Injection molding die

Abstract

To provide an injection molding die that is simple in configuration and does not require gate cutting by secondary processing.SOLUTION: The injection molding die has a punch motion mechanism. The punch motion mechanism has: a cam driver extending in a first direction; a first cam operated in a direction intersecting the first direction when the cam driver contacts it; and a second cam provided integral with a punch portion and operated in a second direction opposite the first direction when the first cam contacts it. When the first cam is operated by the cam driver along with the die opening between a second plate and a third plate, a runner portion formed on a sprue portion is punched out by the punch portion in conjunction with the second cam.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a mold for injection molding.

Background Art

[0002] Conventionally, in a direct gate structure of an injection mold having a plurality of plates, it was common for the molded product and the runner to be taken out integrally after injection molding. Therefore, after taking out the molded product from the mold, gate cutting was required in secondary processing.

[0003] On the other hand, for example, Patent Document 1 discloses a technique in which a molded product and a runner are separated and taken out after injection molding. According to this document, a punch pin is provided in the mold, and after injection molding an optical disk, the sprue portion of the optical disk is punched out with the punch pin. As the power for pushing out the punch pin, it is stated that a dedicated motor or a ball screw mechanism is used.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the technique of Patent Document 1, a dedicated motor and a ball screw must be attached to the mold, and a control unit and electrical wiring for driving the motor at an optimal timing are also required, which not only complicates the configuration but also imposes a control burden on the injection molding machine side. That is, there has been a demand for an injection mold with a simple configuration that does not require gate cutting by secondary processing.

Means for Solving the Problems

[0006] The injection mold according to one aspect of the present application includes a first plate having a first mold surface for molding a molded product, a sprue bush portion provided in the first plate for injecting a molding material in a first direction through a sprue portion, a second plate having a second mold surface facing the first mold surface, forming a cavity between the first mold surface and the second mold surface, and including a punch portion, and a third plate disposed on the side of the second plate opposite to the first plate and including a punch operating mechanism for operating the punch portion. The punch operating mechanism includes a cam driver extending in the first direction, a first cam that operates in a direction intersecting the first direction when the cam driver abuts, and a second cam provided integrally with the punch portion and operating in a second direction opposite to the first direction when the first cam abuts. When the first cam is operated by the cam driver with the mold opening between the second plate and the third plate, the runner portion formed in the sprue portion is punched by the punch portion interlocking with the second cam.

Brief Description of the Drawings

[0007]

Figure 1

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Figure 13

Mode for Carrying Out the Invention

[0008] Embodiment 1 ***Outline of an injection mold*** FIG. 1 is a cross-sectional view of an important part of the mold according to this embodiment. FIG. 2 is a perspective view of the molded product.

[0009] The mold 100 shown in FIG. 1 is an injection mold, and injection molding is performed in a state of being set in an injection molding apparatus 200 (not shown). The injection molding apparatus 200 includes a plasticizing apparatus 150 that plasticizes a material containing resin to generate a molding material and injects it into the mold 100 from a nozzle 70, and a clamping apparatus (not shown) that clamps and opens the mold 100.

[0010] The plasticizing apparatus 150 may be any apparatus that can inject the plasticized molding material. For example, a screw-type plasticizing apparatus can be used. Further, from the viewpoint of miniaturization, a small plasticizing apparatus including a disk-shaped flat screw formed with spiral grooves and a barrel facing the flat screw and having a communication hole at the center may be used as the plasticizing apparatus 150. The clamping apparatus (not shown) includes a motor, a speed reducer, a ball screw mechanism, etc., and controls the clamping and opening operations of the mold 100. For ease of explanation, in each figure, an important part of the mold 100 and the nozzle 70 of the plasticizing apparatus 150 are excerpted and shown.

[0011] As shown in FIG. 1, the mold 100 is composed of a first plate 10, a second plate 20, a third plate 30, etc. At the time of clamping, the first plate 10, the second plate 20, and the third plate 30 are in close contact and integrated. At the time of clamping, the mold 100 has a rectangular parallelepiped shape.

[0012] In each figure, the X-axis, Y-axis, and Z-axis are illustrated as three axes orthogonal to each other. In the present embodiment, the stacking direction of the three plates is the +Z direction. The +Z direction is the direction in which the molding material is injected from the nozzle 70 into the mold 100, and is also referred to as the first direction. The -Z direction is also referred to as the second direction. The width direction of the mold 100 is the +Y direction, and the depth direction of the mold 100 is the +X direction. The +Z direction and the -Z direction together are also referred to as the Z-axis direction. The same applies to the X-axis and Y-axis. Along the Z-axis direction, the line segment passing through the tip of the nozzle 70 and the punch portion 50 is defined as the center line 60. In the actual mold configuration, a fixed-side mounting plate is provided in the -Z direction of the first plate 10 of the mold 100, and a receiving plate, spacers, a movable-side mounting plate, etc. are provided in the +Z direction of the third plate 30, but the illustration thereof is omitted.

[0013] In a preferred example, the first plate 10 is made of alloy tool steel, but it is not limited thereto, and any hard metal such as steel, other metals, or alloys may be used. The same applies to the materials of the second plate 20, the third plate 30, the punch portion 50, the cam portion, etc. The first plate 10 includes a sprue bush portion 12, a first mold surface 11, etc. The sprue bush portion 12 includes a sprue portion 14 which is a flow path for injecting the molding material ejected from the nozzle 70 of the plasticizing device 150 into the cavity 22 of the mold 100. In the mold 100, a direct gate for injecting the molding material directly from the sprue portion 14 into the cavity 22 is adopted. The details of the sprue bush portion 12 will be described later. The first mold surface 11 is the molding surface of the first plate 10. The first mold surface 11 forms the cavity 22 facing the second mold surface 21 of the second plate 20 during mold clamping.

[0014] Figure 2 is a perspective view of the molded product 1 formed within the cavity 22. The molded product 1 is, for example, a disk-shaped part. The molded product 1 has a through-hole at its center in the completed state, but at the time of molding, as shown in Figure 2, a rod-shaped runner part 2 protrudes from the portion that will become the through-hole. The runner part 2 is a part where the molding material within the sprue part 14 of the sprue bush part 12 has hardened, and at the time of molding, it is integrated with the molded product 1. Usually, in the case of such a direct gate structure, after the molded product 1 is taken out, it was necessary to perform a gate cut to remove the runner part 2 by secondary processing. However, according to the mold 100 of the present embodiment, by the punch operation mechanism 80 described later, at the time of taking out the molded product, the molded product 1 and the runner part 2 can be taken out in a separated state. Note that the molded product 1 is not limited to a disk-shaped part, and any part that can be formed with a direct gate is acceptable. The second plate 20 includes a second mold surface 21 and a through-hole 23 through which the punch part 50 is inserted along the center line 60.

[0015] Figure 3 is an enlarged view of part c in Figure 1. As shown in Figure 3, the sprue bush part 12 is composed of a base part 18, bolts 16, a cylinder part 13, an elastic member 17, and the like. The base part 18 is a disk-shaped base member and has a concave part 19 that abuts against the nozzle 70. The base part 18 is fixed to the first plate 10 by a plurality of bolts 16 at its peripheral edge. The bolts 16 are, in a preferred example, shoulder bolts, and fix the sprue bush part 12 to be movable within a certain range in the Z-axis direction. Note that guide pins may be used instead of the bolts. The cylinder part 13 extends in the +Z direction from the center part of the base part 18. The inside of the cylinder part 13 forms the sprue part 14 and communicates with the concave part 19.

[0016] At the root part of the cylinder part 13 in the -Z direction, an elastic member 17 is provided. In a preferred example, the elastic member 17 is a coil spring. As shown in FIG. 3, at the time of mold clamping, the nozzle 70 abuts against the concave part 19, and since the base part 18 is pressed in the +Z direction, the space between the base part 18 and the first plate 10 is in close contact. At this time, the elastic member 17 is in a compressed state. In other words, the sprue bush part 12 has the elastic member 17. Note that the elastic member 17 is not limited to a coil spring, and any member having elasticity may be used, for example, rubber or an elastomer.

[0017] As shown in FIG. 3, the punch part 50 is composed of an anchor pin 7, an Ej sleeve 6, and a punch cylinder 5. The Ej sleeve 6 and the punch cylinder 5 have a cylindrical shape. The anchor pin 7 is a pin having a constricted part 8 at its tip. The Ej sleeve 6 houses the anchor pin 7. The punch cylinder 5 houses the Ej sleeve 6 including the anchor pin 7. The punch part 50 has a triple structure in which the central anchor pin 7 is surrounded concentrically by the Ej sleeve 6 and the punch cylinder 5. At the time of molding with the mold clamped, the position of the end of the punch cylinder 5 is the same as the position of the second mold surface 21, the position of the end of the anchor pin 7 is on the +Z side from the position of the second mold surface 21, and the position of the end of the Ej sleeve 6 is on the +Z side from the end of the anchor pin 7. The positional relationship of the ends of the three parts constituting the punch part 50 at the time of this molding is referred to as the initial end position.

[0018] In other words, the punch part 50 is composed of an anchor pin 7, an Ej sleeve 6, and a punch cylinder 5. The Ej sleeve 6 and the punch cylinder 5 have a cylindrical shape. The Ej sleeve 6 houses the anchor pin 7, and the punch cylinder 5 houses the Ej sleeve 6 including the anchor pin 7, forming a three-layer structure.

[0019] ***Configuration of the punch operating mechanism*** Return to FIG. 1. The punch operation mechanism 80 is composed of cam drivers 40a, 40b, first cams 41a, 41b, second cam 42, third cams 43a, 43b, fourth cam 44, fifth cam 45, etc. The cam driver 40a and the cam driver 40b are paired members and are in a line-symmetrical relationship with the center line 60 as the axis of symmetry. Similarly, the first cam 41a and the first cam 41b, and the third cams 43a and 43b are also in a line-symmetrical relationship with the center line 60 as the axis of symmetry. Hereinafter, when explaining members in a symmetrical relationship, the branch numbers will be omitted as in the case of the cam driver 40. The same applies to cam members. The punch operation mechanism 80 is mainly provided on the third plate 30, and a part thereof also extends to the peripheral portion of the third plate 30.

[0020] The cam driver 40a extends in the +Z direction along the side surface on the +Y side of the third plate 30. A convex portion 46 protruding toward the center line 60 is provided at the -Z side end of the cam driver 40a. The cam driver 40a moves in the +Z direction along with the mold opening operation between the second plate 20 and the third plate 30. At this time, the convex portion 46 of the cam driver 40a abuts on one end of the first cam 41a, and the first cam 41a is pushed in the direction of the center line 60 and driven. The portions where the convex portion 46 and the first cam 41a abut are tapered with respect to each other.

[0021] The first cam 41a is a cam component extending in the Y-axis direction within the third plate 30. The other end of the first cam 41a abuts on the shoulder portion of the second cam 42. When the first cam 41a moves in the direction of the center line 60, the second cam 42 is pushed in the -Z direction. The second cam 42 is a plate-shaped portion extending in the Y-axis direction, and the punch cylinder 5 is fixed thereto. When the second cam 42 is driven in the Z-axis direction, the punch cylinder 5 also operates integrally. In the above description, the operation on the cam driver 40a side during mold opening has been explained, but the same operation is also performed on the cam driver 40b side. Specifically, when the cam driver 40b moves in the Z plus direction along with the mold opening operation, the first cam 41b is pushed into the direction of the center line 60, and the second cam 42 is driven in the Z minus direction. That is, the second cam 42 is pushed in from two directions by the first cams 41a and 41b along with the mold opening operation and is driven in the Z minus direction.

[0022] The third cam 43a is a cam part similar to the first cam 41a and is arranged on the Z plus side of the first cam 41a in the third plate 30. In FIG. 1, although not shown, the mold 100 is provided with a cam driver similar to the cam driver 40a for driving the third cam 43a. The same applies to the third cam 43b side paired with the third cam 43a. The other end of the third cam 43a abuts against the shoulder of the fourth cam 44, and when the third cam 43a moves in the direction of the center line 60, the fourth cam 44 is pushed into the Z minus direction.

[0023] The fourth cam 44 is a plate-like part similar to the second cam 42 and is arranged on the Z plus side of the second cam 42 in the third plate 30. An anchor pin 7 is fixed to the fourth cam 44. A fifth cam 45 is provided on the Z minus side of the fourth cam 44. The fifth cam 45 is a plate-like part similar to the second cam 42 and is in close contact with the fourth cam 44 during mold clamping. An Ej sleeve 6 is fixed to the fifth cam 45. The fifth cam 45 is also interlocked with an ejector pin operating mechanism (not shown).

[0024] In other words, the mold 100 includes a first plate 10 having a first mold surface 11 for molding the molded product 1, a sprue bush portion 12 provided in the first plate 10 and injecting the molding material in the first direction through the sprue portion 14, a second plate 20 having a second mold surface 21 facing the first mold surface 11, forming a cavity 22 between the first mold surface 11 and the second mold surface 21, and including a punch portion 50, and a third plate 30 disposed on the side of the second plate 20 opposite to the first plate 10 and including a punch operating mechanism 80 for operating the punch portion 50. The punch operating mechanism 80 includes a cam driver 40 extending in the first direction, a first cam 41 that operates in a direction intersecting the first direction when the cam driver 40 abuts, and a second cam 42 that is integrally provided with the punch cylinder 5 of the punch portion 50 and operates in a second direction opposite to the first direction when the first cam 41 abuts.

[0025] ***Mold opening restricting magnet*** As shown in FIG. 1, a first magnet 15a is attached to the end portion on the Y plus side of the first plate 10. The first magnet 15a is arranged with its S pole facing the Z plus side. In a preferred example, the first magnet 15a employs a permanent magnet. A second magnet 25a is attached to the end portion on the Y plus side of the second plate 20. The second magnet 25a is arranged with its N pole facing the Z minus side. In a preferred example, the second magnet 25a employs a permanent magnet. At the time of mold clamping, the first magnet 15a and the second magnet 25a are in contact with each other and attracted.

[0026] A first magnet 15b paired with the first magnet 15a is attached to the end portion on the Y minus side of the first plate 10. The first magnet 15b is arranged with its S pole facing the Z plus side. Similarly, a second magnet 25b is attached to the end portion on the Y minus side of the second plate 20. The second magnet 25b is arranged with its N pole facing the Z minus side. At the time of mold clamping, the first magnet 15b and the second magnet 25b are in contact with each other and attracted. That is, during mold clamping, the space between the first plate 10 and the second plate 20 is attracted by the magnetic force of the magnet pairs of the first magnet 15a and the second magnet 25a, and the first magnet 15b and the second magnet 25b. Note that the first magnets 15a and 15b and the second magnets 25a and 25b are not limited to permanent magnets, and any magnet may be used. For example, an electromagnet may be used.

[0027] In other words, the first plate 10 has the first magnets 15a and 15b, the second plate 20 has the second magnets 25a and 25b, and the first magnets 15a and 15b and the second magnets 25a and 25b are arranged to attract each other.

[0028] ***Gate cutting operation*** FIG. 4 is a cross-sectional view of an important part of the mold and corresponds to FIG. 1. FIG. 5 is an enlarged view of the periphery of the molded product in FIG. 4 and corresponds to FIG. 3. Here, the operation of performing gate cutting in the mold 100 after the molded product 1 is formed will be described. First, in the mold-clamped state shown in FIG. 1, the molding material is injected from the nozzle 70, the molded product 1 is formed in the cavity 22, and the runner part 2 is formed in the sprue part 14.

[0029] After the molded product 1 is formed, when a predetermined cooling time has elapsed, the nozzle 70 retracts in the Z minus direction. When the nozzle 70 retracts, the pressing force by the nozzle 70 disappears, so the sprue bush part 12 also retracts in the Z minus direction due to the spring force of the elastic member 17 that has been compressed. As a result, as shown in FIG. 5, the cylinder part 13 moves in the Z minus direction, and the guide hole 33 is exposed. The guide hole 33 is a through hole through which the cylinder part 13 is inserted, but during gate cutting, it becomes a receiving hole into which the tip of the punch part 50 enters. In other words, before punching by the punch part 50, the sprue bush part 12 retracts in the second direction due to the spring force of the elastic member 17.

[0030] FIG. 6 is a cross-sectional view of a main part of the mold, corresponding to FIG. 4. FIG. 6 shows the initial state of mold opening. FIG. 7 is an enlarged view of the periphery of the molded product in FIG. 6, corresponding to FIG. 5. As shown in FIG. 6, mold opening starts between the second plate 20 and the third plate 30. At this time, between the first plate 10 and the second plate 20, it is closed by the attracting forces of the first magnet 15a and the second magnet 25a, and the first magnet 15b and the second magnet 25b.

[0031] With the mold opening between the second plate 20 and the third plate 30, the cam driver 40a moves in the +Z direction. At this time, the convex portion 46 of the cam driver 40a abuts against one end of the first cam 41a, and the first cam 41a is pushed in the direction of the center line 60. As a result, as indicated by the arrow, the second cam 42 is driven in the -Z direction by the other end of the first cam 41a. Also, the same operation is performed on the side of the cam driver 40b. Specifically, with the movement of the cam driver 40b in the +Z direction, the first cam 41b is pushed in the direction of the center line 60, and the second cam 42 is driven in the -Z direction by the other end of the first cam 41b.

[0032] Also, in conjunction with the movement of the first cams 41a, 41b, the third cams 43a, 43b are also pushed in the direction of the center line 60, and together drive the fourth cam 44 and the fifth cam 45 in the -Z direction. Note that the third cams 43a, 43b are driven by a pair of cam drivers (not shown) similar to the cam drivers 40a, 40b.

[0033] As a result, as shown in FIG. 7, the punch portion 50 is driven into the guide hole 33 of the first plate 10 while keeping the end positions of the three portions as the initial end positions. At this time, the punch cylinder 5 functions as a punch die and punches the center of the molded product 1. This is also called gate cutting. The punched runner portion 2 is held by the punch portion 50 and fits into the guide hole 33 and the sprue portion 14. In other words, when the first cam 41 operates by the cam driver 40 as the mold opens between the second plate 20 and the third plate 30, the runner portion 2 formed in the sprue portion 14 is punched out by the punch portion 50 interlocked with the second cam 42.

[0034] ***Ejecting operation*** FIG. 8 is a cross-sectional view of a main part of the mold in one aspect and corresponds to FIG. 6. FIG. 9 is an enlarged view of the periphery of the molded product in FIG. 8 and corresponds to FIG. 7. FIG. 8 shows a state where the mold opening has advanced further than in FIG. 6. As the mold opening between the second plate 20 and the third plate 30 progresses, the cam driver 40a further moves in the Z plus direction, and as shown in FIG. 8, the convex portion 46 disengages from the first cam 41a. Note that the Z plus side at one end of the first cam 41a has a notch shape, and the configuration is such that the passage of the convex portion 46 is smooth. Thereby, the first cam 41a moves in a direction away from the center line 60 as indicated by the arrow. Note that similar notch shapes are also provided for the first cam 41b and the third cams 43a and 43b.

[0035] Also, the same operation is performed on the cam driver 40b side. Specifically, when the cam driver 40b further moves in the Z plus direction and the convex portion 46 disengages from the first cam 41b, the first cam 41b moves in a direction away from the center line 60. Then, the second cam 42 is released from the pressing by the first cams 41a and 41b and moves in the Z plus direction as indicated by the arrow. At this time, the third cams 43a and 43b are not driven, and the positions of the fourth cam 44 and the fifth cam 45 do not change.

[0036] This state is shown in FIG. 9. As the second cam 42 moves, only the punch cylinder 5 retreats in the Z plus direction as indicated by the arrow. Thereby, the end portion of the runner portion 2 is in a state of being engaged only with the constricted portion 8 of the anchor pin 7. In other words, the anchor pin 7 holds the runner portion 2 punched out by the punch portion 50 with the constricted portion 8.

[0037] FIG. 10 is a cross-sectional view of a main part of the mold and corresponds to FIG. 8. FIG. 11 is an enlarged view of the periphery of the molded product in FIG. 10 and corresponds to FIG. 9. FIG. 10 shows a state where the mold opening has advanced more than in FIG. 8. When the mold opening further advances, the mold opening force exceeds the attracting forces by the first magnet 15a and the second magnet 25a, and by the first magnet 15b and the second magnet 25b, and the mold opening between the first plate 10 and the second plate 20 starts. In other words, the attracting forces by the first magnet 15a and the second magnet 25a, and by the first magnet 15b and the second magnet 25b are set to the attracting forces at which the mold opening starts at this timing. Therefore, due to the attracting forces, after the mold opening between the second plate 20 and the third plate 30, the mold opening between the first plate 10 and the second plate 20 is performed. This state is shown in FIG. 10, and the molded product 1 and the runner part 2 are exposed to the outside in a state of being attached to the second plate 20 side. The end of the runner part 2 is still located in the guide hole 33 of the first plate 10. As shown in FIG. 11, the molded product 1 is in close contact with the second mold surface 21 of the second plate 20. The runner part 2 is held in a state of being fitted to the constricted part 8 of the anchor pin 7.

[0038] FIG. 12 is a cross-sectional view of a main part of the mold and corresponds to FIG. 10. FIG. 13 is an enlarged view of the periphery of the molded product in FIG. 12 and corresponds to FIG. 11. FIG. 12 shows a state where the mold opening has advanced more than in FIG. 10 and the mold opening is completed. When the mold opening further advances, the space between the first plate 10 and the second plate 20 expands, all of the runner part 2 is exposed, and the molded product 1 and the runner part 2 can be taken out.

[0039] When the mold opening is completed, the ejector pin operating mechanism (not shown) performs the operation of taking out the molded product 1. Specifically, as shown in FIG. 13, the ejector pins 62a and 62b protrude in the negative Z direction from the second mold surface 21 of the second plate 20 to push out the molded product 1. At this time, in conjunction with the operation of the ejector pins 62a and 62b, as shown in FIG. 12, the fifth cam 45 is driven in the negative Z direction. At this time, in the punch portion 50, only the Ej sleeve 6 protrudes in the negative Z direction in conjunction with the fifth cam 45. In other words, with the runner portion 2 held by the anchor pin 7, after the punch cylinder 5 retreats in the first direction, the Ej sleeve 6 moves in the second direction, and the runner portion 2 is removed from the constricted portion 8. Then, the Ej sleeve 6 is driven in conjunction with the ejector pins 62a and 62b of the molded product 1 formed in the cavity 22.

[0040] As a result, as shown in FIG. 13, the molded product 1 and the runner portion 2 are taken out together from the second plate 20 in a separated state. The molded product 1 is released from the second mold surface 21 by the ejector pins 62a and 62b. The runner portion 2 is removed by having the portion engaged with the constricted portion 8 of the anchor pin 7 pushed out by the Ej sleeve 6. In FIG. 13, two ejector pins 62a and 62b are provided at the symmetric positions of the molded product 1 with the center line 60 as the axis of symmetry, but three or more ejector pins may be provided.

[0041] As described above, according to the mold 100 of the present embodiment, the following effects can be obtained. The mold 100 includes a first plate 10 having a first mold surface 11 for molding a molded product 1, a sprue bush portion 12 provided in the first plate 10 and injecting a molding material in a first direction through a sprue portion 14, a second plate 20 having a second mold surface 21 facing the first mold surface 11, forming a cavity 22 between the first mold surface 11 and the second mold surface 21, and including a punch portion 50, and a third plate 30 disposed on the side of the second plate 20 opposite to the first plate 10 and including a punch operating mechanism 80 for operating the punch portion 50. The punch operating mechanism 80 includes a cam driver 40 extending in the first direction, a first cam 41 that operates in a direction intersecting the first direction when the cam driver 40 abuts, and a second cam 42 that is provided integrally with a punch cylinder 5 of the punch portion 50 and operates in a second direction opposite to the first direction when the first cam 41 abuts. With the mold opening between the second plate 20 and the third plate 30, when the first cam 41 is operated by the cam driver 40, the runner portion 2 formed in the sprue portion 14 is punched out by the punch portion 50 interlocked with the second cam 42.

[0042] According to this, by driving the cam driver 40, the first cam 41, and the second cam 42 using the mold opening operation, gate cutting can be performed within the mold 100. In particular, unlike the prior art in which a dedicated motor or a control unit was required to drive a punch pin within the mold, according to the mold 100, a dedicated motor or the like is not required. Therefore, it is possible to provide an injection molding mold 100 with a simple configuration that does not require gate cutting by secondary processing.

[0043] Further, the first plate 10 has first magnets 15a, 15b, the second plate 20 has second magnets 25a, 25b, and the first magnets 15a, 15b and the second magnets 25a, 25b are arranged to adsorb to each other. Due to the adsorption force by this adsorption, after the mold opening between the second plate 20 and the third plate 30, the mold opening between the first plate 10 and the second plate 20 is performed. In a preferred example, the first magnets 15a, 15b and the second magnets 25a, 25b are permanent magnets. According to this, by utilizing the attracting force of a permanent magnet that does not require power, it is possible to regulate the order of mold opening with a simple configuration without the need for a dedicated control unit or the like.

[0044] Further, the sprue bush portion 12 has an elastic member 17, and before punching by the punch portion 50, the sprue bush portion 12 retreats in the second direction due to the spring force of the elastic member 17. According to this, by the retreat of the sprue bush portion 12, a guide hole 33 is prepared in the first plate 10, and the guide hole 33 can be used as a receiving hole into which the tip of the punch portion 50 enters during gate cutting.

[0045] The punch portion 50 is composed of an anchor pin 7, an Ej sleeve 6, and a punch cylinder 5. The Ej sleeve 6 and the punch cylinder 5 are cylindrical, the Ej sleeve 6 houses the anchor pin 7, and the punch cylinder 5 houses the Ej sleeve 6 including the anchor pin 7, forming a three-layer structure. According to this, at the time of gate cutting, the punch portion 50 functions as a punch die integrally with three parts. At the time of the ejecting operation, after the punch cylinder 5 retreats to make it easy to remove the runner portion 2, the runner portion 2 can be pushed out and taken out by the Ej sleeve 6.

[0046] The anchor pin 7 has a constricted portion 8 at its tip, and the anchor pin 7 holds the runner portion 2 punched by the punch portion 50 with the constricted portion 8. According to this, the runner portion 2 can be held by the anchor pin 7 until the runner portion 2 is taken out by the ejecting operation.

[0047] Also, after the punch cylinder 5 retreats in the first direction while the runner portion 2 is held by the anchor pin 7, when the Ej sleeve 6 moves in the second direction, the runner portion 2 is removed from the constricted portion 8. According to this, after holding the runner portion 2 in a state where it can be taken out, the runner portion 2 can be taken out by the Ej sleeve 6 at the ejecting timing.

[0048] Further, the Ej sleeve 6 is driven in conjunction with the ejector pins 62a and 62b of the molded product 1 formed in the cavity 22. According to this, in a state where the molded product 1 and the runner portion 2 are separated, they can be taken out together from the second plate 20. Therefore, it is not necessary to perform gate cutting by secondary processing.

Explanation of Reference Numerals

[0049] 1... Molded product, 2... Runner portion, 5... Punch cylinder, 6... Ej sleeve, 7... Anchor pin, 8... Constriction portion, 10... First plate, 11... First mold surface, 12... Sprue bush portion, 13... Cylinder portion, 14... Sprue portion, 15a... First magnet, 15b... First magnet, 16... Bolt, 17... Elastic member, 18... Base portion, 19... Recess, 20... Second plate, 21... Second mold surface, 22... Cavity, 23... Through hole, 25a... Second magnet, 25b... Second magnet, 30... Third plate, 33... Guide hole, 40... Cam driver, 40a... Cam driver, 40b... Cam driver, 41... First cam, 41a... First cam, 41b... First cam, 42... Second cam, 43a... Third cam, 43b... Third cam, 44... Fourth cam, 45... Fifth cam, 46... Protrusion, 50... Punch portion, 60... Center line, 62a... Ejector pin, 70... Nozzle, 80... Punch operating mechanism, 100... Mold, 150... Plasticizing device, 200... Injection molding device.

Claims

1. A first plate having a first mold surface for molding a molded product, a sprue bush portion provided in the first plate and injecting a molding material in a first direction through a sprue portion, A second plate having a second mold surface facing the first mold surface, forming a cavity between the first mold surface and the second mold surface, and including a punch portion, A third plate disposed on the opposite side of the second plate from the first plate and including a punch operating mechanism for operating the punch portion, The punch operating mechanism includes A cam driver extending in the first direction, A first cam that operates in a direction intersecting the first direction when the cam driver abuts, A second cam provided integrally with the punch portion and operating in a second direction opposite to the first direction when the first cam abuts, When the first cam is operated by the cam driver with the mold opening between the second plate and the third plate, the runner portion formed in the sprue portion is punched by the punch portion interlocked with the second cam, An injection molding die.

2. The first plate has a first magnet, The second plate has a second magnet, The first magnet and the second magnet are arranged to attract each other, Due to the attracting force by the attraction, after the mold opening between the second plate and the third plate, the mold opening between the first plate and the second plate is performed, The injection molding die according to claim 1.

3. The sprue bush portion has an elastic member, Before the punching by the punch portion, the sprue bush portion retreats in the second direction by the spring force of the elastic member, The injection molding die according to claim 1.

4. The punch portion is composed of an anchor pin, an Ej sleeve, and a punch cylinder. The Ej sleeve and the punch cylinder are in a cylindrical shape, The Ej sleeve houses the anchor pin, The punch cylinder has a three-layer structure that houses the Ej sleeve including the anchor pin, The injection molding die according to claim 1.

5. The anchor pin has a constricted portion at the tip, The anchor pin holds the runner portion punched by the punch portion at the constricted portion, The injection molding die according to claim 4.

6. With the runner part held by the anchor pin, after the punch cylinder has retracted in the first direction, the Ej sleeve moves in the second direction, whereby the runner part is removed from the constricted part. The injection mold according to claim 5.

7. The Ej sleeve is driven in conjunction with an ejector pin of a molded product formed in the cavity. The injection mold according to claim 6.

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