JPH0343225A - Mold for injection molding - Google Patents

Abstract

PURPOSE:To carry out gate cutting and eject by means of a knockout rod, eliminate the necessity of a hydraulic unit for gate cutting and secure the purity of a product by switching between the state of connecting a gate cutting component with the knockout plate side and the cut-off state. CONSTITUTION:A movable side die 10 is brought into close contact with a fixed side mold 12, and molten resin in a cavity 14 is filled from an injection device through a spray 20 and a gate section 22. An electromagnetic actuator 46 is worked to project a plunger 48. The plunger 48 is fixed in a through-hole 50 to move a connecting plate 38 integrally with a knockout plate 24. The knockout plate 26 is moved forward and the knockout plate 24, a driving rod 32, the connecting plate 38 and a gate-cut sleeve 52 are moved to the right to carry out cutting of a gate section 22 of a molded product 16. The knockout plate 24 returns to the initial stopping position to release the connection of the driving rod 32 with the connecting plate 38. After mold opening, the knockout rod 26 is moved to the right, and a sprue knockout pin 34 pushes a sprue section 36.

Description

[Detailed description of the invention] (b) Industrial application field The present invention relates to an injection mold.

(b) Conventional technology When molding a product using an injection molding machine, after the molding is completed in the cavity of the mold, there is a gate cutting operation in which the gate of the molded product is cut while the mold is closed. After opening the mold, an eject operation is required to eject the molded product. Generally, an injection molding machine is equipped with a drive device such as an extraction cylinder for eject operation. However, there is no drive for the gate cut operation, so in the past, a hydraulic cylinder for the gate cut operation was formed inside the mold, or a hydraulic cylinder for the gate cut operation was installed on the movable platen of the injection molding machine. A drive device for gate cutting was constructed by providing a drive device for gate cutting.

(c) Problems to be Solved by the Invention As mentioned above, conventionally, it has been necessary to provide a hydraulic cylinder for gate cutting operation in a mold or an injection molding machine, and also to be equipped with a hydraulic control device to control this. However, the equipment was complicated. In addition, especially in the case of electric injection molding machines, there is a problem in that they do not have a hydraulic power source and therefore require a special hydraulic unit for the gate cutting operation. Although electric injection molding machines have the advantage of being able to mold clean molded products because they do not use hydraulic equipment, it is not desirable to use hydraulic equipment for gate cutting operations. be. The present invention aims to solve these problems.

(d) i! Means for Solving Ill The present invention solves the above problems by also enabling a gate cutting operation by means of a protruding rod for the eject operation of an injection molding machine. That is, in the injection mold according to the present invention,
The movable mold (10) has a protruding plate (24), a spool-protruding bottle (34), and a gate cut member (52).
, product protrusion member (5B), and connection state switching mechanism (5B)
1), and the protrusion plate disposed on the farthest side from the cavity (14) is movable in the direction of the cavity by being pushed by the protrusion rod (26) of the injection molding machine, and is moved by a spring (28). The molded product (16
) The sprue protrusion pin facing the sprue part (36) is connected to the protrusion plate so as to constantly move together, and by moving toward the molded product, the gate part (22) of the molded product can be cut. The cut member is configured so that it can be switched between a state in which it moves in the axial direction together with the protrusion plate and a state in which it is separated from the protrusion plate, and a state in which it moves in the axial direction on the outer circumferential side of the gate cut member. The movably provided product ejecting member is configured to receive a pressing force after the ejecting plate has moved a predetermined amount from the initial stop position toward the cavity.

Note that the symbols in parentheses indicate corresponding members in the embodiments described later.

(Main) Operation In the case of gate cutting operation, the connection state switching mechanism is operated to the connection state side to connect the protrusion plate and the gate cut member. When the protruding plate is advanced toward the cavity in this state, the gate portion of the molded product is cut by the gate cutting member. Next, when performing an eject operation after the movable mold is moved back and the mold is opened, the connection state switching mechanism is operated to the disconnecting side and the ejecting plate is advanced toward the cavity. As a result, the sprue portion is first ejected by the sprue ejector bin, and then, after the ejector plate moves forward by a predetermined amount, the product ejector member starts moving forward, and the product is ejected.

(F) Embodiment FIG. 1 shows an embodiment of the present invention. The injection mold includes a movable mold 10 and a fixed mold 12.

A cavity 14 is formed in the mating surfaces of the movable mold 10 and the fixed mold 12, and thereby a disk-shaped molded product 16 can be molded. The molten resin is filled into the cavity 14 through the gate portion 22 from the sprue 20 at the center of the sprue bush 18 provided at the center of the stationary mold 12 side. Note that the sprue bush 18 is movable in the axial direction. A protrusion plate 24 is provided on the farthest side from the cavity 14 of the movable mold 10 so as to be movable in the axial direction. The ejector plate 24 moves to the right when the ejector rod 26 of the injection molding machine moves to the right in FIG. A spring 28 is provided on the protrusion plate 24 to apply a force counteracting the force from the protrusion rod 26. When the protrusion rod 26 retreats, the force of the spring 28 causes the protrusion plate 24 to reach the initial stop position where it contacts the stopper 29. (Note that a mold mounting plate (not shown) for mounting the movable mold 10 on a movable platen (not shown) may be used as the stopper 29). Further, a limit switch 30 is provided that can detect that the protruding plate 24 is at the initial stop position. A driving rod 3 is installed in the center of the protruding plate 24.
2 is fixed to the drive rod 32, and a sprue protruding pin 34 is further provided on the distal end side of the drive rod 32. Note that the drive rod 32 and the sprue protrusion pin 34 are integrally constructed. The tip of the sprue ejecting pin 34 extends to a position where it comes into contact with the sprue portion 36 of the molded product 16. The drive rod 32 passes through a hole 40 in the coupling plate 38. The connecting plate 38 is supported by the movable mold 10 so as to be movable in the axial direction, and is pressed by a spring 42 to an initial stop position where it contacts a stopper 44 . An electromagnetic actuator 46 is provided on the coupling plate 38, and this electromagnetic actuator 46 is connected to the plunger 4.
8 can be projected toward the center of the hole 40. This part is shown enlarged in FIG. The drive rod 32 is provided with a plunger through hole 50 having a diameter somewhat larger than the outer diameter of the plunger 48. Connection plate 3
8 and the protruding plate 24 are at the initial stop position, the position of the plunger 48 and the position of the through hole 50 are arranged to coincide. Therefore, when the electromagnetic actuator 46 is operated in this state to cause the plunger 48 to protrude, the plunger 48 fits into the through hole 5o. In this state, the connecting plate 38 is connected to the protruding plate 2.
4 in the axial direction. The above-mentioned connecting plate 38, electromagnetic actuator 46, and drive rod 3
The two through holes 50 and the like constitute a connection state switching mechanism 51. A hollow gate cut sleeve 52 is provided integrally with the connecting plate 38. The edge-shaped tip of the gate cut sleeve 52 faces the gate portion 22 of the molded product 16. As shown in FIG. 3, the gate cut sleeve 52 is provided with an elongated hole 54 in the axial direction.
A push rod 56, which will be described later, passes through this.

The push rod 56 is fixed to the drive rod 32 in a direction perpendicular thereto. A product ejection sleeve 58 is provided on the outer periphery of the gate cut sleeve 52. The right end surface of the product ejection sleeve 58 in FIG. 1 is arranged so as to be in contact with the molded product 16, while the left end surface is arranged so as to overlap the elongated hole 54 by a predetermined amount in the axial direction. Also,
The product ejecting sleeve 58 is provided with a flange portion 58a, on which a spring 59 applies a returning force toward the left in FIG.

Next, the operation of this embodiment will be explained. First, a mold closing process is performed in which the movable mold 10 is brought into close contact with the fixed mold 12 and a predetermined mold clamping force is applied.Then, an injection device (not shown) passes the spuffle 20 and the gate part 22 into the cavity. 14 is filled with molten resin. After holding pressure in this state for a predetermined period of time, the cooling process is started. Simultaneously with the start of the cooling process, the electromagnetic actuator 46 is actuated to cause the plunger 48 to protrude. The plunger 48 fits into the through hole 50, and the connecting plate 38 becomes movable in the axial direction together with the protruding plate 24. The ejector rod 26 then moves forward, moving the ejector plate 24 to the right in FIG. As a result, the protruding plate 24, the driving rod 32, the connecting plate 38, and the gate cutting sleeve 52 are moved rightward together, and the gate portion 22 of the molded product 16 is cut. As the gate cut sleeve 52 moves to the right, the sprue bush 18 also moves by the same distance. Note that the amount of movement in this case is 71 d until the connecting plate 38 is stopped, and this dimension d is the distance between the gate portion 22
is set to a size that can be cut. Note that the product ejecting sleeve 58 does not move during the above operation.

This is because when the connecting plate 38 is moved by the distance d, the push rod 56 does not reach the position 4 where it comes into contact with the product ejecting sleeve 58. Immediately before the end of the cooling process, the ejector rod 26 is retracted. As a result, the force of the springs 28 and 42 causes the ejection plate 24, drive rod 32, connection plate 38, gate cut sleeve 52, sprue ejection pin 34 and sprue bush 1 to
8 returns to the initial stop position. This is detected by limit switch 30. At the same time, the electromagnetic actuator 46 operates to pull in the plunger 48. As a result, the drive rod 32 and the connecting plate 38
The connection state with is canceled. After the cooling process is completed, a mold opening process is performed next. That is, the movable mold 10
moves to the left in FIG. After opening the mold, the ejector rod 26 moves to the right in the first case again.

Along with this, the ejector plate 24 also moves to the right in FIG. Only the push rod 34 and the push rod 56 move to the right. Since the tip of the sprue ejecting pin 34 pushes the sprue portion 36, this causes the sprue portion 36 to
The protrusion is performed. Next, when the drive rod 32 moves further forward, the push rod 56 comes into contact with the left end surface of the product ejecting sleeve 58 in FIG. 1, and moves it to the right. As a result, the product (the molded product 16 with the sprue portion 36 removed) is ejected. After ejecting the product, when the ejector rod 26 retreats, the ejector plate 24 and the member integral therewith are returned to the initial position by the spring 28, and the product ejector sleeve 58
is returned to its initial position by a spring 59.

In this embodiment, the limit switch 30 is used to detect that the ejector plate 24 is at the initial setting position, but any of the ejector plate 24, drive rod 32, sprue ejector pin 34, push rod 56, and ejector rod 26 Alternatively, one member may be provided with a position detection potentiometer or encoder.

(G) As described in detail, according to the present invention, the connection state switching mechanism enables switching between the state in which the gate cutting member is protruded and connected to the plate side, and the state in which it is separated. It becomes possible to perform both the gate cutting operation and the ejecting operation using the ejecting rod of the molding machine, and there is no need to provide a dedicated hydraulic device for the gate cutting operation. Particularly in the case of an electric injection molding machine that is not equipped with a hydraulic power source, a hydraulic unit for gate cutting is not required, and since hydraulic pressure is not used, it is advantageous in ensuring the cleanliness of the product.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is an enlarged view of the connection state switching mechanism, and FIG. 3 is a perspective view showing an elongated portion. 10... Movable side mold, 12. ・Fixed side mold, 14.
...Cavity, 16...Molded product, 22...Gate part, 24...Protrusion plate, 26...Protrusion rod, 28...Spring, 32...Drive rod, 3
4... Sprue ejection pin, 36... Sprue part,
38...Connection plate, 46...Mf, Vii actuator, 48...Plunger 50...Through hole, 51...Connection state switching mechanism, 52
...Gate cut sleeve, 54...Elongated hole, 56.
...Push rod, 58...Sleeve for ejecting the product.

Claims (1)

[Scope of Claims] In an injection mold consisting of a fixed side mold and a movable side mold, the movable side mold includes an ejector plate, a sprue ejector pin,
A gate cutting member, a product ejecting member, and a connection state switching mechanism are provided, and the ejecting plate disposed on the farthest side from the cavity is movable in the direction of the cavity by being pushed by the ejecting rod of the injection molding machine. The sprue ejector pin, which is pressed in the direction away from the cavity by a spring and faces the sprue of the molded product, is connected to the ejector plate so that it always moves together with the molded product. The gate cutting member, which can cut the gate part, is configured so that it can be switched between a state in which it moves in the axial direction together with the protrusion plate and a state in which it is separated from the protrusion plate, using a connection state switching mechanism. The product protruding member provided movably in the axial direction on the outer circumferential side of the member is characterized in that it is configured to receive a pressing force from this after the protruding plate has moved a predetermined amount from the initial stop position toward the cavity side. Mold for injection molding.