JP2014222637A - Electron beam machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electron beam machine with beam current detection means, capable of preventing degradation in measurement accuracy of a beam current even when the permeability of a magnetic substance constituting a beam current detection section changes with a temperature rise.SOLUTION: The beam current detection means 1 includes: a beam current detection coil 4 and a correction coil 5 wound a peripheral section of a core 2 formed from magnetic material; an integrator 6 connected with the beam current detection coil 4; a sine-wave generator 7 and a calculation circuit 8 connected with the correction coil 4; and gain adjustment means 9 connected with the integrator 6 and the calculation circuit 8.

Description

  The present invention relates to an electron beam processing machine used for welding or the like, and more particularly to an electron beam processing machine using a pulse beam.

There is a processing machine using an electron beam that performs welding with a narrow beam diameter and less thermal influence than arc welding or the like. Some electron beam processing machines use a DC electron beam, and others use a pulse beam obtained by repeatedly turning an electron beam on and off.
In recent years, due to the digitization of automobiles, etc., the welding of electronic parts in this field has eliminated the thickening of the beads on the workpiece surface, and an electron beam using a pulse beam that can obtain a bead with less thermal influence on the wedge. A processing machine is often used (see, for example, Patent Document 1).

In an electron beam processing machine using a pulse beam, pulse control that can finely control the amount of heat input to the joint is important, and in order to improve the accuracy of the pulse beam, there is a wide-band, high-precision, stable beam current detection means. is necessary.
As the beam current detection means, for example, there is one using a current transformer. Specifically, a single ferrite core, two or more sets of forward winding coils and reverse winding coils wound around the ferrite core, a noise elimination circuit, and a conductive material that accommodates the ferrite core, forward winding coils, and reverse winding coils. There is a beam current detecting means composed of a sex case.

  This beam current detection means inputs the output signal from the forward winding coil and the reverse winding coil, which is proportional to the magnetic field change in the ferrite core generated when the electron beam (current), which is a charged particle, passes, to the noise elimination circuit. In addition, the in-phase noise included in the output signal is removed to increase the measurement accuracy of the beam current. In addition, a damping resistance film is provided inside the conductive case to attenuate ringing caused by the electron beam, thereby eliminating the influence of ringing and increasing the measurement accuracy of the beam current (see, for example, Patent Document 2).

JP 2012-146471 A (page 6-7, FIG. 1) Japanese Patent No. 4979500 (page 4, FIGS. 1 and 3)

An electron beam processing machine using a pulse beam described in Patent Document 1 includes a processing unit including an electron gun and a power supply unit, and a beam current serving as a beam current detection unit is provided outside the casing of the processing unit. A detection circuit is provided.
In an electron beam processing machine using a pulse beam, it is necessary to improve the response of the feedback control of the beam current in order to improve the quality of the joint in the workpiece that is the object to be processed. It is indispensable to install in the housing of the processing part.

  However, when the beam current detection means described in Patent Document 2 with high beam current measurement accuracy is installed in the housing of the processing part, the ferrite constituting the beam current detection part of the beam current detection means due to the temperature rise of the processing part There has been a problem that the temperature of the core rises, the permeability of the ferrite core changes, and the measurement accuracy of the beam current decreases.

  The present invention has been made in order to solve the above-described problems, and the purpose of the present invention is to set the magnetic permeability of a magnetic material such as a ferrite core that is installed in a processing portion and constitutes a beam current detection portion due to a temperature rise. To obtain an electron beam processing machine equipped with a beam current detection means that does not deteriorate the measurement accuracy of the beam current even if it changes.

  In the electron beam processing machine according to the present invention, a processing unit in which a workpiece is installed has a housing, an electron gun housed in the housing, and a pulse beam emitted from the electron gun installed in a lower portion of the housing. A converging lens for converging on the workpiece, a beam current detecting means for detecting the beam current, and a pulse control circuit for controlling the pulse beam at a high frequency, and the beam current detecting means has a surrounding portion around the through hole. A magnetic core, a beam current detection coil wound around the core, a correction coil wound around the core, and a beam current detection coil voltage connected to the beam current detection coil A sine wave generator that is connected to the correction coil and outputs a standard signal, is connected to the correction coil and measures the correction coil voltage, and is proportional to the reciprocal of the correction coil voltage Is connected to the calculation circuit that outputs the measured value, the integrator, and the calculation circuit. Based on the output of the calculation circuit, the beam current detection coil voltage output from the integrator is corrected and a correction signal is output to the pulse control circuit. Gain adjusting means, and the beam current passes through the through hole of the core around which the beam current detection coil is wound.

  Since the electron beam processing machine according to the present invention is configured as described above, even if the magnetic permeability of the magnetic material constituting the beam current detecting means changes due to the temperature rise, it depends on the temperature rise of the magnetic material. Therefore, it is possible to measure the beam current with high accuracy and stability, and it is possible to improve the quality of the joint portion in the workpiece that is the workpiece.

It is a schematic diagram which shows the structure of the electron beam processing machine concerning Embodiment 1 of this invention. It is a schematic diagram which shows the structure of the beam current detection means of the electron beam processing machine concerning Embodiment 1 of this invention. It is a schematic diagram which shows the structure of the electron beam processing machine concerning Embodiment 2 of this invention. It is a schematic diagram which shows the structure of the beam current detection means of the electron beam processing machine concerning Embodiment 3 of this invention. It is a schematic diagram which shows the structure of the beam current detection means of the electron beam processing machine concerning Embodiment 4 of this invention.

Embodiment 1 FIG.
FIG. 1 is a schematic diagram showing a configuration of an electron beam processing machine according to Embodiment 1 of the present invention.
FIG. 2 is a schematic diagram showing the configuration of the beam current detection means of the electron beam processing machine according to Embodiment 1 of the present invention.
As shown in FIG. 1, an electron beam processing machine 100 that processes with a pulsed electron beam (referred to as a pulse beam) according to the present embodiment includes a processing unit on which a workpiece is installed, a power supply unit that supplies electricity to the processing unit, It has.

The processing unit includes a casing 19, an electron gun 12 that emits a pulse beam 11, and a workpiece that is installed in the lower portion of the casing 19. A convergence lens 17 that converges to 30; a beam current detection means 1 that detects a pulse beam current (referred to as a beam current); and a pulse control circuit 20 that controls the pulse beam 11 at high frequency.
FIG. 1 also shows a pulse beam 11 and a workpiece 30 to which the pulse beam 11 is irradiated.

The beam current detection unit 1 and the pulse control circuit 20 to which a signal from the beam current detection unit 1 is input are installed in the upper casing 19a above the electron gun installation unit 19b of the casing 19. . The pulse control circuit 20 generates a pulse voltage based on the beam current detection signal output from the beam current detection means 1 and the command signal, and the pulse power beam 11 is transmitted at a high frequency by a bias power source 21 described later by feedback control. Control.
In the present embodiment, the upper casing portion 19a is filled with the insulating oil 18.

The electron gun 12 is provided with a cathode 14 that emits thermoelectrons, a heater 13 that heats the cathode 14 to generate thermoelectrons, and a hole through which the pulse beam 11 passes, and the thermoelectrons generated at the cathode 14. And the bias electrode 15 disposed between the cathode 14 and the anode 16.
The material of the cathode 14 is lanthanum hexabolite (LaB ₆ ), and the cathode 14 is heated to 1550 ° C.

The power supply unit is connected to a heater power supply 22 that supplies a current for generating heat from the heater 13, a bias power supply 21 that is connected to the bias electrode 15 and controls the current of the pulse beam 11, a cathode 14, and an anode 16. And an accelerating power supply 23 for applying a voltage for accelerating electrons in the anode direction.
In the electron beam processing machine 100 of the present embodiment, for example, the beam current is 0 to 0.1 A, and the pulse frequency is 10 kHz or less.

As shown in FIG. 2, the beam current detecting means 1 used in the electron beam processing machine 100 of the present embodiment includes a ring-shaped ferrite core 2 that is a single hollow circle and a ferrite core 2 that is a magnetic material. A beam current detection coil 4 wound around the ring portion and a correction coil 5 wound around the ring portion of the ferrite core 2 are provided.
That is, in the beam current detection unit 1, a correction coil 5 is wound around the ring portion of the ferrite core 2 in the beam current detection unit 1 a including the ferrite core 2 and the beam current detection coil 4.

The beam current detection coil 4 is connected to an integrator 6 that measures an induced voltage (referred to as a beam current detection coil voltage) V _ib of the beam current detection coil 4.
Further, the correction coil 5 measures a sine wave generator 7 that outputs a standard signal and an output voltage (referred to as correction coil voltage) V _s from the correction coil 5, and the correction coil voltage V _s It is connected to a calculation circuit 8 that outputs a value proportional to the reciprocal.
Further, the integrator 6 and the calculation circuit 8 are connected to the gain adjustment unit 9, and the gain adjustment unit 9 outputs the beam current detection coil voltage V _ib output from the integrator 6 from the calculation circuit 8. And the gain is adjusted to output a corrected signal to the pulse control circuit 20.

In the beam current detection means 1 of the present embodiment, the ferrite core 2 around which the beam current detection coil 4 forming the beam current detection unit 1a is wound has a through-type current transformer structure.
The ferrite core 2 is, for example, a ring-shaped Mn—Zn-based soft magnetic material.
As shown in FIGS. 1 and 2, the ferrite core 2 has a ring portion surrounding the beam current conducting path 3, that is, the beam current conducting path 3 is inserted into the hole of the ferrite core 2. The beam current 11a flows through the beam current conducting path 3.

The beam current detection unit 1 a detects the beam current 11 a passing through the beam current conduction path 3, and the beam current detection coil voltage V _ib is output from the beam current detection coil 4.
Correction coil 5 detects the correction coil voltage V _s generated by the input of a standard signal having a constant frequency from the sine wave generator 7 which is constant current control, and outputs.
In FIG. 2, the coils 4 and 5 are wound around a part of the ring portion of the ferrite core 2, but actually, the coils 4 and 5 are wound over the entire circumference of the ring portion of the ferrite core 2. Is wound.

In the present embodiment, the number of turns of the beam current detection coil 4 is 400 turns in which the winding resistance of the coil 4 is sufficiently smaller than the input resistance 1 kΩ of the integrator 6 connected to the coil 4. In this case, the DC electric resistance of the beam current detection coil 4 is 4Ω.
However, the number of turns of the beam current detection coil 4 is not limited to 400 turns as long as it is sufficiently smaller than the input resistance of the integrator 6 and a desired induced voltage can be generated.

Further, since the number of turns of the correction coil 5 only needs to detect the voltage, the number of turns is less than that of the beam current detection coil 4 and is 50 turns, and the DC electric resistance of the correction coil 5 is 0. 5Ω.
The number of turns of the correction coil 5 is not limited to 50 turns as long as it is less than the beam current detection coil 4 and does not affect the measurement of the beam current 11a.

Further, the sine wave generator 7 that outputs a standard signal can pass a sine wave current having a frequency of 50 kHz and an amplitude of 1 mA, for example, and the fluctuation rate of the sine wave current is 0.1% or less.
Further, a filter (not shown) excluding the frequency of the sine wave generator 7, for example, 50 kHz, may be installed between the beam current detection coil 4 and the integrator 6. The measurement accuracy of the beam current 11a in the beam current detection coil 4 is further improved.

Next, a mechanism by which the beam current detection means 1 used in the electron beam processing machine 100 of the present embodiment can measure the beam current with high accuracy even when the temperature of the ferrite core changes will be described.
The beam current detection coil voltage V generated in the beam current detection coil 4 when the _Ib beam current 11a flows through the beam current conducting path 3 inserted through the hole of the ferrite core 2 is expressed by the following equation (1). expressed.
V = μ ₀ μA × dI _b / dt (1)
Here, μ ₀ is the permeability of vacuum, μ is the permeability of the ferrite core, dI _b / dt is the time derivative of the beam current, and A is the shape parameter.

The shape parameter A is expressed by the following equation (2).
A = NS / 2πr (2)
Here, N is the number of turns of the beam current detection coil, S is the cross-sectional area of the surface perpendicular to the circumferential direction of the ferrite core, and r is the radius of the inner circumference of the ferrite core.
(1) As apparent from the equation, the beam current detection coil voltage V, the change of the beam current I _b, of course, also a change of the permeability μ of a ferrite core varies.

Since the permeability μ of the ferrite core changes depending on the temperature, when the ambient temperature rises due to the operation of the electron beam processing machine 100, the temperature of the ferrite core 2 changes and the beam current detection coil voltage V changes.
That is, the beam current I _b, since obtained by integrating the beam current detection coil voltage V, the temperature change of the ferrite core 2 refers decreases the measurement accuracy of the beam current I _b of the beam current detecting unit 1a.

Then, the beam current detecting means 1, a method for correcting the variation of the beam current I _b due to the temperature change of the ferrite core 2 is described.
When the standard signal from the sine wave generator 7 is input, the correction coil voltage V _s generated in the correction coil 5 is measured by the calculation circuit 8. Then, the calculation circuit 8 outputs a correction value k, which is calculated based on the correction coil voltage V _s and corrects the beam current detection coil voltage, to the gain adjustment means 9.
The correction value k corresponding to the temperature change of the magnetic permeability μ of the ferrite core is calculated from the reference correction coil voltage V _s0 and the correction coil voltage V _{sT at} a predetermined temperature.

The correction value k is obtained as follows.
When the magnetic permeability of the ferrite core 2 at the reference temperature T ₁ is μ ₁ , the correction coil voltage V _s0 is expressed by the following equation (3).
V _s0 = μ ₀ μ ₁ AωI cos ωt (3)
Here, ω is the angular frequency of the standard signal of the sine wave generator, and t is time.
When the electron beam processing machine 100 is operated, the ambient temperature increases, the temperature of the ferrite core 2 increases from T ₁ to T _2, and the correction coil voltage V _sT when the permeability of the ferrite core 2 becomes μ ₂ is It is represented by the following formula (4).
V _sT = μ ₀ μ ₂ AωI cos ωt (4)

And the correction value k is calculated | required from the following (5) Formula.
k = V _s0 / V _sT
= (Μ ₀ μ ₁ AωI cos ωt) / (μ ₀ μ ₂ Aω I cos ωt)
= Μ ₁ / μ ₂ (5)
The gain adjusting unit 9 to which the correction value k, which is a value inversely proportional to the correction coil voltage V _sT , is input to the beam current detection coil voltage V _Ib corrected based on the correction value k (correction of the beam current detection coil). Output V _o ). The correction voltage _{V o} is expressed by the following equation (6).
V _o = kV _Ib
= (Μ ₁ / μ ₂ ) × μ ₀ μ ₂ A × dI _b / dt
= Μ ₀ μ ₁ A × dI _b / dt (6)

That is, the magnetic permeability of the ferrite core 2 at the reference temperature is obtained in advance by μ ₁ and the correction coil voltage V _s0, and the correction coil voltage V _sT during operation of the electron beam processing machine 100 is measured. it allows compensation value is obtained k calculation circuit 8, based on the correction value k, the gain adjusting unit 9, and outputs the correction voltage V _o of the beam current detection coil.
Electron beam processing machine 100 of the present embodiment, since obtaining the beam current based on the correction voltage V _o of the beam current detection coil, thereby improving the measurement accuracy and stability of the beam current.

In the electron beam processing machine 100 of the present embodiment, when the ambient temperature of the cathode 14 is changed from 20 ° C. to 80 ° C., the measurement error of the beam current amplitude is 1% or less. However, in a similar electron beam processing machine that does not use the beam current detection means 1 of the present embodiment, when the ambient temperature of the cathode 14 increases from 20 ° C. to 80 ° C., the Mn—Zn ferrite core Since the permeability increases 1.4 times, an error of 20% or more occurs in the detected value of the beam current.
That is, the electron beam processing machine 100 according to the present embodiment can measure the beam current 11a with high accuracy and stability without being influenced by the temperature rise of the ferrite core 2 caused by the rise in ambient temperature during operation. Yes, it is possible to improve the quality of the joints in the workpiece that is the workpiece.

Further, since the beam current detecting means 1 of the present embodiment does not use a detection resistor for detecting the beam current, noise is hardly mixed and the noise is 1% or less. Further, when a detection resistor is used for beam current detection, a low-pass filter necessary for noise removal is unnecessary, which is suitable for measurement of a beam current in a high-frequency pulse beam.
That is, the electron beam processing machine 100 of the present embodiment can use a high-frequency pulse beam.

If the beam current detection means having a ferrite core and a coil wound around the ferrite core is provided inside the acceleration power source 23 of the electron beam processing machine, the temperature of the ferrite core hardly increases, and this is caused by the temperature increase of the ferrite core. A reduction in measurement accuracy can be prevented.
A beam current control signal based on the measurement by the beam current detecting means needs to be fed back to the pulse control circuit 20.
However, for transmission of the beam current control signal from the beam current detection means provided in the acceleration power supply 23 on the low voltage side to the pulse control circuit 20 provided on the high voltage side, an optical fiber cable is used for insulation. Therefore, the frequency that can be transmitted is limited to about 10 kHz, and high frequency cannot be transmitted.

  Since the beam current detecting means 1 of the present embodiment is not easily affected by temperature, as shown in FIG. 1, the beam current detecting means 1 is placed in the upper casing portion 19a filled with the insulating oil 18 which is a high voltage portion close to the pulse control circuit 20. The delay of the signal transmitted from the beam current detection means 1 can be reduced, and high-precision control can be performed even with a higher frequency pulse beam.

In the present embodiment, the material of the cathode 14 is lanthanum hexabolite (LaB ₆ ), but may be tungsten (W). In the case of the tungsten cathode 14, since the heating is performed up to 3000 ° C., the change in the ambient temperature becomes large, and the effectiveness of the beam current detecting means 1 of the present embodiment becomes more remarkable.

In this embodiment, the ring-shaped ferrite core uses a Mn—Zn-based material, but a Ni—Zn-based material or other ferrite forming material may be used, or Instead, a ring-shaped core in which electromagnetic steel plates, which are hollow circular magnetic bodies, are stacked may be used, and the same effect can be obtained.
Moreover, the shape of the core made of a magnetic material such as ferrite or electrical steel sheet is not a ring shape if a through-type current transformer structure having a surrounding portion around the through-hole and winding the beam current detection coil 4 can be formed. May be.

Embodiment 2. FIG.
FIG. 3 is a schematic diagram showing the configuration of an electron beam processing machine according to Embodiment 2 of the present invention.
As shown in FIG. 3, the electron beam processing machine 200 that processes with the pulse beam 11 according to the present embodiment uses the beam current detection means 1 between the anode 16 and the converging lens 17, that is, the electron gun 12 and the converging lens 17. And the electron beam processing machine 100 of the first embodiment except that the pulse beam 11 (corresponding to the beam current) passes through the beam current conducting path 3.

  In the electron beam processing machine 200 of this embodiment, the beam current detection means 1 is installed between the electron gun 12 and the converging lens 17, and the temperatures of the pulse beam 11, the anode 16, and the converging lens 17 are detected. Due to the rise, the temperature of the ferrite core 2 of the beam current detecting means 1 rises. However, since the beam current detecting means 1 is the same as that of the first embodiment, the temperature rise of the ferrite core 2 is not affected. It is possible to measure the beam current 11a with high accuracy and stability, and to improve the quality of the joint portion in the workpiece that is the workpiece.

Also in the electron beam processing machine 200 according to the present embodiment, the beam current detection means 1 does not require a low-pass filter necessary for noise removal, and can measure the beam current 11a of the high-frequency pulse beam. Can be used.
In the present embodiment, the beam current detecting means 1 is installed between the electron gun 12 and the converging lens 17. However, if the beam current detecting means 1 is between the electron gun 12 and the work 30, the electron gun 12 and the converging lens 17. It is not limited to between.

Embodiment 3 FIG.
FIG. 4 is a schematic diagram showing the configuration of the beam current detection means of the electron beam processing machine according to Embodiment 3 of the present invention.
As shown in FIG. 4, in the electron beam processing machine according to the present embodiment, the beam current detection means 51 includes a first ferrite core 41 in which the beam current detection coil 4 is wound around a ring portion, and a correction coil 5. A second ferrite core 42 wound around a ring portion, the second ferrite core 42 is disposed adjacent to the first ferrite core 41, and only the hole portion of the first ferrite core 41 is beamed. Except that the current conducting path 3 is inserted, it is the same as the electron beam processing machine 100 of the first embodiment or the electron beam processing machine 200 of the second embodiment.

  In the beam current detection means 51 of the present embodiment, the first ferrite core 41 around which the beam current detection coil 4 forming the beam current detection part 51a is wound has a through-type current transformer structure.

The electron beam processing machine according to the present embodiment also corrects the beam current detection coil voltage, which is an induced voltage of the beam current detection coil 4, according to the temperature change of the ferrite core 41, and therefore depends on the temperature rise of the ferrite core 41. Therefore, it is possible to measure the beam current 11a with high accuracy and stability, and to improve the quality of the joint portion in the workpiece that is the workpiece.
When the beam current detection coil 4 and the correction coil 5 are wound around one ferrite core, the energization of the correction coil 5 slightly affects the beam current detection. In the beam processing machine, the beam current detection coil 4 is wound around the first ferrite core 41 and the correction coil 5 is wound around the second ferrite core 42 in the beam current detection means 51. The temperature can be corrected without affecting the detection, and the beam current 11a can be measured with high accuracy and stability.

Also in the present embodiment, the ring-shaped first and second ferrite cores 41 and 42 are made of Mn—Zn-based material, but Ni—Zn-based material or other ferrite forming materials are used. Alternatively, it may be used instead of the first and second ferrite cores 41 and 42, and may be a ring-shaped core in which electromagnetic steel plates that are hollow circular magnetic bodies are laminated.
In addition, the shape of the first core made of a magnetic material such as ferrite or electromagnetic steel plate can be formed as long as a through-type current transformer structure having a surrounding portion around the through-hole and around which the beam current detection coil 4 can be wound can be formed. It does not have to be in the shape.
In addition, the shape of the second core made of a magnetic material such as ferrite or electromagnetic steel plate can also be a ring shape if a through-type current transformer structure having a surrounding portion around the through-hole and around which the correction coil 5 can be wound can be formed. Not necessarily.

Embodiment 4 FIG.
FIG. 5 is a schematic diagram showing the configuration of the beam current detection means of the electron beam processing machine according to Embodiment 4 of the present invention.
As shown in FIG. 5, in the electron beam processing machine according to the present embodiment, the beam current detection means 61 includes a first ferrite core 41 in which the beam current detection coil 4 is wound around a ring portion, and a correction coil 5. A second ferrite core 42 wound around the ring portion, and the second ferrite core 42 is disposed adjacent to the lower surface of the first ferrite core 41 with the upper surface facing the first ferrite core 41. The electron beam machining machine 100 of the first embodiment or the electron beam machining of the second embodiment except that the beam current conducting path 3 is inserted through the hole of the ferrite core 41 and the hole of the second ferrite core 42. It is the same as the machine 200.

  In the beam current detection means 61 of the present embodiment, the first ferrite core 41 around which the beam current detection coil 4 forming the beam current detection portion 61a is wound and the second ferrite core 41 around which the correction coil 5 is wound. The ferrite core 42 has a through-type current transformer structure.

The electron beam processing machine according to the present embodiment also corrects the beam current detection coil voltage, which is an induced voltage of the beam current detection coil 4, according to the temperature change of the ferrite core 41, and therefore depends on the temperature rise of the ferrite core 41. Therefore, it is possible to measure the beam current 11a with high accuracy and stability, and to improve the quality of the joint portion in the workpiece that is the workpiece.
When the beam current detection coil 4 and the correction coil 5 are wound around one ferrite core, the energization of the correction coil 5 slightly affects the beam current detection. In the beam processing machine, the beam current detection coil 4 is wound around the first ferrite core 41 and the correction coil 5 is wound around the second ferrite core 42 in the beam current detection means 61. The temperature can be corrected without affecting the detection, and the beam current 11a can be measured with high accuracy and stability.

In FIG. 5, the lower surface of the first ferrite core 41 and the upper surface of the second ferrite core 42 face each other, but the upper surface of the first ferrite core 41 and the lower surface of the second ferrite core 42 face each other. May be.
That is, it is only necessary that the first ferrite core 41 and the second ferrite core 42 overlap and are adjacent to each other in the direction in which the hole of the ferrite core passes therethrough.

Also in the present embodiment, the ring-shaped first and second ferrite cores 41 and 42 are made of Mn—Zn-based material, but Ni—Zn-based material or other ferrite forming materials are used. Alternatively, the first and second ferrite cores 41 and 42 may be replaced by a ring-shaped core in which electromagnetic steel plates that are hollow circular magnetic bodies are laminated.
In addition, the shape of the first core made of a magnetic material such as ferrite or electromagnetic steel plate can be formed as long as a through-type current transformer structure having a surrounding portion around the through-hole and around which the beam current detection coil 4 can be wound can be formed. It does not have to be in the shape.
In addition, the shape of the second core made of a magnetic material such as ferrite or electromagnetic steel plate can also be a ring shape if a through-type current transformer structure having a surrounding portion around the through-hole and around which the correction coil 5 can be wound can be formed. Not necessarily.

Embodiment 5 FIG.
The electron beam processing machine for processing with the pulse beam according to the present embodiment includes means for turning off the sine wave generator 7 and the calculation circuit 8 when the beam current detection means generates the pulse beam, and the beam current detection coil. 4 and the integrator 6 are the same as those of the electron beam processing machine of the first embodiment except that no filter except the frequency of the sine wave generator 7 is installed.
In the electron beam processing machine of the present embodiment, when the pulse beam 11 is generated, the sine wave generator 7 and the calculation circuit 8 of the beam current detecting means are off.
However, when the pulse beam 11 is stopped when the workpiece 30 is replaced, the sine wave generator 7 and the calculation circuit 8 are operated, and the correction value k obtained by the calculation circuit 8 is used as the gain adjustment means 9. Enter and memorize.

Then, the beam current detection coil voltage V _Ib of the occurrence of the pulse beam 11 is corrected by the gain adjusting unit 9 based on the correction value k, the correction voltage V _o of the beam current detection coil 4 is output from the gain adjustment means 9 The
Also electron beam machine according to the present embodiment, since obtaining the beam current 11a on the basis of the correction voltage V _o from the beam current detecting means, it is possible to reduce the influence of the temperature rise of the ferrite core 41, and the accuracy of the beam current 11a Measurements Stability is improved, and the quality of the joint in the workpiece that is the workpiece is improved.
Further, the beam current detecting means of the electron beam processing machine according to the present embodiment does not need to be provided with a filter excluding the frequency of the sine wave generator 7, and can be miniaturized.

  It should be noted that the present invention can be freely combined with each other within the scope of the invention, and each embodiment can be appropriately modified or omitted.

  In the electron beam processing machine according to the present invention, the beam current detecting means detects the beam current with high accuracy and stability even when the temperature changes during operation. Used for joining and the like.

1 beam current detection means, 1a beam current detection unit, 2 ferrite core,
3 beam current conduction path, 4 beam current detection coil, 5 correction coil, 6 integrator,
7 sine wave generator, 8 calculation circuit, 9 gain adjusting means, 11 pulse beam,
11a beam current, 12 electron gun, 13 heater, 14 cathode, 15 bias electrode, 16 anode, 17 converging lens, 18 insulating oil, 19 housing, 19a upper housing section,
19b Electron gun installation section, 20 pulse control circuit, 21 bias power supply,
22 heater power supply, 23 acceleration power supply, 30 work, 41 first ferrite core,
42 second ferrite core, 51 beam current detection means, 51a beam current detection section, 61 beam current detection means, 61a beam current detection section,
100, 200 Electron beam processing machine.

Claims (8)

A processing unit in which a work is installed has a housing, an electron gun housed in the housing, and a convergence that converges a pulse beam emitted from the electron gun on the work installed in the lower part of the housing A lens, beam current detection means for detecting a beam current, and a pulse control circuit for high-frequency control of the pulse beam,
The beam current detecting means includes a core made of a magnetic body having a surrounding portion around a through hole, a beam current detection coil wound around the surrounding portion of the core, and a correction wound around the surrounding portion of the core. Coil, an integrator connected to the beam current detection coil and measuring the beam current detection coil voltage, a sine wave generator connected to the correction coil and outputting a standard signal, and connected to the correction coil Is connected to a calculation circuit that measures the correction coil voltage and outputs a value proportional to the reciprocal of the correction coil voltage, the integrator and the calculation circuit, and based on the output of the calculation circuit, A gain adjusting means for correcting the beam current detection coil voltage output from the integrator and outputting a correction signal to the pulse control circuit;
An electron beam processing machine in which the beam current passes through a through hole of the core around which the beam current detection coil is wound. The core of the beam current detection means is formed of a single core, and the beam current detection coil and the correction coil are wound around the periphery of the single core. The electron beam processing machine according to claim 1. The core of the beam current detection means is formed of a first core and a second core, the beam current detection coil is wound around a surrounding portion of the first core, and the second The electron beam machining according to claim 1, wherein the correction coil is wound around a surrounding portion of the core, and the second core is disposed adjacent to the first core. Machine. The electron beam processing machine according to any one of claims 1 to 3, wherein the beam current detection means is provided above the installation portion of the electron gun in the housing. The electron beam processing machine according to any one of claims 1 to 3, wherein the beam current detecting means is provided between the electron gun and the workpiece in the housing. . 3. The electron beam processing according to claim 2, wherein the beam current detection means includes a filter that excludes the frequency of the sine wave generator between the beam current detection coil and the integrator. Machine. The beam current detection means includes means for turning off the sine wave generator and the calculation circuit when the electron beam is generated, and the sine wave is interposed between the beam current detection coil and the integrator. 3. The electron beam processing machine according to claim 2, wherein a filter excluding the frequency of the generator is not installed. The electron beam processing machine according to any one of claims 1 to 7, wherein the core is a ring-shaped ferrite core.

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