RU2401197C2 - Method of injection-moulding and device to this end (versions) - Google Patents

Abstract

FIELD: metallurgy. ^ SUBSTANCE: steam is fed in heat carrier channel 12 made in mould negative part 6 to start heating the side with surface that form the mould cavity to preset temperature and, then mould is closed. Now, heating is terminated for preset amount of synthetic resin J is injected into cavity S. Thereafter, compressed is injected into space between rear surface of synthetic resin J and cavity-forming surface of mould positive part 27 to force said resin toward cavity-forming surface to hold synthetic resin. In holding, cooling water is fed into channel 12 to solidify synthetic resin front surface on the side of mould negative part 6. Synthetic resin solidified to certain degree, pressure is removed to let compressed gas out from injection moulding equipment. Compressed gas released, cooling air is forced into space between synthetic resin rear surface and cavity-forming surface of the mould positive part 27. ^ EFFECT: ruling out of moulded product and irregularity of transition in mould, reduced moulding time. ^ 15 cl, 40 dwg

Description

The present invention relates to a method for injection molding and equipment for injection molding. More specifically, the present invention relates to a method for injection molding, including the step of injecting compressed gas into the space between the synthetic resin located in the cavity and the cavity forming the cavity, and to injection molding equipment that uses this injection molding method .

As disclosed, for example, in Japanese Patent Application Laid-Open Publication No. 06-254924, a method was proposed in which the surface forming the cavity from the front surface side and intended to form the molded product side with the front surface is heated before injection of the molten synthetic resin, thereby trying to improve the transfer property.

However, the molten synthetic resin moves inside the cavity during its cooling, which creates problems due to the insufficiently uniform spreading of the synthetic resin to the end portions and the solidification of the molten synthetic resin when it flows inside the cavity, especially if the plate thickness of the molded product increases. In addition, the molding of the synthetic resin took a longer period of time, since the inductor heated by high-frequency induction heating oscillates while it is located between the stationary mold and the movable mold.

In view of the above problems, the present invention is directed to eliminating the deformation of the molded product and uneven transfer in the mold as much as possible and to reduce the molding time.

The first invention relates to a method of injection molding, comprising injecting molten synthetic resin into a cavity formed between the negative part of the mold and the positive part of the mold, for molding it, which includes the following operations, which are carried out:

heating the side of the negative part of the mold provided with the cavity forming surface by supplying a coolant to the channel of the negative part of the mold intended for the coolant to initiate an increase in temperature of the side with the cavity forming surface;

injecting a predetermined amount of molten synthetic resin into the cavity after stopping the temperature increase;

injection of compressed gas into the space between the rear side of the synthetic resin and the cavity-forming surface of the positive part of the mold after injection of the molten synthetic resin to provide a time delay (delay in closure of the mold) by pressing the front surface of the synthetic resin to the cavity-forming surface of the negative part of the mold ; and

curing the synthetic resin on the side of the negative part of the mold provided with the cavity forming surface by supplying a coolant to the channel of the negative part of the mold intended for the coolant while providing a time delay by means of compressed gas.

The second invention relates to a method of injection molding in accordance with paragraph 1 of the claims, further comprising the step of: injecting cooling gas into the space between the rear surface of the synthetic resin and the cavity forming the surface of the positive part of the mold after displacing the compressed gas from the injection molding equipment pressure when the curing of the synthetic resin occurs to a certain extent.

The third invention relates to a method of injection molding in accordance with paragraph 1 of the claims, in which the compressed gas, subjected to injection into the cavity, is captured in the tank through the space between the intended for the formation of a thin wall part and the positive part of the mold so that cause excessive compression to a greater extent than necessary, in the part where the synthetic resin can be pressed against the cavity forming the surface of the negative part of the mold, when the part to form a thin Tenki, designed to form a thin-walled part on the molded product, is provided in the concave part formed on the upper surface of the positive part of the mold, while the compressed gas collected in the reservoir is simultaneously supplied to the part where the compressed gas is not sufficiently compressed by means of this space.

The fourth invention relates to a method of injection molding in accordance with paragraph 1 of the claims, in which the compressed gas, subjected to injection into the cavity, is captured in the tank through the space between the part intended to form the hole, and the positive part of the mold so that cause excessive compression to a greater extent than necessary, in the part where the synthetic resin can be pressed against the cavity forming the surface of the negative part of the mold, when the part to form a hole, designed to form a part with a hole in the molded product, is provided in the concave part formed on the upper surface of the positive part of the mold, while the compressed gas collected in the tank is simultaneously supplied to the part where the compressed gas is not sufficiently compressed.

The fifth invention relates to equipment for injection molding, which is configured to enable injection of molten synthetic resin into the cavity formed between the negative part of the mold and the positive part of the mold to form it:

in which the channel intended for the coolant is formed so that it passes along the cavity, which allows the coolant or coolant to pass into it, and

in which channels for pumping gas are formed to supply compressed gas to the cavity;

heating the side of the negative part of the mold provided with the cavity forming surface by supplying a coolant to the channel of the negative part of the mold intended for the coolant to initiate an increase in temperature of the side with the cavity forming surface;

injecting a predetermined amount of molten synthetic resin into the cavity after stopping the temperature increase;

injection of compressed gas into the space between the rear side of the synthetic resin and the cavity-forming surface of the positive part of the mold after injection of the molten synthetic resin to provide a time delay (delay in closure of the mold) by pressing the front surface of the synthetic resin to the cavity-forming surface of the negative part of the mold ; and

curing the synthetic resin on the side of the negative part of the mold provided with the cavity forming surface by supplying a coolant to the channel of the negative part of the mold intended for the coolant while providing a time delay by means of compressed gas.

A sixth invention relates to injection molding equipment configured to inject molten synthetic resin into a cavity formed between the negative part of the mold and the positive part of the mold after heating the side of the negative part of the mold provided with the cavity forming surface injecting compressed gas into the space between the rear surface of the synthetic resin and the cavity-forming surface of the positive part of the mold and ensuring that time holding (delay of mold closure) by pressing the front surface of the synthetic resin to the cavity forming the surface of the negative part of the mold:

in which the lower surface of the cylindrical part of the cavity, formed from a space extending in the horizontal direction, and a cylindrical space that is continuous with respect to this space and extends in the vertical direction, is formed from the base part of the mold and the positive part of the mold to be fastening to the concave portion formed on the base portion of the mold; and

in which a protruding part protruding upward so that it enters the cavity is formed at each end portion of the upper surface of the mating part between the base part of the mold and the positive part of the mold so that it is formed with a frame shape along the mating part, and both protruding parts form a groove in the upper part when both protruding parts mate with each other.

A seventh invention relates to injection molding equipment that is configured to inject molten synthetic resin into a cavity formed between the negative part of the mold and the positive part of the mold after heating the side of the negative part of the mold provided with the cavity forming surface injecting compressed gas into the space between the rear surface of the synthetic resin and the cavity-forming surface of the positive part of the mold and providing Time delays (delayed closure of the mold) by pressing the front surface of the synthetic resin to the cavity forming the surface of the negative part of the mold:

in which the lower surface of the cylindrical part of the cavity, formed from a space extending in the horizontal direction, and a cylindrical space that is continuous with respect to this space and extends in the vertical direction, is formed from the base part of the mold to which the positive part of the press is attached forms; and

in which the protruding part, protruding upward so that it enters the cavity, is formed along the mating part so that it is formed with the shape of a frame at the end portion of the upper surface of the base part of the mold at the part mating with the positive part of the mold, and a groove is formed between the protruding part and the positive part of the mold.

The eighth invention relates to injection molding equipment configured to inject molten synthetic resin into a cavity formed between the negative part of the mold and the positive part of the mold after heating the side of the negative part of the mold provided with the cavity forming surface injecting compressed gas into the space between the rear surface of the synthetic resin and the cavity-forming surface of the positive part of the mold and providing Time delays (delayed closure of the mold) by pressing the front surface of the synthetic resin to the cavity forming the surface of the negative part of the mold:

in which the liner, the upper part of which enters the cavity and the longitudinal plane of the upper part of which has a trapezoidal shape, having a shorter upper base and a longer lower base, and which forms a thin-walled part on the molded product, is brought into contact with a concave part formed on the upper the surface of the positive part of the mold, with the possibility of fixing on it; and

in which a protruding portion having an inclined side portion that is approximately orthogonal to the inclined side portion of the liner is formed on the upper surface of the liner so that it enters the cavity.

The ninth invention relates to injection molding equipment that is configured to inject molten synthetic resin into a cavity formed between the negative part of the mold and the positive part of the mold after heating the side of the negative part of the mold provided with the cavity forming surface injecting compressed gas into the space between the rear surface of the synthetic resin and the cavity-forming surface of the positive part of the mold and providing Time delays (delayed closure of the mold) by pressing the front surface of the synthetic resin to the cavity forming the surface of the negative part of the mold:

in which the part intended for the formation of a thin wall, the longitudinal plane of the upper portion of which has a trapezoidal shape having a shorter upper base and a longer lower base, and which forms a thin-walled part on the molded product, is formed as a protrusion on the upper surface of the positive part of the mold so as to allow entry of the upper portion of the protrusion into the cavity; and

wherein the protruding portion having an inclined side portion approximately orthogonal to the inclined side portion of the portion intended to form a thin wall is formed on the upper surface of the portion intended to form the thin wall such that the protruding portion enters the cavity.

The tenth invention relates to injection molding equipment in accordance with any one of the eighth or ninth invention, in which a tapered portion is formed in an upper portion of each of the protruding portions.

The eleventh invention relates to injection molding equipment configured to inject molten synthetic resin into a cavity formed between the negative part of the mold and the positive part of the mold after heating the side of the negative part of the mold provided with the cavity forming surface injecting compressed gas into the space between the rear surface of the synthetic resin and the cavity-forming surface of the positive part of the mold and providing Nia time lag (delay mold closure) by urging the front surface of the synthetic resin to the cavity forming surface portion of the negative mold:

in which the liner, the upper part of which enters the cavity and the longitudinal plane of the upper part of which is trapezoidal, having a shorter upper base and a longer lower base, is brought into contact with the concave part formed on the upper surface of the positive part of the mold, with the possibility fixing on it;

in which the first protruding part entering the cavity is formed on the upper surface of the positive part of the mold located next to the liner; and

wherein a second protruding portion having an inclined side portion approximately orthogonal to the inclined side portion of the first protruding portion is formed on the upper surface of the positive portion of the mold so that the second protruding portion enters the cavity.

The twelfth invention relates to injection molding equipment that is configured to inject molten synthetic resin into a cavity formed between the negative part of the mold and the positive part of the mold after heating the side of the negative part of the mold provided with the cavity forming surface injecting compressed gas into the space between the rear surface of the synthetic resin and the cavity-forming surface of the positive part of the mold and providing Ia time delay (delay mold closure) by urging the front surface of the synthetic resin to the cavity forming surface portion of the negative mold:

in which the liner, which enters the cavity and the upper part of which comes into contact with the negative part of the mold to form part with a hole in the molded product, is brought into contact with the concave part formed on the upper surface of the positive part of the mold, with the possibility of fixing on her; and

in which the protruding part entering the cavity is formed on the outer peripheral part of the liner, and a groove is also formed between the protruding part and the outer peripheral part.

The thirteenth invention relates to injection molding equipment configured to inject molten synthetic resin into a cavity formed between the negative part of the mold and the positive part of the mold after heating the side of the negative part of the mold provided with the cavity forming surface injecting compressed gas into the space between the rear surface of the synthetic resin and the cavity-forming surface of the positive part of the mold and providing Ia time delay (delay mold closure) by urging the front surface of the synthetic resin to the cavity forming surface portion of the negative mold:

in which the liner, which enters the cavity and the upper part of which comes into contact with the negative part of the mold to form part with a hole in the molded product, is brought into contact with the concave part formed on the upper surface of the positive part of the mold, with the possibility of fixing on her;

in which the first protruding part entering the cavity is formed on the outer peripheral part of the liner, and a groove is also formed between the first protruding part and the outer peripheral part;

in which the second protruding part entering the cavity is formed on the upper surface of the positive part of the mold so that it surrounds the first protruding part from the outside; and

in which a groove is formed between the second protruding part and the first protruding part.

The fourteenth invention relates to injection molding equipment configured to inject molten synthetic resin into a cavity formed between the negative part of the mold and the positive part of the mold after heating the side of the negative part of the mold provided with the cavity forming surface injecting compressed gas into the space between the rear surface of the synthetic resin and the cavity-forming surface of the positive part of the mold and providing eniya time lag (delay mold closure) by urging the front surface of the synthetic resin to the cavity forming surface portion of the negative mold:

in which the liner is brought into contact with the concave part formed on the upper surface of the positive part of the mold, with the possibility of fixing on it; and

in which the protruding part entering the cavity is formed on the upper surface of the liner, and a groove is also formed between the protruding part and the side surface defining the boundaries of the cavity of the negative part of the mold.

The fifteenth invention relates to injection molding equipment that is configured to inject molten synthetic resin into a cavity formed between the negative part of the mold and the positive part of the mold after heating the side of the negative part of the mold provided with the cavity forming surface injecting compressed gas into the space between the rear surface of the synthetic resin and the cavity-forming surface of the positive part of the mold and providing Ia time delay (delay mold closure) by urging the front surface of the synthetic resin to the cavity forming surface portion of the negative mold:

in which the liner is brought into contact with the concave part formed on the upper surface of the positive part of the mold, with the possibility of fixing on it;

in which the first protruding part entering the cavity is formed on the upper surface of the liner and the second protruding part entering the cavity is formed on the peripheral edge part of the hole on the upper surface of the positive part of the mold with a concave part, the second protruding part protruding onto a large height than the first protruding part; and

in which a groove is formed between the second protruding part and the first protruding part.

In accordance with the present invention, the deformation of the molded product and the defect of the molded product due to uneven transfer in the mold can be eliminated as much as possible, and the molding time can be reduced. In addition, with regard to the molded product having a thin-walled part, the uneven transfer in the mold can be enhanced in the thin-walled part.

The invention is illustrated in the drawings, where:

figure 1 is a longitudinal vertical front view of the equipment for injection molding;

figure 2 is a view in plan of the positive part of the mold;

figure 3 is a section of the positive part of the mold of figure 2, made along the line aa;

figure 4 is a section of the positive part of the mold of figure 2, made along the line aa and shown in the injection state of the synthetic resin;

figure 5 is a section of the positive part of the mold of figure 2, made along the line aa and shown in the holding state of the synthetic resin;

6 is a longitudinal, sectional view of the lower surface of the outer peripheral part of the cavity;

Fig.7 is a longitudinal section illustrating the main parts of the negative part of the mold, the first liner and the positive part of the mold;

Fig is an enlarged longitudinal section illustrating the main parts of the negative part of the mold, the first liner and the positive part of the mold to explain the molding process;

Fig.9 is a longitudinal section illustrating the main parts of the negative part of the mold, the second liner and the positive part of the mold;

figure 10 is a longitudinal, made in cross section view of the lower surface of the outer peripheral part of the cavity;

11 is a longitudinal, sectional view of the lower surface of the outer peripheral part of the cavity;

12 is a longitudinal sectional view of the lower surface of the outer peripheral portion of the cavity;

Fig is a longitudinal section illustrating the main parts intended for the formation of a thin wall of the parts of the negative part of the mold and the positive part of the mold;

Fig is an enlarged longitudinal section illustrating the main parts intended for the formation of a thin wall of the parts of the negative part of the mold and the positive part of the mold to explain the molding process;

Fig is a longitudinal section illustrating the main parts of the negative part of the mold, the first liner and the positive part of the mold;

Fig is an enlarged longitudinal section illustrating the main parts of the negative part of the mold, the second liner and the positive part of the mold;

Fig is an enlarged longitudinal section illustrating the main parts of the negative part of the mold, the second liner and the positive part of the mold;

Fig is an enlarged longitudinal section illustrating the main parts of the negative part of the mold, the second liner and the positive part of the mold;

Fig is a view in plan of the liner;

Fig. 20 is a sectional view of the liner of Fig. 19 taken along line BB and shown in an injection state of synthetic resin;

Fig.21 is a cross-section of the liner of Fig.19, made along the line BB and shown in a state of injection of compressed gas;

FIG. 22 is a sectional view of the insert of FIG. 19 taken along line BB and shown in a holding state;

Fig is a view in plan of the liner;

Fig.24 is a cross-section of the liner of Fig.23, taken along the line CC and shown in the injection state of the synthetic resin;

Fig.25 is a cross-section of the liner of Fig.23, made along the line CC and shown in a state of injection of compressed gas;

FIG. 26 is a sectional view of the insert of FIG. 23 taken along line CC and shown in a holding state;

Fig.27 is a partial enlarged view of Fig.26; and

Fig is a longitudinal view in plan of the molded product.

Embodiments of the present invention will be described below with reference to the drawings. First, the entire configuration of injection molding equipment will be described with reference to FIG. Reference numeral 1 denotes a fixed side assembly attached to a not shown fixing plate by bolts, wherein the fixed side assembly 1 includes a first fixed side base plate 2, a second fixed side base plate 3 attached to a first fixed side base plate 2 by bolts, the third fixed side base plate 4, attached to the second fixed side base plate 3 by means of bolts, the negative part 6 of the mold (fixed part mold), which is located in the concave part of the third fixed side base plate 4 and is attached to the third fixed side base plate 4 by means of bolts, an installation ring 7, which is provided in a location adjacent to the fixing plate of the first fixed side base plate 2, and provides the installation of the first fixed side base plate 2 in a predetermined position relative to the fixing plate, the sprue sleeve 8, located next to the mounting ring 7, and other elements.

A central gate 9, designed to allow molten synthetic resin injected from an unshown injection nozzle to pass through it, is formed in the center of the sprue sleeve 8, a spreader 10 is formed at the lower end of its central part, and, in addition, a lot of sprue holes 11 are formed serving as the outputs of the distributor gate 10. In addition, reference numeral 12 denotes a channel for the coolant formed in the section adjacent to the cavity S of the active part 6 of the mold so that it passes along the cavity S, which allows hot steam to pass as a coolant or cooling water as a coolant through the channel 12 intended for the coolant, as a result of which the surface provided with the cavity forming is heated or cooled side of the negative part 6 of the mold.

Reference numeral 20 denotes a movable side assembly that is attached to a movable plate not shown by bolts, wherein the movable side assembly 20 includes a first movable side base plate 21, a second movable side base plate 22 attached to the first movable side base plate 21 by bolts, a third movable side base plate 23 attached to the first movable side base plate 21 by means of bolts so that it surrounds the second movable side base plate 22, the fourth movable side a base plate 24 attached to the third movable side base plate 23 by bolts, a base part or mold base 26 brought into contact with the concave part of the fourth movable base plate 24 so that it can be attached to the fourth movable base plate 24 having the shape almost rectangular parallelepiped, the positive part 27 of the mold, brought into contact with the concave part of the base part 26 of the mold with the possibility of its attachment to the base part 26 of the mold, and other elements.

A guide rod (not shown) protruding upward from the third movable side base plate 23 is inserted into the guide hole made in the third fixed side base plate 4 to guide it through the guide hole, thereby allowing the movable side assembly 20 to be moved up and down .

Further, as shown in FIG. 2, which is a plan view having a rectangular shape, the positive part 27 of the mold (the movable part of the mold) in a plane view, and in FIG. 3, which is a sectional view taken along line A-A in FIG. 2, a cavity S, which is formed, for example, from a rectangular zone extending in the horizontal direction in a plane view, and, for example, from a rectangular cylindrical zone extending in the vertical direction from the outer peripheral part of the rectangular zone, serves for the formation of a molded product having the shape of a box top cover with an open top surface (having a rectangular horizontal surface and four vertical surfaces extending vertically downward from each side of the horizontal surface). In this case, the continuous thin-walled part U, which has a predetermined width and a contour having the shape of a rectangular frame (string-like shape), is formed on the side of the rear surface of the molded product. The four sides of the thin-walled portion U may have the same thickness or may have different thicknesses.

Reference numerals 28A and 28B denote gas injection channels for supplying compressed gas (eg, nitrogen gas, air, or the like) from an unapproved source of compressed gas to the cavity S through the supply valves. Reference numerals 29A and 29A denote gas discharge channels for discharging compressed gas located in cavity S from injection molding equipment through exhaust valves.

As shown in FIG. 6, the mating part between the mold base portion 26 and the mold positive portion 27 is located in the middle of the lower surface of the outer peripheral part of the cavity S forming the vertical surface of the mold to be formed, and the lower surface of the outer peripheral part of the cavity S is formed by the base part 26 of the mold and the positive part 27 of the mold. The end sections of the upper surface of the mating part between the base part 26 of the mold and the positive part 27 of the mold are provided with protruding parts designated respectively 30, 31, while the end sections of the upper surface protrude up to the same height so that they enter the cavity S and form a configuration with a shape such as a rectangular frame (string-shaped). The outer side portion of the upper portion of the protruding portion 31 is partially cut away, and thus, when the protruding portions 30, 31 are mated with each other, their lower portions come into tight contact with each other, while their upper portions form a groove 34.

In other words, the protruding portion 30 of the mold base portion 26 is formed such that each of the side surfaces of the mold base portion 26 defining the boundaries of the concave portion for receiving the positive mold portion 27 extends vertically upward so that it extends outward with an inclination, which leads to the fact that it forms an approximately right-angled triangle in the longitudinal plane having an angle at the apex of about 20 to 45 degrees. In addition, the protruding part 31 of the positive mold part 27 is formed so that each of the side surfaces of the positive mold part 27, which is in contact with each of the side surfaces of the mold base part 26 forming the concave part, extends vertically upwards to the same height as the protruding part 30, and subsequently the outer part of the upper portion of the protruding part 31 is partially cut off, then the side surface of the positive part of the mold is inclined where it extends inward so that about leads to the fact that it forms an approximately rectangular triangle in the longitudinal plane, having an angle at the apex of about 20 to 45 degrees. Essentially, a groove 34 having a width at which the compressed gas G cannot “enter” inward when the protruding parts 30 and 31 are mated with each other (for example, a width equal to or less than 0.5 mm) is formed in the upper portion of the protrusions .

Reference numeral 32 denotes a concave portion formed on the upper surface of the positive mold portion 27 to form a rib protruding downward toward the lower surface of the molded product, and reference numeral 33 denotes a concave portion formed on the upper surface of the mold positive portion 27 similarly designed to form a hollow cylindrical portion protruding downward towards the lower surface of the molded product.

7, reference numeral 35 denotes a first insert as a part that is intended to form a thin wall and which is brought into contact with the concave part of the upper surface of the positive mold part 27, the concave part having a predetermined width and having a continuous contour with a shape similar to a rectangular frame (string-shaped form), and the first liner 35 is configured so that its upper part enters the cavity S, the longitudinal plane of the upper part has the shape of an isosceles trapezoid, having a shorter upper base and a longer lower base, while the distance between the plane 42 of the upper part formed on the entire peripheral part of the upper part of the first liner 35 and the negative part 6 of the mold is less than the remaining parts of the first liner 35, and a continuous contour having a predetermined width, as described above, promotes the formation of a thin-walled portion U on a molded product having a shape similar to a rectangular frame (string-shaped).

The protruding parts 36, 37, which enter the cavity S, are formed so that the protruding parts 36, 37 protrude from the outer peripheral part and the inner peripheral part of the upper surface of the first liner 35 and are formed with a rectangular frame shape (string-shaped) in a plan view, and the outer surface and the inner surface of the first liner 35 extend up to a height that is less than the height of the plane 42 of the upper parts, and have a slope when they extend inward, which leads to the fact that in the longitudinal plane they have the shape n approximately rectangular triangle with an angle at the apex, comprising, for example, from 20 to 40 degrees, and also have narrowed parts 38, 39 in their upper sections. That is, the height of the intersection between the inclined side sections forming the protruding parts 36, 37 and the inclined side section of the first liner 35 having a longitudinal plane in the form of an isosceles trapezoid is equal to the height of the lower surface defining the boundaries of the cavity S, both inclined side sections intersect at an angle of approximately 90 degrees, that is, at an almost right angle, and the upper portions of the protruding parts 36, 37 are made with narrowed parts, respectively marked 38, 39, which have good heat conduction.

9, reference numeral 40 denotes a second insert as a part for forming an opening for forming a through hole in the molded product, the second insert being brought into contact with the concave part of the upper surface of the positive part 27 of the mold with the possibility of mounting on it , has the shape of an approximately rectangular parallelepiped and has an upper end in contact with the negative part 6 of the mold when clamping the mold. In other words, the second liner 40 has a locking portion 40A that has a large sectional area in the plane and which is brought into contact with the concave portion of the upper surface of the positive mold portion 27, and a small portion 40B that is provided on the upper portion of the locking portion 40A with a step for the formation of a through hole in the molded product, while the upper surface of the small part 40B is in contact with the negative part 6 of the mold, and the outer peripheral end portion of the upper surface of the second liner 40, i.e. A narrow peripheral end portion of the upper surface of the through-hole portion 40B is provided with a protruding portion 41 with a smaller width so that each of the outer surfaces of the second liner 40 extends upward so that it enters the cavity S.

In addition, the protruding part 44 is located on the upper surface of the positive part 27 of the mold so that it provides a groove 53 with a small gap between the protruding part 44 and the protruding part 41 and surrounds the protruding part 41 from the outside in a state where the second liner 40 is in interacting with the concave portion of the upper surface of the positive portion 27 of the mold. In this case, the protruding part 41 of the second liner 40 has the same height as the protruding part 44 of the positive mold part 27 and the depth of the groove 54 having the width of the opening formed between them at which the compressed gas G cannot pass inwardly into the groove, slightly less than the depth of the cavity S. Thus, the protruding part 41 of the second insert 40 and the protruding part 44 of the positive part 27 of the mold are formed with the shape of a rectangular frame (string-shaped) in the plan view.

1 and 3, reference numeral 48 denotes a plurality of output and input channels for establishing communication between the space available between the first insert 35 and the positive mold part 27 and the compression reservoir 47, and reference numeral 49 denotes the output and input channel 49 for establish communication between the space available between the second liner 40 and the positive part 27 of the mold, and the compression tank 47. The compression tank 47 is connected to the space outside of the injection molding equipment By means of an outlet channel 50 with an outlet valve.

In the above-described configuration, during injection molding, hot steam is first supplied as a coolant to the channel 12 of the negative mold part 6 for the heating medium to heat the side of the negative mold part 6 provided with the cavity forming the surface, and the temperature rises to a predetermined temperature in the interval from 80 to 200 degrees in accordance with the type of synthetic resin to be injected into the cavity S, as a result of which the fixed the lateral node 1 and the movable lateral node 20 with the clamping of the mold (see figure 3). As described above, the temperature increase can begin at the same time as the mold clamp, or it can start after the mold clamp, in addition to the case when the mold clamp is performed after the temperature increase starts.

When the temperature of the negative side part 6 of the mold provided with the cavity forming surface reaches a predetermined temperature, the temperature is stopped increasing by stopping the supply of hot steam, the injection nozzle is inserted into the gate 8 and the molten synthetic resin J is injected into the cavity S between the positive part 27 of the press mold and negative part 6 of the mold from the sprue hole 11 along the central sprue 9. In this case, the molten synthetic resin J is injected in an amount of ranging from equal to or greater than 80 weight percent to equal to or less than 98 weight percent, for example, approximately 90 weight percent, from the free space of cavity S (see FIG. 4).

When molten synthetic resin J is injected in an amount of approximately 90 weight percent, compressed gas G in an amount of approximately 10 weight percent of the free space of cavity S is supplied from a source of compressed gas to cavity S through a feed valve and through channels 28A, 28B for injection gas. Compressed gas G is injected into the space between the rear surface of the molten synthetic resin J and the cavity-forming surface of the positive mold part 27, thereby providing a time delay by pressing the surface of the molten synthetic resin J to the cavity-forming surface of the positive mold part 6 (see figure 5). Accordingly, the appearance of surface recesses on the surface of the molded product is suppressed, and the transfer property is improved, as a result of which the appearance problem with defects is eliminated as much as possible.

When the compressed gas G is injected, that is, immediately before the injection or immediately after the compressed gas G is injected, or during the injection of the compressed gas G, the cooling water is supplied to the coolant channel 12, made in the negative part 6 of the mold, to cause the curing of the synthetic resin J at the side of the negative mold part 6 provided with the cavity forming surface. In this case, the surface of the synthetic resin J is cooled while maintaining a time delay with the help of compressed gas, the injection is stopped when the synthetic resin J hardens to a certain extent, for example, to the extent that it is possible to give a certain shape to the synthetic resin, and then compressed gas G, located inside the cavity S, is removed from the equipment for injection molding. After complete removal of the compressed gas from the injection molding equipment, cold air is introduced instead of the compressed gas into the space between the rear surface of the synthetic resin and the cavity-forming surface of the positive mold part 27 through the gas injection channels 28A, 28B. In other words, the back surface of the synthetic resin (provided with the cavity-forming surface of the side of the positive mold part 27) cools at a moment later than the moment of cooling of the front surface of the synthetic resin (provided with the cavity-forming surface of the side of the negative mold part 6), when a temperature that is equal to or slightly lower than the cooling temperature when cooling the front surface of the synthetic resin.

Therefore, when the back surface of the synthetic resin was not cooled, warping of the molded product could occur due to differences in shrinkage between the side with the front surface and the side with the back surface in accordance with the temperature difference. However, the above-described cooling process provides the opportunity to reduce the molding time, as well as overcome the problem of shrinkage of the molded product. In addition, the reason that the temperature of the back side of the synthetic resin J is reduced to a temperature slightly lower than the temperature of the front surface of the synthetic resin J is because the molded product is deformed by the ejector pin when the molded product is removed from the mold, and the reason , in which the temperature of the back side of the synthetic resin is reduced by cooling to a temperature almost equal to the temperature of the front surface of the synthetic resin chaetsya in further reducing the molding time, provided that there is no problem of deformation caused by the ejector pin.

After curing the synthetic resin to a degree sufficient to extract it from the cavity S, the injection of cooling air into the cavity S and the supply of cooling water to the coolant channel 12, made in the negative part 6 of the mold, is stopped so that the mold can subsequently be opened , remove the molded product from the mold by means of the ejector pin and prepare again for the further manufacture of the molded product, as described above.

In this case, when the compressed gas G is injected into the space between the molten synthetic resin J and the cavity-forming surface of the positive mold part 27 and when the front surface of the molten synthetic resin J is pressed against the cavity-forming surface of the positive mold part 6, it is necessary to hold the synthetic resin, so that the molten synthetic resin J spreads over all corners of the cavity S and that the density of the molten synthetic resin J is a uniform density, as a result of which attained good transfer property. Specific embodiments for achieving the foregoing will be described below.

First, an explanation is made with reference to FIG. 6 with respect to the molding process on the lower surface of the outer peripheral part of the cavity S, which is the place where the molten synthetic resin J hardly spreads with a uniform density. That is, the lower surface of the outer peripheral part of the cavity S is formed from the base part 26 of the mold and the positive part 27 of the mold, and the mating part between the base part 26 of the mold and the positive part 27 of the mold is located in the middle of the cavity S to form a vertical the surface of the molded product, so that when a certain amount of compressed gas G is supplied under pressure to the cavity S through the channels 28A, 28B for injecting gas, the internal space of the cavity S shows a state similar to the illustrated and figa, and when a larger amount of compressed gas J will be supplied under pressure, the molten synthetic resin J will additionally spread towards the mating part between the base part 26 of the mold and the positive part 27 of the mold, that is, towards the end parts of the cavity S.

In this case, when the front surface of the molten synthetic resin J is slightly cured during its movement, the upper end of the synthetic resin J is in contact with the protruding parts 30, 31 of the mold base portion 26 and the mold positive portion 27 (see FIG. 6B) , the synthetic resin J is included in the portion of the groove 34 having a width at which the compressed gas G cannot “enter” inside (for example, a width equal to or less than 0.5 mm), and the slightly hardened front surface of the synthetic resin J is torn, which allows softer syn Tetic resin to go outside. Accordingly, the molten synthetic resin J begins to spread to the mating part between the mold base portion 26 and the positive mold part 27, i.e., to the end portion of the cavity S. Namely, since the softer molten synthetic resin J which has come out is included in the whole a groove 34, the passage of compressed gas around the negative part 6 of the mold or its leakage out of the injection molding equipment through the gap between the negative part 6 of the mold and the base part 26 of the mold is prevented, front The synthetic resin surface can be properly aged by pressing the front surface of the synthetic resin against the cavity-forming surface of the negative mold part 6 due to the compressed gas.

In this case, a thin rib remains on the molded product due to the presence of a groove 34; however, the rib does not protrude outward so that it extends beyond the contour of the molded product, so that the molded product will not have problems that would be associated with either the functioning or appearance of the molded product.

Next, the molding process around the first liner 35, where the molten synthetic resin J hardly spreads with a uniform density of the molten synthetic resin, is described with reference to FIGS. 7 and 8. First, when the compressed gas G is injected into the cavity S through injection channels 28A, 28B gas so that the front surface of the molten synthetic resin J is pressed against the cavity forming the surface of the negative part 6 of the mold to ensure the exposure of the synthetic resin, the compressed gas G reaches the side surfaces of the protruding parts 36, 3 7 of the first liner 35 for contacting them.

In addition, when the compressed gas G is injected into the cavity S, the compressed gas rises and reaches the narrowed parts 38, 39 on the protruding parts 36, 37 (see FIG. 8B), passes over the narrowed parts 38, 39 (see FIG. 8C) ) and reaches the base parts of the inclined sections of the protruding parts 36, 37, thereby partially reaching the inclined side section of the first liner 35 (see Fig. 8E) or thereby partially not reaching the inclined side section of the first liner 35 (see Fig. 8D). In this case, the constricted portions 38, 39 accumulate the heat of the molten synthetic resin J.

As a result, the synthetic resin J becomes softer due to the heat accumulated by the constricted portions 38, 39, and therefore the compressed gas G passes over the protruding portions 36, 37 to pass along the “storage tank”, the boundaries of which are determined by the inclined side portions of the protruding portions 36 , 37 and the inclined side portion of the first liner 35. Thus, the compressed gas G will spread throughout the entire “storage tank” (see FIG. 8F). Therefore, the compressed gas G reaching the “storage tank” will allow the synthetic resin J to be forced to push upwardly along the inclined side portion of the first liner 35, since the angle between the inclined side portions of the protruding parts 36, 37 and the inclined side portion the first liner 35 is an approximately right angle, and the synthetic resin from the part where the distance between the flat portion 42 of the upper part of the first liner 35 and the negative part 6 of the mold m flat (insignificant) can be pressed with a uniform density (in Fig. 7, the arrow shows the direction of compression), and thus, uneven transport in the mold and deformation can be prevented even when the molded product is made with a thin-walled part U .

In this case, the compressed gas G located in the cavity S is accumulated in the compression tank 47 through a small gap between the positive part 27 of the mold and the first liner 35 so as not to cause excessive pressure to be applied to the part where the synthetic resin J should be is pressed to the cavity-forming side of the negative mold part 6 by means of compressed gas G. On the other hand, the compressed gas accumulated in the compression tank 47 is supplied to the cavity S through a small gap and through the outlet and inlet channels 48 in order to ensure that the compressed gas will cause the pressing of the unsuccessfully pressed portion. Consequently, the compressed gas will not rise upward along the inclined side portion of the first liner 35, but uniform density can be achieved on the entire periphery of the thin-walled portion U of the molded product, thereby making it possible to manufacture the molded product with a mold configuration.

Then, the compressed gas is injected into the cavity S through gas injection channels 28A, 28B in order to ensure that the synthetic resin is held by pressing the front surface of the synthetic resin J to the cavity forming the negative part 6 of the mold, which is useful for the case of a through hole in the molded product. This will be described below with reference to Fig.9.

That is, as illustrated in FIG. 9, the molten synthetic resin J injected into the cavity S moves over the protruding portion 44 of the upper surface of the positive mold portion 27 by compressing it with compressed gas so that it extends into a groove 54 whose boundaries defined by the protruding part 41 and the protruding part 44, and then reaches the groove 53, the boundaries of which are determined intended to form a through hole part 40B and the protruding part 41 of the second liner 40.

In this case, the compressed gas G accumulates in the compression tank 47 through a small gap between the positive part 27 of the mold and the second liner 40 and the outlet and inlet 49 so as not to cause excessive pressure to be applied to the part where the synthetic resin J can be is pressed to the cavity-forming side of the negative mold part 6 by means of compressed gas G. On the other hand, the compressed gas accumulated in the compression tank 47 is supplied to the cavity S through a small gap and at the outlet and inlet Anal 48 so that it spreads across the unsatisfactorily pinched portion.

As described above, the flow of compressed gas G is temporarily stopped by using the action of the compression tank 47 or by allowing synthetic resin to pass into the grooves 53, 54, thereby allowing compressed gas G to pass to the remaining parts to increase the volume of compressed gas G in the cavity S in in order to ensure exposure, and therefore, the density of the synthetic resin around the through hole of the molded product can be increased. Accordingly, the pressure around the through hole increases due to the preload, and the temperature of the synthetic resin decreases due to the positive part 27 of the mold, the temperature of which has been reduced. Therefore, the synthetic resin is cured, and thus, it is possible to prevent the compressed gas G from rising along the side surface of the through-hole portion 40B of the second liner 40 with it passing around the negative portion 6 of the mold.

As shown in FIG. 6, this embodiment is configured such that the lower surface of the outer peripheral portion of the cavity S is formed by the mold base portion 26 and the mold positive portion 27, protruding portions 30, 31 are formed on the mating portion of the base portion 26 the mold and the positive part 27 of the mold so that they protrude upward in the cavity S, and when the protruding parts 30 and 31 are mated with each other with a partially cut outer side part of the upper portion of the protruding portion 31, the lower portions protruding their parts 30, 31 come into close contact with each other, while their upper portions form a groove 34. However, this embodiment is not limited to the above configuration, but can be made in the form of another embodiment, such as illustrated in figure 10-12.

More precisely, as shown in FIG. 10, the upper surface of the mold base portion 26 at a location adjacent to the positive mold portion 27 is formed with a protruding portion 30A protruding upwardly in the cavity S and having a longitudinal section in the form of a rectangular triangle having an apex angle of, for example, from about 20 to 45 degrees, that is, the protruding part 30A is formed so that each side surface of the mold base part 26 in contact with the corresponding side surface of the positive part 27 is c-shaped, extends upward and further inclined when it extends outward so that the longitudinal plane of the protruding portion 30A has the shape of an approximately right triangle, and the groove 34A, which is part of the cavity S and has a width at which the compressed gas G cannot to enter the groove (for example, a width equal to or less than 0.5 mm) is formed between the positive part 27 of the mold and the protruding part 30A due to partial cutting of the outer side portion of the positive part 27 of the mold from the location at the same level in height as the lower surface of the cavity S (i.e., due to the formation of a stepped part 27A). In this case, the protruding parts 30A, 31A are formed with a rectangular frame shape (string-like shape) in a plan view.

Therefore, the passage of compressed gas around the negative part 6 of the mold, as well as the leakage of compressed gas through the gap between the base part 26 of the mold and the negative part 6 of the mold, can be prevented, since the molten synthetic resin J enters the groove 34A, while the compressed gas can provide satisfactory exposure by pressing the front surface of the synthetic resin to the cavity forming the surface of the negative part 6 of the mold and can cure the molten synthetic resin J for a period of time compression.

In addition, as illustrated in FIG. 11, the protruding portion 30B, which projects upward into the cavity S and whose longitudinal plane is rectangular, is formed on the base portion 26 of the mold at a location adjacent to the positive portion 27 of the mold, then there is a protruding part 30B is formed so that each side surface of the base part 26 of the mold in contact with the corresponding side surface of the positive part 27 of the mold extends upward to form a protruding part 30B having a rectangular longitudinal th plane, and a groove 34B, which is part of the cavity S and has a width at which the compressed gas G cannot enter the groove (for example, a width equal to or less than 0.5 mm), is formed between the positive part 27 of the mold and protruding part 30B due to partial cutting of the outer side portion of the positive part 27 of the mold from a location at the same height level as the lower surface of the cavity S (i.e., due to the formation of a stepped part 27A). In this case, the protruding portion 30B is formed with the shape of a rectangular frame (string-like shape) in a plan view.

Therefore, the passage of compressed gas around the negative part 6 of the mold, as well as the leakage of compressed gas through the gap between the base part 26 of the mold and the negative part 6 of the mold can be prevented, since the molten synthetic resin J enters the groove 34B, while the compressed gas can provide a satisfactory shutter speed by pressing the front surface of the synthetic resin J to the cavity-forming negative part 6 of the mold and can cure the molten synthetic resin J during the compression time period.

In addition, as shown in FIG. 12, the protruding portion 30C that projects upwardly into the cavity S, the longitudinal plane of which is approximately rectangular in shape and whose corner portion, located away from the positive mold portion 27, is blunt, is formed on the base portion 26 the mold in the place adjacent to the positive part 27 of the mold, that is, the protruding part 30C is formed so that each side surface of the base part 26 of the mold in contact with the corresponding side surface of the positive part 27 pres c-shape extends upward, and a groove 34C, which is part of the cavity S and has a width at which the compressed gas G cannot enter the groove (for example, a width equal to or less than 0.5 mm), is formed between the positive part 27 the mold and the protruding part 30C due to partial cutting of the outer side portion of the positive part 27 of the mold from a location at the same height level as the lower surface of the cavity S (i.e. due to the formation of the stepped part 27A). In this case, the protruding portion 30C is formed with the shape of a rectangular frame (string-like shape) in a plan view.

Therefore, the passage of compressed gas around the negative part 6 of the mold, as well as the leakage of compressed gas through the gap between the base part 26 of the mold and the negative part 6 of the mold can be prevented, since the molten synthetic resin J enters the groove 34C, while the compressed gas can provide a satisfactory shutter speed by pressing the front surface of the synthetic resin J to the cavity-forming negative part 6 of the mold and can cure the molten synthetic resin J during the compression time period.

In the case of the formation of a molded product SJ, such as illustrated in FIG. 28, which has a horizontal plane X, a continuous vertical plane Z1 connected to the horizontal plane X at the outer peripheral part of the horizontal plane X in the vertical direction, and a continuous vertical plane Z2 provided on the back the surface of the horizontal plane X, while the vertical plane Z2 has a cylindrical shape or the shape of a rectangular cylinder and is connected to the horizontal plane X in the vertical direction, or in the case of the formation of a molded product without a vertical surface Z1, but with a horizontal surface X and a vertical plane Z2, a technical idea similar to that illustrated in FIGS. 6 and 10-12 can naturally be applied. The above technical idea can also be applied to a similar cavity having a cylindrical space extending in the vertical direction and communicating with the space extending in the horizontal direction in a place located in the middle of the outer peripheral part of the space, since the cavity is not limited in such a configuration that it formed from a space extending in the horizontal direction and a cylindrical space extending in the vertical direction and communicating with the outer peripheral part of the space, but any cavity having such a configuration will be formed from a space extending in the horizontal direction and a cylindrical space extending in the vertical direction and communicating with the space.

In addition, in the case of the formation of a thin-walled part U on the molded product, as illustrated in FIGS. 7 and 8, a configuration is provided in which the first insert 35 is brought into contact with the concave part formed on the upper surface of the positive part 27 of the mold for mounting the first insert 35 on the positive part 27 of the mold; however, the configuration is not necessarily limited to the above, that is, the insert 35 and the positive part 27 of the mold will not be made as separate parts, but they can be made as a single part, as illustrated in FIG. 13, or intended to form a thin wall part 35A may be formed on the positive part 27 of the mold instead of the first insert 35.

An embodiment in which a thin wall portion 35A is formed on the positive mold portion 27 will be described below with reference to FIGS. 13 and 14. First, it should be noted that reference numeral 35A denotes a portion intended for thin wall formation and formed continuously on the upper surface of the positive part 27 of the mold, while the longitudinal plane of part 35A has the shape of an isosceles trapezoid with a shorter upper base and a longer lower base, and is intended for thin wall part 35A is configured so that the distance between the flat surface 42A of the upper part formed on the entire periphery of the upper part for forming the thin wall of part 35A and the negative part 6 of the mold is less than the distance of the remaining parts, which allows formation thin-walled part U on the molded product.

The outer peripheral part and the inner peripheral part of the thin wall forming part 35A are provided with protruding parts 36A, 37A that protrude into the cavity S and are formed with a rectangular frame shape (string-shaped) in plan view and which extend up to a height less than than the height of the flat surface 42A of the upper part, and provided with an inclination when they extend inward, which leads to the fact that in their longitudinal plane they will be formed with the shape of an approximately rectangular triangle alpine, having an angle at the apex, comprising, for example, from about 20 to 45 degrees, and narrowed portions 38A, 39A are formed on their upper portion. In other words, the height of the intersection between the inclined side sections forming the protruding parts 36A, 37A and the inclined side section of the part 35A intended to form a thin wall and having a longitudinal plane with an isosceles trapezoid shape is the same as the height of the lower surface of the cavity S, and the angle formed by both inclined side sections is approximately 90 degrees, that is, approximately a right angle, and the upper portions of the protruding parts 36A, 37A are provided with narrowed parts 38A, 39A, I have good thermal conductivity.

When the compressed gas G is injected into the cavity S through the injection channels 28A, 29A so as to provide a time delay by pressing the front surface of the molten synthetic resin J against the cavity-forming negative part 6 of the mold, the compressed gas G reaches the side surfaces of the protruding parts 36A 37A of a portion 35A intended to form a thin wall so that it contacts the side surfaces, as illustrated in FIG. 14A.

In addition, when the compressed gas G is injected, the compressed gas G reaches the constricted parts 38A, 39A on the protruding parts 36A, 37A (see Fig. 14B), passes over the constricted parts 38A, 39A (see Fig. 14C) and reaches the base parts of the inclined portions of the protruding parts 36A, 37A, thereby partially reaching the inclined side portion of the thin wall portion 35A (see FIG. 14E), or thereby partially not reaching the inclined side portion of the thin wall portion 35A (see fig.14D). In this case, the constricted portions 38A, 39A accumulate the heat of the molten synthetic resin J.

As a result, the synthetic resin J becomes softer due to the heat accumulated by the constricted portions 38A, 39A, and therefore, the compressed gas G passes over the protrusions 36A, 37A to go to the “storage tank", the boundaries of which are determined by the inclined side portions of the protruding parts 36A 37A and the inclined side portion of the thin wall portion 35A, whereby the compressed gas G will spread throughout the “storage tank” (see FIG. 14F).

Therefore, the compressed gas G reaching the “storage tank” will allow the molten synthetic resin J to be forced to push forward the molten synthetic resin upward along the inclined side portion of the thin wall portion 35A, since the angle between the inclined side portions 36A, 37A of the protruding parts 36A, 37A and the inclined side portion of the thin wall portion 35A is approximately a right angle, wherein the compressed gas may ensure proper pressing of the part where the distance between the flat part 42 of the upper portion of the thin wall part 35A and the negative part 6 of the mold is small (insignificant) while the synthetic resin J spreads in this part (in Fig. 13, the arrow shows direction of pressing), and thus, uneven transport in the mold and deformation can be prevented even when a continuous contour having a predetermined width is formed as a thin-walled part U having mu rectangular frame (strunovidnuyu form) at the rear surface side of the molded article. All four sides of the thin-walled portion U may have the same thickness or may have different thicknesses.

As illustrated in FIGS. 7 and 8, this embodiment is configured such that the first insert 35 is brought into contact with the concave portion formed on the upper surface of the positive mold portion 27 when the thin-walled portion U is formed on the molded product. However, this embodiment can be made with a configuration similar to that illustrated in FIG. 15, in which the first insert 35B is brought into contact with the concave portion formed on the upper surface of the positive part 27 of the mold, with the possibility of fastening it to the positive part 27 molds, with this configuration will be described below.

More specifically, in FIG. 15, reference numeral 35B denotes a first insert that is configured so that its continuous contour having a predetermined width is engaged (“connected”) with a rectangular-shaped frame (string-shaped), a concave portion the upper surface of the positive part 27 of the mold with the possibility of fastening the first liner 35B to the positive part 27 of the mold, and the first liner 35B has an upper longitudinal plane with the shape of an isosceles trapezoid having a shorter upper base and a longer lower base has a distance between the flat surface 42B of the upper portion formed on the entire periphery of the upper portion of the first liner 35B and the negative part 6 of the mold, which is smaller than the rest of the parts, and allows the conversion of a continuous contour having a predetermined width in the shape of a rectangular frame (string-shaped), thin-walled part U. All four sides of the thin-walled part U can have the same thickness or can have different thicknesses.

In addition, the lower ends of the inclined side portions of the first liner 35A, the upper part of which is trapezoidal, are higher than the lower surface of the cavity S, and the protruding parts 55, 56 of the indicated lower surface having longitudinal planes with a shorter upper base and a longer lower base, protrude into the cavity S and have a trapezoidal shape with a shorter upper base and a longer lower base (when the inclined sides are elongated, the longitudinal plane will have the shape of approximately a rectangular triangle having an apex angle of, for example, approximately 20 to 45 degrees) and are located at a certain distance (grooves 59A, 59B) from the first liner 35B, while the width of the grooves 59A, 59B is such that the compressed gas G cannot enter inward (e.g. width equal to or less than 0.5 mm) That is, the protruding parts 55, 56 are formed on the upper surface of the positive part 27 of the mold and are located near the first insert 35B.

In addition, the protruding parts 57, 58 are formed in places located at a small distance from the protruding parts 55, 56 formed with the shape of a rectangular frame (string-shaped) in a plan view. The protruding parts 57, 58 extending into the cavity S form the shape of a rectangular frame (string-shaped) in a plan view, have the shape of a right-angled triangle in the longitudinal plane with an apex angle of, for example, from about 20 to 45 degrees, and extend vertically upwardly inclined at the place where they extend towards the first insert 35B. The angle between the inclined side portions of the protruding parts 57, 58 and the inclined side portions of the protruding parts 55, 56 is an almost right angle, i.e. approximately 90 degrees. In this case, the lower surfaces of the grooves 59A, 59B formed between the protruding parts 55, 56 and the first insert 35B are located higher than the lower surface of the cavity S.

In this case, when the compressed gas is injected into the cavity S through channels 28A, 28B for injecting gas in order to ensure a time delay by pressing the front surface of the molten synthetic resin J to the cavity forming the negative part 6 of the mold, the compressed gas first enters contact with the vertical side surfaces of the protruding parts 57, 58. With further injection of the compressed gas, the compressed gas rises up to reach the upper end portions of the protruding parts 57, 58, and then passes over the upper con evymi portions to reach the lower side portions of the inclined bases protruding portions 55, 56 continue to rise up along the inclined side portions of the projecting portions 55, 56.

At this point, the compressed gas rising to the inclined side portions of the protruding parts 55, 56 provides pressure in a direction orthogonal to the inclined side portions of the protruding parts 55, 56, and in a direction orthogonal to the inclined side portions of the protruding parts 57, 58 (see the arrow in FIG. 15), since the angle between the inclined side portions of the protruding parts 55, 56 and the inclined side portions of the protruding parts 57, 58 is approximately a right angle, so that the compressed gas will provide applying pressure in such a way that it will force the molten synthetic resin J to be forced upward along the inclined side portions of the protruding parts 55, 56 and the inclined side portion of the first liner 35B, thereby preventing uneven transfer in the mold and deformation even if when the molded product is provided with a thin-walled part, since sufficient pressure can be applied at a time when the molten synthetic resin J flows before with a small (insignificant) distance between the flat surface 42B of the upper portion of the first insert 35B and the negative part 6 of the mold.

As described above, in the case where the molded product is provided with a thin-walled part, this embodiment is configured such that the thin-walled part, the continuous contour of which having a predetermined width, has the shape of a rectangular frame (string-shaped), formed on the side of the rear surface the molded product by using the first liner 35 as part for forming a thin wall, part 35A, designed to form a thin wall and formed on the positive part 27 mold, and the first insert 35B as part for the formation of a thin wall. However, the thin-walled portion is not limited to the above configuration, but may have an H-shape that is not a continuous frame, may have a cross shape, or may have another shape. In addition, the thin-walled portion formed on the molded product may have the same thickness or may have a different thickness for each straight line.

In addition, this embodiment is not limited to the shape of the protruding portion 41 of the second liner 40 and the shape of the protruding portion 44 formed on the positive portion 27 of the mold, similar to that illustrated in FIG. 9, but may be provided with any other shapes, as illustrated in FIG. .16-18.

First, a configuration similar to that illustrated in FIG. 16 is considered, in which each side surface extends upward on the outer peripheral portion of the upper surface of the fixing portion 40A of the second liner 40, with this surface tilting when it extends adjacent to the forming portion 40B a through hole, as a result of which it is possible to form a protruding part 41A, the longitudinal plane of which has the shape of an approximately rectangular triangle, having angle at the apex, comprising, for example, from about 20 to 45 degrees, and which enters the cavity S, while the protruding part 41A protrudes so that a groove 53A is formed between the part 40B, intended to form a through hole, and the protruding part 41A . The protruding part 44A, formed so that it surrounds the protruding part 41A from the outside, is formed so that each side surface of the positive part 27 of the mold forming the concave part with which the second liner 40 comes into contact extends so that it has an inclination, when it extends outward, it is thus possible that the longitudinal plane will have the shape of an approximately right triangle having an angle at the apex, for example, from about 20 to 45 degrees.

In this case, the protruding part 41A and the protruding part 44A, protruding up to the same height and formed with the shape of a rectangular frame (string-shaped) in a plan view, are formed at the end of each of the upper surfaces of the mating part between the fixing part 40A of the second insert 40 and the positive part 27 of the mold so that they respectively enter the cavity S, the outer side part of the upper portion of the protruding part 44A is partially cut off, and therefore, when the fixing part 40A of the second insert 40 and the positive part 27 ess forms are paired with each other, the lower sections come into tight contact with each other, while the upper sections have a groove 54A having a width at which the compressed gas cannot enter the groove (for example, a width equal to or less than 0, 5 mm). In this case, the depth of the groove 54A formed by the protruding part 41A of the second insert 40 and the protruding part 44A of the positive mold part 27 is made such that it will be slightly less than the depth of the cavity S.

In this case, when the compressed gas is injected into the cavity S through the gas injection channels 28A, 28B to form a through hole in the molded product, the molten synthetic resin J moves over the protruding part 44A of the upper surface of the positive mold part 27 by compressing it by means of the compressed gas to reach the groove 54A formed by the protruding part 44A and the protruding part 41A, and the groove 53A formed by the part 40B for forming the through hole and the protruding part 41A of the second liner 40.

In this case, the compressed gas G located in the cavity S accumulates in the compression tank 47 through a small gap between the positive part 27 of the mold and the second liner 40 and through the outlet and inlet 49 so as not to cause excessive pressure to be applied to the part where the synthetic resin J has to be pressed against the cavity-forming side of the negative mold part 6 by means of compressed gas G. On the other hand, the compressed gas accumulated in the compression tank 47 is supplied to the cavity S through a small the gap in both the outlet and inlet 49 so that the compressed gas can propagate to the part where sufficient pressure is not applied.

As described above, the flow of compressed gas G is temporarily stopped by using the action of the compression tank 47 or by allowing synthetic resin to pass into the grooves 53A, 54A, thereby allowing compressed gas G to pass to the remaining parts to increase the volume of compressed gas G in the cavity S in in order to ensure exposure, and therefore, the density of the synthetic resin around the through hole (open part) of the molded product can be increased. Accordingly, the pressure around the through hole (open part) is increased due to the preload, and the temperature of the synthetic resin is reduced due to the positive part 27 of the mold, the temperature of which has been reduced. Therefore, the synthetic resin is cured, and thus, it is possible to prevent the passage of compressed gas G around the negative portion 6 of the mold, since the compressed gas G rises up along the side surface of the portion 40B of the second liner 40 for forming a through hole.

In addition, as illustrated in FIG. 17, the protruding portion 41B, which has a longitudinal plane with an arcuate shape and enters the cavity S, is formed so that each side surface extends around the outer peripheral part of the upper surface of the fixing part 40A of the second insert 40 with a “passage” »It in a downward direction when approaching part 40B to form a through hole, and as a result of this, a groove 53B is formed between the part 40B intended to form the through hole and the protruding part 41B. The protruding portion 44B, formed so that it surrounds the protruding portion 41B from the outside, is configured so that each side surface of the positive mold portion 27 forming the concave portion receiving the second liner 40 extends so that its height decreases as as it passes outward, thereby ensuring that the longitudinal plane will have an arcuate shape.

In this case, the protruding part 41B and the protruding part 44B, which protrude up to the same height so that they respectively enter the cavity S, are formed with the shape of a rectangular frame (string-like shape) in a plan view at the end of each upper surface of the mating part between the fixing part 40A of the second liner 40 and the positive mold part 27, and the outer side portion of the upper portion of the protruding portion 44B is partially cut off, and therefore, when the fixing part 40A of the second liner 40 and the positive mold part 27 s are interconnected, the lower portions of their protruding parts come into close contact with each other, while the upper portions form a groove 54B having a width at which compressed gas G cannot enter the groove (for example, a width equal to or less than 0.5 mm). In this case, the depth of the groove 54B formed by the protruding part 41B of the second insert 40 and the protruding part 44B of the positive mold part 27 is made such that it will be slightly less than the depth of the cavity S.

In this case, when the compressed gas is injected into the cavity S through the gas injection channels 28A, 28B to form a through hole in the molded product, the molten resin J moves over the protruding portion 44B of the upper surface of the positive mold part 27 by supplying it by means of compressed gas in order to reach the groove 5BA formed by the protruding part 44B and the protruding part 41B and the groove 53B formed by the part 40B for forming the through hole and the protruding part 41B of the second insert 40.

In this case, the compressed gas G located in the cavity S is accumulated in the compression tank 47 through a small gap between the positive part 27 of the mold and the second liner 40 and through the outlet and inlet 49 so as not to cause excessive pressure, larger than necessary, to the part where the synthetic resin J must be pressed against the cavity forming side of the negative mold part 6 by means of compressed gas G. On the other hand, the compressed gas accumulated in the compression tank 47 give into the cavity S through a small gap and on the output and input channel 49 so as to enable the underpressure of the under-pressed part by means of compressed gas.

As described above, the flow of compressed gas G is temporarily stopped by using the action of the compression tank 47 or by allowing synthetic resin to pass into grooves 53B, 54B, thereby allowing the compressed gas G to spread widely to the remaining parts to increase the volume of compressed gas G in the cavity S to ensure the holding of the synthetic resin, and therefore, the density of the synthetic resin around the through hole of the molded product can be increased. Accordingly, the pressure around the through hole (open part) is increased due to the preload, and the temperature of the synthetic resin is reduced due to the positive part 27 of the mold, the temperature of which has been reduced. Therefore, the synthetic resin is cured, and thus, it is possible to prevent the passage of compressed gas G around the negative portion 6 of the mold, since the compressed gas G rises up along the side surface of the portion 40B of the second liner 40 for forming a through hole.

In addition, as illustrated in FIG. 18, the protruding portion 41C, which has a longitudinal plane with the shape of an approximately rectangular triangle having an apex angle of, for example, approximately 20 to 45 degrees, and extends into the cavity S, is formed so that each side surface extends around the outer peripheral part of the upper surface of the fixing part 40A of the second liner 40 with an inclination in the area where it extends near the part 40B to form a through hole, and as a result, the groove 53 40B is formed between the part intended to form the through hole, and the protruding portion 41C formed to the shape of a rectangular frame (strunovidnoy shape) in plan view.

When the compressed gas G is injected into the cavity S through the injection channels 28A, 28B to form a through hole in the molded product, the molten synthetic resin J is in contact with the protruding portion 41C of the second liner 40 due to the pressure applied by the compressed gas, thereby preventing the passage of synthetic resin J around the negative part 6 of the mold.

More precisely, especially when the second liner 40, as a part for forming a through hole, is located far from the gas injection channels 28A, 28B, if the volume of compressed gas G in the cavity S increases to increase the density of the synthetic resin J, i.e., if the compressed gas G can ensure that pressure is applied up to the area around the second liner 40, the protrusion on the positive part 27 of the mold is eliminated, and as a result, the passage of synthetic resin around the negative part can be prevented 6 of the mold only by the protruding portion 41C of the second liner 40.

However, as described above, it is necessary that the compressed gas G located in the cavity S accumulates in the compression tank 47 through a small gap between the positive part 27 of the mold and the second liner 40 so as not to cause excessive pressure, larger than necessary, to the part where the synthetic resin J must be pressed to the cavity forming side of the negative mold part 6 by means of compressed gas G, and, on the other hand, it is necessary to supply compressed gas accumulated in the compression m reservoir 47 into the cavity S through the small gap so as to allow propagation of the compressed gas in preloaded insufficient portion.

The above embodiment shows, as an example, the formation of a molded product, the cavity S of which is in the form of a box-shaped top cover (having a rectangular horizontal surface and four vertical surfaces extending in the vertical direction downward from each side of the horizontal surface). Another embodiment of the formation of a plate-shaped molded product will be described below with reference to Fig.19-22.

First, the insert 65, having the shape of an approximately rectangular parallelepiped, is brought into contact with the concave part formed on the positive part 27 of the mold, with the possibility of mounting on it, and a cavity S is formed, the boundaries of which are determined by the negative part 6 of the mold, the insert 65 and positive part of 27 mold. The upper surface of the liner 65 is slightly smaller than the lower surface of the cavity S, that is, the lower surface of the cavity S is formed by a part of the peripheral edge portion of the hole on the upper surface of the positive mold part 27 and the liner 65. In addition, each side surface extends upward on the outer peripheral part the upper surface of the liner 65 with its inclination when it extends inward, thereby providing the possibility of the formation of the protruding part 60, the longitudinal plane of which is approximately straight an angular triangle having an angle at the apex, comprising, for example, from about 20 to 45 degrees, and which enters the cavity S, protruding into it, and which is formed with the shape of a rectangular frame (string-like shape) in the plan view [in the plane], as a result of which a groove 61 is formed having a width at which the compressed gas G cannot enter the groove (for example, a width equal to or less than 0.5 mm) between the negative mold part 6 and the protruding part 60. The protruding part 44A, formed so that it surrounds the protruding part 4 1A is externally formed so that each side surface of the positive portion 27 of the mold forming the concave portion with which the second liner 40 comes into contact extends so that it slopes as it extends, thereby making it possible that the longitudinal plane will be in the form of an approximately rectangular triangle having an apex angle of, for example, approximately 20 to 45 degrees.

However, as described above, it is not always necessary to perform the protruding part 60 on the entire outer peripheral part of the upper surface of the liner 65 or to form a groove 61 over the entire interval between the protruding part 60 and the negative part 6 of the mold, but they can be partially performed on the outer peripheral portion of the horizontal part of the molded product, where the compressed gas is characterized by a tendency to spread easily everywhere, the purpose of the protruding part 60 and the groove 61 is to prevent the passage of compressed gas and around the front surface of the negative part 6 of the mold. More precisely, they can be performed only in those areas (in those areas) where compressed gas can leak from the injection molding equipment when the compressed gas passes around the front surface of the negative part 6 of the mold.

When compressed gas from the source of compressed gas is supplied to the cavity S through the feed valve and through the channel 28C for injecting gas after injection of a predetermined amount of molten synthetic resin J into the cavity S, a layer forms between the molten synthetic resin J injected into the cavity S and the liner 65 compressed gas (see Fig.21).

In addition, with further injection of the compressed gas, the molten synthetic resin J reaches the peripheral part of the cavity S, while it moves through the inclined portion of the protruding part 60 and enters the groove 61. Accordingly, the compressed gas escapes outward because the molten synthetic resin J has entered into the groove 61, and therefore, the passage of compressed gas around the front surface of the negative part 6 of the mold is prevented (see FIG. 22).

In this case, the compressed gas G located in the cavity S is accumulated in the compression tank 47 through a small gap between the positive part 27 of the mold and the liner 65 and through the outlet and inlet channel 67 so as not to cause excessive pressure than necessary, to the part where the synthetic resin J is to be pressed against the cavity-forming side of the negative mold part 6 by means of compressed gas G. On the other hand, the compressed gas accumulated in the compression tank 47 is supplied to olost S via a small gap and on the output and input port 67 so that compressed gas can spread to a part in which not enough pressure is applied. Accordingly, the passage of compressed gas around the negative mold part 6 and its leakage out of the injection molding equipment through the gap between the negative mold part 6 and the positive mold part 27 can be prevented, and the compressed gas can provide a sufficient delay time by pressing the front surface of the synthetic resin to the cavity forming the negative part 6 of the mold.

In the above embodiment, a case of forming a plate-like molded product is described in which the protruding portion 60 extending into the cavity S protrudes from the outer peripheral portion 60 of the upper surface of the liner 65 and the groove 61 is formed between the negative portion 6 of the mold and the protruding portion 60. Another embodiment the implementation of the formation of the molded product, the cavity S of which is in the form of a box-shaped top cover (having a rectangular horizontal surface and four vertical surfaces, a strike schiesya vertically downwardly from the horizontal surface of each side) and in which can be the greatest extent possible prevented from leaking compressed gas will be described below with reference to fig.23-26.

First, the insert 66, having the shape of an approximately rectangular parallelepiped, is brought into contact with the concave part formed on the positive part 27 of the mold, with the possibility of mounting on it, a cavity S is formed, the boundaries of which are determined by the negative part 6 of the mold, the insert 66 and the positive part 27 of the mold, and the lower surface of the cavity S will be formed by the liner 66 and the positive part 27 of the mold.

More specifically, the protruding portion 62 is formed so that it extends upward at a location within a small distance inside with respect to the outer peripheral end portion of the upper surface of the liner 66 and tilted when it “approaches” the inner side so that to ensure that its longitudinal plane will have the shape of an approximately rectangular triangle having an angle at the apex, for example, from about 20 to 45 degrees, while the angle at the apex “enters” into the cavity S. Crom moreover, each side surface extends upwardly at the peripheral edge part of the hole formed on the upper surface of the positive part 27 of the mold, forming the concave part of the positive part 27 of the mold to form a concave part, and in this case, the protruding part 63 is formed on the positive part 27 of the mold so that it has a slope when it "approaches" its outer side, while the protruding portion 63 enters the cavity S and has a longitudinal plane with the shape of an approximately rectangular triangle having its apex angle, for example, from about 20 to 45 degrees. In this case, the protruding part 63 is formed with a greater height than the protruding part 62, and a groove 64 having a width at which the compressed gas G cannot enter the groove (for example, a width equal to or less than 0.5 mm) is formed between the protruding part 62 of the insert 66 and the protruding part 63 of the positive part 27 of the mold. The protruding parts 62, 63 are formed with the shape of a continuous rectangular frame (string-shaped) in a plan view, which, however, is not limiting, but the protruding parts 62, 63 can be formed not continuous and can be provided only in the area where the compressed gas may spread to the front surface of the positive portion 27 of the mold, which would cause the compressed gas to leak outward from the injection molding equipment.

When a predetermined amount of the molten synthetic resin J is injected into the cavity S, the molten synthetic resin J moves through the inclined side portion of the protruding portion 60 to partially enter the groove 64 (see FIG. 24), and then when the compressed gas is supplied to cavity S from the source of compressed gas through the feed valve and through the channel 28D for injecting gas between the molten synthetic resin J injected into the cavity S and the liner 66 forms a layer of compressed gas (see Fig.25).

In addition, when injecting compressed gas, the compressed gas reaches the upper portion of the protruding portion 62 of the liner 66; however, since the protruding portion 63 of the positive mold portion 27 is located higher than the protruding portion 62 of the liner 66, the compressed gas can provide pressure without “passing” through the protruding portion 63 (see FIGS. 26 and 27).

In other words, as described above, since the protruding part 63 of the positive part 27 of the mold is higher than the protruding part 62 of the insert 66, the molten synthetic resin J entering the groove 64 will not separate from the molten synthetic resin J not entering the groove 64, even while holding the synthetic resin J by means of compressed gas. Accordingly, if the molten synthetic resin J separates, the compressed gas may pass over the protruding portions 62, 63 and exit to the front surface of the positive mold portion 27, resulting in leakage of the compressed gas to the outside of the injection molding equipment. However, with the above configuration, it is possible to prevent the compressed gas from escaping outward, and the compressed gas can provide sufficient shutter speed so that the molten synthetic resin J can be cured during the period of time when the molten synthetic resin J is compressed by the compressed gas.

The present invention has been described with reference to embodiments; however, a person skilled in the art can make various alternatives, changes and modifications without departing from the spirit and scope of the invention. The present invention should be construed as encompassing the various alternatives described above, changes and modifications made without departing from the essence and scope of the invention.

Claims (15)

1. A method of injection molding, in which molten synthetic resin is injected into a cavity formed between the negative part of the mold and the positive part of the mold, for molding it, which includes operations in which
heating the side of the negative part of the mold provided with the cavity forming surface by supplying a coolant to the channel of the negative part of the mold intended for the coolant to initiate an increase in temperature of the side with the cavity forming surface;
injecting a predetermined amount of molten synthetic resin into the cavity after stopping the temperature increase;
injecting compressed gas into the space between the rear side of the synthetic resin and the cavity-forming surface of the positive mold part after injection of the molten synthetic resin to provide a time delay by pressing the front surface of the synthetic resin to the cavity-forming surface of the negative mold part; and
curing the synthetic resin on the side of the negative part of the mold provided with the cavity forming surface by supplying a coolant to the channel of the negative part of the mold intended for the coolant while providing a time delay by means of compressed gas. 2. The injection molding method according to claim 1, further comprising an operation in which
injecting cooling gas into the space between the rear surface of the synthetic resin and the cavity forming the surface of the positive part of the mold after displacing the compressed gas from the injection molding equipment when the synthetic resin is cured to a certain extent. 3. The injection molding method according to claim 1, wherein the compressed gas injected into the cavity is trapped in the reservoir through the space between the part intended to form a thin wall and the positive part of the mold so as not to cause excessive compression in more than necessary, in the part where the synthetic resin can be pressed against the cavity forming the surface of the negative part of the mold, when the part for forming a thin wall, designed to form a thin-walled part on the molded product and formed in the concave portion formed on the upper surface of the positive mold part, wherein the compressed gas collected in the tank are simultaneously fed to the portion where is not provided sufficient compressed gas compression. 4. The injection molding method according to claim 1, in which the compressed gas injected into the cavity is captured in the reservoir through the space between the part intended to form the hole and the positive part of the mold so as not to cause excessive compression in a larger degrees than necessary, in the part where the synthetic resin can be pressed against the cavity forming the surface of the negative part of the mold, when the part for forming a hole, intended to form a part with a hole in the molded product, is made the vapor in the concave portion formed on the upper surface of the positive portion of the mold, wherein the compressed gas collected in the reservoir is simultaneously supplied to the portion where sufficient compression of the compressed gas is not provided. 5. Equipment for injection molding, which is configured to allow injection of molten synthetic resin into the cavity formed between the negative part of the mold and the positive part of the mold, for molding it,
in which the channel intended for the coolant is located so that it passes along the cavity, which allows the coolant or coolant to pass into it; and
in which the channels for pumping gas are configured to supply compressed gas into the cavity, while
heating the side of the negative part of the mold provided with the cavity forming surface by supplying a coolant to the channel of the negative part of the mold intended for the coolant to initiate an increase in temperature of the side with the cavity forming surface,
injecting a predetermined amount of molten synthetic resin into the cavity after stopping the temperature increase;
injecting compressed gas into the space between the rear side of the synthetic resin and the cavity-forming surface of the positive mold part after injection of the molten synthetic resin to provide a time delay by pressing the front surface of the synthetic resin to the cavity-forming surface of the negative mold part; and
curing the synthetic resin on the side of the negative part of the mold provided with the cavity forming surface by supplying a coolant to the channel of the negative part of the mold intended for the coolant while providing a time delay by means of compressed gas. 6. Equipment for injection molding, which is configured to enable injection of molten synthetic resin into the cavity formed between the negative part of the mold and the positive part of the mold, after heating the side of the negative part of the mold provided with the cavity forming surface, injecting compressed gas into the space between the rear surface of the synthetic resin and the cavity-forming surface of the positive part of the mold and providing a time delay by pressing the front surface of the synthetic resin to the cavity-forming surface of the negative part of the mold, in which the lower surface of the cylindrical part of the cavity formed from a space extending in the horizontal direction and a cylindrical space that is continuous with respect to this space and extends in the vertical direction, formed from the base of the mold and the positive portion of the mold to be attached to the concave portion formed on the base of the mold rmy; and in which the protruding part, protruding upward so that it enters the cavity, is formed at each end portion of the upper surface of the mating part between the base part of the mold and the positive part of the mold so that it is formed with the shape of the frame along the mating part, and both protruding parts form a groove in the upper part when both protruding parts are mated with each other. 7. Equipment for injection molding, which is configured to enable injection of molten synthetic resin into the cavity formed between the negative part of the mold and the positive part of the mold, after heating the side of the negative part of the mold provided with the cavity forming surface, injecting compressed gas into the space between the rear surface of the synthetic resin and the cavity-forming surface of the positive part of the mold and providing a time delay by pressing the front surface of the synthetic resin to the cavity-forming surface of the negative part of the mold, in which the lower surface of the cylindrical part of the cavity formed from a space extending in the horizontal direction and a cylindrical space that is continuous with respect to this space and extends in the vertical direction, formed from the base of the mold to which the positive part of the mold is attached; and
in which the protruding part, protruding upward so that it enters the cavity, is formed along the mating part so that it is formed with the shape of a frame at the end portion of the upper surface of the base part of the mold at the part mating with the positive part of the mold, and a groove is formed between the protruding part and the positive part of the mold. 8. Equipment for injection molding, which is configured to enable injection of molten synthetic resin into the cavity formed between the negative part of the mold and the positive part of the mold, after heating the side of the negative part of the mold provided with the cavity forming surface, injecting compressed gas into the space between the rear surface of the synthetic resin and the cavity-forming surface of the positive part of the mold and providing a time delay by pressing the front surface of the synthetic resin to the cavity-forming surface of the negative part of the mold, in which the liner, the upper part of which enters the cavity and the longitudinal plane of the upper part of which has a trapezoidal shape, has a shorter upper base and a longer lower base, and which forms a thin-walled a part on the molded product is brought into contact with a concave part formed on the upper surface of the positive part of the mold, with the possibility of fixing on it; and
in which a protruding portion having an inclined side portion that is approximately orthogonal to the inclined side portion of the liner is formed on the upper surface of the liner so that it enters the cavity. 9. Equipment for injection molding, which is configured to allow injection of molten synthetic resin into the cavity formed between the negative part of the mold and the positive part of the mold, after heating the side of the negative part of the mold provided with the cavity forming surface, injecting compressed gas into the space between the rear surface of the synthetic resin and the cavity-forming surface of the positive part of the mold and providing a time delay by pressing the front surface of the synthetic resin to the cavity cavity forming the negative part of the mold, in which the part intended to form a thin wall, the longitudinal plane of the upper portion of which has a trapezoidal shape, having a shorter upper base and a longer lower base, and which forms a thin-walled part on molded product, formed in the form of a protrusion on the upper surface of the positive part of the mold so as to allow entry of the upper portion of the protrusion into the floor spine; and in which the protruding portion having an inclined side portion approximately orthogonal to the inclined side portion of the portion intended to form a thin wall is formed on the upper surface of the portion intended to form a thin wall such that the protruding portion enters the cavity. 10. Equipment for injection molding according to any one of paragraphs.8 or 9, in which the narrowed part is made on the upper section of each of the protruding parts. 11. Equipment for injection molding, which is configured to enable injection of molten synthetic resin into the cavity formed between the negative part of the mold and the positive part of the mold, after heating the side of the negative part of the mold provided with the cavity forming surface, injecting compressed gas into the space between the rear surface of the synthetic resin and the cavity-forming surface of the positive part of the mold and providing a time delay by pressing the front surface of the synthetic resin to the cavity-forming surface of the negative part of the mold, in which the liner, the upper part of which enters the cavity and the longitudinal plane of the upper part of which is trapezoidal, having a shorter upper base and a longer lower base, is brought into contact with the concave part formed on the upper surface of the positive part of the mold, with the possibility of fixing on it; in which the first protruding part entering the cavity is formed on the upper surface of the positive part of the mold located next to the liner; and
in which the second protruding part having an inclined side portion approximately orthogonal to the inclined side portion of the first protruding portion is formed on the upper surface of the positive portion of the mold so that the second protruding portion enters the cavity. 12. Equipment for injection molding, which is configured to enable injection of molten synthetic resin into the cavity formed between the negative part of the mold and the positive part of the mold, after heating the side of the negative part of the mold provided with the cavity forming surface, injecting compressed gas into the space between the rear surface of the synthetic resin and the cavity-forming surface of the positive part of the mold and providing a time delay by pressing the front surface of the synthetic resin to the cavity-forming surface of the negative part of the mold, in which the liner, which enters the cavity and the upper part of which comes into contact with the negative part of the mold to form a part with a hole in the molded product, is brought into contact with the concave a part located on the upper surface of the positive part of the mold, with the possibility of fixing on it; and
in which the protruding part entering the cavity is formed on the outer peripheral part of the liner, and a groove is also formed between the protruding part and the outer peripheral part. 13. Equipment for injection molding, which is configured to enable injection of molten synthetic resin into the cavity formed between the negative part of the mold and the positive part of the mold, after heating the side of the negative part of the mold provided with the cavity forming surface, injecting compressed gas into the space between the rear surface of the synthetic resin and the cavity-forming surface of the positive part of the mold and providing a time delay by urging the front surface of the synthetic resin to the cavity forming surface portion of a negative mold,
in which the liner, which enters the cavity and the upper part of which comes into contact with the negative part of the mold to form part with a hole in the molded product, is brought into contact with the concave part formed on the upper surface of the positive part of the mold, with the possibility of fixing on her;
in which the first protruding part entering the cavity is formed on the outer peripheral part of the liner, and a groove is also formed between the first protruding part and the outer peripheral part;
in which the second protruding part entering the cavity is formed on the upper surface of the positive part of the mold so that it surrounds the first protruding part from the outside; and in which a groove is formed between the second protruding part and the first protruding part. 14. Equipment for injection molding, which is configured to enable injection of molten synthetic resin into the cavity formed between the negative part of the mold and the positive part of the mold, after heating the side of the negative part of the mold provided with the cavity forming surface, injection of compressed gas into the space between the rear surface of the synthetic resin and the cavity-forming surface of the positive part of the mold and providing a time delay by m pressing the front surface of the synthetic resin to the cavity forming the surface of the negative part of the mold, in which the liner is brought into contact with the concave part formed on the upper surface of the positive part of the mold, with the possibility of fixing on it; and
in which the protruding part entering the cavity is made on the upper surface of the liner, and a groove is also formed between the protruding part and the side surface defining the boundaries of the cavity of the negative part of the mold. 15. Equipment for injection molding, which is configured to allow injection of molten synthetic resin into the cavity formed between the negative part of the mold and the positive part of the mold, after heating the side of the negative part of the mold provided with the cavity forming surface, injecting compressed gas into the space between the rear surface of the synthetic resin and the cavity-forming surface of the positive part of the mold and providing a time delay by urging the front surface of the synthetic resin to the cavity forming surface portion of the negative mold, wherein the liner is brought into contact with the concave portion formed on the upper surface of the positive mold part, to be fixed on it;
in which the first protruding part entering the cavity is formed on the upper surface of the liner, and the second protruding part entering the cavity is formed on the peripheral edge part of the hole on the upper surface of the positive part of the mold with a concave part, the second protruding part protruding on greater height than the first protruding part; moreover, a groove is formed between the second protruding part and the first protruding part.

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