JPH0124877B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field of interest] This invention relates to an electroforming mold and a method for manufacturing the same.

"Prior Art" The surface of a mother core for forming an electroformed mother mold generally has a complicated shape, and therefore precision is required even though machining is difficult. Therefore, an electroformed mother mold is obtained by plating the surface of the mother core, but due to its nature, it takes a considerable amount of time to plate the uneven portions formed on the surface. In other words, uneven areas are plated at a low current density and over a long period of time, and when the surface of this plating layer becomes smooth, the current density is increased again to form a reinforcing plating layer at high speed. However, the plating layer for reinforcement is generally about 10-odd millimeters thick, and it has the disadvantage that it takes several days to more than 10-odd days to plating that thickness.

"Purpose" This invention takes into account the drawbacks of the conventional technology,
The purpose is to form a reinforcing frame with the required thickness in a short time.

"Summary" In order to achieve the object, the present invention smoothes the uneven portions formed on the surface of the base core by plating, and in this state, fits a metal reinforcing frame around the outer periphery of the base core, and furthermore, The base core and reinforcing frame are integrated by plating the surface.

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

That is, in FIGS. 1 and 2, the mother core 1 is formed by machining an aluminum material, for example, and has a large number of recesses 2 and protrusions 3 on its outer peripheral surface. For example, if the core 1 is a pinion gear, an uneven portion consisting of peaks and valleys is formed on its outer periphery.

First of all, on the surface of this core, there are especially uneven parts 2,
Apply plating to a predetermined thickness so as to cover 3. This plating is performed slowly with a low current density and over a sufficient period of time. This makes the first
A plating layer 5 is formed, and the uneven portions 2 and 3 are smoothly covered with this first plating layer. However, the surface of the first plating layer 5 is not necessarily linear in its cross section, that is, it is difficult to have a uniform outer diameter over its entire surface.

Next, it has an inner diameter approximately equal to the outer diameter of this core,
And the length in the axial direction, that is, the thickness is the base core 1
A metal reinforcing frame 7 that is shorter than the length in the axial direction is prepared, and the mother core on which the first plating layer 5 has been ground is fitted into this metal reinforcing frame by press-fitting or insertion.
The outer diameter of the metal reinforcing frame 7 is set to be 1 to 3 mm smaller than the preset finished dimension. Further, on a surface of the metal reinforcing frame that intersects with the base core 1, a curved portion 8 is formed at a corner formed together with the base core to smoothly connect the two to each other with a predetermined radius.

Further, in the fitted state of the metal reinforcing frame 7 and the base core 1, plating is applied over the entire surface thereof until a predetermined thickness, for example, 1 to 3 mm is reached. A second plating layer 9 is thereby formed. At this time, the curved portion 8 makes the electrodeposition smooth during plating. In other words, by making the corner formed by the base core 1 and the metal reinforcing frame 7 as small as possible, the current density is not reduced. Although it varies slightly depending on the size, it is preferably about 0.2 to 20.

Next, both sides of the metal reinforcing frame 7 and the base core 1 that intersect with their respective axis lines are cut using a lathe as shown in FIG.
Grind along the A line to a predetermined dimension. That is, the second plating layer 9 formed on both sides of the metal reinforcing frame 7 and the core 1 are ground until the core itself, that is, the aluminum core material is exposed.

Subsequently, when this mother core is immersed together with the metal reinforcing frame 7 in a caustic soda solution, only the mother core 1, that is, the aluminum core material melts, and the metal reinforcing frame 7 melts.
A female mold having the same shape as the mother core 1 is formed inside the mother core 1, thereby completing the electroforming mother mold.

``Effects'' As described above, this invention involves applying plating to a predetermined thickness of a mother core having an uneven surface so as to cover the uneven portion, and then grinding the surface. The core is fitted into the metal reinforcing frame, and plating is applied to the surfaces of the metal reinforcing frame and the mother core in the fitted state until a predetermined thickness is reached, so that the electroforming mother mold can be formed easily. This can be done in a very short period of time. For example, if the thickness of the metal reinforcement frame is 10 mm, the plating deposition rate per day is 1.
In the case of mm, the time required to complete the electroforming mold can be reduced by about 10 days. Furthermore, when considering the rotation rate of the plating layer, the wear and tear of the electrodes, and the power consumption, etc., there is an advantage that it is more economical than the processing cost of the metal reinforcing frame.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the manufacturing process of the electroforming mold of the present invention, FIG. 2 is a front sectional view,
FIG. 3 is an enlarged sectional view of the corner between the core and the metal reinforcing frame. 1... Mother core, 2... Concave portion, 3... Convex portion, 5...
First plating layer, 6... Support shaft, 7... Metal reinforcing frame, 8... Curved portion, 9... Second plating layer.

Claims (1)

[Scope of Claims] 1. After applying plating to a predetermined thickness on a mother core having an uneven surface so as to cover the uneven portion, the surface is ground, and then the ground core is made of metal. A method for manufacturing an electroforming mother mold, which is fitted into a reinforcing frame, and further plating is applied to the surfaces of the metal reinforcing frame and the mother core in the fitted state until a predetermined thickness is reached. 2. The electroformed motherboard according to claim 1, wherein the outer dimensions of the metal reinforcing frame are formed in advance to be smaller than the finished dimensions by a predetermined dimension, and the plating is applied to the surface thereof until the finished dimensions are reached. Mold manufacturing method. 3. A first plating layer applied to a base core having an uneven surface and covering the irregularity with a predetermined thickness, and a metal reinforcing frame into which the base core is fitted through the first plating layer. and a second plating layer formed on the surfaces of the metal reinforcing frame and the mother core in a fitted state. 4 The length of the core in the axial direction is set longer than the length of the metal reinforcing frame in the axial direction, and
Claim 3: On a surface of the metal reinforcing frame that intersects with the base core, a curved portion is formed at a corner formed together with the base core to smoothly connect the two to each other with a predetermined radius. Electroformed mother mold described in section.