JP2001047345A - Fine hole machining method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To establish a fine hole machining method allowing a bore polishing stably with excellent quality and dimensional accuracy through a single machining, achieving automation of the bore finishing work using one finishing machine, and reducing the processing cost to a great extent. SOLUTION: A blank 1 is provided where a minor diameteric portion 3 of a through hole 2 has diameter enlarging from one side to the other in such an arrangement that the hole diameter of the first named end is over 96% of the maximum finished dimension, the diameter difference between the two ends is less than 5 μm, and the hole bend is under 10 μm, and the blank is grasped by a grasping part 5 capable of rotating and reciprocating from the first end, and bore machining is executed by inserting a wire-form machining tool 6 into the through hole from the other end. The bore machining is performed so that one end of the blank, preferably the minor diameteric side, is grasped and rotated and the wire-form machining tool is inserted from the other end, preferably from the major diameteric side, so that relative reciprocation is generated in the axial direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming pores suitable for automatic processing, and more particularly to a method for forming pores suitable for automatic processing of the inner diameter of a blank of a ferrule for an optical connector.

[0002]

2. Description of the Related Art A ferrule or a capillary for an optical connector is a typical example having an elongated through hole and requiring high dimensional accuracy. Referring to the accompanying drawings, FIG. 14 shows a ferrule 10 in which an optical connector has a capillary 11 and a flange 12 which are separate bodies. That is, the ferrule 10
A capillary 11 in which a small-diameter through hole 13 for inserting an optical fiber 17 (or an optical fiber) is formed along the central axis, and the optical fiber core 1 along the central axis.
6 (the outer periphery of the optical fiber is covered with a jacket) and a flange portion 12 in which a large-diameter through hole 14 for insertion is formed. The end of the capillary 11 on which the tapered diameter portion 15 is formed is fixed to the distal end hole 19 of the flange 12 by tight fitting or bonding or the like, and assembled, and the small diameter through hole 13 of the capillary 11 and the large diameter of the flange 12 are assembled. The through holes 14 are connected via tapered diameter portions 15. A pair of optical fibers 1
The connection of 7, 17 is performed by inserting the ferrules 10, 10 into which they have been inserted and joined, from both ends of the sleeve 18, and
This is performed by abutting the end faces of the ferrules 10, 10, whereby the tips are abutted and connected with the axes of the optical fibers 17, 17 aligned. On the other hand, FIG. 15 shows an optical connector ferrule 10a in which the capillary portion 11a and the flange portion 12a of the optical connector are integrated.

[0003] The diameter of the small diameter through hole 13 for inserting an optical fiber varies depending on the type. For example, a capillary (ferrule) called SC type has a diameter of 0.126 mm.
It has pores with a depth of 10 mm. In an optical connector, since it is required that the relative positions of two optical fibers to be connected are accurately matched, high dimensional accuracy is required for the outer diameter and inner diameter of the ferrule or capillary (in particular, the inner diameter near the abutting surface). Is required. 2. Description of the Related Art Conventionally, ferrules or capillaries for optical connectors have been manufactured by subjecting a ceramic blank, such as zirconia, formed by injection molding, extrusion molding, or the like, to inner peripheral polishing, outer peripheral polishing, or the like.

[0004] As a method of polishing the inner diameter of a molding material (blank) having pores to be processed, which is produced by injection molding, extrusion molding or the like, conventionally, a plurality of blanks are fixed with low melting point solder such as wood metal. A method of simultaneously performing wire wrapping (metal set method) and a method of performing wire wrapping one blank at a time are known. For example, for a ferrule blank,
A plurality of blanks are passed through a setting wire, and each blank is fixed to a holder with wood metal while the wires are tensioned. Next, after removing the setting wire and passing through a tapered polishing wire, the blank is rotated together with the holder while supplying an abrasive such as a polishing powder or a diamond slurry of an appropriate particle size, and at the same time, the polishing wire is Are reciprocated in the axial direction, thereby simultaneously processing the pores of a plurality of blanks. After processing, the wood metal is melted, and the blank is removed from the holder and washed. This method has the advantage that a plurality of blanks can be processed at the same time, but has the disadvantage that the processing allowance must be increased because the hole diameters of the blanks vary. In order to solve this problem, there is a method in which a plurality of blanks are not fixed to a holder, a plurality of blanks are passed through a stretched polishing wire and held in a floating state, and the blanks are rotated one by one to perform a lapping process. (Patent No. 2542
982).

[0005]

However, in both the conventional metal setting method and the method of processing blanks one by one as described above, a plurality of blanks must be passed through a wire, and a wire passing / removing operation must be performed after processing. Will be needed. In particular, in the case of the metal setting method, a plurality of blanks are passed through the setting wire, fixed to the holder, then the blank fixing holder is pulled out, and the blank is again passed through the polishing wire.
It requires a lot of wire passing work. Such a wire passing / removing operation is a major factor that hinders automation of pore processing. Further, in the case of the wire wrapping as described above, it is necessary to separately manufacture a polishing wire having a taper, and to replace the used polishing wire member as a whole at the time of replacement. Therefore, there is a problem that the cost of the polishing wire is increased.

The present invention solves the above-mentioned problems associated with the wire wrapping process, and eliminates the need to manually perform the wire passing / removing operation. An object of the present invention is to provide a method of performing processing by inserting a linear processing tool into the pores of one blank, thereby attempting to automate the processing of the pores. As a device that can perform such pore processing,
There is a processing machine as proposed in International Publication WO97 / 26113. However, with a normal blank,
It is necessary to increase the processing allowance due to the surface roughness, bending, and taper of the pores. For example, in the case of a blank for a ferrule, 20 μm or more is required. Since the inside diameter of the pores of the blank is small and the linear processing tool is considerably thin, when performing large processing, several types of linear processing tools must be prepared and processing must be performed stepwise a plurality of times. Therefore, a plurality of processing machines are required for designing as automatic processing, and the problem that the equipment cost becomes considerably high remains.

[0007]

Means for Solving the Problems The present inventors have solved the above-mentioned problems by adjusting the blanks in advance so as to reduce the machining allowance, and have found that the pores are bent,
By combining the blank production with controlled taper degree and the processing technology by inserting a linear processing tool through the pores of the blank, it was found that the inner diameter polishing can be performed in a single processing step, and thus automation can be achieved. Thus, the present invention has been completed. When manufacturing a blank, it is necessary to adjust one or both of the curvature and the degree of taper of the fine holes. A first aspect of the method for processing a pore of the present invention is a method for processing an inner diameter of a through-hole of an article having a through-hole including a large-diameter portion and a small-diameter portion to be processed. Is prepared by preparing an article having a diameter of 10 μm or less, gripping one end of the article, and inserting a linear processing tool into the through hole from the other end to perform inner diameter processing.

[0008] On the other hand, in a second aspect of the pore forming method of the present invention, the small-diameter portion of the through hole has a hole diameter that increases from one end to the other end, and the hole diameter at one end is the maximum finishing dimension. Of 96
% Or more, preferably 75 μm to 250 μm, and a hole diameter difference between the other end and one end of 5 μm or less is prepared, the article is gripped from one end, and a linear processing tool is inserted into the through hole from the other end. In this way, the inner diameter is processed. Further, in the third aspect of the pore forming method of the present invention, the small-diameter portion of the through-hole has a hole diameter that increases from one end to the other end, and the hole diameter at one end is 96 mm, which is the maximum finishing dimension.
% Or more, preferably 75 μm to 250 μm, a hole diameter difference between the other end side and one end side of 5 μm or less, a hole bending of 10 μm or less is prepared, the article is gripped from one end side, and a wire is drawn from the other end side to the through hole. It is characterized in that inner diameter processing is performed by inserting a processing tool in a shape of a circle. In any of the above aspects, it is preferable to rotate the one end side of the article, preferably the small-diameter portion side end while gripping it, and apply a linear processing tool from the other end side, preferably the large-diameter portion side. The inner diameter is processed by inserting and reciprocating relatively in the axial direction.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, according to the pore forming method of the present invention, a blank in which one or both of the curvature and the degree of taper of the pores are adjusted to a dimensional condition capable of reducing a processing margin can be obtained. It is characterized in that it is prepared and combined with a technique of processing by inserting a linear processing tool through a fine hole of a blank held rotatably and reciprocally. By using the blank adjusted to the predetermined dimensional conditions in this way, the inner diameter can be polished with excellent quality and dimensional accuracy in a single processing step, and stepwise inner diameter polishing is not required. Therefore, there is an advantage that automation of the inner diameter finishing can be achieved by one processing machine. As a result, the processing steps can be simplified and the number of labor involved in processing can be reduced. Furthermore, since the linear processing tool can be used by cutting only the worn tip portion and reworking it into a predetermined taper shape, the wire cost can be reduced, and the processing cost is reduced in combination with the above-mentioned labor cost reduction. Can be greatly reduced.

Hereinafter, the pore processing method of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a blank 1 before an inner diameter finishing process used as a capillary 11 of the optical connector ferrule 10 shown in FIG.
It has a through hole 2 composed of a small diameter portion 3 to be processed and a large diameter portion (tapered diameter portion) 4. On the other hand, FIG. 2 shows a blank 1a of another form, which has a through-hole 2a composed of a small-diameter portion 3a and a large-diameter portion 4a to be processed similarly. This blank 1a can be made into a blank as shown in FIG. 1 by cutting the end of the large diameter portion 4a while leaving the tapered diameter portion. In this specification, the term “large-diameter portion” means a portion having a larger diameter than the small-diameter portion, and is a concept including both the tapered-diameter portion shown in FIG. 1 and the large-diameter through-hole portion shown in FIG. is there. Blank 1 and 1a shown in FIGS.
Is microporated according to the present invention. Further, a ferrule integrated with a capillary and a flange shown in FIG. 15 and a blank having a form other than the ferrule (capillary) can be processed according to the present invention.

In general, a blank having pores produced by injection molding, extrusion molding, or the like has various sizes of curved or tapered pores, and the range of the pores varies and is constant. Not. FIG. 3 is a diagram showing a hole X of the through hole 2 generated in the blank 1 shown in FIG. 1 in an enlarged and deformed manner so as to be easily understood. FIG. 4 is a diagram showing a difference in hole diameter (taper difference) of the tapered through hole 2. It is the figure which showed Y by enlarging deformation. The ferrule for an optical connector is a component for connecting an optical fiber, and since the tip surface is processed after bonding the optical fiber to the through hole of the capillary, it is desirable that the bending of the through hole is small. On the other hand, in the case of the method in which the linear processing tool is inserted into the through hole of the blank and relatively rotated and reciprocated to perform the processing, the effect of correcting the hole bending is not so large. The inventor of the present invention has found that, when the blank 1 having a small hole curvature X of a predetermined ratio or less is used, it is possible in a single step to perform internal diameter processing of a quality sufficient for use as a ferrule even with the above processing method. For example, in the case of the SC type ferrule, the finished inner diameter of the capillary small diameter portion is 126 μm, and if the blank bends before processing is 10 μm or less, the outer diameter is deflected (coaxiality: both ends of the through hole are supported. The inner diameter can be machined to a predetermined quality and size without being affected by the deviation of the outer diameter when rotated in the rotating manner or the taper of the inner diameter.

Further, the present inventors have found that when the taper of the through hole 2 of the blank 1 is small, the number of processing passes (the number of stepwise processing steps) of the linear processing tool can be reduced. . For example, in the case of the SC ferrule described above,
The hole diameter (minimum diameter) Z at one end of the through hole 2 of the blank 1 is 1
When a blank having a hole diameter difference Y of 10 μm and the other end side larger than 5 μm was used (see FIG. 4), three machining passes were required until a predetermined dimensional accuracy was satisfied. Was 120 μm or more and the hole diameter difference Y was 5 μm or less, the blank was completed by one processing, and the roundness of the processed hole was stable at 0.5 μm or less. In the case of the SC type ferrule, the maximum diameter of the small diameter portion of the through hole 2 of the blank 1 is 250 μm because there is a usage in which two optical fibers are passed.
m or less. Needless to say, in order to perform the pore polishing with the minimum processing margin, it is preferable to use a blank prepared so as to satisfy both the above-mentioned conditions of the hole bending and the taper degree.

FIG. 5 and FIG. 6 are schematic views for explaining the pore processing method of the present invention. Capillary blank 1
The end of the small-diameter portion 3 is gripped by a gripper (chuck mechanism) 5 of the processing apparatus, and is rotated and reciprocated in the direction of the arrow (FIG. 5). In this state, a linear processing tool (long wire) 6 whose front end portion is tapered and held by a pair of reciprocally rotatable driving rolls 7 as a driving device penetrates from the large diameter portion 4 side. It is inserted into the hole 2 (FIG. 6) and reciprocated in the axial direction as shown by the arrow, and the inner diameter is polished while supplying an appropriate abrasive as in the conventional case. When the tapered tip of the linear processing tool 6 has worn out after finishing the predetermined number of times of processing, the linear processing tool 6 is moved to the processing tool cutting processing section 8 arranged near the processing apparatus, and the worn tip is removed. After being burned and processed into a predetermined shape using a grindstone, it is subjected to the next inner diameter polishing process. The tip of the linear processing tool can be processed by a chemical method such as etching, in addition to mechanical processing.

In the illustrated example, both the blank 1 and the linear processing tool 6 are reciprocated, but either one of them may be reciprocated. As for the direction in which the linear processing tool 6 is inserted into the through hole 2 of the blank 1, it is preferable to insert the linear processing tool 6 from the large-diameter portion 4 side rather than the small-diameter portion 3 side. In particular, in the case of a ferrule (capillary) for an optical connector, since the end surface on the small diameter portion 3 side is a contact surface with a mating ferrule (capillary), the ferrule (capillary) can be inserted from the large diameter portion 4 side so as not to be erroneously damaged. desirable. In some cases, when the large diameter portion 4 is tapered, the large diameter portion 4 may function as an insertion guide for a linear processing tool. As the processing apparatus, the apparatus described in International Publication WO97 / 26113 can be appropriately modified in design and operating conditions can be set and used. Therefore, detailed description thereof will be omitted.

[0015]

EXAMPLES Hereinafter, examples will be described in which the inner diameter of a capillary blank manufactured by injection molding is polished according to the present invention, and the effect of the present invention is specifically confirmed. The blanks used were injection molded products made of zirconia and had the shape shown in FIG. 1, and 50 blanks were used. FIG. 7 shows the distribution of the bending of the through hole of the blank used, FIG. 8 shows the distribution of the hole diameter at the tip, FIG. 9 shows the distribution of the taper value of the through hole, and the deflection value of the outer diameter (work deflection value). Is shown in FIG. The blanks having various hole diameters and taper values in this way are shown in FIG. 11 for the non-circularity distribution and the concentricity distribution in FIG.
FIG. 13 shows the distribution of the average inner diameter value.

Here, the term "non-circularity" means the difference between the major axis (LD) and minor axis (SD) of a hole having a cross-sectional elliptical diameter is the average internal diameter (MD).
Represents the percentage (LD-SD) / MD × 100 divided by, and means the deviation from the roundness. "Concentricity" refers to the center of the outer circle when a circle is created with the minor diameter obtained by measuring the outer diameter of the tip surface, and the inner circle when the circle is created with the minor diameter obtained by measuring the inner diameter. The concentricity is represented by a value twice as large as the center deviation. A processed product having a concentricity of 1.4 or less has a product value, and a preferable concentricity is 1.0 or less. Also,
The “inner diameter average” represents an average diameter when a circle is formed with the shorter diameters of the small diameter portion on the tip side and the large diameter portion side. 7 to 10
As is clear from FIGS. 11 to 13, according to the method of the present invention, a product having sufficient quality and dimensional accuracy as a capillary for an optical connector can be processed at a high yield by a single inner diameter polishing process.

[0017]

As described above, the method for forming a pore according to the present invention provides a method for manufacturing a blank in which one or both of the curvature and the degree of taper of the pores are adjusted to dimensional conditions capable of reducing the machining allowance. Combines with the processing technology of inserting a linear processing tool through the pores of the blank while relatively rotating and reciprocating, so that a single processing step stably provides excellent quality and dimensional accuracy The inner diameter polishing can be performed at a high yield, and stepwise inner diameter polishing is not required, so that there is an advantage that automation of the inner diameter finishing can be achieved by one processing machine. As a result, the processing steps can be simplified and the number of labor involved in processing can be reduced. Furthermore, the linear tool cuts only the worn tip,
Because it can be used by reworking into a predetermined taper shape,
The wire cost can be reduced, and the processing cost can be significantly reduced in combination with the reduction of the labor cost.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a blank to be processed into a capillary of a ferrule for an optical connector.

FIG. 2 is a cross-sectional view showing another embodiment of a blank to be processed into a capillary of an optical connector ferrule.

FIG. 3 is a cross-sectional view of a blank, showing the hole bending X in an enlarged deformation.

FIG. 4 is a cross-sectional view of a blank in which a hole diameter difference Y between tapered through holes is enlarged and deformed.

FIG. 5 is a schematic partial cross-sectional view for explaining a pore processing method of the present invention.

FIG. 6 is a partial cross-sectional view showing a state where a linear processing tool is inserted into a through hole of a blank.

FIG. 7 is a graph showing a distribution of hole bending of a through hole of a blank.

FIG. 8 is a graph showing the distribution of the hole diameter at the leading end of the blank.

FIG. 9 is a graph showing a distribution of taper values of through holes of a blank.

FIG. 10 is a graph showing a distribution of run-out values of the outer diameter of a blank.

FIG. 11 is a graph showing a distribution of non-circularity of a processed product after inner diameter polishing.

FIG. 12 is a graph showing a distribution of concentricity of a processed product after inner diameter polishing.

FIG. 13 is a graph showing the distribution of the average inner diameter of the processed product after the inner diameter polishing.

FIG. 14 is a schematic partial cross-sectional view showing a ferrule for an optical connector in which a capillary and a flange are separate bodies.

FIG. 15 is a schematic partial cross-sectional view showing an optical connector ferrule in which a capillary portion and a flange portion are integrated.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1a Blank 2, 2a Through-hole 3, 3a Small diameter part 4, 4a Large diameter part 5 Gripping part 6 Linear processing tool 7 Drive roll 10, 10a Ferrule 11 Capillary

Claims (5)

[Claims] 1. A method for processing an inner diameter portion of a through-hole of an article having a through-hole including a large-diameter portion and a small-diameter portion to be processed, wherein the small-diameter portion of the through-hole has a curvature of 10 μm or less. A method of forming a pore, comprising preparing, gripping one end of the article, and inserting a linear processing tool into the through hole from the other end side to perform inner diameter processing. 2. A method of processing an inner diameter portion of a through hole of an article having a through hole including a large diameter portion and a small diameter portion to be processed, wherein the small diameter portion of the through hole extends from one end to the other end. The diameter of the hole at one end is 96 mm, which is the maximum finish size.
%, And a hole diameter difference between the other end side and the one end side of 5 μm or less is prepared, the article is gripped from one end side, and a linear processing tool is inserted into the through hole from the other end side to perform inner diameter processing. A pore processing method characterized by performing. 3. A method of processing an inner diameter portion of a through hole of an article having a through hole including a large diameter portion and a small diameter portion to be processed, wherein the small diameter portion of the through hole extends from one end to the other end. The diameter of the hole at one end is 96 mm, which is the maximum finish size.
%, The difference in hole diameter between the other end and the one end is 5 μm or less, and the bending of the hole is 10 μm or less. The article is gripped from one end, and a linear processing tool is inserted into the through hole from the other end. A pore processing method characterized by performing internal diameter processing by performing the above. 4. A hole diameter at one end of a small diameter portion of the through hole is 7
4. The structure according to claim 2, wherein the thickness is 5 to 250 [mu] m.
The method described in. 5. An inner diameter processing is performed by rotating the article while gripping one end thereof, inserting a linear processing tool from the other end thereof, and relatively reciprocating in the axial direction. The method according to any one of claims 1 to 4, wherein