JPH0259875B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention produces a mold by iron electroforming. The present invention relates to an electroforming bath for iron electroforming, a method for manufacturing a mold by iron electroforming, and an iron electroforming apparatus.

[Conventional technology]

Conventionally, most of the molds for molding plastic etc.
Manufactured by machining steel materials.

In addition, electroforming is a method that faithfully reproduces the surface of the original mold, and it is well known that if the finishing condition of the original mold is good, it is possible to manufacture a mold with that good surface condition. As methods for manufacturing molds using electroforming, there have been methods using copper and nickel, and copper and nickel electroformed products have been manufactured and used.

Furthermore, conventionally used iron plating baths include sulfate baths, chloride baths, mixed baths, boron/fluoride baths, and sulfamic acid baths ("Metsuki Kyohon" by Shozo Mizumoto, published by Nikkan Kogyo Shimbun), (1986, p. 138), and it is possible to perform iron electroforming using these iron plating baths.

[Problem to be solved by the invention]

With conventional machining of steel materials, products with simple shapes can be easily manufactured, but products with complex shapes or curved surfaces are difficult to manufacture, and curved parts require manual labor. The disadvantage is that the finishing process requires a long time, and in some cases, the desired surface shape may not be achieved.

In addition, copper electroformed products using the electroforming process often lack hardness and cannot withstand working pressure, and nickel electroformed products have a hardness close to that of steel, but internal stress is generated during electrodeposition. Since the internal stress remains, there is a drawback that the material deforms when it is peeled off from the original mold when it is made into a mold. Therefore, if a sulfur compound is added to the nickel electroforming bath in order to reduce the internal stress in the case of nickel electroformed products, this defect can be removed, but a trace amount of sulfur may be present in the produced nickel electroformed product. It has the disadvantage that it remains interposed, becomes brittle when heated, and breaks when used repeatedly as a mold.

Furthermore, iron electroformed products using conventional iron plating baths do not have desirable physical properties such as high hardness, pressure resistance, and no risk of high-temperature embrittlement in any of the above-mentioned plating baths. If each plating bath is used for a long time, divalent iron is oxidized to trivalent iron, making electroforming work difficult. Additionally, in general, when electroplating is performed for a long period of time, the bath composition at the interface of the plated object changes, causing the plating condition to deteriorate in some areas. Normally, electrolysis is stopped midway through, the item is removed from the bath, and unevenness caused by differences in plating thickness caused by poor plating in some areas is cut off.
There is a drawback that it requires finishing processing, which is removed by mechanical processing such as polishing.

The present invention provides an iron electroforming bath for obtaining iron electroformed products having good physical properties by eliminating the above-mentioned drawbacks, a method for manufacturing molds by iron electroforming using the electroforming bath, and an electroforming apparatus therefor. The purpose is to provide.

[Means to solve the problem]

In order to achieve the above objective, as a result of intensive research, we added fluoride or borofluoride to ferrous chloride and ferrous sulfide as chloride and sulfate, respectively, to remove the harmful effects of trivalent iron. Ascorbic acid or formic acid is added to prevent the oxidation of divalent iron to trivalent iron, and citric acid or pyrogallol is added as a reducing agent to return trivalent iron to divalent iron. An iron electroforming bath (iron plating bath) is used, and a work frame is attached to an iron frame installed on the side of the electroforming mother mold, and the upper part of the work frame is swingably supported on a beam above the electroforming bath. The work frame is lifted out of the electroforming bath in a rocking manner every 5 to 10 minutes. At this time, a hoist is installed on the side of the electroforming bath as a device for lifting the work frame, which is pivotably supported above, in an oscillating manner, and by hoisting up the rope attached to the underside of the work frame,
It is designed to be raised above the electroforming bath in an oscillating manner.

[Effect]

As described above, the present invention provides an agent for removing the harmful effects of trivalent iron, an antioxidant for converting divalent iron to trivalent iron, and a reducing agent for trivalent iron to divalent iron in an iron electroforming bath. Because of the addition of trivalent iron, trivalent iron does not have a negative effect on the electrodeposition of iron, and because it is electrodeposited uniformly, the strength of the electrodeposition is strong, and there is little internal stress generated during electrodeposition. There is no residual internal stress in the iron electroformed product.

Also, every 5 to 10 minutes during electroforming, the work frame to which the electroform mother mold is attached is lifted out of the electroforming bath by swinging as shown in Figure 6, so that the work frame comes out of the bath. When the electrolysis is interrupted, the deteriorated electroforming solution adhering to all the interfaces of the electrodepositing surface of the electroforming mother mold falls onto the electroforming bath and is removed, and the work frame is rocked again and poured into the bath. When returned, the electrodeposition interface of the electroforming mother mold is replaced with a new electroforming solution, and the uniformity of the interface can be restored, making it possible to perform electrodeposition with a uniform thickness even during long-term work, and compared to conventional methods. There is no need to stop electrolysis during electroforming and perform finishing processes such as cutting and polishing.

〔Example〕

Reference will now be made in detail to the accompanying drawings, which illustrate one example of carrying out the invention.

This example shows the process of manufacturing a mold used for plastic molding, etc. A mold for blow molding usually consists of a pair of upper and lower molds divided into two parts, but the manufacturing method Since they are the same, only one type will be explained below.

Reference numeral 1 is a prototype, which is made of a wooden mold or plaster, and has the same external shape as the molded product to be molded from plastic or the like. 2
is an iron frame installed on the master mold 1, and is an enclosure for pouring resin or plaster onto the upper surface of the master mold 1. 3 is a replica made by pouring resin or plaster onto the top surface of outer model 1, and is a transfer of model 1. Since direct electroforming using the wooden pattern of model 1 is not possible, it is used as a waste mold. The uneven surface parts 3A, 3 are prepared and are the opposite of the original model 1.
B. 4 is an iron frame installed on the uneven surfaces 3A and 3B of the replica 3;
After applying a mold release agent such as wax to 3B, a layer of epoxy resin and glass cloth is formed on top of it.
It serves as an enclosure for producing the electroforming mother mold 5 and also as a fixture for attaching the electroforming mother mold 5 to a work frame 7, which will be described later. 6 is a conductive layer made of a conductive film made by known nickel or iron plating;
This is applied to the uneven surface portions 5A and 5B of the electroforming mother mold 5 which is the same as the master mold 1 extracted from A and 3B, and is electrically continuous with the iron frame 4 on the side surface of the electroforming mother mold 5. 7 is a work frame attached to the tip of the iron frame 4 (bottom end in Figure 3), and the tips on both sides are attached to the electroforming mother mold 5.
The uneven surface portions 5A and 5B are extended upward. 8 is an anode, and the uneven surface portions 5A, 5 of the electroforming mother mold 5
They are set above B with appropriate spacing. Reference numeral 9 denotes a DC power source, the positive electrode of which is connected to the anode 8 and the negative electrode connected to the work frame 7, respectively. Reference numeral 10 denotes a beam installed above the electroforming tank (plating tank) 12, and the upper part of the work frame 7 is swingably supported on the right side of the center of the beam 10 as shown in FIG. The electroforming mother mold 5 and anode 8 set in the mold are suspended. 11 is a wire rope for hoisting and electroforming tank 12
A hoisting machine installed on the left side of the electroforming tank 12 through a pulley 17 with one end fixed to an elevating body 16 mounted on a post 15 established on the left side of the electroforming tank 15 so as to be able to rise and fall freely, and the other end attached to the tip of the post 15. 18 winding drums 1
9, wound onto the drum 19, and rewound. 13 is an iron electroforming bath, the bath composition of which is 220 g of ferrous chloride, 120 g of ferrous sulfate, and 25 g of sodium fluoride as a remover for removing the harmful effects of trivalent iron, as well as 25 g of divalent iron. Formic acid 5g/as an antioxidant for iron to trivalent iron,
5 g of pyrogallol was added as a reducing agent from trivalent iron to divalent iron. A rope 20 connects the lower end of the work frame 7 and the elevating body 16, and is made of synthetic resin or the like that is resistant to chemicals added to the iron electroforming bath 13 and the like.

Next, when performing electroforming, the surfaces of the iron frame 4 and work frame 7 are masked, and the wire rope 1
1 is wound onto the winding drum 19 in the winding direction 11A, and the work frame 7 on which the electroforming mother mold 5 and the anode 8 are set is pivotably supported on the beam 10 in the state shown in FIG. Winding rope 11 on drum 1
9 in the unwinding direction 11B, and the electroforming tank 12
immersed in the iron electroforming bath 13 as shown in FIG.
Start electroforming. Electroforming (metsuki) at this time
The conditions were a bath temperature of 65°C, a current density of 3A/dm ² , and a pH of 3.5. During electroforming, the control panel 21 automatically operated the winding machine 18 every 5 to 10 minutes to attach the wire rope 11 to the drum 19. Wind it up in the winding direction 11A,
The work frame 7 is lifted from the electroforming bath 13 as shown in FIG. 5, and rewound in the unwinding direction 11B, immersed as shown in FIG. 6, and electroformed again.
After continuous operation for 200 hours, a mold 14 having an average thickness of 4 mm and a cavity 14A having an outer shape opposite to that of the master mold 1 was obtained on the electroforming master mold 5 as shown in FIG. Note that the electroforming work is completed by separating the mold 14 from the electroforming mother mold 5.

〔Effect of the invention〕

The present invention has the above configuration, and when electroforming is performed using the iron electroforming bath of the present invention, an iron electroformed product having desirable physical properties can be obtained.

In addition, it is possible to obtain adhesive 14 for iron electroformed products that is uniform and thick using an extremely simple method.
It is possible to provide an extremely effective method for manufacturing molds using iron electroforming.

Furthermore, the work frame in which the electroforming mother mold 5 and anode 8 have been set is immersed in the electroforming bath 13 every 5 to 10 minutes during the electroforming process using the control panel 21 as shown in FIG. As shown in the figure, the work frame 7 is lifted sideways from the electroforming bath 13 by swinging.
When the work frame 7 is lifted, the electrolysis is interrupted and the deteriorated electroforming liquid on all the interfaces of the electrodeposition surface falls as droplets 22 and is removed as shown in FIG.
When the work frame 7 is returned to the bath 13, the electrolysis is restarted and the electrodeposition interface is replaced with a new electroforming solution. When the electrolysis starts, new crystal nuclei are generated and the surface is made uniform. Since uniform electrodeposition is possible, there is no need to stop the conventional electroforming process and perform finishing processes such as cutting and polishing by machines or by hand.

[Brief explanation of drawings]

The attached drawings show an example of the implementation of the present invention.
Figure 1 is a sectional view of the main part of the original model, Figure 2 is a sectional view of the main part of the replica, Figure 3 is a sectional view of the main part of the electroformed mother mold with a conductive layer applied, and Figure 4 is the electroformed mother mold. A front view partially cut away with the work frame and anode set,
Figure 5 is a partially sectional front view of the work frame immersed in the electroforming bath, Figure 6 is the front view of the work frame lifted from the electroforming bath, and Figure 7 is the electroforming mother mold. FIG. 8 is a cross-sectional view of the main part in a state where a mold is manufactured on top, and FIG. 8 is a cross-sectional view of the main part in a state where the mold is peeled off from the electroforming mother mold. 1...Prototype, 2...Iron frame, 3...Replica, 3
A...Concave part, 3B...Convex part, 4...Iron frame, 5
... Electroforming mother mold, 5A ... Concave surface part, 5B ... Convex surface part, 6 ... Conductive layer, 7 ... Work frame, 8 ... Anode,
9...DC power supply, 10...Beam, 11...Wire rope for hoisting, 11A...Hoisting direction, 11B
... Unwinding direction, 12 ... Electroforming bath, 13 ... Iron electroforming bath, 14 ... Mold, 14A ... Cavity,
15... Support column, 16... Lifting body, 17... Pulley,
18... Winding machine, 19... Winding drum, 20
...Rope, 21...Control panel, 22...Droplet.

Claims (1)

[Claims] 1. Ferrous chloride 150-300g/, ferrous sulfate 50-300g/
200 g/and 5 to 50 g/of sodium fluoride or borosodium fluoride or borosulfur ammonium fluoride to remove the adverse effects of trivalent iron.
For iron electroforming characterized by adding ascorbic acid 0.5 to 5 g/or formic acid 1 to 10 g for oxidation prevention/citric acid 5 to 50 g/or pyrogallol 0.1 to 10 g/as other organic reducing agents. electroforming bath. 2. Create an original form with the same external shape as the molded product using a wooden mold or plaster, install an iron frame on the original form, pour resin or plaster to create a replica, and place the iron frame on top of the replica. After applying a mold release agent such as wax to the concave part of the replica that is opposite to the original model, an electroforming mother mold with a layer of epoxy resin and glass cloth is created, and a conductive material is applied to the surface of the electroforming mother mold. A conductive layer of a conductive film is prepared, a work frame is attached to the iron frame on the replica, an anode is set with an appropriate distance between it and the electroforming mother mold, the iron frame and the work frame are masked, and the work frame is placed on the replica. The anode and the work frame are each connected to a power source and immersed in the electroforming bath for iron electroforming according to claim 1, at a bath temperature of 50 to 80°C and a current density of 1 to 15 A/d.
^2. A method for manufacturing a mold by iron electroforming, characterized in that electroforming is performed at a pH of 3.0 to 4.0, and the work frame is lifted from the electroforming bath in an oscillating manner every 5 to 10 minutes. 3. A beam is provided above the electroforming bath, the upper part of the work frame according to claim 2 is pivotably supported on the beam, a hoist is installed on the side of the electroforming bath, and the lower surface of the work frame is provided with a hoist. 5~
An electroforming device that is characterized by lifting the work frame from the electroforming bath in a oscillating manner by winding it up every 10 minutes.