JPH07178773A - Stringing preventing device of injection mold using hot runner - Google Patents

Abstract

PURPOSE:To easily divide a resin at a boundary part and to prevent the stringing of an injection mold. CONSTITUTION:A stringing preventing device consists of the hot runner block 2 arranged so as to be allowed to face to the nozzle 1 of an injection molding machine, the hot runner nozzle 3 arranged to the hot runner block 2, the spool 5 arranged in an injection mold 4 so as to be allowed to face to the hot runner nozzle 3 and the traverse plate member 6 arranged in the direction traversing the axis of the molten resin passage 52 provided to the upper part of the spool 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a yarn pulling prevention device for an injection molding die which uses a hot runner arranged so as to face a nozzle of an injection molding machine.

[0002]

2. Description of the Related Art A conventional injection molding nozzle (actual flat blade 4-96314) equipped with a stringing prevention mechanism has a baffle plate P in an injection hole H at the tip of a nozzle N of an injection molding machine as shown in FIG. The baffle plate P disposed in the nozzle N causes the resin to be in a state in which the axial center portion is missing at the contact portion between the tip of the nozzle N and the end surface of the spool S, and near the inlet of the spool S. The mold opening is performed in a completely solidified state, which prevents the occurrence of string pulling.

A conventional threading prevention device for an injection molding die (actual opening flat 5-39925) has a nozzle N of an injection molding machine in a spool S of an injection molding die K as shown in FIGS. 12 and 13. A baffle plate P that faces the axial center of the spool S is disposed in the flow path of the molten resin so as to face the resin, and the resin is caused by the baffle plate P disposed on the spool S and the tip of the nozzle N and the spool S. The axial center portion is lost at the contact portion with the end surface of the spool S, and the mold opening is performed in a state where the spool S is completely solidified in the vicinity of the inlet thereof, which prevents the occurrence of stringing.

[0004]

In the conventional injection molding nozzle described above, since the baffle plate P is disposed in the injection hole H at the tip of the nozzle N of the injection molding machine, injection molding using a hot runner is performed. There was a problem that it could not be applied to the mold.

Further, in the above-mentioned conventional yarn drawing prevention device for an injection molding die, in the spool S of the injection molding die K, the spool S of the spool S is made to face the nozzle N of the injection molding machine so as to face the nozzle N of the injection molding machine. Since the baffle plate P that traverses the axis is arranged, there is a problem that it cannot be applied to an injection molding die that uses a hot runner as described above.

Therefore, the inventor of the present invention has found a direction transverse to the axis of the flow path of the molten resin at the boundary between the hot runner nozzle and the spool arranged in the hot runner block arranged facing the nozzle of the injection molding machine. In addition to focusing on the technical idea of the present invention of disposing a cross member on the inner side, a gap is formed between the lower end of the hot runner nozzle and the upper end of the spool to promote the separation of the resin during mold opening. As a result of further research and development focusing on the technical idea of the invention, a book that achieves the purpose of facilitating resin separation at the time of mold opening of an injection molding die using a hot runner and preventing stringing. The invention was reached.

[0007]

A yarn drawing prevention device for an injection molding die using a hot runner according to the present invention (the first invention according to claim 1) is arranged facing a nozzle of an injection molding machine. A hot runner block, a hot runner nozzle arranged in the hot runner block, a spool arranged in the injection mold facing the hot runner nozzle, and a boundary portion between the hot runner nozzle and the spool And a transverse member arranged in a direction transverse to the axis of the molten resin flow path.

A thread pulling prevention device for an injection molding die using a hot runner according to the present invention (a second invention according to claim 2) is the same as in the first invention, wherein the lower end of the hot runner nozzle and the upper end of the spool are provided. And a cross member is arranged at the upper end of the spool downstream of the gap.

According to a second aspect of the present invention, there is provided a threading prevention device for an injection molding die using a hot runner according to the third aspect of the present invention. The inner wall of the flow passage is formed in a tapered shape over a range longer than the length of the transverse member in the flow passage direction.

[0010]

According to the first aspect of the present invention having the above-mentioned structure, the device for preventing stringing of the injection molding die using the hot runner is configured such that the molten resin supplied from the nozzle of the injection molding machine is passed through the hot runner block to the hot runner nozzle. Is supplied to the hot runner nozzle and the spool of the injection mold, and the molten resin passes through the spool after the molten resin is branched in a state of being branched between the cross member and the flow path of the molten resin. And is supplied into the injection molding die to divide the resin at the boundary portion where the cross member is arranged when the injection molding die is opened.

In the yarn pulling prevention device for the injection molding die using the hot runner according to the second aspect of the present invention, a gap having a large cross section is formed between the lower end of the hot runner nozzle and the upper end of the spool. The molten resin that has passed is
After passing in a state of being branched by a branch passage having a small cross-sectional area formed between the cross member arranged at the upper end of the spool of the injection molding die downstream of the gap and the flow passage of the molten resin The resin is supplied through the spool into the injection molding die to divide the resin at the boundary portion where the transverse member is arranged when the injection molding die is opened.

According to a third aspect of the present invention having the above-described structure, the yarn pulling prevention apparatus for the injection molding die using the hot runner has a structure in which the molten resin passed through a gap formed between the lower end of the hot runner nozzle and the upper end of the spool. Is passed through in a branched state between the cross member arranged at the upper end of the spool of the injection mold downstream of the gap and the tapered flow path of the molten resin, and then injected through the spool. The resin is supplied into the molding die and the resin is divided at the boundary portion where the cross member is arranged when the injection molding die is opened.

[0013]

According to the first aspect of the present invention, there is provided a yarn pulling prevention device for an injection molding die using the hot runner, which is arranged at a boundary portion between the hot runner nozzle and the spool of the injection molding die. Since the molten resin is allowed to pass through in a state where the branched member is branched between the transverse member and the flow path of the molten resin and the axial center is missing, when the mold of the injection molding die is opened, the resin is removed at the boundary portion where the transverse member is arranged. The effect of easily separating and preventing stringing of the injection molding die is exhibited.

In the yarn pulling prevention device for the injection molding die using the hot runner of the second aspect of the present invention, a large cross-sectional area gap is formed between the lower end of the hot runner nozzle and the upper end of the spool. The molten resin that has passed through
Since it is branched by a branch passage having a small cross-sectional area formed between the cross member arranged at the upper end of the spool of the injection molding die and the flow passage of the molten resin, the passage is made in a state where the axial center is missing, When the mold of the injection molding die is opened, the cross-sectional area is sharply reduced at the upper end of the spool in which the transverse member is arranged, and solidification of the resin in the thickness direction is promoted.
When the resin is completely solidified, the resin can be more easily divided and the stringing of the injection molding die can be effectively prevented.

In the yarn pulling prevention apparatus for the injection molding die using the hot runner of the third aspect of the present invention, a large cross-sectional area gap is formed between the lower end of the hot runner nozzle and the upper end of the spool. The molten resin that has passed through
Since it is branched by a branch passage having a small cross-sectional area formed between the transverse member arranged at the upper end of the spool of the injection molding die and the tapered flow passage, it is passed in a state where the axial center is missing. When the injection molding die is opened, the resin is more easily divided by further reducing the cross-sectional area at the upper end of the spool on which the transverse member is arranged, and the threading of the injection molding die is performed. The effect of more effectively preventing is exhibited.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) As shown in FIG. 1, a threading prevention device for an injection molding die using a hot runner according to the first embodiment is a hot runner arranged so as to face a nozzle 1 of an injection molding machine. Block 2, hot runner nozzle 3 arranged in the hot runner block 2, spool 5 arranged in the injection molding die 4 facing the hot runner nozzle 3, and melting of the upper end of the spool 5 A transverse plate member 6 arranged in a direction transverse to the axis of the resin flow path 52.
It consists of and.

As shown in FIG. 1, the hot runner block 2 has a flow path 21 for molten resin extending in the left-right direction in the block main body 20 and an inlet flow path communicating with the nozzle 1 of the injection molding machine 1. 22 and the hot runner nozzle 3
An outlet passage 23 communicating with the cartridge heater 24 is formed, and a cartridge heater 24 is arranged in parallel in the left-right direction in the drawing so that the passing molten resin can be set to a high temperature.

As shown in FIG. 1, the hot runner nozzle 3 is composed of a hollow cylindrical body 30 having a flange portion 31 fixed to the hot runner block 2 at an upper end thereof, and band heaters 32 are wound up and down. A temperature sensor 33 is provided between the upper and lower band heaters 32 to control the temperature inside the nozzle, and has a large-diameter flow passage 34 in the center that communicates with the outlet flow passage 23 of the hot runner block 2. A small-diameter flow path 35 that connects to the spool 5 and supplies the molten resin is formed in series at the lower portion thereof. A circular protrusion 36 having a constant length is formed at the lower end of the hollow cylindrical body 30.

As shown in FIGS. 1 to 4, the spool 5 comprises a spool bush type hollow cylindrical body 50 having a flange portion 51 abutting against the lower end of the hot runner nozzle 3 at the upper end thereof, and an axial center portion thereof. A molten resin flow path 52 is coaxially formed in and is disposed above the injection molding die 4.

At the center of the upper surface of the flange 51, a circular recess 511 is formed, which is deeper than the length of the protrusion 36 into which the protrusion 36 at the lower end of the hot runner nozzle 3 is inserted, by a predetermined length. When the spool 5 comes into contact with the hot runner nozzle 3, a constant gap 5G (for example, 0.3 mm) is formed.

The diameter of the upper end opening of the flow path 52 formed in the spool 5 is set to 6 mm, and the tapered inner wall portion 521 is formed over the length of 5 mm in the axial direction. The diameter of the diameter part is set to 8 mm.

As shown in FIGS. 2 and 4, the transverse plate member 6 is composed of a plate member having a plate thickness of 2 mm and a width of about 3 mm, and is disposed so as to penetrate the flange portion 51 of the spool 5, and 5 in the tapered inner wall portion 521
The flow path 52 is divided into two flow paths 522 and 523 such that the flow path 52 is crossed so as to pass through the axis.

In the yarn pulling prevention apparatus for the injection molding die using the hot runner of the first embodiment having the above-mentioned structure, the molten resin injected from the nozzle 1 of the injection molding machine is the inlet flow path of the hot runner block 2. 22 is supplied to the flow path 21 heated by the cartridge heater 24 from the nozzle 22 and is supplied to the hot runner nozzle 3 via the outlet flow path 23, and is heated by the band heater 32 of the hot runner nozzle 3. The molten resin supplied from the flow path 34 to the small-diameter flow path 35, injected from the outlet of the small-diameter flow path 35 into the flow path 52 of the flange portion 51 of the spool 5, and supplied to the flow path 52 is described above. It is branched by the transverse member 6 and is branched and supplied to the flow passages 522 and 523. After passing through the transverse plate member 6, it is merged again and supplied into the flow passage 52. Filling is supplied to the mold 4.

In the apparatus of the first embodiment, the molten resin injected into the flow path 52 of the flange portion 51 of the spool 5 is branched by the transverse plate member 6 and the flow path 522 is formed.
And 523 are divided and supplied, so that the axial center portion of the flow path 52 is omitted, so that the flange portion 5 of the spool 5 is
The resin in 1 is opened in a completely solidified state, and the resin in the spool 5 is cut at the boundary between the hot runner nozzle 3 and the spool 5.

In the device of the first embodiment having the above-described action, the molten resin injected into the flow path 52 of the flange portion 51 of the spool 5 is branched by the transverse plate member 6, so that the flow path 52 The resin in the flange portion 51 of the spool 5 has a shape in which the resin is missing at the axial center portion, and the resin in the melted small-diameter flow path 35 and the resin in the solidified flow path 52 form a protrusion 36. Since the mounted transverse plate member 6 is opened in a completely solidified state in order to promote solidification of the resin, there is an effect that stringing is prevented.

In the first embodiment, the gap 5G is formed between the circular recess 511 formed at the inlet of the flange 51 of the spool 5 and the circular protrusion 36 of the hot runner nozzle 3. Since molten resin is filled in the gap 5G, the gap 5G is formed when the mold is opened.
The molten resin filled therein acts as a stopper, and a stress concentration portion is formed at a portion where the molten resin portion filled in the gap 5G is transferred to the inlet of the flow passage 52 of the flange portion 51 of the spool 5. As a result, it is possible to further facilitate the cutting of the resin and to prevent stringing. Further, since the filled gap 5G is formed in a thin film shape, it can be easily broken by the internal pressure at the time of resin injection at the time of the next molding.

Further, in the apparatus of the first embodiment, since the inner wall of the flow path 52 in which the transverse plate member 6 is arranged is a tapered surface having a larger angle (for example, 90 degrees) than the inner wall downstream thereof, In order to further promote the concentration of stress in the inlet portion of the flow path 52 of the flange portion 51 of the spool 5, it is possible to further facilitate resin cutting, prevent stringing, and dispose the transverse plate member 6. It is possible to prevent an increase in the resistance of the flow of the flow path 52, abnormal acceleration of the solidified state due to the decrease in the flow path area, or a decrease in the resin inflow amount due to the decrease in the flow path, which causes the inlet port to be clogged and cause other problems. It has the effect of preventing it.

That is, the conventional spool arranged so as to face the hot runner nozzle is shown in FIGS.
As shown in FIG. 5, the inlet of the spool S is composed of a small-diameter portion I having the same diameter as the outlet of the hot runner nozzle, and a flow path is used downstream of the small-diameter portion to rapidly increase the diameter. Therefore, the stringing of the resin was likely to occur during mold opening.

In the first embodiment, the small diameter portion having the same diameter as the outlet portion of the conventional hot runner nozzle is eliminated, and not only the conventional cause of stringing is eliminated but also the transverse plate member 6 is arranged. Therefore, by increasing the inner diameter of the inlet portion of the spool and forming the taper portion, the resistance of the resin flow is reduced even when the transverse plate member 6 is arranged, and the resin flow in the flow path is reduced. Has the effect of improving.

(Second Embodiment) As shown in FIG. 5, a yarn pulling prevention device for an injection molding die using a hot runner according to a second embodiment has a structure in which the transverse plate member 6 of the first embodiment is partially bushed. 61, a movable mold 7 corresponding to the tip of the spool 5.
It has the same function and effect as the first embodiment.

(Third Embodiment) As shown in FIGS. 6 and 7, the yarn pulling prevention apparatus for the injection molding die using the hot runner according to the third embodiment has the hot runner nozzle 3 facing the spool 5 as shown in FIGS. A transverse plate member 62 similar to that of the first embodiment is arranged at the outlet portion 37 of the small diameter passage at the lower end of the above, and a gap of 0.2 to 0.3 mm is provided between the spool 5 and the spool 5 in consideration of thermal expansion of the nozzle portion. Formed in the first
The same operation and effect as those of the embodiment are exhibited.

(Fourth Embodiment) As shown in FIGS. 8 and 9, a yarn pulling prevention device for an injection molding die using a hot runner according to a fourth embodiment has a pin shape as a transverse member at the tip of the spool 5 as shown in FIGS. Since the member 63 is provided, the same effect as that of the first embodiment is obtained, and since the cross member is constituted by the pin-shaped member 63, the resistance is reduced when the resin is cut, and the generation of chips is prevented. However, it is possible to reduce the number of assembling and finishing steps, and it is possible to improve the performance and reduce the cost.

(Fifth Embodiment) As shown in FIG. 10, a threading prevention device for an injection molding die using a hot runner according to a fifth embodiment has a streamlined member as a transverse member at the tip of the spool 5, as shown in FIG. In addition to providing the same effects as those of the first embodiment, the cross member is constituted by a streamlined member 64, and the streamlined shape is oriented in the resin inflow direction and the cutting direction. Therefore, it is possible to reduce the flow resistance of the molten resin, prevent the generation of chips, and improve the performance.

The embodiments described above are merely examples for the purpose of explanation, and the present invention is not limited to them. Those skilled in the art will recognize from the claims, the detailed description of the invention and the description of the drawings. Modifications and additions can be made without departing from the technical idea of the present invention.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment device of the present invention.

FIG. 2 is a vertical cross-sectional view showing a spool and a cross member of the first embodiment.

FIG. 3 is a plan view showing a spool and a cross member of the first embodiment.

FIG. 4 is a partially enlarged cross-sectional view showing an arrangement relationship of a hot runner nozzle, a spool and a cross member according to the first embodiment.

FIG. 5 is a cross-sectional view showing a second embodiment device of the present invention.

FIG. 6 is a cross-sectional view showing a third embodiment device of the present invention.

FIG. 7 is a partially enlarged cross-sectional view showing an arrangement relationship between a hot runner nozzle, a spool and a cross member according to a third embodiment.

FIG. 8 is a vertical sectional view showing a spool and a cross member of a fourth embodiment.

FIG. 9 is a vertical cross-sectional view showing a spool and a cross member of a fourth embodiment with different cross sections.

FIG. 10 is a vertical sectional view showing a spool and a cross member of a fifth embodiment.

FIG. 11 is a partial vertical cross-sectional view showing an injection molding nozzle provided with a conventional baffle plate.

FIG. 12 is a vertical cross-sectional view showing a spool in which a conventional baffle plate is arranged.

FIG. 13 is a cross-sectional view showing a spool having a conventional baffle, an injection molding nozzle, and an injection mold.

FIG. 14 is a vertical cross-sectional view showing a spool used to face a conventional hot runner nozzle.

FIG. 15 is a plan view showing a spool used to face a conventional hot runner nozzle.

[Explanation of symbols]

 1 Nozzle 2 Hot Runner Block 3 Hot Runner Nozzle 4 Injection Mold 5 Spool 6, 62 Cross Plate Member 7 Movable 61 Bush 63 Pin-shaped Member 64 Streamlined Member

Claims (3)

[Claims] 1. A hot runner block arranged facing a nozzle of an injection molding machine, a hot runner nozzle arranged in the hot runner block, and a hot runner block arranged in an injection molding mold facing the hot runner nozzle. Injection using a hot runner, characterized in that it comprises a spool provided and a crossing member arranged in a direction crossing the axis of the flow path of the molten resin at the boundary between the hot runner nozzle and the spool. A device for preventing string pulling of the molding die. 2. The gap according to claim 1, wherein a gap is formed between the lower end of the hot runner nozzle and the upper end of the spool, and the transverse member is arranged at the upper end of the spool downstream of the gap. Thread pull prevention device for injection molds using a hot runner. 3. The molten resin flow path inner wall of the spool, on which the cross member is disposed, is formed in a tapered shape over a range longer than a length of the cross member in the flow path direction. A thread pull prevention device for injection molds that uses a hot runner.