JPH04232009A - Mold assembly in injection molding - Google Patents

Abstract

PURPOSE:To facilitate the releasing of workpiece by a method wherein a gate is provided at the mating part between the first and the second interior molds of an inner mold so as to extend runners from the gate to respective cavities. CONSTITUTION:At injection molding, the first and the second interior molds 21 and 22 of an inner mold 20 are mated together. Further, respective outer molds 25 are urged on the sides of the interior molds 21 and 22 so as to constitute cavities 34. Molding material 38 is injected from a nozzle 31, or the like to a gate 36 provided at the first and the second interior molds 21. and 22 so as to be guided by runners 33 in order to be poured in the cavities 34. Workpieces 37 are produced in the cavities 34 through the hardening of the molding material 38. At this time, the molding material 38 in the runners 33 hardens under the state being connected together at the gate 36. By separating the first and the second interior molds 21 and 22 from each other under the above-mentioned state, the connecting part of the molding material 38 in the runner 33 is cut apart. Furthermore, the workpieces 37 are released from the inner mold 20 and an outer mold 25. Thus, the workpieces 37 can be easily released.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold apparatus for injection molding, and more particularly to a mold apparatus for injection molding that improves yield.

0002

2. Description of the Related Art Conventionally, a mold apparatus for this type of injection molding will be explained with reference to FIGS. 6 and 7. In the figure, 1 is a fixed type and 2 is a movable type. Recesses 3 and 4 are formed on the inner surfaces of the fixed mold 1 and the movable mold 2, respectively, and when the fixed mold 1 and the movable mold 2 are brought into contact with each other, the recesses 3 and 4 face each other and create a mold part 6 of the workpiece 5 to be molded. is configured. Further, the fixed mold 1 is provided with a sprue 7 on the outer surface, and a runner 8 is opened from the sprue 7 to the mold portion 6.

[0003] When the nozzle 9 is opposed to the sprue 7 and a molding material such as molten resin is injected, the molding material is guided by the runner 8 and injected into the mold part 6. The molding material inside is hardened to form the workpiece 5. Then, by moving the movable mold 2 to separate it from the fixed mold 1 and pressing the workpiece 5 with the ejector pin 10, the fixed mold 1 and the movable mold 2 are released from the workpiece 5. When the workpiece 5 is released from the fixed mold 1, the molded material hardened by the runner 8 is cut at the thinner position of the runner 8. Further, the molding material remaining in the runner 8 is melted again and injected into the mold section 6.

0004

[Problems to be Solved by the Invention] In the conventional injection molding device described above, when a workpiece is released from the mold, the molding material hardened in the runner connected to the workpiece hinders the release. The mold release operation is complicated. Further, in order to be able to cut the molded material that has hardened within the runner, the middle portion of the runner is formed to be narrow. but,
If the runner is made thin, the pressure at the time of injecting the molding material cannot be increased, and the molding material cannot be reliably injected into the mold, which causes a decrease in the quality and yield of the workpiece.

[0005] Therefore, there are technical problems that need to be solved in order to make it easier to release the workpiece, stabilize the quality of the workpiece, and improve the yield. The purpose is to solve this problem.

[0006]

[Means for Solving the Problems] This invention has been proposed to achieve the above object, and consists of an inner mold and an outer mold provided on both sides of the inner mold. A mold device for injection molding that forms a mold part of a workpiece to be molded by a recess formed in the inner surface of each outer mold, and injects molten molding material into the mold part to mold the workpiece. hand,
The inner mold is formed from a first inner mold and a second inner mold which are divided into left and right parts, and a sprue is provided at the joint part of the first inner mold and the second inner mold on the upper surface of the inner mold. It is an object of the present invention to provide a mold device for injection molding, characterized in that a runner is provided extending from the sprue to each mold portion.

[0007]

[Operation] When performing injection molding, first, the first and second inner molds are joined together, and then the outer molds are pressed against the sides of the inner mold to form the mold part. Configure. Then, when the molten molding material is injected from a nozzle or the like into the sprue provided at the joining part of the first internal mold and the second internal mold, the molding material is guided by the runner and injected into the mold part. , the molding material hardens and a workpiece is formed within the mold section. At this time, the molded material in the runner is cured while being connected through the sprue. Thereafter, by separating the first internal mold and the second internal mold, the connecting portion of the molded material in the runner is cut. Then, the inner and outer molds are released from the workpiece.

[0008]

[Embodiment] An embodiment of the present invention will be described below with reference to FIG. 1 of the accompanying drawings.
This will be explained in detail with reference to FIGS. In the figure, 20 is an inner mold, and as shown in FIG. The upper parts of the mold 21 and the second internal mold 22 are formed with slopes that are inclined from the center to the sides. or,
Side surfaces 21a of the first internal mold 21 and second internal mold 22
, 22a have grooves 23, 23 carved in the vertical direction, and recesses 24, 24 connected to the grooves 23, 23 in the intermediate part.
is formed.

On the other hand, outer molds 25, 25 are provided on both sides of the inner mold 20.
are arranged, and the inner surfaces 25a of the outer molds 25, 25,
25a is formed along the side surfaces 21a and 22a of the inner mold 20. Moreover, the inner surfaces 25a, 2 of the outer molds 25, 25
Grooves 26, 26 are cut in the vertical direction in 5a, and the grooves 26, 26 are provided so as to be opposed to the grooves 23, 23 of the inner mold 20. Furthermore, recesses 27, 27 are formed in the intermediate portions of the grooves 26, 26 on the inner surfaces 25a, 25a, and the recesses 27, 27 are opposed to the recesses 24, 24 of the inner die 20 to shape the outer shape of the workpiece, which will be described later. It is set up to take. The first inner mold 21, the second inner mold 22, and the outer molds 25, 25 are configured to be movable in the left-right direction.

Further, auxiliary members 28 and 29 are provided on the sides of the outer molds 25 and 25, respectively.One auxiliary member 28 (on the right in FIG. 1) is fixed, and the other auxiliary member 29 is located on the left and right sides. It is free to move in any direction. In addition, the symbols 30 and 30 in the figure are ejector pins. Furthermore, a nozzle 31 that is vertically movable is provided at a predetermined position above. Further, 32, 32 are coil springs disposed between the first internal mold 21 and the second internal mold 22, and the coil springs 32, 32 are arranged between the first internal mold 21 and the second internal mold 22.
acts to separate the first internal mold 21 and the second internal mold 22 at a constant interval.

When performing injection molding, first, the movable auxiliary member 29 is moved toward the fixed auxiliary member 28 to join the first internal mold 21 and the second internal mold 22. At the same time, the inner surfaces 25a, 25a of the outer molds 25, 25 are pressed against the side surfaces 21a, 22a of the inner mold 20. At this time, as shown in FIG. 2, the grooves 23, 23 of the inner mold 20 and the outer molds 25, 25
Runners 33, 33 branched left and right from the upper center of the inner mold 20 are formed by the grooves 26, 26, and runners 33, 33 are formed by the recesses 24, 24 of the inner mold 20 and the recesses 27, 27 of the outer molds 25, 25. Mold parts 34, 34 are configured. Furthermore, the first internal mold 21
The runners 33, 33 are opened to form a sprue 36 at the upper end of the joint 35 between the second inner mold 22 and the second inner mold 22.

Then, the nozzle 31 is lowered to form the sprue 36.
When a molding material such as a molten resin is injected into the mold portion 34, the molding material is guided by the runners 33, 33 and
34. Therefore, the molding material hardens, and as shown in FIG.
As shown in FIG. 2, a workpiece 37 is formed within the mold parts 34, 34. Moreover, the molded materials 38, 38 in the runners 33, 33
are cured in a connected state at the sprue 36.

Next, the first inner mold 21 and the second inner mold 20 are separated.
The internal mold 22 of That is, the second inner mold 22, outer mold 25, and movable auxiliary member 29 are integrally moved to the side (to the right in the figure). In such a case, as shown in FIG.
The molded materials 38, 38 on both sides of the molded materials 38, 38 are separated from each other, and the connection portion between the molded materials 38, 38 is cut.

Then, as shown in FIG. 5, the outer molds 25, 25 are separated from the first inner mold 21 and the second inner mold 22, and the auxiliary members 28, 29 are separated from the outer molds 25, 25. , workpiece 37 with ejector pins 30, 30,
When 37 is pressed, the works 37, 37 are released from the mold. The mold release can be easily performed because the molded materials 38, 38 are cut.

Furthermore, the molded materials 38, 38 hardened within the runners 33, 33 are released from the mold at the same time as the works 37, 37. Therefore, the molding materials 38, 38 do not remain in the runners 33, 33, and the work of melting the molding materials remaining in the runners, as in the conventional method, becomes unnecessary.

[0016]

Effects of the Invention As described in detail in the above-mentioned embodiment, the present invention provides that when a molding material is injected into a sprue provided at the joining portion of the inner mold 20 divided into left and right parts, a runner branched from the sprue The molding material is injected into each mold part formed by opposing the outer mold on both sides of the inner mold. Then, the molding material hardens to form a workpiece within the mold section, and the molding material within the runner hardens while connected at the sprue. The molded material connected by the sprue is cut by separating the first and second inner molds.

[0017] Therefore, it is not necessary to make the runner thinner, and the molding material hardened within the runner can be easily cut to release the workpiece. It becomes possible to reliably inject the molding material into the mold part without reducing the pressure of the molding material, thereby stabilizing the quality of the workpiece and improving the yield. In addition, since mold parts are provided on both sides of the inner mold, two or more workpieces can be formed at the same time by one injection of molding material, so this invention has significant effects such as improving productivity. .

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a mold device.

FIG. 2 is a cross-sectional view showing a state in which mold devices are joined and molding material is injected.

FIG. 3 is a cross-sectional view showing a state in which the molding material is hardened in the mold device.

FIG. 4 is a sectional view showing a state in which a first inner mold and a second inner mold are separated from each other.

FIG. 5 is a sectional view showing a state in which the inner mold, the outer mold, and the auxiliary member are separated from each other.

FIG. 6 is a sectional view showing a conventional mold device.

FIG. 7 is a sectional view showing a state in which a fixed mold and a movable mold of a conventional mold apparatus are separated.

[Explanation of symbols]

20 Inner mold 21 First internal mold 21a Side 22 Second internal mold 22a Side 24 Recessed part 25 Outer mold 25a Inner surface 27 Recess 33 Runner 34 Mold section 35 Joint part 36 Sprue 37 Work 38 Molding material

Claims (1)

[Claims] Claim 1: A mold part of a workpiece, which is composed of an inner mold and an outer mold provided on both sides of the inner mold, and is molded in recesses formed on both sides of the inner mold and the inner side of each outer mold. A mold device for injection molding that molds a workpiece by injecting a molten molding material into the mold part, the mold device comprising: a first internal mold and a second internal mold that divide the internal mold into left and right parts; A sprue is provided at the joint part of the first inner mold and the second inner mold on the upper surface of the inner mold, and a runner is provided extending from the sprue to each mold part. Mold equipment in molding.