JPH0144795B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a mold manufactured by electroforming in which a vent hole is formed through a cavity.

For example, molds manufactured by electroforming are used to manufacture molded products with complex surface irregularities, but the molds have air vent holes and vacuum holes for injection molding and blow molding. In the case of molding, it is necessary to provide suction holes. Conventionally, in order to form these holes, holes were drilled directly into the cavity after electroforming, but the surface shape of the mold has an uneven shape that is opposite to the surface of the molded product. Therefore, the hole formed in the concave part of the cavity by a drill is likely to be located at a position corresponding to the convex part of the molded product, making the outer shape of the molded product unsightly. This is extremely difficult because a thin drill with a small hole diameter is used, and the tip of the drill tends to slip and become misaligned when drilling the hole.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to easily form small-diameter ventilation holes at positions corresponding to the convex portions of the cavity, and to improve the external shape of the molded product. An object of the present invention is to provide a method for manufacturing a mold manufactured by electroforming.

An embodiment of the present invention will be described below with reference to the drawings.

In Fig. 1, reference numeral 1 denotes a master mold made of wood, plastic, metal, etc., and the surface part 2 of this mold has a protrusion 2 (not shown) that matches the external shape of the molded product.
a and a recess 2b are formed. For example, when producing a molded product with a leather pattern on the surface, the master 1
Natural leather is pasted onto the surface of the material.

In FIG. 2, 3 is a female mold, in which the prototype 1 is placed in an appropriate frame, and a soft material such as silicone resin is poured onto the surface of the prototype 1 to form a surface layer 4 of a predetermined thickness. Next, filler 5 such as epoxy resin is poured into the frame and cured as a whole, and after hardening, the prototype 1
The concave portions 4a and convex portions 4b of the surface layer 4 have an uneven shape that is opposite to that of the original mold 1.

In FIG. 3, reference numeral 6 denotes a syringe needle having a pore 6a as a perforation, and the tip end of the syringe needle is inserted into the surface layer 4 of the female mold 3 from which the mold 1 has been released for a predetermined length. The base end portion 6 is attached so that it protrudes from the surface layer 4. In this case, the position where the injection needle 6 is inserted is preferably a portion corresponding to the convex portion 4b where a ventilation hole is desired to be formed in the cavity, which will be described later. The injection needle 6 is made of stainless steel and has a connecting portion 6b at its base end.

In Fig. 4, reference numeral 7 denotes a mother mold for electroforming, which is made by sequentially adhering mold constituent materials such as epoxy resin to the outer surface of the surface layer 4 of the female mold 3 and laminating them to a predetermined thickness to form a surface layer. 8 and then filled with a porous filler 9 such as so-called aluminum grit made by kneading aluminum powder into a pumice shape, and the connecting portion 6b at the proximal end of the injection needle 6 is formed by filling the matrix 7. Material 9
It is buried inside. Then, the mother mold 7 manufactured in this way is released from the surface layer 4 of the female mold 3 after the skin 8 and the filler 9 have solidified, but at this time, the injection needle 6 is not integrated into the mother mold 7. Then, it is extracted from the surface layer 4 of the female mold 3. In this case, since the surface layer 4 of the female die 3 is formed of a soft material, even if the die-cutting direction of the mother die 7 and the pointing direction of the injection needle 6 do not match, the surface layer 4 and the injection The elastic deformation of each needle 6 causes the injection needle 6 to be pulled out of the surface layer 4 and thus the female mold 3
The mother die 7 that has been cut out has a state in which each of the tips of the injection needles 6 protrudes outward by a predetermined length from the surface thereof (see FIG. 5). The injection needle 6 protruding from the surface of the mother mold 7 that has been cut out from the female mold 3 in this way is cut so as to be flush with the surface of the mother mold 7 (see Figs. 6 and 7). reference). Furthermore, the uneven shapes of the convex portions 7a and concave portions 7b on the surface of the mother mold 7 are opposite to those of the female mold 3 and match the shape of the master mold 1, and the cut ends of each injection needle 6 are located in the concave portions 7b. ing.

The surface of the skin 8 of the mother mold 7 released from the female mold 3 as described above is subjected to conductive processing, as is well known, and then electroformed in an electroforming bath. For example, nickel is deposited and electrodeposited on the surface of the matrix 7, but at this time the filler 9 of the matrix 7
An air pipe is connected to the air pipe, compressed air is supplied into the filling material 9 through the air pipe, and the compressed air is discharged to the surface side of the matrix 7 through the filling material 9 and the pore 6a of the injection needle 6. Ru. In this way, the pore 6
Since the air discharged from a prevents nickel from being electrodeposited on the surface of the matrix 7, nickel is deposited on the surface of the matrix 7 to a predetermined thickness except for the areas corresponding to the pores 6a. Then, a cavity 10 is formed, and a ventilation hole 11 corresponding to the pore 6a is formed in the cavity 10 during electroforming (see FIG. 8).

After the mother mold 10 is formed in this manner, the mother mold 7 is heated to soften it or melted by chemical treatment, and then released from the cavity 10 (see FIGS. 9 and 10). In this case, the shape of the concave portion 10a and the convex portion 10b of the cavity 10 is opposite to the concave-convex shape of the master mold 1 and the mother mold 7, and has a concave-convex shape that matches the female mold 3, and the vent hole 11 corresponds to the convex portion 11b. It penetrates the cavity 10 at the position. The cavity 10 manufactured in this way is set in a mold frame (not shown) and used as a mold for various moldings, but when used in a mold with high molding pressure such as injection molding, the back side of the cavity 10 is After forming a porous layer on the surface, it is lined with a filler such as synthetic resin or zinc.
The vent hole 11 is communicated with the atmosphere or a suction device through the porous layer described above, and when used in a mold with low molding pressure such as vacuum forming or blow molding, the vent hole 11 is connected to the back side of the cavity 10. 11 may be directly connected to the atmosphere or a suction device.

According to the above configuration, the vent hole 11 can be formed in the cavity 10 by a simple operation of discharging compressed air from the pore 6a of the injection needle 6 penetrating the matrix 7 during electroforming. Machining is much easier than drilling holes with a drill after electroforming. In addition, the position of the ventilation hole 11 is determined by inserting the injection needle 6 into the surface layer 4 of the female mold 3 at a position corresponding to the protrusion 4b.
The air hole 11 is located above the convex portion 10b of 0, and the vent hole 11 matches the concave portion of the molded product, and is located at an inconspicuous position on the molded product, making it possible to make the external shape of the molded product extremely good.

Note that the filler 9 attached to the skin 8 of the matrix 7 is omitted, and instead, a hollow cover is attached to the back side of the matrix 7 by, for example, adhesive, and compressed air is supplied into the cover. The injection needle 6 may be discharged from the pore 6a by pumping the electrolyte in the electroformed layer into the cover instead of compressed air.
The electrolyte may be caused to flow out from a,
Furthermore, connect the inside of the cover to the suction side of the pump, and open the pore 6.
The electrolyte may be sucked into the cover from the surface side of the matrix 7 through the pores 6a, or the electrolyte may be sucked into or discharged from the pores 6a instead of compressed air. Electrodeposition of nickel at the corresponding positions is prevented, and the vent holes 10 can be formed in the same manner.

Further, in the above embodiment, the pore 6a as a perforation passing through the mother mold 7 was formed by piercing the surface layer 4 of the female mold 3 with the injection needle 6, but instead of the injection needle 6, a stainless steel cylinder was used. It is also possible to pierce the body into the surface layer 4 and then perform the same process as described above.

Furthermore, a mother mold 7 is manufactured without inserting the injection needle 6 into the surface layer 4 of the female mold 3, and after the mother mold 7 is released from the female mold 3, a hole is punched using a normal drill or a laser. forming a perforation in the matrix 7 by
Thereafter, the ventilation hole 1 was opened by the same operation as in the embodiment described above.
1 may be formed. In this case, the hole opening position relative to the mother die 7 is a position corresponding to the recess 7b, and therefore positional deviation is prevented as much as possible even when the hole is drilled with a small diameter drill, and the ventilation hole formed in the cavity 10 is 1
Position 1 can be reliably matched with the recess of the molded product, and can be easily set at a position where the outer shape of the molded product is not noticeable.

As is clear from the above description, the present invention is an electroforming method that allows small-diameter ventilation holes to be easily formed at positions corresponding to the convex portions of the cavity, and that allows the molded product to have a good outer diameter. It is possible to provide a method for manufacturing a molded product produced by processing.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIGS. 1 to 6 and 8 are longitudinal sectional views showing the manufacturing process of the mold, and FIG. 7 shows the main part of FIG. 6. An enlarged cross-sectional view, Figure 9 is a longitudinal cross-sectional view of the mold, and Figure 10 is a vertical cross-sectional view of the mold.
The figure is an enlarged sectional view of the main part of the mold. In the drawings, 1 is the original mold, 3 is the female mold, 4 is the surface layer, and 6
is the injection needle (ventilation body), 6a is the pore, 7 is the matrix,
8 is the cavity.

Claims (1)

[Claims] 1. A step of manufacturing a mother mold for electroforming having an uneven shape on the surface opposite to that of the cavity, a step of forming a hole penetrating the mother mold at the same time as or after the above step, and a step of forming a hole through the mother mold. is immersed in an electroforming tank and discharged gas or electrolyte onto the surface side of the mother mold through the perforations, or while inhaling electrolyte from the surface side of the mother mold through the perforations. A method for manufacturing a mold manufactured by electroforming, comprising the steps of depositing an electroformed metal layer on the surface to a predetermined thickness and manufacturing a cavity having ventilation holes corresponding to the perforations.