JP3253665B2 - Manufacturing equipment for hollow resin molded products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a manufacturing apparatus for molding a resin product having a hollow portion inside the product.

[0002]

2. Description of the Related Art Conventionally, in a resin manufacturing apparatus in which a molten resin is injected into a mold cavity from an injection molding machine and molded, the injection machine itself is provided with a backflow preventing means for preventing a backflow of the molten resin. Devices are known. In other words, if a certain amount of molten resin is injected into the cavity and then the resin flows back to the injection machine again, the resin in the cavity becomes insufficient, causing sink marks and the like, This is because bubbles may remain in the injection machine, and means for preventing such backflow are provided in the injection machine itself.

[0003]

However, in such a manufacturing apparatus, particularly in the case of an apparatus for manufacturing a resin product having a hollow inside of a molded product, a method in which a resin backflow prevention means is provided in the injection machine itself is not used. Failure to leave bubbles in the product could not be completely prevented. That is, in the molding of such a hollow product, after injecting the molten resin into the mold cavity, a pressurized gas is introduced into the resin of the cavity, and the gas occupied space is molded as a hollow portion. However, the injected pressurized gas does not stay in the cavity but permeates toward the upstream of the injection of the molten resin. And there is a problem that molding failure is caused. Then, such gas permeation was in a state where it could occur very easily because the degree of melting of the resin on the upstream side of the filling was high.

[0004]

[Means for Solving the Problems] To solve such problems.
The present invention consists of a fixed type and a movable type,
An injection machine for injecting a molten resin from the injection nozzle toward the mold cavity is made, and the mold runners for guiding the injected molten resin into the mold calibration <br/> in Viti, the molten resin in the cavity In a manufacturing apparatus for a hollow resin molded article having a gas injection means for injecting a gas into the inside, a resin backflow prevention means is provided in a mold runner portion downstream of an injection nozzle, and a resin backflow prevention means is provided .
Was spring biased towards the injection nozzle
A valve body is provided, and the valve body forms a resin injection flow path by injection of molten resin.
Open, resin backflow or gas backflow due to gas injection pressure
Is automatically blocked, and resin injection
Gas injection means is provided separately from the mold cavity.
Open and close the gas passage communicating with a part of the
A gas injection member for injecting gas into the part
I do.

[0005]

By providing a means for preventing backflow of the molten resin injected into the cavity in the mold runner portion close to the cavity, gas is prevented from permeating into the resin passage on the upstream side thereof, and the next shot is prevented. There is no problem that the air biting resin is sometimes injected. In addition, a predetermined amount of resin can be reliably filled, and the molding quality is improved.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the apparatus for producing a hollow resin molded product according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is an embodiment diagram when the manufacturing apparatus of the present invention is applied to a hot runner type mold apparatus, and FIG. 2 is an enlarged view of a main part.

As shown in FIG. 1, a manufacturing apparatus 1 applied to a hot runner type mold apparatus has a movable mold body 3 that opens a mold with respect to a fixed mold body 2, A cavity 4 formed by the main bodies 2 and 3, a hot runner block 6 incorporated between the fixed mold main body 2 and the fixed side mounting plate 5, and a molding machine 7 for injecting molten resin.
It has.

A molten resin injected from an injection nozzle 8 of a molding machine 7 as an injection section toward a nozzle touch piece 9 is supplied to a runner section 10 of a hot runner block 6, a hot nozzle 11, and a mold runner of a mold. It is led into the cavity 4 via the part 12.

Then, for example, the hot runner block 6 is heated by a cartridge heater or a sheath heater, and the hot nozzle 11 is heated by a band heater 13 mounted outside the nozzle bush.

A resin check valve 15 is provided upstream of the mold runner section 12. As shown in FIG. 2, the resin check valve 15 urges a valve member composed of a ball 16 with a spring 17 to close the hot nozzle 11 outlet 11a. When the pressure is injected, the flow path is opened by the pressure, and the flow path is otherwise closed.

In the embodiment, the cavity is filled from a plurality of gates through a plurality of hot nozzles 11, but the number of gates is of course arbitrary.

By the way, a fixed type book on the injection nozzle 8 side is used.
The movable body 3 is provided with a gas injector 18 separately from the body 2 . The gas injector 18 includes a piston 19 that slides in a cylinder, and a gas injection member 20 integrated with the piston 19. The gas injection device 18 opens and closes a gas passage 21 outside the gas injection member 19. Is cavity 4
The cavity 4 can be made to come and go, and a hole can be made in the resin surface layer in the cavity 4.

The hot runner type manufacturing apparatus 1 as described above
When the molten resin is injected from the injection nozzle 8 of the molding machine 7, the injected molten resin flows from the runner portion 10 of the hot runner block 6 to the plurality of hot nozzles 11, each resin check valve 15, and each mold runner. The cavity 4 is filled through the part 12.

A gas is injected into the resin when the surface layer of the resin filled in the cavity 4 becomes semi-solid and the inside is not solidified.

That is, the piston 19 of the gas injector 18
1 moves rightward in FIG. 1, makes a hole in the resin surface layer by the tip of the gas injection member 20, and then retreats leftward again to open the gas passage 21.

For this reason, the pressurized gas enters the inside of the resin through the hole formed in the surface layer, penetrates the unsolidified portion inside the thick portion, and forms the hollow portion 22.

At this time, the gas permeates from the cavity 4 toward the upstream of the resin filling outside, and tries to proceed toward the hot runner block 6 through the mold runner section 12.
It is blocked by the resin check valve 15 and does not enter upstream. That is, the resin check valve 15
Is to prevent not only the backflow of the resin but also the entry of gas.

For this reason, even when the resin flow path such as the runner section 10 between the injection nozzle 8 and the cavity 4 is long, if the gas is sealed by the mold runner section 12 close to the cavity 4, the next time. There is no problem that the resin mixed with gas is filled into the cavity 4 at the time of the shot. In addition, the cavity 4 can be reliably filled with a predetermined amount of resin.

Next, an embodiment applied to a cold runner type mold will be described with reference to FIGS. FIG. 3 is an embodiment diagram when applied to a cold runner type mold apparatus, FIG.
Is an enlarged view of a main part.

The manufacturing apparatus 31 has substantially the same configuration as the hot runner type mold apparatus, except that a cavity 34 formed by a fixed main body 32 and a movable main body 33 in a clamped state.
Is a type in which a resin is filled from one gate.

A band heater 4 is provided outside the nozzle touch piece 39 communicating with the injection nozzle 38 of the molding machine 37.
3 is provided, and a sprue bush 44 is provided downstream thereof via a resin check valve 45. The inside of the sprue bush 44 becomes the mold runner part 42.

The resin check valve 45 is provided with a cone-shaped valve member 46 urged by a spring 47. The operation of the valve member 46 is the same as that of the hot runner type ball 16, that is, the flow path is opened by the injection pressure at the time of resin injection, and is closed at other times.

Therefore, the effect of the cold runner type is the same as that of the hot runner type, and not only prevents the backflow of the resin but also seals the gas injected from the gas injection device 48, thereby preventing the resin from flowing upstream. Prevents gas from entering the side. The valve member 46 and the ball 1 as described above are used.
6, the number of gates, types such as a hot runner and a cold runner, etc., may of course be any combination.

[0024]

As described above, according to the present invention, the fixed type,
Mold cavities made of movable molds and formed in a mold-clamped state
Injection machine that injects molten resin from the injection nozzle
And a mold that guides the injected molten resin into the mold cavity
Inject gas into the runner and the molten resin inside the cavity.
For manufacturing a hollow resin molded article having a gas injection means
Of resin flow to the mold runner downstream of the injection nozzle
Prevention means is provided, and the resin backflow prevention means is directed to the injection nozzle.
A valve member biased by a spring.
Opens the resin injection flow path by injecting the molten resin,
Automatically prevents resin backflow or gas backflow due to
Gas injection into the mold separately from the resin injection nozzle.
Gas inlet communicating with a part of the mold cavity.
A gas that opens and closes the path and injects gas into the molten resin
Since comprises an injection member, providing a resin backflow preventing means to the mold runners, by to block also the gas for blow molding while reducing the backflow prevention of the resin by the action of the gas injection pressure, when such a continuous molding However, it is possible to prevent such a problem that the resin mixed with the gas is filled in the cavity to cause molding failure. Further, since a predetermined amount of resin can be reliably filled in the cavity, the molding quality is improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment in which the manufacturing apparatus of the present invention is applied to a hot runner type mold apparatus.

FIG. 2 is an enlarged view of the main part.

FIG. 3 is an embodiment diagram when the manufacturing apparatus is applied to a cold runner type mold apparatus;

FIG. 4 is an enlarged view of the main part.

[Explanation of reference numerals] 1, 31: manufacturing apparatus, 2, 3, 32, 33: fixed type,
Movable mold, 4,34 ... cavity, 7,34 ... molding
Machine, 8, 38 ... injection nozzle, 15, 45 ... resin backflow
Prevention means, 16, 46 ... valve member, 18, 48 ... gas
Injection means, 20: gas injection member, 21: gas injection hole
Road.

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Kenichi Okada 1-10-1 Shinsayama, Sayama-shi, Saitama Honda Engineering Co., Ltd. (56) References JP-A-5-124064 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B29C 45/26 B29C 45/00 B29C 45/28

Claims (1)

(57) [Claims] 1. A fixed type and a movable type, which are in a mold-clamped state.
An injection machine for injecting a molten resin from the injection nozzle toward the mold cavity formed, and the mold runners for guiding the molten resin injected into the mold key <br/> Yabiti, molten resin in the cavity In a manufacturing apparatus for a hollow resin molded article having a gas injection means for injecting a gas into the inside, a resin backflow prevention means is provided in a mold runner portion downstream of the injection nozzle, and the resin backflow prevention means is provided on the injection nozzle. Toward
A valve member biased by the pulling, wherein the valve member
The resin injection flow path is opened by injecting grease, and the resin injection
A configuration that automatically prevents backflow of fat or gas
And, in the mold and the injection nozzle of the resin separately gas injection means
A gas passage communicating with a part of the mold cavity
Gas to inject gas into the molten resin
Comprises input member, hollow resin molded article manufacturing apparatus characterized by and this.