US20230003952A1

US20230003952A1 - Integrated optical assembly structure with isolator, and processing method therefor

Info

Publication number: US20230003952A1
Application number: US17/778,416
Authority: US
Inventors: Jun Xu
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-02-28
Filing date: 2019-04-16
Publication date: 2023-01-05
Also published as: CN109932779B; WO2020173042A1; US20210223580A1; WO2020172964A1; CN109932779A; CN110308520A; US11531219B2

Abstract

Disclosed are an integrated optical assembly structure with an isolator and a processing method therefor. The structure comprises a front metal cover, a ceramic sleeve, a pressing block, a ceramic plug core and an isolator chip, wherein the ceramic sleeve is disposed inside the front metal cover; one end of the ceramic plug core is disposed inside the ceramic sleeve and the other end thereof is fixed in the pressing block; the pressing block has a plug core positioning hole and a chip accommodating hole; the chip accommodating hole has at least two positioning corners; and the isolator chip having magnetism itself is installed in the chip accommodating hole and is positioned and fixed via the positioning corners.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of optical communication, and more particularly to an integrated optical assembly structure with an isolator, and a processing method therefor.

2. Description of the Prior Art

In recent years, with the increasing speed of data transmission, the traditional telecommunication is unable to meet the transmission needs in various fields. Optical communication technology makes up for the shortcomings of the traditional telecommunication technology, such as short transmission distance, large energy consumption, and slow transmission speed, so it is widely used in various data transmission. In an optical communication module, when light from a light source, such as a laser, passes through various optical components or optical fibers (or comes out from optical components or optical fibers), part of the light will be reflected or scattered at the end or inside of the various optical components or optical fibers. When the reflected or refracted light returns through the original path, it will interfere with the optical signal and affect the signal quality and stability of the optical communication. Therefore, the isolator in an optical module becomes an indispensable part of optical communication.
As shown in FIG. 1 , a conventional optical assembly comprises a front metal cover 1, a ceramic sleeve 2, a first pressing block 3, a second pressing block 4, a ceramic plug core 5, an outer ring 6, and an isolator chip 7. The isolator 7 is a polarization-dependent free space isolator (FSI), and its structure is shown in FIG. 2 . The isolator 7 is composed of a magnetic ring 71 and an isolator chip 72 installed in the magnetic ring 71. The isolator chip 72 is composed of a Faraday rotator 722, a polarizer 721 disposed on one side of the Faraday rotator 722 where light is incident, and an analyzer 723 disposed on the other side of the Faraday rotator 722. When the Faraday rotator 722 is located in the magnetic field, the vibration plane of the incident light may be rotated by 45°. Both the polarizer 721 and the analyzer 723 are polarizers to filter light outside the target direction, so as to unify the directions of the optical signals incident into the optical assembly to avoid interference. However, the installation of the magnetic ring 71 of the conventional optical assembly needs to cooperate with the second pressing block 4 through the outer ring 6. The installation of the magnetic ring 71, the cooperation between the isolator chip 72 and the magnetic ring 71, and the installation between the second pressing block 4 and the outer ring 6 may cause errors. In order to ensure full coverage of the optical path by the isolator chip 72, its area needs to be large enough to cover these installation errors. Therefore, the side length of the isolator chip 72 needs to be about 0.5 mm. (Due to the cutting process, the Faraday rotator is generally a square sheet). The Faraday rotator and polarizer are very expensive. How to reduce the area of the isolator chip to decrease the manufacturing cost of the optical assembly has become an extremely important issue.
In general, the mounting hole of the magnetic ring 71 for mounting the isolator chip 72 is a round hole, and the isolator chip 72 is cut to have a square shape. During the installation of the magnetic ring 71 and the isolator chip 72, in order to keep the installation angle of the isolator chip 72, several corrections are required, which reduces the assembly efficiency. The circular hole of the magnetic ring 71 may cause the isolator chip 72 to rotate, which increases the assembly difficulty and increases the production cost of the optical assembly greatly.
In order to further reduce the material usage of the optical assembly and reduce the production cost of the optical assembly, the inventor of the present invention has devoted himself based on his many years of practical experiences to solve these problems.

SUMMARY OF THE INVENTION

One of the technical problems to be solved by the present invention is to provide a manufacturing apparatus for delaminating a bamboo into fiber.

(1) Technical Problem to be Solved

The primary object of the present invention is to provide an integrated optical assembly structure with an isolator and a processing method therefor, so as to improve the installation accuracy of the isolator chip and reduce the area of the isolator chip to decrease the production cost of the optical assembly. Another object of the present invention is to provide a simple and efficient processing method for machining a pressing block. For realizing the above-mentioned objects, the present invention adopts the following technical solutions.

(2) Technical Solutions

An integrated optical assembly structure with an isolator comprises a front metal cover, a ceramic sleeve, a pressing block, a ceramic plug core, and an isolator chip. The ceramic sleeve is disposed inside the front metal cover and fixed by the pressing block. One end of the ceramic plug core is disposed inside the ceramic sleeve, and another end of the ceramic plug core is fixed in the pressing block. A plug core positioning hole is defined in one end of the pressing block, located adjacent to the front metal cover, for positioning the ceramic plug core. A chip accommodating hole is defined in another end of the pressing block. The plug core positioning hole communicates with the chip accommodating hole. The chip accommodating hole has at least two positioning corners. The isolator chip is composed of a polarizer, a magnetic Faraday rotator and an analyzer. The isolator chip is installed in the chip accommodating hole and positioned by the positioning corners.
The pressing block includes a first pressing block and a second pressing block. An electrical clearance is defined between the first pressing block and the second pressing block. The first pressing block is fixedly connected to the front metal cover. The plug core positioning hole and the chip accommodating hole are defined in the second pressing block.
Preferably, the positioning corners are each at a right angle.
Furthermore, at least two of the positioning corners are arranged diagonally.
Furthermore, the number of the positioning corners of the chip accommodating hole is four, and the positioning corners are arranged at four corners of the chip accommodating hole.
Furthermore, the chip accommodating hole has a square shape.
Furthermore, the four positioning corners the chip accommodating hole are connected through a circular arc surface.
A processing method for an integrated optical assembly structure with an isolator comprises the following steps of:
step 1, material preparation: selecting and putting a Φ5.5 round bar material into a dual spindle CNC bar feeder, and cutting ends of the material;
step 2, drilling of first center hole: adjusting the rotation speed of a spindle of the dual spindle CNC bar feeder to 2500 r/min-3500 r/min, ensuring the concentricity of a drill head with the spindle, and positioning a center hole by the Z-axis movement of a 3.0 central drill towards the dual spindle CNC bar feeder, wherein the feed rate of the drill head is 0.02-0.03 mm/round;
step 3, drilling of round hole: switching to a Φ0.35 drill head, ensuring the concentricity of the drill head with the spindle, adjusting the rotation speed of the spindle to 4500 r/min-5500 r/min, performing a drilling operation by the Z-axis movement of the drill head towards the dual spindle CNC bar feeder, wherein the feed rate is 0.01-0.02 mm/round, and the drilling depth is 3.0 mm:
step 4, formation of chip accommodating hole: switching to a Φ0.35 broach, ensuring the concentricity of the broach with the spindle, adjusting the rotation speed of the spindle to 300-800 r/min, forming a square hole by the Z-axis movement of the broach towards the dual spindle CNC bar feeder, wherein the feed rate of the broach is 0.005-0.01 mm/round, and the processing depth is 1.5 mm;
step 5, rough turning: switching to a rough turning tool, adjusting the rotation speed of the spindle to 2000-2500 r/min, and performing a rough turning by the X-axis movement of the rough turning tool towards the dual spindle CNC bar feeder, wherein the feed rate is 0.02-0.03 mm/round, and the reserved space is 0.1-0.2 mm;
step 6, fine turning: switching to a fine turning tool, adjusting the rotation speed of the spindle to 3000-3500 r/min, performing a fine turning by the X-axis movement of the fine turning tool towards the dual spindle CNC bar feeder, wherein the feed rate is 0.01-0.02 mm/round;
step 7, cut-off switching to a cut-off knife, adjusting the rotation speed of the spindle to 2000-2500 r/min, performing a cut-off operation by the X-axis movement of the knife towards the dual spindle CNC bar feeder, wherein the feed rate is 0.01-0.02 mm/round, the reserved cut-off length is 0.1 mm, and it is necessary to clamp an outer periphery of a workpiece stage by a sub-spindle while cutting;
step 8, polishing of cut surface: adjusting the rotation speed of the sub-spindle to 2500-3000 r/min, wherein the feed rate of a cutter is 0.01-0.02 mm/round, and then polishing the cut surface;
step 9, drilling of second center hole: adjusting the rotation speed of the sub-spindle to approximately 2500 r/min-3500 r/min, ensuring the concentricity of the drill head with the sub-spindle of the dual spindle CNC bar feeder, and positioning a center hole by the Z-axis movement of the 3.0 central drill towards the dual spindle CNC bar feeder, wherein the feed rate of the drill head is 0.02-0.03 mm/round;
step 10, drilling of plug core positioning hole: switching to a Φ1.2 drill, ensuring the concentricity of the drill head with the sub-spindle, adjusting the rotation speed of the sub-spindle to 2500 r/min-3500 r/min, and performing a drilling operation by the Z-axis movement of the drill head towards the dual spindle CNC bar feeder, wherein the feed rate is 0.01-0.02 mm/round, and the drilling depth is 0.7 mm; and
step 11, boring: switching to a Φ1.24 boring tool, adjusting the rotation speed of the sub-spindle to 2500 r/min-3500 r/min, and performing a boring operation by the Z-axis movement of the drill head towards the dual spindle CNC bar feeder, wherein the feed rate is 0.01-0.02 mm/round, and the boring depth is 0.7 mm.

(3) Beneficial Effect

Compared with the prior art, the present invention has obvious advantages and beneficial effects. Specifically, the present invention utilizes the same pressing block to simultaneously press the ceramic plug core and accommodate the isolator chip, without the outer ring, such that two-step assembly is changed to one-step assembly for installing the isolator chip, thereby improving the assembly accuracy, reducing the area of the isolator chip while ensuring full coverage of an optical path, and reducing the costs of materials greatly. Besides, in the invention, the chip accommodating hole for installing the isolator chip in the pressing block has the positioning corners, so that the positioning of the isolator chip is more accurate when the isolator chip is installed. There is no need to perform complex correction for the isolator chip, which avoids rotation of the isolator chip later on, reduces the assembly difficulty of the isolator chip greatly, reduces the assembly cost, and improves the production efficiency. The invention further provides a processing method for machining the pressing block, with low cost and simple operation, so that the production of the pressing block is more efficient.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view of a conventional optical assembly;

FIG. 2 is a cross-sectional view of the isolator 7 of the conventional optical assembly;

FIG. 3 is a cross-sectional view of the optical assembly structure of the present invention;

FIG. 4 is a schematic view of the isolator chip 50 of the present invention;

FIG. 5 is a cross-sectional view of the second pressing block 32;

FIG. 6 is a schematic view showing the installation of the isolator chip 50 according to a first embodiment; and

FIG. 7 is a schematic view showing the installation of the isolator chip 50 according to a second embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention are described in detail. The exemplary embodiments are shown in the drawings, wherein the same or similar reference numerals indicate the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention, but should not be construed as limiting the present invention.
Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings.
Referring to FIGS. 3 to 7 , an integrated optical assembly structure with an isolator comprises a front metal cover 10, a ceramic sleeve 20, a pressing block 30, a ceramic plug core 40, and an isolator chip 50.
The ceramic sleeve 20 is disposed inside the front metal cover 10 and fixed by the pressing block 30. One end of the ceramic plug core 40 is disposed inside the ceramic sleeve 20, and the other end of the ceramic plug core 40 is fixed in the pressing block 30. A plug core positioning hole 322 is defined in one end of the pressing block 30, located adjacent to the front metal cover 10, for positioning the ceramic plug core 40. A chip accommodating hole 321 is defined in the other end of the pressing block 30. The plug core positioning hole 322 communicates with the chip accommodating hole 321. The isolator chip 50 is composed of a polarizer 51, a magnetic Faraday rotator 52 and an analyzer 53. The isolator chip 50 has magnetism itself. In general, the isolator chip 50 is cut to be in a square shape. Therefore, in order to position the isolator chip 50 precisely when it is installed, to ensure that its installation angle is within the expected range and to prevent the isolator chip 50 from being rotated and offset during and after installation to cause an installation error, the chip accommodating hole 321 has at least two positioning corners 321 a for positioning at least two corners of the isolator chip 50, thereby reducing assembly difficulty and improving assembly accuracy.
In a preferred embodiment, the pressing block 30 includes a first pressing block 31 and a second pressing block 32. An electrical clearance is defined between the first pressing block 31 and the second pressing block 32. The first pressing block 31 is fixedly connected to the front metal cover 10. The plug core positioning hole 322 and the chip accommodating hole 321 are defined in the second pressing block 32.
In order to fit the square isolator chip 50 better, the positioning corners 321 a are each at a right angle. Further, in order to prevent the isolator chip 50 from being rotated and offset in the installation process, at least two of the positioning corners 321 a are arranged diagonally.
In order to facilitate processing and to position the isolator chip 50, the number of the positioning corners 321 a of the chip accommodating hole 321 is four, and the positioning corners 321 a are arranged at four corners of the chip accommodating hole 321. In this regard, the present invention provides two embodiments to illustrate the shape of the chip accommodating hole 321. However, the specific shape of the chip accommodating hole 321 is not limited to the embodiments provided by the present invention. They are just preferred embodiments. Therefore, in actual production, the chip accommodating hole 321 may be in any shape on the basis of having at least two positioning corners 321 a. That is, the connection surface of the positioning corners may be a single surface, multiple surfaces, a circular arc surface, or a multi-curved surface.

First Embodiment

As shown in FIG. 6 , the chip accommodating hole 321 is disposed below the chip positioning hole 322, having a square shape. The four corners of the square are defined as the positioning corners 321 a. The size of the chip accommodating hole 321 is slightly greater than that of the isolator chip 50, so that the installation angle of the isolator chip 50 is offset within ±8°.
Error discussion in the first embodiment: comprehensive processing technology and cost. The side length of the chip accommodating hole 321 is 0.35 mm±0.02 mm Assuming that the chip accommodating hole 321 is offset to one side by 0.02 mm under the condition of the limit error, 0.02 mm is the one-sided error when the isolator chip 50 is installed because the invention doesn't have the outer ring 6 and the magnetic ring 71 and uses the same pressing block 30 to simultaneously press the ceramic plug core 40 and accommodate the isolator chip 50 when compared with the prior art.
Error analysis of the prior art: The coaxiality error requirement of the outer ring 6 installed in the second pressing block 4 of the conventional optical assembly is ⊚0.06 mm. The coaxiality error requirement between the second pressing block 4 and the ceramic plug core 5 is ⊚0.02 mm. If the error of installing the isolator chip 72 in the magnetic ring 71 and the magnetic ring 71 in the outer ring 6 is added, the installation error of the isolator chip 72 may be 0.08 mm on one side.
Comparison of results: The error of the integrated optical assembly structure provided by the present invention is greatly reduced compared with the error of the conventional optical assembly at the laser incident end, so that the offset distance between the center of the isolator and the optical path is reduced, and the side length of the required isolator is reduced to 0.3 mm. Compared with the prior art, the area of the isolator chip is reduced greatly, which reduces the manufacturing cost of the isolator and the assembly difficulty of the optical assembly greatly.

Second Embodiment

As shown in FIG. 7 , the four positioning corners 321 a of the chip accommodating hole 321 are connected through a circular arc surface, that is, the four positioning corners 321 a are formed on the basis of a circular hole. The length of the straight side of the positioning corner 321 a needs to ensure that the isolator chip 50 is still located among the four positioning corners 321 a after being rotated by 8°, without touching the circular arc surface. This structure is simple in processing and is easy in positioning, and can reduce the processing difficulty and processing cost of the chip accommodating hole 321 while ensuring that the installation angle of the isolator chip 50 is offset within ±8°, further improving production efficiency and reducing the production cost of the optical assembly.
Since the pressing block of the present invention is extremely small in size, it is difficult to form the chip accommodating hole 321 and the plug core positioning hole 322 in the pressing block to meet the precision requirements. Besides, the output of the optical assembly is usually very large. The production time of a single part determines the production capacity of the optical assembly to a great degree. Therefore, the pressing block needs to be machined efficiently.
For this reason, the present invention further provides a processing method of an integrated optical assembly structure with an isolator, using a dual spindle CNC lathe, so as to solve the problems of low efficiency and low precision in the conventional processing method. The processing method of the present invention comprises the following steps of:
(Step 1) material preparation: selecting and putting a Φ5.5 round bar material into a dual spindle CNC bar feeder, and cutting ends of the material;
(Step 2) drilling of first center hole: adjusting the rotation speed of a spindle of the dual spindle CNC bar feeder to 2500 r/min-3500 r/min, ensuring the concentricity of a drill head with the spindle, and positioning a center hole by the Z-axis movement of a 3.0 central drill towards the dual spindle CNC bar feeder, wherein the feed rate of the drill head is 0.02-0.03 mm/round;
(Step 3) drilling of round hole: switching to a Φ0.35 drill head, ensuring the concentricity of the drill head with the spindle, adjusting the rotation speed of the spindle to 4500 r/min-5500 r/min, performing a drilling operation by the Z-axis movement of the drill head towards the dual spindle CNC bar feeder, wherein the feed rate is 0.01-0.02 mm/round, and the drilling depth is 3.0 mm:
(Step 4) formation of chip accommodating hole: switching to a Φ0.35 broach, ensuring the concentricity of the broach with the spindle, adjusting the rotation speed of the spindle to 300-800 r/min, forming a square hole by the Z-axis movement of the broach towards the dual spindle CNC bar feeder, wherein the feed rate of the broach is 0.005-0.01 mm/round, and the processing depth is 1.5 mm;
(Step 5) rough turning: switching to a rough turning tool, adjusting the rotation speed of the spindle to 2000-2500 r/min, and performing a rough turning by the X-axis movement of the rough turning tool towards the dual spindle CNC bar feeder, wherein the feed rate is 0.02-0.03 mm/round, and the reserved space is 0.1-0.2 mm;
(Step 6) fine turning: switching to a fine turning tool, adjusting the rotation speed of the spindle to 3000-3500 r/min, performing a fine turning by the X-axis movement of the fine turning tool towards the dual spindle CNC bar feeder, wherein the feed rate is 0.01-0.02 mm/round;
(Step 7) cut-off switching to a cut-off knife, adjusting the rotation speed of the spindle to 2000-2500 r/min, performing a cut-off operation by the X-axis movement of the knife towards the dual spindle CNC bar feeder, wherein the feed rate is 0.01-0.02 mm/round, the reserved cut-off length is 0.1 mm, and it is necessary to clamp an outer periphery of a workpiece stage by a sub-spindle while cutting;
(Step 8) polishing of cut surface: adjusting the rotation speed of the sub-spindle to 2500-3000 r/min, wherein the feed rate of a cutter is 0.01-0.02 mm/round, and then polishing the cut surface;
(Step 9) drilling of second center hole: adjusting the rotation speed of the sub-spindle to approximately 2500 r/min-3500 r/min, ensuring the concentricity of the drill head with the sub-spindle of the dual spindle CNC bar feeder, and positioning a center hole by the Z-axis movement of the 3.0 central drill towards the dual spindle CNC bar feeder, wherein the feed rate of the drill head is 0.02-0.03 mm/round;
(Step 10) drilling of plug core positioning hole: switching to a Φ1.2 drill, ensuring the concentricity of the drill head with the sub-spindle, adjusting the rotation speed of the sub-spindle to 2500 r/min-3500 r/min, and performing a drilling operation by the Z-axis movement of the drill head towards the dual spindle CNC bar feeder, wherein the feed rate is 0.01-0.02 mm/round, and the drilling depth is 0.7 mm; and
(Step 11) boring: switching to a Φ1.24 boring tool, adjusting the rotation speed of the sub-spindle to 2500 r/min-3500 r/min, and performing a boring operation by the Z-axis movement of the drill head towards the dual spindle CNC bar feeder, wherein the feed rate is 0.01-0.02 mm/round, and the boring depth is 0.7 mm.
The feature of the present invention is to use the same pressing block to simultaneously press the ceramic plug core and accommodate the isolator chip, without the outer ring. With the isolator chip having magnetism itself, that two-step assembly is changed to one-step assembly for installing the isolator chip, thereby improving the assembly accuracy, reducing the area of the isolator chip while ensuring full coverage of an optical path, and reducing the costs of materials greatly. Besides, in the invention, the chip accommodating hole for installing the isolator chip in the pressing block has the positioning corners, so that the positioning of the isolator chip is more accurate when the isolator chip is installed, so as to avoid the rotation of the isolator chip later on. There is no need to perform complex correction for the isolator chip. This reduces the assembly difficulty of the isolator chip greatly, reduces the assembly cost, and improves the production efficiency. The invention further provides a processing method of an integrated optical assembly structure with an isolator, using a double-spindle CNC lathe to cooperate with a broach. The entire pressing block is machined by one-time clamping, so the processing efficiency and precision of the optical assembly are improved. It is suitable for large-scale production for the optical assembly.
Although particular embodiments of the present invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the present invention. Accordingly, the present invention is not to be limited except as by the appended claims

Claims

What is claimed is:

1. An integrated optical assembly structure with an isolator, comprising a front metal cover, a ceramic sleeve, a pressing block, a ceramic plug core and an isolator chip, the ceramic sleeve being disposed inside the front metal cover and fixed by the pressing block, one end of the ceramic plug core being disposed inside the ceramic sleeve, another end of the ceramic plug core being fixed in the pressing block, a plug core positioning hole being defined in one end of the pressing block, located adjacent to the front metal cover, for positioning the ceramic plug core, a chip accommodating hole being defined in another end of the pressing block, the plug core positioning hole communicating with the chip accommodating hole, the chip accommodating hole having at least two positioning corners, the isolator chip being composed of a polarizer, a magnetic Faraday rotator and an analyzer, the isolator chip being installed in the chip accommodating hole and positioned by the positioning corners.

2. The integrated optical assembly structure as claimed in claim 1, wherein the pressing block includes a first pressing block and a second pressing block, an electrical clearance is defined between the first pressing block and the second pressing block, the first pressing block is fixedly connected to the front metal cover, the plug core positioning hole and the chip accommodating hole are defined in the second pressing block.

3. The integrated optical assembly structure as claimed in claim 1 or 2, wherein the positioning corners are each at a right angle.

4. The integrated optical assembly structure as claimed in claim 1, wherein at least two of the positioning corners are arranged diagonally.

5. The integrated optical assembly structure as claimed in claim 3, wherein the number of the positioning corners of the chip accommodating hole is four, and the positioning corners are arranged at four corners of the chip accommodating hole.

6. The integrated optical assembly structure as claimed in claim 5, wherein the chip accommodating hole has a square shape.

7. The integrated optical assembly structure as claimed in claim 5, wherein the four positioning corners the chip accommodating hole are connected through a circular arc surface.

8. A processing method for the integrated optical assembly structure as claimed in any one of claims 1-6, comprising the following steps of:

step 1, material preparation: selecting and putting a Φ5.5 round bar material into a dual spindle CNC bar feeder, and cutting ends of the material;

step 2, drilling of first center hole: adjusting the rotation speed of a spindle of the dual spindle CNC bar feeder to 2500 r/min-3500 r/min, ensuring the concentricity of a drill head with the spindle, and positioning a center hole by the Z-axis movement of a 3.0 central drill towards the dual spindle CNC bar feeder, wherein the feed rate of the drill head is 0.02-0.03 mm/round;

step 3, drilling of round hole: switching to a Φ0.35 drill head, ensuring the concentricity of the drill head with the spindle, adjusting the rotation speed of the spindle to 4500 r/min-5500 r/min, performing a drilling operation by the Z-axis movement of the drill head towards the dual spindle CNC bar feeder, wherein the feed rate is 0.01-0.02 mm/round, and the drilling depth is 3.0 mm:

step 4, formation of chip accommodating hole: switching to a Φ0.35 broach, ensuring the concentricity of the broach with the spindle, adjusting the rotation speed of the spindle to 300-800 r/min, forming a square hole by the Z-axis movement of the broach towards the dual spindle CNC bar feeder, wherein the feed rate of the broach is 0.005-0.01 mm/round, and the processing depth is 1.5 mm;

step 5, rough turning: switching to a rough turning tool, adjusting the rotation speed of the spindle to 2000-2500 r/min, and performing a rough turning by the X-axis movement of the rough turning tool towards the dual spindle CNC bar feeder, wherein the feed rate is 0.02-0.03 mm/round, and the reserved space is 0.1-0.2 mm;

step 6, fine turning: switching to a fine turning tool, adjusting the rotation speed of the spindle to 3000-3500 r/min, performing a fine turning by the X-axis movement of the fine turning tool towards the dual spindle CNC bar feeder, wherein the feed rate is 0.01-0.02 mm/round;

step 7, cut-off switching to a cut-off knife, adjusting the rotation speed of the spindle to 2000-2500 r/min, performing a cut-off operation by the X-axis movement of the knife towards the dual spindle CNC bar feeder, wherein the feed rate is 0.01-0.02 mm/round, the reserved cut-off length is 0.1 mm, and it is necessary to clamp an outer periphery of a workpiece stage by a sub-spindle while cutting;

step 8, polishing of cut surface: adjusting the rotation speed of the sub-spindle to 2500-3000 r/min, wherein the feed rate of a cutter is 0.01-0.02 mm/round, and then polishing the cut surface;

step 9, drilling of second center hole: adjusting the rotation speed of the sub-spindle to approximately 2500 r/min-3500 r/min, ensuring the concentricity of the drill head with the sub-spindle of the dual spindle CNC bar feeder, and positioning a center hole by the Z-axis movement of the 3.0 central drill towards the dual spindle CNC bar feeder, wherein the feed rate of the drill head is 0.02-0.03 mm/round;

step 10, drilling of plug core positioning hole: switching to a Φ1.2 drill, ensuring the concentricity of the drill head with the sub-spindle, adjusting the rotation speed of the sub-spindle to 2500 r/min-3500 r/min, and performing a drilling operation by the Z-axis movement of the drill head towards the dual spindle CNC bar feeder, wherein the feed rate is 0.01-0.02 mm/round, and the drilling depth is 0.7 mm; and

step 11, boring: switching to a Φ1.24 boring tool, adjusting the rotation speed of the sub-spindle to 2500 r/min-3500 r/min, and performing a boring operation by the Z-axis movement of the drill head towards the dual spindle CNC bar feeder, wherein the feed rate is 0.01-0.02 mm/round, and the boring depth is 0.7 mm.