JP3400020B2 - Mold for injection press molding - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection press molding die for press molding a resin molded product such as an instrument panel of an automobile while injecting a resin material. Things. 2. Description of the Related Art Conventionally, an injection press molding die has a core die 2 having a gate 1 for injecting a molten resin as shown in FIG.
And a cavity mold 3 that can move in a direction approaching and separating from the core mold 2. The core mold 2 has a shut-off valve 1a for injecting an appropriate amount of the plasticized resin material 5 supplied from the resin injection unit 6 connected to the core mold 2 through the gate 1. The cavity mold 3 and the core mold 2
The gate 1 is provided on the back surface 4a of the skin material 4 interposed therebetween.
The molded resin 8 is formed in the mold by pressing the skin material 4 and the resin material 5 from above and below by injecting the molten resin material 5 from above. At the time of this mold clamping, the skin material 4 and the resin material 5
The air in the mold interposed therebetween gradually moves to the inner periphery of the mold as the resin material 5 spreads, and the skin material in the vicinity of the shear edge portion 7 which is the periphery of the part to be the molded product 8. The core 4 is extruded to the outside through a gap between the core 4 and the core mold 2. For this reason, the shear edge portion 7 is configured to have a constant interval of generally about 0.8 mm in the mold-clamped state. [0005] However, in such a mold for injection press molding, in a state where the mold is clamped,
Resin leakage may occur from the shear edge portion 7 having a constant interval, causing burrs 5a and / or variations in molded product weight due to short shots. Also, in the step of cutting off the peripheral end portion 8b along the trimming line 8a on the periphery of the molded product 8 as shown in FIG. 7, the thickness of the resin portion on the trimming line 8a increases. The workability was not good because the pressure of the trimming device had to be increased and the number of trimming steps had to be increased. Further, since the skin material 4 easily moves at the shear edge portion 7, wrinkles are generated on the surface of the molded product 8. For this reason, it is desirable to set the interval between the shear edge portions 7 to be small. However, if the interval between the shear edge portions 7 is narrowed, the skin material 4 is attached to the core material before the air in the mold is completely removed. Sandwiched between the mold 2 and the cavity mold 3,
There is a possibility that air accumulation occurs in the mold and air swells in the molded product 8. Accordingly, an object of the present invention is to provide an injection press molding die capable of bleeding air from the inside of the die even when the distance between the portions sandwiching the skin material on the periphery of the molded product is set to be small. According to the present invention, in order to achieve the above object, according to the first aspect of the present invention, the skin material interposed between the cavity mold and the core mold is provided on one side surface thereof. Inject the molten resin material from the gate formed in the core mold, and in the injection press molding mold to mold and mold with the cavity mold and the core mold, in the mold clamped state,
It has a shear edge portion for setting the interval between the cavity mold and the core mold so as to sandwich the skin material on the periphery of the part to be a molded product, and communicates the inside and outside of the mold at the time of mold clamping and air in the mold. Is provided on the weld line portion of the core mold, and the air bleed means is formed between the mold end of the cavity mold and the opposing surface on the core mold side as the molded product. An injection press molding die having a plurality of grooves formed along the weld line on a surface facing the core die of a shear edge portion sandwiching a skin material of the peripheral edge. [0013] In the injection press molding die of the present invention configured as described above, in the clamped state, the skin material on the periphery of the part to be a molded product is sandwiched. Since the interval between the cavity mold and the core mold is set as described above, there is no occurrence of resin leakage or movement of the skin material when performing mold clamping. [0014] Further, the air release means for communicating the inside of the mold with the outside at the time of mold clamping and discharging the air inside the mold to the outside is provided at the weld line portion and the shear edge portion of the core mold. Is discharged to the outside through the air release means. In particular, the mold end of the cavity mold and the core mold
In the shear edge portion sandwiching the skin material of the periphery of the part to be a molded product with the opposing surface on the side, on the opposing surface on the core mold side, a plurality of air slits provided along the weld line are provided. Along the groove, the air in the mold is guided to the outside and discharged. For this reason, even if the interval between the shear edge portions is set to be small, an escape path for air in the mold is ensured, and there is no possibility that air swelling occurs in the molded product. An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1 to 3 show an injection press molding die 10 for molding an instrument panel or the like of a vehicle according to a first embodiment of the present invention. The injection press molding die 10 mainly includes a core die 12 having a plurality of gates 11 for injecting a molten resin, and a cavity die 13 movable in a direction approaching and separating from the core die 12. It is configured. An appropriate amount of plasticized resin material 15 supplied from a resin injection unit (not shown) connected to the core mold 12 is injected into the core mold 12 through the gates 11. So that a shut-off valve is provided inside. The core mold 12 is provided with an air bleeder in the weld line section for communicating the inside and outside of the mold at the time of mold clamping and discharging the air in the mold to the outside. The air bleeding means is provided on the opposing surface 1 on the core mold 12 side of the shear edge portion 17 which is the portion sandwiching the skin material 14 on the periphery of the portion to be the molded product 16.
2a, a plurality of air slits 18 communicating between the inside and the outside of the mold, and a large number of pores formed at a portion where the resin material 15 on the core mold 12 contacts the inside and outside of the mold. And a plurality of air vents 19. The air slit 18 has a width and a depth of about 0.2 mm and about 0.5 mm formed along a weld line formed at a joining position of the resin material 15 flowing from the plurality of gates 11. Generally, grooves 18a are arranged in parallel at intervals of 3 mm. The air vent 19 is formed between the gates 11 at an equal distance from the gates 11, and has an air vent hole 19 a extending axially downward from the upper surface of the core mold 12. This air vent hole 1
And a plug member 19b made of a sintered metal having a plurality of pores having a diameter of 0.5 mm or less embedded in the plug 9a. These pores do not transmit the molten resin material 15, but can transmit air. Further, a plurality of rib grooves 12b and boss forming portions 12c for forming ribs and bosses are formed on the back side of the molded product. This rib groove 12
(b) Since the air easily accumulates in the boss forming portion 12c, it is important to arrange the air vent 19 forming positions evenly. The lowermost position of the cavity mold 13 is set such that the end 13a of the cavity mold 13 and the core mold 12 are sandwiched between the skin material 14 on the periphery of the part to be the molded product 16 in the clamped state. It is configured to set the interval of the shear edge portion 17 as the interval with the side facing surface 12a. This interval is generally about 0.4 mm. Next, the operation of the first embodiment will be described. In the injection press molding die 10 of the first embodiment thus configured, first, a skin material 14 is interposed between the cavity mold 13 and the core mold 12. An appropriate amount of molten resin material 15 is injected from the gates 11 to the back surface 14a of the skin material 14, and the skin material 14 and the resin material 15 are pressed from above and below by the cavity mold 13 and the core mold 12, At the same time, welding, cooling,
The resin material 15 is fixed to the skin material 14 as a core material to form a molded product 16 such as an instrument panel of a vehicle. At this time, the molded product 16 is
The end surface 13 a of the cavity mold 13 and the opposing surface 1 on the core mold 12 side so as to sandwich the skin material 14 on the periphery of
Since the interval of the shear edge portion 17 which is an interval from the second edge portion 2a is set, the resin material 15 leaks from the shear edge portion 17 to the outside when the mold is clamped, and resin burrs are generated. Since the occurrence of the variation can be suppressed and the skin material 14 does not move, the occurrence of wrinkles on the skin portion of the molded product 16 can also be prevented. Further, even if a small amount of resin burr occurs, in the molded product 8 as shown in FIG. 7, the thickness of the resin on the trimming line 8a is small, and the trimming of the offcut portion 8b can be easily performed. Therefore, workability is good. When the mold is clamped, the inside and outside of the mold are communicated with each other to discharge the air inside the mold to the outside.
The air in the mold is discharged to the outside through these air vents. That is, first, most of the air in the mold interposed between the resin materials 15, 15 spread by pressing is released by the air vent 19 formed between the gates 11,. Eventually, the air vent 19 is covered with the spread resin material 15, but the air in the remaining mold, particularly between the back surface side 14 a of the skin material 14 and the resin material 15, is subjected to the pressurization while receiving the pressurization. The air is guided to the air slits 18 and discharged from the inside of the mold to the outside. For this reason, even if the interval between the shear edge portions 17 is set to be narrow as described above, an escape route for air in the mold is secured, and the residual air in the mold becomes very small.
This eliminates the risk of air swelling. FIG. 4 shows an injection press molding die 20 according to a second embodiment. This injection press molding die 2
On the opposing surface 22a of the 0 core mold 22, an air slit 28 composed of a plurality of grooves 28a... Other configurations and operations are substantially the same as or equivalent to those of the first embodiment, and therefore description thereof is omitted. In each of the above embodiments, the air vent 19 is formed by using the plug member 19b made of sintered metal having a large number of pores. However, the present invention is not limited to this. In a portion where 15 contacts, there are many pores communicating between the inside and the outside of the mold, regardless of the configuration, such as one in which many pores communicating between the inside and the outside of the mold are formed by wire electric discharge machining. If it is something, it is natural. As described above, according to the present invention, the interval between the shear edge portions can be set to be small, so that resin leakage occurs when the mold is clamped or the skin material moves. Nothing. For this reason, it is possible to suppress the occurrence of resin burrs and the occurrence of variations in the weight of the molded product due to short shots, and also to prevent the occurrence of wrinkles on the skin of the molded product. Then, the air in the mold is discharged to the outside through the air bleeding means. In particular, in the opposing surface of the core mold side to the cavity of the mold end portion, wherein in the said share edges sandwiching the skin material of the periphery of the portion to be a molded article, the facing surface of the core mold side, wherein the weld Along the plurality of grooves of the air slit provided along the line, the air in the mold is guided to the outside and discharged. For this reason, an escape route for air in the mold is ensured, and there is a practically useful effect that there is no possibility of air accumulation in the molded product.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a core mold showing an injection press molding mold according to a first embodiment of the present invention. FIG. 2 is a perspective view showing an injection press molding die of the same embodiment, showing an air slit formed in a core die. FIG. 3 is a partially enlarged sectional view of a periphery of a molded product, showing a state in which a mold for injection press molding of the same embodiment is clamped. FIG. 4 is a perspective view of an injection press molding die according to a second embodiment, showing an air slit formed in a core die corresponding to FIG. 2; FIG. 5 is a partial cross-sectional view illustrating a conventional injection press molding die and illustrating an overall arrangement of the apparatus. FIG. 6 is a partially enlarged sectional view of a peripheral edge of a molded product, showing a state in which a conventional injection press molding die is clamped. FIG. 7 is a perspective view showing an example of a molded product. [Description of Signs] 10,20 Injection press molding die 11 Gate 12 Core die 13 Cavity die 14 Skin material 15 Resin material 16 Molded product 18,28 Air slit (One of air release means) 19 Air vent (Air release means) one of)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-284212 (JP, A) JP-A-4-53718 (JP, A) JP-A 5-58243 (JP, U) JP-A 3-58 42630 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 33/00-33/76 B29C 45/00-45/84

Claims (1)

(57) [Claim 1] A molten resin material is injected from a gate formed in the core mold into one side surface of a skin material interposed between the cavity mold and the core mold to form the cavity. In the injection press molding die that molds and molds with the mold and the core mold,
In a state in which the mold is clamped, the mold has a shear edge portion for setting an interval between the cavity mold and the core mold so as to sandwich the skin material on the periphery of a part to be a molded product, and communicates with the inside and outside of the mold at the time of mold clamping. Air venting means for discharging air in the mold to the outside is provided in the weld line portion of the core mold, and the air venting means comprises a mold end of the cavity mold and an opposing surface on the core mold side , An injection press molding metal, comprising: a plurality of grooves formed along the weld line on a surface facing the core mold side of a shear edge portion sandwiching a skin material of a periphery of the molded product. Type.