JPS62233218A - Injection molding equipment - Google Patents

Abstract

PURPOSE:To prevent reliably progress in vulcanization of molten resin which is on standby for injection, by a method wherein a molding tool and nozzle abut against each other in linear contact and the transfer of heat of the molding tool is prevented by separating the nozzle from the molding tool after injection of the molten resin. CONSTITUTION:As a form of a touching part between a nozzle 3 and a top force 32, is linear contact with each other through a seal form 4 based on taper, the heat of the top force 32 is hardly transferred to the nozzle 3. Contact of the nozzle 3 with the top force 32 is prevented by raising the nozzle 3 upward after completion of filling of molten resin. With this construction, the transfere of heat to the nozzle 3 from the top force 32, which is a high-temperature part, is disconnected; therefore, predetermined temperature control of the inside of the nozzle 3, which is a low-temperature part, can be performed smoothly by the temperature of oil flowing through a heating medium oil flow path 2. With this construction, contact time between the top force, which is the high-temperature part and the nozzle, which is the low-temperature part, can be shortened and progress in vulcanization of the molten resin on the inside of the nozzle can be prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an injection molding device, and in particular, to prevent vulcanization from proceeding by preventing heat from acting on molten resin before injection. This invention relates to an injection molding device that can perform

[Prior art and its problems]

Generally, in a molten resin injection molding device that injects molten resin into a mold to obtain a molded product,
It is constructed as shown in FIG.

That is, the nozzle part for storing and injecting molten resin has an inner cylinder 2o and an outer cylinder 21 that fit into each other, and the inner cylinder 20 is screwed into the cylinder 22.
The outer cylinder 21 is provided with a hollow part 24 communicating with the hollow part and containing the injection screw 23, and the outer cylinder 21 is fitted into the inner w120 in a state of threaded engagement at a part in the axial direction. , the upper end surface 25 is brought into pressure contact with the lower end surface of the cylinder 22.

One or more inner cylinders 20 are connected to the hollow part 24,
Preferably, there are three or more material guide holes 26, which communicate with the material guide holes 26, and which are connected to the cylindrical inner circumferential surface 2 of the outer cylinder 21.
a recess 38 that cooperates with 7 to form the fan-shaped flow path 28; and a flow straightening section 30 that cooperates with the truncated conical inner peripheral surface 29 near the end of the outer cylinder 21 and connects to the fan-shaped flow path 28; and rectifier 3
A truncated conical surface 39 forming a slit 31 located at the tip of 0
It is equipped with

When performing molding work using the above-mentioned molding device, a matching circumference made of a truncated conical surface provided on the end surface of the outer cylinder 21 is attached to the mold consisting of the upper mold 32 and the lower mold 33. They are guided by the surfaces 34 and engaged with each other, and the injection side end surface 35 of the outer cylinder 21 is brought into pressure contact with the end surface of the mold so that the central axes are almost coincident, and the injection screw 23 is rotated in the axial direction (as shown in the figure). The molding material in the hollow part 24 (
Molten resin) is forced into a cavity 37 through a narrow gap 31 and a cavity gate 36 to be molded.

The material pressure-fed from the hollow part 24 through the material guide hole 26 is expanded in the circumferential direction by the fan-shaped flow path 28, and furthermore, the flow velocity and flow direction become constant when passing through the rectification part 30. It can be arranged as follows.

In the above operation, a very small gap is maintained between the injection side end face of the inner cylinder 20 and the end face of the mold, and the air in the cabinet is pumped through the gap prior to injection of the material. It is possible to suction using a vacuum pump.

However, in the conventional injection molding apparatus configured as described above, since the nozzle and the touch part of the mold are in plane contact, from the viewpoint of heat transfer, the molten material waiting to be injected inside the nozzle There was a problem in that there was a strong possibility that the resin would cause vulcanization to proceed.

The present invention solves the problems of the prior art as described above, and aims to provide an injection molding apparatus that can reliably prevent the progress of vulcanization of molten resin while waiting for injection. purpose.

Another object of the present invention is to remove, even if the first injected portion of the molten resin to be injected is vulcanized, that portion can be removed without flowing into the cavity. It is an object of the present invention to provide an injection molding device that allows only the portion where sulfur has not progressed to flow into the cavity.

[Means for solving problems]

In order to solve the above-mentioned problems, a first invention provides an injection molding apparatus that injects molten resin into a mold cavity from a nozzle having an injection screw therein to obtain a molded product. When injecting molten resin into the cavity of the mold, which is at a high temperature, the mold and the nozzle come into line contact, and after injecting the molten resin, the nozzle is separated from the mold. This prevents the heat from the mold from being transferred.

Further, a second invention provides an injection molding apparatus configured to inject a molten resin into a mold cavity from a nozzle having an injection screw therein to obtain a molded product.
When injecting molten resin into the cavity of the mold, which is at a high temperature, the mold and the nozzle come into line contact, and after injecting the molten resin, the nozzle is separated from the mold. This prevents heat from the mold from being transferred, and furthermore, during injection, a stagnation system is created to retain the first part of the injected molten resin while the molten resin is injected from the nozzle and reaches the cavity. This method employs a method in which a reservoir is provided in the mold.

[Effect]

By adopting the above-mentioned means, this invention prevents the heat of the molding from acting on the molten resin waiting for injection, so that the vulcanization of the molten resin waiting for injection does not proceed.
Moreover, since the first part of the injected molten resin does not flow into the mold, even if vulcanization progresses, that part can be reliably removed.

〔Example〕

Embodiments of the invention shown in the drawings will be described below.

FIGS. 1 and 2 show an injection molding apparatus according to the present invention, in which members that are substantially the same as those in the conventional apparatus are given the same numbers and their explanations are omitted, but the molds are as follows: The upper die 32, the lower die 33, and the slide core 1 are pressed together (not shown), and the upper die 3;
2, the misaligned nozzle 3 is adapted to touch the lower part of the inner cylinder 20, outer cylinder 21, etc. whose temperature is controlled by oil flowing through the heat medium oil flow path 2 from the upper part.

Then, when this nozzle touch is performed, the cavity 37
Although not shown in the figure, vacuuming is performed.

Thereafter, the injection screw 23 is pushed downward in the axial direction, and the molding material, which is the molten resin in the hollow part 24, is forced into the cavity 37 through the slit 31 and the cavity gate 36, and molding is performed. .

In this case, the shape of the nozzle 3 in contact with the upper die 32 is a tapered seal shape 4,
Since the contact is not a surface contact but a line contact, the amount of heat from the upper die 32 transferred to the nozzle 3 is extremely reduced.

After the injection of the molten resin is completed, the hollow part 24 is filled with the molten resin, and when the position of the injection screw 23 returns to the original position before injection, that is, the upper position, the injection screw 23 enters the hollow part 24. After the filling of the molten resin is completed, the nozzle 3 is moved upward by a predetermined distance as shown in FIG. prevent contact with

As a result, the transfer of heat from the upper die 32, which is a high-temperature part, to the nozzle 3 is cut off, and therefore, the inside of the nozzle 3, which is a low-temperature part, flows through the heat medium oil flow path 2.

The specified temperature can be smoothly controlled at the oil temperature.

Furthermore, the slide core 1 is also raised at the same time during this nozzle back, but the rise of the slide core 1 is stopped when it hits the upper die 32.

Here, the tapered part 5 at the upper part of the slide core 1 closes the separation part flow path between the nozzle 3 and the upper die 32, and
The injected molten resin is compressed toward the inside of the cavity 37, so that a reliable molding operation can be performed.

Regarding the life of each member of the touch part of the nozzle 3 and the upper die 32, the outer cylinder 21 of the nozzle 3 and the counterbore part of the die plate 6 connected to the nameplate 9 via the heat insulating material 10. Since the lowering position of the nozzle 3 is determined by the contact 7, if the dimension of the nozzle 3 is made long enough to fit within the elastic limit of the member strength, the contact part of the nozzle 3 with the upper mold 32 will not be chipped, etc. It is possible to prevent damage to the member.

Also, when the molten resin is injected from the nozzle 3, the cavity 3
The tip of the molten resin flowing into the slide core 7 is in a state where the progress of vulcanization is prevented, but if the vulcanization is progressing, the tip of the molten resin flows into the tapered part 5 and the bottom of the slide core l. The vulcanized portion first flows into the groove 8 formed by the mold 33 and is retained there, so that only the molten resin that has not yet been vulcanized is produced in the cavity 37. It is filled inside.

Therefore, in the structure as described above, since the distance between the nozzle and the cavity is short, the yield rate can be improved, and since the nozzle is separated from the upper mold every time, it is possible to improve the yield rate. The contact time between the upper mold and the nozzle, which is a low-temperature part, can be shortened (this can prevent the progress of vulcanization of the molten resin in the nozzle, and the slide core can be raised when the nozzle is separated from the upper mold). Since it comes into contact with the mold, it is possible to prevent the molten resin from flowing back from inside the mold.

[Effects of the Invention] By having the structure as described above, this invention can prevent the progress of vulcanization of the waiting molten resin, and the first portion of the molten resin to be injected can be prevented from flowing into the cavity. Since only the molten resin that has not been vulcanized is injected into the cavity, it has excellent effects such as ensuring reliable molding work.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the injection molding device according to the present invention in a molding state, FIG. 2 is a sectional view showing the nozzle separated from the mold, and FIG. 3 is a sectional view showing the conventional injection molding device. It is. l...Slide core 2...Taper J Medium oil flow path j (...Nozzle 4...Seal shape 5...Tapered part 6...Gui plate 7...Abutment 8...V groove 9...Nameplate 10...Insulation material 20... ... Inner cylinder 21 ... Outer cylinder 22 ... Cylinder 23 ... Injection screen 24 ... Hollow part 25 ... Upper end surface 26...Material guide hole 27...Cylindrical inner circumferential surface 28...Fan-shaped channel 29...Truncated conical inner circumferential surface 30... ... Rectifying section 31 ... Slit 32 ... Upper mold 33 ... Lower mold; 34 ... Matching peripheral surface 35 ... Injection side end surface;) 6...Cavity gate 37...Cavity 3 (...Recess 39...Truncated conical surface Fig. 1 8■A Procedure NenT official document (spontaneous) 7 August 11, 1985 1.11 deletion - indication Patent application No. 75 of 1985
No. 993 No. 2, Title of the invention Injection molding device 3, Relationship to the case of the person making the amendment Patent applicant address 1-12-15 Shiba Daimon, Minato-ku, Tokyo
No. Name (Name) (438) NOK Co., Ltd. 4, Agent ■102 (Kujira 262-4761)
) Address: 6-8-13, Kudanminami 3-chome, Chiyoda-ku, Tokyo, Subject of amendment: ``Detailed Description of the Invention'' in the specification, Contents of the amendment (11: ``Cabinai'' on page 4, line 16 of the specification) (2) In the same book, page 9, line 17, "molding work will be performed" is corrected to "a compressed filling state will be obtained.".

Claims (2)

[Claims] (1) In an injection molding device that obtains a molded product by injecting molten resin into a mold cavity from a nozzle having an injection screw inside, the inside of the mold cavity is at high temperature. When injecting molten resin, the mold and nozzle come into line contact, and after injecting the molten resin, the nozzle is separated from the mold to prevent heat from the mold from being transferred. An injection molding device characterized by preventing (2) In an injection molding device that obtains a molded product by injecting molten resin into a mold cavity from a nozzle having an injection screw inside, the inside of the mold cavity is at high temperature. When injecting molten resin, the mold and nozzle come into line contact, and after injecting the molten resin, the nozzle is separated from the mold to prevent heat from the mold from being transferred. In addition, the mold is provided with a retention portion that retains a first portion of the injected molten resin while the molten resin injected from the nozzle reaches the cavity during injection. Injection molding equipment.