JPH03294056A - Injection molding die and injection molding method - Google Patents

Abstract

PURPOSE:To save consumption of molten metal and to reduce the development of defect of blow hole, etc., by pressurizing the molten metal in an injection sleeve with an injection plunger and supplying this into cavity through distributing grooves arranged to the injection sleeve side from main parting surfaces in dies. CONSTITUTION:The molten metal in the injection sleeve 5 is pressurizing with the injection plunger and supplied into plural cavities 16, 17 formed with the fixed die 1 and the mavable die 2 from the molten metal inlet part 8 through plural distributing grooves 10, 11 and runners 12, 13 to form plural products at the same time. In the above injection forming method, each distributing groove 10, 11 is formed so that center of the groove as seen with cross section containing axial line of the injection sleeve 5 is positioned to the injection sleeve 5 side from the main parting surfaces 3a, 4a of the dies. Further, it is desirable that directional turning angle of the molten metal flow passing through there is made to <=90 deg.. By this method, the molten metal passage length to each runner 12, 13 is shortened and the consumption of molten metal is saved, and involution of the air into the molten metal is prevented and the development of blow hole can be reduced and further, the casting can be easily taken out from the dies.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an injection mold and an injection molding method, and particularly to die casting, in which molten metal is distributed and supplied to a plurality of cavities and a plurality of products are simultaneously molded. The present invention relates to an injection mold and an injection molding method suitable for low pressure casting, plastic molding, etc.

[Conventional technology]

An injection molding method described in Japanese Patent Publication No. 1-40707 is known as so-called multi-cavity mold casting in which molten metal is distributed and supplied to a plurality of cavities to simultaneously mold a plurality of products. In this injection molding method, a distributor, that is, a spool core, having a plurality of distribution grooves dedicated to each cavity is placed at the molten metal inlet at the tip of the injection sleeve, and the molten metal in the injection sleeve is pressurized by the movement of an injection plunger. Molten metal is distributed and supplied from the inlet to a plurality of cavities via a plurality of distribution grooves and a plurality of runners dedicated to each cavity, thereby molding a plurality of products at the same time.

[Problem to be solved by the invention]

However, in the above conventional technology, no consideration is given to the optimal shape of the molten metal passage from the molten metal inlet to each runner, including each distribution groove, and the direction of molten metal flow in the distribution groove changes significantly by 90 degrees or more. As a result, the molten metal path length becomes longer, the amount of molten metal used to cast one product increases, and the principle of centrifugal casting creates voids on the inner diameter side at locations where the direction of molten metal flow changes significantly. There was a problem in that air was trapped in the runner, and this air was drawn into the molten metal at the runner section and remained in the cast product as a blow hole (diameter of 0.25 m+a or more).

In addition, the removal of the casting from the mold after the molten metal has solidified is
This is done by grasping the biscuit formed by solidifying the molten metal at the molten metal inlet with the claws of a robot, etc. At this time, the center of the direction changing part of the molten metal flow in the distribution groove is on the side of the reflection sleeve from the main dividing surface of the mold. Since the biscuit is located in the upper part of the product, it is difficult to make the biscuit sufficiently protrude from the product part, and the claws of a robot or the like that grip the biscuit hit the product part, making it difficult to take out the biscuit.

An object of the present invention is to provide injection molding that can reduce the amount of molten metal used by making the molten metal path length to each runner relatively short, and reduce the amount of air drawn into the molten metal at the runners to reduce the occurrence of defects. The present invention provides a mold and an injection molding method.

Another object of the present invention is to provide an injection mold and an injection molding method that allow easy removal of a casting from the mold using a robot or the like.

[Means to solve the problem]

In order to achieve the above object, the present invention provides an injection sleeve between the molten metal inlet portion and a plurality of runners dedicated to each cavity.
By providing a plurality of distribution grooves dedicated to each cavity corresponding to a plurality of runners, and applying pressure to the molten metal in the injection sleeve using a pressurizing means such as an injection plunger, a plurality of distribution grooves dedicated to each cavity are provided from the molten metal inlet. In an injection mold that simultaneously molds a plurality of products by distributing supply to a plurality of cavities via a distribution groove and a plurality of runners, the center of each distribution groove is the center of the groove when viewed in a cross section including the axis of the injection sleeve. is located closer to the injection sleeve than the main dividing surface of the mold.

Note that the "parting surface of the mold" refers to the dividing surface on which the molding gate opening into the cavity is located.

Preferably, each of the distribution grooves comprises a plurality of notches provided only at the tip of the injection sleeve. Each of the distribution grooves may be formed of a plurality of cuts provided in both the tip of the injection sleeve and a spool core disposed facing the molten metal inlet of the injection sleeve, or It may also be configured with a plurality of cuts provided only in the core.

In order to achieve the above object, the present invention applies pressure to the molten metal in the injection sleeve using a pressurizing means such as an injection plunger, so that a plurality of distribution grooves dedicated to each cavity are formed from the molten metal inlet of the injection sleeve. In an injection molding method in which a plurality of products are simultaneously molded by distributing and supplying the molten metal to a plurality of cavities via a plurality of runners, the center of the direction change part of the molten metal flow from the molten metal inlet to each distribution groove to each runner is , the direction of flow of the molten metal is changed so that the molten metal is located closer to the injection sleeve than the main dividing plane of the mold when viewed in a cross section including the axis of the injection sleeve.

[Effect]

By forming each distribution groove so that the center of the groove when viewed in a cross section that includes the axis of the injection sleeve is located closer to the injection sleeve than the main dividing surface of the mold, the center of the distribution groove is positioned closer to the spool than the main dividing surface of the mold. Compared to the conventional technology where the molten metal is located on the core side, the direction change angle of the molten metal flow from the molten metal inlet to the runner is 9.
0° or less, and the gap and molten metal flow tip surface (melt front) on the inner diameter side of the direction change part occur due to the difference in melt flow velocity between the inner diameter side and the outer diameter side of the direction change part of the molten metal flow. The turbulence is also reduced, the amount of air drawn into the molten metal in the runner section is reduced, and a high-quality cast product can be obtained. In addition, the molten metal path length is shortened, and the amount of molten metal used per cast product is also reduced.

In addition, by forming the groove so that the center of the groove when viewed in a cross section including the axis of the injection sleeve is located closer to the injection sleeve than the main dividing surface of the mold, the biscuit formed by the molten metal inlet of the casting can be made into a product more easily than before. This makes it possible to make the biscuit sufficiently protrude from the mold, making it easy to grasp the biscuit using the claws of a robot or the like and take out the cast product from the mold.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 7 in the case of a two-cavity mold used in a horizontal gui-casting device.

The molding die of this embodiment has a fixed die 1 and a movable die 2 as shown in FIGS. In the movable mold 2, the movable mold insert 4 and the spool core 6 are assembled into the mold body 2a. A plunger 7 is slidably fitted into the injection sleeve 5 , and the tip of the injection sleeve 5 abuts the spool core 6 , with a molten metal inlet 8 between the tip of the injection sleeve 5 and the spool core 6 . is forming.

An inlet recess 9 is formed in the end face of the spool core 6, and two independent distribution grooves are formed in the distal end of the injection sleeve 5 by providing two notches spaced apart on the left and right sides of the upper part, as shown in FIG. 1o and 11 are formed. Also,
Two runners 12 and 13 spaced apart from each other are provided on the mold dividing surfaces of the fixed mold insert 3 and the movable mold insert 4, that is, the main dividing surfaces 3a and 4a, which constitute the main dividing surface of the molding die. Two product cavities 16 and 17 are formed in these runners, spaced apart on the left and right, communicating through gates 14 and 15, respectively. One end of the distribution groove 10.11 is connected in communication with the melt inlet 8 via the inlet recess 9 of the spool core 6, and the other end is connected in communication with the corresponding runner 12.13. That is, the runners 12.13 are connected to each cavity 1.6
．． This runner is specially designed for runner 17.
Corresponding to 13, each cavity 16.17 is provided with a dedicated distribution groove 10.11.

As shown in FIGS. 1 and 5, the end surface of the tip of the injection sleeve 5 coincides with the main dividing surfaces 3a and 4a, and the distribution groove 1
0.11 is formed by providing a notch in the tip portion of the injection sleeve 5 as described above. As a result, in the closed state where the fixed mold 1 and the movable mold 2 are in contact with each other, the center of the distribution groove 10.11 as seen in the cross section including the axis of the injection sleeve 5, that is, the cross section shown in FIG. , 4a, and the direction change angle of the molten metal flow from the molten metal inlet portion 8 to each runner 12.13 via each distribution groove 10.11 is 90° or less.

The fixed mold 1 and the movable mold 2 are opened and closed by moving the movable mold 2 from side to side in FIGS. 1 and 5 by a hydraulic mechanism (not shown).

The cast product formed by solidifying the molten metal filled into the mold under pressure remains on the movable mold 2 side when the mold is opened, and after the mold is opened, the extrusion plate 18 shown in FIGS. 1 and 5 is moved by a hydraulic mechanism (not shown). By moving it to the right in the figure, the holder 19 extrudes it through a plurality of extrusion bins 2o fixed to the extrusion plate 18.

Next, the usage and operation of the mold described above will be explained.

By injecting the molten metal into the injection sleeve 5 from the holding furnace using a ladle and moving the plunger 7 from right to left in FIGS. from the inlet recess 9 of the injection sleeve 5 to the distribution groove 10.11 and the runner 12.1.
3 to the product cavity 16.15 from the gate 14.15.
17, and the two products are molded at the same time.

In the above molding process, the molten metal flows into each cavity 16.
The flow is divided by a distribution groove 10.11 dedicated to each cavity 16.17, and runners 12, 13, game) 14,
15 and product cavities 16 and 17, excellent distribution performance is achieved, and variations in the balance of molten metal supply to each product cavity for each casting shot are reduced. In addition, in this embodiment, the distribution groove 10°11 of the injection sleeve 5
, runner 12.13. Since the gate 14.15 and the product cavity 16.17 are all symmetrical in shape and arrangement, the product cavity 14.15 is filled with molten metal under the same conditions.

Therefore, the quality of the product obtained in the cavities 16 and 17 can be made uniform.

In addition, when the direction change angle of the molten metal flow from the molten metal inlet to each runner via each distribution groove is 90' or more as in the prior art described in Japanese Patent Publication No. 1-40707, As shown in FIGS. 9 and 10, each distribution groove 50
．． Due to the principle of centrifugal casting, a gap 54 is created on the inner diameter side at the molten metal flow direction changing part of the molten metal flow from the molten metal inlet section 8 including 51 to each runner 52, 53, and air accumulates there, and the direction of the molten metal flow is changed. Due to the difference in molten metal flow velocity between the inner diameter side and the outer diameter side of
A disturbance occurs. As a result, the air in the void 54 is drawn into the molten metal, as shown in FIG.
m or more) remains in the cast product. Furthermore, the length of the molten metal passage from the molten metal inlet portion 8 to each runner 52, 53 becomes long, and the amount of molten metal used to cast one product increases, which is uneconomical.

In contrast, in this embodiment, the direction change angle of the molten metal flowing from the molten metal inlet 8 through each distribution groove 10.11 to each runner 12.13 is 90° or less as described above. The difference in the flow velocity of the molten metal between the inner diameter side and the outer diameter side of the direction change part of the molten metal flow becomes small, and as shown in Figs. 1, 7, and 8, almost no voids are generated on the inner diameter side of the direction change part. Disturbances in the melt front 21 are also reduced. Therefore, the amount of air drawn into the molten metal in the runners 12 and 13 is reduced, making it possible to obtain a high quality cast product. Furthermore, the molten metal path length is shortened, and the amount of molten metal used per cast product is also reduced.

In addition, the removal of the casting from the mold after the molten metal has solidified is
This is done by grasping the biscuit formed by solidifying the molten metal at the molten metal inlet with the claws of a robot, etc. However, in the above-mentioned conventional technology, where the direction change angle of the molten metal flow is 90' or more, Since the center of the direction change part of the molten metal flow in the distribution groove 50, 51 is located on the opposite side of the injection sleeve 57 from the main dividing surface 56 of the mold, the molten metal inlet is located at the extrusion completion position of the plunger 58 in FIG. The biscuit 59 formed by solidifying the molten metal is transferred to the product section 60 as shown in FIG. 12(B).
It is not possible to make the robot protrude more fully, and the range into which the claw of the retrieval robot can be inserted becomes smaller.

Therefore, the claws of the robot that grips the biscuit 59 hit the product part, making it difficult to take out the cast product.

On the other hand, in this embodiment, the center of the distribution groove 10.11 when viewed in a cross section including the axis of the injection sleeve 5 is the main dividing surface 3a,
4a, the biscuit 22 formed by the molten metal inlet portion 8 of the casting is placed closer to the product portion 2 than the conventional biscuit 22, as shown in FIG. 12(A).
3, the range into which the claws of the take-out robot can be inserted becomes larger, and it becomes easier to grasp the biscuit 22 using the claws of the robot and take out the cast product. Therefore, it is possible to fully automate the injection molding process, including the removal of the cast material.

Another embodiment of the present invention will be described with reference to FIGS. 13 and 14. This embodiment shows a modification of the distribution groove. In the drawings, members equivalent to those shown in FIGS. 1 to 8 are designated by the same reference numerals.

In FIG. 13, distribution groove 10A of this embodiment.

11A is the tip of the injection sleeve 5A and the spool core 6A
It is formed by providing two cuts in each of the two sides. Also, in the embodiment shown in FIG. 14, the distribution grooves 10B and IIB are connected to the spool core 6B and the spool core 6
It is formed by providing two cuts in both B and B, respectively.

In the embodiment shown in FIG. 13, the injection sleeve 5A
The depth of the cut made at the tip of! 2 is larger than the depth 11 of the cut provided in the spool core 6A (I!2
>11), so that in this embodiment as well, in the closed state where the fixed mold 1 and the movable mold 2 are in contact with each other, the distribution as seen in the cross section including the axis of the injection sleeve 5A, that is, the cross section shown in FIG. The centers of the grooves 10A and IIA are the main dividing surfaces 3a and 4.
The runners 12A, 13 are located on the side of the injection sleeve 5A from the molten metal inlet 8 through the distribution grooves 10A, IIA.
The direction change angle of the molten metal flow leading to point A is 90° or less.

Furthermore, in the embodiment shown in FIG. 14, the depth 12 of the cut provided at the tip of the injection sleeve 5B is
Depth of cut made in B! , smaller than (12<1
1), the tip of the injection sleeve 5B is shifted to the right in the figure from the main dividing surfaces 3a, 4a. As a result, in this embodiment as well, the distribution groove 10B seen in a similar cross section.
, 11B are located closer to the injection sleeve 5B than the main dividing surfaces 3a, 4a, and the distribution grooves 10B, I
The direction change angle of the molten metal flowing to each runner 12B, 13B via the IB is 90° or less.

Therefore, in the embodiments shown in FIGS. 13 and 14, the same effects as in the first embodiment can be obtained.

Furthermore, if the idea of the embodiment shown in FIG. 14 is further developed, by providing two cuts only in the spool core 6, a distribution groove in which the center of the distribution groove is located closer to the injection sleeve than the main dividing surface can be created. This also allows the angle between the directional points of molten metal flow to be 90° or less,
A similar effect can be obtained.

In the above embodiment, the product cavities 16 and 17 are the third
As shown in the figures and FIG. 4, the shape and arrangement are bilaterally symmetrical, but the shape and arrangement may be asymmetrical. By appropriately selecting the cross-sectional area and direction of the 15 molten metal passages, it is possible to make the molten metal filling conditions for each product cavity the same, and it is possible to obtain a uniform product with the same quality as in the above embodiment.

Furthermore, although the above embodiments have been described with respect to a mold for a horizontal molding device, the present invention can be similarly applied to molds for a vertical molding device and an oblique molding device.

〔Effect of the invention〕

According to the present invention, the amount of air drawn into the molten metal in the runner section is reduced, making it possible to obtain a high-quality cast product, and also shortening the molten metal path length, making it possible to save the amount of molten metal used per ill of the cast product. . Therefore, a plurality of high-quality cast products can be produced with a minimum amount of molten metal.

In addition, it is now possible to make the biscuit formed by the molten metal inlet of the casting protrude more fully than before from the product part, making it easier to grasp the biscuit using the claws of a robot or the like and remove the casting from the mold. . Therefore, full automation of injection molding becomes easy.

[Brief explanation of drawings]

FIG. 1 is a sectional view taken along line II in FIG. 2(B) of an injection mold according to an embodiment of the present invention, and FIG. 2(A) and (
B) is a front view and a side view of the injection mold, respectively, FIG. 3 is a front view of the fixed mold seen from the line ■-■ in FIG. 2(A), and FIG. IV-IV in Figure (A)
FIG. 5 is a front view of the movable type seen from the line, and FIG.
), FIG. 6 is a perspective view showing the tip of the injection sleeve, and FIGS. 7 and 8 are sectional views similar to FIG. 1 showing different filling processes of molten metal, respectively. 9 to 11 are cross-sectional views corresponding to FIGS. 1, 7, and 8 showing different filling processes of molten metal in a conventional injection mold, and FIG. 12 (A) 12(B) is a diagram for explaining the ease with which a robot can take out a cast product molded by the present example, and FIG. This is a similar diagram for explaining the difficulty, and the 13th
14 are sectional views of essential parts of injection molding molds according to other embodiments of the present invention. Explanation of symbols 1... Fixed mold 2... Movable mold 3a, 4a... Main dividing surface 5... Injection sleeve 6... Spool core 7... Plunger 8... Molten metal inlet section 10. 11...Distribution groove 12.13...Runner 16.17...Cavity Fig. 2

Claims (7)

[Claims] (1) Between the molten metal inlet of the injection sleeve and the plurality of runners dedicated to each cavity, a plurality of distribution grooves dedicated to each cavity are provided corresponding to the plurality of runners, and the molten metal in the injection sleeve is transferred to the injection plunger, etc. An injection mold that distributes and supplies molten metal from the inlet portion to a plurality of cavities through a plurality of distribution grooves dedicated to each cavity and a plurality of runners by applying pressure using a pressurizing means, and molds a plurality of products at the same time. An injection mold, wherein each of the distribution grooves is formed such that the center of the groove when viewed in a cross section including the axis of the injection sleeve is located closer to the injection sleeve than the main dividing surface of the mold. (2) The injection mold according to claim 1, wherein each of the distribution grooves comprises a plurality of notches provided only at the tip of the injection sleeve. (3) In the injection molding mold according to claim 1, each of the distribution grooves includes a plurality of grooves provided on both the tip of the injection sleeve and the spool core disposed facing the molten metal inlet of the injection sleeve. An injection mold characterized by consisting of notches. (4) The injection mold according to claim 1, wherein each of the distribution grooves comprises a plurality of cuts provided only in the spool core disposed facing the molten metal inlet of the injection sleeve. Injection mold. (5) Between the molten metal inlet of the injection sleeve and the plurality of runners dedicated to each cavity, a plurality of distribution grooves dedicated to each cavity are provided corresponding to the plurality of runners, and the molten metal in the injection sleeve is transferred to the injection plunger, etc. An injection mold that distributes and supplies molten metal from the inlet portion to a plurality of cavities through a plurality of distribution grooves dedicated to each cavity and a plurality of runners by applying pressure using a pressurizing means, and molds a plurality of products at the same time. , the shape of the molten metal passage from the molten metal inlet portion including each of the distribution grooves to each of the runners is such that the direction change angle of the molten metal flow is 90°.
An injection molding mold characterized in that it is formed so that the temperature is less than or equal to °. (6) By applying pressure to the molten metal in the injection sleeve using a pressurizing means such as an injection plunger, the molten metal is poured into multiple cavities from the molten metal inlet of the injection sleeve through multiple distribution grooves dedicated to each cavity and multiple runners. distributed and supplied to
In an injection molding method for simultaneously molding a plurality of products, the center of the direction changing portion of the molten metal flow from the molten metal inlet through each distribution groove to each runner is located at the center of the mold when viewed in a cross section including the axis of the injection sleeve. An injection molding method characterized by changing the direction of molten metal flow so that it is located closer to the injection sleeve than the main dividing plane. (7) By applying pressure to the molten metal in the injection sleeve using a pressurizing means such as an injection plunger, the molten metal is poured into multiple cavities from the molten metal inlet of the injection sleeve through multiple distribution grooves dedicated to each cavity and multiple runners. distributed and supplied to
In an injection molding method for simultaneously molding multiple products, the direction of the molten metal flow is changed so that the direction change angle of the molten metal flow from the molten metal inlet through each distribution groove to each runner is 90 degrees or less. Characteristic injection molding method.