JP2003211513A - Injection molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection molding machine which prevents the generation of a stringing phenomenon accompanied by mold opening. <P>SOLUTION: The injection molding machine has a fixed platen, the mold attached to the fixed platen, an injection nozzle 11 arranged so as to be freely brought into contact with the mold and injecting a molding compound and a cooling air supply part for supplying cooling air toward the injection nozzle 11. In this case, since the injection nozzle 11 is cooled by cooling air, the stringing phenomenon accompanied by mold opening is not generated and a mold assembly is not damaged. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding machine.

[0002]

2. Description of the Related Art Conventionally, in an injection molding machine, a resin as a molding material which is heated and melted in a heating cylinder of an injection device is injected to fill a cavity space in a mold device, A molded product can be obtained by cooling and solidifying in the cavity space.

The injection molding machine has a mold device, a mold clamping device and an injection device. The mold device includes a fixed mold and a movable mold, and the mold clamping, the mold clamping, and the mold opening are performed by advancing and retracting the movable mold by the mold clamping device. In addition, the injection device includes a heating cylinder, and a screw that is rotatably and reciprocally disposed inside the heating cylinder. Then, by advancing the screw, the resin is injected from the injection nozzle attached to the front end of the heating cylinder to fill the cavity space.

By the way, the injection device is supported on a frame of an injection molding machine and is moved forward and backward by driving a driving source, and a nozzle port formed at a front end of an injection nozzle is brought into contact with the fixed mold. To be separated.

FIG. 2 is a sectional view for explaining a resin stringing phenomenon in a conventional injection molding machine.

In the figure, 11 is an injection nozzle attached to the front end of a heating cylinder (not shown), 12a is an injection nozzle main body, 12b is a heater attached to the outer periphery of the injection nozzle main body 12a, and 13 is the front end of the injection nozzle 11. No. 15 is a nozzle port formed on the fixed mold, 15 is a fixed mold, and 16 is a sprue formed on the fixed mold 15. The fixed mold 15 is attached to a fixed platen (not shown).

In the injection molding machine having the above-mentioned structure, after the mold is closed and clamped by a mold clamping device (not shown), the molten resin is injected into the injection nozzle 1
1 through the sprue 16 to fill a cavity space (not shown) in the mold device. continue,
When the mold device is cooled, the resin in the cavity space is cooled and solidified to form the molded product 14. Similarly, the resin remaining in the sprue 16 is cooled and solidified to become the sprue portion 17.

Next, the mold device is opened and the movable mold (not shown) is retracted, so that the molded product 14 and the sprue portion 17 are retracted (moved to the left in the drawing). To be At this time, since the temperature of the injection nozzle 11 is set to be equal to or higher than the melting point of the resin, the resin is in a molten state and cut at the boundary between the injection nozzle 11 and the fixed mold 15.

Subsequently, an ejector pin (not shown) provided in the movable mold is advanced, and the molded product 14 and the sprue portion 17 are pushed out and taken out.

[0010]

However, in the conventional injection molding machine, when the temperature of the injection nozzle 11 is set high, the resin may not be cut off at the boundary portion. In that case, the stringing phenomenon occurs. Will occur. As a result, as shown in the drawing, the thread-shaped resin 18 is integrally formed with the sprue portion 17 at the tip of the sprue portion 17. When the resin 18 is sandwiched between the movable mold and the fixed mold 15 as the mold device is closed, the mold device is damaged.

An object of the present invention is to solve the problems of the conventional injection molding machine and to provide an injection molding machine in which the stringing phenomenon does not occur due to mold opening.

[0012]

To this end, in the injection molding machine of the present invention, a fixed platen, a mold attached to the fixed platen, and a mold that is disposed so as to be in contact with the mold, And a cooling gas supply unit that supplies a cooling gas toward the injection nozzle.

In another injection molding machine of the present invention, the mold further comprises a sprue bush having a sprue for passing a molding material injected from the injection nozzle.

The cooling gas supply unit has a supply passage which penetrates the sprue bush and is opened to the inner peripheral surface of the recess formed in the sprue bush.

In still another injection molding machine of the present invention,
Further, the cooling gas supply unit is a supply path that is arranged along the inner peripheral surface of a through hole formed in the fixed platen and has an open tip.

In still another injection molding machine of the present invention,
Furthermore, the cooling gas is intermittently supplied by a control valve arranged in the supply path.

In still another injection molding machine of the present invention,
Further, it has a control unit that opens the control valve from the start of mold closing to the end of mold opening.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this case, a disk molding machine as an injection molding machine will be described. The disk molding machine molds a disk substrate as a molded product, and for that purpose, the disk molding machine has a disk molding mold as a mold device.

FIG. 1 is a sectional view showing a main part of a disk molding machine according to the first embodiment of the present invention, and FIG. 3 is a sectional view of a sprue bush according to the first embodiment of the present invention.

In the figure, reference numeral 21 denotes a fixed side mold assembly as a first mold attached to a stationary platen (not shown), and the mold assembly 21 is a base plate 22 as a first support plate. , The base plate 22
A disk plate 23 as a first mirror surface plate attached to the base plate 22 by means of a bolt b1, and is arranged so as to face the fixed platen side in the base plate 22, and is attached to the base plate 22 by a bolt b2 so that the base plate 22 becomes a fixed platen. The locating ring 25 is positioned relative to the locating ring 25, and the sprue bush 26 is disposed in front of the locating ring 25 (left side in FIG. 1) and adjacent to the locating ring 25. It should be noted that the locate ring 25 passes through the injection nozzle 11 disposed so as to come into contact with the mold assembly 21,
A through hole 20 is provided.

The sprue bush 26 is formed in a rear half portion (right half portion in FIG. 3), a flange portion 26a brought into contact with the locate ring 25, and a front half portion (left half portion in FIG. 3). A recessed portion that is composed of a tubular portion 26b having a diameter smaller than that of the flange portion 26a, and that accommodates the front end (the left end in FIG. 1) of the injection nozzle 11 at the rear end (the right end in the drawing) of the sprue bush 26 and abuts it. 27 is formed in communication with the through hole 20, and a die 28 is formed at the front end of the sprue bush 26 so as to face the cavity C. Then, the recess 27 and the die 2
A sprue 29 for communicating the resin as a molding material injected from the injection nozzle 11 is formed by communicating with the spout 8. The diameter of the sprue 29 is increased toward the front.

The injection nozzle 11 is attached to the front end of a heating cylinder (not shown) as a cylinder member constituting the injection device, and a screw as an injection member is rotatably and forwardly and backwardly movable in the heating cylinder. It is arranged. Then, at the time of the measuring step, when the screw is rotated, the resin is supplied from the hopper arranged at a predetermined position of the heating cylinder, is melted with the rotation of the screw, and is advanced to the front of the screw. It can be stored. The screw is retracted accordingly.
Further, when the screw is advanced during the injection process,
The resin stored in front of the screw is injected from the injection nozzle 11 and filled in the cavity space C.
At this time, the injection device is advanced and the front end of the injection nozzle 11 is brought into contact with the sprue bush 26.

By the way, a not-shown stamper for forming irregularities on the information surface of the disc substrate is attached to the disc plate 23, and the inner peripheral edge of the stamper is provided on the outer side in the radial direction of the cylindrical portion 26b. A stamper presser bush (not shown) is provided for pressing. The mold assembly 21 is also provided with an air probe or the like (not shown) for blowing compressed air onto a disk substrate (not shown) to release the disk substrate from the disc plate 23.

An annular first guide ring 30 is arranged on the outer periphery of the disc plate 23, and the first guide ring 30 is attached to the base plate 22 by a bolt b3.

On the other hand, 32 is a movable-side mold assembly as a second mold attached to a movable platen (not shown). The mold assembly 32 is a base plate 35 and a bolt b4 on the base plate 35. The attached intermediate plate 40 as a second supporting plate, a disc plate 36 as a second mirror plate which is attached to the intermediate plate 40 by a bolt b5 and is arranged to face the disc plate 23, and the base plate. 35
A guide member 44 disposed inside the movable platen and attached to the intermediate plate 40 by a bolt b6, and moved forward and backward along the guide member 44 (moved in the left-right direction in FIG. 1) to the front end (see FIG. (The right end in 1)
A cut punch 4 having a shape corresponding to that of the die 28.
8 is provided. A concave portion (not shown) formed of an undercut portion is formed at the front end of the cut punch 48.

Further, an annular second guide ring 38 having a shape corresponding to the first guide ring 30 is arranged on the outer periphery of the disc plate 36, and the second guide ring 38 is intermediately mounted by a bolt b7. It is attached to the plate 40.

Inside the guide member 44, a flange 51 formed integrally with the cut punch 48 is provided so as to be movable back and forth. Further, a cut punch returning spring 52 is arranged in front of the flange 51 (right side in FIG. 1), and the cut punch returning spring 52 causes the cut punch 4 to move.
8 is urged toward the rear (to the left in FIG. 1).

The mold assemblies 21 and 32 constitute a disk molding mold, and a mold clamping device (not shown) is provided to bring the mold assembly 32 into and out of contact with the mold assembly 21. To be done. By driving a mold clamping motor (not shown) as a first driving unit to move the mold assembly 32 forward and backward, the mold for disk molding can be closed, clamped and opened. At the time of closing and mold clamping, the cavity space C is formed between the disk plates 23 and 36.
Is formed.

When the flange 51 is moved forward (moved to the right in FIG. 1) by driving a not-shown motor for punching, which serves as a second drive portion, during mold clamping, the cut punch 48 moves forward. And enters the die 28. As a result, the resin in the cavity space C can be perforated. An eject tab bush (not shown) for projecting the disc substrate is disposed radially outward of the front half portion (right half portion in FIG. 1) of the cut punch 48, and is arranged radially outward of the eject tab bush. An air probe (not shown) for blowing compressed air onto the disc substrate to release the disc substrate from the disc plate 36 is provided. Also,
The mold assembly 32 is also provided with ejector pins and the like (not shown).

First and second temperature control channels 53 and 54 are formed in the disk plates 23 and 36, respectively.
By supplying a temperature control medium such as water, oil, or air to the second temperature control flow paths 53, 54, the disc plate 23,
36 is cooled.

Then, in the measuring step, the screw is rotated, the resin is melted and stored in front of the screw, and accordingly, the screw is retracted, and during this period, the mold of the disk molding die is closed. And the mold clamping is performed. Then, in the injection step, the mold is clamped, the screw is moved forward, and the resin stored in front of the screw is injected from the injection nozzle 11 to fill the cavity space C. Then, in the cooling step, the resin in the cavity space C is cooled, punching is performed, and the disk substrate is molded. At this time, the resin remaining in the sprue 29 forms a sprue portion (not shown).

Subsequently, the mold is opened and the mold assembly 32 is opened.
1 is moved backward (moved to the left in FIG. 1), the disk substrate is moved backward while being attached to the disk plate 36, and the sprue portion being held by the cut punch 48. Then, the eject tab bush and the ejector pin are advanced so that the disc substrate and the sprue portion are projected. In this way, the disc substrate is taken out.

By the way, when the mold is opened, the disc substrate and the sprue portion are retracted. At this time, since the temperature of the injection nozzle 11 is set to be equal to or higher than the melting point of the resin, the injection nozzle 11 The resin is melted and cut at the boundary between the injection nozzle 11 and the mold assembly 21.

However, if the temperature of the injection nozzle 11 is set high, the resin may not be cut off at the boundary portion, in which case a stringing phenomenon may occur.

Therefore, in order to supply a cooling gas such as air or an inert gas toward the injection nozzle 11 into the recess 27, the first opening is made on the inner peripheral surface of the recess 27.
Is formed. The first supply passage 61 extends through the sprue bush 26 and the base plate 22 and is communicated with a port 62 formed at a predetermined position of the base plate 22. Further, the port 62 and the pump 63 as a gas supply source are connected via a second supply passage 64, and a control valve 65 is arranged in the second supply passage 64. The first and second supply passages 61 and 64 form a cooling gas supply unit. A control unit 66 is provided to open and close the control valve 65, and the cooling gas is intermittently supplied by the control valve 65. Therefore, the control unit 66 opens the control valve 65 from the time when the mold closing is started to the time immediately before the mold opening is started,
The control unit 66 is closed from when the mold opening is started until immediately before the mold closing is started. Therefore, the cooling gas from the pump 63 is supplied to the first and second supply paths 61 and 6 from the time when the mold closing is started to the time immediately before the mold opening is started.
4 is supplied to the concave portion 27 and the injection nozzle 11 is cooled. Since the portion 68 of the first supply passage 61 that penetrates the sprue bush 26 is formed so as to be inclined toward the opening at the rear end of the sprue 29, the injection nozzle 11
The front end of the sprue 29 and the rear end of the sprue 29 can be intensively cooled.

Therefore, since the stringing phenomenon does not occur when the mold is opened, the disc molding die is not damaged.

It should be noted that the cooling time can be adjusted by adjusting the opening time of the control valve 65 or the opening degree of the control valve 65 according to the set temperature of the injection nozzle 11, the kind of resin, and the like. The cooling capacity by gas can be adjusted. Further, the cooling capacity can be changed by adjusting the temperature of the cooling gas.

FIG. 4 is a sectional view showing a main part of a disk molding machine according to the second embodiment of the present invention.

In the figure, 71 is a fixed platen, 72 is a heating cylinder as a cylinder member, and the injection nozzle 11 is attached to the front end (left end in the drawing) of the heating cylinder 72. The fixed platen 71 is the injection nozzle 1
1 and the through hole 73 for penetrating the heating cylinder 72
The injection nozzle 11 has a
It penetrates through the through hole 73, further through the through hole of the locate ring (not shown), extends forward (to the left in the drawing), and is brought into contact with a sprue bush (not shown).

Further, 75 is arranged along the inner peripheral surface of the through hole 73, and the tip thereof is arranged in the vicinity of the front end of the through hole 73 toward the outer peripheral surface of the injection nozzle 11 and opened. It is a supply path as a cooling gas supply unit provided,
The supply path 75 is connected to a pump (not shown) as a gas supply source. A control valve (not shown) is provided in the supply path 75, and a control unit (not shown) is provided to open and close the control valve. Therefore, the cooling gas is intermittently supplied by the control valve.

The present invention is not limited to the above-mentioned embodiments, but can be variously modified within the scope of the present invention, and they are not excluded from the scope of the present invention.

[0042]

As described above in detail, according to the present invention, in the injection molding machine, the fixed platen, the mold attached to the fixed platen, and the mold are disposed so as to be able to contact the mold. And an injection nozzle for injecting the molding material, and a cooling gas supply unit for supplying the cooling gas toward the injection nozzle.

In this case, since the injection nozzle is cooled by the cooling gas, the stringing phenomenon does not occur when the mold is opened, and the mold device is not damaged.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a main part of a disk molding machine according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a resin stringing phenomenon in a conventional injection molding machine.

FIG. 3 is a sectional view of a sprue bush according to the first embodiment of the present invention.

FIG. 4 is a sectional view showing a main part of a disk molding machine according to a second embodiment of the present invention.

[Explanation of symbols]

11 injection nozzle 21 Mold Assembly 26 Sprue Bush 27 recess 29 sprue 61, 64 First and second supply paths 65 control valve 66 control unit 71 Fixed platen 73 Through hole 75 supply path

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yasushi Odabe             1 731 Naganumahara-cho, Inage-ku, Chiba-shi, Chiba               Sumitomo Heavy Industries, Ltd. Chiba Works (72) Inventor Hiroyuki Sawaishi             1 731 Naganumahara-cho, Inage-ku, Chiba-shi, Chiba               Sumitomo Heavy Industries, Ltd. Chiba Works F-term (reference) 4F206 JA07 JB02 JN06 JQ69 JQ81

Claims (5)

[Claims] 1. (a) a fixed platen; (b) a mold attached to the fixed platen; (d) an injection nozzle disposed so as to be in contact with the mold and capable of injecting a molding material;
(E) An injection molding machine comprising: a cooling gas supply unit that supplies a cooling gas toward the injection nozzle. 2. (a) a sprue bushing that constitutes the mold and has a sprue for passing a molding material injected from the injection nozzle; and (b) the cooling gas supply section, Penetrate the sprue bush,
The injection molding machine according to claim 1, further comprising a supply passage opened on an inner peripheral surface of a recess formed in the sprue bush. 3. The injection molding according to claim 1, wherein the cooling gas supply section is a supply path which is arranged along an inner peripheral surface of a through hole formed in the fixed platen and has an open tip. Machine. 4. The cooling gas is intermittently supplied by a control valve arranged in the supply passage.
The injection molding machine described in 1. 5. The injection molding machine according to claim 4, further comprising a control unit that opens the control valve from when mold closing is started to immediately before mold opening is completed.