Method of producing a hollow metal member and an electroforming apparatus for performing the method

Abstract

A method of producing a hollow metal member and an apparatus for producing the same wherein a hollow metal member has uniform thickness of the electrodeposited metal material on the core wires, uniform outer diameter and high accuracy of roundness and coaxiality. The method of producing a hollow metal member according to the present invention comprises the steps of: holding a conductive core wire as a material to be electrodeposited and one of an electrodeposit metal material and a metallic mesh basket for accommodating the electrodeposit metal material in a state horizontally opposed from each other; connecting a cathode of a power source to at least both end portions of the core wire; connecting an anode of the power source to at least both end portions of one of the electrodeposit metal material and the metallic mesh wire basket for accommodating the electrodeposit metal material; immersing one of the electrodeposit metal material and the metallic mesh basket and the core wire in an electrolytic cell charged with electrolytic solution; depositing the electrodeposit metal material on a surface of the core wire which is rotated in the electrolytic cell in a state of applying an electric power by means of electroforming to form an electroformed product; and removing the core wire from the electroformed product having a predetermined thickness.

Description

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a method of producing a hollow metal member as narrow tubular metal member through electroforming and an electroforming apparatus for performing the method. In particular, the present invention relates to a technique for producing a ferrule made of metal, which is used for connecting optical fibers or for connecting an optical fiber and an optical device with each other.

[0003] 2. Description of the Invention

[0004] A ferrule, as an important component in the optical communication, has a hollow configuration as shown in FIG. 7 and has a length L of about 10 mm, an outer diameter D of 1.25 to 2.5 mm and an inner diameter d of 0.126 mm corresponding to the standard of the optical fiber of which outer diameter is 0.125 mm.

[0005] Conventionally, a ferrule made from zirconia has been dominantly used, which is complicated in the production process and the ferrule with high dimensional accuracy cannot be efficiently produced. For this reason, in recent years, a ferrule made of metal produced by electroforming has been proposed.

[0006] As an example of the basic technique of a method of producing a pipe-shaped metal member through electroforming, the Japanese laid-open patent publication No. 11-193485 discloses a method of producing a fine-hole tube.

[0007] FIG. 8 shows a schematic view for explaining a conventional electroforming apparatus for producing a hollow metal member as a narrow tubular metal member. An electrolytic cell 1 is filled with an electrolytic solution 2. A metallic mesh basket 4 for accommodating electrodeposit metal material (electrolytic deposition of metal), which is connected to an anode of a power source 3. A plurality of core wires 6 as materials to be electrodeposited is provided in a holder 5. A rotation shaft 7 is fixed to the holder 5. A motor 8 is driven to rotate the rotation shaft 7. A cathode of the power source 3 is electrically connected to each of the core wires via the rotation shaft 7 and the holder 5.

[0008] The metallic mesh basket 4 for accommodating the electrodeposit metal material and core wires 6 are immersed in an electrolytic solution such that the lower end portion of each of metallic mesh basket 4 and the core wires are inserted toward the bottom portion of the electrolytic cell 1. The electroforming is performed by applying electric power from the power source 3 to the metallic mesh basket 4 and each of the core wires while rotating the holder 5.

[0009] In the conventional technique, after the electrodeposit metal material is electrodeposited on the core wires 6 to a predetermined thickness, the core wires 6 are removed from the electroformed product to obtain a metal member having a long through hole with the inner diameter corresponding to the outer diameter of the core wires 6. Then, the metal member is cut into those having a predetermined length to obtain a hollow metal as a ferrule, for example, as shown in FIG. 7.

[0010] However, in the conventional technique, a hollow metal member with high dimensional accuracy cannot be obtained in practice, although the conventional technique may be performed theoretically. In the conventional electroforming, when the core wires are used for producing a hollow metal member, the following problem arises. In the product obtained by electroforming process, the electrodeposited hollow metal member having a desired roundness and coaxiality of the hollow portion with respect to the outer circumference cannot be obtained. Especially, when the layer thickness of the electrodeposited metal material in the electroformed product that the metal material is electrodeposited on the core wires is not uniform, the outer circumference fluctuates. As a result, the electroformed product with desired roundness, thickness and coaxiality cannot be obtained. The problem cannot be easily solved in the subsequent process.

[0011] Especially, high accuracy of roundness, thickness and coaxiality are required for the ferrule. For this reason, it is important to solve the problem of non-uniformity of the thickness of the electrodeposited metal material in view of productivity and yield. Naturally, it is required for each of the core wires when electroforming is simultaneously performed to a plurality of core wires.

[0012] When the electroforming is performed by the electroforming apparatus having the structure as shown in FIG. 8, in an extreme case, electroformed products 9 may be different in appearance in the longitudinal and circumferential directions. The problem is all caused by non-uniform thickness of the electroformed product 9 formed by the electroforming.

[0013] As described above, the problem of non-uniformity in outer diameter of the electroformed product may be depend on the configuration of the metallic mesh basket 4 for accommodating metal material to be electrodeposited, as disclosed in the Japanese laid-open patent publication No. 2001-207286. However, in practice, this solution is not sufficient to solve the problem, since the electroformed products have non-uniform thickness of the electrodeposited metal material as shown in FIG. 9.

SUMMARY OF THE INVENTION

[0014] The present invention has been made in consideration of the problems involved in the conventional technique as described above, and the objects of the present invention are to provide a method of producing a hollow metal member and an apparatus for producing the same wherein a hollow metal member has uniform thickness of the electrodeposited metal material on the core wires, uniform outer diameter and high accuracy of roundness and coaxiality.

[0015] To accomplish the above object, a method of producing a hollow metal member according to the present invention comprises the steps of holding a conductive core wire as a material to be electrodeposited and one of an electrodeposit metal material and a metallic mesh basket for accommodating the electrodeposit metal material in a state horizontally opposed from each other; connecting a cathode of a power source to at least both end portions of the core wire; connecting an anode of the power source to at least both end portions of one of the electrodeposit metal material and the metallic mesh wire basket for accommodating the electrodeposit metal material; immersing one of the electrodeposit metal material and the metallic mesh basket and the core wire in an electrolytic cell charged with electrolytic solution; depositing the electrodeposit metal material on a surface of the core wire which is rotated in the electrolytic cell in a state of applying an electric power by means of electroforming to form an electroformed product; and removing the core wire from the electroformed product having a predetermined thickness.

[0016] With the method of producing the hollow metal member, when electroforming is performed, each of the anode and the cathode of the power source is electrically uniformly connected to the entire portion of the core wire and the metallic mesh basket for accommodating the electrodeposit metal material, so that the electrical atmosphere for electrodepositing of metal to the core wire is uniformly created in the entire portion of the core wire and the metallic mesh basket for accommodating the electrodeposit metal material and a uniform thickness of the metal is electrodeposited on the core wire. As a result, a hollow metal member has a uniform outer diameter and high accuracy of roundness, and therefore, when the core wire is removed, a hollow metal member having a high accuracy of coaxiality is obtained.

[0017] Another method of producing a hollow metal member according to the present invention comprises the steps of: installing a plurality of electrolytic cells; in one of the one electrolytic cells, holding a conductive core wire as a material to be electrodeposited and one of an electrodeposit metal material and a metallic mesh basket for accommodating the electrodeposit metal material in a state horizontally opposed from each other, connecting a cathode of a power source to at least both end portions of the core wire, connecting an anode of the power source to at least both end portions of one of the electrodeposit metal material and the metallic mesh wire basket for accommodating the electrodeposit metal material, immersing one of the electrodeposit metal material and the metallic mesh basket and the core wire in an electrolytic cell charged with electrolytic solution, and depositing the electrodeposit metal material on a surface of the core wire which is rotated in the electrolytic cell in a state of applying an electric power by means of electroforming; repeatedly performing the electroforming in other electrolytic cells one after another until an electroformed product has a predetermined thickness; and removing the core wire from the electroformed product.

[0018] With this method, when electroforming is performed, each of the anode and the cathode of the power source is electrically uniformly connected to the entire portion of the core wire and the metallic mesh basket for accommodating the electrodeposit metal material, so that the electrical atmosphere for electrodepositing of metal material to the core wire is uniformly created in the entire portion of the core wire and the metallic mesh basket for accommodating the electrodeposit metal material and a uniform thickness of the metal is electrodeposited on the core wire, which causes outer diameter to be uniform. Further, electrodeposit metal material to the core wires so as to gradually increase the thickness of the metal material allows the outer configuration of the electrodeposited metal material to become considerably smooth without roughness. As a result, a hollow metal member with higher accuracy of roundness, thickness and coaxiality is obtained.

[0019] In the above method of producing a hollow metal member in electroforming in each of electrolytic cell, at least one of current or voltage applying to at least one of the electrodeposit metal material and the metallic mesh basket for accommodating the electrodeposit metal material can be changed gradually from a low current or a low voltage. In addition to the above, in electroforming in each of electrolytic cell, at least one of current or voltage applying to the core wire may be changed gradually from a low current or a low voltage. With these methods, electroforming conditions in each of the electrolytic cells are controlled, so that various kind of electroforming may be performed in each of the electrolytic cell. As a result, it is possible to provide a hollow metal member in which electrodeposit metal material is formed satisfactorily.

[0020] An electroforming apparatus according to the present invention comprises: an electrolytic cell charged with electrolytic solution; a power source; means for holding a conductive core wire as a material to be electrodeposited and one of an electrodeposit metal material and a metallic mesh basket for accommodating the electrodeposit metal material in a state horizontally opposed from each other; means for connecting a cathode of the power source to at least both end portions of the core wire; means for connecting an anode of the power source to at least both end portions of one of the electrodeposit metal material and the metallic mesh wire basket for accommodating the electrodeposit metal material; means for moving one of the electrodeposit metal material and the metallic mesh basket and the core wire in the electrolytic cell; means for rotating the core wire in the electrolytic cell in a state of applying electric power from the power source to deposit the electrodeposit metal material on a surface of the core wire and form an electroformed product; and means for removing the core wire from the electroformed product having a predetermined thickness. With the electroforming apparatus, the method of producing the follow metal member is performed satisfactorily.

[0021] In the above electroforming apparatus, a plurality of electrolytic cells and means for transporting the core wire to the plurality of electrolytic cells one after another can be mounted; and in each electrolytic cell, a conductive core wire as a material to be electrodeposited and one of an electrodeposit metal material and a metallic mesh basket for accommodating the electrodeposit metal material may be held in a state horizontally opposed from each other, the electrodeposit metal material may be deposited on a surface of the core wire which is rotated in the electrolytic cell in a state of applying an electric power by means of electroforming to gradually increase thickness of the electrodeposit metal material on the surface of the core wire. With this electroforming apparatus, the above method of producing the hollow metal member may be performed satisfactorily.

[0022] It is possible that the above electroforming apparatus further comprises; means for holding a plurality of core wires in a state horizontally opposed to one of the electrodeposit metal material and the metallic mesh basket for accommodating the electrodeposit metal material; and means for moving the core wire holding mean to each of the electrolytic cells. With this construction, a plurality of core wires can simultaneously be electrodeposited, which enhances the productivity of the hollow metal member.

[0023] In the afore-mentioned electroforming apparatuses, current/voltage controlling means may be provided to change a value of at least one of a current and a voltage to be applied to the electrodeposit metal material, the metallic mesh basket for accommodating the electrodeposit metal material or the core wire. With this electroforming apparatus, the method of producing the follow metal member can be performed satisfactorily.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be described in further detail with reference to the accompanying drawings wherein:

[0025] FIG. 1 is a side view including partially sectional view of an electroforming apparatus according to an embodiment of the present invention,

[0026] FIG. 2 is a front view of an electrode connecting member according to the embodiment of the present invention;

[0027] FIG. 3 is a drawing for explaining a plan condition of the construction of a production line in the electroforming apparatus according to the embodiment of the present invention;

[0028] FIG. 4 is a drawing for explaining a front condition of the construction of the production line shown in FIG. 3;

[0029] FIG. 5 is a drawing for explaining a constructional relation between a metallic mesh basket for accommodating the electrodeposit metal material and core wires according to the embodiment of the present invention;

[0030] FIG. 6 is a drawing for explaining a condition where an electrolytic solution is stirred in an electrolytic cell according to the embodiment of the present invention;

[0031] FIG. 7 is a cross-sectional view for explaining the configuration and the size of an ordinary ferrule;

[0032] FIG. 8 shows the construction of a conventional electroforming apparatus used for producing a narrow tubular metal member;

[0033] FIG. 9 shows a perspective view for explaining problems in electroformed products produced in a conventional electroforming apparatus; and

[0034] FIG. 10 is a drawing for explaining problems caused by a conventional electroforming.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

[0035] The present invention will be described in detail with reference to the accompanying drawings.

[0036] The inventor of the present invention has studied the problems of non-uniform thickness in outer diameter of the electrodeposited metal material produced by electroforming (electrolytic deposition) for many years and repeatedly conducted experimental tests and found various factors for causing non-uniform thickness of the electrodeposited metal material on the core wires. Especially, it is found that the method of applying an electric power to a core wire and a metallic mesh basket for accommodating electrodeposit metal material and the condition for electrodeposition of the metal material on the core wires cause non-uniformity in the electrodeposited metal material. The metallic mesh basket for accommodating the electrodeposit metal material may be used as a single electrodeposit metal material. Accordingly, hereinafter, the concept of the metallic mesh basket for accommodating the electrodeposit metal material includes a single electrodeposit metal material.

[0037] When electroforming is performed to core wires 6 in a conventional electroforming apparatus as shown in FIG. 8, a metallic mesh basket 4 for accommodating electrodeposit metal material and the core wires 6 are placed in parallel with each other in the vertical direction with respect to the bottom portion of an electrolytic cell. In this state, electroforming is performed by connecting an anode of a power source to only one end of the metallic mesh basket for accommodating the electrodeposit metal material and connecting a cathode of the power source to only one end of the core wires. As a result, the following problems arises:

[0038] A The metallic mesh basket 4 for accommodating the electrodeposit metal material and the core wires 6 are long, so that a current/voltage (electric field) is not uniformly applied from one end to the other:

[0039] B When the distance between the metallic mesh basket 4 for accommodating the electrodeposit metal material and the core wires 6 is long, the electrodeposite metal material electrically deposited from the metallic mesh basket 4 for accommodating the electrodeposit metal material is moved in non-uniform state as shown by arrows in FIG. 10, which may be influenced by gravity, together with the cause as described in the above A It is also one factor for non-uniform electrodeposion; and

[0040] C. The electroforming is continuously performed in the same electrolytic cell 1 in the state as described above for a long time, so that delicate changes in the electroforming condition may occur, even if various adjustments or controls are made.

[0041] In view of the above-mentioned matters, further consideration has been made and various experimental tests have been repeatedly conducted. As a result, it is found that when the method of producing a hollow metal member in the following electroforming apparatus is adopted, a hollow metal member having a high dimensional accuracy of a hollow metal member having fine hole to sufficiently meet to the requirement for a ferrule can be produced. The electroforming apparatus is constructed as follows:

[0042] A. To at least both ends portions of each of the long sized metallic mesh basket for accommodating the electrodeposit metal material and the long sized core wires, proper electrodes are connected;

[0043] B. The metallic mesh basket for accommodating the electrodeposit metal material and the core wires are placed in a state horizontally opposed from each other in an electrolytic cell; and

[0044] C. The core wires are moved to a plurality of electrolytic cells and in each electrolytic cell, electroforming is performed and the electrodeposit metal material is formed on the core wires so as to be made gradually thicker.

[0045] At least one of the above mentioned matters allows a metallic hollow tubular member with a desirable high accuracy to be obtained.

[0046] FIG. 1 shows a side view including partially sectional view of an electroforming apparatus according to an embodiment of the present invention. In this figure, reference numeral 11 denotes an electrolytic cell filled with an electrolytic solution 12. Reference numeral 13 denotes a power source and 14, a metallic mesh basket in the form of reticular cylinder or square for accommodating an electrodeposit metal material. The metallic mesh basked 14 is connected to an anode of the power source 13 at both ends portions and about the central portion and accommodates an electrodeposit metal material. Reference numeral 15 is core wires to be electrodeposited, which may be made from wire material such as stainless, non-metallic material, resinous material plated with metal by electroless plating, fibrous material. Reference numeral 16 denotes chuck members provided with the core wire 15 having both ends enclosed therein. Reference numeral 17 denote a holder as a support jig which is placed so as to cover the upper portion of the electrolytic cell 11 The holder 17 having suspended portions 17a by which the chuck members are rotatably supported allows a plurality of core wires 15 to be supported. The holder 17 is driven to lower by a moving means, which will be described later, to immerse the core wires 15 in the electrolytic solution 12 in the electrolytic cell 11, and the holder 17 is driven upwardly to take out the core wires 15 from the electrolytic cell 11. Further, the holder 17 is driven to allow a back and forth motion (in a direction vertical to the surface of the paper on which FIG. 1 is illustrated) of the core wires 15 in the electrolytic cell 11 to stir the electrolytic solution 12.

[0047] Further, reference numeral 18 denotes a rotation shaft which is connected to the chuck members 16 to transmit the driving force for rotating the core wires 15 in the circumferential direction. Reference numeral 19 denotes a driving gear fixed to the rotation shaft 18. Reference numeral 20 denotes a worm gear for rotating the driving gear 19, and 21, a motor for driving the worm gear 20 via a belt 22.

[0048] A plurality of cap electrodes 23 is provided at one end portion of the chuck member 16, as shown in the left side in FIG. 1 and at the outer end portion of the rotation shaft 18, as shown in the right side in FIG. 1. As illustrated in FIG. 2, the cap electrodes 23 are provided on an electrode connecting member 24 and electrically connected to cathodes of the power source 13 via a common electrode 25, as will be described later.

[0049] FIG. 3 is a drawing for explaining a plan condition of the construction of a production line in the electroforming apparatus according to the embodiment of the present invention. FIG. 4 is a drawing for explaining a front condition of the construction of the production line shown in FIG. 3. A portion 26 consisting of a plurality of electrolytic cells 11 is provided. At an upper stream of the production line as shown in left side in FIGS. 3 and 4, a first washing portion 27 consisting of a plurality of cells for washing the core wires 15 before electroforming are provided and at an lower stream of the line, a second washing portion 28 consisting of a plurality of cells for washing the core wires 15 after electroforming.

[0050] Further, reference numeral 29 denotes moving means which comprises a means for moving the holder 17 vertically to the portion 26, the first washing portion 27 and the second washing portion 28 to take in or out the core wires in each cells. The moving means 29 further comprises a moving means for moving the holder 17 to each of the cells and a horizontally moving means for allowing a back and forth motion of the holder 17 (right and left motion in FIG. 4) to stir the electrolytic solution 12 in a state which the core wires 15 are immersed. Reference numeral 30 denotes a motion control means for controlling the moving means 29, and 31, a current/voltage control means which comprises a computer, for instance, to variably control at least one of the values of a current or voltage from the power source 13 applied to the metallic mesh basket 14 for accommodating the electrodeposit metal material and the core wires 15 in each of the electrolytic cells. In this case, the variable control may be performed to at least one of the metallic mesh basket 14 and the core wires 15.

[0051] As described above, the holder 17 is movable to each of the cells. For this reason, as shown in FIGS. 1 and 2, the cathode of the power source is electrically connected to the common electrode 25 in the electrode connecting member 24 installing the cap electrode 23, so that the common electrode 25 is connected to a sliding electrode 32 installed at the ends of the holder 17 by an electric wire 33. The sliding electrode 32 is electrically connected to the power source 13 via electrodes 34 each having a spring. As a result, when the holder 17 moves, the electric power can be applied without disconnection of the electrodes 34 from the sliding electrodes 32. Further, the electrodes 34 having springs are served to perform the function to keep strength against chemical tensile stress in electroforming (electrolytic disposition).

[0052] In the construction according to the embodiment of the present invention as described above, the anodes of the power source 13 are electrically connected to at least both ends portions of the metallic mesh basket 14 for accommodating the electrodeposit metal material, (it may be considered that the cathode is electrically connected to those such as a central portion, except for the both ends portions of the core wire 15, if it is permitted mechanically), and the cathodes of the power source 13 are electrically connected to the both ends of the core wires (in the core wires 15, the cathode is electrically connected to those such as a central portion except the both ends portions, if it is possible mechanically), so that the condition of the electric field in the metallic mesh basket 14 for accommodating the electrodeposit metal material and the core wires 15 each having long configuration may be made uniformly from one end to the other. As a result, the electrodeposite condition on the core wires 15 by electroforming is made uniformly in the longitudinal direction, allowing the electroformed product to have an identical outer diameter in the whole length thereof.

[0053] Further, as shown in FIG. 1, the metallic mesh basket 14 for accommodating the electrodeposit metal material and the core wires 15 are placed in parallel with each other and in a state horizontally opposed to in the electrolytic cell 11 and electroforming is performed while rotating the core wires 15, so that the electrodeposit metal material may be uniformly electrodeposited on entire surface of the core wires 15 in the longitudinal direction, as compared with a conventional apparatus of the kind.

[0054] Further, the metallic mesh basket 14 for accommodating the electrodeposit metal material may be placed in a higher position than the core wires 15, in the electrolytic cell 11.

[0055] Further, the roundness of the electroformed products obtained under various conditions are measured and it is found that the relationship between the metallic mesh basket 14 for accommodating the electrodeposit metal material and the core wires 15 is also preferable in the following construction.

[0056] As shown in Fig, 5, in the longitudinal direction of the metallic mesh basket 14 for accommodating the electrodeposit metal material, the metallic basket 14 is preferably constructed such that each diameter d1, of the both end portions and the diameter d2 of the central portion are in the ratios of about 1.3:1 and the metallic mesh basket 14 and the core wires 15 are separated from each other by a spacing distance X of about 55 to 65 mm. Further, in practical electroforming, the spacing distance is measured by using ultrasonic waves to continuously observe the spacing distance X and are controlled so as to be within a predetermined range. As a result, the perfect roundness of the electroformed product can be enhanced.

[0057] Further, as shown in FIGS. 3 and 4, the core wires 15 are orderly moved to a plurality of the electrolytic cells 11 by the moving control means 30 and the value of the current or the voltage to be applied to the metallic mesh basket 14 and the core wires 15 is variably controlled by means of the voltage/current control means 31 to start the elctroforming from the electrolytic cells set at a low current/a low voltage. Then, the electrodeposit metal material is formed on the core wires to be made thicker gradually, so that the electrodeposit metal material is smoothly formed on the outer circumferential portion and has a fine configuration without roughness. As a result, the electrodeposited metal material on the core wires is uniformly made in the longitudinal direction.

[0058] Further, when the current or voltage is variably controlled at a low current/a low voltage having a low current density, it is preferable that the spacing distance X (gap) shown in FIG. 5 is made narrower and the spacing distance X is made longer as the current density becomes higher.

[0059] In the embodiment according to the present invention, as shown in FIG. 6, the core wires 15 is driven to rotate and to move horizontally (right and left reciprocating motion), while moving to another electrolytic cell 11 in a state of being immersed in the electrolytic solution. By this movement of the core wires, the electrolytic solution 12 is stirred, which is important to surround the core wires with fresh electrolytic solution, and to make the electroforming condition excellently. Further, it is important to enhance the uniformity of the electrodeposited metal material together with the current condition which is kept constant in the metallic mesh basket 14 and the core wires 15, as described above.

[0060] Further, reference numeral 35 in FIG. 6 denotes a pipe as a part of a circulating system capable of circulating of the electrolytic solution 12 and changing into a fresh solution. For stirring the electrolytic solution 12, various measures can be taken. For example, the metallic mesh basket 14 for accommodating the electrodeposit metal material may be moved reciprocatively in the electrolytic cells 12.

[0061] As described above, the electroforming is performed in the production line as shown in FIGS. 3 and 4, and the electroformed product having a predetermined thickness is subjected to the washing process. Then, the core wires 15 are extracted or chemically removed from the electroformed product or the core wire portions is subjected to mechanical process so as to have a predetermined diameter. As a result, a metal member with fine hole is obtained.

[0062] Further, with respect to the arrangement of the production line, L-shaped arrangement or U-shaped arrangement in each cells can be considered in addition to linear arrangement as shown in FIG. 3.

[0063] In removing the core wires, since the metal material may be uniformly electrodeposited on the entire surface and length of the core wires 15 and the obtained electroformed product is uniform in outer diameter, the metal member from which the portion corresponding to the core wire 15 is removed is a hollow metal member with high accuracy of roundness, thickness and coaxiality. Further, the electrodeposit metal material is gradually electrodeposited on the core wires to increase the thickness, so that the circumferential configuration is very smooth and fine without roughness. As a result, a hollow metal member with higher accuracy of roundness, thickness and coaxiality can be obtained.

[0064] For this reason, an excellent result can be obtained, which is suitable for the production of a product such as a ferrule for which high accuracy of roundness, thickness and coaxiality are required. For example, the high accuracy of roundness and coaxiality of about ±1˜3 &mgr;m can be obtained.

[0065] Further, in the production line as shown in FIGS. 3 and 4, when the value of the current/voltage to be applied to the metallic mesh basket 14 for accommodating the electrodeposit metal material and core wires 15 is variably controlled by a computer or the like to perform electroforming in each electrolytic cell, the electrolytic condition in each electrolytic cells 11 can be varied. For this, the electrolytic cell 11, which is not used and vacant, is suitably selected to use and electroforming is performed while moving the electrolytic cells from the selected electrolytic one to another, so that a desirable electroformed product can be produced. As a result, the production method according to the present invention is advantageous in production efficiency and production cost, as compared with the conventional method in which electroforming is continuously performed until the electroformed product has predetermined thickness in a single electrolytic cell.

[0066] As described above, with the method of producing a hollow metal member and the electroforming apparatus according to the present invention, the metal material is electrodeposited on the core wires with uniform thickness by electroforming, the outer diameter of the obtained electroformed product is uniform in the entire surface and length, resulting in high accuracy of roundness. For this, the metal member after the core wires are removed is a hollow metal member with high accuracy of thickness and coaxiality. As a result, a method of producing a hollow metal member and an electroforming apparatus, which are suitable for the production of a product such as a ferrule for which high accuracy of roundness, thickness and coaxiality are required, are realized.

Claims

1. A method of producing a hollow metal member comprising the steps of:

holding a conductive core wire as a material to be electrodeposited and one of an electrodeposit metal material and a metallic mesh basket for accommodating the electrodeposit metal material in a state horizontally opposed from each other;

connecting a cathode of a power source to at least both end portions of said core wire;

connecting an anode of the power source to at least both end portions of one of said electrodeposit metal material and said metallic mesh wire basket for accommodating the electrodeposit metal material;

immersing one of said electrodeposit metal material and said metallic mesh basket and said core wire in an electrolytic cell charged with electrolytic solution;

depositing said electrodeposit metal material on a surface of said core wire which is rotated in the electrolytic cell in a state of applying an electric power by means of electroforming to form an electroformed product; and

removing said core wire from said electroformed product having a predetermined thickness.

2. A method of producing a hollow metal member comprising the steps of:

installing a plurality of electrolytic cells;

in one of said one electrolytic cells, holding a conductive core wire as a material to be electrodeposited and one of an electrodeposit metal material and a metallic mesh basket for accommodating the electrodeposit metal material in a state horizontally opposed from each other, connecting a cathode of a power source to at least both end portions of said core wire, connecting an anode of the power source to at least both end portions of one of said electrodeposit metal material and said metallic mesh wire basket for accommodating the electrodeposit metal material, immersing one of said electrodeposit metal material and said metallic mesh basket and said core wire in an electrolytic cell charged with electrolytic solution, and depositing said electrodeposit metal material on a surface of said core wire which is rotated in the electrolytic cell in a state of applying an electric power by means of electroforming;

repeatedly performing said electroforming in other electrolytic cells one after another until an electroformed product has a predetermined thickness; and

removing said core wire from said electroformed product.

3. The method of producing a hollow metal member as claimed in claim 2, wherein in electroforming in each of electrolytic cell, at least one of current or voltage applying to at least one of said electrodeposit metal material and said metallic mesh basket for accommodating the electrodeposit metal material is changed gradually from a low current or a low voltage.

4. The method of producing a hollow metal member as claimed in claim 2, wherein in electroforming in each of electrolytic cell, at least one of current or voltage applying to said core wire is changed gradually from a low current or a low voltage.

5. An electroforming apparatus comprising:

an electrolytic cell charged with electrolytic solution;

a power source;

means for holding a conductive core wire as a material to be electrodeposited and one of an electrodeposit metal material and a metallic mesh basket for accommodating the electrodeposit metal material in a state horizontally opposed from each other;

means for connecting a cathode of the power source to at least both end portions of said core wire;

means for connecting an anode of the power source to at least both end portions of one of said electrodeposit metal material and said metallic mesh wire basket for accommodating the electrodeposit metal material;

means for moving one of said electrodeposit metal material and said metallic mesh basket and said core wire in the electrolytic cell;

means for rotating said core wire in the electrolytic cell in a state of applying electric power from the power source to deposit said electrodeposit metal material on a surface of said core wire and form an electroformed product; and

means for removing said core wire from said electroformed product having a predetermined thickness.

6. The electroforming apparatus as claimed in claim 5, wherein a plurality of electrolytic cells and means for transporting said core wire to the plurality of electrolytic cells one after another are mounted; and in each electrolytic cell, a conductive core wire as a material to be electrodeposited and one of an electrodeposit metal material and a metallic mesh basket for accommodating the electrodeposit metal material are held in a state horizontally opposed from each other, said electrodeposit metal material is deposited on a surface of said core wire which is rotated in the electrolytic cell in a state of applying an electric power by means of electroforming to gradually increase thickness of said electrodeposit metal material on the surface of said core wire.

7. The electroforming apparatus as claimed in claim 6 further comprising;

means for holding a plurality of core wires in a state horizontally opposed to one of said electrodeposit metal material and said metallic mesh basket for accommodating the electrodeposit metal material; and

means for moving said core wire holding mean to each of said electrolytic cells.

8. The electroforming apparatus as claimed in claim 6, wherein current/voltage controlling means is provided to change a value of at least one of a current and a voltage to be applied to said core wire.

9. The electroforming apparatus as claimed in claim 6, wherein current/voltage controlling means is provided to change a value of at least one of a current and a voltage to be applied to one of said electrodeposit metal material and said metallic mesh basket for accommodating the electrodeposit metal material.

10. The electroforming apparatus as claimed in claim 7, wherein current/voltage controlling means is provided to change a value of at least one of a current and a voltage to be applied to one of said electrodeposit metal material and said metallic mesh basket for accommodating the electrodeposit metal material.

11. The electroforming apparatus as claimed in claim 7, wherein current/voltage controlling means is provided to change a value of at least one of a current and a voltage to be applied to said core wire.