JPH0550465A - Injection mold - Google Patents

Abstract

PURPOSE:To constitute the title mold so that restart at the time of a mold change is performed swiftly and automatically, by a method wherein clearances are formed respectively in parts of a confronting and contacting parts between a mounting plate and sprue bushing and between a mold main body and gate bushing. CONSTITUTION:A region corresponding to a part which has been inserted into a mounting plate 14 out of a sprue bushing 15 is not provided and a distance between a hot runner block 20 and nozzle touching face 16 is shortened drastically. Further, the mounting plate 14 and sprue bushing 15 are confronted and brought into contact with each other at one end side and a clearance 21 is formed in one part of a confronting and contacting part. With this construction, a contacting area between the mounting plate 14 and sprue bushing 15 is reduced drastically, consequently, a radiation quantity to the mounting plate 14 from the sprue bushing is reduced drastically. In addition, a band heater 27 which has higher capacity than that of a band heater and is made of aluminum is fitted to the outer circumference of a spacer block 22 in place of the band heater and heating force is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection mold and, more particularly, to a mold capable of effectively melting a resin in a hot runner portion.

[0002]

2. Description of the Related Art An example of a conventionally used injection molding die is shown in FIG. In FIG. 2, an injection molding die 50.
Is a mounting plate 14 provided with a locate ring 12 forming a nozzle receiving portion, a hot runner block 20 for heating the molten resin from the molding machine nozzle, and the mounting plate 14 described above.
And the hot runner block 20, the spool bush 15 for guiding the molten resin to the hot runner block 20, the mold body 30 provided with the cavity 36 corresponding to the product shape to be obtained, and the mold A plurality of (for example, four) gate bushes 32 that are fitted into the mold body 30 and guide the molten resin from the hot runner block 20 to the cavity 36 are interposed between the hot runner block 20 and the gate bush 32. Spacer block 22 for guiding the molten resin from the hot runner block 20 to the gate bush 32
The band heater 25 arranged on the outer periphery of the spacer block 22 and the cavity 3 in cooperation with the mold body 30.
And a core 35 for injection-molding the molten resin in 6.

In such an injection molding die, when the die is changed (at the time of starting) or the like, the hardened resin remains inside (the hot runner portion), so it is necessary to melt it. At this time, since the hot runner block 20 is heated up for about 20 minutes without passing cooling water, the resin inside is not completely melted only by heating up the hot runner block 20, so the nozzle touch surface 16 Is burned with a burner to melt the resin in the spool bush 15, and the band heater 25 is heated. At the same time, the heated rod is inserted into the gate bush 32 and the spacer block 22 from the side of the cavity 36, and the resin there. Is melted and penetrated.

[0004]

However, as described above, when the mold is changed, the work for melting the resin inside is performed manually, so that such work is time-consuming and time-consuming. Is dangerous. Therefore, there is a demand for quick and automatic restart when changing molds.
It is also desired to adapt to this.

In view of the above point, the present invention has an object to provide an injection molding die which can be restarted promptly and automatically at the time of changing the die.

[0006]

In order to achieve the above-mentioned object, an injection molding die according to the present invention basically comprises a mounting plate provided with a nozzle receiving portion and the nozzle receiving portion. A hot runner block that heats the molten resin, a spool bush that is interposed between the mounting plate and the hot runner block to guide the molten resin from the nozzle receiving portion to the hot runner block, and a product shape to be obtained. The mold main body is provided with a corresponding cavity, and the gate bush is fitted into the mold main body and guides the molten resin from the hot runner block to the cavity.

The mounting plate and the spool bush are opposed to each other, and a clearance is formed in a part of the contact portion. Another aspect of the injection molding die according to the present invention is characterized in that a clearance is formed in a part of a contact portion between the die body and the gate bush.

[0008]

In the injection molding die according to the present invention constructed as described above, a part of the contact portion between the mounting plate and the spool bush and a part of the contact portion between the die body and the gate bush are provided. Since the clearance is formed in the core, the contact area between them is greatly reduced, and as a result, the amount of heat radiation from the spool bush to the mounting plate and from the gate bush to the mold body is reduced. Therefore, the internal resin can be melted without relying on human labor, and restart at the time of mold change can be promptly and automatically performed.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a main part of an embodiment of an injection molding die according to the present invention. In FIG. 1, parts corresponding to the parts of the conventional example shown in FIG. The duplicated description thereof will be omitted.

In the embodiment shown in FIG. 1, the height of the spool bush 15 is reduced without providing a portion corresponding to the portion of the spool bush 15 which is fitted into the mounting plate 14 in the conventional example, and the height is reduced. The distance between the runner block 20 and the nozzle touch surface 16 is greatly shortened (about 1/3), and further, the mounting plate 14 and the spool bush 15 are brought into contact with each other at one end side, and a part of the contact portion thereof is provided. A clearance 21 is formed in the.

By doing so, the mounting plate 14
The contact area between the spool bush 15 and
0), resulting in spool bush 1
The amount of heat radiation from 5 to the mounting plate 14 is greatly reduced. Further, instead of the band heater 25, an aluminum band heater 27 having a larger capacity is attached to the outer periphery of the spacer block 22 so as to increase the heating power of this portion.

Further, the mold body 30 and the gate bush 3
Clearance 3 at a part of the contact part with 2 (outer circumference of large diameter part)
1 is formed. Thereby, the gate bush 32
The contact area between the die and the die body 30 is reduced, and the amount of heat radiation from the gate bush 32 to the die body 30 is reduced.

[0013]

As is apparent from the above description, according to the injection molding die of the present invention, a part of the contact portion between the mounting plate and the spool bush, and the pair of the die body and the gate bush. Since a clearance is formed in a part of the contact area, the contact area is greatly reduced, and as a result, the amount of heat radiation from the spool bush to the mounting plate and from the gate bush to the mold body is reduced. To be done. Therefore, the resin inside can be melted without relying on human hands, restarting can be performed quickly and automatically at the time of mold change, and FMS can be realized.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of an embodiment of an injection molding die according to the present invention.

FIG. 2 is a sectional view showing a main part of an example of a conventional injection molding die.

[Explanation of symbols]

 10 ─ Mold for injection molding 14 ─ Mounting plate 15 ─ Spool bush 20 ─ Hot runner block 21, 31 ─ Clearance 30 ─ Mold body 32 ─ Gate bush

Claims (2)

[Claims] 1. A mounting plate provided with a nozzle receiving portion, a hot runner block for heating molten resin from the nozzle receiving portion, and the nozzle which is interposed between the mounting plate and the hot runner block. A spool bush for guiding the molten resin from the receiving portion to the hot runner block, a mold body provided with a cavity corresponding to the product shape to be obtained, and a molten resin from the hot runner block fitted into the mold body In the injection-molding die including a gate bush that guides to the cavity, the mounting plate and the spool bush are brought into contact with each other, and a clearance is formed in a part of the contact portion. And injection mold. 2. A mounting plate provided with a nozzle receiving portion, a hot runner block for heating molten resin from the nozzle receiving portion, and the nozzle interposed between the mounting plate and the hot runner block. A spool bush for guiding the molten resin from the receiving portion to the hot runner block, a mold body provided with a cavity corresponding to the product shape to be obtained, and a molten resin from the hot runner block fitted into the mold body In a mold for injection molding, which comprises a gate bush that guides to the cavity, wherein a clearance is formed in a part of a contact portion between the mold body and the gate bush. Mold.