In the present invention, various members such as an ultrafine pipe or bar made by an electroforming process and an ultrafine pipe or bar made by a general process are cut by an etching process.

BACKGROUND ART An ultrafine pipe has been conventionally manufactured by a drawing process that draws a material with gradually reducing its inner and outer diameters.

Instead of such a mechanical drawing process, the present invention employs an electroforming process that forms a new material by moving and growing melted metal ions. In the present invention, the ultrafine pipe has an outer diameter of several microns to several tens of microns or several hundreds of microns and an inner diameter of several microns. The inner diameter of the pipe is limited within the range of dimensions of the outer diameter. In the present invention, the pipe does not necessarily depend on ultrafine diameters. The thick diameter of the pipe comes under the range of the present invention.

Also, the present invention is not limited to an ultrafine pipe made by the electroforming process. That is, a pipe made by a general process will be within the range of the present invention. In addition to the pipe, an

ultrafine bar will be within the range of the present invention. The ultrafine bar includes a processing member processed in a core material by an electroforming process and a bar made by a mechanical process or other methods.

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 is an example of an ultrafine pipe ; FIG. 3 illustrates a covering process of a forming material and a coating process of a conductive material; FIG. 4 illustrates a pipe manufactured by forming an electroforming layer on a conductive metal coating layer; FIG. 5 illustrates a process of removing a core material from an ultrafine pipe; FIG. 6 illustrates the state that a forming material and a conductive material are chemically removed from the pipe; FIG. 7 illustrates a pipe formed of different kinds of metal layers ; FIG. 8 illustrates a method of cutting an ultrafine pipe by an electroforming process; FIG. 9 illustrates various cutting lines by forming an unexposed portion of FIG. 8 in various methods; FIG. 10 illustrates a process of forming edges of an ultrafine pipe cut by an etching process;

FIG. 11 illustrates a pipe having a curved through hole by using a curved core material; and FIG. 12 illustrates a method of cutting a manufactured ultrafine pipe.

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL PROBLEMS The present invention is directed to a method of cutting an ultrafine pipe or bar and an ultrafine pipe or bar cut by it, in which the ultrafine pipe or bar is cut at an exact length by remarkably reducing their processing steps without undergoing any ultra precise mechanical process. In the present invention, various members such as an ultrafine pipe or bar made by an electroforming process and an ultrafine pipe or bar made by a general process are cut by an etching process.

In other words, a photoresist is deposited on an ultrafine pipe or bar to form an exposing portion. The ultrafine pipe or bar is then cut by an etching process.

The method of cutting the ultrafine member by the etching process has advantages in that mass production of the ultrafine member is possible at precise and exact dimensions and at the same time the ultrafine member can be cut at a uniform size.

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. In the conventional method of processing an ultrafine pipe, the ultrafine pipe having a through hole is cut at a uniform length and both ends of the cut ultrafine pipe are processed by later process steps. However, in the present invention, the ultrafine

pipe is manufactured at a uniform length by photoresist and etching processes without any mechanical process. In this case, it is possible to remarkably reduce later process steps and processing cost and to improve productivity. It is difficult to mechanically process the ultrafine pipe. The present invention is characterized in that the ultrafine pipe or bar made by the electroforming process can exactly be cut at a uniform length by photoresist and exposing processes and an etching processes without any mechanical process.

TECHNIAL SOLUTIONS Accordingly, the present invention is directed to a method of cutting an ultrafine pipe or bar and an ultrafine pipe or bar cut 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 cutting an ultrafine pipe or bar and an ultrafine pipe or bar cut by it, in which a photoresist is deposited on the circumference of the ultrafine pipe or bar, an exposing portion is formed in the photoresist, and the ultrafine pipe or bar is cut at an exact length by an etching process.

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, a method of cutting an ultrafine pipe includes the steps of covering a core material passing through a die with a forming material existing at a melted state or a partially melted state in the die, thinly coating the forming material with a conductive material after it is hardened, forming an electroforming layer by connecting a negative electrode to the conductive coating portion and performing an electroforming process in an electroforming tub, thinly depositing a photoresist on the circumference of the electroforming layer to form a photoresist layer and forming an exposing portion and an unexposed portion at a desired shape through a film, etching the unexposed portion by an etching process after washing it, removing the core material in the pipe by a drawing process, and washing the inside of the pipe.

APPLICABLE ADVANTAGES The present invention is directed to a method of efficiently cutting a processing member on an ultrafine pipe or bar and an ultrafine pipe or bar cut by it. The ultrafine pipe or bar having uniform and excellent processing illumination can be obtained by the electroforming process. Also, in the electroforming process, inner and outer diameters of the pipe can exactly be controlled. The conventional ultrafine pipe manufactured by the mechanical process does not have excellent surface illumination. In the present invention, the surface illumination with precision of several microns can be obtained by the electroforming process. A multiple layer can be formed of a material required for the ultrafine pipe or bar cut by the embodiment of the present

invention by layering different kinds of metals and electroforming them. The ultrafine pipe or bar having an outer diameter of several microns or several tens of microns can efficiently be manufactured by the electroforming process.

In the present invention, the ultrafine pipe or bar can uniformly be cut at several intervals, the later process is easy, and the processing cost can remarkably be reduced.

While the present invention has been described and illustrated herein with reference to the preferred embodiments thereof, it will be apparent to those skilled in the art that various modifications and variations can be made therein without departing from the spirit and scope of the invention. Thus, it is intended that the present invention covers the modifications and variations of this invention that come within the scope of the appended claims and their equivalents.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a method of cutting an ultrafine pipe or bar shaped member. The ultrafine pipe or bar includes two types. The one is processed by an electroforming process, and the other one is processed by a general process. The two types of the ultrafine pipe or bar are all cut by an etching process.

In one embodiment of the present invention, a method of cutting an ultrafine pipe includes the steps of covering a core material passing through a die with a forming material existing at a melted state or a partially melted state in the die, thinly coating the forming material with a conductive material after it is hardened, forming an electroforming layer by connecting a negative

electrode to the conductive coating portion and performing an electroforming process in an electroforming tub, thinly depositing a photoresist on the circumference of the electroforming layer to form a photoresist layer and forming an exposing portion and an unexposed portion at a desired shape through a film, etching the unexposed portion by an etching process after washing it, removing the core material in the pipe by a drawing process, and washing the inside of the pipe. 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. Further, in the present invention, the cut pipe is filled with a filling material and is etched to process its edges.

The ultrafine pipe made by the electroforming process of the present invention can reduce processing error in the range of several microns or less and has excellent surface illumination. Also, since a pipe of different kinds of metals can be manufactured, the intensity and conductivity of current can preferably be obtained. The unexposed portion is separated at several intervals in a longitudinal direction of the electroforming member. Also,

the unexposed portion may include a cutting line in a longitudinal direction of the electroforming member. The cutting line may be formed in a screw shape. Both ends of the ultrafine bar cut by the etching process may be processed again by the etching process or a mechanical process such as polishing. The cut ultrafine pipe of the present invention may be used as a ferrule that is a connecting member of an optical cable. In this case, the ferrule has an inner diameter of 125 microns. The cut ultrafine pipe may also be used as a sleeve that is a connecting member of ferrule. The cut ultrafine pipe may further be used as a semiconductor probe provided with a spring. In the present invention, the core material is of metal or plastic. Preferably, stainless having strong tension is used as the core material.

In another embodiment of the present invention, a method of cutting an ultrafine pipe includes the steps of filling a filling material in an inner diameter portion of the pipe, thinly depositing a photoresist on its outer diameter portion to form a photoresist layer, forming an exposing portion in the photoresist layer at a desired shape using a film, washing an unexposed portion of the photoresist layer, etching the unexposed portion, cutting the pipe by an etching process, and removing the filling material in the pipe.

In other embodiment of the present invention, a method of cutting an ultrafine bar includes the steps of depositing a photoresist on a bar shaped electroforming member, forming an exposing portion and unexposed portion by irradiating light into the photoresist at a desired shape using a film, etching the unexposed portion, and cutting the ultrafine bar. The bar shaped electroforming member may be grown on an ultrafine core material by an

electroforming process.

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 to FIG. 7 illustrate a method for manufacturing an ultrafine pipe by an electroforming process. 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. The 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 is an example of an ultrafine pipe. An ultrafine pipe 600 has an outer diameter of several microns to several hundreds of microns. A slider 500 is formed inside the ultrafine pipe and performs sliding movement. It is important that the ultrafine pipe has an inner diameter having processing precision. A conductive metal coating layer having excellent conductivity is required in the inner diameter as the case may be. The conductive metal coating layer may be used to check current characteristic value.

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 used to manufacture the ultrafine pipe of the present invention 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 covered with a melted or partially melted forming material 2, so that any effect of the scratches and the incomplete cylindrical degree on the inner diameter of the ultrafine pipe is minimized. That is, a die 3 is supplied with the forming material 2, and the core material 1 is drawn 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 electroformed pipe and the core material is engaged with the scratches of the pipe. 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 ultrafine pipe is formed by the electroforming process. Since the core material is covered with the forming material of the present invention, the core material is separated from the inner diameter of the electroformed ultrafine pipe. 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 ultrafine pipe. The core material is removed by a drawing process to obtain the ultrafine pipe 5 having a through hole inside the pipe 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 electroformed pipe. Also, there is limitation in improving precision because the scratches of the core material are reflected inside the pipe 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 ultrafine 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 ultrafine pipe. In the present invention, fluidity is given to the forming material 2 by heating the ultrafine pipe having the core material therein so that the core material is easily removed from the pipe. 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 pipe 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 pipe.

If the core material is removed, the forming material 2 remaining in the pipe 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 pipe 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 pipe. 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 ultrafine pipe 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 pipe 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 a pipe formed of different kinds of metal layers. In the present invention, the pipe has various sections different from a section of the core material using the forming material and the die. That is, the pipe 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 illustrates a method of cutting an ultrafine

pipe by an electroforming process. A photoresist is thinly deposited on the electroforming layer 5 formed by the electroforming process to form a photoresist layer. An exposing portion 6 is formed in a desired shape using a film. An unexposed portion is washed and corroded by an etching process to form a cutting portion 7.

FIG. 9 illustrates various cutting lines by forming the unexposed portion of FIG. 8 in various methods. A cutting line may be formed in a longitudinal direction.

The cutting line may be formed with a screw shape in a longitudinal direction. The pipe having a small diameter can be obtained as the case may be.

FIG. 10 illustrates a process of forming edges of the ultrafine pipe cut by the etching process. A filling material 7 is filled in the cut ultrafine pipe 5 having the exposing portion 6. The ultrafine pipe 5 is then digested in an etching solution to undergo chemical corrosion. In this case, a sharp protrusion 8 at both ends of the pipe is etched. Afterwards, the filling material is removed, so that the ultrafine pipe is completed. At this time, the filling material is positioned at the middle portion of the pipe at a length shorter than that of the pipe. Both ends of the cut pipe can mechanically be processed by a polishing process. The protrusion may be processed by performing an electrolytic polishing process in the pipe in a state that the filling material is filled therein.

FIG. 11 illustrates a pipe having a curved through hole by using a curved core material. Since the pipe formed by the electroforming process is grown in the same shape as that of the core material, the core material can be formed in a curved shape in order to form the pipe having a curved inner portion 9.

FIG. 12 illustrates a method of cutting a manufactured ultrafine pipe. A filling material 11 is filled in an ultrafine pipe 10 and a photoresist 12 is deposited on the circumference of the ultrafine pipe 10.

An exposing portion 13 and an unexposed portion 14 are formed by irradiating light into the photoresist through a film. At this time, the unexposed portion is separated at several intervals in a longitudinal direction of the ultrafine pipe. Also, the unexposed portion may include a cutting line of the bar shaped electroforming member. The cutting line may be formed in a longitudinal direction of the ultrafine pipe. Alternatively, the cutting line may be formed in a screw shape. The photoresist of the unexposed portion 14 is removed and etched to form an etching portion 15, thereby cutting the ultrafine pipe. Thus, the longer ultrafine pipe is cut to be manufactured as a short ultrafine pipe 16.

The present invention is not limited to the pipe. An ultrafine bar filled with a filling material will be within the range of the present invention. In other words, a photoresist is deposited on an ultrafine bar filled with a filling material. An exposing portion and an unexposed portion are formed by irradiating light into the photoresist through a film. At this time, the unexposed portion is separated at several intervals in a longitudinal direction of the ultrafine bar. The ultrafine bar is then cut by the etching process. In the present invention, the ultrafine bar means that it has an outer diameter of several microns or several tens of microns, and several hundreds of microns as the case may be. It is difficult to mechanically process such an ultrafine bar.

However, it is possible to easily manufacture an ultrafine bar by performing an electroforming process on the

circumference of an ultrafine core material. Also, if the ultrafine bar is manufactured by the electroforming process, a multiple layer of different kinds of metals can be formed by varying metal in an electroforming tub. Both ends of the ultrafine bar cut by the etching process may be processed more elaborately by a mechanical process such as polishing or cutting process.