JP2000246766A - Manufacture of injection holding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a molding cycle without increasing robot arms. SOLUTION: A fixed side mold 1, a stripper plate 2 and a movable side mold 3 are sequentially provided in this order. An injection mold is provided with a cavity 4 corresponding to a shape of a molding 42 to be molded between the plate 2 and the mold 3 in the closed mold state. A resin is injected in the cavity 4 from resin channels 5, 6 and 7 formed from the mold 1 through the plate 2, cooled to be solidified, and then the mold is opened, the injection molding 42 is taken out and the resin solidified in the channels 5, 6 and 7 is removed by spraying compressed air from a resin channel inlet side 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing an injection molded article.

[0002]

2. Description of the Related Art Conventionally, a sleep rate type has been frequently used because it is easy to cut a gate and it is easy to separate a molded product from a solidified resin filled in a sprue, a runner, a gate, and the like, and to take out the molded product. I have.

[0003] As an example of this, a case of molding a cylindrical molded product will be described with reference to Figs. FIG. 3 is a sectional view showing a closed state of a sleep rate type mold for molding the cylindrical molded product, and FIGS. 4 and 5 show an open state of the sleep rate type. As shown in FIG. 3, a sleep rate mold for molding a cylindrical molded product is provided with a fixed mold a, a stripper plate b, and a movable mold c in this order. A cavity d corresponding to the outer surface shape of the cylindrical molded product is provided between the mold and the mold c, and a side core e corresponding to the inner surface shape of the cylindrical molded product is provided in the cavity d.

In order to form a cylindrical molded product by the sleep rate type, first, a resin is injected into a cavity d from a nozzle of an injection molding machine (not shown) via a sprue f, a runner g, and a gate h. When the injection is completed and the resin is solidified, the movable mold c is retracted along the guide pins (i in FIG. 4). As a result, the parting line (PL
The mold is divided at 3), the resin is cut at the gate h, and the cylindrical molded product d1 is left on the movable mold c side.

[0005] On the other hand, after the retreat of the movable mold c is started, the stripper plate b is moved by a not-shown spline.
It is divided at the fixed mold a and the parting line (PL4) and retreats. At this time, the resin j filled in the sprue f, the runner g, and the gate h is left on the fixed mold a side.

Next, the cylindrical molded product d1 is detached from the movable mold c by the claw k1 of the robot arm k to obtain a product. Thereafter, the resin j filled in the sprue f, the runner g, and the gate h is similarly processed. And the robot arm k is detached from the fixed mold a by the claw k1.

[0007]

However, according to the above method, after the cylindrical molded product d1 is removed from the movable mold c by the robot arm k, the robot arm k is moved and the sprue f, the runner g, Two steps of removing the resin j filled in the gate h from the fixed mold a were required, which led to the extension of the molding cycle. Although it is possible to provide two robot arms, there is a problem in that the capital investment for that purpose is expensive.

An object of the present invention is to solve the above-mentioned problems and to provide a method of manufacturing an injection-molded article capable of shortening a molding cycle without increasing the number of robot arms.

[0009]

According to a method of manufacturing an injection-molded article of the present invention, a fixed mold, a stripper plate, and a movable mold are provided in this order. Between the movable mold and the injection mold provided with a cavity corresponding to the shape of the molded product to be molded, from the fixed mold to the resin flow path formed through the stripper plate By injecting the resin into the cavity, cooling and solidifying, then opening the mold, taking out the injection molded product, and blowing the resin solidified in the resin flow path from the resin flow path entrance side with compressed air, It is to be removed.

The resin used in the present invention is not particularly limited as long as it is a resin usually used for injection molding. For example, polyethylene, polypropylene, polyvinyl chloride,
Thermoplastic resins such as polyvinylidene fluoride; thermosetting resins such as unsaturated polyester;

(Operation) In the method of manufacturing an injection-molded article of the present invention, a fixed mold, a stripper plate, and a movable mold are provided in this order, and in a closed state, the stripper plate and the movable mold are closed. From the fixed side mold of the injection mold having a cavity corresponding to the shape of the molded article to be molded between the mold and the resin, the resin is supplied from the resin flow path formed through the stripper plate. Injects into the cavity, cools and solidifies, opens the mold, removes the injection molded product, and removes the resin solidified in the resin flow path by blowing compressed air from the resin flow path entrance side. Therefore, the molded product as a product is taken out without being damaged, and the resin solidified in the resin flow path may be damaged, so that it is removed and discarded as it is.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below.
This will be described in detail with reference to the drawings. FIG. 1 is a sectional view showing a closed state of an injection mold (sleep rate mold) that can be used in the method of manufacturing an injection molded article of the present invention, and FIG. 2 is an open state of the injection mold. Is shown. As shown in FIG. 1, an injection mold for molding a cylindrical molded product includes a fixed mold 1, a stripper plate 2, and a movable mold 3, which are provided in this order. A cavity 4 corresponding to the outer surface shape of the cylindrical molded product is provided between the side mold 3 and the side core 42 corresponding to the inner surface shape of the cylindrical molded product. Further, a compressed air passage 8 for supplying compressed air from a compressor (not shown) is provided on the inlet side of the resin flow path (sprue 5). A valve pin (not shown) is provided.

In order to form a cylindrical molded product using the injection mold, the compressed air passage 8 is first shut off by a valve pin (not shown), and then a resin flow is injected from a nozzle of an injection molding machine (not shown). The resin is injected into the cavity 4 through a path (sprue 5, runner 6, gate 7). When the injection is completed and the resin is solidified, the movable mold 3 is retracted along the guide pins (9 in FIG. 2). As a result, the mold is divided at the parting line (PL1), the resin is cut at the gate 7, the cylindrical molded product 44 is left on the movable mold 3 side, and the limit provided on the movable mold 3 is set. A signal for opening a valve pin (not shown) is sent by a switch (not shown), and the compressed air passage 8 is opened.
Compressed air is sent to

On the other hand, after the movable-side mold 3 starts retreating, the stripper plate 2 is moved by a not-shown projection.
It is divided by the fixed mold 1 and the parting line (PL2) and retreats. At this time, the resin 61 filled in the resin flow path (the sprue 5, the runner 6, and the gate 7) is left on the fixed mold 1 side.

Next, the cylindrical molded product 44 is removed from the movable mold 3 by the claws 101 of the robot arm 10 to form a product. On the other hand, compressed air is sent to the compressed air flow path 8, and the sprue 5, the runner 6. The compressed air blown into the gate 7 removes the resin 61 and drops the resin 61 below the injection mold. At this time, a photoelectric tube 62 is provided below the injection molding die, and the drop of the resin 61 is confirmed. At this time, if the drop of the resin 61 is not confirmed even after the lapse of a predetermined time, an alarm is issued and the molding machine is stopped. When the resin 61 is confirmed to have fallen, the injection molding die is closed, the valve pin (not shown) of the compressed air passage 8 is closed, and the process proceeds to a normal molding process.

[0016]

The method of manufacturing an injection-molded article according to the present invention is as described above, so that the molding cycle can be shortened without increasing the number of robot arms.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a closed state of an injection mold that can be used in the method of manufacturing an injection-molded article of the present invention. It is sectional drawing which shows an example of the state before joining.

FIG. 2 is a sectional view showing a state in which the injection mold of FIG. 1 is opened.

FIG. 3 is a cross-sectional view showing a closed state of an injection mold that can be used in a conventional method of manufacturing an injection molded product.

FIG. 4 is a cross-sectional view showing a state before the injection-molding mold of FIG. 3 is opened and a molded product is taken out.

FIG. 5 is a cross-sectional view showing a state after a molded product is taken out from the injection mold of FIG. 3;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 fixed mold 2 stripper plate 3 movable mold 4 cavity 42 side core 44 columnar molded product 5 sprue 6 runner 61 resin filled in resin flow path 7 gate 8 compressed air passage

Claims (1)

[Claims] 1. A fixed mold, a stripper plate,
The movable mold is provided in this order, and in a closed state, between the stripper plate and the movable mold, a cavity corresponding to the shape of the molded article to be molded is provided. From the fixed mold, the resin is injected into the cavity from the resin flow path formed through the stripper plate, cooled and solidified, then opened, and the injection molded product is taken out and solidified in the resin flow path. A method of manufacturing an injection-molded article, characterized in that the blown resin is removed by blowing compressed air from an inlet side of the resin flow path.