JP2001018243A - Mold for molding and method for molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate fear of remaining of gas such as air in a product and to suppress generation of a defective item by setting a position for forming an opening of a vent through-hole in the neighborhood of a corner of a molded item where the gas such as air tends to remain. SOLUTION: When a rectangular molded item is molded, an opening 7 of a vent through-hole 6 formed on a mold part 3 on the underside of a mold is arranged in the neighborhood of the corner part r of a molding region R. When vaccum processing in the mold is performed in molding process, as gas such as air can be surely eliminated from the corner of the molded item where deaeration is conventionally not good, generation of a defective item caused by remaining of gas such as air in a product is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding die and a molding method in which molding parts are combined and a molding material disposed therebetween is molded under pressure.

[0002]

2. Description of the Related Art FIG. 4 shows an example of a molding die 1 for molding a resin product. The illustrated mold 1 is composed of two mold parts 2 and 3 which are vertically divided. In this example, the upper mold part is a female mold and the lower mold part is a male mold, and the lower mold part 3 is on the base B. Is mounted and fixed.

After the molding material S is placed on the surface of the lower mold portion 3 of the molding die 1, the upper mold portion 2 is united and pressed, and the molding material S is pressed between the upper and lower mold portions 2, 3. , A desired molded product can be obtained. When a thermosetting molding material S such as SMC or BMC is used for molding an FRP product such as a bathtub or a waterproof pan, the molding material is pressurized and heated.

FIG. 5 shows upper and lower mold portions 2 of the molding die 1.
FIG. 3 is a cross-sectional view of a state in which the molding material 3 is united to form a molding material S under pressure. As shown in the figure, a very narrow (for example, about 0.1 to 0.3 mm) ventilation gap 4 is formed between the upper and lower mold parts 2 and 3 at the outer edge of the molding space filled with the molding material S. A communication space 5 is formed on the outer periphery of the ventilation gap 4, and a ventilation through hole 6 opening toward the communication space 5 is formed in the lower mold portion 3. The ventilation through-hole 6 is connected to a decompression means (not shown) such as a vacuum pump and the like. The inside of the mold 1 is depressurized through 6 to deaerate the molding material S and assist the spreading of the molding material S.
The upper and lower mold portions 2 are located at appropriate places outside the communication space 5.
A packing P is provided between the molds 3 so that the inside of the mold 1 becomes a closed space when the mold parts 2 and 3 are combined.

[0005]

FIG. 6 shows the lower mold part 3.
FIG. When a product having a rectangular planar shape is molded, the molding region R of the mold portion 3 also has a rectangular shape as shown in FIG. Conventionally, the opening 7 of the ventilation through hole 6 formed in the mold portion 3 is set so as to be near the center of each side of the molding region R. Therefore, when the inside of the molding die 1 is maintained in a reduced pressure state during the molding process, there is a possibility that corners of the molded product far from the opening 7 of the ventilation through hole 6 may be insufficiently degassed. If gas such as air remains in the molded product, pinholes are generated on the surface of the molded product, deteriorating the surface properties and aesthetics, and thus necessitating repair. In addition, the pinhole causes a decrease in stain resistance and strength particularly in a resin product which frequently changes in temperature, such as a bathtub or a waterproof pan.

As shown in FIG. 5, the molding material S flows out of the ventilation gap 4 formed at the outer edge of the molding space of the molding die 1 due to the reduced pressure during the molding process. There is a problem that a part is scattered or flows and is drawn into the ventilation through hole 6. When the molding material S is drawn into the ventilation through-hole 6, the ventilation resistance of the ventilation through-hole 6 is increased or a blockage is caused, and further, a depressurizing means such as a vacuum pump is adversely affected, and the molded product is degassed. Processing may not be performed sufficiently. Conventionally, as shown in FIG. 7, it has been attempted to prevent a molding material from entering by attaching a cap 9 having a net body 8 or the like to the opening 7 of the ventilation through hole 6, but the effect is not sufficient. In addition, there is a disadvantage that the cap 9 must be frequently replaced due to clogging of the net body 8.

[0007]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention provides first to third molds described below. The features of the first mold according to the present invention are as follows.
The molding material disposed therebetween is subjected to pressure molding by the united mold portion, wherein a narrow ventilation gap is formed at the outer edge of the molding space of the molding material, and a communication space is formed on the outer periphery of the ventilation gap, A ventilation through-hole opening toward the communication space is formed in the mold portion, and the position of the opening of the ventilation through-hole is set near the corner of the molded article.

Another feature of the second molding die according to the present invention is that a molding material disposed therebetween is press-molded by a united mold portion, and the molding material is formed on an outer edge of a molding space of the molding material. A narrow ventilation gap is formed, a communication space is formed on the outer periphery of the ventilation gap, a ventilation through hole that opens to the communication space is formed in the mold portion, and the ventilation gap near the opening of the ventilation through hole is formed. Is provided with a dustproof cover on the side facing.

Further, a feature of the third molding die according to the present invention is that the molding material disposed therebetween is press-molded by the united mold portion, and the outer edge of the molding space of the molding material is formed. A narrow ventilation gap is formed, a communication space is formed on the outer periphery of the ventilation gap, a ventilation through hole that opens to the communication space is formed in the mold part, and an opening of the mold part is formed in the opening of the ventilation through hole. That is, an extension member protruding from the surface is provided.

In the present invention, when the molding material is pressure-molded using the first to third molding dies, the molding material is molded through a ventilation through hole formed in a mold portion of the molding die. The present invention provides a molding method in which the inside is decompressed and compressed air is supplied into the molding die through the vent holes when the molded product is released from the mold.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] FIG. 1 shows an embodiment relating to a first molding die according to the present invention. FIG. 3 is a plan view of the lower mold portion 3 placed on the base B when the mold 1 is composed of upper and lower mold portions. The present invention has a feature in that, when a product having a rectangular shape in a plan view is formed, the opening 7 of the ventilation through hole 6 formed in the mold portion 3 is arranged near the corner r of the forming region R. are doing. With such a configuration, when depressurizing the inside of the molding die 1 in the molding step, gas such as air can be reliably removed from the corners of the molded product, which has conventionally had a great risk of degassing. Therefore, the occurrence of defective products due to the gas such as air remaining in the product is suppressed.

[Second Embodiment] FIGS. 2 and 3 show an embodiment in which the structures of the first and second molding dies according to the present invention are combined, and FIG. FIG. 3 is an enlarged cross-sectional view showing the structure of the opening 7 of the ventilation through hole 6 formed in the mold portion 3 of FIG. As shown in the drawing, this embodiment is characterized in that a dustproof cover 10 is provided near an opening 7 so as to cover a side facing a ventilation gap 4 formed between upper and lower mold parts 2 and 3. have.
By providing the dustproof cover 10, when the inside of the mold 1 is decompressed, the molding material flowing out from the ventilation gap 4 is not covered with the opening 7.
Even if it splatters toward, it can be prevented from entering into the ventilation through hole 6. In this example, the dustproof cover 10 has a hemispherical dome shape. However, the dustproof cover 10 may be a flat plate as long as it can shield the space between the opening 7 and the ventilation gap 4. There is no. Further, the dustproof cover 10 may be formed of a fine mesh or the like to provide air permeability.

In this embodiment, an extension member 20 projecting from the surface of the lower mold part 3 is attached to the opening 7 with a screw 21 or the like, and a net 8 or the like is attached to the upper end thereof. I have. With such a configuration, the substantial opening position of the ventilation through hole 6 is above the surface of the mold portion 3. Therefore, even if the molding material flowing out of the ventilation gap 4 flows on the surface of the mold portion 3, since the opening position is high, it does not easily enter the ventilation through hole 6.

As described above, in this embodiment, the dust-proof cover 10 prevents the fragments of the molding material from reaching the opening 7, and the extension member 20 covers the surface of the mold portion 3. Since the flowing molding material is prevented from reaching the opening 7, there is no possibility that the molding material enters the ventilation through hole 6. In addition, since the clogging of the mesh body 8 attached to the opening 7 is reduced, there is an advantage that the replacement frequency of the mesh body 8 can be reduced as compared with the related art.

[Third Embodiment] Mold 1 according to the present invention
When molding a molding material using the method described below, the following molding method can be employed. As described above, at the time of pressure molding, the inside of the mold 1 is depressurized by a decompression means such as a vacuum pump through the ventilation through hole 6 to deaerate the molding material and at the same time assist the spreading of the molding material. In the present embodiment, the compressed air supply means is also connected to the ventilation through hole 6, and after the molding step is completed, the compressed air is supplied into the molding die 1 through the ventilation through hole 6. Thereby, separation of the mold parts 2 and 3 and
Demolding of the molded product can be assisted.

[Other Embodiments] In the above embodiment, the upper mold part is a female mold and the lower mold part is a male mold. Conversely, the upper mold part is a male mold and the lower mold part is a male mold. The present invention is applicable to a female type. Further, the formation position of the opening of the ventilation through hole may be formed in the vicinity of the corner of the molded product and also in the middle of each side. In addition, the present invention does not prevent modification as appropriate according to the situation of implementation.

[0017]

According to the first molding die of the present invention, the position of the opening of the ventilation through hole is set near the corner of the molded product in which gas such as air is likely to remain. The possibility of remaining gas can be eliminated, thereby suppressing the occurrence of defective products.

In the second mold of the present invention, the dust-proof cover is provided on the side facing the ventilation gap near the opening of the ventilation through-hole, so that the molding material is prevented from being drawn into the ventilation through-hole. Can be. Further, the third mold of the present invention comprises:
By providing the extension member at the opening of the ventilation through hole, the substantial opening position is projected from the surface of the mold portion, so that the inflow of the molding material can be prevented. Therefore, any of the molds can prevent blockage of the ventilation through hole and increase in ventilation resistance due to intrusion of the molding material, and can prevent adverse effects on the decompression means communicating with the ventilation through hole. The effect of stabilization is obtained. In addition, the frequency of replacing a net or the like mounted on the opening can be reduced.

By employing the molding method according to the present invention and supplying compressed air into the molding die through the through holes after the pressure molding, separation of the mold portion and removal of the molded product can be promoted. Further, by passing the compressed air, there is obtained an advantage that clogging of a net or the like attached to the opening of the ventilation through hole can be removed.

[Brief description of the drawings]

FIG. 1 relates to a first embodiment of the present invention and is a plan view showing an example of a lower mold portion in a molding die.

FIG. 2 relates to a second embodiment of the present invention and is a cross-sectional view showing a structure around an opening of a ventilation through hole.

FIG. 3 relates to a second embodiment of the present invention and is a plan view showing a structure around an opening of a ventilation through hole.

FIG. 4 is a front view showing a conventional mold, in which upper and lower mold parts are separated, and an upper mold part is shown in cross section.

FIG. 5 is a cross-sectional view of a main part, showing a conventional molding die, showing a situation where a molding process is being performed by combining upper and lower mold portions.

FIG. 6 is a plan view showing a lower mold portion of a conventional molding die.

FIG. 7 is a cross-sectional view showing a structure around an opening of a ventilation through hole in a conventional molding die.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Mold 2 ... Upper mold part 3 ... Lower mold part 4
... ventilation gap 5 ... communication space 6 ... ventilation through hole 7 ... opening 8 ... net 9 ... cap 10 ... dustproof cover 20 ...
Extension member 21: Screw B: Base S: Molding material P
… Packing

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F202 AM28 CA09 CB01 CM16 CP05 CP07 4F204 AM28 FA01 FB01 FN11 FN12 FN20 FQ15

Claims (4)

[Claims] 1. A molding die for press-molding a molding material disposed therebetween by means of a united mold portion, wherein a narrow ventilation gap is formed at an outer edge of a molding space of the molding material and communicates with an outer periphery of the ventilation gap. A space is formed, and a ventilation through-hole opening toward the communication space is formed in the mold portion, and the position of the opening of the ventilation through-hole is set near the corner of the molded product. Mold. 2. A molding die for press-molding a molding material disposed therebetween by a united mold portion, wherein a narrow ventilation gap is formed at an outer edge of a molding space of the molding material and communicates with an outer periphery of the ventilation gap. A space is formed, a ventilation through-hole opening toward the communication space is formed in the mold portion, and a dust-proof cover is provided on the side facing the ventilation gap near the opening of the ventilation through-hole. Mold. 3. A molding die for press-molding a molding material disposed therebetween by a united mold portion, wherein a narrow ventilation gap is formed at an outer edge of a molding space of the molding material and communicates with an outer periphery of the ventilation gap. A space is formed, a ventilation through-hole opening toward the communication space is formed in the mold portion, and an extension member protruding from the surface of the mold portion is provided in an opening of the ventilation through-hole. Mold. 4. A method for press-molding a molding material using the molding die according to claim 1, wherein the molding material is molded through a ventilation hole formed in a mold portion of the molding die. A molding method, wherein the inside of the mold is depressurized through the hole, and compressed air is supplied into the mold through the vent hole when the molded article is released from the mold.