JP2002321255A - Injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the cooling period of the portion forming a molded product in a mold without complicating the structure of the mold. SOLUTION: A pair of grooves 56ga and 56gb having a fine width are formed to the end opposed to the basin 62R in the peripheral edge of a sprue 62 in opposed relationship.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding apparatus capable of efficiently cooling a molding material in a molding material supply passage extending to a cavity in a molding die.

[0002]

2. Description of the Related Art An injection molding apparatus includes, for example, a fixed mold 4 supported by a fixed support plate 2 as a mold group, a fixed mold 6 built in the fixed mold 4, and a movable mold. The movable mold 14 fixed to the support plate 24 via the frame member 18 supported by the support plate 24 on the side, and the movable mold 16 built in the movable mold 14, and the mold is opened when the mold is opened. And a projecting pin 26 for projecting an article from the mold group to the outside.

FIG. 11 does not show a mold clamping drive mechanism for driving the movable support plate 24 so as to approach or separate from the fixed support plate 2.

The fixed-side support plate 2 is fixed to a tie bar (not shown), and the movable-side support plate 24 is slidably supported by the tie bar.

[0005] The fixed-side support plate 2 has an inlet 2A to which a nozzle portion of an injection device (not shown) is connected. Further, the fixed mold 4 has a passage 4A communicating with the inlet 2A. Further, the fixed mold 6 is provided with a passage 4A.
6A which communicates with the Therefore, sprue 1
2 is formed inside by the inlet 2A, the passage 4A and the passage 6A.

At the end of the fixed mold 6, recesses 6 A and 6 B are formed with a sprue 12 interposed therebetween.

When opening or closing the mold, the fixed mold 4
A parting line PL is formed between the fixed mold 4 and the movable mold 14 so that the end faces of the movable molds 6 and 6 come into contact with or separate from the end faces of the movable molds 14 and 16.

[0008] At the portion of the movable mold 16 opposite to the recesses 6A and 6B of the fixed mold 6, there are formed projections 16A and 16B inserted into the recesses 6A and 6B with a predetermined gap. I have. Therefore, the recesses 6A and 6A
B and the convex portions 16A and 16B make a closed space.
Cavities 8 and 10 will be formed respectively.

The runner portions 8R and 10R are opposed to one end of the sprue 12 and have a parting line PL.
Is formed on. As shown in FIG. 12, a pool 12R is formed at the center of the runners 8R and 10R. The pool 12R is also referred to as a cold slag well or a sprue lock.
They are collected without being supplied to Pool 1
The depth of 2R is larger than the depth of runner portions 8R and 10R and the depth of cavities 8 and 10. Due to the collection of impurities and the like by the basin portion 12R, when the molded product is protruded by the projecting pin described later, the impurity is discharged together with the molded product. The portion corresponding to the pool 12R in the formed molded product also has a role of keeping the molded product in close contact with the movable mold 16 when the mold is opened.

The space between one end of the runner portion 8R and the cavity 8, and the other end of the runner portion 10R and the cavity 10
13, a gate 8G and a gate 10G are formed, respectively, as shown in FIG.

As shown in FIG. 14, an opening end of a through hole 28 is opened at a portion of the movable molds 14 and 16 facing the pool 12R. Through hole 28
Is formed by the through holes 14A and 16A of the movable mold 14. The projecting pin 26 is slidably inserted into the through hole 28.

One end of the projecting pin 26 is held by ejector support plates 20 and 22. The support plates 20 and 22 are connected to a ram of a clamping drive mechanism (not shown). As a result, when the support plate 24 is separated from the support plate 2 by the mold closing drive mechanism at the time of opening the mold, as shown by the two-dot chain line in FIG. It will move toward the pool 12R.

In such a configuration, when performing the injection molding, as shown in FIG. 11, in a mold-clamped state, first, the molten molding material is supplied to the sprue 12 and the runner 8.
R and 10R, the pool 12R, the gate 8G and the gate 10G are injected and filled into the cavities 8 and 10.

Next, after a predetermined cooling period has elapsed while maintaining the pressure in the cavities 8 and 10, the molding material is solidified in the cavities 8 and 10.

When the mold is opened by the mold clamping drive mechanism, the molded product is protruded from the movable mold 16 through the protruding pin 26.

In such a series of steps, a period required until the molten resin is cooled and gradually solidified is as follows:
The smaller the thickness of the molded product is, the shorter the region is, and the larger the thickness is, the longer the region is. Therefore, the period required for solidifying the portion corresponding to the above-mentioned pool portion 12R in the molded product is the longest period. As a result, there is an inconvenience that the step of taking out the molded product cannot be performed until the solidification of the portion corresponding to the pool portion 12R is completed, which leads to an increase in the unit cost of parts due to a prolonged molding cycle.

In view of the above, the above-mentioned well section 1 in the molded product is described.
In order to shorten the period required for cooling and solidifying the portion corresponding to 2R, for example, as shown in JP-A-6-134816, the thickness of the molded product corresponding to the end of the sprue is reduced. In addition, there has been proposed a device in which one end of a protruding portion projecting into a sprue is fixed to a movable-side mold.

In a series of molding cycles, a sprue bush is cooled in order to efficiently cool a portion corresponding to a sprue having a relatively long cooling period, as disclosed in Japanese Patent Application Laid-Open No. 6-210688, for example. A cooling medium passage is provided around a sprue bush.

[0019]

However, in the case where one end of the protruding portion protruding into the sprue is fixed to the movable mold as described above, the mold structure may be complicated. Also, it may be difficult to provide a cooling medium passage for cooling the sprue bush due to the structure of the mold.

In consideration of the above points, the present invention relates to an injection molding apparatus capable of efficiently cooling a molding material in a molding material supply passage extending to a cavity in a molding die. It is an object of the present invention to provide an injection molding apparatus capable of shortening a cooling period of a portion of a molding die where a molded product is formed without complicating the process.

[0021]

In order to achieve the above-mentioned object, an injection molding apparatus according to the present invention is provided in a cavity portion which is formed inside a molding die and forms a molded product from a molding material to be injected. A molding material supply path for injecting and supplying the molding material, and a groove formed in a portion of the molding material supply path of the molding die opposed to the vicinity of the pool portion communicating with the runner portion are provided.

[0022]

FIG. 1 schematically shows a main part of a first embodiment of an injection molding apparatus according to the present invention. In FIG.
The present apparatus is supported by a fixed mold 54 supported by a fixed support plate 52 as a mold group, a fixed mold 56 built in the fixed mold 54, and a movable support plate 74. Movable mold 64 fixed to a support plate 74 via a frame member 68
And movable side mold 66 built in movable side mold 64
And a projecting pin 66 for projecting the molded product from the mold group to the outside when the mold is opened.

In FIG. 1, the movable support plate 7 is provided.
The illustration of a mold-clamping drive mechanism and the like for driving the 4 to approach or separate from the fixed-side support plate 52 is omitted.

The fixed-side support plate 52 is fixed to a tie bar (not shown), and the movable-side support plate 74 is slidably supported by the tie bar.

The fixed-side support plate 52 has an inlet 52A to which a nozzle portion of an injection device (not shown) is connected. Further, the fixed mold 54 has a passage 54A communicating with the inlet 52A. Further, the fixed side mold 56
Has a passage 56A communicating with the passage 54A. Therefore, the sprue 62 whose cross-sectional area gradually increases from the support plate 52 toward the movable mold 66 is formed by the sprue 52 and the passage 5.
The support plate 52 and the fixed molds 54 and 56 are formed by the 4A and the passage 56A.

In the fixed mold 56, concave portions 56A and 56B formed corresponding to the outer shape of each molded product (not shown) are formed with the sprue 62 interposed therebetween.

When opening or closing the mold, the fixed mold 5
Parting line PL in which the end faces of movable molds 4 and 56 and the end faces of movable molds 64 and 66 abut or separate from each other
Is formed between the fixed mold 54 and the movable mold 64.

A portion of the movable mold 66 facing the recesses 56A and 56B of the fixed mold 56 is provided with a recess 56.
Convex portions 66A and 66B inserted into A and 56B with a predetermined gap are formed. Therefore, at the time of mold clamping, the concave portions 56A and 56B and the convex portions 66A and
6B, a closed space is formed, and cavities 58 and 60 respectively corresponding to the outer shapes of the obtained molded products are formed.

As shown in FIGS. 2 and 4, runner portions 58R and 60R are formed on the parting line PL so as to face one end of the sprue 62. In a central portion between the runner portion 58R and the runner portion 60R, a basin portion 62R is formed as shown in FIG. The basin 62R collects impurities in the molding material such as molten resin, degraded products, and the like without supplying them to the cavities 58 and 60. By collecting the impurities and the like in the pool 62R, when the molded product is projected by the projecting pin 62 described later, the impurities are discharged together with the molded product. In addition, a portion corresponding to the pool portion 62R in the formed molded product also has a role of keeping the molded product in close contact with the movable mold 66 when the mold is opened.

As shown in FIG. 2, the depth D of the pool 62R is the depth DR of the runners 60R and 58R.
It is larger than the depth of the cavities 58 and 60.

As shown in FIGS. 2 and 4, a pair of grooves 66ga and 66gb having a pair of narrow widths are formed along the extending direction of the runner portions 60R and 58R on the periphery of the pool portion 62R in the movable mold 66. Are formed.

In FIG. 2, the bottom of the groove 66ga extends obliquely to the upper left to extend a part of the opening end of the through hole 78 communicating with the pool 62R.
And through holes 78 are formed. The bottom of the groove 66gb is formed so as to intersect the runner 58R and the through hole 78 along the upper right diagonal direction so as to extend a part of the opening end of the through hole 78 communicating with the pool 62R. Have been.

Further, the well 6 in the fixed mold 56 is formed.
As shown in FIGS. 2 and 3, a pair of narrow grooves 56ga and 56gb having a narrow width are formed along the direction in which the runner portions 60R and 58R extend, as shown in FIGS.
a and 66 gb. 56g groove
a and 56 gb have a cross-sectional shape of groove 66ga, respectively.
And 66 gb are formed to be line-symmetric with the parting line PL as the axis of symmetry. Therefore, the bottom of the groove 56ga is formed to intersect the sprue 62 and the runner portion 60R, while the bottom of the groove 56gb is formed to intersect the sprue 62 and the runner portion 58R.

One end of the runner portion 58R and the cavity 58
And between the other end of the runner portion 60R and the cavity 60, as shown in FIGS.
A gate 58G and a gate 60G are formed respectively.

As shown in FIG. 1, the movable molds 64 and 66 have portions facing the pool 62R, as shown in FIG.
The opening end of the through hole 78 is open. The through hole 78
The movable dies 64 and 66 are formed by through holes 64A and 66A. A protruding pin 76 is inserted into the through hole 78.

One end of the projecting pin 76 is held by ejector support plates 70 and 72. The ejector support plates 70 and 72 are connected to a ram of a mold driving mechanism (not shown). Accordingly, when the mold is opened, when the support plate 74 is separated from the support plate 52 by the mold clamping drive mechanism as shown by the two-dot chain line in FIG. Accordingly, it moves toward the movable mold 64.

At the other end of the projecting pin 76, a truncated cone-shaped projection 76P projecting into the pool 62R is formed. The tip of the projection 76P extends to a predetermined position beyond a plane formed by the bottoms of the runner portions 58R and 60R. The shape of the projection 76P is not limited to a truncated cone, but may be a cylindrical shape.

Accordingly, the thickness of the portion corresponding to the pool 62R in the obtained molded product is reduced by the corresponding amount of the projection 76P. As a result, the portion corresponding to the pool portion 62R in the molded product is formed by the above-described groove 56ga.
And 56 gb and grooves 66 ga and 66 gb increase the heat radiation area as compared with the conventional device shown in FIG. 11, and the thickness of the portion is reduced by protrusion 76P, so that cooling is promoted in the cooling step in the molding cycle. The period until the completion of the cooling and solidification in the portion corresponding to the pool 62R is substantially equal to the period until the solidification of the molding material in the cavities 58 and 60 is completed.

In such a configuration, when performing injection molding, as shown in FIG. 1, in a mold-clamped state, first, a molten molding material is supplied to the sprue 62, the runner portions 60R and 58R, and the basin portion 62R. , Gate 58G
And each cavity 58 and 6 through gate 60G
A predetermined amount is injected into zero.

Next, after a predetermined cooling period has elapsed while maintaining the pressure in the cavities 58 and 60, the molding material is solidified in the cavities 58 and 60.

At this time, without complicating the mold structure,
And grooves 56ga and 56gb in the molding material;
By promoting heat radiation from the portions corresponding to the grooves 66ga and 66gb, the pool portion 62 in the molding material is formed.
The period from the start of cooling to the completion of solidification in the portion corresponding to R is shortened.

When the mold is opened by the mold clamping drive mechanism, each of the solidified molded products is ejected from the projecting pin 76.
The pool is pressed further, and the convex portion 66A of the movable mold 66 is pressed.
And 66B.

At this time, the portions corresponding to the pool portions 62R in the obtained molded product are the grooves 56ga and 56gb.
Then, the portions corresponding to the grooves 66ga and 66gb are reinforced and formed as a plurality of ribs, so that the rigidity of the portions corresponding to the sprue and the runner portion in the molded product is increased. Also, the grooves 56ga and 56
gb and the grooves 66ga and 66gb
Since it is substantially parallel to the extending direction of R and 58R, it is advantageous in terms of rigidity.

In addition, the basin 6 in the obtained molded product
In the portion corresponding to 2R, a gap corresponding to the projection 76P is formed in a substantially truncated cone shape. Therefore, the difference between the substantial wall thickness of the portion corresponding to the pool 62R and the average wall thickness of the molded product is smaller than that of the conventional method. The difference between the periods is small.

Since the gap is formed by the protrusion 75P formed integrally with the protruding pin 76, the molded product can be easily protruded regardless of an increase in frictional resistance at the time of release.

In the above-described example, the elongated groove having a predetermined width is provided in both the fixed mold 56 and the movable mold 66. However, the present invention is not limited to this example. As shown in FIGS. 5, 6, and 7, there is no groove provided in the movable mold 66 ', and the groove 56 is provided only in the fixed mold 56.
ga, 56 gb may be provided. In FIG.
In the example illustrated in FIG. 2, the same components are denoted by the same reference numerals, and the description thereof will not be repeated.

FIG. 8 shows a second embodiment of the injection molding apparatus according to the present invention.
2 shows a main part of the embodiment.

In FIG. 8, the same components as those in the example shown in FIG. 2 are denoted by the same reference numerals, and the description thereof will not be repeated.

In FIG. 8, the sprue 62 'has a passage 52A of the fixed mold 52 and a passage 54 of the fixed mold 54.
A and the passage 90A of the fixed mold 90.

In a portion of the stationary mold 90 facing the end of the passage 90A, a pool 62'R communicating with the runners 60R and 58R is formed. In addition,
The pool 62′R is provided with runners 60R and 58R.
It also communicates with the runner section that extends across. Also,
Elongated grooves 90ga and 90gb having a predetermined width are formed opposite to each other at an end of the periphery of the passage 90A of the fixed mold 90. Slender grooves 90ga, 90gb
As shown in FIG. 8 and FIG. 9, are formed along a direction substantially perpendicular to the direction in which the runner portions 60R and 58R extend, respectively.

In FIG. 8, the bottom of the groove 90ga is formed with a sprue 6 obliquely downward and to the right so as to extend a part of the open end of the passage 90A communicating with the pool 62'R.
2 ', formed so as to intersect with the runner portion. The bottom of the groove 90gb is formed so as to cross the sprue 62 'runner obliquely to the lower left so as to extend a part of the open end of the passage 90A.

In addition, the basin 6 in the movable mold 92.
8 and 10, an elongated groove 9 having a predetermined width along a direction substantially perpendicular to the direction in which the runner portions 60R and 58R extend.
2 ga and 92 gb are formed facing each other.

In FIG. 8, the bottom of the groove 92ga extends obliquely to the upper right so as to extend a part of the opening end of the through hole 92a communicating with the pool 62'R.
a, It is formed so as to cross the runner portion. Also, the bottom of the groove 92gb crosses the through hole 92a and the runner portion obliquely to the upper left so as to extend a part of the opening end of the through hole 92a communicating with the pool portion 62'R. Is formed. Therefore, grooves 92ga and 9
2 gb is formed to be line-symmetric with respect to the grooves 90 ga and 90 gb with the parting line PL as the axis of symmetry.

In such a configuration, when performing injection molding, a series of steps similar to the above-described example are performed.

At this time, the same function and effect as those of the above-described example can be obtained. Therefore, heat can be radiated from the portions corresponding to the grooves 90ga and 90gb and the grooves 92ga and 92gb in the molding material without complicating the mold structure. Is promoted, the period from the start of cooling to the completion of solidification in the portion corresponding to the pool portion 62′R in the molding material is shortened.

In this embodiment, the elongated grooves having a predetermined width are provided in both the fixed mold 90 and the movable mold 92. However, the present invention is not limited to this example. Without being provided on the mold 92, the fixed mold 9
The grooves 90ga and 90gb may be provided only in the zero.

[0057]

As is apparent from the above description, according to the injection molding apparatus of the present invention, the groove is formed in the portion facing the pool near the runner portion in the molding material supply path of the molding die. Since the portion corresponding to the vicinity of the basin in the molded article obtained by the formation is radiated through the groove, the cooling of the portion corresponding to the vicinity of the basin is promoted. Therefore, it is possible to shorten the cooling period of a part of the mold where a molded product is formed, without complicating the structure of the mold.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing a main part of a first embodiment of an injection molding apparatus according to the present invention.

FIG. 2 is an enlarged partial cross-sectional view showing a main part of FIG.

3 is a partial cross-sectional view of the portion shown in FIG. 2, taken along the line III-III.

FIG. 4 is a sectional view taken along the line IV-IV in the portion shown in FIG. 2;

FIG. 5 is a sectional view showing another example of the groove in the example shown in FIG. 1;

FIG. 6 is a partial sectional view taken along line VI-VI in the example shown in FIG. 5;

FIG. 7 is a partial sectional view taken along line VII-VII in the example shown in FIG. 5;

FIG. 8 is a partial sectional view schematically showing a main part of a second embodiment of the injection molding apparatus according to the present invention.

FIG. 9 is a partial cross-sectional view taken along line IX-IX in the example shown in FIG. 8;

FIG. 10 is a partial sectional view taken along line XX in the example shown in FIG. 8;

FIG. 11 is a sectional view schematically showing a main part of a conventional device.

FIG. 12 is a partial cross-sectional view showing an enlarged main part in the example shown in FIG. 11;

13 is a partial cross-sectional view taken along line XIII-XIII in the example shown in FIG.

14 is a partial cross-sectional view taken along line XIIII-XIIII in the example shown in FIG.

[Explanation of symbols]

62, 62 'sprue 56 fixed side mold 56ga, 56gb, 66ga, 66gb, 90ga,
90 gb, 92 ga, 92 gb Grooves 58R, 60R, runners 62R Pool basin 76 Projection pin 76p Projection

Claims (9)

[Claims] A molding material supply path for injecting and supplying the molding material to a cavity formed in the molding die and forming a molded product with the molding material to be injected; and the molding material supply of the molding die. And a groove formed in a portion facing the pool near the runner portion in the road. 2. The injection molding apparatus according to claim 1, wherein the groove is formed on at least one of a plurality of molding dies forming a parting line in the molding dies. 3. The injection molding apparatus according to claim 1, wherein the groove is formed along a direction in which the runner extends. 4. The injection molding apparatus according to claim 1, wherein the groove is formed along a direction substantially perpendicular to a direction in which the runner extends. 5. The injection molding apparatus according to claim 1, wherein a plurality of the grooves are formed. 6. A projection member having a projection so as to face the groove and the pool portion, and further comprising a projection member for projecting a molded product formed by the cavity from the cavity. 2. The injection molding apparatus according to 1. 7. The injection according to claim 6, wherein the groove is formed at a peripheral edge of an end of the molding die in which the projecting member is inserted, the end facing the pool portion. Molding equipment. 8. The injection molding apparatus according to claim 1, wherein a rib is formed at a portion corresponding to the groove in a molded product obtained by the molding die. 9. The injection molding apparatus according to claim 6, wherein a void is formed at a portion corresponding to the projection of the projecting member in a molded product obtained by the molding die.