JP2003165149A - Method and apparatus for injection molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enough pack a resin even in a thin-wall part in an injection molding method and in an injection molding apparatus. <P>SOLUTION: The injection molding apparatus has mold bodies 2 and 3 which are mutually openable/closable and form a cavity 1 between them when a mold is closed and produces a molding having the thin-wall part by the mold bodies. The mold body has a core mold 3a which constitutes at least a part of a part 1a to be provided to the thin-wall part of the cavity and can move. An injection mechanism 11 for injecting the molten resin into the cavity and a core moving mechanism 12 for moving the core mold toward the inside of the cavity while the resin is injected into the cavity are provided. <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 apparatus and an injection molding method for a molded product having a thin portion.

[0002]

2. Description of the Related Art In recent years, various memory cards having a built-in semiconductor memory as a small-sized storage medium have been developed and used in many electronic device devices. This memory card has a nonvolatile semiconductor memory sandwiched between a resin-molded upper body and a lower body, and is housed inside, and a recess is formed in the upper body and the lower body to house the semiconductor memory. There is.

The memory card is thin and lightweight as a whole, and in the upper body and the lower body, the concave portion for accommodating the semiconductor memory is a thin portion which is thinner than the other thick portions. . The upper body and the lower body of these memory cards are manufactured by injection molding. Conventionally, when a resin product having a thin wall portion is manufactured by injection molding, a cavity corresponding to a molded body having a desired thin wall portion is formed between molds that can be opened and closed, and a molten resin is filled in the cavity. It is filled and injection molded.

[0004]

However, the above-mentioned conventional injection molding technique has the following problems. That is, when molding a molded product having a thin portion such as a memory card, there is a disadvantage that the injected molten resin is not easily filled in the thin portion.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an injection molding apparatus and an injection molding method capable of sufficiently filling a thin portion with resin.

[0006]

The present invention has the following features to attain the object mentioned above. That is, the injection molding apparatus of the present invention is an injection molding apparatus that includes a plurality of mold bodies that can be opened and closed and that form a cavity between the mold bodies when they are closed, and that manufactures a molded product having a thin portion with these mold bodies. The mold body includes a movable core mold that constitutes at least a part of a portion of the cavity provided for the thin portion, and an injection mechanism that injects a molten resin into the cavity, and the resin. And a core moving mechanism for moving the core mold toward the inside of the cavity during the injection.

Further, the injection molding method of the present invention is an injection molding method for producing a molded article having a thin portion by using a plurality of mold bodies which can be opened and closed and which form a cavity between them when the molds are closed. The mold body comprises a movable core mold that constitutes at least a part of a portion of the cavity provided for the thin portion, and has an injection step of injecting the molten resin into the cavity. The injection process
The core mold is moved toward the inside of the cavity while the resin is being injected into the cavity.

In these injection molding apparatus and injection molding method, since the core mold is moved toward the inside of the cavity while the resin is being injected into the cavity, it is provided to the thin portion immediately after the injection of the resin is started. The opening area of the part is wide, and the resin is smoothly injected.In addition, during the injection, the resin injected by the movement of the core mold is pushed in the part to be supplied to the thin part, the flow velocity is increased, and it is supplied to the thin part. The part to be filled can be fully filled. The present invention is to move the core mold to a predetermined position while the resin is being injected, and to move the core mold in a state where the resin is completely filled to compress the resin. Unlike, the thin section is not particularly compressed.

Further, in the injection molding apparatus of the present invention, the molded product is at least one of an upper body and a lower body of a memory card which is housed inside with a semiconductor memory interposed therebetween, and a portion provided for the thin portion is The present invention is suitable for a technique which is a portion provided in a recess for accommodating the semiconductor memory in the upper body and the lower body.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an injection molding apparatus and an injection molding method according to the present invention will be described below with reference to FIGS. 1 to 3.

The injection molding apparatus in this embodiment is for molding the lower body of a memory card with resin, and as shown in FIG. 1 and FIG. A fixed mold (mold body) 2 and a movable mold (mold body) 3 that form a cavity 1 therein; an injection mechanism 11 such as an injection molding machine that injects a molten thermoplastic resin R into the cavity 1; The movable mold drive mechanism (core moving mechanism) 12 such as a hydraulic mechanism for moving the movable mold 3 forward and backward is provided. Further, as shown in FIG. 3, the lower body (molded product) 4 of the memory card to be molded has a thick portion 4a and a thin portion 4b having different thicknesses, and the thin portion 4b is provided with a semiconductor memory. A recess for accommodating is formed. The thin portion 4b has a thickness of 0.35 mm, for example.

The injection mechanism 11 is for injecting the molten resin R into the cavity 1 from the gate 5 through the sprue 7 and the runner 6. The movable mold 2 includes a core mold 3a that constitutes one surface of a portion 1b provided for the thin portion 4b of the cavity 1 and is movable in the mold closing direction. In addition, in the movable drive mechanism 12, the resin R has the cavity 1
It is set to move the core mold 3a toward the inside of the cavity while being injected into the inside.

Next, an injection molding method of the lower body 4 using this injection molding apparatus will be described.

At the time of molding, the movable die driving mechanism 12 closes the fixed die 2 and the movable die 3 to form the cavity 1, and the sprue 7 is connected to the runner 6 of the gate 5. At this time, the movable die drive mechanism 12 causes the core die 3 to move.
a is retracted from the desired position, and the thickness of the portion 1a provided for the thin portion 4b is made wider than the desired thin portion 4b. In this state, the injection mechanism 11 injects the molten resin R as a molding material into the cavity 1 from the sprue 7 via the runner 6 and the gate 5.

At this time, immediately after the resin R is injected into the cavity 1, as shown in FIG. 1, since the opening area of the portion 1a provided for the thin portion 4b is large, the resin smoothly flows in. Furthermore, as shown in FIG. 2, the resin R is injected into the cavity 1 by the movable drive mechanism 12 after an extremely short time (for example, about several hundredths of a second) from the start of the inflow of the resin R. In the middle, the core mold 3a is moved toward the inside of the cavity 1 to a predetermined position. At this time, the thin portion 4
In the portion 1a provided for b, the resin R injected by the movement of the core mold 3a is pushed to increase the flow velocity, and the thin portion 4
The portion 1a provided for b can be sufficiently filled.
Note that the resin R in the cavity 1 is not compressed because the core mold 3a is moved during the injection, not when the filling of the resin R is completed.

After the resin R filled in the cavity 1 is solidified, the fixed mold 2 and the movable mold 3 are opened by the movable mold driving mechanism 12 to solidify the resin in the cavity 1. The lower main body 4 is manufactured by projecting R, that is, a molded product with a projecting pin (not shown) and taking it out of the movable mold 3.

The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the above embodiment is applied to the injection molding apparatus and the injection molding method for molding the lower body of the memory card.
It may be applied to a technique for molding the upper main body of the memory card, or may be applied to a technique for molding another molded product having a thin portion.

[0018]

The present invention has the following effects.
That is, according to the injection molding apparatus and the injection molding method of the present invention, the core mold is moved toward the inside of the cavity while the resin is being injected into the cavity. The opening area of the part to be filled is wide, and the resin is smoothly injected. Furthermore, during the injection, the resin injected by the movement of the core mold is pushed in the part to be supplied to the thin part, and the flow velocity is increased. It is possible to fully fill the part to be used for. Therefore, it is possible to obtain a good molded product without insufficient filling in the thin portion, which is particularly suitable for molding a memory card.

[Brief description of drawings]

FIG. 1 is a sectional view of essential parts showing a fixed mold and a movable mold immediately after resin injection in an embodiment of an injection molding die according to the present invention.

FIG. 2 is a sectional view of essential parts showing a fixed mold and a movable mold at the time of completion of resin filling in an embodiment of an injection molding die according to the present invention.

FIG. 3 is a plan view showing a lower main body of a memory card in an embodiment of an injection molding die according to the present invention and its A-
It is an A line arrow sectional view.

[Explanation of symbols]

1 cavity 2 Fixed type (type body) 3 Movable type 3a core type 4 Lower body of memory card (molded product) 4a thick part 4b Thin part 5 gates 11 injection mechanism 12 Movable drive mechanism (core moving mechanism) R resin

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4F202 CA11 CB01 CK18 CK52                 4F206 JA07 JM04 JM05 JN25 JN32                       JQ81                 5F061 AA01 BA01 CA21 DA06 FA03

Claims (3)

[Claims] 1. An injection molding apparatus comprising a plurality of mold bodies which can be opened and closed and which form cavities between them when the molds are closed, and which manufactures a molded product having a thin portion with the mold bodies. Includes a movable core mold that constitutes at least a part of a portion of the cavity provided for the thin portion, and an injection mechanism that injects a molten resin into the cavity, and the resin is injected into the cavity. And a core moving mechanism that moves the core mold toward the inside of the cavity during the injection molding. 2. The injection molding apparatus according to claim 1, wherein the molded product is at least one of an upper body and a lower body of a memory card that accommodates a semiconductor memory therein and is housed in the thin body. The injection molding apparatus is characterized in that the portion to be provided is a portion provided in a recess for accommodating the semiconductor memory of the upper body and the lower body. 3. An injection molding method for producing a molded article having a thin portion using a plurality of mold bodies which can be opened and closed and which form cavities between the mold bodies when the mold is closed. A movable core die that constitutes at least a part of the portion provided for the thin portion, and has an injection step of injecting the molten resin into a cavity, An injection molding method, wherein the core mold is moved toward the inside of the cavity while the resin is injected into the cavity.