The movable platen 3 moves upward in the open mold. The toggle piece 13 and face piece 16 bend to complete the open mold.

[0049] Figure 4 is a front view showing the operation of the mold clamping detection sensor in the injection molding machine of this embodiment. In the injection molding machine 10 of this embodiment, as shown in Figure 4, when the movable platen 3 is opened and closed by the operation of the toggle mechanism 11, the clamping detection sensor 60 outputs a detection signal to indicate that the upper mold 8 and the lower mold 7 are in a clamped state, and outputs a release signal when it detects that the clamping has been released. The detection signal from the clamping detection sensor 60 is emitted at a position slightly before the upper mold 8 and the lower mold 7 come into contact with each other, after which the upper mold 8 further presses against the lower mold 7, applying a clamping force. In other words, the timing of the detection signal from the clamping detection sensor 60 does not coincide with the timing of stopping the rotation of the screw shaft 22. The detection signal from the mold clamping detection sensor 60 maintains its output while the mold clamping state is in place. The release signal from the mold clamping detection sensor 60 maintains its output while the mold is open.

[0050] In the injection molding machine 10 of this embodiment, intrusion is detected by the rear intrusion detection sensor 40 when the mold is clamped, and by the front intrusion detection sensor 50 when the mold is open. The switching between detection by the rear intrusion detection sensor 40 and the front intrusion detection sensor 50 is performed by detection signals and release signals output from the mold clamping detection sensor 60. Details of the switching between detection by the rear intrusion detection sensor 40 and the front intrusion detection sensor 50 based on the detection signals and release signals output from the mold clamping detection sensor 60 will be described later. While the mold clamping sensor 60 is outputting a detection signal, the rear intrusion detection sensor 40 maintains intrusion detection. While the mold is open, and the release signal is output by the mold clamping detection sensor 60, the intrusion detection by the front intrusion detection sensor 50 is maintained.

[0051] In the injection molding machine 10 of this embodiment, when the mold is open, the rotary table 2 is rotated to swap the positions of the lower mold 7A and the lower mold 7B. This allows the lower mold 7 on which the molded product injected between it and the upper mold 8 is placed to move towards the front, and the lower mold 7 on which the worker has placed the workpiece to move towards the back.

[0052] Figure 5 is a flowchart showing an embodiment of the control method for the injection molding machine according to this embodiment. The control method for the injection molding machine of this embodiment is as shown in Figure 5: completion of mold B molding S10b, start of mold B opening S11a, completion of mold B opening S11b, cycle start button operation S30, table rotation S21, start of mold A clamping S12a, completion of mold A clamping S12b, start of mold A injection S13a, mold B ejector advance S31, mold B molded product removal S32, mold B ejector retract S The machine includes 33, a B-type work insert S34, A-type molding completion S13b, A-type opening start S14a, A-type opening completion S14b, table rotation S22, B-type clamping start S15a, B-type clamping completion S15b, B-type injection start S16a, A-type ejector advance S35, A-type molded product removal S36, A-type ejector retract S37, and A-type work insert S38.

[0053] Figure 6 is a top view showing the operation of an embodiment of the injection molding machine control method according to this embodiment. Figure 7 is a front view showing the operation of an embodiment of the injection molding machine control method according to this embodiment. The control method for the injection molding machine in this embodiment will be described starting from the following state. First, in mold B completion S10b, as shown in Figures 6 and 7, the lower mold 7B is in the clamping area K1. The lower mold 7B is in the clamped state. The lower mold 7B is in the completed molding state. The lower mold 7A is in the molded product removal area K2. The lower mold 7A is in the pre-molding preparation state with the workpiece inserted. Since the lower mold 7B is in the clamped state, the clamping detection sensor 60 is outputting a detection signal. Therefore, the rear intrusion detection sensor 40 is in the intrusion detection state. The front intrusion detection sensor 50 is in the off state for detection to the rear. Therefore, the molded product removal area K2 is accessible to workers, and the device will not stop even if a worker enters the molded product removal area K2.

[0054] Figure 8 is a front view showing the operation of an embodiment of the control method for an injection molding machine according to this embodiment. Next, at mold opening start S11a, the mold clamping device is activated, and the mold clamping state of the lower mold 7B is released, as shown in Figure 8. Then, at mold clamping detection end S41, the detection of intrusion by the rear intrusion detection sensor 40 is switched to detection by the front intrusion detection sensor 50. At the end of mold clamping detection S41, the mold clamping detection sensor 60 stops outputting the detection signal and outputs a release signal. Here, the state of stopping the output of the detection signal and outputting the release signal in the mold clamping detection sensor 60 starts from the position where the crosshead 20 rises and the pressing and contact of the upper mold 8 with the lower mold 7 is released, is maintained while the crosshead 20 is moving upward, and is also maintained while the crosshead 20 is stopped in the raised position. Along with the stopping of the output of the detection signal and output of the release signal in the mold clamping detection sensor 60, the intrusion detection state of the rear intrusion detection sensor 40 is released. At the same time, the intrusion detection state of the front intrusion detection sensor 50 is started.

[0055] Next, in mold opening completion S11b, the crosshead 20 stops in the raised position. The upper mold 8 and the lower mold 7B separate. The output of the detection signal and the release signal from the mold clamping detection sensor 60 are maintained. The intrusion detection release from the rear intrusion detection sensor 40 and the intrusion detection state from the front intrusion detection sensor 50 are maintained.

[0056] As cycle start button operation S30, the worker operates the cycle start button. More precisely, this operation starts the cycle of the injection molding machine 10.

[0057] Figure 9 is a top view showing the operation of an embodiment of the control method for an injection molding machine according to this embodiment. Next, as table rotation S21, the rotary table 2 rotates. The lower mold 7B moves from the clamping area K1 to the molded product removal area K2, as shown in Figure 9. The molded product completed in mold B molding completion S10b is placed on the lower mold 7B. The lower mold 7A moves from the molded product removal area K2 to the clamping area K1. The lower mold 7A is now in a position where it can be clamped below the upper mold 8. The output of the detection signal stop and the output of the release signal in the clamping detection sensor 60 are maintained. The intrusion detection release of the rear intrusion detection sensor 40 and the intrusion detection state of the front intrusion detection sensor 50 are maintained.

[0058] Next, at the start of mold clamping S12a, the mold clamping device is activated, releasing the open state of the lower mold 7B. The crosshead 20 descends, and the end plate 5 also descends. During the start of type A clamping S12a, the output of the detection signal and the release signal from the clamping detection sensor 60 are maintained. The intrusion detection release from the rear intrusion detection sensor 40 and the intrusion detection state by the front intrusion detection sensor 50 are maintained.

[0059] Figure 10 is a front view showing the operation of an embodiment of the control method for an injection molding machine according to this embodiment. Next, at the completion of mold clamping A (S12b), just before the upper mold 8 and lower mold 7A come into contact, the mold clamping detection sensor 60 outputs a detection signal and stops outputting a release signal, marking the start of mold clamping detection (S42). As the crosshead 20 moves further to its lower limit position, the mold clamping is completed, as shown in Figure 10. With the output of the detection signal and the cessation of the release signal from the mold clamping detection sensor 60, the detection by the rear intrusion detection sensor 40 and the detection by the front intrusion detection sensor 50 are switched. The intrusion detection state of the rear intrusion detection sensor 40 is started. At the same time, the intrusion detection state for the rear by the front intrusion detection sensor 50 is released. Here, the output state of the detection signal and the stop state of the release signal output in the clamping detection sensor 60 are started when the crosshead 20 is slightly before the upper mold 8 and the lower mold 7A come into contact, and are maintained even while the crosshead 20 is stopped at its lower limit position. For this reason, they are maintained even after the clamping force is applied to the upper mold 8 and the lower mold 7A.

[0060] Next, at the start of injection of type A, S13a, the injection process is initiated. During the start of injection molding (S13a), the output of the detection signal and the release signal from the clamping detection sensor 60 are maintained. The intrusion detection by the rear intrusion detection sensor 40 and the release of the rear intrusion detection by the front intrusion detection sensor 50 are maintained.

[0061] Next, in the B-type ejector advancement S31, the ejector 71 operates in the molded product removal area K2. The ejector 71 rises relative to the lower mold 7B in the molded product removal area K2 and ejects the molded product from the lower mold 7B. In the B-type ejector advancement S31, the output of the detection signal and the stop of the release signal output at the clamping detection sensor 60 are maintained. The intrusion detection by the rear intrusion detection sensor 40 and the release of the intrusion detection for the rear side by the front intrusion detection sensor 50 are maintained.

[0062] Next, in molded product removal S32, the molded product is removed from the lower mold 7B in molded product removal area K2 and taken out of the device. At this time, a worker enters the molded product removal area K2, but the intrusion detection deactivation for the rear side by the front intrusion detection sensor 50 is maintained. Simultaneously, the output of the detection signal and the deactivation signal output of the clamping detection sensor 60 are maintained. Intrusion detection by the rear intrusion detection sensor 40 is maintained, and there are no safety issues.

[0063] Next, in the B-type ejector retraction S33, the ejector 71 retracts in the molded product removal area K2. The ejector 71 descends relative to the lower mold 7B in the molded product removal area K2 and retracts from the lower mold 7B from which the molded product has been removed. In the B-type ejector retraction S33, the output of the detection signal and the stop of the release signal output at the mold clamping detection sensor 60 are maintained. The intrusion detection by the rear intrusion detection sensor 40 and the release of the intrusion detection for the rear side by the front intrusion detection sensor 50 are maintained.

[0064] Next, in the B-type work insert S34, the workpiece is supplied from outside the device to the lower mold 7B in the molded product removal area K2. At this time, an operator enters the molded product removal area K2 and places the workpiece in a predetermined position on the lower mold 7B, but the intrusion detection release for the rear side by the front intrusion detection sensor 50 is maintained. Simultaneously, the output of the detection signal and the deactivation of the release signal output by the clamping detection sensor 60 are maintained. Intrusion detection by the rear intrusion detection sensor 40 is maintained, and there are no safety issues. These B-type molded product removal S32 and B-type workpiece insert S34 can be carried out simultaneously with the injection molding process.

[0065] Next, at the completion of mold A formation S13b, the injection molding process is terminated. At the completion of mold A formation S13b, the output of the detection signal and the output of the release signal at the mold clamping detection sensor 60 are maintained. Intrusion detection by the rear intrusion detection sensor 40 and the release of intrusion detection for the rear side by the front intrusion detection sensor 50 are maintained.

[0066] Figure 11 is a front view showing the operation of an embodiment of the control method for an injection molding machine according to this embodiment. Next, at the start of mold opening S14a, the mold clamping device is activated, and the clamped state of the lower mold 7A is released, as shown in Figure 11. Then, at the end of mold clamping detection S43, the detection of intrusion by the rear intrusion detection sensor 40 is switched to detection by the front intrusion detection sensor 50. At the end of mold clamping detection S43, the mold clamping detection sensor 60 stops outputting the detection signal and outputs a release signal. Here, the state of stopping the output of the detection signal and outputting the release signal in the mold clamping detection sensor 60 starts from the position where the crosshead 20 rises and the pressing and contact of the upper mold 8 with the lower mold 7A is released, is maintained while the crosshead 20 is moving upward, and is also maintained while the crosshead 20 is stopped at the upper limit position. Along with the stopping of the output of the detection signal and output of the release signal in the mold clamping detection sensor 60, the intrusion detection state of the rear intrusion detection sensor 40 is released. At the same time, the intrusion detection state of the front intrusion detection sensor 50 is started.

[0067] Next, in mold opening completion S14b, the crosshead 20 stops at the completed upward position. The upper mold 8 and the lower mold 7B separate. The output of the detection signal and the release signal from the mold clamping detection sensor 60 are maintained. The intrusion detection release from the rear intrusion detection sensor 40 and the intrusion detection state by the front intrusion detection sensor 50 are maintained.

[0068] Next, as table rotation S22, the rotary table 2 rotates. The lower mold 7A moves from the clamping area K1 to the molded product removal area K2, as shown in Figure 6. The molded product completed in A-type molding completion S13b is placed on the lower mold 7A. The lower mold 7B moves from the molded product removal area K2 to the clamping area K1. The lower mold 7B is now in a position where it can be clamped below the upper mold 8. During table rotation S22, the output of the detection signal from the clamping detection sensor 60 is stopped and the output of the release signal is maintained. The intrusion detection release from the rear intrusion detection sensor 40 and the intrusion detection state from the front intrusion detection sensor 50 are maintained.

[0069] Next, at the start of mold clamping B S15a, the mold clamping device is activated, releasing the open state of the lower mold 7B. The crosshead 20 descends, and the end plate 5 also descends. During the start of type B clamping S15a, the output of the detection signal and the release signal from the clamping detection sensor 60 are maintained. The intrusion detection release from the rear intrusion detection sensor 40 and the intrusion detection state by the front intrusion detection sensor 50 are maintained.

[0070] Next, at the completion of mold clamping B (S15b), just before the upper mold 8 and lower mold 7B come into contact, the mold clamping detection sensor 60 outputs a detection signal and stops outputting a release signal (S42). As the crosshead 20 moves further to its lower limit position, the mold clamping is completed, as shown in Figure 7. With the output of the detection signal and the cessation of the release signal from the mold clamping detection sensor 60, the detection by the rear intrusion detection sensor 40 and the detection by the front intrusion detection sensor 50 are switched. The intrusion detection state of the rear intrusion detection sensor 40 is started. At the same time, the intrusion detection state for the rear by the front intrusion detection sensor 50 is released. Here, the output state of the detection signal and the output stop state of the release signal in the clamping detection sensor 60 are started when the crosshead 20 is slightly before the upper mold 8 and the lower mold 7B come into contact, and are maintained even when the crosshead 20 is stopped at its lower limit position. For this reason, they are maintained even after the clamping force is applied to the upper mold 8 and the lower mold 7B.

[0071] Next, at the start of injection of type B, S16a, the injection process is initiated. During the start of injection molding (S16a), the output of the detection signal and the release signal from the clamping detection sensor 60 are maintained. The intrusion detection by the rear intrusion detection sensor 40 and the release of the rear intrusion detection by the front intrusion detection sensor 50 are maintained.

[0072] Next, in the A-type ejector advancement S35, the ejector 71 operates in the molded product removal area K2. The ejector 71 rises relative to the lower mold 7A in the molded product removal area K2 and ejects the molded product from the lower mold 7A. In the A-type ejector advancement S35, the output of the detection signal and the stop of the release signal output at the mold clamping detection sensor 60 are maintained. The intrusion detection by the rear intrusion detection sensor 40 and the release of the intrusion detection for the rear side by the front intrusion detection sensor 50 are maintained.

[0073] Next, in molded product removal S36, the molded product is removed from the lower mold 7A in molded product removal area K2 and taken out of the device. At this time, a worker enters the molded product removal area K2, but the intrusion detection deactivation for the rear side by the front intrusion detection sensor 50 is maintained. Simultaneously, the output of the detection signal and the deactivation signal output of the clamping detection sensor 60 are maintained. Intrusion detection by the rear intrusion detection sensor 40 is maintained, and there are no safety issues.

[0074] Next, in the retraction of the A-type ejector S37, the ejector 71 retracts in the molded product removal area K2. The ejector 71 descends relative to the lower mold 7A in the molded product removal area K2 and retracts from the lower mold 7A from which the molded product has been removed. In the retraction of the A-type ejector S37, the output of the detection signal and the stop of the release signal output at the clamping detection sensor 60 are maintained. The intrusion detection by the rear intrusion detection sensor 40 and the release of the intrusion detection for the rear side by the front intrusion detection sensor 50 are maintained.

[0075] Next, in the A-type workpiece insert S38, the workpiece is supplied from outside the device to the lower mold 7A in the molded product removal area K2. At this time, an operator enters the molded product removal area K2 and places the workpiece in a predetermined position on the lower mold 7A, but the intrusion detection release for the rear side by the front intrusion detection sensor 50 is maintained. Simultaneously, the output of the detection signal and the deactivation of the release signal output by the clamping detection sensor 60 are maintained. Intrusion detection by the rear intrusion detection sensor 40 is maintained, and there are no safety issues. These A-type molded product removal S36 and A-type workpiece insert S38 can be carried out simultaneously with the injection molding process.

[0076] Next, we return to the completion of mold B (S10b) and end the cycle in the injection molding machine control method of this embodiment. In the injection molding machine control method of this embodiment, the above cycle is repeated.

[0077] In the control method of the injection molding machine of this embodiment, the mold clamping detection sensor 60 detects the mold clamping state and the mold opening state and outputs a detection signal and a release signal. In response to these signals, it is possible to switch between intrusion detection by the rear intrusion detection sensor 40 and intrusion detection by the front intrusion detection sensor 50. As a result, in the mold clamping process, the table rotation process, and the ejector retraction process, intrusion detection is performed by the front intrusion detection sensor 50 to ensure safety in the molded product removal area K2. In the injection process, where work by an operator is required in the molded product removal area K2, the system can be switched to detect intrusion by the rear intrusion detection sensor 40, thereby ensuring safety in accordance with JIS standards. At the same time, injection molding can be performed without reducing the manufacturing efficiency of the injection molding machine 10. [Explanation of Symbols]

[0078] 10...Injection molding machine 1…Machine body 1a…Fixed board 2… Rotating table 3…Movable plate 4…Tie bar 5… End plate 7, 7A, 7B... Lower mold (mold) 8… Upper mold (mold) 11...Toggle mechanism 12, 14, 15… Toggle pins 13...Toggle piece 16… Facepiece 17…Connecting pin 18…Connecting pieces 20…Crosshead 22... Screw shaft 40... Intrusion detection sensor on the back side 50…Front intrusion detection sensor 60... Clamping detection sensor K1... Clamping area K2... Molded product removal area

Claims

1. A control method for an injection molding machine having a clamping device for clamping an upper mold and a lower mold, The mold clamping device comprises a rotary table to which a plurality of lower molds are attached, a fixed platen fixed to the machine body and rotatably supporting the rotary table from below, a movable platen provided above the fixed platen and fixed to the upper end of a tie bar to which the upper mold is attached, a rotation mechanism for rotating the rotary table, and a lifting mechanism for raising and lowering the movable platen. A clamping area is formed where the upper mold and one of the lower molds are clamped together by the raising and lowering of the movable platen, and a molded product removal area is formed where the molded product formed in the clamping area is removed. An intrusion detection sensor is provided between the mold clamping area and the molded product removal area to detect intrusion from the molded product removal area into the mold clamping area, A front intrusion detection sensor that detects intrusion into the molded product removal area from the outside, A clamping detection sensor for detecting the clamping state between the upper mold and one of the lower molds, It has, When the clamping state is detected by the clamping detection sensor, the intrusion is detected by the rear intrusion detection sensor, If the clamping detection sensor detects that clamping is not taking place, the system switches to detecting intrusion using the front intrusion detection sensor. A control method for an injection molding machine characterized by the following:

2. The lifting mechanism comprises: an end plate fixed to the lower end of the tie bar below the fixed platen and moving freely up and down together with the movable platen relative to the fixed platen; a screw shaft positioned vertically below the fixed platen, with its upper end pivotally supported by the fixed platen to prevent axial movement, and rotated circumferentially by a drive source; a crosshead screwed onto the screw shaft so as to move up and down; and a toggle mechanism provided between the fixed platen and the end plate, which extends and retracts as the crosshead moves up and down to open and close the movable platen. The mold clamping detection sensor detects mold clamping by detecting the position of the crosshead in the clamped state of the upper mold and one of the lower molds. The method for controlling an injection molding machine according to feature 1.

3. When the clamping detection sensor detects that clamping has occurred, the front intrusion detection sensor switches to a state where it does not detect intrusion. The method for controlling an injection molding machine according to feature 1.

4. When performing an injection operation on the upper mold and one of the lower molds, the intrusion is detected by the rear intrusion detection sensor. The control method for an injection molding machine according to feature 3.

5. The rear intrusion detection sensor detects intrusion at a position in the molded product removal area that is closer to the clamping area than to the lower mold. A method for controlling an injection molding machine according to any one of the features described in 1 to 3.

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