RU2509752C2 - Method of making ceramic tips for fibre-optic connectors - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to the technology of making precision fibre-optic components and specifically to the technology of making tips for fibre-optic connectors. The method of making ceramic tips for fibre-optic connectors involves preparing a mixture of fine zirconium dioxide powder with binder, moulding a workpiece of the tip by pressure moulding using a cylindrical mould with a cylindrical metal insert which forms an inner through hole, removing the workpiece of the tip from the mould, removing the insert, calcining and sintering the workpiece, followed by mechanical treatment of the surface of the workpiece. The workpiece is sintered with the cylindrical metal insert, which forms an inner through hole, in an inert medium, and the cylindrical metal insert, which forms an inner through hole, is removed from the workpiece after sintering by drawing at subzero temperature, wherein the inert is a wire element whose cross-section is identical to that of the optical fibre.

EFFECT: ensuring stable dimensions of the tip and preventing further machining of the inner diameter of the tip to the required size.

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Description

The invention relates to the field of production technology for precision parts of fiber optic components, and in particular to the technology for the production of ferrules for fiber optic connectors.

BACKGROUND

In recent years, fiber optic cables are more and more used in communication technology instead of electrical. In optical communication systems, known methods of interconnecting optical fibers are used, including a detachable connection method based on the use of a fiber optic connector.

When using a fiber optic connector, an important aspect is the simplicity of connecting and disconnecting the connector and its resistance to environmental influences. In addition, to create a fiber-optic communication system with a large bandwidth that provides long-distance communication, it is necessary to minimize the loss in the connection provided by the optical connector, and apply methods to reduce the back reflection in the connection to stabilize the radiation introduced into the optical fiber.

All these properties are possessed by fiber-optic connectors made of a ceramic material based on zirconia (see EP No. 0722104, G02B 6/36 from 1994).

This solution contains a technology for the manufacture of ceramic tips, including the time-consuming refinement of the diameter of the inner hole of the tips to the required size, which reduces productivity.

The closest technical solution to the proposed invention is a method of manufacturing ceramic tips for fiber optic connectors based on zirconium dioxide, comprising preparing a mixture of finely divided zirconia powder and a binder (temporary technological binder), molding the blank of a cylindrical tip by injection molding using an injection mold with a cylindrical metal insert to obtain an inner hole in the workpiece insertion, preliminary firing of the molded preform to remove the binder, followed by final firing at high temperature (sintering) and cooling to obtain a cylindrical fired product with a through hole, preliminary machining of the outer surface of the tip blanks, grinding of the ends (preliminary formation of the length of the parts), processing of the inner a through hole, consisting of the preparation of a special cone-shaped wire with a diamond suspension and fine-tuning the diameter of the inner hole of the workpiece to the size of the diameter of the inner hole of the tip, repeated machining of the outer cylindrical surface of the tip relative to the center of the inner hole to give it an exactly round shape and the subsequent machining operations, which allow to obtain parts of the desired shape and geometric dimensions (US Pat. US No. 5615291, CL B23B from 1997).

The disadvantage of this method is the high complexity of fine-tuning the diameter of the inner hole of the tip with the involvement of qualified personnel.

In view of the aforementioned drawback inherent in the prior art, an object of the present invention is to provide a method for manufacturing ferrules for fiber optic connectors, providing high dimensional stability of ferrules, as well as a high-performance process that does not require the involvement of highly qualified personnel, due to the fact that the diameter of the inner hole is not adjusted. tip to the required size.

SUMMARY OF THE INVENTION

The essence of the invention lies in the fact that in the method of manufacturing ceramic tips for fiber optic connectors, comprising preparing a mixture of finely divided zirconia powder and a binder (temporary technological binder), molding the tip blank by injection molding using a mold with a cylindrical metal insert, forming the inner through hole of the tip, removing the tip blank from the injection mold, removing the cylinders eskoy metal insert, roasting and sintering the blank, machining workpiece surfaces, firing and sintering of the preform is carried out with a cylindrical metal insert forming the interior through hole in any inert a medium that does not contain an oxidizing element - oxygen (nitrogen, hydrogen or in vacuum), and a cylindrical metal insert is removed from the workpiece after sintering, while cooling in liquid nitrogen to a negative temperature, by drawing, while the insert is a transverse wire element a cross-section of which repeats the cross-section of an optical fiber inserted into a tip when assembling a fiber optic connector.

The implementation of the method is illustrated:

- Figure 1, which shows the workpiece of the optical tip (Figure 1g), obtained by the known method, taken by us as a prototype;

- Figure 2, which shows the mold element;

- Figure 3, which shows a diagram of the device for removing the insert.

In figure 1:

a - blank tip with a through hole,

b - tip blank with preliminary machining of the outer surface,

in - blank tip after grinding the ends,

g - blank tip after finishing the inner hole,

d, g - blank tip after repeated machining of the outer surface relative to the center of the inner hole to obtain parts of the desired shape and geometric dimensions.

In figure 3:

1 - cylindrical metal insert;

2 - a clamp;

3 - cover;

4 - tip;

5 - liquid nitrogen;

6 - heat insulator;

7 - the device body.

An example implementation of the method.

We are preparing a thermoplastic mass from a mixture of finely divided nanostructured zirconia powder and a binder (temporary technological binder), consisting of molten paraffin and beeswax.

We form the tip blank by injection molding using an injection mold, the element of which is shown in Figure 2, in the grooves of which a metal cylindrical insert is placed, which is a wire element, the cross section of which repeats the cross section of the optical fiber. In our case, the round wire element had a diameter of 0.127 mm.

Then we carry out preliminary firing of the molded products to remove the temporary technological bundle and the final sintering of the billets, while the operations of sintering the billets with inserts are carried out in a thermal furnace filled with an inert medium (gaseous nitrogen).

After cooling the sintered preforms to room temperature, we remove the inserts from them using the device shown in Figure 3, for which we place the preform with the insert in a vessel with liquid nitrogen and over the edge of the wire element protruding from the device, remove (pull) it from the preform using the effect of the difference in the coefficients of thermal expansion of materials.

After removing the wire element, a short-term cleaning of the resulting inner hole from slags by blowing with compressed air is required, and there is no need for the finishing operation (polishing) of the inner hole of the tip to obtain the diameter of the required size.

Claims (1)

A method of manufacturing ceramic tips for fiber optic connectors (optical fiber connectors), comprising preparing a mixture of finely divided zirconia powder with a binder, molding the tip blank by injection molding using a cylindrical shape with a cylindrical metal insert forming an internal through hole, removing the tip blank from the mold, removing the insert, firing and sintering the workpiece, machining the surface preforms thereof, characterized in that the sintering of the preform is carried out with a cylindrical metal insert forming an internal through hole in an inert medium, and a cylindrical metal insert forming an internal through hole of the preform is removed from the preform after sintering by drawing at a negative temperature, wherein the insert is a wire element whose cross-section repeats the cross-section of an optical fiber.

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