JPH08216189A - Injection mold - Google Patents

Abstract

(57) [Abstract] [Purpose] In the case of an injection molding die for a bottomed tubular body, in the case of a die equipped with a split die, it is adjacent to the mold cavity when the split die is opened and closed. The load on the sliding portion is reduced to reduce "galling", and even if foreign matter such as burnt residue is generated, it is difficult to adhere to the molded body. [Structure] 24a, which is one of the sliding parts of split mold 21a,
In the portion adjacent to the mold cavity, a sliding portion unlike a conventional die is not formed, but instead of the sliding portion, a simple abutting / separating surface composed of an inclined surface 241a is provided. By doing so, split mold 2
The load applied to the inclined surface 241a due to the opening and closing operation in the radial direction of the molded product of 1a is reduced, and as a result, there is no mold bite, and foreign matter accumulated on the inclined surface 241a and the sliding portion 24a is transferred to the molded body M. It does not adhere.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for molding a bottomed cylindrical molded body, which is an injection mold provided with a split mold.

[0002]

2. Description of the Related Art The simplest structure of an injection mold is a two-plate mold or a three-plate mold (3 plate).
Although it is a mold, a mold having a special structure with a split mold is used depending on the size and shape of the molded product to be molded or the material used.

For example, when molding a bottomed cylindrical molded body such as a container or a cap, as shown in FIG. 3, a fixed die a for molding the outer surface of the bottom of the molded body M and the outside of the side wall of the molded body M. 1. A first movable mold b which is composed of a plurality of split molds arranged in the circumferential direction and molds the outer surface of the side wall of the molded body M, and the molded body M.
A mold that is used in combination with a second movable mold c called a core for molding the inner surface of the mold is used.

When the mold is closed, the desired molded body M
When the mold cavity that can be molded is formed and the synthetic resin injected into the mold cavity is almost cured, the mold is split and the molded product is released. The opening and closing operation of this mold is performed by the opening and closing operation of the movable dies b and c in the axial direction of the molded body M (direction of arrow A) and the radial direction of the molded body M of the first movable die b. The splitting and closing operation (in the direction of arrow B) consists of the splitting and opening and closing operations in the radial direction. That is,
The movable dies b and c are split in the axial direction, and the first movable die b is also restricted in the radial direction while being restricted by the guide pins d and the sliding portions e and f provided on the die dividing surfaces. Split and close. The first movable die b and the ejecting plate j are integrally operated by an appropriate connecting means, for example, a connecting means k composed of a dovetail and a dovetail groove, for the axial splitting and closing operation.

[0005]

By the way, the sliding portion f
Is composed of sliding portions h and i formed on the left and right of the middle step portion g and slides in the radial direction with respect to the protruding plate j. Is large,
So-called "mold galling" occurs, and as a result, smooth sliding cannot be achieved over time. As a countermeasure, there is a method of providing a clearance that does not cause flash, or using an oil plate or the like, but the end of the sliding portion h is
It is difficult to adopt such a measure because the parting line is formed and the part where accuracy and hardness are required.

Even if such a measure can be adopted, the sliding portion h adjacent to the mold cavity has a small amount, but a small amount of scorched molding material, abrasion powder of the mold, lubricating oil, etc. However, there is also a problem that such foreign matter adheres to the molded product M in association with the above-described opening / closing operation, resulting in defective products.

The present invention solves the above-mentioned drawbacks of the prior art, reduces the load on the sliding portion adjacent to the mold cavity to reduce "mold scuffing", and also produces foreign matter such as burnt residue. However, the purpose of the present invention is to provide a mold that does not easily adhere to a molded product.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a first aspect of the present invention, which comprises a fixed die for molding the bottom outer surface of a bottomed tubular molding and a plurality of split dies for molding the sidewall outer surface of the molding. It has a movable mold and a second movable mold for molding the inner surface of the molded body, and the fixed mold and each movable mold can be opened and closed in the axial direction of the molded body, and further, the first movable mold. Is capable of splitting and splitting also in the radial direction of the molded body, and the splitting and splitting in the radial direction uses the splitting and splitting operation in the axial direction, and a guide pin protruding in the mold. In an injection molding die regulated by a sliding portion provided on a mold dividing surface that does not form a mold cavity surface, a portion of the sliding portion adjacent to the mold cavity is simply replaced by the sliding portion. Its main point is "injection molding dies characterized by abutting and separating surfaces".

That is, in the conventional first movable mold, the sliding portion formed on the mold dividing surface adjacent to the mold cavity is removed, and instead, a simple abutting / separating surface is formed to open the mold. At the time of splitting and closing, eliminating the sliding motion on the mold dividing surface,
Therefore, the main point is that smooth opening and closing operation can be maintained even if it is operated for a long time, and that even if foreign matter occurs, it does not move to the mold cavity, that is, the molded product. It is what

The "sliding portion provided on the mold dividing surface that does not form the mold cavity surface" in the present invention is the sliding portions e and f in the example of FIG. Similarly, in the example of FIG. 3, the “portion of the moving part adjacent to the mold cavity” refers to h of the sliding part f, the inner end of which is in contact with the mold cavity.

As the means for "making the sliding portion adjacent to the mold cavity a mere abutting / separating surface" in the present invention, as shown in FIGS. 1 and 2, an inclined surface is the simplest. And effective. Since the first movable mold is also split and closed in the radial direction of the molded product M, the direction of this inclination is, of course, an inclined surface in the direction away from the fixed mold in the mold splitting direction. Further, this inclined surface is not limited to a mere straight smooth surface as shown in FIGS. 1 and 2, and may be a curved surface.

[0012]

In the injection molding die of the present invention, of the sliding parts of the conventional mold, the part adjacent to the mold cavity is a simple abutting / separating surface instead of the sliding part. No die galling occurs, and even if a foreign matter occurs, the foreign matter is not pressed against the molded product by the die opening and closing operation of the first movable die.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing an embodiment of an injection-molding die of the present invention, showing a state when the die is closed together with its usage mode, and FIG. It is a cross-sectional view showing the state in the middle, the figure (a) is a figure showing the time just after shifting to the mold cleaving operation, and the figure (b) is a figure showing the state immediately before mold release In each case, it is a diagram showing a main part on the right side of the mold.

In these figures, 1 is a fixed mold having a mold cavity surface for molding the outer surface of the bottom of the molded body M which is a cylindrical container, and 2 is a mold cavity surface for molding the outer surface of the side wall of the molded body M. The first movable mold is two split molds 21a, 21 arranged around the outer surface of the side wall and having the same shape and size.
It consists of b. 3 is a second movable mold having a mold cavity for molding the inner surface of the molded body, and the fixed mold 1 and the first and second movable molds 2 and 3 are opened and closed in the axial direction of the molded body M. It is possible.

Reference numerals 4a and 4b are guide pins protruding from the fixed mold 1 in a direction inclined outward, and are split molds 21a and 2b.
Holes 22a and 22b through which the guide pins 4a and 4b can be freely inserted and removed are provided in the 1b. 23a, 2
3b and 24a, 24b are sliding portions provided on the mold dividing surfaces that do not form the mold cavity surface, and V-shaped slides are provided on the sliding portions 23a, 23b that are located away from the mold cavity. The movable blade 25a is formed, the fixed mold 1 is provided with a sliding groove 11a corresponding thereto, and the split molds 21a and 21b are slidable outward.

Most of the sliding portions 24a and 24b are slidable with respect to the protruding plate 5 facing the sliding portions 24a and 24b, but the portion adjacent to the mold cavity (left side in FIG. 2) is The straight inclined surfaces 241a and 241b are formed so as to merely abut / separate from the inclined surfaces 51a and 51b of the protruding plate 5 formed to face the inclined surfaces 241a and 241b when the radial splitting and closing are performed. ing. In addition, split molds 21a, 21
b has a structure in which an unillustrated connecting member operates integrally with the protruding plate 5 with respect to the axial splitting and closing operation. In addition, inside the inclined surfaces 51a and 51b of the protruding plate 5, the second movable mold 3 is formed together with the molded product M when the mold is closed.
A mold cavity surface is formed to form the upper edge of the.

Based on such a structure, the first movable die 2 utilizes the axial splitting and closing operation as a driving force, and guide pins 4a, 4b and sliding portions 23a, 23b and 24.
It is regulated by a and 24b so as to relatively open and close in the radial direction. Incidentally, 6 is a fixed side mounting plate, and 7 is a movable side mounting plate.

Next, a procedure for molding the molded body M using the injection molding die of the present invention having the above structure will be described.

As shown in FIG. 1, when the molds are closed to form a predetermined mold cavity, the molding material is injected and filled into the mold cavity, and is substantially cooled and solidified. Next, the second movable mold 3
As shown in FIG. 2 (a), the first movable die 2 and the protruding plate 5 are pulled to start the axial cleaving operation. Simultaneously with the start of this cleaving operation, the bottom of the molded body M is fixed to the fixed mold 1.
Release from the mold cavity surface of.

Simultaneously with the start of this axial splitting operation, the split dies 21a, 21b of the first movable die 2 start sliding on the sliding portions 23a, 23b and 24a, 24b. , The radial cleaving operation also starts. At this time, split mold 2
The inclined surfaces 241a and 241b of 1a and 21b are inclined surfaces 51a and 51a of the protruding plate 5 at the moment when the cleaving operation is started.
Separate from b.

At the time when a space sufficient for the mold M to be released is formed between the mold cavity surface of the fixed mold 1 and the movable molds 2 and 3 and the mold M, As shown in FIG. 2B, the first fixed mold 2 and the protruding plate 5 are stopped, and the second movable mold 3 continues to perform the cleaving operation together with the movable side mounting plate 7 for a predetermined distance. ,In some cases,
Further, the molded body M is released by using other releasing means (not shown) such as an ejection pin or an air ejection device. After releasing the molds, the molds are closed, a predetermined mold cavity is formed, and one cycle is completed, in the completely reverse procedure to the above. At the moment when this mold closing operation is completed, the inclined surfaces 241a, 24 of the split molds 21a, 21b are
1b abuts the inclined surfaces 51a and 51b of the protruding plate 5.

[0022]

In the injection molding die of the present invention, the portion of the sliding portion of the conventional die adjacent to the mold cavity is a simple abutting / separating surface instead of the sliding portion. Therefore, there is no mold galling, and even if foreign matter occurs,
No foreign matter is pressed against the molded product due to the mold opening / closing and closing operation of the first movable mold.

Therefore, even if the apparatus is operated for a long period of time, the opening and closing of the mold can be smoothly performed, the life of the molding mold can be extended, and maintenance can be facilitated. Furthermore, the rate of defective products can be suppressed, and equipment costs and manufacturing costs can be reduced as a whole.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of an injection-molding die of the present invention, showing a state when the die is closed together with its usage mode.

FIG. 2 is a cross-sectional view showing a state during a mold cleaving operation in the same as above, FIG. 2 (a) is a view showing a time just after shifting to the mold cleaving operation, and FIG. It is a figure which shows the state just before mold release, and is a figure which shows the principal part of the right side of a metallic mold in all cases.

FIG. 3 is a sectional view showing only an essential part of an example of a conventional mold.

[Explanation of symbols]

 1 Fixed type 2 1st movable type 3 2nd movable type 4a, 4b Guide pin 5 Protruding plate 6 Fixed side mounting plate 7 Movable side mounting plate 11a Sliding groove 21a, 21b Split mold 22a, 22b Hole 23a, 23b Sliding Moving part 24a, 24b Sliding part 51a, 51b Inclined surface 241a, 241b Inclined surface M Molded body

Claims (1)

[Claims] 1. A fixed mold for molding the outer surface of the bottom of a bottomed cylindrical molded body, a first movable mold composed of a plurality of split molds for molding the outer surface of the side wall of the molded body, and an inner surface of the molded body. It has a second movable mold for molding, and the fixed mold and each movable mold can be opened and closed in the axial direction of the molded body, and further, the first movable mold is in the radial direction of the molded body. It is also possible to split and close,
The opening and closing in the radial direction uses the opening and closing operation in the axial direction by using a guide pin protruding in the mold and a sliding portion provided on the mold dividing surface that does not form the mold cavity surface. In a regulated injection molding die, a portion of the sliding portion adjacent to the mold cavity is a simple abutting / separating surface instead of the sliding portion. .