BACKGROUND ART Conventionally, after an electroforming member is formed, it is cut at a predetermined length by a mechanical process. It was general that the cut electroforming member has a desired sectional shape such as a conical shape through a mechanical process. However, it is difficult to efficiently cut the electroforming member having an outer diameter of. several microns or several tens of microns. In the present invention, an electroforming member is formed using a core material, and a nonconductive section is formed in the core material to

efficiently cut the electroforming member and obtain its sectional shape. The electroforming member has an outer diameter of several microns to several tens of microns, several hundreds of microns or several thousands of microns. The electroforming member does not necessarily depend on ultrafine diameters. The thick diameter of the electroforming member will be within the range of the present invention.

It is difficult for an electroforming member having an outer diameter of several microns, several tens of microns or several hundreds of microns to obtain a stepped form by the conventional mechanical process. However, in the present invention, such a stepped form can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

In the drawings: FIG. 1 illustrates an electroforming process according to the present invention ; FIG. 2 illustrates a ferrule ; FIG. 3 illustrates a covering process of a forming material and a coating process of a conductive material; FIG. 4 illustrates an electroforming member manufactured by forming an electroforming layer on a conductive metal coating layer ; FIG. 5 illustrates a process of removing a core material from an electroforming member ; FIG. 6 illustrates the state that a forming material

and a conductive material are chemically removed from the electroforming member; FIG. 7 illustrates an electroforming member having various shapes formed of different kinds of metal layers ; FIG. 8 is an example of a core material having a nonconductive section; FIG. 9 illustrates an electroforming process performed in a core material having a nonconductive section; FIG. 10 illustrates an electroforming member formed in a core material having a nonconductive section; FIG. 11 is an example of a nonconductive section formed at both ends of the electroforming member; FIG. 12 is an example of a nonconductive section having lower and upper sections; FIG. 13 illustrates a nonconductive section formed in a die; FIG. 14 illustrates a process of manufacturing a cut electroforming member having a stepped form ; FIG. 15 illustrates a process of manufacturing a cut electroforming member having an inclined stepped form; and FIG. 16 illustrates a perspective view and a sectional view of the electroforming member of FIG. 15.

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL PROBLEMS There is a problem in that considerably inconvenient work is needed to cut the electroforming member having a fine diameter at a predetermined size by a conventional mechanical process. There is also problem in the conventional mechanical process in that more considerably inconvenient work is needed to allow the cut electroforming member to obtain a predetermined sectional

shape at its both ends. However, in the present invention, a nonconductive section is formed in a core material and an electroforming member is cut at a predetermined size by the nonconductive section. Also, the electroforming member can obtain a desired sectional shape. In the present invention, mass production of the cut electroforming member can be achieved at precise and exact dimensions.

The conventional electroforming member made by the mechanical process has drawbacks in that processing precision cannot be obtained and a processed sectional portion is not clear due to a processing chip. This reduces processing efficiency. Further, in the present invention, a stepped form can be obtained in the cut electroforming member.

TECHNICAL SOLUTIONS Accordingly, the present invention is directed to a method of manufacturing a cut electroforming member which has a stepped form and a cut electroforming member which has a stepped form made by it that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.

An object of the present invention is to provide a method of manufacturing a cut electroforming member which has a stepped form and a cut electroforming member which has a stepped form made by it, in which an electroforming process is performed in an electroforming tub by connecting a negative electrode to a core material having a nonconductive section and a positive electrode to a melted metal.

Another object of the present invention is to provide a method of manufacturing a cut electroforming member which has a stepped form and a cut electroforming member

which has a stepped form made by it, in which the electroforming member is cut at a predetermined length by a nonconductive section and has a stepped form.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the scheme particularly pointed out in the written description and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, in a method of manufacturing a cut electroforming member including the steps of performing an electroforming process in an electroforming tub by connecting a negative electrode to a core material having a nonconductive section and a positive electrode to a melted metal, and cutting the electroforming member at a predetermined length by the nonconductive section, wherein a stepped form is obtained in the cut electroforming member.

In the present invention, a desired sectional shape for the electroforming member is formed at one end or both ends of the nonconductive section. In this case, the shape of the end of the nonconductive section is imprinted on the end of the cut electroforming member. The nonconductive section may be divided into an upper section and a lower section, and may be made by injecting a liquid material into its die and hardening it.

In the present invention, the core material is covered with a forming material. To obtain a stepped form in the cut electroforming member of the present invention,

a nonconductive portion may be formed using a photoresist or an ultraviolet hardening section hardened by ultraviolet rays may be formed. Alternatively, a solid type nonconductive shape portion may be formed in the cut electroforming member to obtain a stepped form. The solid type nonconductive shape portion may have an inclined stepped form.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a method of manufacturing a cut electroforming member and a cut electroforming member made by it, in which an electroforming process is performed in an electroforming tub by connecting a negative electrode to a core material having a nonconductive section and a positive electrode to a melted metal. In the present invention, an electroforming member is cut at a predetermined length by the nonconductive section. A desired sectional shape is formed at one end or both ends of the nonconductive section and an electroforming process is performed. Thus, the shape of the end of the nonconductive section is imprinted on the end of the cut electroforming member. The nonconductive section may be divided into an upper section and a lower section, and may be made by injecting a liquid material into its die and hardening it.

In the present invention, the core material can be covered with a forming material. The core material has three types in the present invention. First, the core material may be of a conductive material. Second, the core material may be formed in such a manner that it is covered with a forming material and. the forming material is thinly coated with a conductive material. Finally, the core material may be of a nonconductive material so that the

nonconductive core material is thinly coated with a conductive material. In the present invention, the core material is defined as any one of the above types.

The forming material is kept in a die at a melted state or a partially melted state and is covered on the core material when the core material passes through the die. The forming material is thinly coated with a conductive material after it is hardened. An electroforming layer is formed by connecting a negative electrode to the conductive coating portion and performing an electroforming process in an electroforming tub. The core material in the electroforming member is removed by a drawing process. The inside of the electroforming member is then washed.

The forming material is softened at a temperature of 100°C or less, or is contracted with the lapse of time to remove the core material. The forming material includes resin and a low temperature heat melting material. The low temperature heat melting material is softened at a temperature of 100°C or less. The low temperature heat melting material includes at least one of resin, pitch and wax. The resin is thermoplastic or thermosetting resin. An example of the resin includes epoxy resin. A small content of silicon may be added to the forming material to improve hetero-characteristics. The coated conductive material is thinly formed on the forming material by vacuum deposition.

The coated conductive material is thinly deposited on the forming material by a chemical method.

In the present invention, ferrule that is a connecting member of an optical cable can be manufactured.

The ferrule is formed with one end having a conical shape to easily insert an optical cable therein. In this case, the ferrule has an inner diameter of 125 microns. In the

present invention, the core material is of metal or plastic. Preferably, stainless having strong tension is used as the core material.

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

FIG. 1 illustrates an electroforming process according to the present invention. A metal ion melting solution 300 decomposed in ion state is contained in an electroforming tub 400. An electroforming metal case 100 of nickel, for example, is positioned at one side of the electroforming tub. A positive electrode is connected with the electroforming metal case and a negative electrode is connected with a conductive material 200 to be electroformed. A melted metal ion moves to the surface of the conductive material and is grown as a new electroforming metal layer thereon. This process is called an electroforming process. In the present invention, nickel, copper (Cu), gold (Au), or nickel (Ni) alloy is used as the metal used for electroforming. Other metal that can be electroformed may be used as the metal for electroforming.

FIG. 2 illustrates a ferrule. A ferrule 500 includes an inner through hole 600 having an inner diameter of 125 microns. A conical shaped incline plane 700 is formed at one end of the ferrule and a plane is formed at the other end. The optical cable can easily be inserted into the ferrule through the conical shaped incline plane 700.

FIG. 3 illustrates a covering process of a forming material and a coating process of a conductive material.

It is general that a core material 1 has the size of several microns or several tens of microns. The core material is produced by a drawing process. The core

material processed by drawing has limitation in its cylindrical degree. A number of scratches are generated on the surface of the core material due to the drawing process. In the present invention, the core material 1 is used, so that any effect of the scratches and the incomplete cylindrical degree on the core material is minimized. That is, a die 3 is supplied with the forming material 2 at a melted state or a partially melted state, and the core material 1 is drawn through the die 3 and at the same time is covered with the forming material. The forming material serves to cover damage formed on the core material. The forming material passed through the die 3 has a supplemented cylindrical degree like the shape of the die 3. If the die has a circular shape, the core material is covered with the forming material having a circular shape. If the die has a rectangular shape, the core material is covered with the forming material having a rectangular shape.

In the present invention, it is preferable that the forming material is softened by heat if it is hardened or the forming material is automatically contracted after the lapse of time if it is hardened. An example of the forming material includes mixture of resin and a low temperature heat melting material. In the experiment example, the forming material has been formed by mixing epoxy resin of 60%, resin of 20% as a heat melting material, and silicon of 20% for improving hetero-characteristics. If the core material has a thickness of 50 microns, it can easily be drawn without applying heat. If the core material has a thickness of 150 microns, it can be drawn by applying heat at a temperature of 100°C or less. If the core material has a thin thickness, it is easily removed without applying heat after the lapse of time. This is because

that the forming material is automatically contracted with the lapse of time after it is hardened. In the present invention, a low temperature heat melting material such as pitch or wax may be used instead of resin. The low temperature heat melting material may be made by selectively mixing resin, pitch, and wax. Silicon has been used to increase hetero-characteristics.

In the present invention, the core material 1 has a thickness of several microns or several tens of microns, and the core material of metal or non-metal may be used.

The core material of metal is preferably used because strong tension is required for the core material. An example of the metal core material includes stainless steel. The core material made by a mechanical method has some problems such as defects and scratches caused on its surface and uneven thickness. If the electroforming process is performed in the original core material without covering damage on the surface of the core material with the forming material, the surface roughness of the core material is reflected on the inside of the electroforming member and the core material is engaged with the scratches of the electroforming member. In this case, it is very difficult to remove the core material. However, in the present invention, the core material is uniformly covered with the forming material while being passed through the die. As a result, the scratches on the surface of the core material are all covered with the forming material. The inside of the ultrafine pipe according to the present invention is precisely controlled in its dimensions because the die can be controlled in ultra precision. In the present invention, the forming material is used to minimize poor effect of the core material by covering the core material and to easily remove the core material after

the electroforming member is formed by the electroforming process. Since the forming material is positioned at the boundary between the core material and the electroforming member, the core material is separated from the electroforming member. In the present invention, when the core material is covered with the forming material, it is preferable that the core material is uniformly covered with the forming material with concentricity while passing through the center of the die.

After the core material is covered with the forming material and the forming material is hardened, the forming material is thinly coated with a conductive material. A conductive metal coating layer 4 may thinly be formed on the forming material by vacuum deposition or chemical method. The chemical method means that a metal film is formed by a chemical reaction that extracts chemical silver (Ag) or platinum. In the present invention, various metals such as gold, silver, copper or nickel may be used as the conductive metal. The conductive metal coating layer 4 is coated on the forming material 2 and serves as a conductor that serves to flow negative current during the electroforming process.

FIG. 4 illustrates a pipe manufactured by forming an electroforming layer on the conductive metal coating layer.

An electroforming layer 5 serves as a main body of the ultrafine pipe of the present invention and is formed of electroforming metal such as nickel, nickel alloy or copper. Also, the electroforming layer 5 may be formed by layering different kinds of metals. To form the electroforming layer, melted metal ions move to the conductive metal coating layer by connecting negative electrode to the conductive coating layer and positive electrode to the electroforming metal. The moving metal

ions start to be formed as an electroforming metal film on the surface of the conductive metal coating layer. The thickness of the electroforming metal film is grown with the lapse of time. As a result, the electroforming layer 5 is formed. The thickness of the electroforming layer is within the range of several microns to several tens of microns or several hundreds of microns. The thickness of the electroforming layer may be within the range of several millimeters.

FIG. 5 illustrates the process of removing the core material from the electroforming member. The core material 1 in the electroforming member is removed by a drawing process after the electroforming process is performed. In this case, the core material is not easily removed because it is thin. In the present invention, the forming material 2 coated on the surface of the core material is varied to a fluid state by heat to easily remove the core material.

If the electroforming process is directly performed in the rough core material, it is difficult to remove the core material because the scratches of the core material are engaged with those inside the electroforming member. Also, there is limitation in improving precision because the scratches of the core material are reflected inside the electroforming member as they are. If the core material is physically drawn from the electroforming member, it may be likely to be cut during the drawing process. The inner wall of the electroforming member pipe is damaged when the core material is drawn. This makes the precise process difficult. In this case, the precise mechanical process is again performed to cover the damage of the inner wall of the electroforming member. In the present invention, fluidity is given to the forming material 2 by heating the electroforming member having the core material therein so

that the core material is easily removed from the electroforming member. According to the experiment, if the core material having a small diameter and a short length is covered with the forming material, it is easily removed without applying heat. However, if the core material has a thick outer diameter, it is preferably removed by applying heat thereto. Since the forming material of the present invention is softened by heat even after it is hardened, it can remove the core material. Also, since the forming material is contracted with the lapse of time, it can remove the core material. In this case, heat deformation of the electroforming member can be avoided because the core material is not heated. It is preferable that the forming material is covered with a low temperature heat melting material that is varied to a fluid material at a low temperature below 100°C because high temperature affects the electroforming member.

If the core material is removed, the forming material 2 remaining in the electroforming member is generally removed by a chemical washing process. If the core material is thinly covered with the forming material at a thickness of 2 microns to 7 microns, defects or scratches formed on the surface of the core material are strongly coupled with the forming material. In this case, the forming material and the core material are simultaneously removed in a state that they are integrally coupled with each other. According to the results of the experiment as described above, if the forming material has a thickness of 2 microns to 7 microns, the forming material and the core material are simultaneously removed.

The results of the experiment may depend on characteristics of the forming material. If the forming material 2 is thick, it is removed by a chemical washing

process after the core material is removed. After the core material and the forming material are removed, the conductive material coating layer 4 remaining in the electroforming member is removed by a chemical melting method.

FIG. 6 illustrates the state that the forming material and the conductive material are chemically removed from the electroforming member. The forming material is preferably washed by selecting a solvent easily melted in a chemical material such as petroleum and toluene. The forming material and the conductive material coating layer can be removed by the solvent while vibration of ultrasonic waves during the washing process is generated. The electroforming member of the present invention can be formed of different kinds of metal layers 5a, 5b, and 5c. The metal layers include an intensity layer and a conductive layer depending on characteristics of the respective metal layers.

In the present invention, the electroforming member may have a thin inner diameter 9 and a thick outer diameter 5. In this case, ferrule used as a connecting member of an optical cable can be manufactured.

FIG. 7 illustrates an electroforming member formed of different kinds of metal layers. In the present invention, the electroforming member has various shapes different from a section of the core material using the forming material and the die. That is, the electroforming member can be manufactured in the same shape as that of the die. At this time, different kinds of metal layers of Cu, Ni, and Ag can be formed by varying metal in the electroforming tub.

FIG. 8 is an example of the core material having a nonconductive section. First, a core material 6 having a

nonconductive section may be of a conductive material.

Second, the core material 6 may be formed in such a manner that it is covered with a forming material and the forming material is thinly coated with a conductive material.

Finally, the core material 6 may be of a nonconductive material so that the conductive core material is thinly coated with a conductive material. In the present invention, the core material corresponds to any one of the above types. Referring to FIG. 8, a nonconductive section 7 is formed and separated at several intervals. The nonconductive section 7 may include an end portion having various shapes. As an example, the nonconductive section 7 may include a conically inclined end portion 8 and a plane end portion 10. In the present invention, the nonconductive section is defined as an electrically insulated material formed in the core material and separated at several intervals. An insulating material having elasticity is preferably used as the nonconductive section. More preferably, the insulating material has hetero-characteristics. In this case, a separate hetero- layer is not required. As an example of an insulating material having elasticity and hetero-characteristics, silicon or rubber based material is used in the present invention. Such an insulating material can repeatedly be used. Once the electroforming process is performed, the electroforming member generates stress with the nonconductive section. When the electroforming member is detached from the nonconductive section as the electroforming process is finished, the stress fails to easily detach the electroforming member from the nonconductive section. That is, when the electroforming member is detached from the nonconductive section, the electroforming member affects the nonconductive section

and vice versa due to the stress. This leads the electroforming member or the nonconductive section to be damaged. For this reason, it is preferable that the nonconductive section has elasticity.

FIG. 9 illustrates an electroforming process performed in the core material having the nonconductive section. A negative electrode is connected to the core material 6 and a positive electrode is connected to the electroforming tub so that the electroforming process is performed. Then, ionized metals move to the circumference of the core material 6 to form an electroforming metal layer 11. The electroforming metal layer 11 is separated at several intervals by the nonconductive section.

FIG. 10 illustrates the electroforming member formed in the core material having the nonconductive section.

Once the electroforming metal layer is grown to have a certain thickness, a desired electroforming member 12 is completed.

FIG. 11 is an example of the nonconductive section formed at both ends of the electroforming member of FIG.

11. A specific shape may be formed at both ends 13 and 14 of the nonconductive section.

FIG. 12 is an example of the nonconductive section having lower and upper sections. The nonconductive section is divided into an upper section 15 and a lower section 16 around the core material. The upper and lower sections 15 and 16 can be coupled with or detached from each other. A through hole may be formed in the middle portion of the nonconductive section so that the core material may be inserted into the through hole.

FIG. 13 illustrates the nonconductive section formed in the die. A space portion 18 constituting the shape of the nonconductive section is formed in a die 20. A liquid

type nonconductive material is injected into the space portion 18 through an injection hole 17. At this time, a core material 19 is positioned in the die 20. Once the liquid type nonconductive material in the die is hardened, the die is divided into both sides so that the core material having the nonconductive section is taken out.

The electroforming member of the present invention may include a multiple layer of different kinds of metals, which is formed by varying metal in the electroforming tub.

FIG. 14 illustrates a process of manufacturing a cut electroforming member having a stepped form. A number of nonconductive sections 21 are formed in a core material 22 at several intervals. The electroforming process is performed in the core material 22 to form an incipient electroforming metal layer 23. A nonconductive portion is formed on the surface of the electroforming metal layer 23.

An example of the nonconductive portion includes a photoresist 24. An exposing portion and an unexposed portion are formed in the photoresist through a film. The unexposed portion is washed to form a space portion. The electroforming process is formed again in the incipient electroforming metal layer where the space portion is formed. An electroforming metal layer 26 is additionally formed only in the space portion.

A stepped form can be obtained in the electroforming metal layers 23 and 26 through the above processes.

The electroforming member cut by the nonconductive sections 21 can be obtained and its section can be grown in the same sectional shape as that of the nonconductive section.

In addition to the photoresist, an ultraviolet hardener hardened by ultraviolet rays may be used as the nonconductive portion for the stepped form. In other words,

after the ultraviolet hardener is deposited, a desired portion is only hardened by irradiating ultraviolet rays through a film to form a hardening portion and the other portion is washed to form a space portion. Also, a nonconductive shape portion can be formed in the core material or the incipient electroforming metal layer to obtain a stepped form. An example of the nonconductive shape portion includes a tube, especially, a rubber tube, an elastic tube, a heat contraction tube, silicon jet, rubber jet, plastic jet, or other cylindrical shape portion.

FIG. 15 illustrates a process of manufacturing a cut electroforming member having an inclined stepped form.

Even though the stepped form is formed in the same manner as FIG. 14, an inclined plane may be required in the stepped form. To this end, the inclined plane should be formed in the nonconductive shape portion for the stepped form. The nonconductive shape portion 27 having the inclined plane is formed in the core material or the incipient electroforming metal layer or the electroforming metal layer 26. As an example, a compressed tube 27 whose section is cut to obtain an inclined plane is formed on the electroforming metal layer 26 and the electroforming process is performed so that the cut electroforming member 29 having a stepped form with an inclined plane can be obtained. The nonconductive shape portion can have various sectional shapes in addition to a simple inclined plane.

FIG. 16 illustrates a perspective view and a sectional view of the electroforming member of FIG. 15.

Once the core material of the cut electroforming member is removed, a through hole 37 is formed in the electroforming member. The electroforming member provided with different outer diameter portions 31,33 and 35, an inclined plane

portion 34, a rectangular shaped portion 32, and processing portions 30 and 36 recessed at both ends can be obtained. Both ends of the cut electroforming member are processed in the same sectional shape as that of the nonconductive section.