JP2017140754A - Molding die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molding die capable of improving a die life, and further heightening filling property of a molding material, and molding highly accurately a molding.SOLUTION: A molding die includes a first molding die 10, and a second molding die 20 separable relatively from the first molding die 10, for defining a molding part C between itself and the first molding die 10. In the first molding die 10, a sub-gate 42 extending in a direction crossing a Z-direction, and opening at a part facing in the Z-direction, to the second molding die 20 in the molding part C.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a molding die.

  A mold for molding a molded product such as a resin material (hereinafter simply referred to as a mold) has a first mold and a second mold that define a molded part. When injection molding is performed using the above-described mold, first, a melted resin material (molding material) is injected into the molding part through the gate opening. Thereafter, by solidifying the resin material, a molded product having an outer shape following the inner shape of the molded portion is molded.

  In the above-described mold, the gate system is selected according to various conditions such as the shape of the molded product, the type of resin material, and molding conditions. One of the gate systems is a pin gate system. In the pin gate method, a gate opening extending in the movement direction is formed in a portion of the first mold opposite to the second mold in the movement direction of the first mold and the second mold (for example, the following patent document). 1).

JP-A-8-197583

However, in the configuration of Patent Document 1 described above, there is still room for improvement in terms of improving the filling property of the resin material into the molded part. Specifically, in the configuration of Patent Document 1 described above, since the gate opening extends linearly along the moving direction, the resin material is injected toward the bottom surface of the molded portion. The resin material injected from the gate opening into the molding part flows toward the bottom surface of the molding part and then spreads on the outer peripheral side of the molding part. Therefore, especially when the molded product has a thin plate shape (a shape whose dimension in the direction perpendicular to the moving direction is larger than that in the moving direction), the resin material injected from the gate opening is filled to the outer peripheral side of the molded part. It is hard to be done.
In this case, the filling density of the resin material on the outer peripheral side of the molded part is likely to be lower than the filling density of the resin material around the gate opening. If the density distribution of the resin material becomes non-uniform in the molded part, the molded product is likely to warp or deform.

  Further, in the configuration of Patent Document 1, since the gate opening extends linearly along the moving direction, the resin material collides with the portion of the bottom surface of the molded portion that faces the gate opening in the moving direction. When doing so, a large pressure acts. As a result, the bottom surface of the molded part is easily damaged locally.

  The present invention has been made in view of the above circumstances, and provides a molding die capable of improving the filling life of a molding material and molding a molded product with high accuracy while improving the mold life.

  In order to solve the above-described problems, a molding die according to one aspect of the present invention is configured to be able to contact and separate relative to the first molding die and the first molding die. A second molding die that defines a molding portion between the first molding die and the second molding die. The second molding die extends in a direction intersecting the moving direction of the first molding die and the second molding die, and the molding A first gate opening that is opened at a portion of the portion facing the second mold in the moving direction is formed.

According to this aspect, since the molding material flowing into the molding part through the first gate opening flows so as to spread on the outer peripheral side of the molding part, it becomes easy to uniformly supply the molding material to the entire molding part. Thereby, the density distribution of the resin material in the molding part can be made uniform, and the filling property of the resin material can be improved. As a result, a highly accurate molded product with less warpage and deformation can be formed.
Moreover, it can suppress that the bottom face of a shaping | molding part receives a local damage compared with the structure by which a molding material is supplied linearly along a moving direction toward the bottom face of a shaping | molding part. Thereby, the mold life can be improved.
Furthermore, since the first gate opening extends in a direction crossing the moving direction, the filling direction of the molding material is changed according to the position of the first gate opening. In this case, for example, the filling direction of the molding material can be controlled by laying out the first gate opening so that the molding material flows intensively in a specific direction on the outer peripheral side of the molding part. Can be further improved.

In the above aspect, the first gate opening is opened at a position protruding to the second molding die side in the moving direction with respect to a die mating surface of the first molding die with the second molding die. Also good.
According to this aspect, the inclination angle of the first gate opening with respect to the moving direction can be made larger than when the first gate opening is formed on the mold matching surface. Thereby, the molding material can be effectively filled on the outer peripheral side of the molding part.

In the above aspect, a gate bush may be detachably attached to the first mold, and the first gate opening may be formed in the gate bush.
According to this aspect, the first gate opening can be easily processed by making the gate bush separate from the first mold. In addition, for example, when the first gate opening needs to be replaced due to friction with the molding material, only the gate bush needs to be replaced, so that the maintainability can be improved.

In the above aspect, the flow path cross-sectional area of the first gate opening may be gradually reduced toward the downstream side in the flow direction.
According to this aspect, the opening edge of the first gate opening can be formed at an acute angle as compared with the case where the channel cross-sectional area of the first gate opening is formed uniformly. Thereby, in a gate cut process, a bigger shear force acts with respect to the connection part of a molded article and a gate part. Therefore, the gate cutting process can be performed smoothly and the remaining gate of the molded product can be reduced.

In the above aspect, the first mold is formed with a second gate opening that extends in the movement direction and opens at a portion of the first mold that faces the second mold in the movement direction. May be.
According to this aspect, by supplying the molding material through the second gate opening, it is possible to supply the resin material more uniformly over the entire molding portion. In this aspect, since the first gate opening is formed as described above, the resin material that passes through the second gate opening is used as compared with the conventional case where the resin material is supplied only from the second gate opening. Less. Therefore, local damage to the bottom surface of the molded part due to the resin material supplied from the second gate opening can be suppressed.

  According to the present invention, the mold life can be improved, the filling property of the resin material can be improved, and the molded product can be molded with high accuracy.

It is sectional drawing of the metal mold | die in embodiment of this invention. It is an enlarged view equivalent to the II section of FIG. It is an expansion perspective view of a gate bush. It is process drawing for demonstrating a gate cut process, Comprising: It is sectional drawing equivalent to FIG. It is process drawing for demonstrating a mold opening process, Comprising: It is sectional drawing equivalent to FIG. It is process drawing for demonstrating an extraction process, Comprising: It is sectional drawing equivalent to FIG. It is an expansion perspective view of the gate bush for demonstrating the 1st modification of embodiment. It is an expansion perspective view of a gate bush for explaining the 2nd modification of an embodiment. It is an expansion perspective view of the gate bush for demonstrating the 3rd modification of embodiment.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view of a mold 1 according to an embodiment of the present invention.
As shown in FIG. 1, a mold (molding mold) 1 includes a first mold 10 and a second mold configured to be movable relative to the first mold 10 in the Z direction (moving direction). And a mold 20. In the present embodiment, the first mold 10 is a fixed mold, and the second mold 20 is a movable mold that contacts and separates from the first mold 10. Moreover, in the following description, the 1st shaping | molding die 10 side may be called upper direction among Z directions, and the 2nd shaping | molding die 20 side may be called downward.

  The second mold 20 is disposed opposite to the first mold 10 in the Z direction. A molding recess 23 is formed on the mold mating surface 21 of the second molding die 20 with the first molding die 10. The molding recess 23 is recessed downward with respect to the die matching surface 21.

  The first mold 10 closes the molding recess 23 of the second mold 20 and has a mold matching surface 11 that abuts against the mold matching surface 21 of the second mold 20 during mold clamping. A space surrounded by the first molding die 10 (mold matching surface 11) and the molding recess 23 of the second molding die 20 defines a molding part C for molding the molded product S. . In addition, the molded product S of this embodiment has comprised the thin plate shape which makes a Z direction the thickness direction, for example.

  The first mold 10 is formed with a holding hole 14 penetrating the first mold 10 in the Z direction. A gate bush 13 is detachably mounted in the holding hole 14.

FIG. 2 is an enlarged view corresponding to section II in FIG.
As shown in FIG. 2, the holding hole 14 is formed in a multistage shape whose inner diameter is reduced as it goes downward. Specifically, the holding hole 14 has a large-diameter portion 14a and a small-diameter portion 14b connected to the large-diameter portion 14a from below.
The inner diameter of the large-diameter portion 14a is uniformly formed over the entire Z direction. A stopper surface 14c is formed at the lower end edge of the large diameter portion 14a so as to project to the inner peripheral side of the large diameter portion 14a.

  The upper end edge of the small diameter portion 14b is connected to the inner peripheral edge of the stopper surface 14c. The upper end portion of the small diameter portion 14b is a tapered portion 14d whose inner diameter gradually decreases as it goes downward. The lower end portion of the small diameter portion 14b is connected to the lower end edge of the tapered portion 14d. A lower end opening of the small diameter portion 14b opens into the molding portion C. In the illustrated example, the lower end opening of the small-diameter portion 14 b faces the bottom surface of the molding recess 23 in the Z direction.

The gate bush 13 is formed in a multistage cylindrical shape that follows the shape of the inner surface of the holding hole 14 while the axis O extends in the Z direction. The gate bush 13 supplies a molten resin material (molding material) supplied from a supply source (not shown) into the molding part C. Specifically, the gate bush 13 includes a bush main body portion 31 and a nozzle portion 32 that protrudes downward from the bush main body portion 31.
The bush main body portion 31 is fitted in the large diameter portion 14 a of the holding hole 14. In this case, the lower end surface of the bush main body 31 is close to or abuts on the stopper surface 14 c of the holding hole 14 from above.

FIG. 3 is an enlarged perspective view of the gate bush 13.
As shown in FIGS. 2 and 3, the nozzle portion 32 is formed to have a smaller diameter than the bush main body portion 31. The nozzle portion 32 is fitted into the small diameter portion 14 b of the holding hole 14 with the lower end portion protruding downward (inside the molding portion C) from the lower end opening portion of the holding hole 14. The upper end portion of the nozzle portion 32 is an upper tapered portion 33 that gradually decreases in diameter as it goes downward. The upper taper portion 33 faces the taper portion 14 d of the holding hole 14 in a state where the gate bush 13 is mounted in the holding hole 14. Moreover, the part which protruded from the holding hole 14 among the nozzle parts 32 is the lower side taper part 34 which is gradually diameter-reduced as it goes below.

  A gate hole 35 extending in the Z direction is formed in the gate bush 13 described above. The gate hole 35 is formed across the bush main body portion 31 and the nozzle portion 32 in the gate bush 13. In the illustrated example, the upper end of the gate hole 35 opens at the upper end surface of the bush main body 31. On the other hand, the lower end portion of the gate hole 35 terminates in the nozzle portion 32. The gate hole 35 is gradually reduced in diameter as it goes downward.

The nozzle portion 32 described above is formed with a plurality of gate openings (main gate 41 and sub-gate 42) that allow the gate hole 35 and the molding portion C to communicate with each other.
The main gate (second gate opening) 41 has a circular cross section perpendicular to the flow direction (Z direction) of the resin material. The main gate 41 extends downward from the lower end of the gate hole 35. The lower end of the main gate 41 opens downward at the lower end surface of the nozzle portion 32. That is, the main gate 41 faces the bottom surface of the molding part C in the Z direction. In the present embodiment, the channel cross-sectional area of the main gate 41 is smaller than that of the gate hole 35. Further, the flow passage cross-sectional area of the main gate 41 is uniformly formed over the entire region in the flow direction. However, the channel cross-sectional area of the main gate 41 may be gradually reduced in diameter as it goes downward (downstream in the flow direction).

  The sub-gate (first gate opening) 42 has a circular cross section perpendicular to the flow direction. The sub-gates 42 extend radially (four in the illustrated example) with respect to the axis O in a plan view as viewed from the Z direction. Each sub-gate 42 extends in a direction intersecting the axis O (Z direction) in a sectional view along the Z direction. Specifically, each sub-gate 42 extends in the direction away from the axis O (outside in the radial direction) as it goes downward. Each sub-gate 42 opens toward the direction intersecting the axis O on the outer peripheral surface of the lower tapered portion 34. In this case, each sub-gate 42 is directed toward the outer peripheral side of the molding part C.

  In addition, the channel cross-sectional area of each sub-gate 42 is formed uniformly over the entire flow direction. However, the channel cross-sectional area of each sub-gate 42 may be gradually reduced in diameter as it goes downward (downstream in the flow direction). The number of sub-gates 42 can be changed as appropriate. Further, in the example of FIG. 2, the channel cross-sectional area of the sub-gate 42 is smaller than the channel cross-sectional area of the main gate 41. In the example of FIG. 2, the entire main gate 41 and sub-gate 42 protrude downward from the mold matching surface 11, but at least part of the main gate 41 and the sub gate 42 may be positioned below the mold matching surface 11.

  In the present embodiment, a runner mold (not shown) is disposed above the first mold 10. The runner mold has a runner hole that connects between the gate hole 35 of the gate bush 13 and the supply source of the resin material. The runner mold is configured to be movable relative to the molds 10 and 20 in the Z direction.

[Injection molding method]
Next, a method for manufacturing the molded product S using the above-described mold 1 will be described.
First, as shown in FIGS. 1 and 2, the first mold 10 and the second mold 20 are clamped (clamping process). In the mold clamping process, the second mold 20 is moved closer to the first mold 10 along the Z direction until the mold mating surfaces 11 and 21 of the molds 10 and 20 abut each other in the Z direction. As a result, the molding part C is defined by the mold matching surface 11 of the first molding die 10 and the molding recess 23 of the second molding die 20.

  Next, the molding part C is filled with a molten resin material (filling step). Specifically, the resin material supplied from a supply source (not shown) flows into the gate hole 35 of the gate bush 13 through the runner hole of the runner mold described above. The resin material that has flowed into the gate hole 35 flows downward through the gate hole 35. Thereafter, the resin material flows into the molding part C through the gates 41 and 42 of the nozzle part 32. At this time, the resin material passing through the main gate 41 out of the resin material flows through the main gate 41 along the Z direction, and then flows into the molding portion C toward the bottom surface of the molding recess 23 (in FIG. 2). Arrow M). On the other hand, the resin material that passes through each sub-gate 42 out of the resin material flows in the direction crossing the Z-direction through each sub-gate 42 and then flows into the molding part C toward the outer peripheral side of the molding part C (see FIG. (See arrow N in 2). Thereby, the resin material is filled in the molding part C.

  Thereafter, the mold 1 is cooled to solidify the resin material (solidification step). Thereby, the resin molding 51 according to the inner surface shape of the mold 1 is molded. That is, the resin molded body 51 is formed by integrally forming a molded product S molded by the molded portion C and a gate portion G molded by the gate bush 13.

FIG. 4 is a process diagram for explaining the gate cutting process and is a cross-sectional view corresponding to FIG.
As shown in FIG. 4, the resin molded body 51 is cut between the gate portion G and the molded product S (gate cutting step). In the gate cutting step, the molds 10 and 20 are moved downward with respect to the runner mold while the molds 10 and 20 are clamped. Then, the molded product S moves downward with respect to the gate portion G, so that the molded product S is pulled downward with respect to the gate portion G. As a result, the resin molded body 51 is cut between the gate portion G and the molded product S. In particular, of the connection part between the molded product S and the gate part G, the part located in the sub-gate 42 is the part of the opening edge of the sub-gate 42 that is located above the gate part G (the upper end opening in FIG. 2). A shearing force acts in the Z direction from the edge 42a). As a result, the gate cut can be performed smoothly.

FIG. 5 is a process diagram for explaining the mold opening process and is a cross-sectional view corresponding to FIG. 1.
Next, as shown in FIG. 5, in the mold opening process, the second mold 20 is moved downward with respect to the first mold 10. As a result, the second mold 20 is separated from the first mold 10 while the molded product S is held in the molding recess 23.

FIG. 6 is a process diagram for explaining the extraction process, and is a cross-sectional view corresponding to FIG. 1.
As shown in FIG. 6, in the take-out step, the molded product S is taken out from the molding recess 23 of the second molding die 20 using an ejector pin or the like (not shown).
Thus, the molded product S is completed.

Thus, in this embodiment, it was set as the structure by which the subgate 42 extended in the direction which cross | intersects a Z direction was formed in the part which opposes the 2nd shaping | molding die 20 in the Z direction among the 1st shaping | molding dies.
According to this configuration, since the resin material flowing into the molding part C through the sub-gate 42 flows so as to spread on the outer peripheral side of the molding part C, it becomes easy to uniformly supply the resin material to the entire molding part C. Thereby, the density distribution of the resin material in the molding part C can be made uniform, and the filling property of the resin material can be improved. As a result, a highly accurate molded product S with less warpage and deformation can be formed.
Further, as compared with the configuration in which the resin material is linearly supplied in the Z direction toward the bottom surface of the molding portion C, it is possible to suppress the bottom surface of the molding portion C from being locally damaged. Thereby, the mold life can be improved.

  Since the sub gate 42 extends in a direction intersecting the axis O (Z direction), the filling direction of the resin material is changed according to the position of the sub gate 42. In this case, for example, the filling direction of the resin material can be controlled by laying out the sub-gate 42 so that the resin material intensively flows in a specific direction on the outer peripheral side of the molding part C, and the filling property Further improvement can be achieved.

In the present embodiment, the sub-gate 42 opens at a position that protrudes downward with respect to the mold-matching surface 11 of the first mold 10 with the second mold 20.
According to this configuration, the inclination angle of the sub-gate 42 with respect to the Z direction can be increased as compared with the case where the sub-gate 42 is formed on the mold matching surface 11. Thereby, the resin material can be effectively filled on the outer peripheral side of the molded part C.

In the present embodiment, the gate bush 13 is detachably attached to the first mold 10.
According to this configuration, the gate hole 35 and the gates 41 and 42 can be easily processed by making the gate bush 13 separate from the first mold 10. Further, for example, when the gates 41 and 42 need to be replaced due to friction with the resin material, only the gate bush 13 needs to be replaced, so that the maintainability can be improved.

  In the present embodiment, since a plurality of gates 41 and 42 are provided, the resin material supplied into the molding part C can be dispersed to each gate 41 and 42. Thereby, compared with the case where the resin material is passed from one gate, the shear rate of the resin material that passes through each of the gates 41 and 42 can be reduced. Therefore, wear on the inner surfaces of the gates 41 and 42 due to friction with the resin material can be suppressed, and the mold life can be improved.

  In the present embodiment, since the main gate 41 extending in the Z direction is formed on the gate bush 13, it becomes easy to supply the resin material to the central portion of the molding portion C. Therefore, the resin material can be supplied more uniformly over the entire molding part C. In this embodiment, since the sub-gate 42 is formed as described above, the resin material passing through the main gate 41 can be reduced as compared with the conventional case where the resin material is supplied only from the main gate 41. Therefore, local damage to the bottom surface of the molded part C due to the resin material supplied from the main gate 41 can be suppressed.

Next, a modification of this embodiment will be described. In each modification, the layout and shape of each gate formed on the gate bush are different from the above-described embodiment. In the following description, the same components as those in the above-described embodiment are denoted by the same reference numerals and description thereof is omitted.
(First modification)
FIG. 7 is an enlarged perspective view of the gate bush 100 for explaining a first modification of the present embodiment.
In the gate bush 100 shown in FIG. 7, only the above-described sub-gate (first gate opening) 42 is formed in the nozzle portion 32. That is, the main gate 41 (see FIG. 3) described above is not formed in the gate bush 100 of this modification. In the example shown in FIG. 7, six sub-gates 42 are formed at intervals in the circumferential direction around the axis O.

  In the present modification, since the resin material is not supplied linearly in the Z direction toward the bottom surface of the molded part C, it is possible to reliably suppress the local damage to the bottom surface of the molded part C.

(Second modification)
FIG. 8 is an enlarged perspective view of a gate bush 110 according to a second modification of the present embodiment.
In the gate bush 110 shown in FIG. 8, four sub-gates 111 are formed at intervals in the circumferential direction around the axis O. The cross-sectional shape orthogonal to the flow direction of each sub-gate 111 is formed in an oval shape with the circumferential direction around the axis O as the major axis direction. In addition, the sub-gate 111 is formed in a tapered shape in which the cross-sectional area of the flow path gradually decreases as it goes downward. In the example of FIG. 8, the sub-gate 111 is reduced as the dimensions in both the major axis direction and the minor axis direction move downward. However, the sub-gate 111 may be reduced in size only in one of the major axis direction and the minor axis direction. Further, the cross-sectional area of the sub-gate 111 may be uniform over the entire flow direction.

According to this configuration, the flow rate of the resin material passing through the sub-gate 111 can be increased by forming the sub-gate 111 in an oval shape. Thereby, the resin material can be supplied more efficiently toward the outer peripheral side of the molded part C.
Further, by forming the sub-gate 111 in a tapered shape, the upper end opening edge 111a of the sub-gate 111 can be formed at an acute angle compared to the case where the cross-sectional area of the sub-gate 111 is formed uniformly. Thereby, in the gate cut process mentioned above, a larger shearing force acts on the connection part between the molded product S and the gate part G. Therefore, the gate cutting process can be performed smoothly and the remaining gate of the molded product S can be reduced.

(Third Modification)
It is an expansion perspective view of the gate bush 120 which concerns on the 3rd modification of this embodiment.
As in the gate bush 120 shown in FIG. 9, only the sub-gate 111 may be formed in the nozzle portion 32.

The technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above-described embodiment and each modification, a plurality of sub-gates are formed at intervals in the circumferential direction. However, the present invention is not limited to this. That is, it is sufficient that at least one sub-gate is formed.

Further, if the sub-gate extends in a direction intersecting the Z direction, the inclination angle with respect to the Z direction can be changed as appropriate. In this case, the sub-gate may extend in a direction orthogonal to the Z direction.
Furthermore, the cross-sectional shape of the sub-gate is not limited to a circular shape or an oval shape, and various shapes such as a polygonal shape can be adopted.
Moreover, as long as each gate is a position which opposes the bottom face of the shaping | molding part C in a Z direction, you may arrange | position in arbitrary positions in the surface direction orthogonal to a Z direction.

In the above-described embodiment, the case where the thin plate-shaped molded product S is formed using the mold 1 has been described as an example. However, the present invention is not limited to this, and the present invention is applicable to the case where the molded product S having various shapes is formed. The configuration can be adopted.
Moreover, although embodiment mentioned above demonstrated the case where a resin material was used as a molding material, it is not restricted to this, For example, other materials, such as a glass-type material and a metal material, may be sufficient.

In the above-described embodiment, the case where the gate hole and each gate are formed in the gate bush has been described. However, the present invention is not limited to this, and the first mold may be directly formed with the gate hole and each gate. .
In the above-described embodiment, the case where the molding recess 23 is formed in the second molding die 20 has been described. However, if at least one of the first molding die 10 and the second molding die 20 has a molding recess. I do not care.

  In addition, it is possible to appropriately replace the components in the above-described embodiments with known components without departing from the spirit of the present invention.

1 ... Mold (molding die)
DESCRIPTION OF SYMBOLS 10 ... 1st shaping | molding die 11 ... Mold matching surface 13,100,110,120 ... Gate bush 20 ... 2nd shaping | molding die 41 ... Main gate (2nd gate opening)
42, 111 ... sub-gate (first gate opening)

Claims (5)

A first mold,
A second mold that can be moved toward and away from the first mold and that defines a molded portion with the first mold; and
The first mold has an opening at a portion extending in a direction crossing the moving direction of the first mold and the second mold and facing the second mold in the moving direction in the molding portion. A molding die characterized in that a first gate opening is formed.   The first gate opening is opened at a position protruding to the second mold side in the moving direction with respect to a mold mating surface of the first mold with the second mold. The molding die according to claim 1. A gate bush is detachably attached to the first mold.
The molding die according to claim 1 or 2, wherein the first gate opening is formed in the gate bush.   The mold for molding according to any one of claims 1 to 3, wherein the first gate opening has a flow path cross-sectional area that gradually decreases toward the downstream side in the flow direction.   The first mold is formed with a second gate opening that extends in the movement direction and opens at a portion of the first mold opposite to the second mold in the movement direction. The molding die according to any one of claims 1 to 4.

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