JPH08258100A - Injection molding method and mold for execution thereof - Google Patents

Abstract

PURPOSE: To prevent generation of no good appearance such as flow marks, uneven gloss and jetting at the surface of a molded part, and generation of uneven wall thickness and so on. CONSTITUTION: By bringing the ends of a plurality of control pins 5 in/out of a mold cavity 4, injection molding is carried out while controlling flowing direction, flowing speed and pressure distribution inside the cavity of injected resin. It is desirable that the ends of a plurality of control pins 5a, 5b should be selectively-brought in and out with the passage of time. This can be applied to injection compression molding, injection stamping, hollow injection molding and so on in addition to ordinary injection molding. It is thus possible to variably-adjust the flowing condition and pressure distribution of the injected resin 17 in the cavity 4 by the operation of the control pin 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding method and a mold apparatus for carrying out the method, and more specifically, an injection molding method using a thermoplastic resin, an injection compression molding method, or various skin materials. Injecting thermoplastic resin into the mold using injection molding machine, such as injection stamping molding method that decorates and integrates thermoplastic resin with thermoplastic resin at the same time, and hollow injection molding method that injects inert gas into thermoplastic resin In this case, by controlling the flow direction and speed of the resin in the mold, the weld position on the surface of the molded product can be changed, the flow marks can be eliminated, and the appearance of the molded product can be improved. A new injection molding method capable of hollowing a desired portion by controlling the flow diffusion direction of an inert gas injected into a thermoplastic resin, and an injection molding die suitable for the implementation thereof Provide equipment It is intended.

[0002]

2. Description of the Related Art Generally, thermoplastic resins have been used in a wide range of fields such as automobile parts, home electric appliance parts, OA equipment parts, furniture parts, and building material parts due to their good moldability, dimensional stability of molded products, and good appearance. There is. These various parts are divided into exterior parts and interior parts or structural parts, and are manufactured by a molding method centered on an injection molding method from the viewpoint of productivity and economy.

Generally, a molded product has a wall thickness of 1.5 to 3.0 mm.
A normal injection molding method is used in which a thermoplastic resin is pressure-filled in a mold of a desired shape before and after by injection molding, but a molded product having a relatively large area, various sheets on the surface, In the case of decorative integral molding with cloths, an injection compression molding method (Japanese Patent Laid-Open No. 61-137713, Japanese Patent Laid-Open No. 6-137713).
No. 1-137714, etc.), injection stamping molding method (JP-A-5-169485, Japanese Patent Application No. 5-220094).
No.) has been used. In addition, in order to prevent warpage of molded products, to prevent sinking of molded products with a wall thickness of 3.0 mm or more, and to reduce the weight, a similar injection molding machine is used to inject an inert gas into the plasticized thermoplastic resin. Injection molding methods (Japanese Patent Publication No. 48-41264, Japanese Patent Publication No. 57-14968, etc.) have also been used in recent years.

In various molding methods centering on these injection molding methods, since a plasticized thermoplastic resin is filled into a target mold to obtain a molded product, the flow direction and speed of the resin in the mold are It has greatly affected the appearance of molded products.
However, when the shape of the mold is determined, there is only a method for controlling the multi-stage filling speed by an injection molding machine for the flow direction and speed of the resin during filling in the mold, which causes various problems in the appearance of the molded product. Hereinafter, problems in various injection molding methods will be described.

In the general injection molding method, once the shape of the mold is determined, the flow velocity and direction of the thermoplastic resin in the mold at the time of molding are mainly controlled by the following method. That is, regarding the flow rate, changing the fluidity of the thermoplastic resin itself, changing the plasticization temperature in the molding machine,
Alternatively, the flow rate of the resin in the mold is adjusted by controlling the injection speed in multiple stages using the function of the injection molding machine. However, these are all controls of the resin in a plasticized state before entering the mold, and it has not been possible to accurately control the actual behavior of the resin in the mold.

On the other hand, with respect to the flow direction, it is generally practiced to provide a rib having a wall thickness so as to guide the resin in the mold and change the direction of the resin in the mold along the rib. I could hardly control it. Therefore, where there is a change in wall thickness or where the flow path changes abruptly, flow marks, uneven gloss, and other appearance defects occur, and the place where the resin-to-resin joint is called weld is also uncontrollable.
There were many problems in terms of appearance and physical properties of the molded product.
Therefore, there has conventionally been a demand for a method of accurately controlling the flow velocity, the direction, the resin pressure, etc. of the resin in the mold to solve these problems.

Further, when a thick-walled molded product having a wall thickness of 3.0 mm or more is molded by a normal injection molding method, the thermoplastic resin injected into the mold is a resin having a small diameter from a resin gate having a wide space. Since it is discharged into the mold cavity, the resin at the time of injection is solidified in a string shape in the vicinity of the gate, which causes a so-called jetting appearance defect in which the surface of the molded product exhibits a meandering pattern. Therefore, generally, the resin gate position is provided so as to hit the cavity surface so that the thermoplastic resin injected into the mold does not directly jump out into the space inside the mold cavity, or just before entering the cavity. To prevent jetting, the runner part of the is enlarged in stages. However, the position of the resin gate and the size of the gate diameter become a big problem in a product in which the appearance of the molded product is important, and therefore many restrictions are imposed on the mold design. Therefore, there has been a demand for a molding method capable of obtaining a thick-walled molded product having a good appearance without jetting without providing restrictions on the mold design such as changing the resin gate position and diameter.

Furthermore, an injection compression molding method used for manufacturing a molded product having a wide area and requiring a uniform wall thickness, and a molded product which is not susceptible to warp deformation due to residual stress after molding,
In an injection stamping molding method in which various skin materials and a thermoplastic resin are integrally molded, the resin is injected in a state where the mold is open, and then the resin is uniformly compressed and filled on the projection surface by the mold clamping, and a predetermined amount is obtained. Shape the shape. In these methods, the shape of the supplied resin spreads concentrically from the resin gate, and even at the compression shaping stage by mold clamping, the resin flow that expands concentrically fills the resin to the end of the mold. For this reason, the resin first reaches a position near the resin gate even in the periphery of the molded product, the pressure in this part rises, and the excess resin flowing in this direction is sequentially distributed to the peripheral part far from the resin gate. Then, the part farthest from the gate is filled and the shaping is completed. Therefore, the filling pressure is high in the peripheral portion where the resin first reaches and is low in the portion where the resin finally reaches, and this pressure difference slightly corresponds to the change in the wall thickness when a molded product having a uniform wall thickness is obtained.

On the other hand, in the integral decorative molding method of the skin material and the thermoplastic resin, the peripheral portion, which is close to the resin gate in the distance and first reaches the resin, is used for the decoration by the increase of the resin pressure due to the compression. The thermoplastic resin leaks through the skin material,
On the other hand, the portion far from the gate and arriving at the end is not fully filled with the resin, so that it is easy to become unfilled called short shot. To solve such problems, increase the number of gates for resin supply, shorten the flow distance from the gates, and, like the injection molding method, provide thick ribs on the molded product toward the peripheral part that is difficult to fill and flow. By giving the role of a leader, the resin filling speed to the peripheral end is adjusted. However, if the number of gates is increased, it is difficult to balance the resin supply amount of each gate, and the resin supply is apt to be biased, and the runner portion remaining in the molded product is also increased, which is complicated. on the other hand,
Even if a thick rib is provided on the molded product to give it the role of a flow leader, unlike the injection molding method in which the resin is filled into the closed mold, the last step of closing the mold in injection compression and injection stamping. At the time of several mm, the resin only slightly moves in the rib portion for the first time, and has little role as a flow leader. In this way, after the resin is supplied into the mold by the injection compression molding method or the injection stamping molding method, the supplied resin is preferentially guided to the peripheral portion farther than the gate until shaping by mold clamping, When shaping the final mold, the resin is filled in the peripheral part of the molded product in a substantially uniform time regardless of the distance from the gate, and the resin pressure in the mold is such that the resin pressure in the peripheral part is almost uniform. There was a need for a method that could control the speed.

Furthermore, even in the hollow injection molding method in which an inert gas is injected into the plasticized resin by an injection molding method using a thermoplastic resin, appearance defects such as uneven gloss and flow marks on the surface of the molded product are observed. Was a big problem. That is, in the hollow injection molding method, during or after the injection of the plasticized thermoplastic resin into the mold, generally, an inert gas such as nitrogen gas is injected along the flow direction of the resin, The resin being filled is accelerated by gas pressure, and the skin layer once cooled and solidified is moved to the mold surface, or the moving speed in the mold of the resin flow front end is significantly changed,
The appearance defects of molded products, which are called flow marks and uneven gloss, occur remarkably. For this reason, in TV cabinets and automobile interior parts where appearance is important, the surface of the molded product is painted,
The mold surface is made into a product by making fine defects or specific irregularities called pearskin finish or specific irregularities on the mold surface in advance (Japanese Patent Laid-Open No. 3-216325) to make defects inconspicuous. However, after molding,
The method of concealing appearance defects by painting requires separate pre-treatment, painting, and solvent removal painting steps, which requires a large amount of capital investment, as well as an increase in the period and a defective rate due to painting, resulting in product yield. Also remarkably decreases, which is not preferable. Further, the method of making unevenness on the surface of the mold to make the surface of the molded product skin-textured or satin-finished did not completely eliminate flow marks and uneven gloss, and was not sufficient for improving the appearance of the molded product. in this way,
Even in the hollow injection molding method in which an inert gas is injected into the thermoplastic resin, there has been a demand for a molding method that gives a molded article a good surface appearance.

Furthermore, regarding the hollowing of a product having a relatively large wall thickness by the hollow injection molding method, when the inert gas was injected by the usual injection molding method, the injected inert gas was plasticized. Since the thermoplastic resin penetrates in the direction with the least resistance, the shape of the hollow portion changes under a slight molding condition and becomes different for each molding, and it is difficult to hollow the target portion. To eliminate this,
In recent years, a so-called core-back gas injection molding method for injecting a mold of a hollow portion into a mold in which a thermoplastic resin is injected, and then opening the mold in accordance with an injection amount of an inert gas to uniformly make the hollow (Japanese Patent Laid-Open No. 4-2128).
No. 22, JP-A-4-255314 and others) have been proposed and put to practical use. In this method, although it is possible to stably obtain a hollow surface of the mold, which is a target, it is necessary to provide a mechanism for moving a part of the mold by a predetermined amount. The appearance of the molded product on the surface deteriorates. Therefore, there is a need for a method that injects an inert gas as close as possible to a general injection molding method, and surely guides the flow direction of the injected inert gas in the same direction for each molding, so that stable production is possible. Was there.

[0012]

SUMMARY OF THE INVENTION In the present invention, an injection molding machine such as an injection molding method using a thermoplastic resin, an injection compression molding method, or a hollow injection molding method of injecting an inert gas into the thermoplastic resin is used. When injecting a thermoplastic resin into a mold to manufacture a resin molded product, solve the problems of poor appearance such as flow marks, uneven gloss, jetting, etc. that occur on the surface of the molded product, and improve the appearance or strength. An object is to move the position of occurrence of a weld portion having a problem above to an arbitrary place.

Further, in the present invention, in the injection compression molding method or the injection stamping molding method which is a decorative integral molding method of various skin materials and thermoplastic resin, the thermoplastic resin supplied into the mold is shaped. Solves the problem of uneven pressure distribution that causes unevenness in wall thickness due to the difference in arrival time and pressure difference between the peripheral portion near the supply port and the peripheral portion farthest from the supply port, and resin leakage through the skin material. This is also an issue. Another object is to guide the inert gas injected in the hollow injection molding method in an arbitrary flow direction.

[0014]

SUMMARY OF THE INVENTION The present invention relates to the conventional resin acceleration by ribs or the like regarding the flow direction, speed adjustment and pressure adjustment of the resin in the mold in various injection molding methods using thermoplastic resin. The present invention relates to a novel injection molding method and an apparatus for carrying out the same, which achieves the above-mentioned object by using a control pin that obstructs the flow of a resin based on a completely opposite idea.

That is, the injection molding method according to the present invention controls the flow direction, flow velocity, and pressure distribution of the injected resin in the cavity by moving the tips of the plurality of control pins into and out of the mold cavity. It is characterized by performing injection molding while performing.

Normally, the tips of the plurality of control pins are selectively pulled in and out over time. Further, the plurality of control pins are arranged so that an equal-pressure line substantially parallel to the peripheral edge of the cavity is formed inside the resin that has entered a region near the peripheral edge in the cavity during resin injection or mold clamping. However, there are also cases where the taking in and out is controlled. This method is used when injection compression molding is performed by clamping the mold after resin injection, injection stamping molding in which the skin material and the thermoplastic resin are integrally molded, or when the injection resin inside the cavity is filled. It can also be applied when hollow injection molding is performed by injecting gas. When performing hollow injection molding, the diffusion direction of the injected gas can also be controlled by the plurality of control pins.

The injection molding die apparatus according to the present invention, which is suitable for carrying out the above-described method according to the present invention, has a plurality of control pins provided so that its tip can be inserted into and removed from the mold cavity, and a plurality of control pins. And a drive control device capable of controlling the control pin to be taken in and out. It is recommended that the drive control device be configured so that the tips of the plurality of control pins can be selectively taken in and out with time. While the resin is injected or the mold is clamped, the plurality of control pins are arranged inside the resin that has entered a region close to the peripheral edge of the cavity so that isobars substantially parallel to the peripheral edge of the cavity are formed. It is recommended to provide a drive control device that controls the access.

After injection of the resin, the mold is clamped to perform injection compression molding, or injection stamping molding is performed in which the skin material and the thermoplastic resin are integrally molded, or the injection into the cavity is performed. In some cases, a gas injection port for injecting gas is provided inside the resin to perform hollow injection molding. In the case of hollow injection molding, it is recommended that the plurality of control pins also control the diffusion direction of the injected gas.

The control pin provided in the present invention is provided on the upstream side or the downstream side of the defective appearance portion of the molded product in the process of filling the mold with the thermoplastic resin injected from the gate in the mold cavity. The present invention provides a novel injection molding method for controlling the flow rate and direction of a plasticized resin and the diffusion direction of an inert gas injected into a thermoplastic resin.

It is recommended that the control pin of the present invention is installed in the mold cavity, which is the back surface opposite to the front surface where the appearance of the molded product is emphasized. Here, it is recommended that the diameter of the control pin be small for small molded products and thin molded products, and thick for large molded products and thick molded products, generally 1.0 to 1
0.0 mm is suitable. If the diameter is 1.0 mm or less, the effect of cooling the resin by the pin and the flow inhibition effect is small,
If it is 0.0 mm or more, the resin flow inhibiting effect is too large to perform delicate control. Therefore, a particularly preferable pin diameter is about 3.0 mm or more and 8.0 mm or less. However, since there is a marked difference in the resin flow in the mold depending on the shape, wall thickness, and size of the molded product, it is not limited to the above pin diameter and it is possible to change it to the optimum diameter as necessary. The cross section is not limited to a circle, but may be an ellipse or a droplet type. The height of the control pin of the present invention is recommended to be 1/4 or more and 2/3 or less of the thickness of the molded product. When the height of the pin of the present invention is 1/4 or less of the wall thickness of the molded product, the effect of inhibiting the resin flow in the mold is small, and when it is 2/3 or more of the wall thickness of the molded product,
On the contrary, a resin flow pattern due to pins is generated on the surface of the molded product, resulting in poor appearance. Therefore, the preferable pin height is preferably 1/3 or more and 1/2 or less of the thickness of the molded product. The number of control pins of the present invention installed so as to hinder the flow of the thermoplastic resin in the mold cavity is not particularly limited, and it may be set at a plurality of positions according to the shape of the molded product and the purpose. It is possible.

Among the appearance defects caused by injection molding, in order to eliminate flow marks, gloss unevenness, etc., the thermoplastic resin injected from the resin gate undergoes a sudden change in the flow direction,
The movable control pin of the present invention is provided on the resin flow path in the mold cavity that reaches the location where the wall thickness changes rapidly and the flow velocity changes rapidly. Using this mold, when the thermoplastic resin injected from the gate reaches the control pin, or during or after passing through the control pin, the pin is retracted to completely fill the resin in the mold. That is, when the thermoplastic resin injected from the resin gate gradually fills the mold cavity as a diffusive flow, the control pin of the present invention provided in the cavity causes resistance and cooling of the thermoplastic resin. The flow is obstructed by being entangled with the pin, and the resin flow in that direction is suppressed, but the resin flow in the other directions is accelerated. After the resin flow in the peripheral portion other than the vicinity of the control pin is accelerated for a certain period of time, by retracting the control pin of the present invention from the cavity, the flow in the original pin direction is also delayed from the time and recovered from the surroundings, Finally, the mold is filled up to the end of the mold, and a trace of the resin flow regulated by the control pin does not appear in the molded product, so that a molded product having a good appearance can be obtained.

Further, in order to eliminate the appearance defect called jetting, which appears when a thick-walled molded product is manufactured by the injection molding method, the movable control pin of the present invention is similarly used for the resin in the mold cavity. It is recommended to install it just before the gate. That is, in order to prevent the plasticized thermoplastic resin from scattering from the gate into the mold cavity, the resin injected into the control pin of the present invention provided in front of the gate is struck, and after a certain time, near the gate. When is filled with the lump of injected resin and there is no fear of resin scattering, the tip of the control pin is retracted to the mold cavity surface. After that, a thermoplastic resin is filled up to the end of the mold cavity to obtain a thick-walled molded product having an excellent surface appearance without jetting.

Further, in the case of manufacturing a molded article having an opening by an injection molding method or injecting a resin from a multi-point gate, the position change of the weld line caused by the association of the resins can be changed. This is possible by providing the control pin in the mold cavity. That is, the control pin of the present invention is provided at a desired location on one side of the location where the resins are associated with each other by the resin flow in the normal mold cavity. As a result, when the resin is filled by injection molding, the resin flow from one side is suppressed by this control pin, while the resin flow on the other side advances and flows into the vicinity of the control pin. At this stage, the position of the weld line can be changed to a desired position by appropriately retracting the control pin to the same surface as the mold cavity surface and filling the cavity with resin.

On the other hand, in the injection compression molding method and the injection stamping molding method, the thermoplastic resin is injected into the mold cavity at the stage where the mold is not completely closed, and the resin is compressed in the mold by the mold clamping. To fill. Here, the movable control pin of the present invention can be arranged in the mold cavity in order to fill the resin around the molded product in a substantially uniform time regardless of the resin gate position for supplying the resin. That is, the control pin is provided between the resin gate and the closest peripheral portion, and is provided at a plurality of places such as between the control gate and the next closest peripheral portion. When the resin injected into the mold through the control pins provided at these plural positions flows by compression due to mold clamping and spreads in the mold cavity, the resin is entangled with the control pins of the present invention from the resin gate. The operation is performed such that the control pin provided at the farthest place is sequentially withdrawn from the control pin provided near the gate in stages. That is, when viewed from the mold projection surface, the shape of the supplied thermoplastic resin gradually changes from a concentric shape centered on the resin gate to a reduced similarity shape of the molded product projection surface and a projection surface shape. , So that the control pin can be withdrawn according to the tightening. In this way, the injection compression molding method and the injection stamping molding method make the resin filling time around the flow end of the mold cavity almost the same, so that the resin from the mold or the skin material due to the partial resin pressure difference Leakage and partial difference in wall thickness are eliminated, and a resin molded product having a good surface appearance and a uniform wall thickness can be obtained.

Flow mark in the hollow injection molding method,
These problems can be solved by using the flow control pin of the present invention even for the appearance defect called uneven gloss. In the hollow injection molding method, an inert gas such as nitrogen gas is injected into the plasticized thermoplastic resin that is injected or is being injected into the mold cavity. Therefore, the thermoplastic resin moving in the mold cavity is partially accelerated and significantly decelerated at the flow end to be filled. Here, in the mold cavity, one or more flow regulating pins of the present invention are provided at a plurality of positions perpendicular to the flow direction of the resin from the resin gate to the flow end. When the resin is injected from the resin gate and the inert gas is injected inside and moves in the mold cavity, the resin reaches the control pins one by one, and when the resin is entangled, it is sequentially retracted from the pin closer to the gate, The resin flow rate in the mold due to gas injection is suppressed. By providing the control pin of the present invention in the mold cavity in this way, the appearance defects such as flow marks and uneven gloss, which were problems in the hollow injection molding method, are eliminated, and a hollow injection molded product having an excellent surface appearance. Can be obtained.

Further, in the hollow injection molding method, the control pin of the present invention can be used for controlling the flow direction of the injected inert gas when the molded product having a relatively large wall thickness is made highly hollow. The inert gas injected by the hollow injection molding method penetrates in the direction of the least resistance in the resin during filling in the mold. Therefore, due to changes in molding conditions, the inflow direction of the injected inert gas changes every time, and it is difficult to stably introduce the inert gas into a target portion. Therefore, the inert gas can be introduced in a desired direction by installing the control pin of the present invention in the mold cavity at an appropriate position in the direction where it is desired to prevent gas diffusion from the gas injection port. The diameter of the control pin that regulates the inert gas is generally 0.5 mm to 10.0 mm. When the diameter is 0.5 mm or less, the effect of inhibiting the resin from cooling and flow by the pin is small, and when the diameter is 10.0 mm or more, the effect of inhibiting the resin flow is too large and delicate control cannot be performed. Therefore,
Particularly preferable control pin diameter is 1.0 mm or more and 5.0 mm
It is about the following. However, since there is a marked difference in the resin flow in the mold depending on the shape, wall thickness, and size of the molded product, it is not limited to the above pin diameter, and it is possible to change it to an appropriate diameter as necessary. However, the cross section is not limited to a circular shape, and may be an oval shape, a droplet shape, or the like.

The height of the gas control pin of the present invention is recommended to be 1/4 or more and 2/3 or less of the wall thickness of the molded product. When the height of the pin of the present invention is 1/4 or less of the wall thickness of the molded product, the effect of inhibiting the resin flow in the mold is small, and 2/3 of the wall thickness of the molded product is obtained.
In the above, the flow pattern of the resin due to the control pin is generated on the surface of the molded product, resulting in poor appearance. Therefore, the preferable pin height is preferably 1/3 or more and 1/2 or less of the thickness of the molded product. The number of control pins of the present invention installed so as to inhibit the flow of the inert gas in the mold cavity is not particularly limited, and a plurality of control pins can be installed at a plurality of positions depending on the shape of the molded product and the purpose. Therefore, it is recommended to use a movable type especially when the appearance of the molded product is emphasized.

Examples of the thermoplastic resin used in the molding method of the present invention include polystyrene resin, ABS resin, low-density polyethylene resin, high-density polyethylene resin, polypropylene resin, vinyl chloride resin and other general-purpose resins.
Alternatively, polyamide resin, polycarbonate resin, PB
There are T resins, polyacetal resins, and other engineering resins, and polymer alloys of these resins and various elastomers are also included. Further, glass fibers, talc, mica, etc. may be blended with these resins, or a plasticizer,
It also includes a thermoplastic resin composition in which a release agent, an antistatic agent and other various additives are blended, and a coloring agent such as a pigment or a dye is kneaded.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings. First, the outline of each drawing will be described.
FIG. 1 is a partially sectional enlarged perspective view of an outer case of a business-use telephone manufactured by a conventional injection molding method, showing a state in which a flow mark is generated on the downstream surface of the opening. FIG. 2 is an explanatory view showing the positions where the control pins according to the present invention are provided in order to prevent the generation of flow marks in the injection molding of the outer case of the business-use telephone shown in FIG. FIG. 3 is a cross-sectional view showing an embodiment of a mold device provided with a control pin according to the present invention in order to prevent the generation of flow marks, and the flow velocity of the resin on the downstream side is gradually increased by the control pin. It is suppressed and the opening of the molded product is filled at a low speed, and the generation of flow marks is eliminated.

FIG. 4 is a cross-sectional view showing an embodiment of a mold device provided with a control pin according to the present invention in order to prevent uneven gloss on the front surface side of a molded product having a mounting hook portion on the back surface.

FIG. 5 is a simulated view of a T-shaped armrest of an office chair as an example of a thick-walled molded product that easily causes jetting. FIG. 6 is a cross-sectional view showing an embodiment of a mold device provided with a control pin according to the present invention in order to prevent jetting of a wall-thickness molded product as shown in FIG. A control pin is provided nearby, and injection resin is made to collide with this control pin once to collect it, and then the control pin is retracted to fill the resin into the cavity to prevent jetting. is there. FIG. 7 is an explanatory diagram showing the positional relationship between the control pin and the filling resin shown in FIG.

FIG. 8 is an external view of a molded product of a container cover in which a weld is generated in the ring portion of the mounting hole provided in the corner portion. FIG. 9 is an external view of a molded product of a container cover in which a weld is generated on the main body side by the injection molding method of the present invention, in which a control pin according to the present invention is provided in a mold for molding the container cover. The state where the flow direction of the resin in the mold is changed and the weld generation position is moved from the ring portion of the mounting hole to the main body side is shown.

FIG. 10 is a partial cross sectional simulated view of an automobile interior console lid as an example of an integrally molded product of a skin material and a resin by injection stamping molding. FIG. 11 is a cross-sectional view showing an embodiment of an injection stamping molding die device according to the present invention, which is provided at a specific position in a die cavity by driving hydraulic cylinders mounted above and below the die. The control pin of the present invention can be operated. In the figure, the resin is injected in the half-open state of the mold, and the state immediately before the start of compression shaping by mold clamping is shown. FIG. 12 is a view showing the state of resin filling viewed from the direction of the projection surface during normal injection stamping molding over time, and the resin filling into the mold cavity is
It shows a state where the resin gate is concentrically expanded. FIG. 13 is a view showing a resin filling state as seen from a projection surface direction at the time of injection stamping molding provided with a control pin according to the present invention with time. By retracting the control pin provided nearby and then retracting the control pins provided near the left and right long sides, the pressure distribution of the resin in the cavity forms an isobar that is substantially parallel to the peripheral edge of the cavity. , The resin spreads in a shape similar to the projection projection plane.

FIG. 14 is a sectional view showing an embodiment of a hollow injection molding die apparatus according to the present invention for preventing the generation of flow marks in hollow injection molding. A hydraulic cylinder attached to the upper portion of the die. By controlling the flow of the resin by the gas in the mold by sequentially retracting the control pins provided along the resin flow direction in the mold cavity by driving the In the figure, the resin in which gas is injected reaches the position of the first control pin. FIG. 15 is an external view showing a state where a vehicle molding as an example of a molded product having a hollow portion on the back side is manufactured by ordinary hollow injection molding, and a flow mark is generated on the surface thereof. FIG. 16 is an external view showing a state in which a similar vehicle molding is manufactured by hollow injection molding provided with a control pin according to the present invention and has no flow mark on its surface.

FIG. 17 is a horizontal cross-sectional perspective view of a thick-walled box-shaped product manufactured by ordinary hollow injection molding, showing that an amoebar-shaped hollow portion is generated in the thick-walled molded product. FIG.
8 is a horizontal cross-sectional perspective view showing a state in which a similar thick-box-formed product is manufactured by hollow injection molding provided with a control pin according to the present invention, and the hollow portion is formed in a constant shape so as to avoid the control pin. Is.

[Embodiment 1] FIG. 1 shows a dimension width of 180 m.
m x length 220 mm x height 15 mm, wall thickness 2.0 mm,
FIG. 1 is a partially enlarged cross-sectional perspective view of a commercial telephone outer case 1 having a weight of about 110 g / piece, in which 11 is a resin flow direction, 12 is a surface of a molded product, 13 is a cross section of the molded product, 1
Reference numeral 4 denotes an opening slit in the speaker mounting portion.

In order to manufacture such an outer case for a telephone for business use, in the test mold apparatus according to the present invention, as shown in FIG. 2, the opening slit 14 of the speaker mounting portion is formed from the resin gate 16 thereof. In the last position,
Four movable control pins 5 having a height of 0.8 mm and a diameter of 3.0 mm were provided at 5 mm intervals, and a flow mark elimination test was performed. As shown in FIG. 3, the operation of these control pins is performed by the air cylinder 6 attached to the fixed-side mold 2 of the mold device including the fixed-side mold 2 and the moving-side mold 3, and an injection start signal is sent. Accordingly, a sequence circuit (not shown) for activating the air cylinder 6 by a timer is provided. Reference numeral 17 in FIG. 3 indicates a thermoplastic resin in the filling process. This test mold was attached to an injection molding machine (M-200AII: manufactured by Meiki Seisakusho Co., Ltd.) with a clamping force of 200 t, and ABS resin (Santac U was used as a thermoplastic resin).
T-61: manufactured by Mitsui Toatsu Chemical Co., Ltd.).

First, the control pin 5 is retracted without protruding into the mold cavity to be in the same state as a conventional mold having no control pin, and the resin temperature 240 of the molding machine is set.
℃, mold temperature 50 ℃, injection time 2.0 seconds, cooling time 2
A trial production was carried out under a molding condition of 5.0 seconds. As a result,
As shown in FIG. 5, the generation of the flow mark 15 was recognized on the downstream side of the opening slit 14 when viewed from the mold resin gate 16 side.

Next, according to the present invention, injection is started in a state where the tip of the control pin 5 is projected into the cavity 4, and when 0.8 seconds has passed after the start of injection, it is the same as the mold cavity surface. A timer was set so that the control pin could be retracted to the surface, and other molding conditions were the same as above, and trial production was performed.
As a result, no flow mark was found around the opening slit 14, and a molded product having a good appearance was obtained. This is because the flow velocity of the resin on the downstream side is gradually suppressed by the control pin 5, and the opening slit portion of the molded product is filled at a low speed, thereby eliminating the generation of the flow mark.

Example 2 Next, in order to manufacture a pillar for automobile interior having dimensions of width 78 mm × length 575 mm, wall thickness 2.5 mm, and weight of about 151 g / piece, practical use as shown in FIG. Using a mold device, height 1.0 from the resin gate immediately before the slide core, which is the hook for attaching the back surface.
Two movable control pins 5 having a diameter of 3.0 mm and a diameter of 3.0 mm were provided at intervals of 5 mm, and a gloss unevenness elimination test was performed. The operation of the control pin 5 is performed by the air cylinder 6 provided in the mold 2, and a sequence circuit is provided so that the timer can be operated according to the injection start signal. This modified practical mold device was attached to an injection molding machine (N400BII: manufactured by Japan Steel Works, Ltd.) with a clamping force of 400t, and polypropylene resin (Mitsui Noblen BJHH: manufactured by Mitsui Toatsu Kagaku Co., Ltd.) was used as a thermoplastic resin. A molded product was manufactured using.

First, the control pin 5 is retracted into the mold cavity 4 without protruding, and the resin temperature 2 of the molding machine is set in the same state as the conventional mold having no control pin.
Molding was performed under the molding conditions of 30 ° C., mold temperature of 50 ° C., injection time of 2.2 seconds, and cooling time of 20.0 seconds. As a result, in the front side grain surface of the pillar molded product, in the area where the hook part is on the back side, the grain surface is partially glossy, and when the entire product is viewed from the front, poor appearance called gloss unevenness occurs. did.

Next, according to the present invention, with the control pin 5 protruding into the mold cavity, 1.3 from the start of injection.
Set the timer to retract the control pin after a second,
Other trials were performed under the same molding conditions as above. As a result, no gloss was found on the front side grain surface corresponding to the hook portion, and a molded product having a good appearance without uneven gloss was obtained.

[Embodiment 3] As shown in FIG. 5, the size of the rising portion from the resin gate 16 is width 58 mm × height 280 mm, wall thickness about 30.5 mm, and weight about 800 g.
In order to manufacture a T-shaped armrest of 1 / office chair, a practical mold apparatus according to the present invention as shown in FIG. 6 was produced. That is, the resin gate 16 in the mold cavity (dimension 12 m
(m × 5mm) 8.0mm forward, to prevent scattering of the resin supplied from the gate, 3 movable control pins 5 with a height of 20.0mm and a diameter of 6.0mmφ at 3.0mm intervals. A jetting elimination test was conducted. The operation of the control pin is performed by the air cylinder 6 provided on the mold 3, and a sequence circuit is provided so that the timer can be operated in response to the injection start signal. This modified practical mold device was attached to an injection molding machine (IS450FA2: manufactured by Toshiba Machine Co., Ltd.) with a mold clamping force of 450t, and a polypropylene resin (Mitsui Noblen BJHH: manufactured by Mitsui Toatsu Chemical Co., Ltd.) was used as a thermoplastic resin. A foaming agent was blended to produce a molded product.

First, the control pin 5 is retracted into the mold cavity 4 without protruding, and the resin temperature 2 of the molding machine is set in the same state as the conventional mold having no control pin.
A molded product was manufactured under the molding conditions of 20 ° C., mold temperature 40 ° C., injection time 8.5 seconds, and cooling time 180 seconds. As a result, an appearance defect called jetting occurred on the surface of the molded product near the gate and on the side opposite to the gate.

Next, with the three control pins 5 protruding into the mold cavity 4, the three control pins 5
The positional relationship between the resin and the filling resin is shown in FIG. ), A timer was set to withdraw the control pin 2.0 seconds after the start of injection, and other molding conditions were the same as before, and a molding trial was performed. As a result, no jetting was observed near the gate or on the surface of the molded product on the side opposite to the gate, and it was possible to manufacture a T-shaped armrest for an office chair having a good appearance.
This is a result of the resin injected from the gate 16 being once collided with the control pin 5 and collected, and then the control pin is retracted to fill the cavity with resin.

[Embodiment 4] Next, as shown in FIG.
Molded product dimensions width 200 mm x length 150 mm x height 10 m
A rectangular container cover having a thickness of 3 mm and a thickness of 3 mm and a weight of about 96 g / piece, and 3.2 on the outside of the four corners.
A weld position change test was performed using a test mold for producing a container cover having a ring portion with a mounting hole of 18 mmφ with a width of mm. That is, as shown in FIG. 9, the ring holes of the mounting holes provided outside the four corners on the mold core side and the rectangular cover body are connected to each other at a position closer to the center resin gate 16. 1.5m in height so as to block the flow of resin from the gate to each connection
Two movable control pins 5 each having a diameter of 5.0 mm and a diameter of 5.0 mm were provided at 3.0 mm intervals. The operation of this pin is performed by an air cylinder provided inside the mold, and a sequence circuit that can operate a timer in response to an injection start signal is provided. This modified test die was used as an injection molding machine (M-
200AII: Attached to Meiki Seisakusho Co., Ltd. and used as a thermoplastic resin polypropylene resin (Mitsui Noblene BJ
HM-T: manufactured by Mitsui Toatsu Chemical Co., Ltd.).

First, the control pin 5 is retracted without protruding into the mold cavity, and in a state similar to a conventional mold having no control pin, the resin temperature 22 of the molding machine is set.
0 ℃, mold temperature 50 ℃, injection time 1.5 seconds, cooling time 1
It was manufactured under the molding condition of 4.0 seconds. As a result, FIG.
As shown in FIG. 3, a weld 18 was formed in the ring portion of the mounting hole on the outer periphery of the container cover which is a molded product. Since this part is tightened by inserting a screw or the like into the mounting hole, the weld 18
If there is, it is easily broken and is not preferable.

Then, next, the control pin 5 is made to protrude into the mold cavity, a timer is set so that the control pin can be withdrawn 1.0 seconds after the start of injection, and other molding conditions are the same as before. And made a prototype. As a result, no weld was generated in the ring portion of the mounting hole on the outer periphery of the container cover, and it was generated in the weld 18 behind the control pin 5 when viewed from the resin gate 16 on the container cover body side. Thus, by moving the weld generation position from the ring portion to the container cover body side, even if the ring portion is fixed with a screw or the like, no damage occurs.

[Embodiment 5] As shown in FIG. 10, in the case of manufacturing an automobile interior console lid 20 having a width of 120 mm, a length of 240 mm, a height of 32 mm, a thickness of 3.0 mm and a weight of about 282 g / piece. explain. The thermoplastic resin layer 13 is formed by injection stamping molding.
It is manufactured by integrally decorating the outer skin material 21 on the outside of the.

In order to manufacture the automobile interior console lid 20 as such a decorative integrally molded product, a test mold as shown in FIG. 11 was prepared. That is, the movable control pin 5 according to the present invention is provided on the core side mold 2 of the test mold shown in FIG.
A and 5b were provided, and a confirmation test was carried out so that the resin was uniformly and simultaneously filled into the peripheral edge of the mold during injection stamping molding. In the mold core portion, five control pins 5b each having a diameter of 5.0 mm and a height of 2.0 mm are provided between the resin gate 16 and the two long sides closest to the central portion of the rectangle as viewed from the projection surface. Between the two shortest sides farthest from the resin gate, the diameter is 5.0 mmφ and the height is 2.0 mm in the central part near the short sides.
The control pins 5a of 3 are provided for each of the three. When the tips of these control pins are moved in and out of the mold cavity, the springs 51 and 53 acting to retract the control pins 5a and 5b and the control pins are pushed out against the spring forces. A drive device which is configured to include rods 52 and 54 which hold and hold the inner end of the control pin to be fitted therein, and hydraulic cylinders 61 and 62 which drive the rods up and down, respectively, and a sequence circuit for controlling the drive device ( (Not shown in the figure) and drive control is performed.

That is, at the start of resin injection, the rods 52 and 54 are kept at a fixed position so that the tips of the control pins 5a and 5b are projected into the cavity as shown in the figure, and predetermined from the start of injection. After a predetermined time elapses, the hydraulic cylinder 61 is first driven by the command signal from the sequence circuit to move the rod 52 downward, so that the inner end of the control pin 5a is fitted into the recessed portion of the rod 52 and the spring 51 acts. The control pin 5a retracts, and after a lapse of a predetermined time, the hydraulic cylinder 62 is driven to move the rod 54 downward so that the inner end of the control pin 5b fits into the recessed portion of the rod 54 and the spring 53 acts to control the pin 5b. The drive can be controlled to retract. The mold is an injection molding machine (N40
OBII: manufactured by Japan Steel Works Ltd., a moquette cloth with 2.5 mm urethane foam attached to the back side is used as the decorative skin material 21, and polypropylene resin (Mitsui Noblene BJ4H: Mitsui) is used as the thermoplastic resin. Using Toatsu Kagaku Co., Ltd.), injection stamping molding was performed at a plasticizing resin temperature of 200 ° C. and a mold temperature of 40 ° C., and the resin filling time around the molded product was examined.

First, the control pins 5a and 5b are retracted without protruding into the mold cavity, and in the same state as in the conventional mold having no control pin, the skin material 21
Was set on the mold cavity surface so that the back side of the mold faced the mold core side, the mold was closed at a low speed, and a prescribed amount of resin was injected in a half-opened condition with the skin material sandwiched. After 1.2 seconds, the remaining mold was closed, and compression was performed to produce an integrally molded product of the skin material and the resin. In this case, the time course of filling the thermoplastic resin 17 into the cavity 4 spreads concentrically from here around the resin gate 16 as shown in FIG. 12, and as a result, the resin gate 16 At the edge that is closest to, and along the long sides where the resin first reaches,
The thermoplastic resin leaked through the moquette of the skin material, while the unfilled portion 41 of the cavity remained near both short sides farthest from the resin gate 16, resulting in a short shot.

Next, as shown in FIG. 13, with the tips of the control pins 5a and 5b according to the present invention projected into the mold cavity, the other molding conditions are the same as before, and the prescribed amount of resin is used. When the mold is closed and compressed in 1.2 seconds after that, 0.8 seconds after starting the mold clamping, first retract the control pins 5a near both short sides into the cavity surface (shown by 5a '), After 1.0 second, the control pin 5b near both long sides was retracted (indicated by 5b ') by timer control to perform compression integral molding. As a result, resin leakage did not occur in the outer peripheral portion of the skin material moquette, and the resin filling state on the back surface of the skin material was uniform and a good molded product was obtained. As described above, the control pins 5a and 5b are controlled so as to be retracted with a time lag so that the pressure distribution in the cavity of the injected resin during the resin injection and the mold clamping can be adjusted to the peripheral portion of the cavity. This is because it is adjusted so as to form an isobar which is substantially parallel to.

[Embodiment 6] A width of 3 as shown in FIG.
8 mm x length 800 mm, wall thickness 2.5 mm, width 12 mm x length 800 mm, wall thickness 8 mm rib in the center of the back surface in the longitudinal direction, and the weight of about 128 g / by hollowing the inside of the rib with an inert gas. Using a practical mold for manufacturing individual vehicle moldings 101, the following modifications were carried out for the purpose of eliminating flow marks generated on the surface of the molded product during hollow molding. That is, as shown in FIG. 14, it is a vehicle molding practical type having a resin gate 16 and an injection port 32 of a gas injection pin 31 at one end in the longitudinal direction, and the cavity surface of the back rib portion has a diameter of 7.5 mmφ and a height of 4. 0 mm movable control pin 5
c ~ 5g from the resin gate to the flow end 30mm, 5
It was provided at positions of 0 mm, 60 mm, and 65 mm. As the drive mechanism for these control pins, as in the embodiment shown in FIG. 11, a spring 51, a rod 52, and a hydraulic cylinder 61 are used, and control is performed by a sequence circuit that operates a fixed time after receiving an injection signal. I decided to do it. An injection molding machine (PZ65) having a mold clamping force of 650 t, which is equipped with a gas compression injection device (manufactured by Battenfeld [Ltd.]), is attached to this mold.
0SA: Attached to Ube Industries, Ltd.) and used as a thermoplastic resin for polypropylene resin (Mitsui Noblene BJHH:
Mitsui Toatsu Kagaku Co., Ltd.), using nitrogen gas as an inert gas, a hollow injection molded product was manufactured under the following molding conditions.

First, the control pins 5c to 5g are retracted without protruding into the mold cavity, and the resin temperature 22 is set in the same state as the conventional mold having no control pin.
Hollow molding at 0 ° C, mold temperature of 50 ° C, injection time of 3.5 seconds, nitrogen gas was injected from 2.0 seconds after the injection was started, and the gas pressure was gradually increased to a maximum of 120 kg / cm ^2. I made a product. As a result, as shown in FIG. 15, a flow mark 1 showing a resin flow pattern on the surface of the molding product.
5 occurred.

Next, while the control pins 5c to 5g according to the present invention are projected into the mold cavity, molding is carried out under the same molding conditions as described above, and the control pins 5c to 5g are installed at the position closest to the resin gate 16. From the control pin 5c present to the pin 5g close to the flow end, it was operated so as to be sequentially withdrawn from 2.6 seconds after the start of injection. As a result, the resin flow velocity in the mold was suppressed by the control pin, and as shown in FIG. 16, no flow mark was generated on the surface of the molding product 102, and a hollow molding product having a good appearance was obtained.

[Embodiment 7] As shown in FIGS. 17 and 18, a thick hollow molded product 103 having a width 90 mm × a length 120 mm × a thickness 5 mm having a resin gate 16 and a gas injection port 32 in the central portion was prepared. Using the test mold to be manufactured, the following molding was carried out in order to confirm the intrusion of the injected gas and the control of the diffusion direction. First, this mold was attached to an injection molding machine (M-200AII: manufactured by Meiki Seisakusho Co., Ltd.) with a mold clamping force of 200t equipped with a gas compression injection device (manufactured by Mitsui Toatsu Chemicals, Inc.),
Polypropylene resin (Mitsui Noblen JHH-G: manufactured by Mitsui Toatsu Chemicals, Inc.) is used as the thermoplastic resin, nitrogen gas is used as the inert gas, and the resin temperature is 220 ° C. and the mold temperature is 50.
A hollow molded article was produced at a temperature of 80 ° C. and a gas pressure of 80 kg / cm ² . As a result, the nitrogen gas that has entered the molded product 103 is
It spreads like an amoebar, the hollow shape inside the molded product changed with each molding, and a uniform product could not be made.

Next, as viewed from the projection surface, the cavity portion of this mold has a radius 20 centered on the resin gate 16 at the center.
At the intersection of the circle of mm and the diagonal line of the four corners, diameter 3.0 mm
The control pin 5 according to the present invention having φ and a height of 2.5 mm was attached so that it could be taken in and out. This mold was attached to a molding machine in the same manner as above, and a hollow molded product was manufactured under the same molding conditions. As a result, the nitrogen gas that has penetrated into the molded product does not penetrate into the back side of the control pin 5, but penetrates and diffuses in a regular form between the control pins, and a stable and uniform hollow shape is obtained in each molding. Was given.

[0059]

As described above, by using the molding method of the present invention, an injection molding method using a thermoplastic resin, an injection compression molding method, or a hollow injection molding method in which an inert gas is injected into the thermoplastic resin. For example, when injecting resin into the mold using an injection molding machine to produce a molded product, it eliminates appearance defects such as flow marks, uneven gloss, and jetting that occur on the surface of the molded product, It is possible to move the position where the weld, which has a problem in strength and strength, to an arbitrary position. Further, in the injection compression molding method or the injection stamping molding method for performing decorative integral molding of various skin materials and the thermoplastic resin, the thermoplastic resin supplied into the mold by applying the molding method of the present invention. It is possible to obtain a uniform molded product in which the resin arrival time to the peripheral part of the mold is made uniform at the time of molding, there is no resin leakage from the peripheral part of the skin material, and there is no peripheral wall thickness and pressure difference. .

Further, by applying the molding method of the present invention to the hollow injection molding method, it becomes possible to arbitrarily determine the invasion and diffusion directions of the inert gas injected into the resin, and molding having a stable hollow shape. You can get the goods. Therefore, the present invention is applicable to all of these various injection molding methods, and by using the injection molding die apparatus according to the present invention which is particularly suitable for carrying out the method of the present invention, The appearance can be improved,
A uniform, high-quality molded product can be manufactured, and the molded product can be widely used for various purposes of manufacturing a resin molded product.

The present invention is not limited to the above embodiment, and for example, the control pin loading / unloading drive mechanism is
The springs 51 and 5 not necessarily shown in FIG. 11 and FIG.
The present invention is not limited to 3, rods 52, 54, etc., and can be replaced by other appropriate means capable of achieving the same action, and other components can be appropriately designed and modified within the scope of the object of the present invention. Therefore, the present invention covers all modifications that can be easily conceived by those skilled in the art from the above description.

[Brief description of drawings]

FIG. 1 is a partially sectional enlarged perspective view of an outer case of a business-use telephone manufactured by a conventional injection molding method.

FIG. 2 is a view for preventing the generation of flow marks in the injection molding of the outer case of the business phone shown in FIG.
It is explanatory drawing which shows the position which provides the control pin by this invention.

FIG. 3 is a view for preventing a flow mark from being generated.
It is sectional drawing which shows one Example of the metal mold | die apparatus provided with the control pin by this invention.

FIG. 4 is a cross-sectional view showing an embodiment of a mold device provided with a control pin according to the present invention in order to prevent uneven gloss on the front surface side of a molded product having a mounting hook portion on the back surface.

FIG. 5 is a simulated view of a T-shaped armrest of an office chair as an example of a thick molded product that easily causes jetting.

FIG. 6 is a cross-sectional view showing an embodiment of a mold device provided with a control pin according to the present invention in order to prevent jetting of the wall-thickness molded product as shown in FIG.

FIG. 7 is an explanatory diagram showing a positional relationship between the control pin and the filling resin shown in FIG.

FIG. 8 is an external view of a molded product of a container cover in which a weld has occurred in a ring portion of a mounting hole provided in a corner portion.

FIG. 9 is an external view of a molded product of a container cover in which a weld is generated on the main body side by the injection molding method of the present invention.

FIG. 10 is a partial cross-sectional simulated view of an automobile interior console lid as an example of an integrally molded product of a skin material and a resin by injection stamping molding.

FIG. 11 is a sectional view showing an embodiment of an injection stamping molding die device according to the present invention.

FIG. 12 is a view showing a resin filling state as seen from a projection surface direction during normal injection stamping molding over time.

FIG. 13 is a view showing a resin filling state as seen from a projection surface direction at the time of injection stamping molding provided with a control pin according to the present invention with time.

FIG. 14 is a cross-sectional view showing an example of a hollow injection molding die device according to the present invention for preventing the generation of flow marks in hollow injection molding.

FIG. 15 is an external view showing a state where a vehicle molding as an example of a molded product having a hollow portion on the back side is manufactured by ordinary hollow injection molding and a flow mark is generated on the surface thereof.

FIG. 16 is an external view showing a state in which a similar vehicle molding is manufactured by hollow injection molding provided with a control pin according to the present invention and has no flow mark on its surface.

FIG. 17 is a horizontal cross-sectional perspective view of a thick-walled box-formed product by ordinary hollow injection molding.

FIG. 18 is a horizontal cross-sectional perspective view showing that a similar thick-walled box-shaped product is manufactured by hollow injection molding with a control pin according to the present invention, and the hollow part is formed in a constant shape so as to avoid the control pin. It is a figure.

[Explanation of symbols]

1 Injection molded product 11 Flow direction of resin 12 Molded product surface 13 Molded product cross section 14 Molded product opening 15 Flow mark 16 Resin gate 17 Thermoplastic resin in mold filling process 18 Weld 19 Injection molding machine spruce 20 Decorative integrated molding Product 21 Skin material 2,3 Mold section 2c Runner 31 Inert gas injection pin 32 Inert gas injection port 33 Inert gas injected into thermoplastic resin 4 Cavity 41 Final resin filling point in cavity 5 Control pin 5a, 5b Control pin 51,53 Control pin actuating spring 52,54 Control pin actuating rod 5a ', 5b' Recessed control pin 6 Air cylinder 61,62 Hydraulic cylinder 101 Molded part 102 by ordinary hollow injection molding 102 Control Hollow injection molded part with pin 103a Cross section of thick molded product with normal hollow injection molding 104a Cross section of thick molded product with hollow pin using control pin 103b, 104b Hollow in cross section of molded product Minute

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B29C 45/77 7365-4F B29C 45/77 // B29L 22:00

Claims (14)

[Claims] 1. Injection molding while controlling the flow direction, flow velocity, and pressure distribution of the injected resin by moving the tips of a plurality of control pins (5) into and out of the mold cavity (4). An injection molding method, which comprises: 2. The injection molding method according to claim 1, wherein the tips of the plurality of control pins (5a, 5b) are selectively taken in and out with time. 3. The plurality of controls described above so that an equal-pressure line substantially parallel to the peripheral edge of the cavity is formed inside the resin that has entered a region near the peripheral edge of the cavity during resin injection or mold clamping. The injection molding method according to claim 1 or 2, wherein the pins are arranged and the insertion / removal thereof is controlled. 4. The injection molding method according to claim 1, wherein injection compression molding is performed by clamping the mold after injecting the resin. 5. A skin material (21) and a thermoplastic resin (13)
The injection molding method according to any one of claims 1 to 3, wherein injection stamping molding is performed to integrally decorate. 6. The injection molding method according to claim 1, wherein a gas (33) is injected into the injection resin in the cavity to perform hollow injection molding. 7. The injection molding method according to claim 6, wherein the inflow and diffusion directions of the injected gas are also controlled by the plurality of control pins (5). 8. A plurality of control pins (5, 5) provided so that the tips of the mold cavities (4) can be taken in and out.
a, 5b) and a drive control device (51-54, 6, 61, 62) capable of controlling the control pin to be taken in and out, an injection molding die device. 9. The drive control device (51-54, 6, 6)
The injection molding die apparatus according to claim 8, wherein the tips of the plurality of control pins (5a, 5b) are selectively taken in and out over time. 10. The plurality of controls described above so that an equal-pressure line substantially parallel to the peripheral portion of the cavity is formed inside the resin that has entered a region close to the peripheral portion in the cavity of the injected resin during the resin injection period. The mold apparatus for injection molding according to claim 8 or 9, further comprising a drive control device for arranging the pins and controlling the taking-out / in of the pins. 11. The method according to claim 8, wherein injection molding is carried out by clamping the mold after injecting the resin.
Item 3. A mold device for injection molding according to item. 12. A skin material (21) and a thermoplastic resin (1
The injection molding die device according to any one of claims 8 to 10, which is configured to perform injection stamping molding in which (3) is decoratively integrally molded. 13. The method according to claim 8, wherein a gas injection port (32) for injecting a gas (33) is provided inside the injection resin in the cavity, and hollow injection molding is performed. The injection molding die apparatus described. 14. The injection molding mold apparatus according to claim 13, wherein the plurality of control pins (5) are also configured to control the diffusion direction of the injected gas.