JP2000084982A - Injection mold and injection molding method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection mold capable of producing a disc-shaped thick-walled part with high dimensional precision by using a fiber reinforced grade resin or the like and an injection molding method using the same. SOLUTION: In an injection mold, a movable mold 5 forming a cavity 10 in opposed relation to a fixed mold 1 is divided into the outer cylindrical molds 51a, 51b having round holes provided in the centers thereof and fixed to a movable plate 6 and the compression mold 52 inserted into the center round holes of the outer cylindrical molds 51a, 51b in a freely advancing and retreating state and a compression mold driving apparatus capable of allowing the compression mold 52 to advance and retreat in the advance and retreat direction of the movable mold are provided. In an injection molding method, this injection mold is used to drive the compresion mold 52 so as to allow the same to advance and retreat in predetermined timing at the time of molding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding die and an injection molding method using the same, and more particularly to an injection molding die suitable for manufacturing a disk-shaped seal member and an injection molding method using the same.

[0002]

2. Description of the Related Art FIG.
As shown at 00, the pressure and flow rate of the medium are controlled by meshing with the metal valve seat 101, and the meshing portion 100a with the metal valve seat 101 is formed in a conical shape. As a material of such a disc-shaped seal member, a fiber reinforced grade resin of super engineering plastic such as polyimide resin, PEEK, PES, or PPS is used.

Conventionally, such a disk-shaped sealing member is formed from a fiber-reinforced grade resin by a general injection molding method using a mold having no cavity compression member. (Circularity) and the flatness of the bottom surface portion 100b are poor, and finally these parts are cut and secondary processed to achieve a predetermined accuracy, thereby increasing the number of steps and increasing the cost. There are drawbacks.

That is, in the injection molding of a disk-shaped thick molded product such as a disk-shaped sealing member, when the resin is filled into the cavity, the resin is filled while expanding concentrically, thereby increasing roundness. Necessary to achieve. However,
When such a thick molded product is molded by a normal injection molding die, when the resin is injected from the gate into the cavity, the unstable flow in which the resin flows without touching the inner surface of the die in the enlarged channel portion, so-called The jetting phenomenon occurs. As a result, the resin does not flow concentrically, and the fibers in the resin do not orderly and radially (radially) from the center, so that anisotropy of the shrinkage rate occurs upon solidification, and the engagement portion Roundness and the flatness of the bottom portion are greatly reduced. Further, in general injection molding, pressure transmission into the cavity is performed by flowing molten resin from the gate portion into the cavity. However, in this method, pressure transmission in the slope portion is insufficient, and the surface of the mold is insufficient. Transfer to a resin molded product becomes poor, and the roundness of the slope cannot be achieved.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to use a fiber-reinforced grade resin or the like to form a conical member such as a disk-shaped seal member. An object of the present invention is to provide an injection molding die for molding a disk-shaped thick part having a surface or the like and requiring high dimensional accuracy, and an injection molding method using the same.

[0006]

In order to achieve the above object, an injection mold according to the present invention comprises a movable mold having a cavity formed opposite a fixed mold and having a circular hole formed at the center thereof. Having an outer cylinder type fixed to the movable platen and a compression type which is inserted and retractably inserted into a center circular hole of the outer cylinder type,
It is characterized in that a compression type driving device capable of moving the compression type in the moving direction of the movable plate is provided. In addition, the injection molding method according to the present invention uses the above-described injection mold to perform the following steps (a) to (e), that is, (a) the movable mold toward the fixed mold. (B) moving the whole to close the mold, (b) advancing the tip of the compression mold into the cavity, narrowing the resin flow path in the cavity, and reducing the cavity volume from the original volume; c) while injecting the resin into the cavity, gradually retracting the compression mold by the injection pressure and injecting the resin until the cavity volume becomes larger than the original volume; and (d) after the resin injection is completed, the compression mold (E) compressing the resin to the original cavity volume while gradually increasing the resin pressure toward the cavity while increasing the resin pressure in the cavity.
Cooling and solidifying the resin in the cavity by a conventional method, and then opening the mold and taking out a molded product.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings. FIG. 1 is a cross-sectional view showing an essential part of an embodiment of an injection mold according to the present invention. FIGS. 2 to 4 are explanatory diagrams showing steps of performing injection molding using the mold. FIG. 5 is an explanatory view of a disc-shaped sealing member that can be suitably molded according to the present invention.

In the drawing, 1 is a fixed mold, 2 is a sprue bush, 3 is a fixed platen, 4 is a locator ring, 5
Is a movable side mold composed of outer cylinder molds 51a and 51b and a compression mold 52, 6 is a movable plate, 7 is a compression type driving device (see FIG. 2),
8 is an ejector pin, 9 is a fixed mold 1 and a movable mold 5
And 10 are cavities, and 11 is a resin (see FIG. 2) filled in the cavities. As shown in FIG. 2, for example, a compression-type driving device 7 includes a base 71 that is driven vertically in the drawing,
It is constituted by a rod 72 connecting the base and the compression mold 52.

As shown in the figure, in the mold according to the present invention, the movable mold 5 is fixed to a movable plate 6 and has outer cylinders 51a and 51b having a circular hole at the center thereof. And a compression-type driving device 7 capable of moving the compression die 52 forward and backward in the moving direction of the movable plate. I have. By using this mold and moving the tip of the compression mold 52 into and out of the cavity 10 when filling the resin, the cavity volume, the flow path can be expanded or reduced, and the resin can be compressed. It is possible to form a disk-shaped thick part with high accuracy by using the method described above.

That is, when a disk-shaped sealing member is formed by using this mold, as shown in FIG. 2, the compression mold 52 is first advanced toward the cavity so that the resin 11 is injected from the gate. Cavity thickness (resin flow path)
Is reduced from about 5% to about 70% of the dimension of the molded product. If the cavity thickness is narrowed in this manner, unstable flow due to a sudden expansion of the flow path when the resin is injected from the gate into the cavity is prevented. FIG. 2 shows a state in which the distal end of the compression mold 52 protrudes into the cavity by a step p = 2.5 mm from the position where the original cavity volume is formed as shown in FIG. 1 or FIG. ing.

Then, as shown in FIG. 3, the compression mold 52 is retracted from the cavity by the injection pressure of the resin 11, thereby gradually increasing the cavity volume in accordance with the injection amount of the resin. By the above operation, unstable flow and jetting of the resin in the resin injection process can be prevented, so that the resin is filled while being concentrically spread in the thick portion, and uneven orientation of the fiber can be suppressed. . While the resin is being injected, the compression mold 52 is further retracted, and the resin is injected by 1 to 20% more than the desired volume of the molded product to secure a compression margin. In FIG. 3, the tip of the compression mold 52 is
A state is shown in which the step is retracted by a step q = 2 mm from the position where the original cavity volume is formed as shown in FIG. 1 or FIG.

Next, as shown in FIG. 4, the compression mold 52 is advanced and the resin 11 in the cavity is compressed to bring it to the original cavity volume position. To improve
A molded product with high dimensional accuracy can be obtained.

The size of a molded product that can be suitably produced according to the present invention is 20 to 200 mm in outer diameter, preferably 20 to 150 mm.
mm. The thickness is about 5 to 30 mm. Further, as the resin material that can be suitably used in the present invention, polyimide,
Polyether ether ketone, polyether sulfone, polyphenylene sulfide and the like can be mentioned. Also,
These super-engineering plastics or their fiber (glass fiber, carbon fiber) reinforced grades are also preferably used. Preferred molding conditions are temperature 3
00 to 430 ° C., dwell pressure (resin pressure in the operation state shown in FIG. 2) 5 to 100 MPa, and compression pressure (resin pressure during the compression operation in FIG. 4) 10 to 80% higher than the dwell pressure described above. It is desirable.

[0014]

EXAMPLE A disk-shaped sealing member having the shape shown in FIG. 5 was produced under the following conditions by the above-described operation using the injection mold according to the present invention. Material resin: Thermoplastic polyimide fiber reinforced grade (trade name: Aurum JCN6230, manufactured by Mitsui Chemicals) Molding machine resin temperature: 420 ° C Mold temperature: 200 ° C Holding pressure: 160 MPa for 10 seconds Compression pressure: 230 MPa for 40 seconds Injection speed: 3 mm / s Engaging part 1 of disc-shaped sealing member obtained by this
00a (see FIG. 5) has a roundness of 25 μm and a bottom surface 100b
Had a flatness of 20 μm, and required accuracy was obtained without requiring secondary cutting. On the other hand, when a similar disk-shaped seal member was manufactured by a conventional method using a conventional injection molding die, the roundness of the engaging portion was 70%.
μm and the flatness of the bottom surface was 80 μm, and secondary cutting was required to achieve the accuracy required for the disc-shaped seal member.

[0015]

According to the present invention, since the present invention is constituted as described above, 1) the roundness and flatness of a molded article are greatly improved, and 2) the secondary processing can be eliminated. Was.

[Brief description of the drawings]

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

FIG. 2 is an explanatory view showing a first stage when performing injection molding using the mold shown in FIG. 1;

FIG. 3 is an explanatory diagram showing a second stage.

FIG. 4 is an explanatory diagram showing a third stage.

FIG. 5 is an explanatory view of a disc-shaped seal member that can be suitably molded according to the present invention.

[Explanation of symbols]

 1) Fixed side mold 2) Sprue bush 3) Fixed side platen 4) Locator ring 5) Movable side mold 51a, 51b {outer cylinder type 52} ─Compression type 6────Movable platen 7────Compression type driving device 8────Ejector pin 9────Parting line 10───Cavity 11───Resin

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hideto Ogasawara 2-1-1 Tango-dori, Minami-ku, Nagoya-shi, Aichi F-term (reference) in Mitsui Chemicals, Inc. 4F202 AA40 AB25 AG19 CA11 CK07 CK18 CK19 CK42 CK73 CL11 4F206 AA40 AB25 AG19 JA07 JM02 JM04 JN33 JQ81 JT05

Claims (2)

[Claims] A movable mold (5) forming a cavity (10) facing a fixed mold (1), and an outer cylinder having a circular hole at the center and fixed to a movable plate (6). Type (51a, 51
b) and a compression mold (52) that is inserted into the center hole of the outer cylinder so as to be able to advance and retreat.
2. A mold for injection molding, wherein a compression-type driving device (7) capable of moving the movable plate in the moving direction of the movable plate is provided. 2. An injection molding method using the injection molding die according to claim 1, wherein the following steps (a) to (e) are sequentially performed. (a) A step of moving the entire movable mold (5) toward the fixed mold and closing the mold. (b) a step of causing the tip of the compression mold (52) to advance into the cavity (10), narrowing the resin flow path in the cavity, and reducing the cavity volume from the original volume. (c) a step of gradually retracting the compression mold (52) by the injection pressure while injecting the resin (11) into the cavity, and injecting the resin until the cavity volume becomes larger than the original volume. (d) After the resin injection is completed, a step of gradually compressing the resin into the cavity by gradually moving the compression mold (52) toward the cavity and compressing the resin until the cavity volume reaches the original volume. (e) After the resin in the cavity is cooled and solidified by a conventional method, a step of opening the mold and taking out the molded product.