JPH04331114A - Injection molding machine - Google Patents

Abstract

PURPOSE:To allow primary moldings to surely remain in a female mold in an injection molding machine wherein formation of the half body of a hollow product is performed by displacing a movable mold between at least two mold clamping positions and also formation of the hollow product is performed by joining two half bodies. CONSTITUTION:An injection molding machine is provided with a fixed mold and a movable mold which is freely opened and closed for the fixed mold and freely displaced in the prescribed direction in an intrasurface vertical for the opening/closing direction. One part of a male mold provided in the molding part of both molds is freely slidably split in the mold drawing direction for the other part of the male mold. This other part of the male mold is interlocked with one part thereof via the prescribed play in the mold opening direction. Furthermore one part of the male mold is held so that the same forms one molding face together with the other part thereof in the mold clamping position by providing an energizing means. At a time of mold opening, one part of the male mold is delayed by the play part in comparison with the other part thereof and opened.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is capable of molding half of a hollow product by displacing one side of the mold between at least two mold clamping positions, and of molding a hollow product by joining the halves. The present invention relates to an injection molding machine, and particularly to an injection molding machine in which the structure of the core mold and the method for opening the mold are improved to ensure that the core remains in the primary molded product.

0002

BACKGROUND OF THE INVENTION When producing synthetic resin products, blow molding or injection molding are generally used.

For example, when manufacturing a hollow product using a blow molding method, the molten resin is extruded into a cylindrical parison using an accumulator head, both sides of the parison are sandwiched between molds, and air is blown into the inside to form the hollow product. In this case, relatively large burrs are formed on the top and bottom of the product due to the mold, and a nozzle hole for blowing air remains on the product, resulting in a completely sealed hollow product. Moreover, it is difficult to manufacture to a uniform thickness.

On the other hand, when manufacturing hollow products using the injection molding method, a method is adopted in which the hollow molded product is divided into two halves, each of which is injection molded, and the two halves are joined by abutting each other. In this case, there is an advantage that completely sealed hollow products and hollow products with complex shapes can be successfully manufactured.

For example, as shown in Japanese Unexamined Patent Publication No. 62-87315, a slide mold is provided between a fixed mold and a movable mold, and the movable mold and the slide mold are placed in the first mold clamping position, and the male and female of both are placed in the first clamping position. A pair of half bodies is manufactured by injecting molten resin into the cavity formed by the mold part, and then the slide mold is slid to set the movable mold and the slide mold to the second mold clamping position, and the half bodies are manufactured. A die slide injection molding method is known in which the two halves are joined by abutting the two halves and injecting molten resin into the abutting portion.

[0006]

However, in the die slide injection molding method described in the above-mentioned conventional publication, due to the structure of the male mold part of the movable mold and the sliding mold, that is, the core mold part, when opening the mold after primary molding, The product halves, which are primary molded products, may adhere to the core mold part and come off from the female mold part, and there is a risk that the halves will not meet accurately in the next secondary molding, resulting in a defective product. Ta.

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide an injection molding machine that can ensure that the core of the primary molded product remains when the mold is opened after primary molding.

[0008]

[Means for Solving the Problems] Therefore, the injection molding machine according to the present invention has a fixed mold and a movable mold that can be opened and closed with respect to the fixed mold and can be displaced in a predetermined direction in a plane perpendicular to the opening and closing direction. At least two molding parts are provided between the fixed mold and the movable mold, and by displacing the movable mold between at least two mold clamping positions, molding a half body of the hollow product; In an injection molding machine capable of joining two halves to form a hollow product, a part of the male mold provided in the molding section is slidable in the mold removal direction relative to the other part. The structure is such that a part of the male mold and other parts interlock with each other through a predetermined play in the mold opening direction, and at the mold clamping position, a part of the male mold interlocks with the other part. A part of the male mold is held so as to form one molding surface with the mold, and a means is provided for urging the part of the male mold to open later than other parts by the amount of play when the mold is opened. The main points are as follows.

The present invention is highly effective when applied to a die slide type injection molding machine in which a movable mold slides as shown in Japanese Patent Application Laid-Open No. 62-87315, but when the movable mold rotates, A rotary injection molding machine that manufactures split bodies and joins half bodies (patent application No. 2-20872)
The present invention can also be applied to (see No. 0). That is, the relative displacement of the movable type includes both sliding and rotation.

0010

[Operation] When the fixed mold and the movable mold are matched and the molten resin is first injected, the molten resin passes through the primary runner and is injected into the cavity of the mold part to produce half the product, and the movable mold is opened. It will be done.

At this time, a part of the male mold part is slidably divided in the mold opening direction with respect to other parts, and a part of the male mold part and the other parts are separated in a predetermined direction in the mold opening direction. Since it is configured to work together through the play, when the mold is opened after the primary injection, the other part of the male mold part is opened by the distance of the play, and a part of the male mold part is opened by the distance of the play. is pressed and held against the opposing female mold part, and when the mold is opened to some extent, a part of the male mold part begins to open and the pressing of the primary injection product is released, and the entire core is then opened.

After that, the movable molds are relatively displaced, the movable molds are matched, the halves are abutted, molten resin is secondarily injected to join the abutting parts of the halves, and the molds are opened. hollow products are manufactured.

[0013] As a result of the male mold part being opened while pressing the primary molded product against the female mold part with a part of the male mold part, the primary molded product reliably remains in the female mold part.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below based on specific examples shown in the drawings. 1 to 5 show a die slide type injection molding machine according to an embodiment of the present invention. First, to explain the overall configuration, in FIGS. 1 and 2, a mounting frame 11 is provided on a bed 10 of an injection molding machine 1, a die sliding type mold 2 is supported on the mounting frame 11, and the bed 10 is provided with a mounting frame 11. A molten resin injection mechanism 3 is disposed on the mold 10 to face the mold 2, and the injection mechanism 3 includes a hopper 30 for storing the molten resin, a nozzle 31 for injecting the molten resin, a pressurizing cylinder 32, and a nozzle 31. It is constituted by a drive device 33 that advances and retreats.

[0015] The mold 2 also has a slide mold 22.
Die slide cylinder 2 that slides the die in the vertical direction
3 is provided, and a mold opening/closing cylinder 24 for opening and closing the movable mold 20 is also provided.

The mold 2 also includes a movable mold 20 and a fixed mold 21.
A slide mold 22 is disposed between the fixed mold 2 and the fixed mold 2.
1 and the slide mold 22 have sprues 210, 220, 2
21 is bored in communication with the mold dividing surface. Further, a female mold part 200, a male mold part 201, and a runner 202 leading to both mold parts 200, 201 are formed on the mold cutting surface of the movable mold 20, and a side gate 203 leading to the male mold part 201 and a female mold part 200 are formed. A submarine gate 204 is formed.

On the other hand, on the mold cutting surface of the slide mold 22, there are a female mold part 222 and a female mold part 222 that are matched with the mold parts 201 and 200 on the movable mold 20 side to form a half-shaped cavity that is divided into two products. A male part 223 is formed, and a female part 222
A submarine gate 224 is drilled leading to.

Although not shown in FIGS. 1 and 2, in the movable mold 20 and the slide mold 22, some of the male mold parts 201 and 223 provided in the molding part are oriented in the mold removal direction with respect to other parts. The male parts 201 and 223 are slidably divided into two parts.
A part of the male mold part 201, 223 is configured to interlock with the other part through a predetermined play in the mold opening direction, and a biasing means is provided. The male mold part 201 forms one molding surface together with the mold part 201.
, 223 are held, while at the time of mold opening, a part of the male mold is provided so that it opens later than other parts by the amount of play.

That is, to explain in detail using FIGS. 3 to 5, the male mold part 201 of the movable mold 20 has a mold surface part 205 for molding a product, which includes most of the surfaces substantially parallel to the mold removal direction.
and a pressing portion 206 having a surface perpendicular to the die cutting direction, and are provided so as to be able to slide in the die cutting direction independently of each other.
Further, the rear end of the mold surface portion 205 is fixed to a mounting plate 208 of the movable mold 20, and a spring member 209 is compressed between the portion including the pressing portion 206 and the mounting plate 208. In addition, the mold surface part 205
A fitting protrusion P is provided in the portion including the pressing portion 206, and a fitting groove D is provided in the portion including the pressing portion 206.
is formed, both P and D are slidably fitted to each other,
Further, a play 207 is provided between the fitting groove D and the fitting protrusion P so that the pressing part 206 opens the mold later than the mold surface part 205. Moreover, the male mold part 223 of the slide mold 22 has a similar structure.

Next, the manufacturing method will be explained.

When manufacturing a hollow product, the slide mold 22 is first set to the first mold clamping position, the movable mold 20 is advanced by the mold opening/closing cylinder 24, and the female mold portions 200 of the movable mold 20 and the slide mold 21 are moved forward. , 222 and male parts 201, 2
23, a half-shaped cavity is formed by dividing the product into two. In this state, the drive device 33 is operated to move the nozzle 31 forward, and the pressurizing cylinder 32 is operated to remove the molten resin in the hopper 30. is ejected. Then, the molten resin is injected into the cavity of the mold part through the sprues 200, 220, the primary runner 202, and the submarine gates 204, 224 to manufacture the half body W. Once the half body W is manufactured, the nozzle 31 As the movable mold 20 is moved back, the mold opening/closing cylinder 24 is operated to open the movable mold 20.

At that time, at the mold clamping position, the male mold part 201
, 223 are held by a spring member so as to form one molding surface together with the mold surface portion, and when the mold is opened, the pressing portion of the male mold portion opens with a delay from the mold surface portion by an amount of play.

That is, to explain the male mold part 201 of the movable mold 20, when the movable mold 20 starts to be retreated when the mold is opened, the mold surface part 205 touches the mounting plate 20 as shown in FIG.
8, but the part including the pressing part 206 is pressed against the slide mold 22 by the action of the spring member 209,
The half body W is pressed against the female mold part 221 by the pressing part 206.

When the mold surface portion 205 retreats by the distance of the play 207, the fitting protrusion P comes into contact with the rear end of the fitting groove D, and as shown in FIG. The entire movable mold 20 is opened, and the half body W is thus reliably held within the female mold part 221.

When the primary molding is completed in this way, the slide mold 22 is slid from the first mold clamping position to the upper second mold clamping position, the movable mold 20 is moved forward and is mated with the slide mold 22, Half body W in female mold parts 200, 222
When the molten resin is injected in this state, the molten resin is injected into the cavity of the mold part through the sprues 200, 221, the secondary runner 203 and the side gate 203, and the molten resin is injected into the abutting part of the half body W. are joined to produce a hollow product, and the nozzle 31 and movable mold 20 are retracted again to perform ejection.

In the mold structure of this embodiment as described above, the male mold part 201 is divided into the mold surface part 205 and the pressing part 206, and when the mold is opened after primary injection, the pressing part 206 presses the half body W into the female mold. Since the mold surface part 205 is cut out by the distance of the play 207 while being pressed against the mold part 222, and then the whole mold is opened, the half body W can be reliably left in the female mold part 222, and the secondary injection This can prevent the occurrence of defective products.

Furthermore, in the mold structure of this embodiment, the male mold part 20
1 is divided into a mold surface part 205 and a pressing part 206, both of which can be slid independently of each other, and a play 207 is formed between the two to allow the core of the half body W to remain. , the mold structure is not so complicated and it is advantageous in terms of cost.

FIG. 6 shows a second embodiment of the present invention. In this embodiment, the mold surface part 205 is formed integrally with the movable mold 20 main body, while the pressing part 206 is formed separately from the movable mold 20 main body and is attached to the movable mold 20 main body so as to be slidable in the mold removal direction. In addition, a spring member 209 is compressed between the main body of the movable die 20 and the pressing portion 206. Note that hydraulic pressure may be applied instead of the spring force of the spring member 209. Furthermore, since the mold opening method is the same as in the above embodiment, its explanation will be omitted.

FIG. 7 shows a third embodiment of the present invention. In this embodiment, the mold surface portion 205 is integrally formed with the main body of the movable mold 20, and a guide hole is bored in the center of the mold surface portion 205.
A rod-shaped pressing portion 206 is slidably accommodated therein, and hydraulic pressure is applied to the rear end of the pressing portion 206. It should be noted that the mold opening method in this embodiment is the same as that in the first embodiment, so the explanation thereof will be omitted.

[0031]

As described above, according to the injection molding machine of the present invention, a part of the male mold provided in the molding section is divided so as to be slidable in the mold removal direction with respect to other parts, and A part of the male mold and other parts are interlocked through a predetermined play in the mold opening direction, and at the mold clamping position, a part of the male mold is held so that it forms one molding surface with the other parts. However, when opening the mold, one part of the male mold opens with a delay of the play compared to other parts, which has the effect of ensuring that the primary molded product remains in the female mold without complicating the mold structure. be.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing a die slide type injection molding machine having a structure according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing the above molding machine.

FIG. 3 is an enlarged cross-sectional configuration diagram showing main parts of the molding machine.

FIG. 4 is a sectional view showing the state of the molding machine at the time of starting mold opening.

FIG. 5 is a sectional view showing the state of the molding machine in the latter half of the mold opening period.

FIG. 6 is a cross-sectional configuration diagram showing another embodiment of the present invention.

FIG. 7 is a cross-sectional configuration diagram showing still another embodiment of the present invention.

[Explanation of symbols]

20 Movable type 201 Male part 205 Mold surface part 206 Pressing part 21 Fixed type 22 Slide type

Claims (1)

[Claims] [Claim 1] A fixed mold and a movable mold that can be opened and closed with respect to the fixed mold and can be displaced in a predetermined direction in a plane perpendicular to the opening and closing direction, and between the fixed mold and the movable mold. , at least two molding sections are provided, and the movable mold is displaced between at least two mold clamping positions to mold half the hollow product and join the two halves to mold the hollow product. In an injection molding machine capable of performing molding, a part of the male mold provided in the molding section is divided so as to be slidable in the mold opening direction with respect to other parts, and a predetermined play is made in the mold opening direction. A part of the male mold and another part are configured to interlock with each other through the mold, and at the mold clamping position, the part of the male mold is moved so that the part of the male mold forms one molding surface with the other part. An injection molding machine characterized by being provided with means for holding a part of the male mold and urging the part of the male mold to open later than other parts by the amount of the play when the mold is opened.