CN108247162B - Numerical control small Kong Jidian pole rotation control device and method - Google Patents

Abstract

This application discloses a numerically controlled small hole machine electrode rotation control device, an application method of the device and a numerically controlled small hole machine equipped with such a device, wherein the electrode rotation control device includes a stepping motor, and the stepping motor drives the electrode tube through the rotating head , also includes: a rotor with a central hole, on which a code pattern is formed; a rubber ring arranged in the central hole, and the electrode tube penetrates into the rubber ring; Stator; a line scan camera that is relatively fixed to the stator and cooperates with the coding pattern to detect the rotation speed of the rotor; supplies power to the stator to drive the rotor to rotate, and is connected to the stepper The motor driver of the motor and the drive circuit connected to the line scan camera. The application can effectively improve the processing quality of small holes.

Description

Electrode rotation control device and method for numerically controlled small hole machine

technical field

The present application relates to the field of numerically controlled small hole machines, in particular to a numerically controlled small hole machine electrode rotation control device, an application method of the device, and a numerically controlled small hole machine equipped with such a device.

Background technique

CNC electric machining small hole machine (hereinafter referred to as small hole machine) is a kind of electric discharge machine tool, which uses a continuously moving slender hollow copper tube as a tool electrode (hereinafter referred to as electrode), and passes through the medium that passes through the hole of the copper tube. (working fluid) discharges with the workpiece, and performs pulse spark discharge on the workpiece to etch the metal to achieve the purpose of perforation. This equipment is mainly used for processing microscopic holes in conductive materials such as superhard steel and cemented carbide. EDM erosion machining is the core part of CNC small hole machine. Its main functions are: 1. Adjust the feed speed of electrode processing according to the gap voltage to control the size of the discharge gap; 2. Rotary liquid supply device (rotary head, guide ) to achieve electrode rotation and high-pressure liquid feeding. Electrode numerical control feed control technology and spark gap voltage acquisition technology have been significantly improved after years of development, and various problems caused by rotating devices have become the main factors affecting product quality.

The hole positioning accuracy of the small hole machine can reach ±1μ, while the accuracy error caused by the rotation processing is greater than ±5μ, and the shape of the processed hole is irregular, so the innovation of the rotation control technology has become the key technology to be solved urgently for the CNC small hole machine question.

The rotary head of the small hole machine has two functions of electrode rotation and high-pressure liquid supply. During the processing of micro-holes (0.3-3mm in diameter), the electrode rotates under the action of the rotary head. The reaction force of the high-pressure and high-speed working fluid medium is offset; on the other hand, the high-pressure flowing working fluid flows out of the hole according to the helical trajectory on the wall of the small hole, like a hydrostatic bearing, so that the electrode tube is "suspended" in the center of the hole, It is not easy to produce short circuit. Therefore, the stability of electrode rotation is an important factor affecting the efficiency and quality of small hole machining.

Existing rotating mechanism (as Fig. 1) comprises stepper motor (hereinafter referred to as motor), synchronous belt, gear, rotating shaft, bearing, electrode chuck and electrode. The electromechanical machining of small holes belongs to the non-contact machining between the electrode and the workpiece. The ideal state of machining is that when the electrode (30cm long and thin hollow tube) is fed along the axial direction, there should be no shaking when rotating. Due to factors such as the force on the rotating shaft, uneven distribution of electrode mass, and limited electrode stiffness, the electrode shakes greatly when rotating, and the guide on the guide frame must be used to limit the shake (the diameter of the inner hole of the guide is larger than the diameter of the electrode). Finite often causes serious consequences such as large aperture, irregular shape, surface damage, or deviation of upper and lower apertures. At the same time, due to the excessive shaking of the electrode, the gap discharge is out of control, and even causes a short circuit between the electrode and the workpiece, which seriously affects the processing quality and efficiency. The current small hole machine rotary liquid supply device mainly has the following shortcomings:

1. Because the electrode (that is, the electrode tube) is slender and hollow, and the mass distribution of the electrode is uneven, the electrode shakes when it rotates, but the passive limiting effect of the guide still exists. In addition, the "contact" between the electrode and the guide produces a new resistance moment, which turns the large-amplitude shaking into a small-amplitude, fast-frequency, and chaotic trajectory, which directly affects the shape, dimensional accuracy and processing efficiency of the processed hole.

2. Since the high-pressure liquid supply parts must be installed in the upper part of the rotary head, direct motor shaft drive cannot be used, and synchronous belt drive must be used. The radial load of the synchronous belt pressing force on the rotating shaft is relatively large, the rigidity of the rotating shaft (because the electrode must pass through the rotating shaft, and the rotating shaft is not solid), the supporting force of the bearing, and the disturbance of the synchronous belt transmission, etc., will cause the electrode to rotate. Shaking occurs evenly, which directly affects the shape, dimensional accuracy and processing efficiency of the processed hole.

3. Since the torque of dragging and rotating acts on the upper part of the electrode, and the electrode itself is slender and hollow, when the processing end (the lower part of the electrode) is disturbed by various small resistances, its rotation trajectory will change, directly affecting the shape of the processing hole, Dimensional accuracy and processing efficiency.

4. Because the electrode is in the small hole of the workpiece during processing, the monitoring and abnormal handling mechanism cannot be installed, and the stepping motor that drags and rotates runs at a constant speed mode (electromagnetic torque adaptive load capacity). Once the electrode shakes too much or "Abnormal" contact will not only seriously affect the quality of the processed workpiece, but even cause the entire workpiece to be scrapped.

5. Due to the difficulty of predicting the loss of the electrode during processing, it is impossible to accurately judge whether the through hole is processed when processing a certain depth hole, resulting in low processing efficiency of the system, the through hole is not pierced or seriously affects the processing quality of the next hole, etc. As a result, through-hole monitoring has always been a technical problem that plagues the automatic processing of small hole machines.

The above-mentioned problems have not been effectively solved for many years. Therefore, improving the existing small hole machine rotary processing device, improving the level of rotation control and monitoring technology, and solving the above problems are of great significance to the technological progress of numerical control small hole machine.

Contents of the invention

The purpose of this application is: in the existing small hole machining process, the electrode rotates under the action of the rotating head, and when the electrode shakes, the guider is used to limit the shaking range. As the manufacturing industry has higher and higher requirements on the precision of parts, this passive limiting method can no longer meet the production needs, and the innovation of rotation control technology has become a key technical problem to be solved urgently for CNC small hole machines. In this regard, this application proposes a method with The electrode rotation control device of CNC small hole machine with good processing stability, processing status monitoring and through hole detection function.

The technical scheme of the application is:

A numerically controlled small hole machine electrode rotation control device, including a stepping motor, the stepping motor drives an electrode tube through a rotating head, and also includes:

A rotor with a central hole on which a coding pattern is made;

a flexible rubber ring arranged in the central hole, and the electrode tube is inserted into the rubber ring;

a stator cooperating with said rotor;

a line scan camera that is relatively fixed to the stator and cooperates with the coding pattern to detect the rotational speed of the rotor; and

A driving circuit that supplies power to the stator to drive the rotor to rotate, and is connected to the motor driver of the stepping motor and the line scan camera.

On the basis of the above-mentioned technical solution, the numerical control small hole machine electrode rotation control device of the present application also includes the following preferred solutions:

The inner diameter of the rubber ring is larger than the outer diameter of the electrode tube.

The inner diameter of the rubber ring is 10 μm larger than the outer diameter of the electrode tube.

Of course, the rubber ring and the electrode tube can also be in direct contact with each other.

Several protrusions are formed on the inner hole wall of the rubber ring.

The rotor is a disc-shaped structure;

The stator includes:

the first upper iron core coil and the second upper iron core coil arranged radially symmetrically on two opposite sides above the rotor,

a first lower iron core coil and a second lower iron core coil radially symmetrically arranged on two opposite sides below the rotor, and

permanent magnets arranged on the sides of said rotor;

The first upper iron core coil is arranged directly above the first lower iron core coil, and the second upper iron core coil is arranged directly above the second lower iron core coil.

The stator also includes permanent magnets disposed at sides of the rotor.

Several protrusions are formed on the inner hole wall of the rubber ring.

The coding pattern includes eight pattern areas uniformly distributed along the circumferential direction and with different patterns.

The motor driver of the stepping motor, the driving circuit and the line scan camera are all connected to the circuit of the numerical control system of the numerical control small hole machine.

A numerically controlled small hole machine, comprising the electrode rotation control device of the numerically controlled small hole machine with the above-mentioned structure.

The application method of the above-mentioned numerically controlled small hole machine electrode rotation control device includes: when not processing, setting the coil current of the stator to be 1, and as the hole depth increases, the coil current gradually becomes larger, and when the processing hole part conducts When the through hole is formed, all the working fluid flows out from the bottom of the through hole. At this time, the resistance torque suddenly decreases and the speed increases, and the coil current after adjustment and stabilization is equivalent to the value of I when no processing is performed. It can be determined that the through hole has been formed.

The advantages of this application are:

1. According to the characteristics of small hole machine rotary processing, this device designs two rotary drive support structures, upper and lower, for the slender hollow electrode. Through the adjustment of high-precision speed measurement and control system, the rotation speed of the "lower" rotary electrode is always servo-tracked. The upper end" rotates the electrode speed, so that the rotation control device is cleverly used to compensate the load disturbance, which greatly improves the stability of the electrode rotation, not only ensures the shape and dimensional accuracy of the machining hole, but also helps to control the gap discharge and reduce the short-circuit invalid processing time. The upper and lower rotary drives are used to release the functional coupling. The power drive part is realized by the rotary head; the guidance and overcoming the micro disturbance are completed by the rotary guide control device, and the coordinated rotation between the two subtly solves the problem of electrode processing stability.

2. In addition, the rotation control device also has the function of detecting "abnormal" conditions in processing. Utilizing this patent can improve the machining quality and efficiency of numerical control small hole machining, and has certain practical value and economic benefit.

3. The device can also identify the moment when the "quasi" through-hole appears, which solves the problem of through-hole detection of the automatic small hole machine, improves the processing efficiency of the system, and avoids the consequences of not piercing the through-hole or affecting the processing quality of the hole. .

4. The inner diameter of the rubber ring is slightly larger than the outer diameter of the electrode tube. Under normal circumstances, the electrode tube and the rubber ring are in a non-contact state, and the rubber ring rotates synchronously with the rotor, and the speed of the rubber ring and the speed of the electrode tube are always the same. be consistent. If the electrode tube shakes normally, the electrode tube will be in slight contact with the rubber ring, and the vibration energy of the electrode tube will be absorbed by the buffer deformation of the rubber ring. Because the speed of the rubber ring and the electrode tube is always consistent, even if the electrode tube touches the rubber ring, and there will be no relative circumferential displacement between the electrode tube and the rubber ring, and the electrode tube will not be subject to circumferential torsional force, and the electrode tube will return to normal rotational motion under the rotation and guidance of the rotor and the rubber ring.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the application is further described:

Fig. 1 is the overall principle diagram of numerically controlled hole machine in the embodiment of the present application;

Fig. 2 is a schematic structural view of the electrode rotation control device of the numerical control small hole machine in the embodiment of the present application;

Fig. 3 is a schematic structural diagram of the encoding pattern on the rotor in the embodiment of the present application;

Fig. 4 is a schematic diagram of the structure of the numerically controlled small hole machine electrode rotation control device installed with a bracket in the embodiment of the present application;

Among them: 1-rotor, 2-rubber ring, 3-electrode tube, 4-stator, 401-the first upper iron core coil, 402-the second upper iron core coil, 403-the first lower iron core coil, 404-the first Two lower iron core coils, 405-permanent magnet, 5-coded graphics, 501-digital graphics, 502-analog images, 6-line scan camera.

Detailed ways

Fig. 1 shows a specific embodiment of this numerically controlled small hole machine of the present application, same as the traditional numerically controlled small hole machine, it also includes: electrode tube 3, stepper motor, numerical control system, high pressure liquid feeder etc. part. Wherein the stepper motor is connected with the electrode tube 3 through a rotating head (or electrode chuck) to drive the electrode tube 3 to rotate. The electrode tube 3 is vertically arranged, the rotating head is located at the upper end of the electrode tube 3, and the stepping motor drives the rotating head by means of a synchronous belt and a synchronous wheel.

The key improvement of this embodiment is that it is also equipped with a CNC small hole machine electrode rotation control device, as shown in FIG. 2 , the device includes a rotor 1 , a stator, a rubber ring 2 and a line scan camera 6 . Among them: the rotor 1 has a central hole with a through-hole structure, the soft rubber ring 2 is fixedly embedded in the central hole, the electrode tube 3 is inserted into the rubber ring 2, and the rotor 1 is made with a special coding pattern 5 (used to mark the rotor rotation angle). The stator cooperates with the rotor 1, and the coils of the stator are energized to make the rotor rotate. The line scan camera 6 is relatively fixed to the stator, and is used to scan the code pattern 5 on the rotor 1 to detect the rotation speed of the rotor 1 . The driving circuit supplies power to the stator to drive the rotor 1 to rotate, and the driving circuit is connected with the motor driver circuit of the stepping motor. The line scan camera 6 is connected with the drive circuit to feed back the detected rotor speed to the drive circuit.

The motor driver, drive circuit, and line scan camera 6 of the above-mentioned stepping motor are all connected to the circuit of the numerical control system of the numerical control small hole machine itself, and the operating states of the three are uniformly controlled by the numerical control system. It can be seen that in this embodiment, the circuit connection among the stepper motor, the drive circuit and the line scan camera 6 is realized by means of the numerical control system of the numerical control small hole machine itself.

In this embodiment, the above-mentioned rotor 1 is a disc-shaped structure, which is horizontally arranged at the lower end of the electrode tube 3, and preferably as close as possible to the workpiece to be processed.

The above-mentioned stator includes: a first upper iron core coil 401 and a second upper iron core coil 402 radially symmetrically arranged on two opposite sides above the rotor 1, and a first lower iron core coil radially symmetrically arranged on two opposite sides below the rotor 1 403 and the second lower iron core coil 404, the permanent magnet 405 arranged on the side of the rotor 1. The aforementioned first upper iron core coil 401 is arranged directly above the first lower iron core coil 403 , and the second upper iron core coil 402 is arranged directly above the second lower iron core coil 404 .

In this embodiment, the inner diameter of the above-mentioned rubber ring 2 is preferably slightly larger than the outer diameter of the electrode tube 3. Generally speaking, the inner diameter of the rubber ring is 10 μm larger than the outer diameter of the electrode tube. . In this way, in general, the electrode tube 3 and the rubber ring 2 are in a non-contact state (like a contact and non-contact state), and the rubber ring 2 rotates synchronously with the rotor, and the speed of the rubber ring 2 is the same as that of the electrode tube 3. The rotational speed is always the same. If the electrode tube 3 shakes normally, the electrode tube 3 will be in slight contact with the rubber ring 2, and the vibration energy of the electrode tube 3 will be absorbed by the buffer deformation of the rubber ring. When the rubber ring is touched, there will be no relative circumferential displacement between the electrode tube and the rubber ring, and the electrode tube will not be subject to circumferential torsional force, and the electrode tube 3 will return to normal rotational motion under the action of the rotor rotation guide.

The reason why the inner diameter of the rubber ring 2 is set slightly larger than the outer diameter of the electrode tube 3 is to prevent the rubber ring 2 from being in too tight contact with the electrode tube 3 and there is a large static friction force, so that the axial direction of the electrode tube 2 is not used. The feeding of the electrode tube is prone to jamming; at the same time, once the rotation speed of the rubber ring 2 and the electrode tube 3 deviates slightly, the lower end of the electrode tube will be subject to a certain circumferential torsional force.

Of course, we can also set the inner diameter of the rubber ring to the same value as the outer diameter of the electrode tube, so that the rubber ring and the electrode tube are in direct and slight contact.

There are many tiny protrusions formed on the inner hole wall of the above-mentioned rubber ring 2 , and the outer wall surface of these electrode tubes 3 will touch the aforementioned protrusions when the electrode tube shakes slightly. The aforesaid protrusions may be in a corrugated structure, or in an arrayed dot-shaped protrusion structure. On the one hand, these protrusions are used to increase buffer absorption, and on the other hand, the torque required for rotation and guidance is very small, and there is no need for a large frictional drag torque. The electrode tube 3 rotates under the action of the rotating head, and the rotor of the device rotates synchronously with the rotating head. Normally, there is no interaction force between the rotor and the electrode tube. Most of the shaking is not "abnormal" small shaking, the energy of the shaking is absorbed by the buffer of the rubber ring, and at the same time, the normal rotation motion is restored under the action of the rotor rotation guide; once the electrode tube shakes too much and the contact with the workpiece is scratched When it is "abnormal", the resistance torque will increase significantly, and the speed will decrease rapidly. The line scan camera connected to the drive circuit detects the change in speed, and the drive circuit immediately stops processing and prompts an alarm.

The rotor of the device is made of aluminum alloy material, which is very light in weight and in order to avoid the center electrode tube, the power torque is introduced from the outer ring part of the rotor. The specific method is as follows: a stable sinusoidal alternating signal is generated by the circuit in the numerical control system, and the signal is output to the excitation coil after power amplification, and the alternating power signal generates alternating magnetic flux in the iron core and eddy current on the rotor; The other signal is amplified and adjusted by program control, and then output to the adjustment coil after power amplification, which also generates alternating magnetic flux in the iron core and eddy current on the rotor. The alternating magnetic flux and eddy current generated by the excitation coil and the adjustment coil interact on the rotor to form an electromagnetic torque to drive the rotor to rotate. When the magnetic flux generated by the permanent magnet is cut by the rotating rotor, it interacts with the induced current generated in the rotor to form a braking torque, so that the rotor speed remains proportional to the electrical signal power. The rotation speed is adjusted by changing the coil current through the D/A output. The larger the current, the higher the rotation speed. The use of symmetrical core coil groups is to ensure the radial load balance of the rotating shaft, and at the same time, the symmetrical two sets of core coils also increase the output power.

Due to the particularity of small hole processing, the processing status can only be monitored through the rotor speed. Therefore, this device uses a line scan camera to identify the coded pattern 5 to achieve non-contact, high-precision angular displacement measurement. The specific method is as follows: as shown in Figure 3, there are two kinds of laser direct writing lithography patterns on the peripheral annular belt of the rotor 1, one is a linear digital pattern 501, which represents the current measurement area, and this design divides the rotor into 8 areas (a sector with a central angle of 45 degrees is a partition), in order to allow the line array sensor to identify the current measurement partition, three circular lines with different radii are used for encoding, and 8 kinds of encoding patterns can be combined, in which the outer circular line represents the highest position and the middle circular line represents the second The high position and the inner ring line represent the lowest position, such as: no pattern at all represents the 0 zone, three lines all represent the 7 zone, and so on; the other is the analog figure 502 corresponding to the radial angle (the longest radial direction of the figure is L), in In each partition (for the convenience of drawing, only one of the partitions is shown in Fig. 3 for simulation graphics), use the simulation graphics method to establish the corresponding mapping relationship between the angle and the radial length of the arc, that is, every 0.45 degrees its radial The length increases by L/100 length units, when the angle increases to 45 degrees, its radial length graph increases to L. When the line scan camera 6 (CCD) collects a radial line array image information, the three inner circle points determine the current measurement area, and the radial length of the outer analog figure corresponds to the angle value in the area, through the measurement area and the area The absolute angle information can be obtained accurately, and the angle change per unit time can be used to calculate the angular velocity or rotational speed. During normal processing, the resistance torque on the electrode tube changes relatively little. Once the electrode tube "abnormally" touches the workpiece, the resistance torque will increase significantly and the speed will decrease rapidly. Therefore, as long as this information is quickly captured, the Effectively adopt corresponding control strategies.

It can be seen that the coding pattern 5 includes eight pattern areas uniformly distributed along the circumferential direction and with different patterns, and each pattern area is composed of the above-mentioned linear digital pattern and analog pattern.

The rotating head drives the electrode to rotate at a constant speed mode. Due to various reasons, the electrode shakes during the rotation. In order to keep the electrode as a whole in a synchronous rotation state, it is necessary to drive the slender electrode at two points up and down, that is, to install it on the guide frame. A rotary control. Usually, the shaking energy caused by various reasons (such as uneven electrode quality, etc.) is small, and the synchronous rotation state can be guaranteed through the active compensation of the rotation control device (the rotation speed of the lower rotor auxiliary electrode is always servo-tracked and the upper rotating head drags the electrode. Tube speed), the method is as follows: This device uses a two-phase stepping motor, and its speed can be controlled by pulse frequency. The speed calculation formula (1) is as follows:

Among them: x: driver subdivision multiple; θ: inherent step angle.

According to the processing speed V, the corresponding fixed frequency f pulse is input to the stepper motor driver, and the driver and the stepper motor drive the electrode tube to rotate at a constant speed V; at the same time, the lower part of the electrode tube assists the servo tracking speed V in the rotation control device to make it rotate Stance remains consistent with the upper to eliminate stress between the upper and lower. In this way, there are two rotating driving support points on the upper and lower sides of the elongated hollow electrode, which ensures the linearity of the electrode rotation and compensates for various load disturbances, ensuring the stability of the electrode rotation.

The processing speed of the electrode tube is not high (20-120 r/min), and the rotating head works in the constant speed mode during processing. However, in order to ensure the coordinated tracking stability of the rotation control device when starting or shifting, the stepper motor must follow the set Acceleration and deceleration curve speed regulation.

The disturbances caused by the processing end mainly include the following types: due to the two-point drive support during unprocessed, there is almost no no-load shaking of the electrode. When the electrode is falling and touching the electrode, the contact force and discharge force cause abnormal speed, which is detected by the rotation control device. And quickly withdraw the electrode to avoid damage to the workpiece hole. After that, the normal processing starts with a low speed drop; during normal processing, as the processing depth increases, the pressure of the working fluid on the electrode tube wall also gradually increases. Speed V; the disturbance caused by the discharge force and the reaction force of the working fluid during normal processing will also be offset by the action of the rotating control device; when the electrode tube head is broken or other reasons make the rotating electrode contact with the workpiece "abnormally", it will cause The resistance torque increases significantly, and the speed decreases rapidly. At this time, the numerical control system will immediately turn off the rotation and high-frequency power supply, and quickly retract the electrode to avoid serious consequences of scrapping the workpiece.

In the deep hole machining of small hole machines, the compensation method is usually used to set the machining depth, but the loss of the electrode tube is affected by factors such as the machining material and cannot be accurately calculated. In actual machining, the through hole is often not pierced (blind hole). In order to avoid this phenomenon, the operator must increase the depth compensation, which causes the coordinates of the CNC system to not reach the set depth after most holes are pierced, resulting in the situation of continuing to "dry" a certain depth. Because the CNC small hole machine is mainly used for batch hole processing, this situation seriously affects the processing efficiency. This device is used for the through-hole detection method as follows: when not processing, the rotation control device coil current (that is, the current of the stator coil) is 1, and the coil (stator coil) current will gradually increase along with the increase of the hole depth, when When the processed hole is partially conducted to form a "quasi" through hole, the liquid (that is, the working fluid) will all flow out from the bottom of the hole. At this time, the resistance torque will suddenly decrease and the speed will increase. The value of I is the same during processing, so it can be judged that the "quasi" through hole has been formed, the numerical control system sends out the command to open the auxiliary liquid supply solenoid valve in time, and the working fluid is supplied to the processing hole from the external liquid supply pipe, ensuring that the "quasi" through hole is processed to Processing quality at the through-hole stage.

Certainly, the above-mentioned embodiments are only for illustrating the technical conception and characteristics of the present application, and the purpose is to enable people to understand the content of the present application and implement it accordingly, and not to limit the protection scope of the present application. All equivalent changes or modifications made according to the spirit of the main technical solutions of this application shall fall within the scope of protection of this application.

Claims (8)

1. The utility model provides a numerical control is little Kong Jidian utmost point rotary control device, includes step motor, step motor passes through swivel drive electrode tube (3), its characterized in that still includes:

a rotor (1) with a central hole, wherein a coding pattern (5) is manufactured on the rotor (1);

a flexible rubber ring (2) arranged in the central hole, wherein the electrode tube (3) penetrates into the rubber ring (2);

a stator cooperating with the rotor (1);

a linear array scanning camera (6) which is relatively fixed with the stator and is matched with the coding pattern (5) for detecting the rotating speed of the rotor (1); and

the driving circuit is used for supplying power to the stator so as to drive the rotor (1) to rotate and is connected with a motor driver of the stepping motor and the linear array scanning camera (6);

the rotor (1) is of a disc-shaped structure;

the stator includes:

a first upper core coil (401) and a second upper core coil (402) which are radially symmetrically arranged on two opposite sides above the rotor (1),

a first lower core coil (403) and a second lower core coil (404) which are radially symmetrically arranged on opposite sides below the rotor (1), and

a permanent magnet (405) arranged on the side of the rotor (1);

the first upper core coil (401) is arranged directly above the first lower core coil (403), and the second upper core coil (402) is arranged directly above the second lower core coil (404);

the motor driver of the stepping motor, the driving circuit and the linear array scanning camera (6) are all connected with a numerical control system circuit of the numerical control pinhole machine.

2. The numerical control small Kong Jidian pole rotation control device according to claim 1, wherein the inner diameter of the rubber ring (2) is larger than the outer diameter of the electrode tube (3).

3. The numerical control small Kong Jidian pole rotation control device according to claim 2, wherein the inner diameter of the rubber ring (2) is 10 μm larger than the outer diameter of the electrode tube (3).

4. A numerical control small Kong Jidian pole rotation control device according to claim 1, characterized in that the rubber ring (2) is in contact fit with the electrode tube (3).

5. The numerical control small Kong Jidian pole rotation control device according to claim 2, 3 or 4, wherein a plurality of protrusions are formed on the inner hole wall of the rubber ring (2).

6. The numerical control small Kong Jidian pole rotation control device according to claim 1, wherein the code pattern (5) includes eight pattern areas uniformly distributed in the circumferential direction and having different patterns.

7. A numerical control small hole machine, characterized by comprising the numerical control small Kong Jidian pole rotation control device according to any one of claims 1 to 6.

8. A method of using the numerical control small Kong Jidian pole rotation control device according to any one of claims 1 to 6, wherein the coil current of the stator is set to I when the machining is not performed, the coil current is gradually increased with an increase in the hole depth, and when the machining hole is partially conducted to form the through hole, the working fluid is entirely discharged from the bottom of the through hole, and the abrupt resistance torque reduction and the rotation speed increase occur at this time, and the coil current after the adjustment is stabilized is equivalent to the value of I when the machining is not performed, so that it can be determined that the through hole has been formed.

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