KR20150051701A

KR20150051701A - Injection mold for forming product having undercut

Info

Publication number: KR20150051701A
Application number: KR1020130133527A
Authority: KR
Inventors: 이중재; 윤병주
Original assignee: 이중재
Priority date: 2013-11-05
Filing date: 2013-11-05
Publication date: 2015-05-13
Also published as: KR101519949B1

Abstract

The present invention discloses an injection molding die for injection molding a product in which an undercut is distributed in all areas of a product. The disclosed injection molding die comprises an upper mold having an upper core defining an upper side shape of a product formed by injecting a molten resin and an upper mold having an upper circular plate for supporting the upper core, The upper core portion includes a plurality of horizontally movable core pieces which are brought into contact with the lower mold so as to form an undercut in the article so as to be horizontally movable. And a plurality of horizontally moving core pieces are arranged radially with respect to the center of an injection position in which the upper core portion and the lower core portion are aligned in an up-down direction, and when the upper mold and the lower mold are in close contact, So as to define the shape of the upper surface of the article to be inspected.

Description

Technical Field [0001] The present invention relates to an injection mold for forming a product having an undercut,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection mold, and more particularly, to an injection mold for forming a product having an undercut.

Injection molding is a method in which a molten resin is injected into a mold and cooled to form a product. Compared with other molding methods such as compression molding and extrusion molding, And the size is limited, and productivity and workability are excellent, and it is widely used for molding of plastic products.

In the field of injection molding, an undercut is used to mean a stepped or protruded part on the outer or inner side of the product. A typical injection-molded product can take out the injection-molded product by separating the upper and lower core portions which were in close contact with each other after injection and curing of the molten resin. However, a product having an undercut can not be taken out simply by separating the upper and lower core portions which are in close contact with each other, and a core of a more complicated mechanism is required.

In particular, when the undercut is distributed over the entire area of the injection-molded product, a plurality of core pieces corresponding to the undercut shape must be designed to be horizontally moved to interlock with the opening / closing of the mold, it is difficult to construct a compact injection molding die.

Korean Patent Publication No. 10-0817689

The present invention provides an injection molding die for injection molding a product in which an undercut is distributed in all areas of the product.

Further, the present invention provides an injection-molded metal mold having a mold core structure for forming an undercut shape in an upper mold and compactly constituted.

The present invention relates to an upper mold having an upper core portion defining an upper side shape of a finished product formed by injecting a molten resin and an upper mold supporting the upper core portion, And a lower core having a lower core that defines a shape of the upper mold core, wherein the upper core section includes a plurality of horizontal moving cores which are brought into contact with the lower mold so as to form an undercut in the article, Wherein the plurality of horizontally moving core pieces are disposed radially with respect to a center of an injection position in which the upper core portion and the lower core portion are aligned in an up-and-down direction, and when the upper mold and the lower mold are in close contact with each other, Wherein a plurality of horizontally moving core pieces are pinched toward the center of the injection position to define an upper side shape of the article to be injection molded It provides.

The horizontal moving core piece may include an undercut projection on a side of the lower core portion that is in contact with the surface of the lower core portion when the plurality of horizontally moving core pieces are pushed toward the center of the injection position.

The upper core portion includes an upper supporting core piece positioned on the plurality of horizontal moving core pieces, a plurality of connecting rods connecting the upper supporting core piece and the plurality of horizontal moving core pieces, And a plurality of compression springs sandwiched between the upper support core piece and the plurality of horizontally moving core pieces sandwiched between the upper support core piece and the plurality of horizontal movement core pieces, As the upper supporting core piece gets closer to the lower core part, the upper supporting core piece and the plurality of horizontal moving core pieces come closer to each other and the plurality of horizontally moving core pieces are pushed toward the center of the injection position, Wherein the upper supporting core piece and the plurality of horizontal moving pieces And the plurality of horizontally movable core pieces may be configured to expand radially with respect to the center of the injection position.

Wherein the upper core portion includes a plurality of guide rails fixed to the outer periphery of the horizontally moving core pieces and extending obliquely downwardly and a pair of guide rails fixed to the upper circular plate, And may further include a plurality of outer supporting core pieces fixedly supported.

Wherein the upper core portion has a hook which is fixed to a lower side of the horizontally moving core piece and moves in a horizontal direction together with the horizontally moving core piece, and the lower core portion has a plurality of horizontal moving core pieces And a fixing hook, which is fastened to the moving hook to maintain the close contact state of the upper core part and the lower core part.

The upper core portion may include a slide link that connects the adjacent pair of horizontally moving core pieces to guide the adjacent pair of horizontally moving core pieces in an aligned state or in close contact with each other.

Wherein the molten resin is a first molten resin, the upper core portion is a primary upper core portion, the injection position is a primary injection position, the injection product is an intermediate transfer product, the upper mold is supported on the upper original plate, Further comprising a second upper core portion defining an upper side shape of an end product to be molded by injecting a second molten resin different from the primary molten resin at a secondary injection position different from the primary injection position, A rotary mold plate for supporting the lower core portion and rotating so that the lower core portion alternates between the injection position and the secondary injection position and a lower original plate for rotatably supporting the rotary mold plate, .

The number of the first upper core portions and the number of the second upper core portions may be the same as the sum of the first upper core portion and the second upper core portion.

The injection molding die of the present invention is configured such that when the upper mold and the lower mold are separated from each other, the final article is adhered to the second upper core, and the final article is separated from the second upper core An eject pin projecting downwardly may be provided on the upper mold.

The injection mold according to the present invention is characterized in that the upper mold has a mold core structure for forming an undercut distributed over the entire area of the product so that the product having such an undercut can be injection molded, Can be configured compactly, that is, in a small size.

Further, the injection-molding mold according to the embodiment of the present invention can rapidly mold a product formed with an undercut and integrally joined with a resin of different kind or different color, through double injection.

1 is a cross-sectional view illustrating an article molded using an injection molding metal mold according to an embodiment of the present invention.
2 is a perspective view illustrating an injection molding die according to an embodiment of the present invention.
3 is an exploded perspective view showing a state in which the upper mold and the lower mold of FIG. 2 are aligned, wherein the lower side of the upper mold is seen.
FIG. 4 is a perspective view illustrating the primary upper core portion of FIG. 2; FIG.
FIGS. 5 and 6 are sectional views sequentially showing the opening and closing of a mold at a primary injection position when a double injection operation is performed using the injection molding die of FIG. 2. FIG.
FIGS. 7 and 8 are sectional views sequentially showing mold opening and closing at a secondary injection position when the double injection operation is performed using the injection molding die of FIG. 2. FIG.

Hereinafter, an injection molding die according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. The terminology used herein is a term used to properly express the preferred embodiment of the present invention, which may vary depending on the intention of the user or operator or the custom in the field to which the present invention belongs. Therefore, the definitions of these terms should be based on the contents throughout this specification.

FIG. 1 is a cross-sectional view of a product molded using an injection molding metal mold according to an embodiment of the present invention. Referring to FIG. 1, Exhibit 1 is a so-called double yarn product, a member in the form of a lampshade in which the intermediate yarn product 2 and the additional yarn product 3 are integrally formed. The intermediate article (2) and the additional article (3) are made of a different kind of resin material or a different color resin material. As a specific example, the intermediate article 2 is an opaque colored resin and the additional article 3 is formed of a translucent colored resin.

A plurality of through holes 7 are formed in the intermediate transfer article 2 so as to horizontally penetrate the intermediate transfer article 2 over the entire area and the through holes 7 are horizontally moved in the first injection molding process. The undercuts require a core to be formed. The additional article 3 is injected and cemented on the outer surface of the intermediate article 2, closing the through-holes 7 in the secondary injection process.

Gate waste 4 is formed at the upper end of the intermediate product 2 due to the primary injection and runner waste 6 is formed at the lower end of the additional product 3 due to the secondary injection. . The gate waste 4 and the runner waste 6 are removed after the final product 1 is taken out of the injection molding die 10 (see FIG. 2). In addition to the gate waist 4, a bolt fastening portion 5 is also formed at the lower end of the additional article 3. The bolt fastening portion 5 is pushed by the ejection pins 56 and 57 (refer to FIG. 8) so that when the final product 1 is taken out of the injection-molding metal mold 10, .

FIG. 2 is a perspective view illustrating an injection molding die according to an embodiment of the present invention. FIG. 3 is an exploded perspective view illustrating a state in which the upper mold and the lower mold are aligned with each other. And FIG. 4 is a perspective view illustrating the primary upper core portion of FIG. 2. FIG. 2 to 4, an injection molding metal mold 10 according to an embodiment of the present invention includes an upper mold 40 and a lower mold 11. As shown in FIG.

The lower mold 11 includes a rotary mold plate 20 rotated by 180 degrees around the rotation center line RL, a lower circular plate 12 rotatably supporting the rotary mold plate 20, And four lower cores 30 fixed on the upper side of the lower core 20. The four lower core portions 30 are arranged on the corner portions of the square or the rectangle centering on the rotation center line RL and are arranged on the protruding surface defining the lower side surface shape of the intermediate transfer article 2 32). At the top of the projecting surface 32 is formed a gate 34 for uniformly and rapidly injecting the primary molten resin into the primary injection cavity C1 (see FIG. 6).

The first upper core portion 60 is tightly fixed to the lower core portion 30 when the upper mold 40 comes close to the lower mold 11 and the injection impact of the molten resin There is provided a fixing hook 35 which is fastened to the moving hook 76 of the first upper core portion 60 so as to maintain a state in which the first upper and lower core portions 60 and 30 are not separated from each other do. A moving hook guide groove (36) is formed around the fixed hook (35) so that the moving hook (76) slides horizontally. The fixing hook 35 and the moving hook guide groove 36 are arranged radially with respect to the center of the four lower core portion projecting faces 32, respectively. The moving hooks 76 are disposed only on a pair of the first upper core portions 60 and are arranged radially with respect to the center of the primary injection position IC1.

Although not shown, a rotary shaft extends downward along a rotation center line RL on the lower side of the rotary mold plate 20, and a shaft connection hole is formed in the center of the lower circular plate 12 so that the rotary shaft passes through . The lower end of the rotary shaft projecting downward through the lower circular plate 12 is connected to receive the rotational power of the motor so that the rotary mold plate 20 can be repeatedly rotated at intervals of 180 degrees.

The upper mold 40 has an upper mold base 41, an upper circular plate 46, two primary upper core portions 60, and two secondary upper core portions 90. The upper mold base 41 supports the upper circular plate 46 and has a primary molten resin injected from the outside of the injection mold 10 into the primary injection sprocket A sprue bush 42 and a secondary injection sprue bush 44 which is an inlet through which the secondary molten resin is injection-injected from the outside of the injection-molding mold 10 to the inside during the secondary injection.

The upper disk 46 supports the primary upper core portion 60 and the secondary upper core portion 90. The primary upper core portion 60 is provided in the primary injection position IC1 and has the shape of the intermediate yarn introduction 2 (see FIG. 1) molded by injecting the primary molten resin at the primary injection position IC1 . The primary upper core portion 60 includes eight horizontally movable core pieces 65 that are horizontally movable to form an undercut 7 (see FIG. 1) in the intermediate article 2 (see FIG. 1) And an upper supporting core piece 61 (see FIG. 5) which supports the eight horizontal moving core pieces 65 and is fixed to the upper circular plate 46.

The eight horizontal moving core pieces 65 are arranged radially with respect to the center of the primary injection position IC1. When the upper mold 40 is lowered and brought into close contact with the lower mold 11, the eight horizontal moving core pieces 65 are pinched toward the center of the primary injection position IC1, The upper side surface shape of the upper surface of the substrate W is limited. In order to form an undercut 7 (see Fig. 1) in the form of a through hole, on the surface of the horizontally moving core piece 65 which defines the lateral shape on the intermediate blanks 2, A projection 67 is formed. The undercut protrusions 67 are formed in such a manner that when the upper mold 40 and the lower mold 11 come in close contact with each other and the eight horizontal moving core pieces 65 are pinched toward the center of the primary injection position IC1, 30). A further description of the primary upper core portion 60 will be described below with reference to Figs. 5 and 6. Fig.

The secondary upper core portion 90 is molded by injecting the secondary molten resin into the intermediate yarn 2 (see Fig. 1) adhering to the lower core portion projecting face 32 at the secondary injection position IC2 Thereby defining the shape of the upper side of the final product (1). The surface defining the shape of the upper side of the finished article 1 of the secondary upper core portion 90 is a concave surface 92 corresponding to the lower core portion projecting surface 32. A further description of the secondary upper core portion 90 will be described below with reference to FIGS. 7 and 8. FIG.

When the upper mold 40 is lifted and separated from the lower mold 11, the final injection article 1 (see FIG. 1) injection-molded is adhered to the concave surface 92 of the second upper core portion 90 The upper mold 40 includes eject pins 56 and 57 (FIGS. 7 and 8) projecting downward to separate the final product 1 from the concave surface 92 of the second upper core portion 90 8). An ejection pin actuator 50 is mounted on the side surface of the upper mold 40 to allow the upper end portion 51 to move up and down. The upper end portion 51 of the ejection pin actuator 50 includes a horizontal extension block 52 extending into the upper mold 40 And is fastened to the one side end portion. The other end of the horizontal extension block 52 is fastened to an eject pin support plate 54 (see FIGS. 7 and 8) disposed in a space above the secondary upper core portion 90. The eject pins 56 and 57 are supported by the eject pin support plate 54 and extend down through the secondary lower core portion 90. The eject pin actuator 51 can lower the upper end portion 51 and project the end of the ejection pins 56 and 57 below the concave surface 92 of the secondary upper core portion 90 1 can be separated from the concave surface 92 of the secondary upper core portion 90.

The injection molding die 10 is an upper mold aligning means for aligning the upper mold 40 so as to be brought into close contact with the lower mold 11 accurately and includes alignment protrusions 48, an auxiliary alignment protrusion 49, do. The aligning protrusions 48 are provided on the pair of side surfaces of the four sides of the upper mold 40 and are installed to protrude toward the lower mold 11. [ The auxiliary aligning protrusions 49 are provided on the side faces of the remaining one of the four side faces of the upper mold 40 and are installed to protrude toward the lower mold 11. [

The alignment protrusion receiving portion is formed so that a pair of alignment protrusions 48 can be received in the lower mold 11. [ Specifically, the alignment projection accommodating portion includes a lower disk alignment groove 13 formed in the lower disk 12 so as to be aligned with the alignment projection 48, and a lower disk alignment groove 13 formed in the lower core 12 so that the lower core portion 30 is aligned with the primary projection position IC1 or And a rotary mold plate alignment groove 25 formed in the rotary mold plate 20 so as to be aligned with the alignment protrusion 48 and the lower disc alignment groove 13 only when aligned with the secondary injection position IC2 . On the other hand, only when the lower core portion 30 is aligned with the primary injection position IC1 or the secondary injection position IC2, the rotary mold plate 20 is provided with a pair of auxiliary alignment projections 49 A pair of rotating mold plate alignment grooves 25 to be aligned are further provided.

When the upper mold 40 descends and approaches the lower mold 11, a pair of alignment protrusions 48 are fitted in the rotating mold plate alignment groove 25 and the lower disc alignment groove 13 aligned in a row, The upper mold 40 is brought into close contact with the lower mold 11 in an accurately aligned state when a pair of auxiliary alignment projections 49 are fitted and fitted in the remaining rotating mold plate alignment grooves 25. [ The alignment protrusions 48 and the auxiliary alignment protrusions 49 are not seated on the lower mold 11 unless the upper mold 40 is accurately aligned with respect to the lower mold 11. Therefore, 11 without being brought into close contact with each other. Accordingly, problems such as damage to the injection-molded metal mold 10 or generation of defective products caused by the close contact between the upper mold 40 and the lower mold 11 can be prevented in advance.

FIGS. 5 and 6 are sectional views sequentially showing the opening and closing of the mold at the primary injection position when the double injection operation is performed using the injection molding die of FIG. 2. FIGS. 7 and 8 are views showing the injection molding die of FIG. Sectional view sequentially showing the opening and closing of the mold at the secondary injection position when the double injection operation is carried out using the injection molding machine. Hereinafter, the process of forming the final molded article 1 (see FIG. 1) using the injection-molding metal mold 10 (see FIGS. 2 and 4) will be sequentially described with reference to FIGS.

Referring to Figure 5, eight horizontal moving core pieces 65 are connected to the upper support core piece 61 by connection rods 70 extending downwardly sloping away from the centerline of the primary injection position IC1, respectively And a compression spring 72 are fitted in the connecting rod 70 and interposed between the upper supporting core piece 61 and the horizontal moving core piece 65, respectively. When the upper mold 40 is separated from the lower mold 11, the compression spring 72 is expanded so that the eight horizontal moving core pieces 65 are spaced apart from the upper supporting core pieces 61, (65).

The injection molding die 10 is configured such that as the upper supporting core piece 61 is brought closer to the lower core portion 30 when the eight horizontal moving core pieces 65 are brought into contact with the lower core portion 30, The eight horizontal moving core pieces 65 are brought close to the center of the primary injection position IC1 while the eight horizontal moving core pieces 65 are moved toward the center of the primary injection position IC1, The upper supporting core piece 61 and the eight horizontal moving core pieces 65 move away from the lower core portion 30 and the eight horizontal moving core pieces 65 move toward the center of the primary injection position IC1 As shown in FIG.

On the outer periphery of the eight horizontal moving core pieces 65, a guide rail 74 extending downward in the same direction as the connecting rod 70 is fixedly mounted. Each guide rail 74 is slidably engaged in the same direction as the extending direction of the guide rail 74 with respect to the outer supporting core piece 63 fixed to the upper original plate 46. The guide rails 74 guide the outer supporting core piece 63 and the upper original plate 46 to slides down or up without being caught by the horizontally moving core pieces 65 when the upper mold 40 is lowered or raised. do.

An adjacent pair of horizontally mobile core pieces 65 are connected to each other by a slide link 78 (see FIG. 4). Specifically, one horizontal moving core piece 65 is fixedly fastened with a slide link 78 extending toward another adjacent horizontal moving core piece 65, and the other horizontal moving core piece 65 is fixed A slide link guide groove 79 for guiding the path of the slide link 78 is formed. The slide link 78 slides along the slide link guide groove 79 when the upper mold 40 is lowered or raised so that the adjacent horizontally movable core pieces 65 can be closely contacted or separated in an aligned state do.

The primary upper core portion 60 is secured to the underside of eight horizontal moving core pieces 65 and has eight moving hooks 76 that move horizontally with each horizontally moving core piece 65. When the upper mold 40 descends toward the lower mold 11, the lower ends of the eight horizontally moving core pieces 65 are first brought into contact with the lower core portion 30 and the moving hooks 76 are moved to the moving hook guide grooves 36 (See Fig. 3). When the upper mold 40 is continuously lowered, the compression spring 72 is compressed so that the upper supporting core piece 61 comes close to the eight horizontally moving core pieces 65, and the connecting rod 70 is connected to the upper supporting core piece 61 ). As a result, the eight horizontal moving core pieces 65 that are in contact with the lower core portion 30 are horizontally moved toward the centerline of the primary injection position IC1.

6, when the upper mold 40 is continuously lowered and the upper supporting core piece 61 is brought into close contact with the eight horizontal moving core pieces 65, the eight horizontal moving core pieces 65 are completely brought into close contact with each other So that the primary injection cavity C1 is defined. At this time, the undercut projection 67 is in close contact with the lower core portion projecting surface 32. On the other hand, as the eight horizontal moving core pieces 65 are pinched and horizontally moved toward the centerline of the primary injection position IC1, the moving hooks 76 move along the moving hook guide grooves 36, 35).

In this state, when the primary injection molten resin is injected into the mold 10 through the primary injection sprue bush 42 (see FIG. 2), a primary injection runner (runner) (80), the primary molten injection resin flows into the gate (34) and diffuses into the primary injection cavity (C1). The primary injection cavity C1 is not opened in spite of the impact when the molten resin is injected and the upper primary core portion 60 and the lower portion The core portion 30 remains in a close contact state.

1) is formed when the primary injection molten resin filled in the primary injection cavity C1 is cured. When the upper mold 40 is lifted, the middle injection part 2 The article (2) is stuck. When the upper mold 40 rises, the compression spring 72 is resiliently restored so that the eight horizontally movable core pieces 65 are spaced apart from each other, and are also separated from the upper support core piece 61. Also, the movable hook 76 is separated from the fixed hook 35 so that the upper mold 40 is not interrupted.

The rotary mold plate 20 (see Fig. 2) is rotated by 180 degrees with the upper mold 40 and the lower mold 11 being spaced apart from each other so that the intermediate transfer article 2 (See FIG. 1) is taken out at the secondary injection position IC2, and the two lower core portions 30 are moved to the secondary injection position IC2 at the secondary injection position IC2 The two lower core portions 30 move to the primary injection position IC1.

7, when the upper mold 40 is lowered again toward the lower mold 11, the secondary upper core portion 90 is brought into close contact with the lower core portion 30 at the secondary injection position IC2, The injection cavity C2 is defined. In the secondary injection cavity C2, an intermediate article 2 adhered to the lower core portion projecting surface 32 is disposed. When the secondary injection molten resin is injected into the mold 10 through the secondary injection sprue bush 44 (refer to FIG. 2) in this state, the secondary injection molten resin is injected into the mold 10 through the secondary injection runner the secondary injection molten resin is injected into the secondary injection cavity C2 through the runner 95 to be diffused. The molten resin injected into the secondary injection cavity C2 also flows into the undercut 7 in the form of a through hole of the intermediate product 2 to close the through hole.

When the secondary injection molten resin filled in the secondary injection cavity C2 is cured, an end product 1 (see Fig. 1) in which the additional article 3 and the intermediate article 2 are integrally joined is formed. The runner waste 6 formed by curing the molten resin left in the runner 95 and the bolt fastening portion 5 protruding upward can prevent the surface area of the lower core portion projecting surface 32 from becoming larger than the surface area of the lower core portion projecting surface 32, The surface area of the concave surface 92 of the concave surface 92 of the upper mold 40 is larger than that of the concave surface 92 of the concave surface 92 when the upper mold 40 is raised again.

8, when the upper end 51 of the eject pin actuator 50 is lowered in a state in which the upper mold 40 is raised, the horizontal extension block 52, the eject pin support plate 54, The pins 56 and 57 descend and the lower ends of the eject pins 56 and 57 protrude below the concave surface 92 so that the finished article 1 is pressed against the concave surface 92 of the second upper core portion 90, Lt; / RTI > One of the eject pins 56 and 57 pushes the upper end of the bolt fastening part 5 down and the other one pushes the surface of the final product 1 next to the bolt fastening part 5 downward It pushes. The worker can take out the final product 1 separated from the concave surface 92 and the rotary mold plate 20 (see Fig. 2) can be rotated 180 degrees again to return to the original position.

2 and 3, the injection molding die 10 is provided with a constitution for forming an undercut in the first upper core portion 60 to form an undercut 7 (see FIG. 1) on the intermediate article 2 (See FIG. 1), but the present invention is not limited thereto. For example, a configuration for forming an undercut may be provided in the second upper core portion so that an undercut can be formed on the outer surface of the final product.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the scope of the present invention. Therefore, the true scope of protection of the present invention should be defined only by the appended claims.

1: Final product 2: Intermediate product
10: injection molding die 11: lower mold
12: lower original plate 13: lower original plate aligned groove
20: rotary die plate 30: lower core part
35: Fixing hook 40: Upper mold
60: primary upper core portion 65: horizontal moving core piece
67: undercut projection 74: guide rail
76: Moving hook 90: Secondary upper core part

Claims

An upper mold having an upper core portion defining an upper side shape of the article to be formed by injecting a molten resin and an upper disk supporting the upper core portion; And a lower core having a lower core for defining a shape of a bottom surface of the article to be inspected,
The upper core portion includes a plurality of horizontally moving core pieces that are horizontally movable in contact with the lower mold so that an undercut is formed in the finished product,
Wherein the plurality of horizontally moving core pieces are arranged radially with respect to a center of an injection position in which the upper core portion and the lower core portion are aligned up and down,
Wherein when the upper mold and the lower mold are in close contact with each other, the plurality of horizontally moving core pieces are pinched toward the center of the injection position to define an upper surface shape of the article.

The method according to claim 1,
And the horizontal moving core piece has an undercut projection on a side of the lower core portion that is in contact with the surface of the lower core portion when the plurality of horizontally moving core pieces are pinched toward the center of the injection position, Injection molding mold.

The method according to claim 1,
Wherein the upper core portion comprises: an upper supporting core piece positioned above the plurality of horizontally moving core pieces; A plurality of connecting rods connecting the upper supporting core piece and the plurality of horizontal moving core pieces; And a plurality of compression springs sandwiched between the connection rods and interposed between the upper supporting core piece and the plurality of horizontal moving core pieces,
The upper supporting core piece and the plurality of horizontal moving core pieces are closer to each other as the upper supporting core piece is brought closer to the lower core part when the plurality of horizontally moving core pieces contact the lower core part, The horizontally moving core piece is pushed toward the center of the injection position, and conversely, as the upper supporting core piece is further away from the lower core portion, the upper supporting core piece and the plurality of horizontal moving core pieces are separated from each other, Wherein the horizontally moving core piece is configured to expand radially with respect to the center of the injection position.

The method of claim 3,
The upper core portion includes a plurality of guide rails fixed to the outer periphery of the horizontally moving core pieces and extending obliquely downward; And
Further comprising: a plurality of outer support core pieces fastened to the guide rails so as to be slidable and fixed to the upper original plate.

The method according to claim 1,
Wherein the upper core part is fixed to a lower side of the horizontally moving core piece and has a moving hook moving horizontally with the horizontally moving core piece,
Wherein the lower core portion includes a fixing hook which is fastened to the moving hook when the plurality of horizontally moving core pieces are clasped to maintain the close contact state of the upper core portion and the lower core portion. .

The method according to claim 1,
Wherein the upper core portion includes a slide link that connects adjacent pair of horizontally moving core pieces to guide the adjacent pair of horizontally moving core pieces in an aligned state in close contact or spaced apart. mold.

The method according to claim 1,
Wherein the molten resin is a first molten resin, the upper core portion is a first upper core burr, the injection position is a primary injection position, the injection product is an intermediate transfer article,
The upper mold is supported on the upper circular plate and defines an upper surface shape of an end product to be molded by injecting a secondary molten resin different from the primary molten resin at a secondary injection position different from the primary injection position Further comprising a second upper core portion,
Wherein the lower mold includes: a rotary mold plate supporting the lower core portion and rotating so that the lower core portion alternates between the injection position and the secondary injection position; And
And a lower circular plate rotatably supporting the rotary mold plate.

8. The method of claim 7,
Wherein the first upper core portion and the second upper core portion are provided in a plurality of the same number,
Wherein the lower core portion has the same number as the sum of the first upper core portion and the second upper core portion.

8. The method of claim 7,
Wherein when the upper mold and the lower mold are separated from each other, the final product is adhered to the second upper core portion,
Wherein the upper mold has an eject pin projected downward to separate the final product from the secondary upper core.