JPS591209A - Molding die - Google Patents

Abstract

PURPOSE:To improve precision in shape of a die by making up an electroformed cavity or core of a sandwich structure that a copper layer is provided between a pair of nickel layers to reduce shrinkage caused at removal of a matrix. CONSTITUTION:A matrix 1 composed of aluminium and an alloy thereof is held in a plating tank 4 storing plating liquid L and connected with a cathode of DC power source to be plated with nickel to form a nickel layer 5. The lst nickel layer 5 is plated with copper to obtain an electroformed copper layer 6 with a thickness 4-20mm. and nickel is plated again on this copper layer 6 to obtain another electroformed nickel layer 7 with a thickness about 0.5-1omega. The magor part of this cavity is made up of copper 6 and thereby smaller in electroforming stress than when the whole is formed of nickel. Accordingly, when the matrix 1 is removed, shrinkage is small and precision is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Summary of the Invention] The present invention relates to a molding die in which a cavity and a core provided in a template are formed by electroforming.

[Technical background of the invention and its problems]

When the shape of the cavity or core is complex, they are formed by electroforming, which is easier to manufacture than cutting. When forming cavities and cores by electroforming, these are molded into a matrix made of aluminum or its alloys.
It is manufactured by electroforming a steel plate that has almost the same thermal conductivity and coefficient of thermal expansion as the above-mentioned iron template.

By the way, when electroforming a second layer on a matrix, the electrodeposition stress of the second layer is extremely large. Therefore, when the second kel is deposited on the mother mold and then the second kel is removed from the second kel mass, the cavity or core formed in the nickel ring, which has the opposite shape of the mother mold, shrinks and its shape accuracy becomes sufficient. The problem was that I couldn't get it. Further, the electrodeposition stress of Kel is proportional to the thickness deposited on the matrix. However, since the above-mentioned cavity (or core) must be provided by being embedded in a template, it is necessary to deposit it thickly in order to obtain the strength, and this also increases the shrinkage of the cavity or core. Something happened.

[Purpose of the invention]

In this invention, by forming the cavity or core mainly from steel, large electrodeposition stress is not generated.
It is an object of the present invention to provide a molding die that has sufficient strength to be installed on a template.

[Summary of the invention]

By making the cavity or core formed by electroforming into a structure with a copper layer between a pair of two layers, the nickel layer provides strength, and the steel layer reduces the overall electrodeposition stress. It was designed to reduce the

[Embodiments of the invention]

Hereinafter, an embodiment of the present invention will be described with respect to forming a cavity shown in the drawings. In the figure, 1 is a matrix made of aluminum or its alloy. This mother mold 1 has a gear v3 formed on one end side of the shaft body 2. Such a mother die 1 is held in a plating bath 4 containing a plating liquid and connected to the cathode of a DC power source. Then, this mother mold 1 is first subjected to bilayer plating, and a first bilayer layer 5 having a thickness of about 0.2 to 0.5 mm is electroformed. Next, this first two-layer layer 5 is plated with copper, and a copper layer 6 with a thickness of about 4 to 20 cm is electroformed, and then this copper layer 6 is plated with nickel again to reduce the thickness. Second nickel layer 7 of about 0.5 to 1 m+
A plurality of rods 9 for electroforming are inserted along the circumferential direction of the copper layer 6.

Once the electroformed ingot 10 consisting of the first nickel layer 5, copper layer 6, and second nickel layer 7 is deposited on the mother mold 1 in this way, this electroformed ingot 1o is cut into a predetermined shape. By processing and removing the mother mold 1 by melting it with, for example, an NmOH solution, a cavity 11 having a shape opposite to that of the gear 3 of the mother mold 1 is obtained. Then, this cavity 11 is embedded in the mounting hole 13 of the template 12 as shown in FIG.

In the cavity 11 configured in this manner, most of the capacitance 11 is made up of the copper layer 6, so that the electrodeposition stress is smaller than that in the case where the entire capacitance 11 is made of nickel. Therefore, electroformed ingot 10
Since the shrinkage when the matrix 1 is removed from the mold is also reduced, a highly accurate cavity 11 can be obtained. In addition, since copper has a faster precipitation rate during electroforming than nickel, the electroformed ingot 1
0 can be efficiently formed.

Further, the part of the cavity 11 that contacts the resin having the opposite shape to the gear 3 is formed by the first nickel layer 5, and the part that contacts the mounting hole 13 of the template 12 is formed by the second nickel layer 5.
Second, since it is formed by the Kel layer 7, it has sufficient strength during molding and when embedding into the template 12. Moreover, since the reinforcing rod 9 is inserted into the copper layer 6, the reinforcing rod 9 provides sufficient strength to the copper layer 6 against the force applied to the copper layer 6 when the mold is opened and closed or when the mold is clamped. Moreover, since the copper layer 6 has a high thermal conductivity, it is difficult to dissipate the heat applied to the cavity 11 to the template 12 well. Since it has good affinity with the second nickel layer 5.7, the above-mentioned first nickel layer 5.7 can be applied under repeated stress. There is no possibility of separation from the second two layers 5 and 7.

Incidentally, in the above embodiment, a cavity was described, but it is clear that similar effects can be obtained by applying the present invention to a core.

〔Effect of the invention〕

As described above, in this invention, the cavity or core formed by electroforming has a structure in which a steel layer is provided between a pair of two-layer layers. Since the electrodeposition stress during electroforming is lower than that in the case of electroforming, there is less shrinkage when removing the matrix, improving shape accuracy. In addition, since copper can be electroformed at a higher speed than nickel, the production efficiency can be improved by having a copper layer, and since the copper layer has high thermal conductivity, the cavity or core can be cooled well. It has the following advantages.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and Fig. 1 is a side view of the mother mold, Fig. 2 is an explanatory diagram when electroforming is performed on the mother mold, and Fig. 3 is a diagram showing the state in which the cavity is cut into the template. FIG. 5... First nickel layer, 6... Copper layer, 7... Second Kel layer, 9... Reinforcement rod, 11... Capity, 12... Template.

Claims (2)

[Claims] (1) A molding die in which a cavity or core formed by electroforming is provided on a template. The molding die is characterized in that the cavity or core has a structure in which a copper layer is provided between a pair of two-layer layers. (2) The molding die according to claim 1, wherein a reinforcing hole is inserted into the copper layer.