JPS63296905A - Manufacture of molding tool made of concrete - Google Patents

Abstract

PURPOSE:To make a mold surface of a molding tool smooth by releasing the molding tool easily from a molding model, by a method wherein a predetermined air gap is provided within the molding model and after an impermeable sheet having flexibility has been mounted on a molding surface of a mold of the model, cement slurry is cast onto the sheet by a suction device. CONSTITUTION:An air gap part 22 communicating with a suction device 21 is provided within a molding model 19 through an air flow path 32 whose one end is opened to a molding surface 20 of a mold at a plurality of positions, and the other end is provided on a base stand 17 as the molding model 19. When a sheet 25 composed of material such as polypropylene or ethylene vinyl acetate and having flexibility and impermeability is mounted on a frame 18 and a molding surface 20 of the mold of the molding model 19 and the suction device 21 is actuated, the sheet 25 is sucked to a side of the molding model 19 and the base stand 17 due to an atmospheric pressure difference and covers a surface part 30 of the molding model 19 and base stand 17. Cement slurry 28 is cast onto the base stand 17 and molding model 19 under a state where the sheet 25 is stuck close to the molding surface 20 of the mold while keeping an actuation state of the suction device 21 on.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a method for manufacturing a mold using concrete as a mold material.

(Conventional technology) Compared to the past, 1. As shown in FIG. 9, when manufacturing a mold 1 using concrete as a mold material, first a molding model 2 is created, which is made of wood or plaster and has a molding surface 5 that corresponds to the surface of the mold. Then, a formwork 3 is attached and fixed to the upper part of the circumferential surface of the molded model 2 by means of bolts 4 or the like, and the upper part of the molded model 2 is surrounded by the upper part of the formwork 3. After applying a mold release agent 6 on the molding surface 5, cement slurry is poured into the mold to produce a mold 1 using either the upper mold or the lower mold as a mold material.

(Problems with the prior art) By the way, such a mold release agent 6 is one that uses various commonly used mold release agents and is applied thinly using a spray to clearly show the molding surface 5. It is. Therefore, when the cement slurry is poured, the moisture contained in the cement slurry permeates into the mold release agent 6 and the surface treatment agent of the molded model 2 together with the fine cement particles, and the water contained in the cement slurry permeates into the mold release agent 6 and the surface treatment agent of the molded model 2 made of wood or plaster. Because it penetrates into the molding surface 5, when the concrete mold 1 hardens and hardens, it becomes difficult to release the mold 1 from the molding surface 5 of the molded model 2 due to the anchoring effect, and when it is released, In many cases, the shape of the mold surface collapses, making it impossible to obtain a smooth mold surface.
There was a problem. On the other hand, in order to solve this problem, it is possible to create the molding model 2 from silicone rubber, etc., but this would increase the manufacturing cost of concrete molds and prolong the manufacturing period. existed.

Therefore, the technical problem of the present invention is to make the mold surface of the mold smooth by allowing the concrete mold to be easily released from the molding model.

[Technical means for solving the problem] In order to solve such a technical problem, the present invention provides a plurality of holes in the molding model, one end of which is connected to the molding surface, and the other end of which is connected to a suction device. After providing a communicating gap and placing a flexible non-breathable sheet over substantially the entire surface of the molding surface of the model, the air in the gap is sucked and discharged by the suction device, and the sheet is removed. In this method, cement slurry is poured into the molding surface of the molding model to form a mold for concrete.

〔Example〕

The present invention will be described in detail below based on embodiments shown in the accompanying drawings. Incidentally, the same members as those in the prior art are given the same reference numerals, and the explanation thereof will be omitted.

1 to 4 show a first embodiment of the invention. In this example, a mold for injection molding was manufactured by the method of manufacturing a mold for concrete according to the present invention.First, as shown in FIG. The formwork 18 is attached and fixed, and the wooden molded model 19 is also attached. In this embodiment, the molded model 19 and the surface portion 30 of the base 17 form a molded model. Inside this molded model 19, one end has a plurality of holes opened to the molding surface 20, and the other end is provided with a suction device 2 through an air passage 32 provided in the base 17 serving as the molded model.
A void portion 22 communicating with 1 is provided. The void 2
2 is provided in the molded model 19 along a substantially horizontal direction,
It consists of a main cavity 23 that communicates with an appropriate suction device 21, and a plurality of communication passages 24 with a small diameter provided between the main cavity 23, the molding surface 20, and the main cavity 23. Communication path 2
4 are opened at appropriate intervals at key points of the molding surface 20, for example, at bent portions with large curvatures as shown in the drawings.

On the other hand, in this embodiment, a flexible and non-breathable sheet 25 is prepared in advance;
5 is polypropylene, for example.

Made of materials such as ethylene vinyl acetate, 0.05
It is formed to have a thickness of mm to Q and 1 mm.

When producing an injection mold for concrete using the molding model 19 according to this embodiment, first, the molding model 19 is prepared by using an appropriate means (for example, a heat plate). The base 17 and the formwork 18 are heated to a predetermined temperature. Thereafter, as shown in FIG.
is placed on the mold frame 18 and the molding surface 20 of the molded model 19. When the suction device 21 having an appropriate configuration is operated, the main cavity 23 and the plurality of communication passages 24
The gap 2 between the sheet 25 and the molding surface 20 is
Since the air in the sheet 25 is sucked and discharged, the sheet 25 is drawn toward the molded model 19 and the base 17 due to the pressure difference, and covers the molded model 19 and the surface portion 30 of the base 17. Then, when the sheet 25 comes into contact with the molding surface 20,
Since the molded model 19 is heated, the sheets 1 to 25 are softened and come into close contact with the molding surface 20 evenly, as shown in FIG. At this stage, sheet 25
Of these, portions that deviate from the surface of the molding surface 9 are appropriately removed. Further, when the molding surface 20 of the molding model 19 has a complicated shape, an adhesive may be applied to the molding surface 20 in advance and the molding surface 20 may be pressed down manually or the like. Thereafter, while maintaining the suction device 21 in operation and with the sheet 25 in close contact with the molding surface 2o, the cement slurry 28 is applied to the base 17 and the molding model 19.
Pour it on top. Then, a predetermined amount of cement slurry 28
After the liquid is poured, as shown in FIG.
The cement slurry 28 is injected until it reaches the upper edge of the formwork 18. In addition, the reference numeral 31 in the figure is a hole for air vent. In this state, the cement slurry is solidified and hardened to form a mold 27 for injection molding of concrete for the cavity or core.

Therefore, in this embodiment, the molding model 19 and the formwork 1
A sheet 25 is arranged in close contact with the inner surface of the
A concrete injection mold 27 is inserted through the sheet 25.
is formed, so that the moisture in the cement slurry does not penetrate into the surface of the molded model 19 together with the fine cement particles, and between the mold surface 28 of the mold 27 and the molded model 19 and mold frame 18. It is possible to prevent a situation in which the anchor effect is activated.

FIG. 5 to FIG. 8 show a second embodiment of the method for manufacturing a mold for concrete according to the present invention, and in this embodiment,
A mold for press molding was manufactured using the method for manufacturing a mold for concrete according to the present invention. As shown in FIG. 5, in this embodiment, similarly to the previous embodiment, there is a cavity in the molded model 8, in which a plurality of holes are opened to the molding surface 9 at one end and the other end communicates with the suction device 10. 11 are provided. The cavity 11 is provided in the molded model 8 along a substantially horizontal direction, and includes a main cavity 12 that communicates with an appropriate suction device 10, and a main cavity 12, a molding surface 9, and the main cavity 12. and a plurality of small-diameter communication passages 13 provided between the two. The small-diameter communication passages 13 are opened at various locations on the molding surface 9 at appropriate intervals.

When producing a mold for press forming concrete using the molding model 8 according to this embodiment, first, the molding model 8 is heated to a predetermined temperature by an appropriate means (for example, a heat plate). Heat it up. Thereafter, as shown in FIG. 6, a flexible, air-impermeable sheet 14 formed to a thickness based on the blank is placed on the molding surface 9 of the molded model 8. Then, the suction device 10 having an appropriate configuration is operated, and the air in the gap 15 between the sheet 14 and the molding surface 9 is sucked and discharged through the main gap 12 and the communication path 13. Due to the pressure difference, the sheet 14 approaches the molding surface 9 and then comes into contact with it.

Then, when the sheet 14 comes into contact with the molding surface 9,
Since the molded model 8 is heated, the sheet 14 is thermally deformed and comes into close contact with the molding surface 9 evenly, as shown in FIG. At this stage, the portion of the sheet 14 that deviates from the surface of the molding surface 9 is appropriately cut off. Thereafter, as shown in FIG. 8, while maintaining the operating state of the suction device 10 and keeping the sheet 14 in close contact with the molding surface 9, cement slurry is poured onto the molding model 8, and the cement slurry is poured onto the upper mold. Alternatively, a mold 16 is formed using the concrete of the lower mold as a mold material.

Generally, when manufacturing molds for concrete,
First, either an upper mold or a lower mold is produced using a molding model, and then an upper mold or a lower mold is produced using the produced mold as a model.

After that, it was necessary to perform a so-called plate thickness cutting operation in which the mold surface and die face of the upper mold or lower mold were cut by the thickness of the blank. In the mold manufacturing method, when cement slurry is poured into the molding model 8 to form a mold using concrete as a mold material, the concrete mold 16 is molded with the thickness of the blank removed. Therefore, there is no need to perform the work of thickness-cutting the plate as in the past, and the number of man-hours required for manufacturing molds for concrete can be reduced.

(Effects of the Invention) Since the present invention has the above configuration, even when a mold for concrete is produced, the mold for concrete can be easily released from the molding surface of the molding model, and This has the effect of making the mold surface extremely smooth.

[Brief explanation of the drawing]

1 to 4 show a first embodiment of the method for manufacturing a mold for concrete according to the present invention, in which a mold for injection molding is manufactured according to the present invention. A cross-sectional view showing a molding model, a mold suction device, and a sheet according to an example; FIG. 2 is a cross-sectional view showing a sheet placed on a mold; FIG. 3 is a cross-sectional view showing a state in which the sheet is placed on a mold, and FIG. A cross-sectional view showing a state in which cement slurry is flowing in while being in close contact with the model mold surface, FIG. 4 is a cross-sectional view showing a state in which a mold using concrete as a mold material is molded on the molded model via a sheet, 5 to 8 show a second embodiment of the method for manufacturing a mold for concrete according to the present invention, in which a mold for press molding is manufactured according to the present invention, and FIG. 6 is a sectional view showing a sheet placed on the molding model, and FIG. 7 is a sectional view showing the sheet placed on the molding model by activating the suction device. 8 is a sectional view showing a state in which a mold made of concrete is molded onto the molding model through a sheet, and FIG. FIG. 2 is a cross-sectional view showing a method of manufacturing a mold used as a mold material. 1.16.27...Mold made of concrete 3.18...Formwork 2.8.19...Molding model 5.9.20...Mold forming surface 10.21... Suction device 11.22...Gap portion 14.25...Sheet

Claims (1)

[Claims] In a method for manufacturing a concrete mold, in which cement slurry is poured onto a molded model surrounded by a formwork to form a concrete mold, the molded model has a plurality of holes at one end facing the molding surface, and at the other end. After providing a gap communicating with a suction device and placing a flexible and non-breathable sheet on at least the entire molding surface of the model, the air in the gap is removed by the suction device. 1. A method for manufacturing a concrete mold, which comprises sucking and discharging the sheet, pouring cement slurry into the molded model with the sheet in close contact with the molding surface of the molding model, and solidifying and hardening the cement slurry.