JPH0224646B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a mold for a resin product. The applicant has previously developed a new manufacturing method for room-temperature curable resin products, in which a molded film made of synthetic resin film, rubber, etc. is adsorbed onto the top surface of a model box having a hollow chamber by reducing the pressure in the hollow chamber. After that, a frame equipped with a pressure reduction mechanism is placed and fixed on the top surface of the model box, and after filling the frame with granular materials such as metal particles, glass particles, and sand, the upper opening of the frame is covered with a shielding film. After coating, applying negative pressure to the internal particulate matter via the pressure reducing mechanism to solidify the particulate matter, and releasing the adsorption state of the formed film to the top surface of the model box, the frame is attached to the model box. Separate from the box to obtain a mold, and inject a liquid cold-curing resin into the cavity defined by combining multiple molds thus obtained to form the desired product. (Japanese Patent Application No. 116359/1982; Japanese Patent Application No. 8020/1983)
(see publication).

By the way, in manufacturing the mold, a rod-shaped model for a resin injection port is erected on the top surface of a model box. Although not shown in the above application, since it is necessary to exhaust air from the cavity of the mold during resin injection, a rod-shaped model for an exhaust port may be installed upright on the top of the model box. However, since these rod-shaped models are thin and tall, they often break when adhering the molded film to the top surface of the model box. The present invention has been made in view of the above-mentioned circumstances, and provides a molding method in which a resin injection port and an exhaust port can be formed without using a rod-shaped model, and which can be adsorbed onto the top surface of a model box without damaging the mold. The purpose is to provide a method for manufacturing molds.

Hereinafter, the present invention will be explained in detail based on examples. Fig. 1 shows a model box 1 used for carrying out the method of the present invention, and the model box 1 is made of wood (may also be made of plaster). A hollow chamber 2 is provided inside, and a model section 3 having a shape corresponding to the external shape of the room-temperature curable resin product is formed at the center of the upper surface of the hollow chamber 2. are in communication with each other through a large number of through holes 4. 5 is the hollow chamber 2
The opening 5 is connected via a ventilation pipe 6 to a vacuum pump (not shown).

The following is a step-by-step explanation of a method for manufacturing a mold for a cold-setting resin product and the product itself using the model box 1. First, one cylindrical sleeve 7 made of metal (plastic, glass, etc. may also be used) is installed at the center and end portions of the model section 3 on the top surface of the model box 1 (see FIG. 2).
When the sleeve 7 is installed on the inclined surface of the end of the model section 3, it is fixed using an adhesive with relatively weak adhesive force (a magnet may also be used). This is because the sleeve 7 must be separated from the model part 3 in the ninth step described later.

Second, a vacuum pump (not shown) is operated to reduce the pressure in the hollow chamber 2 of the model box 1, so that the atmosphere is sucked into the hollow chamber 2 from the top surface of the model box 1 through the through hole 4. When a molded film 8 made of a thermoplastic synthetic resin film that has been softened by preheating is attached to the top surface of the model box 1, the molded film 8 is attracted to the entire top surface of the model box 1 while being suction-stretched. At this time, the sleeve 7 is also covered with the molded film 8 (see FIG. 3). Thirdly, the molded film 8
A frame 9 with openings at the top and bottom is placed on the upper surface of the model box 1 covered with the above-mentioned model box 1 via positioning pins (not shown), and both are integrally clamped by a clamping device (not shown). (See Figure 3). A plurality of air-permeable intake pipes 11 are disposed inside the frame 9, and one end of the intake pipe 11 is connected to a hollow chamber (not shown) provided on one side of the frame 9. and the hollow chamber further includes:
It is connected to a vacuum pump (not shown). Fourth, the tip of the resin injection pipe 12 is airtightly fitted into the sleeve 7 at the center of the model section 3, and the tip of the exhaust pipe 13 is fitted into the sleeve 7 at the end (see Fig. 4). ). Note that the pipe 12,
The base end of the frame 9 is designed to slightly protrude from the upper end opening of the frame 9. Fifth, the space defined by the upper surface of the model box 1 and the frame 9 is filled with particulate matter 14 up to the upper end surface of the frame 9 (see FIG. 4). In this step, in order to increase the packing density of the granules 14, the frame 9 and the model box 1 are oscillated by a vibrator (not shown). Sixth, the upper opening of the frame 9 is covered with a shielding film 15 made of a synthetic resin film. At this time, the base ends of the pipes 12 and 13 are connected to the shielding film 1.
5 and protrudes upward, and the contact portion between the two is kept airtight (see Fig. 4). 7th
When the vacuum pump connected to the hollow chamber of the frame 9 is activated, the upper end opening of the frame 9 is covered with the shielding film 15 as described above. A negative pressure is applied via 11 and the granules 14 are solidified. Eighth, when the operation of the vacuum pump connected to the hollow chamber 2 of the model box 1 is stopped while the vacuum pump is operating, the inside of the hollow chamber 2 becomes normal pressure, and the vacuum pump is adsorbed to the upper surface of the model box 1. The formed film 8 that had been formed is dislocated and adsorbed to the particulate matter 14 side. Ninth, after unclamping the frame 9 and the model box 1 and releasing the adhesion between the sleeve 7 and the model box 3, the frame 9 is removed from the model box 1 together with the solidified granules 14. When separated, an upper mold u with a convex portion is obtained (see FIG. 5). Note that since the tips of the pipes 12 and 13 are still covered with the molded film 8, holes are bored therein by an appropriate method. Tenth, a lower mold D manufactured in the same manner as the upper mold U [however, the sleeve 7, the resin injection pipe 12 and the exhaust pipe 13]
When the upper die u is fitted with the upper mold u through dowel pins (not shown), a molded product cavity 16 is defined between the mating surfaces of the two (see FIG. 6). No.
11, the combination of the upper mold U and the lower mold D is placed on a surface plate (not shown), and the resin injection pipe 1 is placed.
When a liquid room-temperature curable resin is injected from 2 under atmospheric pressure or under pressure, the resin flows into the molded product cavity 16, and as a result, the cavity 16
The air inside is discharged into the atmosphere through the exhaust pipe 13. Twelfth, after completing the injection of the resin,
When the operation of the vacuum pumps connected to the upper mold U and the lower mold D is stopped after a predetermined curing reaction period, the negative pressure acting on the molds is released, and as a result, the vacuum pumps connected to the upper mold U and the lower mold D are stopped. Since the solidified state of the granular material forming the mold is thawed, the molded product (not shown) inside can be taken out. Finally, the sleeve 7, pipes 12, 13 attached to the molded product,
By removing unnecessary portions, burrs, etc. in the molded film 8, it is possible to obtain a product made of a room-temperature curing resin and having a thermoplastic synthetic resin film adhered to its surface.

In this embodiment, one resin injection port and one exhaust port are provided, but if the shape of the product is complex, a plurality of resin injection ports and multiple exhaust ports may be provided.

Furthermore, in this example, the resin injection port and the exhaust port are respectively arranged in the model section of the model box, but if it is inconvenient to leave these marks on the product, they can be placed on the top surface of the model box other than the model section. This may also be provided (see Figure 7).

Furthermore, in this embodiment, a plurality of air-permeable intake pipes are provided in the internal space of the frame as a suction mechanism for the frame, and a hollow chamber is provided on one side of the frame, and one end of the intake pipe is connected to the frame. Although the hollow chamber is connected in communication with the hollow chamber, a hollow chamber that can be ventilated with the inner wall side of the frame may be provided on the side wall of the frame.

As is clear from the above description, the present invention is a first step in providing an inlet for the resin and an outlet for air in the cavity of the molded product in a mold for a room-temperature curable resin product consisting of a model box. , a plurality of short sleeves are installed on the top surface of the model box, and
covering the sleeve with the upper surface and adsorbing the molded film;
In the second step, the tip of a pipe whose base end slightly protrudes from the upper end opening of the frame placed on the upper surface of the model box is hermetically fitted into each of the sleeves. Therefore, according to the present invention, since the rod-shaped models for the resin injection port and the exhaust port are not erected on the top surface of the model box, the molded film is not damaged when the molded film is adsorbed to the top surface of the model box. , manufacturing molds becomes easier.

In addition, in the example, a method for manufacturing a mold for resin products that hardens at room temperature was explained, but the present invention is not limited to molds that harden at room temperature, and can be applied to a wide range of manufacturing methods for molds for general resin products. can also be applied.

[Brief explanation of drawings]

1 to 6 are longitudinal sectional front views of an apparatus in each step of one embodiment of the manufacturing method of the present invention, and FIG. 7 is a longitudinal sectional front view of the apparatus in one step of another embodiment. 1: Model box, 3: Model part, 7: Sleeve, 8:
Molded film, 9: Frame, 12: Resin injection pipe, 1
3: exhaust pipe, 14: granular material, 15: shielding film, 16: molded product cavity, u: upper mold, D: lower mold.

Claims (1)

[Claims] 1. A cylindrical sleeve 7 is installed at an appropriate location on the top surface of the model box 1, and a stretchable molded film 8 is adsorbed to cover the sleeve 7 on the top surface of the model box 1, and then
A frame 9 equipped with a suction mechanism is placed on the top surface of the model box 1, and a pipe 1 whose base end protrudes from the top surface of the granular material filled in the frame 9.
After fitting the tips of 2 and 13 into the sleeve 7 airtightly and filling the space defined by the upper surface of the model box 1 and the frame 9 with granules 14, the frame 9
The upper end openings are covered with a shielding film 15, and the base ends of the pipes 12 and 13 are communicated with the atmosphere, and the particulate matter 14 is sucked and depressurized through the suction mechanism to solidify the formed film 8. After the adsorption state on the upper surface of the model box 1 was released, the frame 9 was separated from the model box 1 together with the solidified granules 14, and the tips of each of the pipes 12 and 13 were communicated with the atmosphere. A method for manufacturing a mold for resin products.