JP4771812B2 - Injection molding body molding method and injection molding apparatus - Google Patents

Description

  The present invention relates to a method for molding an injection molded body in which members made of different types of synthetic resins are integrally molded, and an injection molding apparatus that realizes the method.

  Conventionally, an injection molded body in which members made of different types of synthetic resins are integrally molded has been put to practical use. For example, the hole plug 60 shown in FIG. 4 includes a dish-shaped seal portion 62 made of a flexible synthetic resin and a fitting portion 64 made of a rigid synthetic resin located on the back side thereof. It is used for sealing a through hole or the like opened in a body of an automobile or the like.

  In order to mold such an injection-molded body, one movable mold that can move between two fixed molds by a moving mechanism is constituted, as represented by a turntable type or a linear reciprocating type (Patent Document 1). However, a method is generally used in which each synthetic resin is injected by sequentially moving it.

JP 2000-94488 A JP 2002-103376 A

  However, the injection molding method as described above requires two fixed molds, one movable mold, and a moving mechanism for moving the molds, so that there is a problem that a device for realizing it becomes coarse. . In addition to the clamping / opening operation of the movable mold, there is also a problem that it takes a long time to complete one product because the movement between the two fixed molds is necessary.

  Patent Document 2 discloses a technique for sequentially injecting various types of synthetic resin materials into one cavity of a mold without using such a moving mechanism. There is a problem that the interface shape between them is not stable.

  The present invention has been made in view of the above problems, and is capable of forming an injection molded body in which members made of different types of synthetic resins are integrally molded, which can be obtained satisfactorily and easily. It is an object to provide a method and an injection molding apparatus that realizes the method.

Means for solving the problems / effects of the invention

  In order to solve the above-described problems, a method for molding an injection-molded body according to the present invention is a method for molding an injection-molded body in which members made of different types of synthetic resins are integrally molded, and has a first molding surface. A first injection step of pressing the first mold against the wall body and injecting a first synthetic resin into a cavity constituted by the first molding surface and the wall surface of the wall body to mold the first member; A wall body retreating step of releasing the pressure contact between the first mold and the wall body and retracting the wall body while leaving the first member on the first mold side; and A second mold having two molding surfaces is clamped, a second synthetic resin is injected into a cavity constituted by the first molding surface and the second molding surface, and the second member is placed in the cavity. The second injection step of integrally molding with the first member is performed in this order.

  The injection molding apparatus of the present invention is an injection molding apparatus capable of obtaining an injection molded body in which members made of different types of synthetic resins are integrally molded, and has a first molding surface. A mold, a second mold having a second forming surface, and a wall body, and the first molding surface and the wall surface of the wall body in a state where the first mold is pressed against the wall body In a state where the first injection unit for injecting the first synthetic resin into the cavity constituted by the first member and molding the first member, the pressure contact between the first mold and the wall body is released. The first molding is performed with the wall body advancing and retracting means for retracting the wall body and the first mold and the second mold being clamped while leaving the first member on one mold side. A second synthetic resin is injected into the cavity formed by the surface and the second molding surface, and the second member is Characterized in that and a second injection unit for molding the first member and integrally in I.

  According to the present invention, the first member that is a part of the injection-molded body is molded by the first mold and the wall body, and the second member that is the other part is molded by the first mold and the second mold. Perform by mold. That is, a pair of molds is sufficient, and two members can be integrally formed by moving only the wall body, so that the apparatus can be enlarged and the molding time can be shortened. Further, since the first molded body and the second molded body are molded separately, there is no problem that the interface shape is not stable.

  Next, in the above-described injection molding body molding method and injection molding apparatus, the first metal mold and the second metal mold are clamped so that the first metal mold is pressed against the wall body. Can be done. By comprising in this way, the press-contact to the wall body of a 1st metal mold | die can be performed stably, and the operation | movement of mold clamping / die opening with a 1st metal mold | die and a 2nd metal mold | die is utilized. Since the first die can be pressed against the wall, the apparatus can be enlarged and the molding time can be shortened.

  Embodiments of the present invention will be described below. FIG. 1 is a schematic view showing the configuration of the injection molding apparatus 1. The injection molding apparatus 1 is roughly divided into a mold clamping unit 12 for opening and closing the mold 14, a first injection unit 42 and a second injection unit 26 for injecting different types of synthetic resins, and an open state. It is comprised by the wall body advancing / retreating unit 9 which can insert a wall body between the metal mold | die 14 of this.

  First, the mold clamping unit 12 will be described. The mold 14 includes a first mold 14a and a second mold 14b, at least one of which is a movable mold. In the present embodiment, the first mold 14a is a movable mold, and the second mold 14b is a fixed mold. The second mold 14 b is attached to a platen 18 that is disposed at a substantially intermediate position of the frame 10. The first mold 14 a is attached to a mold clamping plate 20 that reciprocates as the ball screw 22 rotates. By the movement of the mold clamping plate 20, the first mold 14a approaches the second mold 14b and is clamped, or is separated from the second mold 14b and the mold is opened. That is, the first mold 14a is movable only in one axial direction for performing mold clamping and mold opening. There are two ball screws 22, for example, one at a diagonal position of the clamping plate 20, and the rotation of a motor (not shown) is transmitted to a pulley 24 fixed to one end of each ball screw 22 to synchronize with each other. Rotate.

  Next, the first injection unit 42 and the second injection unit 26 will be described. In the present embodiment, polypropylene (PP) is injected from the second injection unit 26 as the first synthetic resin B injected from the first injection unit 42 in order to form the hole plug 60 described later. An elastomer resin is used as the synthetic resin A.

  The barrel 44 of the first injection unit 42 is attached to the mold clamping plate 20, and the base end portion of the plunger 48 is fixed to the injection plate 46 that reciprocates by the rotation of the ball screw 50. The barrel 44 is supplied with a molten polypropylene resin material B from a plunger-type plasticizing mechanism 52. A chip-like resin material is fed into the plasticizing mechanism 52 from an upper hopper 54.

  The barrel 28 of the second injection unit 26 is attached to the platen 18, and the base end portion of the plunger 32 is fixed to the injection plate 30 that reciprocates by the rotation of the ball screw 34. In addition, a fixed amount of elastomer resin material A is supplied in a molten state into the barrel 28 from a screw-type quantitative plasticizing mechanism 38 at a time. A chip-like resin material is fed into the quantitative plasticizing mechanism 38 from the hopper 40 at the top thereof.

  There are two ball screws 34 and 50 in the injection units 26 and 42, for example, one at a diagonal position of the injection plates 30 and 46, and a motor is connected to pulleys 36 and 51 fixed to one end of these. (Not shown) rotation is transmitted.

  In addition, at least a portion of the barrels 28 and 44 in the injection units 26 and 42 that receives the resin materials A and B and the tip of the nozzle is heated by an electric heater or the like. Thus, the resin materials A and B until they are filled in the cavity by both the injection units 26 and 42 are kept in a molten state.

  Next, the wall body advancing / retreating unit will be described. The wall body 9 includes a plurality of wall portions 91 and 92 configured to be movable back and forth in a direction orthogonal to the clamping direction of the first mold 14a and the second mold 14b by an actuator 95 such as an air cylinder or a hydraulic cylinder. Consists of. The wall body 9 can be inserted between the first mold 14a and the second mold 14b, and is disposed at a position sandwiched between the molds as described later. Specifically, the wall body advancing / retreating unit opens and closes at positions where the wall portions 91 and 92 constituting the wall body 9 are adjacent to the side having the second forming surface 82 of the second mold 14b. It is configured.

  As shown in the enlarged views of FIGS. 2 and 3, the mold 14 is such that the tip nozzle of the barrel 44 in the first injection unit 42 passes through the first mold 14a and communicates with the first molding surface 81 through the gate 16a. Similarly, the tip nozzle of the barrel 28 in the second injection unit 26 also passes through the second mold 14b and communicates with the second molding surface 16b through the gate 16b. That is, both the injection units 26 and 42 can directly inject the resin materials A and B to the cavities through the individual gates 16a and 16b. Thus, by directly injecting the resin materials A and B from the injection units 26 and 42 through the individual gates 16a and 16b into the cavity, the runners and sprues in the conventional injection molding can be eliminated. As a result, wasteful consumption of the resin material that solidifies while being filled in these runners and sprues can be avoided, and the trouble of removing this resin each time the mold is opened becomes unnecessary.

  The detailed function of the above injection molding apparatus 1 will be described together with an embodiment of the method for molding an injection molded body of the present invention. 2 and 3 are enlarged views of the first mold 14a, the second mold 14b, and the wall bodies 91 and 92 of the injection molding apparatus 1 of FIG. 1, and are diagrams sequentially illustrating the molding process.

(First injection process)
First, as shown in Step 1 of FIG. 2, the side having the first molding surface 81 of the first mold 14 a is pressed against the wall body 9, and the cavity C <b> 1 is formed by the first molding surface 81 and the wall surface of the wall body 9. To do. The pressure contact of the first mold 14 a to the wall body 9 is performed by clamping the first mold 14 a and the second mold 14 b so as to sandwich the wall body 9. Specifically, by driving control of the mold clamping unit 12 shown in FIG. 1, the mold clamping plate 20 and the first mold 14a are moved toward the platen 18, and the wall body 9 is pressed against the second mold 14b side. Weld with pressure. The first injection unit 42 also moves with the mold clamping plate 20.

  Then, as shown in step 2, the first member 64 is molded by injecting the PP resin material B into the cavity C <b> 1 constituted by the first molding surface 81 and the wall surface of the wall body 9. In the present embodiment, the first member 64 becomes the fitting portion 64 of the hole plug 60 of FIG. Specifically, a fixed amount of PP resin material B supplied from the plasticizing mechanism 52 to the barrel 44 is directly injected from the gate 16a into the cavity C1 by the first injection unit 42 shown in FIG.

(Wall evacuation process)
Next, after a predetermined cooling step, the pressure contact between the first mold 14a and the wall body 9 is released as shown in step 3 of FIG. The pressure contact can be released by moving the first mold 14a by a certain amount in the mold opening direction, that is, by moving the first mold 14a together with the mold clamping plate 20 by a certain amount in the direction away from the platen 18. Alternatively, the clamping force applied by the clamping unit 12 may be simply removed. When the pressure contact is released, the first member 64 is held on the first mold 14 a side and peeled off from the wall body 9.

  Then, the wall body 9 is retracted by the actuator 95 of FIG. Retraction of the wall body 9 is performed in a direction in which the first mold 14a is pressed against the wall body 9, that is, a direction orthogonal to the mold clamping direction. Specifically, the plurality of wall portions 91 and 92 constituting the wall body 9 are retracted in directions away from between the first mold 14a and the second mold 14b. That is, the plurality of wall portions 91 and 92 are configured to be movable by the actuator 95 so as to open and close between the first mold 14a and the second mold 14b.

(Second injection process)
Next, as shown in step 4 of FIG. 3, the first mold 14a is moved and directly clamped with the second mold 14b. Similarly to the above, this is performed by moving the mold clamping plate 20 and the first mold 14a toward the platen 18 by the drive control of the mold clamping unit 12 shown in FIG. A cavity C2 is configured by the first molding surface 81 and the second mold 14b by clamping the first mold 14a and the second mold 14b. In the cavity C2, the first member 64 molded in step 2 is held on the first mold 14a side.

  Then, as shown in step 5, the second injection unit 26 directly injects a predetermined amount of the elastomer resin material A supplied from the quantitative plasticizing mechanism 38 to the barrel 28 into the cavity C2 from the gate 16a, The two members 62 are formed integrally with the first member 64. In the present embodiment, the second member 62 serves as the seal portion 62 of the hole plug 60 shown in FIG. 4, whereby an injection molded body (hole plug) 60 is formed in the cavity C2.

  When the above injection molding is completed, after passing through a predetermined cooling process, the mold 14 is opened by the mold clamping unit 12, and the injection molded body 60 is taken out by an ejector pin or the like (not shown). Also in this mold opening, the first mold 14a moves together with the mold clamping plate 20 in the direction away from the platen 18, and the injection unit 42 also moves with the mold clamping plate 20.

  FIG. 4 shows a cross-sectional view of an example of an injection molded body 60 obtained by the molding method. This is a hole plug 60 for sealing a through-hole or the like formed in a body of an automobile or the like, and includes a dish-shaped seal portion 62 and a fitting portion 64 located on the back side thereof. . In the hole plug 60, the seal portion 62 is made of a flexible elastomer resin, and the fitting portion 64 is made of rigid polypropylene (PP). The hole plug 60 is held by inserting the fitting portion 64 into the target hole, and the hole is sealed by bringing the seal portion 62 into close contact with the body surface.

Schematic showing the configuration of an injection molding device Diagram showing manufacturing process using injection molding equipment Figure following Figure 2 Diagram showing injection-molded body obtained by injection molding equipment

Explanation of symbols

1 Injection molding device 14 Mold 14a First mold (movable mold)
14b Second mold (fixed mold)
81 First Molding Surface 82 Second Molding Surface 42 First Injection Unit 26 Second Injection Unit 9 Wall 12 Clamping Unit

Claims (9)

A method of molding an injection molded body in which members made of different types of synthetic resins are integrally molded,
A first mold having a first molding surface is pressed against a wall body, and a first synthetic resin is injected into a cavity constituted by the first molding surface and the wall surface of the wall body to mold a first member. A first injection process;
A wall body retracting step of releasing the pressure contact between the first mold and the wall body and retracting the wall body while leaving the first member on the first mold side;
The first mold and the second mold having the second molding surface are clamped, and a second synthetic resin is injected into a cavity constituted by the first molding surface and the second molding surface, A second injection step of integrally molding a second member with the first member in the cavity;
A molding method of an injection molded body characterized by performing the steps in this order.   In the first injection step, the press contact of the first mold to the wall body is performed by clamping the first mold and the second mold so as to sandwich the wall body. The method for molding an injection-molded article according to claim 1, wherein An injection molding apparatus capable of obtaining an injection molded body in which members made of different types of synthetic resins are integrally molded,
A first mold having a first molding surface, a second mold having a second forming surface, and a wall,
In a state where the first mold is pressed against the wall body, a first synthetic resin is injected into a cavity constituted by the first molding surface and the wall surface of the wall body to mold the first member. A first injection unit;
Wall body advancing / retreating means for retracting the wall body while leaving the first member on the first mold side in a state where the pressure contact between the first mold and the wall body is released;
In a state where the first mold and the second mold are clamped, a second synthetic resin is injected into a cavity constituted by the first molding surface and the second molding surface, and a second member A second injection unit for integrally molding with the first member in the cavity;
An injection molding apparatus comprising:   The pressure contact of the first mold to the wall body is performed by clamping the first mold and the second mold so as to sandwich the wall body. The injection molding apparatus described.   5. The injection according to claim 3, wherein at least one of the first mold and the second mold is a movable mold, and is movable only in one axial direction for performing mold clamping and mold opening. Molding equipment.   6. The injection molding apparatus according to claim 5, wherein the first mold is a movable mold and the second mold is a fixed mold.   The injection molding apparatus according to any one of claims 3 to 6, wherein the wall body is retracted in a direction perpendicular to a direction in which the first mold is pressed against the wall body.   The injection molding apparatus according to any one of claims 3 to 7, wherein the wall body is retracted in a direction orthogonal to a clamping direction of the first mold and the second mold.   The said wall body consists of a some wall part, and each wall part retracts | saves in the direction separated from between the said 1st metal mold | die and the said 2nd metal mold | die. Injection molding equipment.

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