KR101340072B1 - Mold for injection molding pillar-typed product - Google Patents

Abstract

An injection molding die is disclosed that can produce a columnar product by an injection molding method. The disclosed injection molding die may include an upper core and a lower core, in which a columnar cavity is formed when closely contacted with each other, a resin injection nozzle for injecting molten resin into the cavity, A piston inserted into the cavity through an opening formed opposite the resin injection nozzle and linearly reciprocating between a first position relatively close to the resin injection nozzle and a second position relatively spaced from the resin injection nozzle ( piston) and a pneumatic cylinder for linearly driving the piston. The injection molding die is configured to inject molten resin from the resin injection nozzle when the piston is in the first position, and to move the piston to the second position by being pushed by the injection pressure of the molten resin.

Description

Mold for injection molding pillar-typed product

The present invention relates to an injection molding die, and more particularly to a mold for injection molding a columnar product.

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.

1 is a perspective view showing an example of a columnar product, specifically, the product 5 shown in FIG. 1 is a member constituting a neck of a stand supporting an LCD TV. This product 5 is a columnar product, and rigidity capable of supporting a heavy LCD TV main body is required. However, when the stand-neck product 5 is produced by a conventional general injection molding process, a product having sufficient rigidity cannot be obtained due to uneven cooling temperature and internal bubble generation. Accordingly, the stand neck product 5 is first produced by insert molding in which the cylinder 7 is produced by extrusion processing first, and the resin is injected and cured while the cylinder 7 is inserted into a mold. Has been produced. However, when the cylinder 7 is formed by extrusion, there is a problem that productivity is lowered and production cost is increased because post-processing such as cutting after extrusion is added.

The present invention provides an injection molding mold capable of producing a columnar product by an injection molding method.

In addition, according to an embodiment of the present invention provides an injection molding die that can be produced by injection molding a plurality of columnar products at the same time.

In addition, according to an embodiment of the present invention provides an injection molding mold that can be produced by injection molding a column-shaped product of which the diameter of the middle portion is smaller than the diameter of the upper and lower portions.

The present invention, the upper core (lower core), the resin injection nozzle (nozzle) for injecting the molten resin into the cavity, the resin is formed when the column-shaped cavity (cavity) is formed in close contact with each other A piston which is inserted into the cavity through an opening formed opposite the injection nozzle and is linearly reciprocable between a first position relatively close to the resin injection nozzle and a second position relatively spaced from the resin injection nozzle. And a pneumatic cylinder for linearly driving the piston, wherein the molten resin is injected from the resin injection nozzle when the piston is in the first position, and the piston is moved to the second position by being pushed by the injection pressure of the molten resin. It is composed.

A plurality of molding units including the cavity, the resin injection nozzle, and the piston may be provided.

The injection molding die of the present invention may further include a piston cooling passage formed inside the piston such that refrigerant flows into the piston to exchange heat with the molten resin injected into the cavity and flow out of the piston.

The injection molding die of the present invention may further include a core cooling passage formed around the cavity such that the refrigerant exchanges heat with the molten resin injected into the cavity.

The inner diameter of the cavity may be constant along the longitudinal direction of the cavity.

The cavity may be defined by a lower core through-hole penetrating the lower core in a vertical direction and a lower side of the upper core in close contact with the lower core to close the upper side of the lower core through-hole.

The columnar product formed by curing the molten resin injected into the cavity may be spaced apart from the lower core to open the upper side of the lower core throughhole and move the piston from the second position to the first position. And may exit from the lower core aperture.

The inner diameter of one point located between both ends of the cavity along the longitudinal direction of the cavity is the smallest of the inner diameter of the cavity, and the diameter of the piston is a size that passes through the inner diameter of the smallest cavity without play. It may be constant in the longitudinal direction of the piston.

According to the injection molding die of the present invention, one or a plurality of columnar products can be produced at the same time by the injection molding method. Thus, productivity is improved and production costs are reduced.

In addition, according to the embodiment of the present invention, since the diameter of the middle portion may be produced by injection molding a column-shaped product smaller than the diameter of the upper portion and the lower portion at a time, the effect of improving productivity and reducing production costs is greater.

1 is a perspective view showing an example of a columnar product.
2 is a cross-sectional view illustrating an injection molding die according to an embodiment of the present invention.
Figure 3 is a cross-sectional view showing a state that the columnar product is taken out from the injection molding mold according to an embodiment of the present invention.
Figure 4 is a cross-sectional view showing an injection molding mold according to another embodiment of the present invention.
Figure 5 is a cross-sectional view showing an injection molding mold according to another embodiment of the present invention.

Hereinafter, an injection molding mold for injection molding a columnar product according to an exemplary 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 the terms should be made based on the contents throughout the specification.

Figure 2 is a cross-sectional view showing an injection molding mold according to an embodiment of the present invention, Figure 3 is a cross-sectional view showing a state in which the columnar product is taken out from the injection molding mold according to an embodiment of the present invention.

2 and 3, the injection molding mold 10 according to an embodiment of the present invention is a mold capable of producing a columnar product 7 by injection molding, the upper core 12 and the lower core ( 20), a resin injection nozzle 15, a piston 30, and a pneumatic cylinder 52 (see FIG. 4). When the upper core 12 and the lower core 20 are in close contact with each other, a cavity 22 having a columnar shape is formed. Although not clearly shown in FIGS. 2 and 3, the upper core 12 may be coupled to the upper disc (not shown), and the lower core 20 may be coupled to the lower disc (not shown).

Specifically, the cavity 22 has a lower core through hole formed to penetrate the lower core 20 in the vertical direction, and a lower side surface of the upper core 12 in close contact with the lower core 20 to close the upper side of the lower core through hole. It is limited by. The inner diameter of the cavity 22 is constant along the longitudinal direction of the cavity 22, that is, the vertical direction.

The resin injection nozzle 15 is for injecting molten resin into the cavity 22, and is fixedly coupled to the upper core 12, when the upper core 12 and the lower core 20 are brought into close contact with each other. The distal end extends to the top of the cavity 22. The piston 30 is inserted into the cavity 22 through an opening formed opposite the resin injection nozzle 15, that is, on the lower side of the lower core 20. The piston 30 is capable of linear reciprocation between a first position relatively close to the resin injection nozzle 15 and a second position relatively spaced from the resin injection nozzle 15. The position of the piston 30 in the phantom line of FIG. 2 or the position of the piston 30 in FIG. 3 represents the first position of the piston 30, and the position of the piston 30 in the solid line of FIG. 2 is the second position. Indicates a location.

The diameter of the piston 30 is a size that passes through the inner diameter of the cavity 22 constant in the vertical direction without play, and is constant in the longitudinal direction of the piston 30. Therefore, even if molten resin is injected into the cavity 22, the molten resin does not leak between the inner circumferential surface of the cavity 22 and the outer circumferential surface of the piston 30. The lower end of the piston 30 is formed with a latching jaw 32 of which the diameter extends in the radial direction. The locking jaw 32 may not enter the cavity 22. When the piston 30 is raised, the locking jaw 32 may rise until it hits the lower core 20 and is blocked, and the position of the piston 30 at that time becomes the first position. The piston 30 is supported by the piston support member 35. The pneumatic cylinder 52 (see FIG. 4) can be driven to raise and lower the piston support member 35 in the vertical direction. The pneumatic cylinder 52 is demonstrated in detail with reference to FIG.

The injection molding die 10 further includes a piston cooling passage 37 and a core cooling passage 25 as cooling means for curing the hot molten resin injected into the cavity 22. Specifically, the piston cooling passage 37 is formed to be connected in line with the inside of the piston cone member 35 and the piston 30. The refrigerant flowing along the piston cooling channel 37 in the piston support member 35 flows into the piston 30, heat exchanges with the molten resin injected into the cavity 22, and flows out of the piston 30. Although not shown in detail in FIGS. 2 and 3, the refrigerant flows into the piston cooling passage 37 from the outside of the piston support member 35, flows into the piston 30, and then flows out of the piston support member 35 after heat exchange. do.

The core cooling passage 25 has a path that wraps around the cavity 22 like a coil spring. Although not shown in detail in FIGS. 2 and 3, the refrigerant flows into the lower core 20 from the outside of the lower core 20 and passes through a path that surrounds the cavity 22 and is injected into the cavity 22. After heat exchange with the outflow to the outside of the lower core (20). The refrigerant flowing through the piston cooling passage 37 and the refrigerant flowing through the core cooling passage 25 may be the same kind or different kinds.

Hereinafter, a method of injection molding a columnar product using the injection molding die 10 will be described. First, the upper core 12 is in close contact with the upper side of the lower core 20 in a state where the piston 30 is raised to the first position (see the imaginary line in FIG. 2). Then, the molten resin of high temperature and high pressure is ejected through the resin injection nozzle 15. As the high pressure molten resin flows into the cavity 22, the piston 30 is slowly pushed down to the second position (see solid line in FIG. 2) by the pressure of the molten resin. As the piston 30 descends, the cavity 22 gradually increases, and the molten resin ejected from the resin injection nozzle 15 is gradually filled. Thus, no turbulence of the resin or bubbles in the resin are generated in the cavity 22, and it is comparable to the product of the same shape formed by extrusion molding in spite of the columnar thick product 7 formed by injection molding. It can have a strong stiffness.

The high temperature molten resin is cured by cooling through the refrigerant flowing along the piston cooling channel 37 and the refrigerant flowing along the core cooling channel 25 to form the columnar product 7 in the cavity 22. The extraction process of the product 7 firstly opens the upper side of the lower core through hole by separating the upper core 12 from the lower core 20. As shown in FIG. 3, when the piston 30 is moved from the second position to the first position, the cylindrical product 7 exits from the lower core through hole and protrudes and is pulled out above the lower core 20. .

Figure 4 is a cross-sectional view showing an injection molding mold according to another embodiment of the present invention. Referring to FIG. 4, the injection molding die 50 according to another embodiment of the present invention includes a plurality of molding units including a cavity 22, a resin injection nozzle 15, and a piston 30. Specifically, a plurality of lower core through holes corresponding to the cavity 22 are formed in the lower core 20, and resins having the same number of resins as the cavity 22 are used to inject molten resin into each cavity 22. The injection nozzle 15 is coupled to and supported by the upper core 12, and the piston 30 having the same number as the cavity 22 and the piston support member 35 is inserted into each cavity 22 to move up and down. Is supported coupled to.

The piston support member 35 is connected to the pneumatic cylinder 52 and can be lifted up and down, and the plurality of pistons 30 can be lifted up and down simultaneously to the first position or the second position by the lift up of the piston support member 35. With this structure, the plurality of columnar products 7 (see FIG. 3) can be simultaneously formed by elevating the plurality of pistons 30 with one pneumatic cylinder 52.

The pneumatic cylinder 52 has a cylinder body 53 and a rod 55 for elevating with the pressure of the air flowing into or out of the cylinder body 53. The cylinder body 53 is fixedly supported by the lower core 20, and the distal end of the rod 55 is coupled to the piston support member 35. On the other hand, the piston cooling passage 37 is connected in series so that the refrigerant passes through the plurality of pistons 30 sequentially, and the core cooling passage 25 allows the refrigerant to sequentially pass around the plurality of cavities 22. Are connected in line.

Figure 5 is a cross-sectional view showing an injection molding mold according to another embodiment of the present invention. Referring to FIG. 5, in the injection molding mold 60 according to another exemplary embodiment of the present invention, both the recessed grooves formed on the upper side of the lower core 70 and the recessed grooves formed on the lower side of the upper core 62 are both cores. When the 62 and 70 are in close contact with each other, the cavity 72 is formed. The cavity 72 is formed such that the inner diameter D1 of one point located between both ends of the cavity in the longitudinal direction is the smallest of the inner diameter of the cavity 72, and the inner diameter of the cavity 72 increases toward both ends.

The resin injection nozzle 65 for injecting molten resin into the cavity 72 is coupled to the upper core 62, and the end of the resin injection nozzle 65 extends to one end in the longitudinal direction of the cavity 72. The piston 80 enters the cavity 72 from the opposite side of the resin injection nozzle 65 and is capable of linear reciprocation in the horizontal direction between the first position shown by the virtual line and the second position shown by the solid line. The piston 80 has a locking step 82 for setting the entry limit of the piston (80). The piston 80 is coupled to and supported by a piston support member 85 driven by a pneumatic cylinder (not shown), and a piston cooling passage 87 is formed in the piston to allow refrigerant to flow and exchange heat.

Although not shown in detail in FIG. 5, the injection molding die 60 may include a plurality of molding units including a cavity 72, a resin injection nozzle 65, and a piston 80 in a direction perpendicular to FIG. 5. Piston 80 may be connected in series with the piston support member 85 extending in the direction perpendicular to FIG. The refrigerant flowing in the piston 80 along the piston cooling channel 87 flows in from one side of the piston support member 85 and sequentially moves to the other side of the piston support member 85 via the plurality of pistons 80. Spills.

The diameter D2 of the piston 80 is a size that passes through the smallest cavity inner diameter D1 inside the cavity 72 without play, and is constant in the longitudinal direction of the piston 80. Therefore, even if the molten resin is ejected to the cavity 72 so that the piston 80 retracts from the first position to the second position, the molten resin until the front end of the piston 80 passes the smallest cavity inner diameter D1. Cannot diffuse rapidly inside the cavity 22.

Hereinafter, a method of injection molding a columnar product using the injection molding die 60 will be described. First, the upper core 62 is brought into close contact with the upper side of the lower core 70, and the piston 80 is horizontally moved to the first position (see the imaginary line in FIG. 5). Then, the molten resin of high temperature and high pressure is ejected through the resin injection nozzle 65. As the high pressure molten resin flows into the cavity 72, the piston 80 retreats slowly to the second position (see solid line in FIG. 5) by the pressure of the molten resin. As the piston 80 descends, the cavity 72 gradually increases, and the molten resin ejected from the resin injection nozzle 65 is gradually filled and cooled to form a pillar-shaped product having a diameter of the middle portion smaller than the diameter of the upper and lower portions ( Not shown) is formed in the cavity 72. The molded article can be spaced apart from the upper core 62 from the lower core 70 and the exposed product can be taken out by the operator's hand or by an automated work robot.

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.

10: injection molding mold 12: upper core
15: resin injection nozzle 20: lower core
22: cavity 25: core cooling flow path
30: piston 37: piston cooling flow path

Claims (8)

An upper core and a lower core in which a columnar cavity is formed when closely contacted with each other;
A resin injection nozzle for injecting molten resin into the cavity;
A piston inserted into the cavity through an opening formed opposite the resin injection nozzle and linearly reciprocating between a first position relatively close to the resin injection nozzle and a second position relatively spaced from the resin injection nozzle ( piston); And
A pneumatic cylinder for linearly driving the piston;
Molten resin is injected from the resin injection nozzle when the piston is in the first position, and the piston is moved to the second position by being pushed by the injection pressure of the molten resin,
The inner diameter of the cavity is constant along the longitudinal direction of the cavity,
The cavity is defined by a lower core through-hole penetrating the lower core in the vertical direction, and a lower side of the upper core in close contact with the lower core to close the upper side of the lower core through-hole. The method according to claim 1,
Injection molding die, characterized in that provided with a plurality of molding units consisting of the cavity, the resin injection nozzle, and the piston. The method according to claim 1,
And a piston cooling flow path formed inside the piston such that refrigerant flows into the piston to exchange heat with the molten resin injected into the cavity and flow out of the piston. The method according to claim 1,
And a core cooling flow path formed around the cavity such that the refrigerant exchanges heat with the molten resin injected into the cavity. delete delete The method according to claim 1,
The columnar product formed by curing the molten resin injected into the cavity may be spaced apart from the lower core to open the upper side of the lower core throughhole and move the piston from the second position to the first position. Injection molding die, characterized in that configured to exit from the lower core through-holes. An upper core and a lower core in which a columnar cavity is formed when closely contacted with each other;
A resin injection nozzle for injecting molten resin into the cavity;
A piston inserted into the cavity through an opening formed opposite the resin injection nozzle and linearly reciprocating between a first position relatively close to the resin injection nozzle and a second position relatively spaced from the resin injection nozzle ( piston); And
A pneumatic cylinder for linearly driving the piston;
Molten resin is injected from the resin injection nozzle when the piston is in the first position, and the piston is moved to the second position by being pushed by the injection pressure of the molten resin,
The inner diameter of one point located between both ends of the cavity along the longitudinal direction of the cavity is the smallest of the inner diameter of the cavity,
The diameter of the piston is a size that passes through the inner diameter of the smallest cavity without a gap, it is constant in the longitudinal direction of the piston, characterized in that the injection molding die.

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