JP3669073B2 - Grinding apparatus and grinding method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a grinding apparatus and a grinding method for performing grinding using a grindstone, and in particular, a grinding apparatus and a grinding process capable of processing with extremely small surface roughness and high shape accuracy. Regarding the method.
[0002]
[Prior art]
  In grinding processing, if the surface roughness is to be reduced, the abrasive grain size used is small, that is, a grindstone with a large grindstone is used. Get up to. For this reason, it is difficult to efficiently perform processing with extremely small surface roughness, so-called mirror grinding. As means for solving this problem, for example, there is a technique disclosed in Japanese Patent Laid-Open No. 3-196968.
  In this technique, grinding is performed with a metal bond grindstone using fine abrasive grains, an electrode is provided so as to face the grinding surface of the grindstone, and an electrolytic solution is supplied between the electrode and the grindstone. And a voltage is applied between a grindstone and an electrode, and the dressing (sharpening) by an electrolytic action is performed. With this technology, processing waste clogged between abrasive grains can be removed by electrolytic action, eliminating processing abnormalities such as increased grinding resistance due to clogging of the grinding wheel, grinding burn, and surface grinding, and surface roughness. This enables small processing.
[0003]
  On the other hand, in order to perform grinding processing with high shape accuracy, it is necessary to perform truing of the grindstone (processing of the outer peripheral shape of the grindstone, reshaping) in advance.
  For the shape processing of the metal bond grindstone, mechanical processing methods such as a method using a diamond truer and a method of rubbing using another grindstone are known. However, such a method has a drawback in that a large reaction force acts on the grindstone, so that the position of the grindstone is displaced and the processing accuracy is deteriorated, or the desired shape cannot be obtained due to wear of the truer itself. there were. As techniques for solving these problems, there are those disclosed in Japanese Patent Publication No. 2-38346, Japanese Patent Laid-Open No. 3-196968, and Japanese Patent Laid-Open No. 6-261066.
[0004]
  The technology disclosed in Japanese Examined Patent Publication No. 2-38346 is a technique for correcting the shape of a grindstone (truing) by electric discharge machining using a traveling wire, and can ignore the machining reaction force, and further, The consumption can be made small enough to be ignored. This technology also enables truing on a processing machine that performs grinding, eliminating the need for removal of the grindstone, and greatly improving efficiency and accuracy compared to conventional truing machines. Is done. However, in this method, since the position of the grinding wheel at the time of grinding and the electrode wire for electrical discharge machining are separated, it is assumed that an NC machine tool is used. To perform electrical discharge machining, the grinding wheel is controlled by an NC device. Therefore, it is moved to the place where electric discharge machining is performed. Therefore, although it is not necessary to remove the grindstone, the processing must be interrupted each time the grindstone needs to be formed, and the grindstone must be moved to the position where the wire travel device is installed. For this reason, there are disadvantages that the working efficiency is lowered, the positioning error caused by moving the grindstone for a long distance is increased, and the machining accuracy is lowered.
[0005]
  The technique disclosed in Japanese Patent Laid-Open No. Hei 3-196968 performs truing together with dressing of a grindstone. The electrode is brought into contact with the grinding surface of the grindstone at a predetermined pressure, and a machining fluid is interposed in this portion, thereby A voltage is applied between the two. With such a configuration, an electrochemical action, a chemical action, a mechanical action, and a discharge action work, and truing is performed for dressing of the grindstone. However, since the electrode is in contact with the grindstone, there are a drawback that the electrode is consumed and a processing accuracy is deteriorated similarly to truing by mechanical processing. Therefore, although this technique is mainly effective for dressing (sharpening), the truing accuracy is limited, and particularly high-precision processing cannot be expected.
[0006]
  The grinding device disclosed in Japanese Patent Application Laid-Open No. 6-210566 has a wire electric discharge machining device supported so as to be capable of relative movement with respect to the grinding wheel, and performs truing of the grinding wheel while detecting the shape of the grinding surface of the grinding wheel. To do. That is, the electric discharge machining apparatus is supported by a table that can move relative to the grinding surface of the grindstone in the width direction and the vertical direction, and detects the discharge start position (discharge start gap) of the wire electrode in the electric discharge machining apparatus. Be able to. Thus, a change in the shape of the grinding surface of the grindstone is detected during grinding of the workpiece, and truing (molding) of the grindstone is performed in accordance with this change. Therefore, truing is performed in response to the shape change caused by the wear of the grindstone caused during processing, and grinding processing with extremely high shape accuracy can be realized.
[0007]
  Thus, a technique for performing processing with a small surface roughness or processing with high shape accuracy has been developed in the past, and by using the electrolytic in-process dressing technique described in Japanese Patent Laid-Open No. 3-196968, extremely Processing with small surface roughness is realized, and processing with extremely high shape accuracy is possible by applying the discharge truing technique described in Japanese Patent Laid-Open No. 6-210666.
[0008]
[Problems to be solved by the invention]
  However, with respect to performing grinding with extremely small surface roughness and extremely high shape accuracy, the above conventional technique cannot provide sufficient results.
  In the technique described in the above-mentioned Japanese Patent Laid-Open No. 3-196968, even if the truing of the grindstone is first performed with high accuracy, a minute change occurs in the shape of the grindstone while performing grinding while performing dressing. This is due to the fact that the electrolytic action used for dressing acts on the processing waste adhering to the surface of the grindstone and at the same time affects the grindstone itself. In other words, it acts by acting on the metal binding material that holds the abrasive grains to melt or alter them, so that the grinding wheel is consumed or the grinding wheel diameter is changed, and the shape accuracy of the workpiece after grinding It is extremely difficult to carry out precise processing such that the thickness is 5 μm or less, particularly 1 μm or less.
[0009]
  In addition, it is conceivable to correct such deformation of the grindstone by truing. It has been considered that it is difficult to perform both the electrolytic in-process dressing technique and the discharge truing technique on a grindstone that is not obtained and is in a position for grinding. The reason is that the machining fluid interposed between the grindstone and the electrode during the electrolytic machining is an electrolytic solution, and the machining fluid interposed between the discharge electrode and the grindstone causes an electrical discharge to cause discharge. This is because the processing fluids are mixed when these are supplied to the grindstone at the same position, and normal electrolysis or discharge does not occur.
[0010]
  The present invention has been made in view of the circumstances as described above, and an object of the present invention is to provide a grinding apparatus and a grinding method capable of realizing machining with a small surface roughness and extremely high shape accuracy. That is.
[0011]
[Means for Solving the Problems]
  In order to solve the above-described problems, the invention according to claim 1 is directed to a conductive grindstone that contacts a workpiece in a rotationally driven state and performs grinding, and the grindstone is used as a workpiece. Whetstone support means for supporting the movably relative to,A working fluid supply means for supplying a working fluid to a surface of the grindstone that contacts the workpiece;  Proximity facing the grinding wheelFirstWith electrodes,The firstBetween the electrode and the grindstoneThe machining fluidAnd dressing means for sharpening by electrolytic action, and arranged so as to be close to the grindstone, and support the adjustment of the relative position with the grindstoneThe grinding wheel is reshaped by electric discharge in a state where the working fluid is interposed between the second electrode and the grinding wheel.An electrical discharge machining device,The machining fluid is adjusted to a volume resistivity that causes an electrolytic reaction between the electrode and the grindstone, and generates electric discharge between the electric discharge machining apparatus and the grindstone, and the dressing The means and the electric discharge machining apparatus are arranged at different positions.A grinding apparatus is provided.
[0012]
  In the above configuration, the conductive grindstone includes a conductive material, so that a voltage can be applied between the grindstone and the electric field electrode, or between the grindstone and the electric discharge machining electrode, For example, a metal bond grindstone in which abrasive grains are hardened with metal can be used. At this time, the abrasive may be a conductive material or a non-conductive material.
[0013]
  In such a grinding apparatus, it is possible to perform grinding while moving the rotationally driven grindstone relative to the workpiece, and to process the workpiece into a desired shape and size. Become. In addition, since the dressing means is provided opposite to the grindstone supported at the position where the workpiece is ground as described above, when the grindstone is clogged, the dressing can be quickly performed. This makes it possible to process with extremely small surface roughness. In other words, by causing an electrolytic action between the electrode and the grindstone, if the grinding scraps clogged between the abrasive grains are conductive, the surface of the grinding scraps is eluted directly, and the grinding scraps are removed from between the abrasive grains. Removed. Further, even if the grinding scraps are non-conductive, a gas such as oxygen is generated on the surface of the bonding metal of the abrasive grains, the grinding scraps are removed by the expansion pressure of the bubbles, and the dressing is performed quickly.
[0014]
  In addition, an electrical discharge machining device is installed in close proximity to the grinding wheel at the position where grinding is performed, and when there is a change in the shape of the grinding surface of the grinding stone, truing by electrical discharge machining can be performed immediately. The shape of the grindstone can be maintained with extremely high accuracy.
  Therefore, the grindstone is always free from clogging and maintained in a state with high shape accuracy, and processing with extremely small surface roughness and high shape accuracy is possible.
[0015]
  further,In this grinding apparatus, since the same machining fluid is supplied between the electrode of the dressing means and the grindstone, and between the discharge electrode of the electric discharge machining apparatus and the grindstone, it is supplied to both positions by the rotation of the grindstone. It is not a problem that the processing fluid is mixed,A working fluid with a properly adjusted volume resistivityBy selecting, both dressing by electrolytic action and truing by electric discharge machining can be performed simultaneously with grinding.
[0016]
  The invention according to claim 2 is the grinding apparatus according to claim 1,The machining fluid supply means includes a first machining fluid supply device that supplies the machining fluid to a position where the electrode of the dressing means faces the grindstone, and a discharge electrode of the electric discharge machining device that faces the grindstone. A second machining fluid supply device for supplying the machining fluid.
[0017]
  In this grinding apparatus, the first machining fluid supply means or the second machining fluid supply means is operated to supply the machining fluid while grinding the workpiece, so that dressing or truing can be performed efficiently. .
[0018]
  The invention according to claim 3 is the grinding apparatus according to claim 1 or 2,The second electrode is a wire electrode that travels along a wire guide supported to face the grindstone.
[0019]
  In this grinding apparatus, since the wire electrode is used in the electric discharge machining apparatus, a machining error due to the consumption of the machining electrode is avoided, and the grindstone can be trued with high accuracy.
[0020]
  The invention according to claim 4The grinding apparatus according to any one of claims 1 to 3, wherein the volume resistivity of the machining fluid is 0.1 kΩm or more and 10 kΩm or less.
[0021]
  In this grinding method, the same machining fluid is supplied between the grinding surface of the grindstone and the electrode for electrolysis, and between the grinding surface of the grindstone and the discharge electrode. As shown in FIG. Further, it is desirable to use one having a resistance of 0.5 kΩm to 1.5 kΩm.
  By using a working fluid whose volume resistivity is in the above range, it is possible to perform dressing by electrolytic action by interposing between the grindstone and the electrode for electrolysis, or intervening between the grindstone and the discharge electrode. Electric discharge can be caused, and dressing by electrolysis and truing by electric discharge machining can be performed simultaneously. In other words, grinding can be performed while always performing dressing and truing of the grindstone, and using a grindstone with a small grind particle size, the surface roughness is extremely small, and grinding with high shape accuracy is possible.
[0022]
  The invention described in claim 5A first step of grinding by bringing the grinding wheel into contact with a workpiece and simultaneously supplying the machining fluid to the grinding surface of the grindstone; A second step of applying a voltage between the electrode for electrolysis disposed in close proximity to the grindstone and the grindstone to make sharpening by electrolytic action, and simultaneously supplying the processing liquid to the grinding surface of the grindstone, And a third step of reshaping the grindstone by discharge between the discharge electrode disposed in close proximity to the grindstone and the grindstone, and the working fluid includes the electrode and the grindstone The volume resistivity is adjusted so as to cause an electrolytic reaction between the electric discharge machine and the electric discharge between the electric discharge machining device and the grindstone, and without moving the position of the grindstone, Switch from process to third process arbitrarily The present invention provides a grinding method characterized by cutting a workpiece.
[0023]
  The invention according to claim 6While supplying the processing liquid to the grinding surface of the grindstone that is driven to rotate, the grindstone is brought into contact with the workpiece to perform grinding, and between the electrode for electrolysis disposed adjacent to the grindstone and the grindstone. A first step of applying a voltage to the electrode to make sharpening by electrolytic action; supplying a working fluid to the grinding surface of the grindstone; simultaneously bringing the grindstone into contact with the work piece and performing grinding; and proximity to the grindstone A second step of reshaping the grindstone by discharge between the discharge electrode disposed opposite to the grindstone, and the working fluid undergoes an electrolytic reaction between the electrode and the grindstone. And the volume resistivity is adjusted so as to generate electric discharge between the electric discharge machining apparatus and the grindstone, and the first or second is adjusted without moving the position of the grindstone.Provided is a grinding method characterized by cutting a workpiece by arbitrarily switching processes.
[0024]
  In this grinding method, it is possible to arbitrarily switch between the step of performing dressing by electrolytic action while grinding the workpiece, and the step of performing truing by electric discharge while grinding, so that the grinding wheel being ground Depending on the condition, dressing or truing can be performed. That is, dressing by electrolytic action can be performed when clogging of the grinding surface of the grindstone progresses, and truing by electric discharge machining can be performed when the shape of the grindstone progresses. Therefore, even if the degree of clogging or shape change varies depending on the material of the workpiece, it can be easily handled, and grinding can be performed while always maintaining the grindstone in a good state.
[0025]
  The invention according to claim 7 includes a step of supplying a machining liquid to a grinding surface of a grindstone that is driven to rotate, a step of bringing the grindstone into contact with a workpiece, and grinding, and being disposed in close proximity to the grindstone A step of applying a voltage between the electrode for electrolysis and the grindstone to perform sharpening by electrolytic action, and a discharge between the discharge electrode and the grindstone disposed in close proximity to the grindstone, And a step of reshaping, wherein the machining liquid causes an electrolytic reaction between the electrode and the grindstone, and generates an electric discharge between the electric discharge machining apparatus and the grindstone. Provided is a grinding method characterized in that the volume resistivity is adjusted.
[0026]
  The invention according to claim 8 is the grinding method according to any one of claims 5 to 7, wherein the volume resistivity of the machining fluid is 0.1 kΩm or more and 10 kΩm or less. To do.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, embodiments of the present invention will be described with reference to the drawings.
  FIG.Of the present inventionIt is a schematic block diagram which shows the grinding processing apparatus which is one Embodiment.
  The grinding apparatus includes a grindstone 2 that performs grinding by contacting a workpiece (workpiece) 3 while rotating, a main shaft 1 that rotationally drives the grindstone 2, and a grindstone support member that rotatably supports the main shaft 1. 15 and a support 1a for fixing the grindstone 2 to the main shaft 1 are provided. Further, between the grindstone 2 and the electrolytic dressing electrode 5 that is dressed by electrolytic action by interposing a working fluid (electrolytic solution) between the grindstone 2 and the circumferential surface of the grindstone 2. An electric discharge machining head 8 which causes electric discharge to reshape by electric discharge machining, a grinding portion where the grindstone 2 and the workpiece 3 face each other, an electrolytic dressing portion where the grindstone 2 and the electrolytic dress electrode 5 face each other, and the grindstone 2 A first nozzle 11, a second nozzle 12, and a third nozzle 13 are provided each for ejecting and supplying a machining liquid to an electric discharge machining portion facing the electric discharge machining head 8.
[0028]
  The grindstone 2 is rotationally driven by the rotation of the main shaft 1 supported by the grindstone support member 15, and the axis of the main shaft 1 while rotating by a moving mechanism (not shown) attached to the grindstone support member 15. It moves in the direction and the vertical direction. The grindstone 2 is conductive so as to perform dressing during grinding. In this example, the bond material which is a base material of the grindstone 2 is composed of a metal mainly composed of iron or copper, and a metal bond grindstone in which abrasive grains are hardened with the bond material is employed. This bond material contains abrasive grains and has a role of holding the abrasive grains exposed on the surface of the grindstone 2. The abrasive grains may be either conductive or non-conductive materials, but in this example, non-conductive materials are used.
[0029]
  The work 3 is fixedly supported on a table 4 installed on a support base 14 and is moved in the direction of arrow A (left-right direction) shown in the figure by a moving mechanism of the table 4. And the surface of the workpiece | work 3 can be processed into a free shape by moving the table 4 and the said grindstone support member 15 and controlling the contact location with the grindstone of the workpiece | work 3 to arbitrary positions. The workpiece 3 may be either a conductive material or a non-conductive material, but it is desirable to set an appropriate working fluid or the like according to the material of the workpiece.
[0030]
  The electrolytic dress electrode 5 is connected to a power source 6 for electrolysis by a wiring 7a, and the other wiring 7b is connected to the main shaft 1 by a brush (not shown). A constant voltage or a pulse voltage with a special pattern is applied from the power source 6 for electrolysis through the wiring 7, and electrolysis is performed between the electrode 5 and the grindstone 2 by interposing a processing liquid supplied from the second nozzle 12. It is designed to cause an action. In this example, the voltage applied from the electrolysis power supply 6 is 90 V, and the current having a peak value of 10 A is controlled to flow in a pulse manner in which the current flows for 2 μs and pauses for 2 μs. In this case, the polarity is positive on the rotating spindle 1 side of the grindstone 2 and negative on the electrolytic dressing electrode 5 side. The length of the electrolytic dress electrode 5 (length in the circumferential direction of the grindstone) is about 1/5 to 1/4 of the entire circumference of the grindstone, and the width is set to be about the same as the width of the grindstone or about 0.5 mm. The material of the electrolytic dress electrode 5 is copper having good conductivity, and the distance between the electrode 5 and the grindstone 2 is set to about 0.15 to 0.3 mm.
[0031]
  The electric discharge machining head 8 is connected to an electric discharge machining power supply 9 by a wiring 10a, and the other wiring 10b from the electric discharge machining power supply 9 is connected to the main shaft 1 by a brush (not shown). A voltage is applied from the electric discharge machining power source 9 to generate an electric discharge between the electric discharge machining head 8 and the grindstone 2. The polarity in this case is negative on the electric discharge machining head 8 side and positive on the main shaft 1 side. As discharge generation conditions, the voltage is 200 V, the capacitor capacity is 100 pF, and the charging resistance is 1.1 kΩ. The distance between the electric discharge machining head 8 and the grindstone 2 is set to about 2 μm in order to generate an appropriate electric discharge.
[0032]
  FIG. 2 shows details of the electric discharge machining head 8. The electric discharge machining head 8 has a wire travel mechanism disposed on a base plate 81 made of ceramic, and uses a traveling electrode wire 82 as an electrode for electric discharge machining. The electrode wire 82 has a diameter of 0.1 mm and is made of brass. As shown in FIG. 2A, a feed bobbin 83, a take-up bobbin 91, a brake roller 84, rotary rollers 85, 86, 87 and the like of the electrode wire 82 are rotatably supported on the base plate 81. 83 is prepared in a state where a necessary wire amount is wound around 83 in advance. There are three grooves around the brake roller 84, so that the electrode wire 82 from the delivery bobbin 83 and the electrode wire from the rotating rollers 85 and 86 are received by separate grooves, and the electrode wire during running is entangled. There is no consideration. The brake roller 84 can rotate around its axis, but the shaft has a mechanism (not shown) that suppresses the periphery of the shaft and suppresses rotation by friction, so that the wire has a direction opposite to the traveling direction. The tension is applied to. This prevents loosening of the wire and avoids troubles such as dropping of the wire from the wire guide 89 described later.
[0033]
  A wire guide 89 is attached on the downstream side of the brake roller 84 and the rotating roller-87 so as to protrude from the base plate 81, and the wire guide 89 is disposed so as to face the grindstone 2. The wire guide 89 is screwed to the tip of the guide arm 88 and does not rotate. Around the wire guide 89, a guide groove having the same width as the diameter of the wire is engraved, and the wire travels along the guide groove. The guide groove is about half the diameter of the wire and has a semicircular cross section, and half of the electrode wire 82 to be guided is supported in a state of protruding outside the wire guide. A discharge is generated between the electrode wire 82 and the grindstone 2 in the exposed portion.
  The take-up bobbin 91 is behind the base plate 81 and is driven to rotate by a motor (not shown), and serves to take up the electrode wire 82 that has passed through the wire guide 89 and the rotating roller 90.
[0034]
  In the electric discharge machining head 8 having such a mechanism, the electrode wire 82 delivered from the delivery bobbin 83 first travels in the form of reciprocating the rotating rollers 85 and 86 that can rotate around the axis by changing the direction by the brake roller 84. To do. The electrode wire 82 exiting from the brake roller 84 is subsequently changed in direction by the rotating roller 87 and sent to the wire guide 89. When the wire guide 89 travels, a discharge is generated between the electrode wire 82 and the grindstone 2 by the voltage applied from the electric discharge machining power source 9, and the electric discharge machining of the grindstone 2 is performed. Then, the electrode wire 82 that has passed the wire guide 89 changes its direction via the rotating roller 90 and is sent to the winding bobbin 91.
[0035]
  The electrode wire 82 is configured to travel along the periphery of the wire guide 89 by the mechanism as described above. By replacing the wire consumed by the electric discharge machining with a new portion by traveling, a grindstone can be obtained. 2 is controlled to be constant. It is appropriate to run the wire 82 at a speed of about several tens of mm per minute.
[0036]
  As shown in FIG. 2B, the electric discharge machining head 8 is fixedly supported on a vertical movement table 93 by a mounting shaft 92, and the vertical movement table 93 is shown on an L-shaped horizontal movement table 94 with an arrow shown in the figure. It is supported so as to be movable in the direction B. The horizontal movement table 94 is supported by a projection 15a provided on the grindstone support member 15 so as to be movable in the direction of arrow C shown in the drawing. By controlling these tables, the electric discharge machining head 8 can be controlled to move in two directions, which are vertical or horizontal with respect to the rotation of the grindstone 2. Accordingly, the distance between the grindstone 2 and the electric discharge machining head 8 can be controlled to a distance at which electric discharge machining can be performed, and the grindstone can be shaped into an arbitrary shape by moving over the width of the grindstone.
[0037]
  Next, the working fluid used in this grinding apparatus will be described.
  The machining liquid is supplied from the first nozzle 11 between the grindstone 2 and the workpiece 3 in order to lubricate, cool, and clean the grinding surface. However, the machining liquid supplied from the second nozzle 12 is electrolyzed. This is because an electric current is caused to flow in the dressing portion to cause an electrolytic reaction, and the supply of the machining liquid from the third nozzle 13 is for insulating the electric discharge machining portion and generating electric discharge. In general, it is considered ideal that the machining fluid supplied to these three locations, particularly the electrolytic dressing portion and the electric discharge machining portion, should be selected separately for each application. Since the rotation is very high, thousands to tens of thousands of rpm, each machining fluid is mixed, and it is very difficult to use separate machining fluids. Therefore, here, the same machining fluid is supplied, and the machining fluid satisfying the functions of the respective parts is set.
[0038]
  The used working fluid is used by further diluting an electrolytic solution commercially available for electrolytic dressing from a concentration generally used. This is because the insulating properties necessary for electric discharge machining cannot be obtained with the concentration of the electrolytic dressing solution generally used. Actually, discharge can be generated when the volume resistivity of the machining fluid is 100 Ωm or more, and stable electric discharge machining can be performed when the volume resistivity is about 1 kΩm or more. If the volume resistivity is further increased, the electric discharge machining is improved, but it is difficult to obtain a current necessary for electrolysis. Therefore, the range of the volume resistivity of the electrolytic solution is 0.1 kΩm or more and 10 kΩm or less, preferably 0.5 kΩm or more and 1.5 kΩm or less.
[0039]
  Next, an operation of such a grinding apparatus, which is a grinding method according to an embodiment of the present invention, will be described.
  When the apparatus is started, the grindstone 2 is controlled to move relative to the workpiece 3 by a moving mechanism (not shown), and the workpiece 3 is scraped off while the abrasive grains of the grindstone 2 scrape the surface of the workpiece 3. Grinded to the shape and dimensions of And before clogging of the grindstone 2 advances by this grinding process, a voltage is applied between the electrolytic dressing electrode 5 and the grindstone 2 from the power supply 6 for electrolysis. As a result, an electrolytic action occurs between the electrolytic dress electrode 5 and the grindstone 2, and grinding debris clogged between the abrasive grains is removed by this electrolytic action, and the grinding stone 2 is dressed. At this time, if the grinding waste is conductive, the surface of the grinding waste is eluted directly, and the grinding waste is removed from the abrasive grains. On the other hand, when the grinding waste is non-conductive, the grinding waste can be removed by the gas generated on the surface of the electrolytic dress electrode 5 by the expansion pressure of the bubbles. Thereby, grinding waste can be removed without interrupting the grinding process, and an increase in the grinding resistance of the grindstone 2 can be prevented and good machinability can be maintained.
[0040]
  Further, when performing the dressing, a voltage is applied between the electric discharge machining head 8 and the grindstone 2 from the electric discharge machining power source 9. At this time, the electric discharge machining head 8 is controlled to move vertically or horizontally with respect to the grindstone 2 by the moving mechanism shown in FIG. As a result, electric discharge is generated between the electric discharge machining head 8 and the grindstone 2, and the grinding surface of the grindstone 2 is reshaped (truing) by electric discharge machining.
[0041]
  In such a grinding apparatus, grinding can be performed while simultaneously performing dressing and truing of the grindstone, and it is not necessary to interrupt the grinding process in order to perform these steps. For this reason, a grindstone having a small abrasive grain size can be used without reducing the grinding efficiency, and cutting with extremely small surface roughness and high shape accuracy can be performed.
[0042]
  next,Although the configuration is almost the same as that of the grinding apparatus shown in FIG. 1, an apparatus that uses different machining fluids during the dressing and the electric discharge machining and the operation of this apparatus will be described as a reference example.
This grinding machineThe process of grinding the workpiece and simultaneously dressing the wheel with the electrolytic dress electrode and the process of grinding the workpiece and simultaneously truing the wheel by electric discharge machining are set to be switched arbitrarily. Yes. At this time, the working fluid supplied from each nozzle is also switched, and during the dressing, a normal electrolytic solution is ejected from the second nozzle between the electrode for electrolysis and the grindstone, and when switching to electric discharge machining, the third working fluid is supplied. An insulating liquid such as pure water is ejected from the nozzle between the discharge electrode and the grindstone. The other configuration of this grinding apparatus is the same as that of the grinding apparatus shown in FIG.
[0043]
  In such a grinding machine, the process of dressing while grinding the workpiece and the process of truing while grinding can be switched arbitrarily, and the clogging or shape change of the grinding wheel during grinding Depending on the situation, dressing or truing can be performed. For this reason, by selecting a working fluid suitable for each step, a higher dressing or truing effect can be obtained, and grinding can be performed while maintaining a good grindstone state.
[0044]
【The invention's effect】
  As described above, in the grinding apparatus or the grinding method according to the present invention, dressing can be performed promptly according to the degree of clogging of the grindstone without interrupting the grinding work. Truing can be performed according to the shape change. For this reason, clogging of the grindstone can be prevented and the shape of the grindstone can be maintained with high accuracy, and grinding processing with extremely small surface roughness and high shape accuracy can be performed.
  In addition, the processing liquid supplied to the facing position between the grindstone and the dressing means and the processing liquid supplied to the facing position between the grindstone and the electric discharge machining apparatus are made into the same processing liquid having an appropriate volume resistivity, so that the grinding process is performed. The grinding wheel dressing and truing can be performed simultaneously. For this reason, highly accurate and highly efficient grinding can be performed.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a grinding apparatus according to an embodiment of the present invention.
FIG. 2 is a front view and a side view showing details of an electric discharge machining head used in the grinding apparatus.
[Explanation of symbols]
    1 Spindle
    2 Whetstone
    3 Work
    4 tables
    5 Electrolytic dress electrode
    6 Power supply for electrolysis
    7 Wiring
    8 EDM head
    9 Power supply for EDM
  10 Wiring
  11 First nozzle
  12 Second nozzle
  13 Third nozzle
  15 Wheel support member
  81 Base plate
  82 Electrode wire
  83 Delivery bobbin
  84 Brake roller
  85, 86, 87, 90 Rotating roller
  88 Guide arm
  89 Wire guide
  91 Winding bobbin
  92 Mounting shaft
  93 Vertical moving table
  94 Horizontal moving table

Claims (8)

A conductive grindstone that contacts the workpiece in a rotationally driven state and performs grinding;
Whetstone support means for supporting the whetstone movably relative to the workpiece;
A working fluid supply means for supplying a working fluid to a surface of the grindstone that contacts the workpiece;
Dressing means comprising a first electrode that is proximately opposed to the grindstone, interposing the working fluid between the first electrode and the grindstone, and performing dressing by electrolytic action;
The second electrode is disposed so as to be close to the grindstone and supported so that the relative position of the grindstone can be adjusted, and the working fluid is interposed between the second electrode and the grindstone. An electric discharge machining device that reshapes the grindstone by electric discharge in a discharged state ,
Have
The machining fluid is adjusted to a volume resistivity that causes an electrolytic reaction between the electrode and the grindstone, and generates a discharge between the electric discharge machining apparatus and the grindstone,
The grinding apparatus characterized in that the dressing means and the electric discharge machining apparatus are arranged at different positions . The machining fluid supply means includes a first machining fluid supply device that supplies the machining fluid to a position where the electrode of the dressing means faces the grindstone, and a discharge electrode of the electric discharge machining device that faces the grindstone. The grinding apparatus according to claim 1, further comprising a second machining liquid supply device that supplies the machining liquid. The grinding apparatus according to claim 1, wherein the second electrode is a wire electrode that travels along a wire guide that is supported to face the grindstone. 4. The grinding apparatus according to claim 1, wherein a volume resistivity of the machining fluid is 0.1 kΩm or more and 10 kΩm or less. 5. A first step of performing grinding by bringing the grinding stone into contact with the workpiece while simultaneously supplying the machining liquid to the grinding surface of the rotationally driven grinding stone;
  A second step of supplying the working fluid to the grinding surface of the grindstone and simultaneously applying a voltage between the electrode for electrolysis disposed in close proximity to the grindstone and the grindstone to make sharpening by electrolytic action; ,
  And a third step of reshaping the grindstone by supplying electric power between the discharge electrode disposed in close proximity to the grindstone and the grindstone while supplying the working fluid to the grinding surface of the grindstone. And
  The working fluid is adjusted to a volume resistivity that causes an electrolytic reaction between the electrode and the grindstone, and generates electric discharge between the electric discharge machining apparatus and the grindstone,
  A grinding method characterized in that the workpiece is cut by arbitrarily switching from the first step to the third step without moving the position of the grindstone. While supplying the processing liquid to the grinding surface of the grindstone that is driven to rotate, the grindstone is brought into contact with the workpiece to perform grinding, and between the electrode for electrolysis disposed adjacent to the grindstone and the grindstone. A first step of applying voltage to the electrode to make sharpening by electrolytic action;
While supplying the processing liquid to the grinding surface of the grindstone, the grindstone is brought into contact with the workpiece to perform grinding, and the discharge between the discharge electrode arranged in close proximity to the grindstone and the grindstone causes the A second step of reshaping the grindstone,
The machining fluid is adjusted to a volume resistivity that causes an electrolytic reaction between the electrode and the grindstone, and generates a discharge between the electric discharge machining apparatus and the grindstone,
A grinding method characterized by cutting the workpiece by arbitrarily switching the first or second step without moving the position of the grindstone . Supplying a machining fluid to the grinding surface of the rotationally driven grinding wheel;
  Grinding the contact wheel in contact with the workpiece;
  A step of applying a voltage between the electrode for electrolysis arranged in close proximity to the grindstone and the grindstone to make sharpening by electrolytic action;
  Simultaneously performing a process of reshaping the grindstone by means of a discharge between the discharge electrode and the grindstone disposed close to and facing the grindstone,
  The machining fluid is adjusted to a volume resistivity that causes an electrolytic reaction between the electrode and the grindstone, and generates electric discharge between the electric discharge machining apparatus and the grindstone. Grinding method. The grinding method according to any one of claims 5 to 7, wherein a volume resistivity of the machining fluid is 0.1 kΩm or more and 10 kΩm or less.

Images