KR101046078B1 - Injection Molding Equipment - Google Patents

Abstract

<Problem> It aims at shortening molding time, eliminating deformation and transfer nonuniformity of molded article as much as possible.

<Solution> Steam is supplied into the heat medium passage 12 of the female mold part 6, the cavity formation surface side of the female mold part 6 is heated, a temperature rise is started, and a mold clamp is performed. Then, when the cavity formation surface side reaches a predetermined temperature, the temperature increase is stopped and the molten synthetic resin J is injected into the cavity S in a predetermined amount. Thereafter, the pressurized gas is injected between the rear surface of the synthetic resin J and the cavity forming surface of the male mold portion 27, and pushed to the cavity forming surface to hold it therein. While holding this pressure, supply of cooling water is started in the heat medium passage 12, and the synthetic resin on the surface of the female mold part 6 is cured. When hardened to some extent, the injection of pressurization is stopped and the pressurized gas is discharged out of the apparatus, and when the discharge of the pressurized gas is finished out of the apparatus, cold air is injected between the back surface of the resin and the cavity forming surface of the male mold portion 27. do. Then, when the synthetic resin solidifies to an extent sufficient to take out, the mold is clamped.

Description

Injection Molding Equipment {INJECTION MOLDING DEVICE}

The present invention relates to an injection molding apparatus. Specifically, the present invention relates to an injection molding apparatus involving injection of pressurized gas between a synthetic resin in a cavity and a cavity forming surface.

Conventionally, for example, as disclosed in Patent Literature 1 and the like, a technique for heating the surface side cavity forming surface for molding the surface side of a molded article before injecting the molten synthetic resin to improve the transferability Is being proposed.

[Patent Document 1] Japanese Unexamined Patent Publication No. 6-254924

However, the molten synthetic resin moves in the cavity as it cools, so that sometimes it does not spread evenly to the distal end, or especially when the sheet thickness of the molded article becomes thin, the molten synthetic resin solidifies during the flow. There is a problem of throwing away, and in addition, the molding time is also long because the high frequency induction heating inductor is sandwiched between the stationary type and the movable type.

Then, in view of the said point, an object of this invention is to prevent deformation | transformation and transfer nonuniformity of a molded article as much as possible, and to shorten molding time.

To this end, the first invention comprises a female mold and a male mold, and after heating the cavity forming surface side of the female mold, the molten synthetic resin is injected into the cavity formed between the female mold and the male mold, and pressurized. An injection molding apparatus injecting gas into the cavity to push the surface of the synthetic resin onto the cavity-forming surface of the female mold to pressurize it, wherein the bottom surface of the cavity is formed of the bottom-forming body and the male mold. At least an upper end of the bottom forming body and an abutting portion of the bottom forming body and the male mold are formed in a frame shape along the abutting part and protruding upwardly to project into the cavity. A groove is formed between the mold and the male mold, and the molten synthetic resin is injected into the cavity. When a pressurized gas is injected between the back surface of the synthetic resin and the cavity forming surface of the male mold, the synthetic resin proceeds toward the butt portion of the bottom forming body and the male mold, and the synthetic resin at the tip end of the protrusion portion. It is characterized in that it comes in contact with the inside of the groove.

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2nd invention consists of a 1st space which extends the said cavity in a horizontal direction in the 1st invention, and a cylindrical 2nd space which extends in the vertical direction which communicated this 1st space, and makes the said 1st space the female. The bottom surface of the second space is formed by the mold base as the bottom forming body and the male mold, which are formed of a mold and the male mold, and the male mold is disposed on and fixed to an upper surface thereof. A second space is formed of the female mold, the male mold, and the mold body, and each of the upper end portions of the abutment portion between the mold body and the male mold protrudes upward from each other into the cavity so that the butt portion Therefore, it is characterized in that the grooves are formed by both protrusions by forming a frame shape and abutting both protrusions.
3rd invention consists of 1st invention which consists of the 1st space which extends the said cavity in a horizontal direction, and the cylindrical 2nd space which extends in the vertical direction which communicated this 1st space, Forming a female mold and the male mold, and forming a bottom surface of the second space by the mold body as the bottom forming body for placing and fixing the male mold on the upper surface and the male mold. The second space is formed of the female mold, the male mold, and the mold body, and the butt portion protrudes upwardly so as to be pushed into the cavity at an upper end of the mold body of the butt portion of the male mold. Therefore, the groove is formed between the protrusion and the male mold while being formed in a frame shape.

According to a fourth aspect of the present invention, in order to form an opening in a molded article in the first aspect, the top surface of a portion which is squeezed into the cavity and whose top portion is brought into contact with the female mold and is disposed on and fixed to the upper surface of the male mold is formed on the bottom surface. A bush constituting a sieve is disposed on and fixed to the upper surface of the male mold, and the protrusion is formed to be squeezed into the cavity at the outer circumference of the fixed portion of the bush, and between the protrusion and the male mold. The groove is formed in the above.
According to a fifth aspect of the present invention, in order to form an opening in a molded article in the first aspect of the invention, the top surface of a portion which is squeezed into the cavity and whose top portion is brought into contact with the female mold and is disposed on and fixed to the upper surface of the male mold is formed. The first protrusion and the upper surface of the male mold are arranged to fix a bush constituting a sieve on the upper surface of the male mold, and to be squeezed into the cavity at the outer circumference of the fixed portion of the bush as the protrusion. A second protrusion is formed to be pushed into the cavity so as to surround the protrusion from the outside, the groove is formed between the second protrusion and the first protrusion, and the first protrusion is formed on the outer periphery of the upper surface of the bush. The other groove | channel was formed also in between.

In a sixth invention, in the first invention, a bush as the bottom forming body is disposed on the upper surface of the male mold, and the protrusion is projected into the cavity by the upper peripheral portion of the bush. The grooves are formed between the side surfaces of the cavity, the molten synthetic resin is injected into the cavity, and the pressurized gas is injected between the back surface of the synthetic resin and the bush. It is characterized by entering into the groove beyond.

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In a seventh aspect of the present invention, a bush as the bottom forming body is fitted into a recess formed in the upper surface of the male mold in the first invention, and the first protrusion as the protrusion is pushed into the cavity by the upper peripheral portion of the bush. And a second projection projecting into the cavity to the upper periphery of the male opening forming the concave portion, protruding higher than the first projection, and forming the groove between the second projection and the first projection. When the molten synthetic resin is injected into the cavity, the molten synthetic resin is squeezed into the groove. Then, when the pressurized gas is supplied into the cavity, a pressurized gas layer is formed between the synthetic resin and the bush in the cavity. The upper end of the first projection of the bush, but the pressurized gas The pressure of the synthetic resin is pushed to the cavity forming surface of the female mold in the state not exceeding the second protrusion.

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In the eighth invention, in order to form a thin portion in the molded article in the first invention, the upper longitudinal section in which the upper portion is squeezed into the cavity has a trapezoidal shape in which the upper bottom is shorter than the lower bottom. A bush provided on the upper surface is further provided, and a protrusion having a quadrilateral portion substantially perpendicular to the quadrilateral portion of the bush is formed on the upper surface of the bush so as to slide into the cavity. When a synthetic resin is injected into the cavity and the pressurized gas is injected between the back surface of the synthetic resin and the cavity forming surface of the male mold, the pressurized gas extends beyond the top of the projecting portion to the quadrilateral portion of the projecting portion and the bush. And a pressurized gas which reaches the solid part formed by the quadrilateral part, and the pressurized gas which reaches the solid part is along the quadrilateral part of the bush. Standing under pressure so as to push up the synthetic resin is characterized in that for pressing the synthetic resin of the gap between the bushing and the upper surface of the female mold.

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In the ninth invention, in order to form a thin portion in the molded article in the first invention, the male thin portion having an upper end face in which the upper portion of the thin portion is trapped into the cavity has a trapezoidal shape whose upper bottom is shorter than the lower bottom. It is formed on the upper surface of the mold, to form a projection having a quadrilateral portion substantially perpendicular to the quadrilateral portion of the thin-film forming portion so as to be pushed into the cavity on the upper surface of the thin-film forming portion, the molten synthetic resin in the cavity When the pressurized gas is injected between the back surface of the synthetic resin and the cavity forming surface of the male mold, the pressurized gas extends over the top of the protrusion and to the quadrilateral portion of the protrusion and the thin film forming portion. The pressurized gas which is formed by the contact portion, and the pressurized gas that reaches the sump portion is the thin film forming portion Therefore, parts of affairs is characterized in that the pressure to the pushing pressure of the synthetic resin of the synthetic resin between said bakyukhyeong part of the upper surface and the female mold.

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According to a tenth aspect of the invention, in the eighth or ninth aspect, a tapered portion is formed at each of the top portions of the protrusions.

In the eleventh aspect of the present invention, in order to form a thin portion in the molded article in the first aspect, an upper longitudinal section in which an upper portion thereof is squeezed into the cavity exhibits a trapezoidal shape in which an upper bottom is shorter than a lower bottom. A bush is further provided on an upper surface, and each of the first protrusions is provided on the upper surface of the male mold located near the bush, and the first protrusion is formed to be pushed into the cavity. A second protrusion having a quadrilateral portion that is generally perpendicular to the quadrilateral portion of the protruding portion, the second protruding portion being plunged into the cavity; When injected between the surface and the pressurized gas, the first protrusion is over the second protrusion and the first protrusion. The pressurized gas is pushed to push the back surface of the synthetic resin in a direction orthogonal to the quadrangle of the first protrusion and a direction orthogonal to the quadrangle of the second protrusion, and is pressed to the quadrilateral portion of the first protrusion. And pressurizing the synthetic resin between the female mold and the female mold.

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The twelfth invention further provides a bush on the upper surface of the male mold, with a bush in which the upper part is brought into the cavity to contact the female mold to form an opening in the first invention, and the bush is formed on the upper surface of the male mold. Forming a projection to be squeezed into the cavity so as to surround the cavity, forming a groove between the bush and the projection, injecting the molten synthetic resin into the cavity, and injecting the pressurized gas into the back surface of the synthetic resin and the male mold. When injected between the cavity forming surface of the resin, the synthetic resin is brought into contact with the groove by the pressurization of the pressurized gas, and the pressurized gas flows into a portion other than the groove by allowing the synthetic resin to enter the groove so that the pressurized gas flows into the groove. Surrounding the bush by increasing the volume of the pressurized gas. By increasing the density of the synthetic resin of the cured resin, characterized in that to prevent the pressurized gas is drawn up along the side of the bush.
The thirteenth invention further comprises a bush on the upper surface of the male mold, with a bush in which the upper part contacts the female mold to form an opening in the molded article in the first invention, and the inside of the bush in the outer peripheral portion of the upper surface of the bush. A first groove is formed between the first protrusion and the first protrusion, and a second protrusion is formed on the upper surface of the male mold to squeeze into the cavity so as to surround the first protrusion from the outside; and the second A second groove is formed between the protrusion and the first protrusion, the molten synthetic resin is injected into the cavity, and the pressurized gas is injected between the back surface of the synthetic resin and the male mold cavity forming surface. The synthetic resin is brought into contact with the second groove beyond the second protrusion by the pressurization of the pressurized gas. It proceeds to reach the first groove over the first protrusion, and the pressurized gas flows to the parts other than the first groove and the second groove by making the synthetic resin into the first groove and the second groove. By increasing the volume of the pressurized gas in the cavity, the density of the synthetic resin around the bush is increased and cured to prevent the pressurized gas from being drawn along the side of the bush.
The fourteenth invention further includes a bush in which the upper part of the first mold contacts the female mold in order to form an opening in the molded article in the first invention, and further includes a bush in the upper peripheral portion of the upper surface of the bush. A groove is formed between the projecting part and the projecting part, and the molten synthetic resin is injected into the cavity, and the pressurized gas is injected between the back surface of the synthetic resin and the cavity forming surface of the male mold. The contact with the protrusion by the pressurization of the pressurized gas is characterized in that the return to the female mold is prevented.

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According to the present invention, deformation of the molded article and transfer nonuniformity can be minimized, and the molding time can be shortened. Moreover, also in the molded article which has a thin part, the transfer property can be improved in this thin part.

BEST MODE FOR CARRYING OUT THE INVENTION [

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described based on drawing. First, the whole structure of the injection molding apparatus is demonstrated based on FIG. 1 is a stationary side assembly attached by bolts to a stationary platen (not shown), and the stationary side assembly 1 is a stationary side first base plate 2 and the stationary side first base plate 2. ) Fixed side second base plate 3 fixed by bolts), fixed side second base plate 3 fixed to second fixed base plate 3 by bolts, and this fixed side third A female mold part (fixed mold part) 6 disposed in a recess of the base plate 4 and fixed to the fixed side third base plate 4 by a bolt, and the fixed side first base plate 2. A rocket ring 7 installed around the stationary platen of the rocket ring 7 for positioning the stationary side first base plate 2 with respect to the stationary platen, and a sprue bush disposed adjacent to the rocket ring 7. bush) 8 and the like.

In addition, a sprue 9 for passing molten synthetic resin injected from an injection nozzle (not shown) is formed at the center of the sprue bush 8, and a runner 10 is formed at a lower center portion thereof, and a runner ( A plurality of gates 11, which are the exits of 10, are formed. In addition, 12 is a heat medium passage formed along this cavity S in the site | part near the cavity S of the said female mold part 6, The hot medium which is a heating medium, or cooling water which is a cooling medium in this heat medium passage 12 is used. It flows and the cavity formation surface side of the female mold part 6 is heated or cooled.

On the other hand, 20 is a movable side assembly attached to the movable platen (not shown) by bolts, and the movable side assembly 20 includes the movable side first base plate 21 and the movable side first base plate 21. Bolts on the movable side first base plate 21 (ejector plate) fixed by bolts on the movable side and the movable side first base plate 21 to surround the movable side second base plate 22. Movable side third base plate 23 fixed by the movable side, movable side fourth base plate 24 fixed to the movable side third base plate 23 by bolts, and the movable side fourth base plate ( A mold body 26 fitted into the recess of the mold 24 and fixed to the fourth plate 24 and a generally rectangular parallelepiped shape fitted into the recess of the mold body 26 and fixed to the mold body 26. With male mold (movable mold) 27 The lure is.

Then, a guide rod (not shown) installed upright on the movable side third base plate 23 is inserted into the guide hole formed in the fixed side third base plate 4, and the guide rod is guided to the guide hole and movable. The side assembly 20 is made possible up and down.

Next, in FIG. 2 which is a plan view of the said male mold part 27 of a quadrangular shape in plan view, and FIG. 3 which is AA sectional drawing of FIG. The cavity S, which is formed, for example, into a rectangular cylinder-like space extending from the outer circumferential portion of the space, has an upper lid (a rectangular horizontal plane and each side of the horizontal plane) of an upper surface of the box. (I) having four vertical faces hanging down from (i)), but a molded article having a predetermined width is formed on the back side of the molded article with a rectangular frame-shaped thin section (U). Is formed. The four sides of the thin portion U may all have the same thickness or may not have the same thickness, respectively.

28A and 28B are gas injection paths for supplying pressurized gas (for example, nitrogen gas or air) from a pressurized gas source (not shown) into the cavity S through a supply valve. The discharge path is for discharging the pressurized gas in the cavity S out of the injection molding apparatus through the discharge valve.

As shown in FIG. 6, the butt | matching part of the said mold base 26 and the male mold part 27 is located in the intermediate position of the bottom face of the outer peripheral part of the cavity S which forms the vertical surface of a molded article, The bottom of the outer peripheral portion is formed of a mold body 26 and a male mold portion 27. At the upper end portions of the abutment portions of the mold body 26 and the male mold portion 27, the protrusions 30 and 31 protruding upward at the same height level so as to be grabbed into each other into the cavity S are formed in a planar shape. It is formed in a frame shape (stripes), and the outer part of the upper part of the protrusion part 31 is partially cut off so that the lower part is in contact with the gap without gaps, but the groove 34 is formed in the upper part.

That is, the protruding portion 30 of the mold body 26 raises each side forming a concave portion for fitting the male mold portion 27 of the mold body 26 and then inclines it low as it goes outward. The vertex angle is formed such that, for example, a longitudinal section of about 20 to 45 degrees shows a generally right triangle. In addition, the protruding portion 31 of the male mold portion 27 raises each side of the male mold portion 27 in contact with each side of the mold body 26 forming the concave portion to the same height level as the protruding portion 30. Then, the outer part of the upper part of the protrusion part 31 is excised and then inclined low as it goes to the inner side, and the vertex angle is formed such that a longitudinal section of, for example, about 20 to 45 degrees shows a generally right triangle, and the protrusion parts 30 and 31 are In the upper portion, a groove 34 having a width (for example, a width of 0.5 mm or less) is formed on the upper portion so that the pressurized gas G does not enter.

32 is a recess formed in the upper surface of the male mold part 27 to form ribs protruding downward on the bottom of the molded article, and 33 is similarly formed in the male mold part 27 to form a hollow cylindrical part projecting downward on the bottom of the molded article. It is a recess formed in the upper surface.

Next, in FIG. 7, 35, a continuous shape having a predetermined width on the upper surface of the male mold portion 27 is fitted into the rectangular frame shape (belt shape) to be fixed to the male mold portion 27. Into the first bush, which is a thin thin body, the first bush 35 has an upper portion of the first bushing into the cavity S, and the upper longitudinal section has an isometric trapezoidal shape in which the upper bottom is shorter than the lower bottom. The gap between the top surface 42 and the female mold portion 6 formed over the entire circumference of the upper portion of the first bush 35 is shorter than the other portions, and as described above, the molded article has a predetermined width. The continuous shape is configured to form a rectangular frame-shaped thin strip (U).

In addition, the outer and inner peripheral portions of the upper surface of the first bush 35 protrude protrusions 36 and 37 that are plunged into the cavity S, and the protrusions 36 and 37 have a rectangular frame shape in plan view. ), The outer side and the inner side of the first bushing 35 are raised lower than the top plane 42, and then tilted low as they go inward, so that the vertex angle is, for example, about 20 to 45 degrees. The longitudinal section is formed to have a generally right triangle, and at the same time, tapered portions 38 and 39 are formed at the top thereof. That is, the height level of the intersection portion between the quadrilateral portion forming the protrusions 36 and 37 and the quadrilateral portion of the first bushing 35 having an equilateral trapezoidal shape is the same level as the bottom surface forming the cavity S. The angles formed by the two quadrilateral portions are substantially perpendicular to about 90 degrees, and tapered portions 38 and 39 having good thermal conductivity are formed at the tops of the protrusions 36 and 37.

Next, in FIG. 9, 40 is a 2nd bush which is a substantially rectangular parallelepiped opening formed by fitting in the recessed part of the upper surface of the said male mold part 27, and being fixed to this male mold part 27, and through-hole in a molded article. The upper end abuts on the female mold part 6 in a mold clamping state. In other words, the second bush 40 is provided with a fixing part 40A having a large planar area that fits into the concave part of the upper surface of the male mold part 27, and a cavity S between the fixing part 40A and the fixing part 40A. And a through hole forming portion 40B formed at an upper portion thereof to form a through hole in the molded article and having an upper surface contacting the female mold portion 6. At the outer circumferential end of the upper surface of the bush 40, that is, at the outer circumferential end of the upper surface of the through hole forming portion 40B, each outer surface of the second bush 40 is formed to have a short width protrusion 41 which is pushed into the cavity S. Let it protrude.

In addition, the protrusions 41 are formed so as to form grooves 53 with a slight distance from the protrusions 41 while the second bushes 40 are fitted in the recesses on the upper surface of the male mold portion 27. Protruding portion 44 is installed on the male mold portion 27 upper surface so as to surround from the upper portion. In this case, the protrusion part 41 of the second bush 40 and the protrusion part 44 of the male mold part 27 have the same height level, and the width of the opening formed therebetween is pressurized by the gas G. The depth of the groove 54, which is not wide enough (for example, a width of 0.5 mm or less), is formed slightly shallower than the depth of the cavity S. The protrusions 41 of the second bush 40 and the protrusions 44 of the male mold part 27 are formed in a rectangular frame shape in plan view.

In addition, in FIG. 1 and FIG. 3, 48 is a plurality of outflow entry paths which communicate the clearance of the 1st bush 35 and the male mold part 27, and the compression tank 47, 49 is the 2nd bush 40 ) And an outflow entry path 49 communicating the gap between the male mold part 27 and the compression tank 47, the compression tank 47 is an injection molding apparatus through the discharge path 50 in which the discharge valve is disposed. It is connected outside.

With the above configuration, at the time of injection molding, hot steam, which is a heat medium, is first supplied into the heat medium passage 12 of the female mold part 6, and the cavity forming surface side of the female mold part 6 is heated, and this cavity S The temperature rise is started so as to be a predetermined temperature within the range of 80 ~ 200 ℃ according to the type of synthetic resin to be injected into the), and the fixed side assembly 1 and the movable side assembly 20 is mold clamped (see Fig. 3). As described above, the temperature is not limited to the case of mold clamping after starting the temperature raising, and the temperature rising may be started after mold clamping at the same time as the temperature raising or the mold clamping.

When the cavity forming surface side of the female mold part 6 reaches the above-mentioned predetermined temperature, the supply of steam is stopped to stop the temperature increase, and the injection nozzle is sputtered through the sprue bush 8 to melt the synthetic resin J. Through the hole 9, the mold is injected into the cavity S between the male mold part 27 and the female mold part 6. In this case, molten synthetic resin J of about 80% by volume to about 98% by volume of the space S of the cavity S is injected, for example, about 90% by volume (see Fig. 4).

When the injection of the molten synthetic resin (J) of about 90% by volume is finished, pressurized gas (G) of about 10% by volume of the space volume of the cavity (S) is supplied from the pressurized gas source to the supply valve and the gas injection path ( It supplies in cavity S through 28A and 28B. The pressurized gas G is injected between the molten synthetic resin J back surface and the cavity forming surface of the male mold portion 27, thereby allowing the molten synthetic resin J to surface the molten synthetic resin J. It presses to the cavity formation surface of and pressurizes it (refer FIG. 5). As a result, the occurrence of shrinkage on the surface of the molded article is suppressed, the transferability is improved, and the problem of appearance defect is solved as much as possible.

Then, when the pressurized gas G is injected, that is, immediately before or after the injection or at the same time as the injection, the supply of cooling water is started in the heat medium passage 12 of the female mold part 6, thereby producing the synthetic resin J. The cavity formation surface side of the female mold part 6 of this is hardened. When the pressure of the pressurized gas G is applied, the surface of the synthetic resin J is cooled to harden the synthetic resin J to a certain extent, for example, as a mold. , The pressurized gas G in the cavity S is discharged out of the injection molding apparatus. When the pressurized gas is discharged out of the injection molding apparatus, cold air is injected through the gas injection passages 28A and 28B between the back surface of the synthetic resin and the cavity forming surface of the male mold portion 27 instead. That is, the synthetic resin back surface (cavity forming surface side of the male mold portion 27) is slightly lower than the cooling of the synthetic resin surface (cavity forming surface side of the female mold portion 6) and at a temperature equal to or slightly lower than the cooling temperature. Cool.

Therefore, when the back surface of the synthetic resin is not cooled, warpage may occur in the molded article due to a difference in shrinkage ratio due to the temperature difference between the front side and the back side, but the molding time can be shortened by the cooling and at the same time The problem of warpage can be solved. In addition, cooling the back surface temperature of the synthetic resin (J) slightly below the surface temperature is to prevent deformation by the ejector pin at the time of mold release of the molded article, and cooling to the same temperature is to prevent deformation by the ejector pin. If there is no problem, to shorten the molding time.

Then, if the synthetic resin is solid enough to be taken out from the cavity S, the injection of cold air into the cavity S and the supply of the cooling water into the heat medium passage 12 of the female mold part 6 are stopped. The mol clamping is opened, the molded article by the ejector pin is released, and ready for production of the next molded article as described above.

In addition, the cavity forming surface of the female mold part 6 is injected between the synthetic resin J in which the pressurized gas G is melted and the molten synthetic resin J injected between the cavity forming surface of the male mold part 27. It is necessary to spread the melted synthetic resin (J) to all corners of the cavity (S) at the time of pressurizing and pressurizing to spread it so that the density of the molten synthetic resin (J) is uniform everywhere. have. Thus, specific embodiments therefor will be described below.

First, the shaping | molding operation | movement in the bottom face of the outer peripheral part of the cavity S which is a place where melted synthetic resin J is hard to reach at the same density is demonstrated based on FIG. That is, the bottom surface of the outer peripheral portion of the cavity S is formed of the mold base 26 and the male mold portion 27, and the butt portion of the mold base 26 and the male mold portion 27 forms a vertical surface of the molded article. Since it is located in the intermediate position of the bottom face of the outer peripheral part of (S), when a certain amount of pressurized gas G is injected into the cavity S through the gas injection paths 28A and 28B, it will be shown in FIG. Although it is in a state, when it is injected further, the molten synthetic resin J proceeds toward the butt portion of the mold base 26 and the male mold portion 27, which are end portions of the cavity S.

In this case, the surface of the molten synthetic resin J is hardened slightly with movement, but the synthetic resin J at the tip touches the protrusions 30 and 31 of the mold body 26 and the male mold part 27 ( (B) of FIG. 6, synthetic resin J sticks in a part of groove 34 which has a width | variety (for example, the width of 0.5 mm or less) that the pressurized gas G does not collect. At the same time, the hard surface of this synthetic resin (J) is broken and soft parts appear outward. Then, the molten synthetic resin J spreads to the butt part of the mold base 26 and the male mold part 27 which are terminal parts of the cavity S. As shown in FIG. That is, since the soft molten synthetic resin (J) that appears outwardly enters all of the grooves 34, the pressurized gas returns to the female mold part 6, or the female mold part 6 and the mold body 26 Leakage from the gap to the outside of the injection molding apparatus can be prevented, and the surface of the synthetic resin can be pushed to the cavity forming surface of the female mold part 6 by pressurized gas to sufficiently pressurize it (see Fig. 6C).

Moreover, although the rib 34 produces a thin rib in the molded article, since the rib does not protrude outward from the molded article outer shape, there is no problem in appearance and function as the molded article.

Next, the shaping | molding operation around the 1st bush 35 which is a place where molten synthetic resin J is hard to reach at the same density is demonstrated based on FIG. 7 and FIG. First, when the pressurized gas G is injected into the cavity S through the gas injection paths 28A and 28B so as to press the surface of the molten synthetic resin J to the cavity forming surface of the female mold part 6 and pressurize it, As shown in FIG. 8A, the pressurized gas G contacts the side surfaces of the protrusions 36 and 37 of the first bush 35.

In addition, when pressurized gas G is injected, it rises and touches the taper parts 38 and 39 of this protrusion part 36 and 37 (refer FIG. 8 (B)), and this taper parts 38 and 39 are carried out. 8 (see FIG. 8C) and to the lower bottom of the inclined portions of the protrusions 36 and 37 to partially reach the quadrilateral of the first bushing 35 (see FIG. 8E), yet The part which does not reach to the quadrilateral part of the 1st bush 35 also arises (refer FIG. 8 (D)). In this case, the taper portions 38 and 39 are thermally stored by the heat of the molten synthetic resin J.

Finally, the synthetic resin J is softened by the heat storage tapered portions 38 and 39, and the pressurized gas G extends over the protrusions 36 and 37 and the quadrilateral portions and the first portions of the protrusions 36 and 37. By moving along the ridges formed at the quadrilateral portions of the bushes 35, the pressurized gas G reaches the entire ridges (see FIG. 8F). Therefore, since the angle formed between the quadrilateral portions of the protrusions 36 and 37 and the quadrilateral portions of the first bushes 35 is approximately right angles, the quadrilateral of the first bushing 35 reaches this solid portion. The synthetic resin (J) is pushed up along the portion, and the synthetic resin (J) has the same density even in a short (narrow) portion of the gap between the top plane 42 of the first bushing 35 and the female mold portion 6. It can fully pressurize in the state which spread widely (in FIG. 7, the pressurization direction is shown by the arrow), and even if the thin part U is formed in a molded article, transfer unevenness and deformation | transformation can be prevented.

In this case, the male mold portion 27 and the first bush 35 are not pressurized to the portion where the synthetic resin J can be pressurized with the pressurized gas G on the cavity-forming side of the female mold portion 6. Through a small gap with) and the outflow entry path 48, the pressurized gas G in the cavity S is collected in the compression tank 47. On the other hand, the pressurized gas collected in the compression tank 47 is supplied into the cavity S through the gap and the outflow entry and exit path 48 so as to spread widely even in a portion that is not sufficiently pressurized. As a result, the pressurized gas does not competitively rise along the quadrilateral portion of the first bushing 35, and has a uniform density over the entire circumference of the thin portion U of the molded article, so that the molded article can be molded in the shape of a mold. do.

Next, pressurized gas is injected into the cavity S through the gas injection passages 28A and 28B so as to push the surface of the synthetic resin J to the cavity forming surface of the female mold part 6 and pressurize it to form a through hole in the molded article. Also in the case of forming the above, it can be surely coped, but this will be described based on FIG. 9.

That is, as shown in FIG. 9, the molten synthetic resin J injected into the cavity S passes beyond the protrusion 44 on the upper surface of the male mold part 27 by the pressurized gas and the protrusion 41 and the protrusion. Into the groove 54 formed of the 44, the further progresses to reach the through hole forming portion 40B of the second bush 40 and the groove 53 formed of the protruding portion 41.

In this case, the male mold portion 27 and the second bush 40 are not pressurized to the portion where the synthetic resin J can be pressurized with the pressurized gas G on the cavity-forming side of the female mold portion 6. The pressurized gas G in the cavity S is collected in the compression tank 47 through a small gap with the) and the outflow entry path 49. On the other hand, the pressurized gas collected in the compression tank 47 is supplied into the cavity S through the gap and the outflow entry and exit path 48 so as to spread widely even in a portion that is not sufficiently pressurized.

In this way, the flow of the pressurized gas G is temporarily stopped by the action of the compression tank 47 or by letting the grooves 53 and 54 enter the synthetic resin so that the pressurized gas G is extended to other parts. By pressurizing and increasing the volume of the pressurized gas G in the cavity S, it can pressurize and can raise the density of the synthetic resin around the through-hole (opening part) of a molded article. Then, the pressure around the through hole (opening) is increased to increase the pressure, and the temperature of the synthetic resin decreases due to the male mold portion 27 whose temperature is lowered. Therefore, it is possible to prevent the pressurized gas G from being pulled up along the side surface of the through-hole forming portion 40B of the second bush 40 at the same time as the synthetic resin is cured and returned to the female mold portion 6.

In addition, as described above with reference to FIG. 6, the bottom surface of the outer peripheral portion of the cavity S is formed of the mold body 26 and the male mold part 27, and the mold body 26 and the male mold part 27 are formed. When the protrusions 30 and 31 protrude upwards in the cavity S from each other, the upper portions of the upper portions of the protrusions 31 are cut off to face the protrusions 30 and 31 so that the lower portions are in contact with each other without any gaps. Although 34) is formed so that it may be formed, it is not limited to this, You may set it as another embodiment of the structure shown in FIGS.

That is, as shown in FIG. 10, the upper surface of the mold body 26 around the male mold part 27 has a vertical angle of about 20 to 45 degrees, with a vertex angle projecting upward in the cavity S, for example, at a right angle. Protruding portion 30A having a triangular shape is formed, that is, each side of the mold body 26 which is in contact with each side of the male mold portion 27 is raised, and then inclined low as it goes outward so that the longitudinal section is generally right angled. 30 A of protrusions are formed so that it may show a triangle, and the outer part of the male mold part 27 is partly cut | disconnected by forming the step part 27A from the same height level as the bottom face of the cavity S, and with the said protrusion part 30A. A groove 34A having a width (for example, a width of 0.5 mm or less) is formed so that the pressurized gas G constituting a part of the cavity S does not enter. In addition, the protrusions 30A and 31A are formed in a rectangular frame shape in a plan view.

Therefore, since the molten synthetic resin J enters into the groove 34A, the pressurized gas can be prevented from returning to the female mold part 6, and at the same time, the mold gas 26 and the female mold part 6 Outflow from the gap can be prevented, and the surface of the synthetic resin can be pushed to the cavity forming surface of the female mold part 6 by pressurized gas to sufficiently hold the synthetic resin J to harden within the pressurized time. Can be.

As shown in Fig. 11, a longitudinal section projecting upward in the cavity S forms a rectangular projection 30B around the male mold portion 27 of the mold body 26, i.e., the male mold portion ( Raise each side of the mold body 26 in contact with each side of 27) to form a projection 30B having a rectangular cross section, and the outer side of the male mold portion 27 from the same height level as the bottom of the cavity S. A portion of the cavity (to form a step portion 27A) and a width (for example, 0.5 mm or less) at which the pressurized gas G, which forms part of the cavity S, does not enter between the protrusions 30B. Groove 34B having a width of? In addition, the protrusion 30B is formed in a rectangular frame shape (stripe shape) in plan view.

Therefore, since the molten synthetic resin J enters into the groove 34B, the pressurized gas can be prevented from returning to the female mold part 6, and at the same time, the mold gas 26 and the female mold part 6 Outflow from the gap can be prevented, and the surface of the synthetic resin J can be pushed to the cavity forming surface of the female mold part 6 by pressurized gas, so that the pressure can be sufficiently held, and the synthetic resin J melted within the pressurized time. Can be cured.

In addition, as shown in FIG. 12, the vertical section projecting upwardly in the cavity S has a generally rectangular shape around the male mold portion 27 of the mold body 26, and has a rectangular shape farther than the male mold portion 27. The protruding portion 30C is formed to form a protruding portion 30C by forming a rounded protruding portion 30C, that is, protruding each side of the mold body 26 in contact with each side of the male mold portion 27. A part of the outer portion of the male mold portion 27 is cut off from the same height level as the bottom surface (to form a step portion 27A), and the pressurized gas G forming a part of the cavity S between the protrusion portion 30C is held. The groove 34C having a width (for example, a width of 0.5 mm or less) of the extent not to be formed is formed. In addition, the projection 30C is formed in a rectangular frame shape (stripe shape) in plan view.

Therefore, since the molten synthetic resin J enters into the groove 34C, the pressurized gas can be prevented from returning to the female mold part 6, and at the same time, the mold gas 26 and the female mold part 6 Outflow from the gap can be prevented, and the surface of the synthetic resin J can be pushed to the cavity forming surface of the female mold part 6 by pressurized gas, so that the pressure can be sufficiently held, and the synthetic resin J melted within the pressurized time. Can be cured.

In the case of the molded article SJ shown in FIG. 28, that is, the horizontal surface X and the continuous vertical surface Z1 communicating vertically from the outer peripheral portion of the horizontal surface X are provided. In the molded product SJ having a continuous cylindrical or square cylindrical surface Z2 communicating in the vertical direction with the horizontal surface X on the lower surface, or without the vertical surface Z1, the horizontal surface X and the vertical surface Z2 Also in the case of molding a molded article provided with the above, technical ideas such as those shown in Figs. 6 and 10 to 12 can be applied naturally. That is, not only the cavity formed by the space extending in a horizontal direction and the tubular space extended in the vertical direction communicating with the outer periphery of this space, but the space extending in the horizontal direction and the cylinder extending in the vertical direction communicating with this space If the cavity is formed into a shaped space, the above technical concept can be applied to a cavity having a tubular space extending in the vertical direction in communication at an intermediate position not reaching the outer peripheral portion of the space extending in the horizontal direction.

Moreover, when forming the thin part U in a molded article, as shown to FIG. 7 and FIG. 8, this male mold is fit in the recessed part formed in the upper surface of the male mold part 27. Although it fixed to the part 27, it is not limited to this, It may be comprised by the unitary structure shown in FIG. 13, without dividing in this way, and the thin-mold part is formed in the male mold part 27 instead of the 1st bush 35. FIG. You may form 35A.

Hereinafter, based on FIG. 13 and FIG. 14, embodiment which forms the said thin formation part 35A in the male mold part 27 is described. Initially, 35A is a thin-film forming portion formed continuously on the upper surface of the male mold portion 27, and the longitudinal section of the thin-film forming portion 35A has an equilateral trapezoidal shape whose upper bottom is shorter than the lower bottom. The gap between the top plane 42A and the female mold part 6 formed over the entire circumference of the upper part of the top) is shorter than the other parts, so that the thin part U can be formed in the molded article.

In addition, protrusions 36A and 37A projected into the cavity S are projected to the outer peripheral portion and the inner peripheral portion of the thin-film forming portion 35A, and the protrusions 36A and 37A are rectangular in the form of a frame (band shape) in plan view. It is formed to be lower than the top plane 42A, and then inclined low as it goes inwardly, so that the vertex angle, for example, about 20 to 45 degrees is formed such that the longitudinal section is generally a right triangle. Tapered portions 38A and 39A are formed at the top. That is, the height level of the intersection portion of the quadrilateral portion forming the protrusions 36A and 37A and the quadrilateral portion of the thin-shaped forming portion 35A of the conformal trapezoidal shape is the same height level as the bottom surface forming the cavity S, The angles formed by both quadrilaterals are approximately right angles, and tapered portions 38A and 39A having good thermal conductivity are formed at the tops of the protrusions 36A and 37A.

Then, when the pressurized gas G is injected into the cavity S through the gas injection paths 28A and 28B so as to press the surface of the molten synthetic resin J to the cavity forming surface of the female mold part 6 and pressurize it, As shown to FIG. 14 (A), pressurized gas G is contacted so that it may abut on the side surface of the projection part 36A, 37A of the thin film formation part 35A.

Moreover, when pressurized gas G is injected, it raises and touches the taper parts 38A and 39A of these protrusion parts 36A and 37A (refer FIG. 14 (B)), and this taper parts 38A and 39A Over (see FIG. 14C) and to the lower bottom of the inclined portions of the projections 36A and 37A to partially touch the quadrilateral of the thin-walled portion 35A (see FIG. 14E), or The part which does not reach to the quadrilateral part of the thin formation part 35A also arises (refer FIG. 14 (D)). In this case, the taper portions 38A and 39A are thermally stored by the heat of the molten synthetic resin J.

Then, the synthetic resin J is softened by the tapered portions 38A and 39A finally stored, and the pressurized gas G exceeds the protrusions 36A and 37A so that the pressurized gas G is formed in the protrusions 36A and 37A. By moving along the solid ridge formed by the quadrilateral portion of the quadrilateral portion and the thin-film forming portion 35A, the pressurized gas G comes in contact with the entire solid portion (see FIG. 14F).

Therefore, since the angle which the pressurized gas G which reached | attained to this fixed part forms the quadrangle | corner of the quadrilateral parts of the projection parts 36A and 37A and the quadrangle part of the thin film formation part 35A is approximately orthogonal, the quadrangle part of the thin film formation part 35A is Therefore, the synthetic resin J is pressed to push up the molten synthetic resin J, and the molten synthetic resin J is also melted in the short (narrow) portion of the gap between the top plane 42A of the thin-walled part 35A and the female mold part 6. The pressure can be sufficiently pressed in a widely spread state (in Fig. 13, the pressing direction is indicated by an arrow), and the continuous outer shape having a predetermined width on the back side of the molded article has a rectangular frame-shaped thin strip (U). Also in the case of forming the transfer non-uniformity or deformation can be prevented. The four sides of the thin portion U may all have the same thickness or may not be the same thickness, respectively.

Moreover, when forming the thin part U in a molded article, as shown to FIG. 7 and FIG. 8, this male mold is fit in the recessed part formed in the upper surface of the male mold part 27. Although it fixed to the part 27, similarly to this, as shown in FIG. 15, the 1st bushing 35B fits in the recessed part formed in the upper surface of the male mold part 27, and is attached to this male mold part 27. FIG. It may be fixed, and will be described below.

That is, in FIG. 15, 35B shows that a continuous shape having a predetermined width on the upper surface of the male mold part 27 is fitted in the recess of the rectangular frame shape (belt shape) to be fixed to the male mold part 27. In FIG. As the first bush, the first bush 35B has an isometric trapezoidal shape in which the upper longitudinal section is shorter than the lower bottom in the upper end section, and the top plane 42B formed over the entire circumference of the upper part of the first bush 35B. ) And the female mold part 6 is shorter than the other parts, and is configured such that a continuous outer shape having a predetermined width on the back side of the molded article can form a rectangular frame-shaped thin band U. . The four sides of the thin portion U may all have the same thickness or may not be the same thickness, respectively.

In addition, the lower height level of the quadrilateral portion of the first bushing 35B having an upper trapezoidal shape is at a position higher than the height level of the bottom surface of the cavity S, and is located outside the outer periphery of the first bushing 35B. In the upper part of the male mold part 27 which is inner side of the inner circumference, the longitudinal cross section which is squeezed into the cavity S has a trapezoidal shape in which the upper bottom is shorter than the lower bottom (if it is extended, the vertex angle is about 20 to 45 degrees, for example). Longitudinal cross-section generally shows a right triangle.) The protrusions 55 and 56 have a width (for example, a width of 0.5 mm or less) that the pressurized gas G does not enter the first bushing 35B. It protrudes at intervals (grooves 59A and 59B). That is, the protrusions 55 and 56 are formed on the upper surface of the male mold 27 positioned near the first bush 35B.

Further, the projections 57 and 58 are formed at a slight distance from the projections 51 and 56 formed in a rectangular frame shape (stripe shape) in plan view. The projections 57 and 58, which are plunged into the cavity S, are formed in a rectangular frame shape (stripe shape) in plan view, and the vertical angle of the vertex angle of about 20 to 45 degrees is a right triangle shape, and upwards. After raising it vertically, it inclines low as it goes to the direction of the 1st bush 35B, and the angle | corner of the quadrilateral part of this protrusion part 57 and 58 and the quadrangle part of the protrusion part 55 and 56 is almost right angled. to be. In addition, bottom surfaces of the grooves 59A and 59B formed between the protrusions 55 and 56 and the first bush 35B are at a level level higher than that of the cavity S bottom surface.

Then, when pressurized gas is injected into the cavity S through the gas injection passages 28A and 28B to pressurize and press the surface of the molten synthetic resin J to the cavity forming surface of the female mold part 6, it is pressurized first. The gas abuts against the vertical sides of the protrusions 57, 58. In addition, when the pressurized gas is injected, it rises and touches the upper ends of the protrusions 57 and 58, and eventually reaches the upper ends of the protrusions and the lower edges of the quadrilateral portions of the protrusions 55 and 56, further causing the quadrilaterals of the protrusions 55 and 56. Reach the part.

At this time, the pressurized gas that has reached the quadrilateral portions of the protrusions 55 and 56 has an angle between the quadrilateral portions of the protrusions 55 and 56 and the quadrilateral portions of the protrusions 57 and 58 at right angles, so that the protrusions 55 56 to move in a direction orthogonal to the quadrilateral portion and a direction orthogonal to the quadrangle portion of the protrusions 57 and 58 (see arrows in FIG. 15), and consequently Pressed to push up the molten synthetic resin (J) along the quadrilateral portion of one bush (35B), and the short (narrow) portion of the gap between the top surface 42B and the female mold portion 6 of the first bush 35B. Also, the melted synthetic resin J can be sufficiently pressurized in a widely spread state, so that even when a thin portion is formed in a molded article, transfer unevenness or deformation can be prevented.

In addition, as mentioned above, when forming a thin part in a molded article, the first bush 35 as a thin formed body, the thin formed part 35A formed in the male mold part 27, and the 1st as a thin formed body. Using the bush 35B, a continuous outline having a predetermined width is formed on the back side of the molded article so as to form a rectangular frame-shaped thin band, but not limited to such a shape, but continuous in a frame It may be H-shaped not having a cross shape or other shape. Moreover, all the thin parts formed in this molded article may be the same thickness, and may be different thickness for every straight line, respectively.

Moreover, not only the shape of the protrusion part 41 of the 2nd bush 40 shown in FIG. 9, but the shape of the protrusion part 44 formed in the male mold part 27, implementation of the shape shown in FIGS. 16-18. It may be in the form.

First, as shown in FIG. 16, each side surface is raised in the outer peripheral part of the upper surface of the fixing part 40A of the 2nd bush 40, and is inclined low as it approaches the through-hole formation part 40B, and then cavity C ), The corner angle of the projection into the projections protrudes, for example, a projection 41A having a generally right triangle shape having a longitudinal section of about 20 to 45 degrees, and a groove 53A between the through hole forming portion 40B and the projection 41A. Is formed. And 44A of protrusions formed so that this protrusion 41A may be enclosed from the outside may be made low as each side of the male mold part 27 which forms the recessed part which the 2nd bush 40 fits up raises, and goes outward. The inclined angle is formed such that the longitudinal section of, for example, about 20 to 45 degrees shows a substantially right triangle.

Then, at the upper end portions of the butt portions of the fixing portion 40A and the male mold portion 27 of the second bush 40, the protrusions 41A protruding upward at the same height level so as to be pushed into each other into the cavity S, and The protrusions 44A are formed in a rectangular frame shape in a plan view, and the outer portions of the upper portions of the protrusions 44A are partially cut to fix the fixing portions 40A and the male mold portions 27 of the second bush 40. But the lower part is in contact with a gap, but the groove 54A is formed in the upper part which has a width | variety (for example, the width of 0.5 mm or less) that the pressurized gas G does not enter. In this case, the depth of the groove 54A formed by the protruding portion 41A of the second bush 40 and the protruding portion 44A of the male mold portion 27 is slightly shallower than the depth of the cavity S.

Then, the pressurized gas is injected into the cavity S through the gas injection passages 28A and 28B, and the molten synthetic resin J melts when the through-hole is formed in the molded article. It is formed in the groove 54A formed by the protrusion 44A and the protrusion 41A above the protrusion 44A on the upper surface, or formed by the through hole forming portion 40B and the protrusion 41A of the second bush 40. It reaches into the groove 53A.

In this case, the male mold portion 27 and the second bush 40 are not pressurized to the portion where the synthetic resin J can be pressurized with the pressurized gas G on the cavity-forming side of the female mold portion 6. The pressurized gas G in the cavity S is collected in the compression tank 47 through a small gap with the) and the outflow entry path 49. On the other hand, the pressurized gas collected in the compression tank 47 is supplied into the cavity S through the gap and the outflow entry and exit path 49 so as to spread widely even in a portion that is not sufficiently pressurized.

In this way, the flow of the pressurized gas G is temporarily stopped by the action of the compression tank 47 or by letting the synthetic resin into the grooves 53A and 54A so that the pressurized gas G is extended to other parts. By pressurizing and increasing the volume of the pressurized gas G in the cavity S, it can pressurize and can raise the density of the synthetic resin around the through-hole (opening part) of a molded article. Then, the pressure around the through hole (opening) is increased to increase the pressure, and the temperature of the synthetic resin is lowered by the male mold portion 27 whose temperature is lowered. Therefore, it is possible to prevent the pressurized gas G from being pulled up along the side surface of the through hole forming portion 40B of the second bush 40 and returning to the female mold portion 6 while the synthetic resin is cured.

Moreover, as shown in FIG. 17, each side surface is raised in the outer peripheral part of the upper surface of the fixing part 40A of the 2nd bush 40, and it lowers as it approaches the through-hole formation part 40B, and then lowers the cavity S A longitudinal cross section which is plunged into the protrusion projects an arc-shaped protrusion 41B, and a groove 53B is formed between the through-hole forming portion 40B and the protrusion 41B. The protrusion 44B formed so as to surround the protrusion 41B from the outside raises up each side surface of the male mold portion 27 that forms the recess to which the second bush 40 fits, and then moves outward. It is made low, and the longitudinal cross section is formed so that it may show circular arc shape.

Then, at the upper end portions of the butt portions of the fixing portion 40A and the male mold portion 27 of the second bush 40, the protrusions 41B protruding upward at the same height level so as to fit into each other into the cavity S, and The protrusions 44B are formed in a rectangular frame shape in a plan view, and the outer portions of the upper portions of the protrusions 44B are partially cut to fix the fixing portions 40A and the male mold portions 27 of the second bush 40. While the lower surface is in contact with the gap without gaps, the groove 54B having a width (for example, a width under 0.5 mmEL) is formed in the upper portion so that the pressurized gas G does not enter. In this case, the depth of the groove 54B formed by the protrusion 41B of the second bush 40 and the protrusion 44B of the male mold part 27 is slightly shallower than the depth of the cavity S.

Then, the pressurized gas is injected into the cavity S through the gas injection passages 28A and 28B, and the molten synthetic resin J melts when the through-hole is formed in the molded article. It is formed in the groove 54B formed by the protrusion 44B and the protrusion 41B beyond the protrusion 44B on the upper surface, or formed by the through-hole forming portion 40B and the protrusion 41B of the second bush 40. It reaches into the groove 53B.

In this case, the male mold portion 27 and the second bush 40 are not pressurized to the portion where the synthetic resin J can be pressurized with the pressurized gas G on the cavity-forming side of the female mold portion 6. Through a small gap with the) and the outflow entry path 49, the pressurized gas G in the cavity S is collected in the compression tank 47. On the other hand, the pressurized gas collected in the compression tank 47 is supplied into the cavity S through the gap and the outflow entry and exit path 49 so as to spread widely even in a portion that is not sufficiently pressurized.

In this way, the flow of the pressurized gas G is temporarily stopped by the action of the compression tank 47 or by letting the synthetic resin into the grooves 53B and 54B so that the pressurized gas G is extended to other parts. By pressurizing and increasing the volume of the pressurized gas G in the cavity S, it can pressurize and can raise the density of the synthetic resin around the through-hole (opening part) of a molded article. Then, the pressure around the through hole (opening) is increased to increase the pressure, and the temperature of the synthetic resin is lowered by the male mold portion 27 whose temperature is lowered. Therefore, it is possible to prevent the pressurized gas G from being pulled up along the side surface of the through-hole forming portion 40B of the second bush 40 at the same time as the synthetic resin is cured and returning to the female mold portion 6.

In addition, as shown in FIG. 18, each side surface is raised in the outer peripheral part of the upper surface of the fixing part 40A of the 2nd bush 40, and is inclined low as it approaches the through-hole formation part 40B, and then cavity C is shown. ) The angle of the corners that enters into the) is projected by a projection 41C having a generally right triangle shape with a vertical cross-section of about 20 to 45 degrees, for example, a rectangular frame shape (stripes) in view of the through-hole forming portion 40B and in plan view. A groove 53C is formed between the protruding portion 41C.

Then, the pressurized gas is injected into the cavity S through the gas injection passages 28A and 28B, and the molten synthetic resin J melts when the through-hole is formed in the molded article. It is abutted against the protruding portion 41C of the female mold 6 to prevent the return to the female mold portion 6.

That is, especially when the second bush 40, which is a through hole forming body, and the gas injection passages 28A and 28B are far apart from each other, the volume of the pressurized gas G in the cavity S increases to increase the density of the synthetic resin J. If it becomes high and it can pressurize to the circumference | surroundings of the 2nd bush 40, it is not necessary to form a protrusion in the male mold part 27, and it returns to the female mold part 6 only by the protrusion part 41C of the 2nd bush 40. It can prevent entering.

However, as described above, the male mold portion 27 and the first mold are formed so as not to pressurize the synthetic resin J with the pressurized gas G on the cavity-forming side of the female mold portion 6 more than necessary. Through a small gap with the two bushes 40, the pressurized gas G in the cavity S is collected in the compression tank 47, while the pressurized gas collected in the compression tank 47 is sufficiently pressurized. It is necessary to feed into the cavity S through the gap so as to spread widely even in the part not present.

Further, in the above embodiment, the cavity S is an example of molding a molded article having the same shape as the upper lid of the box (having a rectangular horizontal plane and four vertical planes falling down from each side of the horizontal plane). Next, an embodiment in the case of forming a flat molded article will be described based on FIGS. 19 to 22.

First, a generally rectangular parallelepiped bush 65 is fitted into a recess formed in the male mold part 27, and the bush 65 is fixed to the male mold part 27 to fix the cavity S to the female mold part ( 6) and bush 65 and male mold 27. The upper surface of the bush 65 is slightly smaller than the bottom surface of the cavity S, that is, the recess opening periphery of the upper surface of the male mold part 27 and the bottom surface of the cavity S are formed by the bush 65. Form. In addition, a vertical angle of about 20 to 45 degrees, for example, a vertical angle of about 20 to 45 degrees is obtained by raising each side to the outer periphery of the upper surface of the bush 65 and inclining it low as it gets closer to the inside. While showing a triangular shape and protruding the protrusions 60 formed in a rectangular frame shape (stripes) in plan view, pressurized gas G is squeezed in between the female mold part 6 and the protrusions 60. The groove 61 is formed to have a width that does not go (for example, a width of 0.5 mm or less).

In addition, the protrusion 60 is formed over the entire outer peripheral portion of the upper surface of the bush 65 as described above, or the groove 61 is formed in the entirety between the protrusion 60 and the female mold portion 6. It is not necessary to form a part of the outer periphery of the horizontal portion of the molded article which is easily touched by pressurized gas, so as to prevent it from returning to the female mold part 6 surface. In other words, the pressurized gas may be formed in a portion (area) that may leak to the outside of the injection molding apparatus by returning to the female mold part 6 surface.

Then, after a predetermined amount of molten synthetic resin J is injected into the cavity S (see FIG. 20), the pressurized gas from the pressurized gas source is supplied to the cavity S through the supply valve and the gas injection passage 28C. ), A pressurized gas layer is formed between the molten synthetic resin J and the bush 65 injected into the cavity S (see Fig. 21).

In addition, when the pressurized gas is injected, the molten synthetic resin J reaches the periphery of the cavity S, and falls into the groove 61 beyond the quadrilateral portion of the protruding portion 60. Therefore, the molten synthetic resin J which has been plunged into the groove 61 is prevented from moving to the outside of the pressurized gas and prevented from returning to the female mold part 6 surface (see Fig. 22).

In this case, the male mold portion 27 and the bush 65 may be pressed so as not to pressurize the synthetic resin J with the pressurized gas G to the cavity forming side of the female mold portion 6 more than necessary. Through some gaps and the inflow and outflow path 67, the pressurized gas G in the cavity S collects in the compression tank 47. As shown in FIG. On the other hand, the pressurized gas collected in the compression tank 47 is supplied into the cavity S through the gap and the inflow and outflow path 67 so as to spread widely even in a portion that is not sufficiently pressurized. This also prevents pressurized gas from returning to the female mold part 6 and leaking out of the gap between the female mold part 6 and the male mold part 27 to the outside of the injection molding apparatus. The surface of can be pushed to the cavity forming surface of the female mold part 6, and it can fully pressurize.

In addition, the above embodiment is a case of molding a flat molded article, and protrudes the projection 60 to be plunged into the cavity S to the outer peripheral portion of the upper surface of the bush 65, and the female mold portion 6 and the projection ( The grooves 61 are formed between 60, but the cavity S exhibits the same shape as the upper cover of the box (having a rectangular horizontal plane and four vertical planes hanging down from each side of the horizontal plane). EMBODIMENT OF THE INVENTION Embodiment which can prevent the leakage of pressurized gas in the case of shape | molding a molded article is demonstrated based on FIGS. 23-26.

First, a generally rectangular rectangular bush 66 is fitted into a recess formed in the male mold part 27, and the bush 66 is fixed to the male mold part 27 to fix the cavity S to the female mold part ( 6) and the bush 66 and the male mold portion 27, the bottom surface of the cavity (S) is formed by the bush 66 and the male mold portion (27).

Specifically, the apex angle of the bush 66 is slightly raised from the outer circumferential end of the upper surface of the bush 66, and then inclined low as it approaches the inner side thereof, and then the angle of inclination into the cavity S is about 20 to 45 degrees, for example. The protrusions 62 protrude so that the longitudinal cross-section represents a generally right triangle. Moreover, each side surface which forms a recess is raised also in the periphery of the upper surface opening of the male mold part 27 which forms the recessed part of the male mold part 27, and is inclined low as it nears the outer side, and it inclines into the cavity S, The projecting portion 63 protrudes such that its vertex angle is, for example, about 20 to 45 degrees of longitudinal section having a generally right triangle shape. In this case, the protruding portion 63 is formed higher than the protruding portion 62, and pressurized gas G is formed between the protruding portion 62 of the bush 66 and the protruding portion 63 of the male mold portion 27. The groove 64 is formed to have a width (for example, a width of 0.5 mm or less) that does not fit. In addition, although the protrusions 62 and 63 are formed continuously in a rectangular frame shape (stripe shape) in plan view, it is not limited to this, It does not need to be continuous, and pressurized gas is made to the male mold part 27 surface. What is necessary is just to form in the part (region) which may return and leak to the exterior of an injection molding apparatus.

First, when a predetermined amount of molten synthetic resin J is injected into the cavity S, some of the molten synthetic resin J is injected into the groove 64 beyond the quadrilateral portion of the protrusion 63 (see FIG. 24), and then from the pressurized gas source. Is supplied to the cavity S through the supply valve and the gas injection passage 28D, a pressurized gas layer is formed between the molten synthetic resin J and the bush 66 injected into the cavity S ( 25).

In addition, when the pressurized gas is injected, the pressurized gas reaches the upper portion of the protrusion 62 of the bush 66, but the protrusion 63 of the male mold portion 27 is larger than the protrusion 62 of the bush 66. Is formed at a high level position, the pressurized gas can be pressurized without exceeding the protruding portion 63 (see FIGS. 26 and 27).

That is, as described above, since the protrusion 63 of the male mold portion 27 is formed at a higher level position than the protrusion 62 of the bush 66, the synthetic resin J melted by pressurized gas is held in pressure. Even if the molten synthetic resin (J) that is not squeezed into the groove 64 and the molten synthetic resin (J) that is not squeezed is not cut. For this reason, when cut | disconnected, pressurized gas may return to the male mold part 27 surface beyond both protrusion parts 62 and 63, and may leak to the exterior of an injection molding apparatus, but this return can be prevented and sufficient pressure retention is carried out. It is possible to cure the synthetic resin (J) melted in the time to be pressed.

As mentioned above, although embodiment of this invention was described, various alternative examples, correction, or a deformation | transformation are possible for a person skilled in the art based on the above-mentioned description, and this invention is various in the range which does not deviate from the meaning. It includes alternatives, modifications or variations of the branches.

1 is a vertical front view of an injection molding apparatus.

2 is a plan view of the male mold part.

3 is a cross-sectional view taken along the line A-A of FIG.

4 is a cross-sectional view taken along the line A-A of FIG.

5 is a cross-sectional view taken along the line A-A in FIG.

6 is a longitudinal cross-sectional view of the bottom of the outer peripheral portion of the cavity.

7 is a longitudinal sectional view of the main part of the female mold part, the first bush and the male mold part.

8 is an enlarged longitudinal sectional view for explaining a molding operation, in which main parts of the female mold part, the first bush and the male mold part are enlarged.

9 is a longitudinal cross-sectional view of the main part of the female mold part, the second bush and the male mold part.

10 is a longitudinal sectional view of the bottom of the outer circumferential portion of the cavity.

It is a longitudinal cross-sectional view of the bottom face of the outer peripheral part of a cavity.

It is a longitudinal cross-sectional view of the bottom face of the outer peripheral part of a cavity.

It is a longitudinal cross-sectional view of the principal part of a female mold part, the thin formation part of a male mold part.

It is a figure for demonstrating shaping | molding operation, It is an enlarged longitudinal cross-sectional view of the principal part and the thin part formation part of the male mold part.

15 is a longitudinal cross-sectional view of the main part of the female mold part, the first bush and the male mold part.

16 is an enlarged longitudinal sectional view of the main part of the female mold part, the second bush and the male mold part;

17 is an enlarged longitudinal sectional view of the main part of the female mold part, the second bush and the male mold part;

18 is an enlarged longitudinal sectional view of the main part of the female mold part, the second bush and the male mold part;

19 is a plan view of the bush.

20 is a cross-sectional view taken along line B-B in FIG. 19 with a synthetic resin injected;

FIG. 21 is a cross-sectional view taken along line B-B in FIG. 19 with a pressurized gas injected therein; FIG.

FIG. 22 is a cross-sectional view taken along the line B-B in FIG.

23 is a plan view of the bush.

FIG. 24 is a cross-sectional view taken along line C-C in FIG. 23 with a synthetic resin injected; FIG.

25 is a cross-sectional view taken along line CC of FIG. 23 with a pressurized gas injected therein;

FIG. 26 is a cross-sectional view taken along the line C-C in FIG.

27 is a partially enlarged view of FIG. 26.

It is a longitudinal cross-sectional view of a molded article.

<Code description>

1 fixed side assembly

6 Female Mold

12 heating medium passage

20 movable side assembly

26 Mold Gas

27 male mold part

28A, B gas injection furnace

29A, B gas discharge furnace

30, 31 overhang

30A, B, C protrusions

34 home

34A, B, C Groove

35, 35B Bushing 1

35A thin section

36, 37 overhang

36A, 37A protrusions

38, 39 taper

38A, 39A Taper Section

40 second bush

41 protrusions

41A, B, C protrusions

44 protrusions

47 Compression tanks

48, 49 runway

53, 54 Home

53A, B, C Groove

57, 58 protrusions

59A, B Groove

60 protrusions

61 home

62, 63 protrusions

65, 66 bush

Claims (15)

A female mold and a male mold, and after heating the cavity-forming surface side of the female mold, the molten synthetic resin is injected into a cavity formed between the female mold and the male mold, and pressurized gas is injected into the cavity. An injection molding apparatus in which the surface of the synthetic resin is pressed against the cavity forming surface of the female mold to pressurize it. The bottom surface of the cavity is formed of a bottom forming body and the male mold, and at least an upper end of the bottom forming body is placed into the cavity at least at an end portion of the bottom forming body and the male mold. To form a frame along the butt portion, and to form a groove between the protrusion and the male mold. When the molten synthetic resin is injected into the cavity and the pressurized gas is injected between the back surface of the synthetic resin and the cavity forming surface of the male mold, the synthetic resin is the butt portion of the bottom forming body and the male mold. Proceed towards Injection molding apparatus, characterized in that the synthetic resin at the front end is in contact with the protruding portion to be pushed into the groove. The method according to claim 1, And a first space extending in the horizontal direction and a cylindrical second space extending in the vertical direction communicating with the first space, wherein the first space is formed of the female mold and the male mold. In addition, the bottom surface of the second space is formed by the mold body as the bottom forming body for fixing and placing the male mold on the upper surface thereof, and the second space is formed by the female mold and the female mold. It is formed by a male mold and the mold body, Each of the upper end portions of the abutment portion between the mold body and the male mold is formed in the shape of a frame along the abutment portion, and the protrusions projecting upwardly so as to enter each other into the cavity, and the both protrusions abut each other. Injection molding apparatus characterized in that the groove is formed by a projection. The method according to claim 1, And a first space extending in the horizontal direction and a cylindrical second space extending in the vertical direction communicating with the first space, wherein the first space is formed of the female mold and the male mold. In addition, the bottom surface of the second space is formed by the mold body as the bottom forming body for fixing and placing the male mold on the upper surface thereof, and the second space is formed by the female mold and the female mold. It is formed by a male mold and the mold body, In the upper end of the mold body of the abutment portion of the male mold, the protrusion protruding upwardly so as to fit into the cavity is formed in a frame shape along the abutment portion, and the groove is formed between the protrusion and the male mold. Injection molding apparatus, characterized in that formed. The method according to claim 1, In order to form an opening in a molded article, the upper surface of the portion which is squeezed into the cavity and the top thereof contacts the female mold and is disposed on and fixed to the upper surface of the male mold forms a bush forming the bottom forming body. It is arranged and fixed on the upper surface of the male mold, An injection molding apparatus characterized in that the protrusion is formed to be squeezed into the cavity at the outer circumference of the fixed portion of the bush, and the groove is formed between the protrusion and the male mold. The method according to claim 1, In order to form an opening in a molded article, the upper surface of the portion which is squeezed into the cavity and the top thereof contacts the female mold and is disposed on and fixed to the upper surface of the male mold forms a bush forming the bottom forming body. It is fixed to the upper surface of the male mold, A first protrusion for gripping into the cavity and a second protrusion for gripping into the cavity so as to surround the first protrusion from the outside on an upper surface of the male mold as the protrusion; Forming the groove between the second protrusion and the first protrusion, An injection molding apparatus, wherein another groove is formed in the outer peripheral portion of the upper surface of the bush even with the first protrusion. The method according to claim 1, Arranging and installing a bush as the bottom forming body on an upper surface of the male mold, Protruding the protrusion to be plunged into the cavity into the outer peripheral portion of the upper surface of the bush, and forming the groove between the protrusion and the side forming the cavity of the female mold, And injecting the molten synthetic resin into the cavity and injecting the pressurized gas between the back surface of the synthetic resin and the bush, the synthetic resin being pushed into the groove beyond the projection. The method according to claim 1, The bush as the bottom forming body is fitted into the recess formed in the upper surface of the male mold, and fixed. The second protrusion, which protrudes into the cavity at the upper periphery of the upper surface of the male mold forming the concave portion while protruding the first protrusion as the protrusion to be pushed into the cavity at the upper peripheral portion of the bush, is higher than the first protrusion. Extrude, The groove is formed between the second protrusion and the first protrusion, When the molten synthetic resin is injected into the cavity, the molten synthetic resin is squeezed into the groove. Then, when the pressurized gas is supplied into the cavity, a pressurized gas layer is formed between the synthetic resin and the bush in the cavity. An injection molding apparatus, wherein the pressurized gas pushes the surface of the synthetic resin onto the cavity-forming surface of the female mold in a state in which the pressurized gas does not exceed the second protrusion, but pressurizes the upper surface of the first protrusion. The method according to claim 1, In order to form a thin portion in the molded article, an upper longitudinal section in which the upper portion of the mold is pushed into the cavity has a trapezoidal shape in which the upper bottom is shorter than the lower bottom, and a bush is provided on the upper surface of the male mold. Further provided, A protrusion having a quadrilateral portion perpendicular to the quadrilateral portion of the bush so as to be pushed into the cavity on the upper surface of the bush, When the molten synthetic resin is injected into the cavity, and the pressurized gas is injected between the rear surface of the synthetic resin and the cavity forming surface of the male mold, the pressurized gas passes over the top of the projecting portion and the quadrilateral portion of the projecting portion. Abutment formed by the quadrilateral of the bush, The pressurized gas that reaches the solid portion is pressed to push up the synthetic resin along the quadrilateral portion of the bush to press the synthetic resin between the upper surface of the bush and the female mold. The method according to claim 1, In order to form a thin portion in the molded article, an upper longitudinal section in which an upper portion thereof is squeezed into the cavity is formed on an upper surface of the male mold in which a thin portion having a trapezoidal shape whose upper bottom is shorter than the lower bottom is formed. A protrusion having a quadrilateral portion orthogonal to the quadrilateral portion of the thin film forming portion to be pushed into the cavity on the upper surface of the thin film forming portion, When the molten synthetic resin is injected into the cavity, and the pressurized gas is injected between the rear surface of the synthetic resin and the cavity forming surface of the male mold, the pressurized gas passes over the top of the projecting portion and the quadrilateral portion of the projecting portion. The thin portion formed by the quadrilateral portion is in contact with, The pressurized gas reaching the solid portion is pressed to push up the synthetic resin along the quadrilateral portion of the thin film forming portion to press the synthetic resin between the upper surface of the thin film forming portion and the female mold. The method according to claim 8 or 9, Injection molding apparatus characterized in that each tapered portion formed on the top of the protrusion. The method according to claim 1, In order to form a thin portion in the molded article, an upper longitudinal section in which the upper portion of the mold is pushed into the cavity has a trapezoidal shape in which the upper bottom is shorter than the lower bottom, and a bush is provided on the upper surface of the male mold. Further provided, On the upper surface of the male mold located in the vicinity of the bush to form a first projection to be plunged into the cavity, respectively, A second protrusion formed on an upper surface of the male mold and having a quadrangle orthogonal to the quadrangle of the first protrusion, the second protrusion penetrating into the cavity; When the molten synthetic resin is injected into the cavity, and the pressurized gas is injected between the back surface of the synthetic resin and the cavity forming surface of the male mold, the pressurized gas passes over the second protrusion and the first protrusion. Reach the quadrilateral of the first protrusion, Pressing the pressurized gas to push the back surface of the synthetic resin in the direction orthogonal to the quadrangle of the first protrusion and the quadrangle of the second protrusion, between the upper surface of the bush and the female mold. Injection molding apparatus, characterized in that for pressing the synthetic resin. The method according to claim 1, A bush on the upper surface of the male mold is further provided with a bush, which is pushed into the cavity to form an opening in a molded article, the upper end of which is in contact with the female mold, On the upper surface of the male mold to form a protrusion for gripping into the cavity to surround the bush from the outside, Forming a groove between the bush and the protrusion, When the molten synthetic resin is injected into the cavity and the pressurized gas is injected between the back surface of the synthetic resin and the cavity forming surface of the male mold, the synthetic resin is brought into the groove by pressurization of the pressurized gas. By pressing the synthetic resin into the groove, the pressurized gas flows to a portion other than the groove to increase the volume of the pressurized gas in the cavity, thereby increasing and curing the density of the synthetic resin around the bush so that the pressurized gas is Injection molding apparatus, characterized in that to prevent pulling up along the side. The method according to claim 1, A bush on the upper surface of the male mold is further provided with a bush, which is pushed into the cavity to form an opening in a molded article, the upper end of which is in contact with the female mold, A first groove is formed between the first protrusion and the first protrusion that is pushed into the cavity at an outer circumference of the upper surface of the bush, A second protrusion is formed on the upper surface of the male mold to squeeze into the cavity to surround the first protrusion from the outside; Forming a second groove between the second protrusion and the first protrusion, When the molten synthetic resin is injected into the cavity and the pressurized gas is injected between the back surface of the synthetic resin and the cavity forming surface of the male mold, the synthetic resin passes over the second protrusion by pressurization of the pressurized gas. Reach into the second groove, and proceed further to reach the first groove beyond the first protrusion,  By pressing the synthetic resin into the first groove and the second groove, the pressurized gas flows into a portion other than the first and second grooves to increase the volume of the pressurized gas in the cavity, thereby increasing the volume of the synthetic resin around the bush. Injection molding apparatus, characterized in that to prevent the pressure gas is drawn along the side of the bush by increasing the density of the curing. The method according to claim 1, A bush on the upper surface of the male mold is further provided with a bush, which is pushed into the cavity to form an opening in a molded article, the upper end of which is in contact with the female mold, A protrusion is formed in the outer peripheral portion of the upper surface of the bush into the cavity, and a groove is formed between the protrusion and the protrusion. When the molten synthetic resin is injected into the cavity, and the pressurized gas is injected between the rear surface of the synthetic resin and the cavity forming surface of the male mold, the synthetic resin is brought into contact with the protruding portion by pressurization of the pressurized gas. Injection molding apparatus characterized in that the return to the female mold is prevented. delete

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