TW201615380A - Injection molding machine - Google Patents

Abstract

This invention is an injection molding machine which can provide stability in the quality of a molded product. The injection molding machine comprises: a driving device of a compression component which is used for compressing a forming material inside a compression mold device, and a controller which is used to control the driving device. While in the middle of a compression path of compressing the forming material inside the mold device, the controller performs a switch over of the driving device control between positional control and pressure control.

Description

Injection molding machine

The present application claims priority based on Japanese Patent Application No. 2014-215728, filed on Oct. 22, 2014. The entire contents of this Japanese application are incorporated herein by reference.

The present invention relates to an injection molding machine.

An injection molding machine having a driving device for compressing a compression member of a molding material in a mold device (for example, see Patent Document 1) is known. By compressing the molding material by the compression member, a thin-walled molded article can be obtained.

(previous technical literature) (Patent Literature)

Patent Document 1: Japanese Laid-Open Patent Publication No. 2012-187769

Conventionally, the quality of a molded article obtained by compressing a molding material has a large variation.

The present invention has been made in view of the above problems, and a main object thereof is to provide an injection molding machine capable of stabilizing the quality of a molded article.

In order to solve the above problems, according to an aspect of the invention, there is provided an injection molding machine comprising: a driving device for compressing a member, the compression member for compressing a molding material in the mold device; and a controller for controlling the driving device, The controller switches between the control of the driving device and the pressure control while compressing the compression stroke of the molding material in the mold device.

According to an aspect of the invention, an injection molding machine capable of stabilizing the quality of a molded article is provided.

30‧‧‧Molding device

32‧‧‧Fixed mode

33‧‧‧ movable mold

34‧‧‧ cavity space

36‧‧‧Compressed components

40‧‧‧Injection device

42‧‧‧Forming materials

50‧‧‧Intermediate device

51‧‧‧ Block

60‧‧‧Ejecting device

61‧‧‧Out of the motor

61a‧‧‧Encoder

62‧‧‧Sports conversion mechanism

63‧‧‧Ejecting rod

64‧‧‧Top board

65‧‧‧ position sensor

66‧‧‧ Pressure Sensor

70‧‧‧ Controller

Fig. 1 is a view showing a state at the start of a compression stroke of the injection molding machine according to the embodiment of the present invention.

Fig. 2 is a view showing a state at the end of the compression stroke of the injection molding machine according to the embodiment of the present invention.

Fig. 3 is a flow chart showing the compression stroke of the injection molding machine according to the embodiment of the present invention.

The embodiments for carrying out the invention are described below with reference to the drawings, in which the same or corresponding components are designated by the same or corresponding elements, and the description is omitted.

Fig. 1 is a view showing a state at the start of a compression stroke of the injection molding machine according to the embodiment of the present invention. Fig. 2 is a view showing a state at the end of the compression stroke of the injection molding machine according to the embodiment of the present invention. As shown in FIGS. 1 and 2, the injection molding machine has a frame Fr, a mold clamping device 10, an injection device 40, an intermediate device 50, an ejection device 60, a controller 70, and the like.

The mold clamping device 10 performs mold closing, mold clamping, and mold opening of the mold device 30. The mold device 30 is composed of a fixed mold 32 and a movable mold 33. The mold clamping device 10 has a fixed platen 12, a movable platen 13, a rear platen 15, a tie rod 16, a toggle mechanism 20, a mold clamping motor 21, and a motion conversion mechanism 25. In the following description, the moving direction of the movable platen 13 at the time of mold closing (the right direction in the first drawing and the second drawing) is the front direction, and the moving direction of the movable platen 13 at the time of mold opening (Fig. 1 and Fig. 2) The middle is the left direction) and will be described as the rear.

The fixed platen 12 is fixed to the frame Fr. A fixed die 32 is attached to a surface of the fixed platen 12 that faces the movable platen 13.

The movable platen 13 is movably movable along a guide (e.g., a guide rail) 17 laid on the frame Fr, and is movable forward and backward with respect to the fixed platen 12. On the face of the movable platen 13 opposite to the fixed platen 12, through the middle The device 50 is mounted with a movable die 33.

The mold closing, mold clamping, and mold opening of the mold device 30 are performed by moving the movable platen 13 forward and backward with respect to the fixed platen 12.

The rear pressure plate 15 is coupled to the fixed pressure plate 12 with a space therebetween, and is movably placed on the frame Fr in the mold opening and closing direction. In addition, the rear platen 15 may be configured to be movable along a guide laid on the frame Fr. The guide of the rear platen 15 can be used in common with the guide 17 of the movable platen 13.

Further, in the present embodiment, the fixed platen 12 is fixed to the frame Fr, and the rear platen 15 is movable in the mold opening and closing direction with respect to the frame Fr. However, the rear platen 15 may be fixed to the frame Fr, and the fixed platen 12 may be fixed relative to the frame Fr. It can move freely along the mold opening and closing direction.

The tie rod 16 connects the fixed pressure plate 12 and the rear pressure plate 15 at intervals. A plurality of root tie rods 16 can be used. Each tie rod 16 is parallel to the mold opening and closing direction and extends corresponding to the mold clamping force. A mold clamping force detector 18 is provided on at least one of the tie bars 16. The mold clamping force detector 18 may be a strain ritual that detects the mold clamping force by detecting the deformation of the tie rod 16.

Further, the mold clamping force detector 18 is not limited to the strain ceremony, and may be a piezoelectric type, a capacitive type, a hydraulic type, an electromagnetic type or the like, and the mounting position thereof is not limited to the tie rod 16.

The toggle mechanism 20 is disposed between the movable platen 13 and the rear platen 15. The toggle mechanism 20 is composed of a crosshead 20a, a plurality of links 20b, 20c, and the like. One of the links 20b is swingably attached to the movable platen 13, and the other link 20c is swingably attached to the rear platen 15. These links 20b and 20c are connected to each other by a pin or the like so as to be expandable and contractible. By making The crosshead 20a advances and retreats, and the plurality of links 20b and 20c expand and contract, whereby the movable platen 13 advances and retreats relative to the rear platen 15.

The mold clamping motor 21 is attached to the rear pressure plate 15, and the movable platen 13 is advanced and retracted by advancing and retracting the crosshead 20a. Between the mold clamping motor 21 and the crosshead 20a, a motion conversion mechanism 25 that converts the rotational motion of the mold clamping motor 21 into a linear motion and transmits it to the crosshead 20a is provided. The motion converting mechanism 25 is constituted by, for example, a ball screw mechanism.

The operation of the mold clamping device 10 is controlled by the controller 70. The controller 70 controls the mold closing process, the mold clamping process, and the mold opening process.

In the mold closing process, the mold clamping motor 21 is driven to advance the movable platen 13, whereby the movable mold 33 is brought into contact with the fixed mold 32. A compression member 36 is disposed on the movable mold 33 side, and a cavity space 34 is formed between the compression member 36 and the fixed mold 32. The compression member 36 is configured to be retractable in the mold device 30.

In the mold clamping process, the mold clamping force is generated by further driving the mold clamping motor 21. When the mold is closed, the injection device 40 fills the cavity space 34 with the liquid molding material 42. The compression member 36 is moved in the mold device 30 in the middle of the filling, whereby the molding material 42 is compressed. After the filling process, the maintenance process and the cooling process are performed. During the holding process, pressure is applied to the forming material 42 in the cavity space 34. In the cooling process, the molding material 42 in the cavity space 34 is solidified to obtain a molded article.

In the mold opening process, the mold clamping motor 21 is driven to retract the movable platen 13, thereby separating the movable mold 33 from the fixed mold 32. After the mold opening process is completed, the ejector unit 60 ejects the molded article from the mold device 30.

The intermediate device 50 is disposed between the movable die 33 and the movable platen 13 . The intermediate device 50 has, for example, a block 51. The rear end portion of the compression member 36 is inserted into the internal space 51a of the block 51.

The ejector unit 60 ejects the molded article from the mold device 30 after the mold is opened. The ejector unit 60 has, for example, an ejector motor 61, a motion conversion mechanism 62, and an ejector rod 63.

The ejector motor 61 is attached to the rear of the movable platen 13. The ejector motor 61 has an encoder 61a. The encoder 61a detects the rotation angle of the output shaft of the ejector motor 61, and outputs a signal indicating the rotation angle to the controller 70.

The motion converting mechanism 62 converts the rotational motion of the ejector motor 61 into a linear motion of the ejector rod 63. The motion conversion mechanism 62 is constituted by, for example, a ball screw mechanism or the like.

The ejector rod 63 is configured to be retractable in the through hole of the movable platen 13. The front end portion of the ejector rod 63 is in contact with the rear end surface of the ejector plate 64.

The ejector plate 64 is configured to be retractable in the internal space 51a of the block body 51. The front end face of the ejector plate 64 is in contact with the rear end portion of the compression member 36.

The ejector motor 61 is driven to advance the ejector rod 63, thereby advancing the compression member 36. Further, the ejector motor 61 is driven to retract the ejector lever 63, whereby the compression member 36 is retracted.

The ejector unit 60 functions as a driving device of the compression member 36. The compression member 36 serves both for (1) molding of the molding material in the mold device 30, and for (2) ejection of the molded article from the mold device 30.

The controller 70 has a CPU (Central Processing Unit) 71 and Memory medium 72 such as memory. The controller 70 causes the CPU 71 to execute a program stored in the memory medium 72, thereby controlling the mold clamping device 10, the injection device 40, the ejection device 60, and the like.

The controller 70 switches the control of the ejector device 60 between position control and pressure control midway through the compression stroke of the forming material 42 within the compression cavity space 34. It is possible to switch from position control to pressure control or from pressure control to position control.

At the position control of the ejector unit 60, the ejector motor 61 is controlled such that the position of the compression member 36 or the member moving together with the compression member 36 becomes the set position. The control may be any of feedback control or feedforward control. The set position can be changed continuously or intermittently over time. Examples of the member that moves together with the compression member 36 include an ejector rod 63 and an ejector plate 64.

The position of the compression member 36 or the member that moves with the compression member 36 is detected by the position sensor 65. The position sensor 65 is attached to the member on the fixed side (for example, the block 51 of the intermediate device 50 in FIGS. 1 and 2), but may be attached to the movable member. Further, as the position sensor 65, the encoder 61a of the ejector motor 61 can be used.

On the other hand, in the pressure control of the ejector unit 60, the ejector motor 61 is controlled such that the pressure of the molding material 42 in the cavity space 34 becomes the set pressure. The control may be any of feedback control or feedforward control. The set pressure can be continuously or intermittently changed over time.

The pressure of the forming material 42 within the cavity space 34 is detected by the pressure sensor 66. The pressure sensor 66 is mounted on a movable side member (for example, 1 and 2 are the compression members 36), but they may be attached to the members on the fixed side (for example, the fixed mold 32). Further, the pressure sensor 66 can also detect the pressure of the molding material 42 in the cavity space 34 by detecting deformation of the constituent members of the ejector unit 60 or deformation of the constituent members of the intermediate device 50.

According to this embodiment, the position control and the pressure control are switched in the middle of the compression stroke. Therefore, it is possible to perform control corresponding to the filling state of the molding material 42 in the cavity space 34, and it is possible to stabilize the quality of the molded article. The compression stroke is divided into a plurality of processes by switching between position control and pressure control.

For example, controller 70 performs position control on at least one of the initial process and the final process in a plurality of processes.

By performing position control in the initial process, the compression member 36 can be surely advanced to the set position, and the molding material 42 can be expanded by the front surface of the compression member 36. Further, when the compression stroke is started, the pressure of the molding material 42 in the cavity space 34 is not sufficiently stabilized. The quality of the molded article is stabilized by position control in the initial process.

By performing pressure control in the middle process, the molding material 42 is sufficiently pressed against the wall surface of the cavity space 34 to improve transferability. Further, since the pressure of the molding material 42 is stabilized, the density of the molding material 42 is stabilized.

By performing position control in the final process, the final size and shape of the cavity space 34 become stable, and the size and shape of the molded article become stable. By advancing the compression member 36 in the final process, the cavity space 34 is The molding material 42 is filled to complete the filling of the molding material 42. After the filling process, the maintenance process and the cooling process are performed.

After the end of the compression stroke, the position control can be continued in the pressurization process and the cooling process to prevent the size of the cavity space 34 from changing. At this position control, the compression member 36 is prohibited from moving. This position control can also be carried out until the start of the mold opening process.

As shown in Fig. 3, the controller 70 can perform position control in both the initial process and the final process, and performs pressure control in the process between these processes. Further, in the third drawing, the position control S11, the pressure control S12, and the position control S13 are sequentially performed on the compression stroke, but the number of switching and the order are not particularly limited. For example, the controller 70 may end with the pressure control S12 without switching the pressure control S12 to the position control S13. That is, the position control S11 and the pressure control S12 may be performed only in sequence. Further, the controller 70 may first perform the pressure control S12 without performing the position control S11. That is, the pressure control S12 and the position control S13 may be performed only in sequence. The compression stroke may be composed of two or more processes, and for example, it may be composed of four or more processes.

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

For example, in the above embodiment, the compression member 36 is used for (1) the molding material in the compression mold device 30, and (2) the molded article is ejected from the mold device 30, but may be used only for (1) compression. Not used for (2) ejection. At this time, unlike the compression member 36, the member for ejection is additionally It is disposed outside the mold device 30.

When the ejector member and the compression member 36 are separately provided, the ejector unit 60 can function as a driving device that independently drives the ejector member and the compression member 36, and can also function as a driving device that drives only the ejector member. In the latter case, a driving device that drives the compression member 36 is additionally provided. For example, a hydraulic cylinder as the intermediate device 50 is used as a driving device for driving the compression member 36.

The compression member 36 of the above embodiment is disposed on the side of the movable mold 33, but may be disposed on the side of the fixed mold 32. At this time, the intermediate device 50 may be disposed between the fixed die 32 and the fixed platen 12. Further, the compression members 36 may be disposed on both sides of the movable mold 33 and the fixed mold 32, respectively.

The start time of the compression stroke in the above embodiment is in the middle of the filling molding material 42, but is not particularly limited. For example, it may be performed before the start of filling, or may be performed simultaneously with the start of filling.

The end time of the compression stroke in the above embodiment is substantially the same as the time at which the filling of the molding material 42 is completed, but is not particularly limited. For example, the filling may be completed after the filling is completed or before the filling is completed.

The mold clamping device 10 of the above embodiment has a mold clamping motor 21 as a drive source, but may have a hydraulic cylinder instead of the mold clamping motor 21. Further, the mold clamping device 10 may have a linear motor for mold opening and closing, and may have an electromagnet for mold clamping.

Claims (5)

An injection molding machine having: a driving device for compressing a member for compressing a molding material in a mold device; and a controller for controlling the driving device, wherein the controller compresses compression of a molding material in the mold device In the middle of the trip, the control of the aforementioned drive device is switched between position control and pressure control. The injection molding machine according to claim 1, wherein the compression stroke is divided into a plurality of processes by switching between the position control and the pressure control, and the controller is in the plurality of processes At least one of the initial process and the final process in the middle performs the aforementioned position control. The injection molding machine according to claim 2, wherein the controller performs the position control in the two processes of the first process and the last process, and performs the pressure on a process between the two processes. control. The injection molding machine according to any one of claims 1 to 3, wherein the driving device is an ejection device for ejecting a molded article from the mold device. The injection molding machine according to any one of claims 1 to 4, wherein the compression member is for ejecting a molded article from the mold device.