JPS6234715B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to oxides, nitrides, carbides, borides,
Single-phase ceramics mainly composed of one type of ceramic compound such as silicide, fluoride, sulfide, phosphide, arsenide, selenide, or telluride, or two or two types of the above ceramics. Composite ceramics consisting of the above compounds, or natural or artificial powdered compounds such as oxides, carbides, or boride-based cermets, which are made by adding metals to ceramics, are molded and fired at high temperatures. The present invention relates to a method for processing so-called ceramics, which are polycrystalline solid materials made of inorganic compounds of elements. Except for special ceramics, these types of ceramics generally have a higher melting point than metals, have a higher free energy of formation (bonding energy), and are extremely chemically stable, as shown in the table below. It is.

[Table] Also, because of its high hardness, in order to process it mechanically, it is necessary to use cutting tools, drills, or grinding wheels that have cutting chips or abrasive grains such as diamond or cBN (cubic boron nitride) as cutting edges. The cutting or grinding ability is significantly lower than that of metals and alloys, and it is brittle and easily cracked, making it unsuitable for processing and forming by mechanical cutting or grinding. and reduced the range of applications. In addition, such ceramics are generally referred to as insulators, and their electrical conductivity is significantly lower than that of metals and alloys, and their thermal conductivity is also extremely low, so they cannot be cut with diamond chips or abrasive grains. The energy required for grinding is transmitted to the tool side that has the chips or abrasive grains, and therefore the wear and damage on the tool side can be significantly greater than in the case of cutting or grinding metals and alloys. Not a few. As described above, ceramics have a high melting point, high hardness, but break easily, low electrical conductivity, and are chemically stable, making them extremely difficult to process using conventional processing methods. However, the present invention aims to overcome such difficulty in machining, and uses conventional mechanical cutting or grinding, electrical machining such as electrolysis or discharge, laser or Rather than simple processing in which each processing method such as energy beam processing such as electron beam processing or various chemical processing is applied individually, two or more processing methods are used as described above based on the characteristics of each processing method. , not only the characteristics, but also the timing of applying two or more processing methods, i.e., for example, the timing of applying two or more processing methods to the same part of the workpiece, almost simultaneously or immediately after the application of one processing method to the other processing. Composite processing in which one processing method is applied while the processing action or effect of one processing method remains, such as applying a processing method or applying two or more processing methods alternately. This method overcomes the difficulties of ceramic processing. Chemically stable metal oxides and other compounds used in ceramics are
Compared to ordinary metals, alloys, etc., they generally have excellent acid and alkali resistance, but this refers to relatively low-temperature areas such as room temperature, such as ordinary living rooms.In high-temperature areas, metals, Its reactivity is as high as that of alloys. That is, as is generally known, ordinary metal oxides have a high frequency range (e.g. approx.
Dissolves in acids (e.g. sulfuric acid) and alkalis (e.g. caustic soda, which are usually strong acids and strong alkalis) at temperatures higher than about 100°C (approximately 100 to 400°C). Therefore, it is possible to locally apply the reaction action of such high-temperature acids and alkalis to the desired processed portion of ceramics, separate it from other surrounding parts, and then remove the processed portion by some means. If possible, it means that the ceramics have been processed, and such processing is not limited to high-temperature acids and alkalis; for example, neutral salt electrolytes such as NaCl that produce acid at the positive electrode and alkali at the negative electrode through electrolysis. Alternatively, chemically active ions, such as halogen gas Cl ^-- , etc. may be applied to the ceramic under predetermined high temperature conditions to decompose the oxide in the relevant portion. Therefore, even if the above-mentioned chemical reaction with high-temperature acids or alkalis is performed on ceramics, there must be containers that can withstand such high-temperature acids and alkalis, and reliable supplies and means for supplying and recovering them. In addition, it was difficult with the prior art to act only on a desired local portion of the ceramic workpiece. Therefore, the present invention solves these difficulties and
This enables processing such as drilling, engraving, cutting, and forming grooves on the ceramic workpiece, by applying an acid or alkaline electrolyte to the surface area of the desired processing area of the ceramic workpiece. The high temperature of the acid or alkaline machining fluid is increased by supplying energy to the local area from the outside to create a high temperature state by spraying, flowing down, dropping, etc., a desired unit amount of the machining fluid dissolved in the Preferably, all or most of the acid or alkali in the supplied machining fluid reacts with the ceramics in this condition, and the deterioration products or residues resulting from this reaction, or the reaction parts weakened by the reaction, etc. The processing is performed by removing the material from the local area using various appropriate mechanical means, and the processing local area is sequentially removed at a predetermined position in the horizontal plane of the workpiece ceramic or in the thickness direction. A desired target process is performed by controlled movement. By doing this, high-temperature acid or alkaline processing fluid can be collected and removed from the processing section.
Even if there is a certain amount of recovered processing fluid, if cooling fluid is not required for mechanical processing, the amount can be extremely small, and there is little possibility that the recovered processing fluid will be in a high temperature state. Since there is no such thing, it is possible to construct a processing apparatus that achieves the object of the present invention. Examples of the energy supplied from the outside include laser beams, electrolytic discharge action (in the case of electrolytic discharge, so-called electrochemical action due to electrolysis, energization heating action due to electricity supply, heat and impact action due to discharge, etc.). complex action), for example, several tens of micrometers to 1
The heat is applied to a predetermined local range of μm, but no heat or the like is applied to other areas, making local processing possible. For example, according to a laser beam, if the energy density of the irradiated beam is 10 ⁶ watt/cm ² or more,
Can decompose and separate ordinary substances,
Since 10 ³ to 10 ⁴ watt/cm ² is approximately the energy density of heating, approximately 10 ⁵ is required to generally cause the acid or alkali reaction in ceramics in the high temperature range of the present invention. It is necessary to irradiate the workpiece with a light beam with an energy density of about watt/cm ² or more, but if you also use external energy such as energization, electrolysis, discharge, plasma, microwave, etc. The irradiation energy density of the above laser beam is
A minimum of 10 ² watt/cm ² or more is almost sufficient. The processing method of the present invention will be explained below with reference to the embodiments shown in the drawings. Fig. 1 is a front sectional view of an embodiment of an apparatus for carrying out the processing method of the present invention. controlled x
A cross table 2 having y-axis drive motors 3 and 4 is mounted on the cross table 2, and a processing table 5 having a workpiece 6 fixing device and preferably acid-resistant and/or alkali-resistant is provided on the cross table 2. ing. 7 preferably has a strong acid or strong acid group concentration such as hydrochloric acid (HCl), sulfuric acid (H ₂ SO ₄ ), nitric acid (HNO ₃ ), caustic soda (NaOH), or caustic potash (KOH) contained in the bed 1. It is a processing liquid storage tank at room temperature of about 5 to 50%, and 8 is its supply piping, but its pumping pump and the like are omitted.
A column 9 is provided upright at one end of the bed 1 and holds a mechanical grinding head 10 and an energy supply and machining fluid supply head 11. The head 10 includes, for example, an ordinary mechanical grinding wheel 10a and a motor (not shown) that rotationally drives the grinding wheel 10a, and the head 10 also controls and drives a Z-axis motor 10b by the aforementioned control device.
The Z-axis position of the grindstone 10a is controlled and set. Head 1
1 includes a laser oscillator, a microwave oscillator,
Or an energy generating device 1 such as an electron beam generator
1A and a machining fluid supply control device 11B are provided, and furthermore, at the tip of the head 11, a laser beam from the energy generator 11A is processed into a beam of a desired size using a reflecting mirror, a converging lens, etc. an energy irradiation gun 11a that irradiates the area;
A machining fluid nozzle 11b is provided that controls the machining fluid and supplies it to the machining section by spraying, flowing, etc. 12 is a cover that prevents machining debris and machining fluid from scattering and collects generated gas, mist, steam, etc. In particular, it collects gas and mist that is generated due to strong dispersion or strong base machining fluid's high temperature and reaction. This is then taken out by a suction pump 13, sent to a detoxification processing device 14 for such gases, mist, etc., and subjected to predetermined processing before being discharged. In the above case, the cooling liquid for grinding by the grindstone 10a is supplied to the nozzle 11b.
If the excess machining fluid caused by the grinding process or the decomposition or melted matter on the ceramic workpiece 6 cannot be used, a separate, independent, for example, ordinary grinding fluid (for cooling) supply means is provided to the grinding wheel 10a. will be established. Next, to explain the operation, the machining fluid nozzle 1
1b, a predetermined amount is intermittently applied to the next desired processing area of the workpiece 6 made of ceramics, or a predetermined minute flow rate (for example, 1 to 10 c.c./s) and a predetermined flow velocity (for example, 10 to 100 m/s). Then, the machining fluid is sprayed continuously in a thin film with a width, and a laser beam of at least 10 ² watt/cm ² , usually at least
It is irradiated with an energy density of about 10 ⁵ watt/cm ² in the thickness direction of the grinding wheel 10a while oscillating at 100 KHz to 200 MHz, and the supplied machining fluid and the workpiece 6 in that part are irradiated.
By instantaneously heating the surface of the part to a high temperature, the ceramic in the part concerned is decomposed or melted, or in the case of composite ceramics, only a part of the ceramic material is decomposed or melted, thereby weakening the entire part, This portion is then mechanically ground using a grinding wheel to remove decomposed or dissolved substances and weakened substances. Therefore, by sequentially applying the above-mentioned machining action using pre-programmed numerical control signals, etc. to process a predetermined width and a predetermined depth at a desired location, it is possible to remove a mere surface portion. In addition to chamfering, drilling and three-dimensional shape processing are also possible. At that time, unless the irradiation energy density from the energy irradiation gun 11a is extremely high, the grinding wheel 1
Since the blade 0a does not stand against the unprocessed part of the workpiece 6, it will not break, and the amount of machining fluid supplied from the nozzle 11b and the supplied machining fluid can be used to decompose the ceramics of the workpiece 6, Irradiation energy (laser of at least 10 ² watt/cm ² or more, discharge, plasma, microwave, electric current or electrolytic current,
Machining proceeds with machining performance determined by the irradiation control state (or ultrasonic vibration). Also, by controlling the swing of the energy irradiation gun 11a,
By using a laser beam to prevent clogging and sharpen the grindstone 10a as needed, the grinding performance of the grindstone 10a can be kept high, and the processing performance can be kept high. FIG. 2 is a cross-sectional view illustrating the configuration of another embodiment, in which parts given the same reference numerals as those in FIG. 1 indicate the same parts or the same effects. In this embodiment, the head 10,1
Processing fluid nozzle 11b held vertically downward from 1
With the center axis as the central axis, an energy irradiation gun 11a such as a laser beam and, for example, a honing nozzle 10c for performing mechanical grinding are configured so that rotation indexing and positioning can be performed by controlled rotation,
For example, when the workpiece 6 ceramics is a relatively thin plate-shaped piece and is to be cut into a predetermined contour shape, the machining liquid supplied from the nozzle 11b to the surface of the workpiece 6 is In contrast to the process in which the energy irradiation gun 11a is always positioned either in front of or behind the current direction of progress of processing, or on the side in a direction perpendicular to the direction of progress, even if the direction of progress of processing changes, processing proceeds. The honing nozzle 10c that performs mechanical processing is not always opposed to the energy irradiation gun 11a, and the honing injection is performed at the same time as the machining fluid is supplied or after the energy beam has been irradiated. The honing nozzle 10c is designed so that it can always be positioned on the left or right side in the direction perpendicular to the direction of progress of machining, or at the rear or front of the direction of progress of machining. That is, in the illustrated embodiment, the holding shaft 11 of the machining fluid nozzle 11b, which is held hanging from the heads 10 and 11,
A rotary disk 15 has a honing nozzle 11c attached to c so as to point toward the tip of the nozzle 11b,
The energy irradiation gun 11a is attached to the nozzle 11b via a gear 17 so that the energy irradiation gun 11a can be controlled and rotated by a motor 16 provided on the heads 10 and 11.
A rotary disk 18 is attached to the rotary disk 15 so that the tip thereof is oriented so as to be rotatable under control via a gear 20 by a motor 19 provided on the heads 10 and 11. In the illustrated case, when the energy irradiation gun 11a is a laser beam, it is necessary to supply the laser beam through a flexible optical fiber or the like, but when supplying a microwave or plasma, it is necessary to supply the laser beam through a pair of electrodes. In the case of a configuration in which energization or discharge is performed through a machining fluid, a different configuration will be adopted. Figure 3A,
B is a side view and a top view of a portion showing an example of a configuration in which external energy is supplied by energization, energization electrolysis, or electrolytic discharge from sources other than the energy irradiation gun 11a, and machining fluid 11 supplied from the nozzle 11b.
d, the heat-resistant and wear-resistant electrodes 22 attached to the tips of the pair of elastic lead arms 21 extending from near the tip of the irradiation gun 11a come into contact with the surface of the workpiece 6, and the machining fluid 11d is heated by electricity, electrolyzed by electricity, Furthermore, high temperatures are generated by electric discharge or electrolytic discharge, and especially in the case of electric discharge, thermal effects and discharge shocks also act strongly. In addition, in the case of the above Fig. 2, the honing nozzle 10c
Instead of a small rotary grinding wheel, cutting tool,
Alternatively, an arm equipped with an ultrasonic vibration machining tool may be provided to enable posture control, etc., if necessary, and each rotary disk 15 and 18 may be provided with a plurality of mechanical machining means, the same or different types, respectively. Alternatively, a plurality of energy irradiation guns of the same or different types may be provided to carry out the processing. FIG. 4 is an explanatory view of another embodiment of the processing method of the present invention, in which a processing liquid nozzle 11b with a wide and flat tip is used to inject hydrochloric acid (HCl) with a concentration of 5 to 40%, for example.
is ejected at a speed of about 10 m/s to 100 m/s and at a flow rate of about 1 to 10 c.c. in a film shape to match the width of the grinding wheel 10a of about 10 mm, superimposing ultrasonic vibrations as necessary. , to this film-shaped jetting liquid,
The nozzle 11b is used as one electrode 11e (+ pole),
Then, a voltage of direct current, alternating current, high frequency, or intermittent voltage pulses is applied between an arm 23 extending forward from the nozzle 11b and the other electrode 24 provided in contact with the machining fluid ejected, thereby forming a film-like machining fluid. It is heated to a predetermined high temperature state by energization, electrolysis, and electric discharge and is supplied to the surface of the ceramic to be processed of the workpiece 6 to cause decomposition of the ceramic, a melted reaction layer, and a weakened layer 6a, which is then turned into a grinding wheel 10a. It is mechanically removed by grinding. In this case, it is desirable that the grindstone 10a used be one that is strong against active oxygen, and the grindstone 10a may be one that does not have electrical conductivity _; of,
For example, in the case of a conductive grindstone 10a made of 30 to 100μ conductive TiC, TiN, etc. mixed, molded, and sintered, the grindstone 10a is connected to the negative electrode as shown in the figure to prevent wear and tear of the grindstone 10a. It is desirable to do so. FIG. 5 is a side view showing a processing method according to another embodiment, in which the power source (not shown) for energization, electrolysis, and discharge is connected to an electrode 25 provided at the tip of an arm 23 extending forward from the nozzle 11b. The grindstone 10a is connected as a negative electrode between the electrode 25 and the conductive grindstone 10a, and the electricity, electrolysis, and discharge between the electrode 25 and the grindstone 10a are also performed through the machining fluid interposed between them. Workpiece 6 Ceramics When the relevant part becomes high temperature, the conductivity of the ceramic increases according to the temperature. Therefore, as shown by symbol D, the electrode 25 is connected to the high temperature low resistance part of the ceramic or the electrode 25 material to the part. Grinding wheel 10 using the deposit as an intermediate electrode
An electric discharge is generated between the two and a, and machining is performed while further heating the machining fluid and the ceramic surface. In this case, when the workpiece 6 is made of Al ₂ O ₃ ceramics, the processing fluid is 40% NaOH, the grindstone is a conductive grindstone #150 with a width of about 10 mm as described above in Fig. 4, and the grinding speed is about 1500R. PM, copper (Cu) is used as the electrode 25, the power supply voltage is approximately 90V, the voltage pulse width is approximately 30μs, the pause width is approximately 50μs, and the discharge current amplitude is approximately
30A, cutting depth of about 5μm, machining feed rate of about 10m/min
The processing speed was approximately 0.5 cm ³ /min, and the machined surface roughness was approximately 0.5 μm Rmax or less. In the above case, if the surface of the workpiece 6 where the machining fluid is located between the electrode 25 and the grinding wheel 10a is continuously or intermittently irradiated with a laser beam, this will work not only for heating but also as a trigger for electric discharge, resulting in machining. Performance can be further improved. In addition, in the case of an energization method that performs energization, electrolysis, and even discharge, including the cases shown in Figs. 3 and 4, the electrolyte in the machining fluid is, for example, salt (NaCl) or potassium chloride (KCl). Even if the salt is a neutral salt, it does not necessarily have to be a strong acid or a strong alkali because an acid is generated at the positive electrode and an alkali is generated at the negative electrode by electrolysis. Furthermore, the decomposition and dissolution of ceramics by high-temperature acids or alkalis can be prevented at least by applying ultrasonic vibrations to the relevant parts (energy density
(approximately 10 ² watt/cm ² or more) is effective because the reaction is accelerated, and it is desirable to use it in combination with applying vibration to the workpiece 6. As described in detail above, according to the present invention, at least a portion of ceramics to be processed is locally decomposed, dissolved, or otherwise reacted with a high-temperature acid or alkaline processing liquid, and partially weakened. The purpose of ceramics processing has been achieved by applying a special composite processing method in which parts are removed using mechanical processing means, and ceramics is expected to be widely applied in the future for home use and various industrial uses. can be applied easily and inexpensively.

[Brief explanation of the drawing]

Figure 1 is a front cross-sectional view of an apparatus for implementing the processing method of the present invention, Figure 2 is a front view of a portion of the apparatus of another embodiment, and Figures A and B are views of another embodiment of the apparatus. A side view and a top view of the parts, and FIGS. 4 and 5 are respectively explanatory diagrams of the configuration of other embodiments. 6... Workpiece ceramics, 10a... Grinding wheel, 10c... Honing nozzle, 11d...
Machining fluid, 11b... Machining fluid supply nozzle, 11a...
...Energy irradiation gun, 22, 24, 25... Electrode.

Claims (1)

[Scope of Claims] 1. A processing liquid in which an acid or alkaline electrolyte is dissolved in water is applied to the surface area of a desired processing portion of a ceramic workpiece by immersion or the like,
A method for processing ceramics, which comprises performing machining in which energy is applied to a surface region of the processed portion to alter the quality of the processed portion, and then the altered portion is mechanically removed. 2. The method for processing ceramics according to claim 1, wherein the processing liquid is a strong acid such as hydrochloric acid, sulfuric acid, or nitric acid. 3. The method for processing ceramics according to claim 1, wherein the processing liquid is a strong base such as caustic soda or caustic potash. 4. The method for processing ceramics according to any one of claims 1 to 3, wherein the energy applied to the surface area of the processed part is ultrasonic vibration energy. 5. The method for processing ceramics according to any one of claims 1 to 3, wherein the energy applied to the surface area of the processing portion is a current applied to the processing fluid. 6. The method for processing ceramics according to any one of claims 1 to 3, wherein the energy applied to the surface area of the processed part is electrical discharge energy. 7. The method for processing ceramics according to any one of claims 1 to 3, wherein the energy applied to the surface area of the processed portion is an electromagnetic wave, particularly a laser beam. 8. The method for processing ceramics according to any one of claims 1 to 3, wherein the energy applied to the surface area of the processed portion is electromagnetic waves, particularly ultra-high frequency microwaves. 9. The energy applied to the surface area of the processed part is a combination of two or more of ultrasonic vibrations, electric current applied to the processing fluid, electrical discharge energy, or electromagnetic waves such as laser beams or ultrasonic microwaves. The ceramic according to any one of claims 1 to 3, wherein the two or more energies are applied at the same time or at short time intervals that can influence each other. Processing method. 10. The method for processing ceramics according to any one of claims 1 to 9, wherein the machining is cutting using a cutting tool. 11. The method for processing ceramics according to any one of claims 1 to 9, wherein the machining is a grinding process using abrasive grains or a grindstone. 12. The method for processing ceramics according to any one of claims 1 to 9, wherein the machining is an abrasive processing in which abrasive grains are injected with one or both of gas and liquid. 13. Claim 1, wherein the machining is electrolytic or electrolytic discharge grinding using a conductive disc or cylindrical rotating grindstone and using the grindstone as a negative electrode.
9. The method for processing ceramics according to any one of items 9 to 9.