KR20160039420A

KR20160039420A - Injecction mold with unit for dealing with undercut

Info

Publication number: KR20160039420A
Application number: KR1020140132444A
Authority: KR
Inventors: 이민한
Original assignee: 대일엠티에스 주식회사
Priority date: 2014-10-01
Filing date: 2014-10-01
Publication date: 2016-04-11

Abstract

Disclosed is an injection mold with an undercut processing unit which limits the shape of undercut of an injection molded article, and separated from the undercut part of the injection molded article after being opened for the injection molded article to be taken out from the mold. The disclosed undercut processing unit of the injection mold comprises a protruding block coming in contact with a first core by being inserted into a concave groove of a second core, having the side surface with a guide groove which is tilted to be narrower from the upper surface coming in contact with the first core to the lower surface coming in contact with the second core, and protruding toward the first core; and a slider located in the concave groove, supported by the second core to limit the shape of the undercut and to be slid to the guide groove of the protruding block, and formed to be detached from the undercut by protrusion of the protruding block.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an injection mold having an undercut processing unit,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an injection molding die, and more particularly, to an injection molding die that limits the shape of an undercut of an injection molding in a die, And an injection molding die having a processing unit.

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. When an injection-molded product is molded using an injection-molding mold, the molten resin is injected into a cavity in the mold through a sprue, a runner, and a gate to be hardened, the eject plate is raised and the eject pin is pushed up, and the ejected material is separated from the mold and taken out from the mold.

A portion of the injection mold that is difficult to separate from the mold in the process of taking out the injection molded product is a part that protrudes in the direction intersecting the moving direction of the upper mold or the lower mold at the time of mold opening, undercut). Korean Patent Registration No. 10-0846850 and Korean Registered Utility Model No. 20-0444791 disclose a structure in which the shape of the undercut is limited and the take-out is not disturbed due to undercut at the time of mold opening , A deformed milfin that extends upward obliquely is disclosed. The modified milfin is particularly applied as a structure for forming and extracting an undercut formed on the inner peripheral surface of an injection molded article, that is, an inner undercut.

However, such an inclined deformed miliphin structure concentrates the long impact of the molten resin when the molten resin is injected into the elongated long molten fin, accumulating the fatigue of the molten fin and increasing the risk of breakage. Furthermore, when a plurality of inner undercuts are provided in the molded article, the structure inside the lower mold including the inclined milf is complicated, which makes it difficult to assemble and disassemble the injection-molded mold, and the operation time is delayed.

Korean Patent Registration No. 10-0846850 Korean Utility Model Registration No. 20-0444791

The present invention provides an injection molding die having an undercut processing unit which defines the shape of an undercut of an injection molding and which is separated from the undercut portion of the injection molding after the mold opening so that the injection molding can be taken out of the mold.

The present invention also provides an injection molding die having an undercut processing unit that is not associated with a milfin which is pushed up by a plate, and which does not have an inclined milfin.

In addition, the present invention according to a preferred embodiment provides an injection-molding mold having an undercut processing unit for injection-molding an injection molded article having a plurality of inner undercuts and an opening formed therein.

According to the present invention, there is provided an injection molding die for molding an injection molding having a hollow center shape and an undercut on a side, comprising: a first core having a first defining surface defining a side surface shape of the injection molding; A second core having a second defining surface defining an opposite side surface shape of the undercut, the second core having a recessed groove in the middle, and a second core defining a shape of the undercut, wherein when the first core and the second core are spaced apart from each other, And an undercut processing unit which is spaced apart from the undercut so as to be able to take out from the injection molding die, wherein the undercut processing unit is inserted into a concave groove of the second core and is in contact with the first core, And a side surface having a guide groove inclined so that a width from an upper surface in contact with the core to a lower surface in contact with the second core is gradually narrowed, And a second protruding block which is located in the recessed groove and which is supported on the second core so as to define a shape of the undercut and to be slidable in a guide groove of the protruding block, And a slider formed so as to fall out of the mold.

The protruding block is elastically biased in a direction protruding toward the first core and the slider has an undercut defining groove defining a shape of the undercut, And a second position in which the undercut defining groove is spaced apart from the second limiting surface.

The injection mold according to the present invention is characterized in that, when the first core and the second core are brought into close contact with each other, the projecting block is pushed by the first core to move in the direction of insertion into the recessed groove, When the first core and the second core are separated from each other, the protruding block moves in a direction in which the protruding block protrudes from the concave groove, and the slider is pulled by the protruding block, Position of the < / RTI >

A plurality of the undercut defining grooves may be formed in the slider, and the shapes of the plurality of undercut defining grooves may be the same or different.

Wherein the undercut processing unit includes a spring inserted into a spring insertion groove provided in the second core and elastically supporting the protruding block, and a spring extending through the spring, wherein one side is fixed to the second core, Side may further include a spring support pin which is slidably fitted to the protruding block.

The undercut processing unit may further include a guide pin slidably fitted on one side of the second core and the other side fixed to the projecting block, A stopper may be provided to restrict a protruding range of the protruding block by limiting the range of movement of the protruding block.

The undercut processing unit may further include a damper interposed between the protruding block and the second core, the damper being composed of an elastic body for absorbing an impact when the protruding block collides with the second core.

The plurality of sliders may be provided, and the plurality of sliders may be fastened to the protruding blocks.

According to the present invention, an injection molded article having an undercut can be formed and taken out without having an inclined deformed mold, so that it is not necessary to repair the injection molded mold due to fatigue accumulation and breakage of the mold. Therefore, it is possible to reduce the direct costs of repairing the injection molding die and the indirect costs due to the production disruption.

In addition, since the inclined deforming pin is not provided, the structure of the mold becomes simple, which facilitates assembly and disassembly and reduces the working time. Further, since the clearance for forming the refrigerant passage is enlarged in the core of the injection-molding metal mold, the refrigerant passage can be sufficiently formed to rapidly cure the resin. Therefore, the productivity of the injection molding is improved.

1 is an exploded perspective view showing an upper core, a lower core, and a lift block of an injection molding die according to an embodiment of the present invention.
FIG. 2 is a plan view showing a state where the lower core and the lift block of FIG. 1 are coupled.
3 is an exploded perspective view showing the elevating block and the slider of FIG.
Fig. 4 is a cross-sectional view cut along the line AA of Fig.
Figs. 5 and 6 are sectional views sequentially showing the operation of the protruding block and the slider, and are views showing the cutaway of Fig. 2 along BB. Fig.
FIG. 7 is a perspective view showing an injection molding formed using the injection molding die of FIG. 1. FIG.

Hereinafter, an injection molding die having an undercut processing unit 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 of 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 an exploded perspective view showing an upper core, a lower core, and a lift block of an injection molding die according to an embodiment of the present invention, FIG. 2 is a plan view showing a state where the lower core and the lift block of FIG. FIG. 3 is an exploded perspective view showing the lift block and the slider of FIG. 1, and FIG. 4 is a cross-sectional view cut along the line AA in FIG. 2, It is a perspective. Referring to FIGS. 1 to 4 and FIG. 7 together, the injection-molding die according to the embodiment of the present invention is for molding an injection molded article 1 having a plurality of undercuts 3, A second core 20, and an undercut processing unit 30. The plurality of undercuts 3 are so-called inner undercuts formed in the vicinity of the inner circumference of the molded article 1. The openings 4 are formed in the center of the molded article 1,

The first core 13 may be provided in a fixed side mold (not shown) in which a flow path for injecting a molten resin into the mold, such as a sprue, a runner, or a gate, is formed. The first core 13 has a first limiting surface (not shown) which defines one side surface shape of the molded article 1. The second core 20 is provided in a movable side mold (not shown) movable in parallel with the positive side mold or in the direction of moving away from the stationary side mold, that is, in the positive Z direction positive or negative direction . The second core (20) has a second defining surface (24) defining an opposite lateral shape of the molded article (1).

When the fixed side mold and the movable side mold come into close contact with each other, the first limiting surface, the second defining surface 24, and the undercut defining groove 36 and the undercut peripheral defining surface 35 of the slider 31, Thereby forming a cavity defining the complete shape of the injection molding. The molten resin is injected into the cavity and cured to mold the molded article 1.

Although not shown in the figure, the movable mold may include an eject plate and an eject pin for separating and extracting the injection object 1 formed in the cavity from the second confinement surface 24. The milfin is a so-called simple milfin extending parallel to the Z axis and not a so-called modified milfin extending obliquely to the Z axis.

The undercut processing unit 30 defines the shape of the undercut 3 and can take out the mold 1 from the injection mold 10 when the first core 13 and the second core 20 are separated from each other So as to be spaced apart from the outer cutter (3). The undercut processing unit 30 includes a protruding block 50 and a plurality of sliders 31. The protruding block 50 is inserted into the concave groove 26 provided at the center of the second core 20 and is inserted in the direction projecting toward the first core 13, As shown in FIG.

Since the opening 4 is formed in the center of the molded article 1 as described above, the first limiting surface (not shown) is formed at the center of the first core 13 and the second core 20, And the second limiting surface 24 are not disposed. In addition, the protruding block 50 is configured to be contact-urged by the first core 13. Therefore, the protruding block 50 is arranged to be inserted and mounted at the center point of the second core 20 corresponding to the central opening 4 of the injection product 1. [

The injection molding die 10 is a means for resiliently biasing the projecting block 50 in parallel with the Z axis positive direction and includes a pair of springs 42 and a pair of spring support pins 40 ). Each of the pair of springs 42 is inserted into the spring insertion groove 27 which is dug into the concave groove 26 of the second core 20 to elastically support the projecting block 50. The protruding block 50 may be formed with a spring receiving groove 58 that is formed in a stepped manner so that the end of the spring 42 is seated at a position corresponding to the spring insertion groove 27. A pair of spring support pins 40 extend through the spring 42 and extend parallel to the Z axis and one side is fixed to the second core 20 and the other side is fixed to the Z axis And is fitted in a spring supporting pin hole 55 formed in the protruding block 50 so as to be able to slide in a direction parallel to the direction of the axis.

The injection molding die 10 is a means for preventing the protruding block 50 from being separated from the second core 20 by limiting the range in which the protruding block 50 protrudes in the positive Z- A pair of guide pins 45, and a pair of stoppers 29a. The pair of guide pins 45 extend respectively in parallel with the Z axis and one side is slidably fitted in parallel with the Z axis with respect to the second core 20 and the other side is fitted with a guide formed in the protruding block 50 Is fitted into a pin hole (56) and is fixedly fastened to the protruding block (50). A flange 46 is formed at one end of each guide pin 45 so as to have a stepped diameter. A second core 20 has an inner diameter corresponding to the diameter of the flange 46 and is parallel to the Z axis The flange insertion groove 29 is formed. The flange 46 is reciprocable within the flange insertion groove 29 in parallel with the Z-axis.

When the flange 46 moves in parallel with the positive Z-axis direction and touches the end point 29a of the flange insertion groove 29, the movement of the flange 46 is blocked, And the end point 29a becomes a stopper. The protruding block 50 can protrude from the second core 20 until the flange 46 is blocked by the stopper 29a unless the protruding block 50 is pressed by the first core 13, And can be inserted into the concave groove 26 until the bottom surface 51b comes into contact with the bottom of the concave groove 26.

The injection molding die 10 includes a pair of dampers interposed between the protruding block 50 and the second core 20 to cushion impacts of the protruding block 50 and the second core 20 in collision, (48). The damper 48 may be formed of an elastic material such as urethane or rubber and may have a thickness of about 2 to 3 mm at the bottom surface of the concave groove 26 when the protruding block 50 is separated from the second core 20. [ And is fixed to the second core 20 so as to protrude.

Each of the plurality of sliders 31 includes an undercut limiting groove 36 defining an undercut 3 shape of the molded article 1 and an undercut peripheral defining surface 35 defining a shape around the undercut 3 . Each slider 31 has a first position (see FIG. 5) where the undercut limiting groove 36 and the undercut peripheral limit surface 35 are connected to the second limiting surface 24 of the second core 20, The undercut limiting groove 36 and the undercut peripheral limiting surface 35 are fastened to the second core 20 so as to reciprocate between a second position (see FIG. 6) in which the undercut limiting groove 36 is spaced from the second limiting surface 24, Is fastened to the protruding block (50) so as to be slidable in an inclined direction with respect to the protruding block (50).

Specifically, each slider 31 has a horizontal guide rail 34 extending parallel to the Y-axis direction and protruding therefrom. The horizontal guide rail 34 is fitted in a horizontal guide groove (not shown) provided in the second core 20 so as to correspond to the horizontal guide rail 34 so that the slider 31 moves in the Y- And is fastened to the second core 20 so as to be able to reciprocate in a parallel direction.

Each of the sliders 31 is provided with an inclined surface 33 on the opposite side of the end where the undercut defining groove 36 is formed and is provided on both left and right sides of the inclined surface 33 in parallel with the extending direction of the inclined surface 33 And is provided with a protruded inclined guide rail 32. The side surface of the protruding block 50 has a plurality of inclined guide grooves 53 whose width gradually decreases from the upper surface 51a of the protruding block 50 to the lower surface 51b. The number of the guide grooves 53 is the same as the number of the sliders 31 and the sliders 31 are inserted into the guide grooves 53 one by one. Specifically, an inclined guide rail engaging groove 52 inclined in the same direction as the inclined guide rail 32 is provided inside the guide groove 53. When the protruding block 50 is inserted inside the concave groove 26 so that the inclined guide rail 32 is inserted into the inclined guide rail engaging groove 52 with the slider 31 fastened to the second core 20, (31) is fastened to the protruding block (50) so as to be slidable in an inclined direction with respect to the protruding block (50).

The horizontal guide rail 34 is inserted into the horizontal guide groove provided in the second core 20 and fastened to the second core 20 so that the projecting block 50 is concave in the direction parallel to the Z axis It can not move in the direction parallel to the Z-axis along the protruding block 50 when the second movement is made, as it protrudes from the groove 26 or is inserted into the concave groove 26. Therefore, when the first core 13 and the second core 20 come into close contact with each other, the protruding block 50 is pushed by the first core 13 to be inserted into the concave groove 26 of the second core 20 And the slider 31 is pushed by the protruding block 50 and moves in parallel with the Y axis to move to the first position. On the other hand, when the first core 13 and the second core 20 come into close contact with each other, the protruding block 50 moves in the direction protruding from the second core concave groove 26, The slider 31 is pulled by the protruding block 50 and moves in parallel with the Y axis to move to the second position.

Meanwhile, although the slider 31 shown in FIG. 3 has one undercut defining groove 36, the present invention is not limited thereto. For example, a plurality of undercut defining grooves may be formed in one slider, and the shapes of the plurality of undercut defining grooves may be the same or different. In addition, the ten sliders 31 shown in Figs. 2 and 3 have the same undercut defining grooves 36, but each slider may have undercut defining grooves of different shapes, and two to three sliders Type undercut limiting grooves may be distributed.

Referring again to FIGS. 1 and 4, the second core 20 is formed with a plurality of refrigerant channels 22 extending in parallel with the Y-axis. The refrigerant passage 22 is formed below the concave groove 26 so as to avoid the spring support pin 40 and the guide pin 45. However, since the structure of the inside of the second core 20 is simpler and the free space is wider than that of the injection molding die using the inclined deforming pin, a sufficient number of refrigerant channels can be formed in the second core 20 have. As a result, the molten resin injected into the cavity can be rapidly cured and the productivity of the injection molded article 1 is improved.

Figs. 5 and 6 are sectional views sequentially showing the operation of the protruding block and the slider, and Fig. 2 is a cut-away view along the line B-B. 5, when the first core 13 (see Fig. 1) and the second core 20 are brought into close contact, the protruding block 50 is inserted enough to contact the bottom of the concave groove 26, The slider 31 is pushed by the protruding block 50 to move in parallel with the Y axis to the first position and the first core 13, the second core 20 and the plurality of sliders 31 So that a cavity is formed. When the molten resin is injected into the cavity and cured, the injection product 1 is molded.

6, when the molten resin is hardened and the first core 13 and the second core 20 are brought into close contact with each other after the molding 1 is molded, the protruding block 50 is separated from the concave groove 26 And the slider 31 fastened to the protruding block 50 is pulled by the protruding block 50 and moves in parallel with the Y axis to move to the second position. 3) of the undercut 3 (see FIG. 3) and the undercut peripheral confinement surface 35 (see FIG. 3) are located on the second confining surface 24 (see FIG. 1) ). Thereafter, the injection material 1 is pushed up by the simple millefine extending parallel to the Z axis and separated from the second confinement surface 24, and the workpiece 1 separated from the second confinement surface 24 by the operator Are collected.

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: Injection 3: Undercut
10: injection molding die 13: first core
20: second core 22: refrigerant passage
24: second limiting surface 30: undercut processing unit
31: Slider 36: Undercut limiting groove
45: guide pin 50: protruding block

Claims

An injection molding die for molding an injection molding having an empty shape in the middle and an undercut on a side,
A first core having a first defining surface defining a side surface shape of the molded article; A second core having a second defining surface defining an opposite side surface shape of the injection molded body and having a concave groove in the middle; And an undercut processing unit that defines a shape of the undercut and is spaced apart from the undercut so that the mold can be taken out of the injection mold when the first core and the second core are separated from each other,
Wherein the undercut processing unit includes a guide which is inserted into a recessed groove of the second core and is in contact with the first core and which is inclined so that a width from an upper surface contacting with the first core to a lower surface contacting the second core gradually decreases A protruding block having a side with a groove and protruding in the direction of the first core; And
And a slider which is located in the concave groove and which is supported by the second core so as to define a shape of the undercut and slidable in a guide groove of the protrusion block, And an injection molding die.

The method according to claim 1,
The protruding block is elastically biased in a direction protruding toward the first core,
Wherein the slider has an undercut limiting groove that defines a shape of the undercut, and the slider has a first position where the undercut limiting groove is connected to the second limiting surface, and a second position where the undercut limiting groove is spaced apart from the second limiting surface. Wherein the first and second molds are reciprocally movable between positions.

3. The method of claim 2,
When the first core and the second core are brought into close contact with each other, the protruding block is pushed by the first core to move in the direction of insertion into the concave groove, and the slider is pushed by the protruding block to move to the first position , And when the first core and the second core are separated from each other, the protruding block moves in a direction protruding from the concave groove, and the slider is pulled by the protruding block to move to the second position Injection molding mold.

3. The method of claim 2,
Wherein a plurality of the undercut defining grooves are formed in the slider, and the shapes of the plurality of undercut defining grooves are the same or different.

3. The method of claim 2,
The undercut processing unit includes: a spring inserted into a spring insertion groove provided in the second core to elastically support the protruding block; And a spring support pin extending through the spring and having one side fixed to the second core and the other side slidably fitted to the protruding block. .

The method according to claim 1,
Wherein the undercut processing unit further comprises a guide pin slidably fitted on one side of the second core and the other side fixed to the projecting block,
Wherein a stopper is provided on the second core to limit a protruding range of the protruding block by restricting a movement range of the second core when the end of the guide pin is blocked.

The method according to claim 1,
Wherein the undercut processing unit further comprises a damper interposed between the protruding block and the second core, the damper being made of an elastic body for absorbing an impact when the protruding block collides with the second core Molding mold.

The method according to claim 1,
A plurality of sliders are provided,
And the plurality of sliders are fastened to the protruding block.