KR100713178B1 - Injection Unit with Gas Plug - Google Patents

Abstract

The present invention relates to an injection apparatus for injecting the resin supplied through the hopper by a screw formed in the barrel, by smoothly discharging the gas or water vapor generated in the barrel at a high temperature and high pressure during the injection of the resin, etc. The purpose of the present invention is to improve the formability by preventing the combustion of gas, incomplete molding of the molded article, and decrease in transparency. In order to achieve the above object, the injection apparatus according to the present invention has a through hole formed in an upper portion of the barrel, and is fitted with a tightly coupled through hole. It is done.

Gas Plug, Through Hole, Plug Head, Plug Body, Plug End, Vent Hole

Description

Injection Unit with Gas Plug {Injection Unit with Gas Plug}

Figure 1a is a vertical sectional view of the injection apparatus according to the present invention.

FIG. 1B is an enlarged cross sectional view of the gas plug portion shown in FIG. 1A; FIG.

2 is a perspective view of a gas plug according to the present invention.

3 is a sectional view taken along the line A-A 'of the plug end shown in FIG.

Figure 4 is a perspective view showing another embodiment of a gas plug according to the present invention.

<Description of main members in drawing>

3: hopper 4: screw

5: barrel

10: heater 20: through hole

21; Upper through hole 22: Lower through hole

40 gas plug 41 plug head

42: plug body 43: plug end

51: primary vent 52: vent hole

53: secondary vent

The present invention relates to a gas bleed nozzle installed in a barrel applied to the injection device, and more particularly, the installation defect rate of the injection molded product through the discharge of bubbles and gas generated during the metering by installing a gas plug outside the barrel of the injection device It relates to an injection apparatus aimed at reducing pressure.

In general, in the injection molding machine, the injection device is a molding condition in the mold after the resin supplied through the hopper is melted using shear heat and heater heat between the screw rotating by the hydraulic motor or the electric motor and the barrel wound the heater. Refers to a device for injecting at a pressure and speed suitable for the

The resin used in injection molding usually contains water, and vaporizes in a hot barrel to generate water vapor, while the resin is decomposed by excessive heat and shear force to generate gas.

In injection molding apparatus, gas is usually generated in the barrel due to the inherent characteristics of the molding material. For this reason, moldability, bubbles, and burnout, which are defective factors of the molded products, are generated, thereby reducing moldability. It is causing a problem.

Specifically, the state of the solid resin supplied to the hopper is caused by the shear heat generated through the rotation of the screw and the heater heat supplied from the outside of the barrel. The resin in the solid state is conveyed to the front end of the screw while most of the solid state is mixed with air in the supply portion of the screw.

The supply part receives heat from the heater and shear heat due to the relative movement of the screw and the barrel. The phase change progresses gradually from the solid state to the liquid state as it is transferred to the compression unit. The resin transferred through the supply part receives a compressive force while passing through the compression part of the screw whose transfer area changes rapidly, and the resin in the solid state causes a phase change to the liquid state. At this time, due to the rapid increase in temperature and shear force, the water contained in the resin is vaporized to become a water vapor state, and a large amount of gas is generated by thermal decomposition of the resin.

Water vapor, pyrolysis gas and a part of the gas that enters the resin through the hopper move toward the hopper which is relatively low pressure relative to the pressure of the screw compression part, and are discharged through the hopper. The resin passes through the metering part of the screw, which is a low pressure part compared to the pressure of the compression part, and accumulates at the front end of the screw head.

Resin and gas accumulated in the front end of the screw are injected into the mold by the advancement of the screw. In this case, the gas is carbonized by the high-speed injection or interrupts the flow of the resin, which may affect the appearance of the molded product or reduce transparency. .

Therefore, there has been a great demand for the development of an injection apparatus capable of removing gas or water vapor generated in the barrel of the injection apparatus from the inside of the barrel.

Therefore, the present invention is to solve the above problems by forming a gas nozzle on the top of the barrel to facilitate the discharge of gas and water vapor generated during the compression and metering of the resin by the rotation of the screw, thereby to the front end of the screw head It is an object to improve the formability by significantly reducing the amount of gas to be moved to prevent unmolding and bubbles in the molded article.

Hereinafter, with reference to the accompanying drawings with respect to the configuration of the preferred embodiment of the injection apparatus according to the present invention will be described in detail.

Figure 1a is a vertical sectional view of the injection apparatus according to the present invention. The hopper 3 is located in the supply unit 60 of the injection apparatus and functions to supply a material such as resin to be injected. Thus, the resin supplied through the hopper 3 is transferred to the barrel 5 by a screw 4. Compressed inside to move forward.

The resin is placed at a high pressure while passing through the supply unit 60, the compression unit 61, and the metering unit 62 of the injection apparatus, and at the same time, the resin is heated by the heat supplied to the barrel 5 by the external heater 10. As it is put into the state, it transitions to the molten state and emits a large amount of gas and water vapor and is injected into the mold.

As shown in FIG. 1A, the injection apparatus according to the present invention is characterized in that a through hole 20 is formed in the upper part of the barrel 5 and a gas plug 40 is installed in the through hole 20. Therefore, the gas and water vapor generated in the barrel 5 can be released to the outside.

Figure 1b shows only an enlarged portion of the gas plug 40 according to the present invention shown in Figure 1a.

The gas plug 40 has a cylindrical shape as a whole and the plug head 41, the plug body 42, and the plug end portion 43 are integrally formed while the diameter of the gas plug is intermittently reduced, and the plug head 41 and the plug are integrally formed. A secondary vent 53 penetrating the body 42 and the central portion of the plug end 43 in the longitudinal direction is provided, and a vent hole 52 is formed in the plug end 43, and the vent hole 52 is provided. It is connected to the primary vent 51 and the secondary vent 53.

The plug head 41 is formed in a flat cylindrical shape and is seated on the upper surface of the barrel 5. Four screw holes are formed symmetrically at the center thereof, and thus the barrel 5 and the riveting method are used. It is firmly combined.

The plug body 42 is formed integrally with the plug head 41 and has a cylindrical shape as a whole. The lower surface of the plug body 42 is locked to the lower surface of the upper through hole 21 to be described later.

The plug end portion 43 is formed integrally with the plug body 42, and is formed in the shape of a polygonal column such as a cylinder or a hexagon, an octagon, and the like, and a plurality of vent holes 52 are formed in the radial direction.

The upper through hole 21 corresponds to an upper portion of the through hole formed in the barrel 5 and is formed so that the above-described plug body 42 can be fitted with the inner diameter coinciding with the outer diameter of the plug body 42. As described above, the lower surface of the plug body 42 is caught and seated on the lower surface of the upper through hole 21.

In Figure 1b, the shape of the upper through-hole 21 and the plug body 42 is shown only in the shape of a cylinder, but in addition, it is possible to form a variety of shapes, such as a square pillar, a pentagonal pillar, a hexagonal pillar, and such embodiments All of them will also fall within the scope of the present invention.

The lower through hole 22 corresponds to the lower portion of the through hole formed in the barrel 5 and is formed as a single body continuously with the upper through hole 21. On the other hand, since the lower through hole 22 has a cylindrical shape as a whole, and the plug end portion 43 is formed of a prism, a gap is generated between the inner surface of the lower through hole 22 and the outer surface of the plug end portion 43. The gap is to form a primary vent 51 to be described later.

The primary vent 51 is a gap formed by the lower through hole 22 and the plug end 43, and is preferably formed to a size of 1/10 mm or less. 5) After being introduced into the primary vent 51 due to the high pressure inside, it is discharged to the outside along the secondary vent 53 connected to the vent hole 52 through the vent hole 52 of the plug end 43. .

The secondary vent 53 has a constant diameter and is formed while continuously passing through the central portions of the plug head 41, the plug body 42, and the plug end portion 43 to reach the vent hole 52.

FIG. 2 is a perspective view of the gas plug 40 according to the present invention, which is roughly divided into a plug head 41, a plug body 42, and a plug end 43 as described in FIG. 1B.

Four screw holes 45 are formed to face each other centering on the secondary vents 53, and rivets or bolts are inserted into the screw holes 45 to firmly couple the plug head 41 to the barrel 5. It works.

As shown in FIG. 2, four screw holes 45 are formed in the plug head 41. The plug head 41 has a flat cylindrical shape as a whole. Of course, the shape of the plug head 41 may be in addition to the shape of the cylinder shown in FIG. It will be described as merely a design change of the present invention.

Since the plug body 42 is formed integrally with the plug head 41 and the plug end 43 below, the plug body 42 can be formed in various shapes such as a cylinder or a prismatic pole, as described above with reference to FIG. 1B. The description will be omitted.

The plug end portion 43 has a hexagonal column shape as shown in FIG. 2, and vent holes 52 are formed in the radial direction on each side thereof, and the bottom of the plug end portion 43 is extruded from the inside of the barrel 5. It corresponds to a part in direct contact with the resin to be. The shape of the plug end 43 may be, of course, shaped like an octagonal pillar in addition to the hexagonal pillar shown in FIG.

The secondary vent 53 is formed through the plug head 41, the plug body 42, the plug end portion 43 to a predetermined diameter to reach the vent hole 52 has already been described in Figure 1b.

3 is a cross-sectional view in the horizontal direction at the position of the vent hole 52 with respect to the plug end 43 shown in FIG.

Since the plug end portion 43 is formed in the shape of a hexagonal column as a whole, its cross section has a hexagonal shape and each corner is formed to contact the inner surface of the lower through hole 22.

The vent hole 52 is a hole of a circular cross section formed while penetrating the plug end 43 radially at each side of the plug end 43, and each vent hole 52 is formed in the longitudinal direction of the plug end 43. Converging to the secondary vents 53 are formed to be connected to each other. Therefore, the gas flowing into each vent hole 52 is collected at the center of the plug end 43 and discharged to the outside through the secondary vent 53.

In FIG. 3, the number of the vent holes 52 is 6, but this is only an embodiment of the present invention. The number of the vent holes 52 is the amount of gas, water vapor, etc. generated in the barrel 5 or the plug end portion. In consideration of the shape of (43) and the like, the number can be increased or decreased by an appropriate number, and preferably about 4 to 12 are suitable.

The primary vent 51 is formed as a space formed by a gap formed by the side of the plug end 43 and the inner surface of the lower through hole 22, and serves as a passage through which gas inside the barrel 5 is primarily introduced. Will be in charge. Although the diameter of the primary vent 51 can be adjusted according to the characteristics of the molding material to be extruded, it is appropriate to set the size of 5/100 mm.

4 is a perspective view showing another embodiment of a gas plug according to the present invention.

Since the description of the plug head 41 and the plug body 42 is the same as in FIG. 2, the description thereof will be omitted.

The plug end portion 43a has a cylindrical shape as a whole, and the outer diameter of the plug end portion 43a is lower through hole 22 so that the plug end portion 43a may be in close contact with the inner surface of the lower through hole 22. It is formed to match the inner diameter of.

Therefore, the gas generated inside the barrel 5 can be discharged only through the concave vent 54 to be described later.

The concave vent 54 is formed in the longitudinal direction on the side of the plug end 43a to reach the vent hole 52 from the inside of the barrel 5 and has a semicircular cross-sectional shape. The concave vent 54 acts to allow gas, etc. generated inside the barrel 5 to flow out of the vent hole 52 primarily, and the diameter of the concave vent 54 may be equal to that of the primary vent 51 described above. Similarly, forming about 1/10 mm is preferable, and forming about 5/100 mm is appropriate.

In FIG. 4, the number of the concave vents 54 is illustrated as four, but the number of the concave vents 54 may be increased or decreased depending on the amount of gas generated.

Although not shown directly in FIGS. 2 and 4, the plug end 43 may be manufactured separately from the plug body 42, and in particular, when the plug end 43 is formed as shown in FIG. 4, a concave vent ( By making the plug end portion 43a of various types different from each other with the number of plugs 42 as a separate body from the plug body 42, it is possible to apply variously to the amount of gas generated without replacing the entire gas plug 40. Could be.

The present invention constructed and functioning as described above, in the injection device using a screw, forms a gas plug on the top of the barrel to smoothly discharge the gas and water vapor generated during the compression and metering of the resin due to the rotation of the screw. In this way, the amount of gas that moves to the front end of the screw head is greatly reduced, thereby preventing the occurrence of unmolding, bubbles, etc., thereby improving the formability.

Although the invention has been described with reference to the preferred embodiments mentioned above, various other possible modifications and variations can be made without departing from the spirit and scope of the invention. Accordingly, the appended claims are intended to cover such modifications and variations as fall within the true scope of the invention.

Claims (8)

In the injection device for injecting the resin and the like supplied into the barrel through the hopper by a screw, Through hole 20 formed in the upper portion of the barrel (5), The plug head 41 includes a gas plug 40 that is tightly fitted into the through hole 20 and is coupled to the outer surface of the barrel 5. The through hole 20 is composed of an upper through hole 21 and a lower through hole 22 which has a smaller diameter than the upper through hole 21 and is continuously formed downward from the upper through hole 21. Become, The gas plug 40 has a plug body 42 and a plug end portion 43 having different diameters, so that the plug body 42 is caught on the upper surface of the lower through hole 22 and is seated. Injection device equipped with a. delete The method of claim 1, The gas plug 40 is equipped with a gas plug, characterized in that the secondary vent 53 is continuously formed through the plug head 41, the plug body 42 and the plug end portion 43 is continuously constructed. One injection unit. The method of claim 3, wherein At least one vent hole 52 is formed in the plug end 43 in a radial direction, and an outer end of the vent hole 52 is provided by a lower through hole 22 and the plug end 43. It is connected to the primary vent (51), the inner end of the vent hole 52, the injection device equipped with a gas plug, characterized in that connected to the secondary vent (53). The method of claim 4, wherein Injection device equipped with a gas plug, characterized in that the primary vent (51) is 1 / 10mm or less. The method of claim 3, wherein The plug end portion 43 has a cylindrical shape as a whole, and at least one vent hole 52 is formed in a radial direction, and the plug end portion 43 has a length from the inlet of the vent hole 52 in the longitudinal direction. Injection device equipped with a gas plug, characterized in that at least one concave vent (54) is formed in a semi-circular cross-sectional shape to the end of the plug end (43). The method according to any one of claims 4 to 6, The gas plug 40 is at least one injection device equipped with a gas plug, characterized in that at least one. The method of claim 6, Injection device equipped with a gas plug, characterized in that the concave vent (54) is 1 / 10mm or less.

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