JP2006315024A - Surface modification device by electronic beam irradiation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain the target irradiation effect by providing a means to designate the caloric value to be absorbed from the surface as the irradiation condition command, and to measure the caloric value, comparing the measured calorie with the commanded value, feeding back the error of the calorie, and correcting the other irradiation condition. <P>SOLUTION: A measurement body 21 is installed on a table 14 separately from an object 12 to be surface-reformed, the temperature rise is transmitted to a command control device 22 by a sensor provided on the measurement body 21 by allowing the measurement body 21 to receive the same electronic beam irradiation as that of the object 12, and the difference between the measured calorie and the commanded value is fed back to correct the other irradiation condition. A material of the measurement body 21 is the same as that of the object 12. The other irradiation condition includes the cathode voltage, the distance between a cathode and a target, and the pressure of ionized gas for plasma. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  In the present invention, the surface of various metal parts, molds, tools, electrical connection parts, metal medical equipment, metal ornaments, etc. is irradiated with an electron beam in order to make the surface mirror-like, clean, amorphous, and corrosion resistant. The present invention relates to an apparatus for performing surface modification.

This technique is to modify the surface using an electron beam with a cross-sectional area of 10 cm ² or more, a low energy of 10 to 50 KV, and a high current of 10 to 30 KA. Since a low energy electron beam that passes through the gas plasma is used, it does not work deeply when irradiated with a substance, and it has a uniform action over a wide area and is used for surface modification. The modification here refers to removal and purification of foreign substances adhering to the surface of the material, improvement of surface roughness, flattening of microscopic unevenness to form a mirror surface, amorphization of metal by rapid heating and cooling, and corrosion resistance Etc.

  This technique is a kind of electron gun, but it is also called a plasma electron gun because it is not a vacuum chamber but is filled with low-pressure ionized gas and turned into plasma. In order to keep this plasma stable, an annular plasma anode called a reflected discharge system is provided, and a solenoid is provided outside the electron gun to create a magnetic field in the space inside the gun.

  In the electron beam emission mechanism of this apparatus, a disk-like metal or graphite is used as a field emission cathode, and the irradiated object becomes a target anode. A high-voltage capacitor discharge of 10 to 40 KV is generated between both electrodes to emit an electron beam pulse of about μs. The plasma generation circuit generates glow discharge by charging / discharging the capacitor between the annular anode and the electron gun casing to turn the ionized gas into plasma. The plasma holding time is several hundreds μs, and the electron beam emission is performed within that time. Another capacitor charging / discharging circuit is provided as a power source for exciting the solenoid for creating a magnetic field in the electron gun before and after the plasma holding time.

  Place the irradiated object with surface modification on the table as a target, evacuate the inside of the electron gun, fill it with ionized gas, for example Ar gas, and form magnetic field, plasma, and electron beam When activated, the surface of the irradiated object is modified. Usually, one irradiation is insufficient, and after several to several tens of irradiations, the electron gun is opened and the irradiated object is taken out.

  Although it is necessary to select the irradiation conditions depending on the material of the irradiated object, the composition of the components, the surface area, the state before modification, etc., there are no formulas for selecting the conditions, so it depends on the results of experiments and experience. As a common judgment, a material having a high melting temperature is irradiated with a large energy, and a material having a low melting temperature is irradiated with a small energy. It should be noted that the energy referred to here is not the amount of heat received by the irradiated object by the radiated energy. In this specification, the radiant energy and the amount of received heat are described separately. The conditions for changing the radiant energy are usually 1) cathode voltage, 2) distance between cathode and target, and 3) ionized gas pressure. These conditions can be adjusted by command means of a system that controls and operates the entire apparatus.

  FIG. 9 is an overall configuration diagram, 1 is a housing, 6 is an annular electrode, 8 is a cathode, S is an electron gun space, 5 is an excitation solenoid, and 14 is a table as a target. A table moving mechanism or the like (not shown) is provided at a portion below the one-dot broken line portion 1-1. A scroll pump 2 and a turbo molecular pump 3 are connected via flow rate adjusting valves 2A and 3A as an adjustment system for ionized gas in the electron gun, and further operate together with a pressure sensor (not shown). The chamber is once evacuated and then filled with a rare gas such as Ar from the cylinder 15 and maintained at a predetermined pressure.

  The reformer is first operated to generate an excitation power source 16 that generates a magnetic field by a solenoid 5 in the electron gun chamber, and then operates to operate a pulse power source 17 including a capacitor charge / discharge circuit that generates plasma near the annular anode, and plasma. There is provided a pulse power source 18 which is a power source for performing reforming by radiating a passing electron beam and configured by a capacitor charging / discharging circuit. Each power source is independent and insulated from the housing 1 by insulators 6A and 8A.

Japanese Patent Application Laid-Open No. 09-216075 JP 2003-111778 A JP 2004-1086 A Yoshiyuki Uno, 4 others "Die finishing and surface modification by large area pulsed electron beam" Electromachining Technology, Japan Society for Electrical Machining, June 2003, No. 27, No. 86, p. 12-17, Tomoyasu Kajishita and 4 others "Study on Finishing of Die Machining by Large Area Electron Beam (2nd Report)" Smoothing Characteristics and Surface Modification Effect of Inclined Surfaces-Proceedings of National Conference on Electrical Machining (2003) Japan Institute of Electrical Machining, 2003 February, p. 47-50, Outside G.E.OZUR 3, Production and application of low-energy, high-current electron beams, Laser and Particle Beams (2003), 21,157-174, Printed in the USA.

  The purpose of surface modification is various, such as improvement of surface roughness, mirror surface, cleaning, amorphization, corrosion resistance, and various materials. Therefore, it is difficult to properly select the above three conditions. Since the proportion of the emitted electron beam is dissipated and absorbed by the irradiated object is not constant, the resulting effect also has a drawback. This is because it was not possible to have data on conditions that would result in the same irradiation result as the irradiated object.

  As described in the prior art, this device has the ability to give excellent results for various purposes, but in order to use it properly, it is necessary to select irradiation conditions appropriately according to various materials and conditions before processing. is there. The amount of heat received by the irradiated object is closely related to the modification result, and the excess or deficiency affects the irradiation effect. Therefore, if the irradiation condition can be adjusted via the amount of heat, the object can be easily achieved.

  When the electron beam of this device hits the surface of the target, a considerable amount of light is emitted, secondary electrons, electromagnetic radiation, X-rays and metal vapors are scattered, and the remainder is absorbed by the irradiated object and dissolved in the absorption process. And surface modification is performed together with evaporation. Since the electron beam enters through the network of the crystal lattice and moves as free electrons or grain boundary movement, the absorptance varies depending on the material and composition.

  The increase in the amount of heat of the irradiated object is the beam energy related to the reforming mechanism, but there is an evaporation mode and a dissolution mode, and the former is not included in the increase in the amount of heat. In addition, there is a complexity that the heat quantity ratio in both modes differs depending on the irradiation conditions.

The amount of heat remaining in the irradiated object is closer to the fact than the calculated value of the energy of the emitted electron beam, and the correlation with irradiation effects such as surface roughness and melting depth is reliable. In addition, as described in the irradiation condition of paragraph [0006] above, the electron beam energy can be selected from three irradiation conditions. For example, when the cathode voltage is changed from A to B, the same energy condition can be obtained. The distance between the cathode and the target can be determined immediately by mediating calorimetric data. In this specification, the amount of heat (J / cm ² ) received by the irradiated object is referred to as irradiation energy.

  The difference in heat absorption due to the type, composition, and crystal state of the irradiated metal is not only due to dissipation due to light emission and reflection, but also due to differences in metal evaporation from the surface and electron beam movement inside the metal. 13 This is the reason why the material of the calorimeter is required to be the same quality as the irradiated body.

  The emission energy of the electron beam of the apparatus exemplified in this specification is configured so that it can be changed and set according to the cathode voltage of the pulse power supply 18 and the concentration of ionized gas. When the electron beam 11 in flight is affected by plasma, the concentration of the ionized gas, that is, when the pressure is changed, the intensity of the electron beam incident on the irradiated object changes even when the same cathode voltage is used.

An example of this experimental result is shown in FIG. The ionized gas pressure (horizontal axis) and the amount of heat received per surface area (vertical axis) were tested for three types of cathode voltages. This shows that the calorific value received by the irradiated object is influenced by the ionized gas concentration. However, this correlation is limited to a specific range, and it is necessary to select an optimum value of the ionized gas concentration. This experiment and the experiment described below are values obtained by attaching a temperature sensor to an object to be irradiated made of copper, measuring a temperature rise for each irradiation, calculating an increased heat value, and dividing by a surface area. In the present specification, this received heat amount value per surface area is hereinafter referred to as irradiation heat amount (J / cm ² ).

Another experiment is shown in FIG. 11, in which the relationship between the cathode voltage (KV) and the amount of irradiation heat (J / cm ² ) was tested for the distance between the two types of cathodes and the target. This relationship has continuity within the experimental range and high practicality, but continuous fine adjustment is difficult by handling a high voltage.

  Another experiment is shown in FIG. 12, which is the result of examining the relationship between the distance from the cathode to the irradiated object and the amount of irradiation heat for two types of cathode voltages. This relationship is also continuity within the experimental range, and since changing the distance is easy to implement, it is optimal for changing the reforming conditions.

The state of the prior art and various experimental results have been described above, and the mechanism of electron beam surface modification has been considered. The points to be improved based on this are summarized as follows and are the object of the present invention.
A calorimeter measuring system including a calorimeter is added to the electron beam irradiation surface reforming apparatus, and the calorimeter is placed on a table so that it can be irradiated with an electron beam under the same conditions as the object to be irradiated. The cathode voltage, the distance between the cathode and the object to be irradiated, and the ionized gas pressure are set as the irradiation conditions, and the heat increase value and allowable range to be commanded are input and stored in the control device, and the heat amount of the measurement result and the command heat amount are compared. The error is fed back to the condition adjusting means, and the irradiation condition is adjusted to be within an allowable range. The material of the measurement body is the same as or similar to the material to be irradiated.

  The object of the present invention described above includes (1) a cathode 8, a plasma generation electrode 6, a housing 1 filled with an ionized gas, and a table 14 on which an irradiated body 12 that receives an electron beam from the cathode is installed. An electron gun device comprising a solenoid 5 for forming a magnetic field in the housing, generating plasma after the solenoid forms a magnetic field, and further applying a pulse voltage between the cathode and the irradiated object to generate plasma In the apparatus for performing the surface treatment of the irradiated object by emitting an electron beam pulse having a path as a path, the apparatus includes means for adjusting the cathode pulse voltage, the distance between the cathode and the irradiated object, and the ionized gas concentration as irradiation conditions, A program control device that inputs irradiation conditions of the electron beam pulse and advances irradiation condition commands, execution, and control, and the same posture as the irradiated object Depending on the calorie measuring body installed in the table, the sensor for measuring the temperature rise of the measuring body, and the irradiation condition according to the command calorific value input to the program control device, or simultaneously with the irradiation to the irradiated body, or A calorific value measuring device is provided that reads a temperature rise as a result of irradiating the measuring body in a separate process with the sensor, calculates a calorific value, and transmits an error to the program control device in comparison with a command calorific value, This is achieved by providing a surface modification device in which the program control device feeds back the error through the condition adjusting means and adjusts the error to fall within an allowable value.

  The object of the present invention is achieved by (2) the surface reforming apparatus according to (1) above, wherein the calorimeter is made of the same material as the irradiated body.

Further, the object of the present invention described above is (3) means for adjusting the irradiation conditions so that the measured calorific value coincides with the command calorific value,
Means for increasing or decreasing the distance between the cathode and the irradiated object;
Means for changing the concentration of ionized gas filled in the electron gun,
Or pulse voltage changing means applied to the cathode,
It is achieved by using the surface modifying apparatus according to (1) or (2), which is any one of the above.

  The above-mentioned object of the present invention is as follows: (4) As a means for changing the electron beam irradiation distance between the cathode and the table, the advance / retreat mechanism for moving the table along the electron beam axis with respect to the cathode fixed to the housing. The surface modification according to (1) or (3), wherein the table is provided with either or both of an advancing / retreating mechanism in which the cathode does not move along the axis but moves along the axis. This is achieved by using a device.

  Further, the object of the present invention is as follows: (5) An object to be irradiated and a calorimeter are separately installed on a table orthogonal to the electron beam axis, and the electron beam pulse is irradiated to the calorimeter first. Then, after performing the calorimetric measurement, comparison and adjustment cycle and determining the irradiation conditions in which the measured calorific value is within the allowable range, the position of the calorimeter and the irradiated object is exchanged, and the modification processing is performed according to the irradiation conditions. This is achieved by a surface modification method using the apparatus according to (1) above, which is started.

According to the above-mentioned invention (1) of the present invention, as a result of the surface modification, the irradiation heat amount (J / cm ² ) is given as a command value, the irradiation heat amount is measured by a calorimeter measurement set, the heat amount increase value and the command irradiation heat amount. The difference from the value can be fed back to the irradiation condition adjusting means to adjust the irradiation condition to reach a desired amount of irradiation heat (J / cm ² ).

  In addition, according to the present invention (2), since the amount of irradiation heat is measured with the irradiated body, the measurement is quite accurate, and the treatment effect of the surface modification processing is the material of the measuring body and the irradiated body. Differences due to the difference can be avoided, and the amount of heat obtained by the irradiated object by adjusting the irradiation conditions is the same as the commanded amount of heat, so that the quality of the reforming operation is guaranteed.

In the present invention, the received heat amount (J / cm ² ) of the irradiated body is set as a target value, the distance between the cathode and the irradiated body (cm), the ionized gas concentration (Pa), and the voltage (KV) applied to the cathode as the manipulated variable. However, the three operational sensitivities and the controllable range (J / cm ² ) are different. From FIG. 10, FIG. 11, and FIG. 12, it can be seen that there are inoperable areas due to device design reasons, the characteristics of the electron beam emission mechanism itself, restrictions on use, and the like. According to the present invention (3), the operation means of the feedback control can be selected from the three types, and can be selected, combined and connected in time series to achieve the object.

  According to the present invention (4), three types of design formats can be selected as means for changing the distance between the cathode and the irradiated object. The first type is a type in which the table moves forward and backward along the electron beam axis with respect to the cathode fixed to the housing. If the device is regarded as an electron gun, the distance from the muzzle to the target is variable. The second type is a type in which the cathode advances and retreats toward a table that does not move along the axis with respect to the housing. The length of the barrel of the electron gun is variable, and the distance between the muzzle and the target does not change. In any of the above types, the distance between the cathode and the target is changed, but the relationship between the distance and the reforming effect is not equal. The third type design format is a format having both the first type and the second type, and the design type can be selected and used. Which format is selected is determined by the advantages and disadvantages of design and manufacture, convenience and advantages and disadvantages in use.

  Further, according to the present invention (5), the irradiated object and the calorimeter are separately installed on the table, and the irradiation condition is determined by performing irradiation and measurement on the calorimeter first. Then, the method of starting the irradiation of the irradiated object can be taken to improve the efficiency of the modification work.

FIG. 1 is an explanatory front sectional view of an apparatus according to an embodiment of the present invention, which corresponds to the apparatus of FIG. 11 of the above-mentioned conventional example, and the same or equivalent parts are indicated by the same reference numerals. .
The table 14 is installed on the horizontal biaxial moving device 19 and positioned at the command value. From the electron gun unit 1A, the calorific value measurement set 21, which will be described later, and the irradiated object 12 are moved from the electron gun unit 1A at the same time or in different steps, if necessary, under substantially the same conditions and posture, depending on the biaxial movement and mutual installation interval. The electron beam pulse 11 is set on the table 14 so that it can be irradiated.

  The horizontal biaxial moving device 19 is composed of a fixed base 19A and an XY guide set 19B, and is commanded up and down and positioned by vertical moving mechanisms 20A and 20B. An XY guide set 19B provided in the fixed base 19 is used for positioning the table 14 by horizontally moving in two axes in the XY directions in accordance with an XY axis movement positioning command from the commanding device 22E. The linear guide, ball screw, servo motor, Various known configurations using elements such as a linear motor are possible.

The vertical movement mechanism is composed of a Z-axis rack column 20A and a pinion mechanism 20B. The horizontal biaxial moving device 19 is fixed to the head of the Z-axis rack column 20A, and the rack is carved at the lower part to mesh with the pinion mechanism 20B. There is a drive device for the pinion mechanism 20B (not shown), and the pinion is rotated by the Z-axis movement positioning command of the commanding device 22E, and the Z-axis rack column 20A is moved up and down in the Z-axis direction so that the surface of the irradiated object 12 is moved to the irradiation distance h. Position. In this embodiment, since the vertical movement mechanism is outside, the moving part has an airtight structure, and the table 14 is connected to the processing box 1B by a ground wire 26.
In addition, the structure of the up-and-down advance / retreat mechanism is not restricted to this embodiment, and a known mechanism can be freely selected other than, for example, a ball screw instead of a rack and a pinion.

  FIG. 2 is a perspective view showing the calorie measurement set 21 installed on the table 14. The calorie measurement set 21 includes a measurement body 21A, a contact-type temperature sensor 21B such as a thermocouple, the measurement body 21A, and an installation base. 21C and a column 21D having a small thermal conductivity that is separated from the table 14, is thermally insulated, and is installed at the electron beam irradiation position. The temperature sensor 21B can be configured for the same purpose instead of a radiation thermometer.

FIG. 3 is a cross-sectional view of an embodiment of the one column 21D. The column 21D is a nonmetal having a low thermal conductivity, usually an oxide ceramic such as Al ₂ O ₃ or _{ZrO 2} , or SiC. It is preferable to use non-oxide ceramics such as Si ₃ N ₄ or the like, and a conductor 21E for grounding the measurement body 21A to the table 14 through the base 21C as a hollow columnar body is inserted into the hollow portion, and the upper and lower ends thereof are It is connected to a metal piece 21F that is in contact with the measurement body 21A and the base 21C.

  As a material of the measurement body 21A of the calorie measurement set 21, a material of the same material as the irradiated body 12, such as a mold, which is subjected to surface modification processing should be selected and set. This is because the effect (absorption heat amount) of the surface modification processing by this process has a significant difference depending on the material components of the irradiated object, as shown in the table of FIG. Furthermore, it should be noted that the characteristic relationships of FIGS. 10, 11 and 12 described above also vary depending on the material and the material of the measurement body.

  The entire upper surface 21G of the measurement body 21A has a predetermined area (A) on the surface to which the electron beam 11 is irradiated. In the illustrated embodiment, the frustum is formed upside down in order to accurately limit the irradiation area. Is done.

As will be described later, the irradiated body 21A has known mass (M), specific gravity (ρ), volume (Q), specific heat (Cp), surface area (cm ² ), and the like as specified values necessary for calculating the amount of irradiation heat. Further, since the distance between the irradiation surface 21G of the measurement body 21A and the lower surface of the cathode 8 needs to be equal to the distance (h) between the irradiation object 12 and the cathode 8, the support leg 21D can be freely replaced.

  In FIG. 1, reference numeral 22 denotes a CNC control device, which is an input device 22A, a program control device 22B, a calculation device 22C, a display device 22D, and a control command output device 22E to an axis moving device 23 such as an outer XYZ or various functional devices 24. The program control device 22B instructs the calorimeter 25 to read the difference between the temperature before the irradiation to the measuring body 21A and the equilibrium temperature after the irradiation. From the temperature difference and the irradiation area (A), specific heat (Cp), and mass (M) of the measuring body 21A, the result calculated by the irradiation heat amount calculation program set in the calculation device 22C is discriminated. Performs heat feedback control.

  When a command signal is output from the control command output device 22E to the function drive device 24, the function drive device 24 drives the pinion gear 20B according to the content of the command to set the irradiation distance (h) or the third pulse power supply 18. The voltage regulator 18A is operated to adjust the cathode voltage (KV), or the adjusting valve 4 and the switching valve 3A are operated to adjust the inflow and discharge of the rare gas, thereby adjusting the gas pressure (Pa ) Are adjusted individually or in appropriate combination.

In this apparatus, the calorific value measurement set is provided in order to measure the calorific value received by the irradiated object.
FIG. 4 shows a temperature course from when the surface of the calorimeter 21A is irradiated until it reaches equilibrium.
The energy received at a known surface area (Acm ² ) is irradiated at the time (to) and instantaneously raises the surface temperature, but the heat diffuses rapidly and lowers the surface temperature, while the bottom surface temperature and Increase the midpoint temperature. Equilibrium at time (tx) makes the entire temperature uniform. Therefore, the amount of received heat (J / cm ² ) per area is calculated from the difference (ΔT) between the temperature at time (to) and the temperature at time (tx).

Further, in this apparatus, irradiation is performed several times according to the flowchart of FIG. FIG. 5 shows the transition of the surface temperature of the measuring body 21A in the course of the process. FIG. 5 is a continuation of FIG. 4 of [0041], and the time (tx-to) in FIG. 4 becomes the measurement time (tm) in FIG. It corresponds. The temperature difference (ΔT) obtained in FIG. 5 is sent to the program device, and the received heat amount per area (A), the specific heat (Cp), and the mass (M) of the measurement body 21A input in advance ( J / cm ² ) is calculated, displayed on the display device 22D, subjected to discrimination processing, and the process proceeds.

  In FIG. 5, (tm) should change according to the temperature difference (ΔT) to be precise, but it can be ignored in practical use, and the natural temperature after the measurement body 12A reaches the equilibrium temperature. In practice, the temperature drop due to heat dissipation is negligible.

In FIG. 5, each irradiation condition from the first irradiation to the fourth irradiation is determined by comparing the measured calorific value (J / cm ² ) with the command value as shown in the flowchart below, and the program device follows the algorithm. Thus, the difference is fed back to each irradiation condition adjusting mechanism to approach the commanded calorific value, or the execution of irradiation is started under the condition of a predetermined error range.

In the present invention, the amount of heat received per unit area of the irradiated object (J / cm ² ) is regarded as irradiation energy, and the amount of heat most closely related to the surface modification effect is used as an index, so that the reliability of the apparatus can be improved. Ensuring stability and stability. As a specific example, when the cathode voltage is unstable, it is difficult to know the extent afterwards, and the same is true even if the plasma is unstable. Even in such a case, the result of calorimetry immediately indicates the instability as a numerical value. Moreover, even if the apparatus remains unstable, it is possible to achieve the object by correcting the conditions up to the command heat amount.

  The first embodiment of the technique for adjusting the irradiation condition of the electron beam so that the measured calorific value becomes the set commanded calorific value by measuring the calorific value is shown in FIG. 12 as a characteristic of the relationship between the irradiation distance and the calorific value. 6 is a change in the distance (h) between the end face of the cathode 8 shown in the figure and the surface of the irradiated body 12, and the amount of irradiation heat and the irradiation distance are in an inversely proportional relationship. A case where the irradiation condition is adjusted by the method of the flowchart will be described.

This invention proposes a method of instructing the reforming condition by the calorific value received by the irradiated object. As an effect, the reforming conditions are not artificially determined, but are experimentally performed as a result of measurement of heat quantity. Since there are three types of conditions governing the reforming result as described above, there are three types of methods. FIG. 6 is a flowchart showing a process for a method of changing the irradiation distance, which is one of them, to a variable value. . Explaining this in accordance with the promise, (1) is a flow line that gives the memory 2 a fixed command necessary for driving the device. The command heat quantity C, various constants necessary for discrimination, and other conditions that are not variable (this In this case, the cathode voltage and the concentration of the low-pressure gas are fixedly recorded and cannot be rewritten. The line (2) is for placing the measured heat quantity in the temporary recording memory 1 and passing it to the comparison calculation unit. The result of the comparison operation unit is divided into three parts as shown in the figure, and if the condition is deviated, the retry is repeated, and when the condition is reached, the regular reforming operation is started. Needless to say, the storage, calculation, and determination of this flowchart are performed inside the control device 22.
Although FIG. 6 describes the above three types of methods, the part relating to calorimetry and the logic of discrimination are the same, and the means for changing the governing conditions have already been described, so FIG. 6 is replaced with the other two types of methods. It is also adopted in the explanation of.

  As described above, the measurement of the amount of irradiation heat is performed by measuring the temperature difference between the equilibrium temperature before and after the irradiation of the electron beam pulse of the measuring object, and measuring and inputting the temperature difference and the measuring object in advance. A measured value of the irradiation heat amount W is obtained using the irradiation area of the electron beam, specific heat, mass, calculation formula, and the like, and is stored in the memory 1. When the irradiation heat quantity W is measured, a comparison calculation (| W−C | −E) = Δ with the command heat quantity C is performed, and whether or not the deviation of the measurement heat quantity W from the command heat quantity C is within the set allowable error E. Is determined. In the above determination, if the allowable error E is within the input set value, the process proceeds to the electron beam pulse irradiation step (4) of the surface modification processing step, and the surface modification that has been set as described above. When the number of times of irradiation is performed and the number of times of irradiation reaches a predetermined set number of times, the surface modification processing on the irradiated object is finished.

  Incidentally, the deviation of the measured heat quantity W with respect to the command heat quantity C may be smaller than the allowable error E, contrary to the case where the deviation is larger than the input allowable error E. First, in the former case, the deviation (C−W) is reduced. A value multiplied by the constant α is taken into the program control device 22B as data, and the pinion gear 20B is connected to the Z-axis of the shaft movement drive device 23 via the command output device 22E, and the Z-axis rack column 20A is moved a predetermined distance in the Z-axis direction. Then, the position is rotated and positioned so that the irradiation distance h increases, and a positioning completion signal is transmitted to the program control device 22B via the function driving device 24, and the new irradiation adjusted and set by returning to the heat quantity measurement step (3). Measure the heat of irradiation at a distance.

  When the latter deviation is much larger than the allowable error and the irradiation heat quantity is much smaller, the program control device 22B takes in the deviation (WC) multiplied by a constant β, Contrary to the case, the pinion gear is rotationally positioned so as to increase a predetermined distance in the Z-axis direction and decrease the irradiation distance h, and operates to adjust and set a new irradiation distance.

  Then, if the measured heat quantity at the new irradiation distance is corrected and adjusted within the deviation of the allowable error E or less with respect to the command heat quantity, the process proceeds to the electron beam pulse irradiation process of the surface modification process described above. If this is not the case, the irradiation distance change adjustment by measuring the irradiation heat quantity is repeated until the deviation falls within the allowable error E.

  In the second method of the present invention, a capacitor is charged from the third pulse power source 18 between the cathode 8 and the irradiated body 12 shown as the characteristic graph of the cathode voltage and the amount of heat in FIG. As in the case of the first method, the received heat quantity measured from the irradiation under the irradiation condition set in accordance with the command irradiation heat quantity becomes the target command heat quantity. The voltage regulator 18A of the pulse power supply 18 including the capacitor charge / discharge circuit is switched and adjusted from the program control device 22B to the function driving device 24 via the command output device 22 by the algorithm of the flowchart until the value of the cathode voltage ( KV) changes and adjusts the electrical specifications.

  FIG. 8 shows a basic circuit configuration of a pulse power source 18 for applying a negative high voltage pulse for accelerating the generation of the electron beam 11 between the cathode 8 and the irradiated object 12 and its voltage regulator 18A. The charging voltage of the capacitor 18C is rectified and charged to a predetermined voltage from the AC power supply AC through the high voltage conversion transformer 18B having the voltage regulator 18A and through the diodes 18D1 and 18D2. Then, the signal 18S that the charging voltage of the capacitor 18C has reached a predetermined value, the gas concentration signal 29a that the gas pressure sensor 29 detects that the gas pressure in the housing has reached a predetermined set pressure, and the pulse power source 17 When the three conditions of the signal 18F that conveys that a plasma is generated by applying a pulse voltage between the plasma generation electrode 6 and the target 14 are matched, the gate of the thyristor SCR is triggered from the signal generator 18E, and the capacitor 18C The charged charge is discharged between the cathode 8 and the irradiated object 12 to generate an electron beam pulse 11. The thyristor SCR may be replaced with other trigger switch elements such as a gas-filled trigger discharge switch.

The third method of the present invention intends to use the relationship between the amount of heat generated by the generated electron beam irradiation and the Ar gas pressure (Pa) in the vacuum housing 1 forming the electron beam generating region. As shown in the characteristic diagram of the relationship between the heat quantity (J / cm ² ) and the gas pressure (Pa) in one embodiment in FIG. 10, the correlation between the two is the irradiation distance (h) of the method 1 described above. Although it is not as obvious as the acceleration voltage (KV) of method 2 or the like, the gas pressure change can be used as a means for changing the irradiation heat quantity in a part of the gas pressure (approximately 0.05 to 0.09 Pa) region to be used. It turns out that there is a possibility.

As a specific method, a cathode voltage, plasma conditions, and irradiation distance are input as fixed conditions from an input device 22A of the CNC control device 22 using an Ar gas as an ionizing gas for generating plasma (FIG. 1). At the same time, assuming the amount of received heat that seems to be optimal for surface modification, the target value is input as the irradiation heat amount value (C). At the same time, the allowable range value (E) for the target value is also given as a constant. If the rise command in FIG. 6 of the measurement sequence is replaced with a pressure drop command and the machining command is replaced with a pressure rise command, the values of α and β are also determined accordingly, and the values are input together with the value of (E).
In this case, since the target heat quantity is a gas pressure variable condition, an appropriate value in the pressure region is input as an initial command value, and a measurement cycle is started. Each above-mentioned command value is sent to each functional device via control device 22B and command output device 22E, and a measurement irradiation cycle is started. The Ar gas concentration is determined by first opening the flow control valve 4 of the Ar cylinder 15 slightly while the housing 1 is evacuated by the scroll pump 2 and the turbo pump 3, and Ar gradually flows into the housing to increase the concentration. . During this time, the gas pressure sensor 29 continues to send the concentration signal 29a to the function driving device 24. When the signal 29a continues for several seconds and indicates the initial command value, the gas pressure sensor 29 determines that the state is stable and activates the circuit for applying the cathode voltage.
When the first irradiation is completed, the calorific value is measured, and the result of determination is made by the calculation device 22C. If the value deviates from the allowable range, the initial value is corrected and the next measurement cycle is started. A cycle takes 10-20 seconds. Thus, when the allowable amount of irradiation heat is obtained, the reforming process is repeated as many times as the number of commands with the gas pressure as the command value.

  From among the first, second, and third methods described above, a preferable method is selected, or an object to be adjusted is determined according to the magnitude of the commanded calorific value, and further depending on the properties of the irradiated object. There may be a plurality of adjustment targets at the same time, or a plurality of adjustment targets in time series.

  FIG. 7 is a front sectional view of another specific embodiment apparatus according to the first method, which also serves as a table that can be moved and positioned on the Z axis in the irradiation axis direction in the embodiment of FIG. The field emission cathode 8 instead of the target 14 is configured to be movable and positioned on the Z axis of the irradiation axis together with the holder 30 and is attached to the electron gun unit 1A so that the irradiation distance (h) can be changed to be longer or shorter. Is.

  That is, in the drawing, the cathode 8 is inserted into the electron gun unit 1A so as to be slidable through an insulating bush 31 made of plastic or ceramics so as to be movable in parallel with the Z axis of the irradiation axis. The cylindrical holder 30 is coaxially fixed by a holder 8C, and the fitting and sliding portion is vacuum-sealed. The bracket 40 provided on the fixed-side electron gun section 1A is connected with a feed screw 33 and is attached with a feed motor 32 that is driven by a command from the control device 22. The holder 30 is moved by screwing the screw 33 into the nut 34 attached to the bracket 35 provided in the section.

  The embodiment of FIG. 7 is the same as that of the embodiment shown in FIG. 1 in that the irradiation distance (h) of the electron beam 11 between the field emission cathode 8 and the target 14 is changed. The changing action and effect are different. The reason is the difference between the case where the beam emission mechanism in the electron gun is changed as described in [0029] and the case where the distance from the muzzle to the target is changed. The former has many related factors and is complicated in use, but has the advantage that a table lifting mechanism is unnecessary.

  The present invention can use the surface modification work in the electron beam pulse irradiation modification processing apparatus by accurately adjusting and setting the irradiation heat quantity according to the irradiation conditions selected and set.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. The perspective view of the part of an Example apparatus. Sectional drawing of the part of FIG. FIG. 4 is a characteristic diagram of heat conduction for explaining the present invention. The characteristic view of the temperature change at the time of operation | movement of this invention apparatus. The flowchart figure explaining the Example of the 1st method of this invention. FIG. 6 is a front sectional view of another specific example apparatus according to the first technique of the present invention. The fundamental circuit block diagram of the Example which concerns on the 2nd method of this invention. The apparatus sectional view showing the whole composition of the conventional apparatus. The characteristic diagram of discharge gas pressure, the energy density of an electron beam, and an acceleration voltage. The characteristic diagram of acceleration voltage and energy density. The characteristic diagram of the irradiation distance of an electron beam, energy density, and acceleration voltage. The table | surface which shows that there is a difference in the amount of absorbed heat of an irradiation electron beam by the material of a measurement body.

Explanation of symbols

1 Housing 1A Electron Gun 1B Box 2 Scroll Pump 3 Turbo Molecular Pump 4 Flow Control Valve 5 Solenoid 6 Anode Plasma Generation Electrode 7 Anode Plasma 8 Field Emission Cathode 9 Cathode Plasma 11 Electron Beam Pulse 12 Object to be Irradiated (Work)
14 Table 15 Ionizing gas 16 Solenoid excitation pulse power supply 17 Anode plasma pulse power supply 18 Acceleration voltage cathode pulse power supply 19 Horizontal biaxial moving device 20A Z-axis rack post 20B Pinion gear 21 Calorie measurement set 21A Measurement body 21B Temperature sensor 21C Installation Base 21D Non-metallic strut 21E Conductor 21F Metal piece 21G Irradiated surface 22 CNC control device 22A Input device 22B Program control device 22C Calculation device 22D Display device 22E Command output device 23 Axis movement drive device 24 Function drive device 25 Calorimeter 26 Grounding Conductor 29 Gas pressure sensor 29a Gas concentration signal

Claims (5)

  A solenoid 5 that includes a cathode 8, a plasma generation electrode 6, a housing 1 filled with an ionized gas, and a table 14 on which an irradiated body 12 that receives an electron beam from the cathode is installed, and forms a magnetic field in the housing. An electron gun device comprising: a plasma generated after the solenoid forms a magnetic field; and a pulse voltage is applied between the cathode and the irradiated object to emit an electron beam pulse using the plasma as a passage. In the apparatus for performing the surface treatment of the irradiated object, the cathode pulse voltage, the distance between the cathode and the irradiated object, and means for adjusting the ionized gas concentration as the irradiation condition, the irradiation condition of the electron beam pulse is input, Program control device for advancing irradiation condition commands, execution, and control, and calorimetry installed on the table in the same posture as the irradiated object And a sensor for measuring the temperature rise of the measurement object, and the irradiation condition according to the command heat value input to the program control device, the measurement object is irradiated simultaneously with the irradiation of the irradiated object or in a separate process. A calorific value measuring device is provided for reading the temperature rise as a result of the calculation by the sensor, calculating the calorific value, and comparing the command calorific value with the command calorific value, and transmitting the error to the program control device. The surface modification device is characterized in that the error is fed back and adjusted so as to be within an allowable value.   The surface modification apparatus according to claim 1, wherein the calorimeter is made of the same material as the irradiated body. Means for adjusting the irradiation conditions so that the measured calorific value matches the commanded calorific value,
Means for increasing or decreasing the distance between the cathode and the irradiated object;
Means for changing the concentration of ionized gas filled in the electron gun,
Or pulse voltage changing means applied to the cathode,
The surface modification apparatus according to claim 1, wherein the surface modification apparatus is any one of the above.   As a means for increasing or decreasing the electron beam irradiation distance between the cathode and the table, an advance / retreat mechanism in which the table moves along the electron beam axis with respect to the cathode fixed to the housing, and the table does not move along the axis. 4. The surface reforming apparatus according to claim 1, wherein one or both of an advancing / retreating mechanism in which the cathode moves along the axis is provided. 5.   The object to be irradiated and the calorimeter are placed separately on a table orthogonal to the electron beam axis, and the electron beam pulse is irradiated, calorimetrically, compared, and adjusted on the calorimeter, and then measured. 2. The reforming process according to claim 1, wherein after determining the irradiation condition in which the amount of heat falls within an allowable range, the position of the calorimeter and the object to be irradiated is exchanged to start the reforming process according to the irradiation condition. Surface modification method using the apparatus of.

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