JPH0957622A - In-process electrolytic dressing grinding method - Google Patents

Abstract

(57) An object of the present invention is to provide an electrode that is arranged to face the working surface of a grindstone made of a metal-based bond material with a certain gap therebetween, and to fill an electrolytic field filled in the gap. In an in-process electrolytic dressing grinding method of grinding a workpiece while dressing the grinding wheel working surface by an electrolytic reaction by applying a voltage through a liquid, a plurality of grinding wheel working surfaces having different grinding performances By using a grindstone equipped with, it is possible to achieve the required machining accuracy and surface roughness with one grindstone in a short tact time, and reduce the setup time to improve productivity. To aim. SOLUTION: Each region W having different grinding performance
Grinding is performed on the workpiece 22 by using the grindstones 30 in which the grindstone working surfaces 31 and 32 of 1 and W2 are arranged in the pick feed Y direction while moving the grindstone working surfaces 31 and 32 to the workpiece 22.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an in-process electrolytic dressing grinding method for grinding glass, ceramics and the like.

[0002]

2. Description of the Related Art In recent years, in order to process difficult-to-cut materials such as ceramics with high efficiency, metal bond grindstones in which abrasive grains are firmly held have been developed and their effects have been recognized. However, these grindstones lack the truing property and dressing property, and it is difficult for the self-developing action of the abrasive grains to occur, so that stable processing by conventional grinding has been difficult. As a method for coping with these problems, an ELID grinding method, which is designed to promote a self-developing blade action during grinding, has been invented and has been attracting attention in recent years. 9A and 9B are principle views of the ELID grinding method. FIG. 9A is a front view thereof and FIG. 9B is a view thereof.
Is a sectional view. In this ELID grinding method, a grindstone 10 such as a metal-bonded diamond grindstone is used as an anode, an electrode 21 opposed to the working surface of the grindstone is used as a cathode, and a weak electrolytic solution is interposed between the anode and the cathode. This is a grinding method in which the bond material is eluted by an electrolytic action to dress the grindstone 10 in-process. In addition, 23 is an electrolyte solution supply part. During electrolysis by this grinding method, except for the edge portion of the grindstone 10, a uniform power line is generated between the grindstone 10 and the cathode, and the electrolysis phenomenon on the grindstone working surface, that is, the elution of the bond material and the formation of the non-conductive coating are uniform. . Therefore, the processing specifications such as the removal amount and surface roughness obtained by fixing the grinding condition and the electrolytic condition remain within a very limited range. The efficiency and accuracy of machining of steel materials such as Starbucks and various ceramics, optical glass, etc. by this grinding method, and the effect on precision were announced by "Presentation Society of Japan Precision Engineering Autumn Meeting, 1987, 687, etc." ing.

FIG. 10 is a schematic diagram showing the mechanism of the ELID grinding method. Examples of the bond material that holds the abrasive grains include metal materials such as cast iron, steel, and cobalt that are capable of electrolytically eluting ions with a weakly conductive water-soluble grinding fluid to form a nonconductive film. In FIG. 10, 10 is a grindstone for grinding when a bond material using cast iron as a matrix material is used, 11 is a bond material, and 12 is an abrasive grain. Figure 11 shows a grindstone 10
Is a diagram showing an array of abrasive grains in the case of a straight grindstone,
Abrasive grains 12 having a predetermined grain size are distributed in the bond material 11 having a uniform density over the entire circumference of the width W of the grindstone working surface (region of the grindstone working surface). FIG. 12 is a current characteristic diagram with respect to the progress of ELID grinding.

In FIG. 10, 10a is the grindstone immediately after truing, 10b is the grindstone at the start of electrolytic dressing (electrolytic current is -10A), and 10c is the grindstone at the completion of electrolytic dressing (electrolytic current). Is around 1A),
10d is the grindstone at the start of ELID grinding (electrolytic current is up to 1.5 A), and 10e is the grindstone at the time of progress of ELID grinding (electrolytic current up to 2 A). Immediately after truing, the grinding surface is a flat surface A (grinding stone
10a). In the initial electrolytic dressing, iron ions are eluted and the abrasive grains 12 are projected on the grinding surface to form the abrasive grain protruding portion B (grinding stone 10b). At the same time, the iron ions are combined with hydroxyl groups and oxygen ions to form iron hydroxide or oxide. Iron is produced and these are deposited on the surface to form the non-conductive coating C (grinding stone 10c).
When the non-conductive coating C has a certain thickness, the elution of metal ions is suppressed, and at the same time, the electrolytic current value also decreases as shown in FIG. When the abrasive grain protrusion B begins to wear and reaches the height of the non-conductive coating C (grinding stone 10d), the coating is scraped off by contact with the workpiece. When the film thickness becomes small to some extent (grinding stone 10e), ion elution occurs again,
Dressing starts again (grinding stones 10b, 10c). In this series of phenomena, the abrasive grains 12 do not fall off, and stable sharpness is maintained for a long period of time. During stable processing,
It is considered that the film thickness is constant because the removal of the film and the elution of the bond material and the formation of the film are balanced. On the other hand, for high-efficiency grinding in which the removal amount of the work material with respect to the work piece is increased, a grindstone using bronze or the like that does not form the non-conductive coating C as a bond material may be used.

As described above, in the ELID grinding method, since the dressing is performed during the processing, it is not necessary to interrupt the processing due to clogging to perform the dressing, which is superior in accuracy and efficiency to the conventional grinding method. There is.

[0006]

However, in such a conventional ELID grinding method, it is the same as the conventional grinding method in that it is necessary to use a grindstone having a specification corresponding to required surface accuracy, surface roughness and the like. Yes, for example, in order to obtain a high-quality ground surface of 0.1 μmRmax or less, # 140 → # 600 →
It is necessary to use # 4000 (rough processing → intermediate finishing → final finishing) and three types of grain sizes in three steps. in this case,
It is necessary to replace the grindstones, adjust the contact with each grindstone, and perform the initial dressing shown in FIG. 10, and currently there is no way to shorten these tact times.

The present invention is provided with an electrode that is arranged opposite to the working surface of a grindstone made of a metal-based bond material with a certain gap, and a voltage is applied through the electrolytic solution filled in the gap. An in-process electrolytic dressing grinding method of grinding a workpiece while performing dressing on the grinding wheel working surface by applying an electrolytic reaction, and using a grindstone having a plurality of grinding wheel working surfaces having different grinding performances. Therefore, it is an object of the present invention to achieve the required processing accuracy and surface roughness with one grindstone in a short tact time, reduce waste of setup time, and improve productivity.

[0008]

In order to achieve the above-mentioned object, the invention according to claim 1 has a grindstone for grinding made of a metal-based bond material and a gap between the working surface of the grindstone. In-process electrolytic dressing grinding in which the workpiece is ground while the facing electrode is provided and the gap is filled with an electrolytic solution and a voltage is applied between the grinding stone and the electrode to perform dressing on the working surface of the grinding stone by electrolytic reaction. In the processing method, as the grindstone, a grindstone in which a plurality of grindstone working surfaces having mutually different grinding performances are arranged in a pick feed direction is used, and grinding is performed while moving each grindstone working surface with respect to a workpiece. It is characterized by doing.

According to a second aspect of the present invention, in the first aspect, a grindstone is used in which the grain size of the abrasive grains forming the grindstone working surface is different for each grindstone working surface. The invention according to claim 3 is the same as that of claim 1
The bonding material forming the grindstone working surface uses a grindstone which is different for each grindstone working surface, and the invention according to claim 4 provides the grindstone working surface according to claim 1. It is characterized by using a grindstone in which the density of the abrasive grains forming the grindstone is different for each grindstone working surface, and the invention according to claim 5 sets the grinding performance in claim 1. As a means to do, corresponding to each grinding wheel working surface,
This is characterized in that the electrolytic dressing action condition in the grinding state is uniquely set.

According to a sixth aspect of the invention, in the fifth aspect, as means for setting the electrolytic dressing action condition,
It is characterized in that the gap between the grindstone and the electrode is uniquely set corresponding to each grindstone working surface, and the invention according to claim 7 is the means for setting the electrolytic dressing working condition in claim 5. As a function of the working surface of each whetstone,
The working area of the electrode with respect to the grindstone is uniquely set, and the invention according to claim 8 is the invention according to claim 5.
In the above, as a means for setting the electrolytic dressing working condition, the strength of the electrolytic reaction is set uniquely corresponding to each grindstone working surface.

According to a ninth aspect of the present invention, in the first aspect, a grindstone in which each grindstone working surface is integrally formed on a single grindstone base is used. According to a tenth aspect of the present invention, in the first aspect, a grindstone in which a plurality of grindstones having different grinding performances are combined to form each whetstone working surface is used.

[0012]

1 is a diagram showing a structural example of a grindstone according to the invention described in claim 2, FIG. 2 is a diagram showing a processing step of a workpiece by the grindstone of FIG. 1, and FIG. 2A is a plan view and FIG. 2B is a front view. In FIG. 1, grindstone
Reference numeral 30 is a straight grindstone, and the width W of the grindstone working surface of the grindstone 30 in the pick feed direction with respect to the workpiece (area of the grindstone working surface) W is divided into two regions W1 and W2, and the grindstone working surface of region W1 31 and the whetstone working surface 32 of the region W2 are different in the grain size of the abrasive grains. For example, the abrasive grains 12a in the region W1 have a grain size of # 140 and the abrasive grains 12b in the region W2 are used.
Uses a grain size of # 600. In this embodiment, the areas W1 and W2 have the same width.

As shown in FIG. 2, when the workpiece is machined, the grindstone 30 is rotated and reciprocally moved in the feed path X direction with respect to the workpiece 22 in the same manner as in FIG. Regarding the pick feed path Y, initially, the processing area 22A of the workpiece 22 is processed by the feed Y1 along the area W1 of the grindstone 30, and the processing area 22F is processed by the feed Y6 through the feeds Y2 to Y5. Then, when the feed by the grindstone 30 is advanced to the state of FIG. 2A, the processing in the processing area 22A is completed in each of the areas W1 and W2. During the processing at that time, the processing area 22B has been processed by the area W1 and the processing area 22C has not yet been processed by the areas W1 and W2. When the area W2 faces the processing area 22F and the processing is completed, the workpiece 22 is completely processed by the areas W1 and W2.

In this way, one grindstone 30 can be machined to the required machining accuracy and surface roughness. And since a plurality of grindings are performed in parallel in the process of moving the grindstone 30 in one direction, the grinding work is achieved in a short takt time,
In addition, waste of setup time can be reduced and productivity is improved. 3A and 3B are views showing another example of the construction of the grindstone according to the invention of claim 2, wherein FIG. 3A is a front view and FIG. 3B is a sectional view.

In FIG. 3, 40 is a grindstone for honing. In the grindstone 40, the height W of the grindstone working surface (area of the grindstone working surface) W is divided into a region W1 and a region W2, and a region W1
The whetstone working surface 41 and the whetstone working surface 42 of the region W2 have different grain sizes. For example, abrasive grains (not shown) in the region W1 have a grain size of # 140, and abrasive grains (not shown) in the region W2 have a grain size of # 600. 43 is an electrode, 44 is an electrolytic solution supply unit, and 45 is a workpiece. The grindstone 40 is moved up and down in the figure while rotating to be ground. Also in this case, the same effect as in FIGS. 1 and 2 can be obtained.

In the embodiment shown in FIGS. 1 and 3, each region W
Although 1 and W2 are clearly separated by using abrasive grains having different grain sizes, abrasive grains having different grain sizes may be mixed and the mixture ratio may be sequentially changed in each of the regions W1 and W2. Each area W
The mixing ratio may be changed for each 1 and W2. FIG. 4 is a diagram showing a configuration example of a grindstone according to the invention of claim 3.

In FIG. 4, reference numeral 50 is a grindstone for cutting optical glass. The whetstone 50 has a whetstone outer peripheral portion 51 made of a cobalt-based bond material, and a whetstone side surface portion 52 made of an iron-based bond material. 53 is a workpiece. Currently ELI
Examples of the bond material for the grinding wheel for D grinding include iron-based fiber, iron-based, cobalt-based, and bronze-based. These differ in the presence or absence of non-conductive coating and the magnitude of electrolysis rate,
Along with this, since the abrasion of the abrasive grains and the roughness of the finished surface are also different, for example, iron-based fibers and iron-based materials are used for the mirror surface, and cobalt-based and bronze-based materials are used for the efficiency. In the configuration of FIG. 4, when the optical glass is cut as the workpiece 53, the cutting work is required to have high efficiency, but the surface roughness of the cut surface is required to be good. The grindstone 50 is moved up and down in the figure while rotating to process the workpiece 53. The cutting is performed at the grindstone outer peripheral portion 51, so that the cutting is performed at high speed. Then, the grinding of the cut surface is performed on the side surface 52 of the grindstone to obtain a good surface roughness. Further, the productivity is improved as in FIGS. 1 and 2.

In the fourth aspect of the invention, the grindstone working surface 31 and the grindstone working surface 32 in FIG. 1 have different grain sizes of abrasive grains, but instead of this, a grindstone working surface is formed. It is realized by using a whetstone in which the grain sizes of the whetstones are the same and the density of the whetstone is different for each whetstone working surface. If the density is large even if the particle size is the same, for example, in the case of a straight grindstone, the removal amount per abrasive grain becomes small in the rotating direction of the grindstone, and the cutting edge profile becomes finer in the width direction. A finished surface having a better surface roughness can be obtained. In the example shown in FIG. 1, by constructing a straight grindstone with two working surfaces having different densities in the width direction, the dividing step of rough machining → intermediate finishing or intermediate finishing → final finishing can be performed by one grindstone in one step. realizable. In this way, the same effect as in FIGS. 1 and 2 can be obtained. Moreover, since the number of dividing steps is increased by increasing the number of working surfaces by combining these,
The required accuracy can be more appropriately dealt with.

FIG. 5 is a diagram showing another example of the construction of the grindstone according to the present invention. FIG. 5A is a diagram showing the initial dressing state of the working surface of the grindstone during rough machining. (B) is a diagram showing an initial dressing state of the grindstone working surface at the time of intermediate finishing. In FIG. 5, the grindstone 60 is similar to the grindstone 30 in FIG. The grindstone 60 performs the initial dressing of the grindstone working surface 32 of the area W2 at a higher strength than the grindstone working surface 31 of the area W1 at the time of roughing, and the initial dressing of the grindstone working surface 31 of the area W1 at the time of intermediate finishing. It is stronger than the grinding wheel working surface 32. Therefore, at the time of rough processing, only the grindstone working surface 31 having a small grain size is involved in the processing.
Then, during the medium processing, only the grindstone working surface 32 of high grain size is involved in the processing. In this way, productivity is improved by shifting the time and using a plurality of different grinding wheel working surfaces properly.

According to a fifth aspect of the present invention, in the in-process electrolytic dressing grinding method according to the first aspect, the electrolytic dressing working condition is set uniquely corresponding to each grindstone working surface in the grinding working state. There is. FIG. 6 is a diagram showing a configuration example of a grindstone according to the invention of claim 6 for setting an electrolytic dressing working condition.

In FIG. 6, a grindstone 30 is the grindstone in FIG.
Similar to 30. As a means for setting the electrolytic dressing action condition, the electrode 21A is provided in the region W1 with respect to the grindstone 30.
The gap d1 with the region W2 is made smaller than the gap d2 with the region W2 to increase the electrolytic strength of the region W1 so that the dressing surface 31 of the region W1 is dressed with a stronger strength than the dressing surface 32 of the region W2. The film is made thick. Therefore, the same effect as in FIGS. 1 and 2 can be obtained.

According to a seventh aspect of the present invention, as a means for setting the electrolytic dressing action condition, the facing area of the electrode 21A with respect to the grindstone action surfaces 31, 32 is changed.
Also in this case, the same effect as in FIG. 6 can be obtained. According to the invention of claim 8, as a means for setting the electrolytic dressing working condition, the applied voltage between the grindstone 30 and the electrodes is made to correspond to the grindstone working surfaces 31, 32, and the strength of the electrolytic reaction is uniquely set. Yes, the required electric circuit is configured so that the applied voltage can be adjusted. It should be noted that the grindstone working surfaces 31, 32 must be insulated from each other. Also in this case, the same effect as in FIG. 6 can be obtained.

The invention according to claim 9 is characterized in that, instead of the grindstone in claim 1, a grindstone in which each grindstone working surface is integrally formed on a single grindstone base is used. FIG. 7 is a diagram showing a structural example of a grindstone according to the invention of claim 9. In FIG. 9, a grindstone 70 is a straight grindstone and is formed by brazing individual grindstone layers 72 and 73 on a single base metal 71 so as to correspond to the regions W1 and W2. By using this grindstone 70, the same effect as in FIGS. 1 and 2 can be obtained.

According to a tenth aspect of the present invention, instead of the grindstone of the first aspect, a grindstone in which a plurality of grindstones having different grinding performances are combined to form each whetstone working surface is used. FIG. 8 is a diagram showing a configuration example of a grindstone according to the invention of claim 10. In FIG.
The grindstone 80 includes a grindstone 81 having a grindstone working surface 81A in a region W1,
The grindstone 82 having the grindstone working surface 82A in the region W2 is coaxially assembled by the main shaft 83. The grindstone working surfaces 81A and 82A have different grain sizes from each other, as in FIG.
By using this grindstone 80, the same effect as in FIGS. 1 and 3 can be obtained.

[0025]

According to the inventions of claim 1, claim 2, claim 3, claim 4, claim 9 and claim 10, a plurality of grinding wheel working surfaces having different grinding performances are provided. By using the provided grindstone, it was possible to move each grindstone working surface with respect to the work piece along with the grinding process, so by setting the grinding performance of each grinding working surface appropriately, the required working accuracy The surface roughness can be processed with one grindstone in a short tact time, and waste of setup time can be reduced to improve productivity.

Claims 5, Claim 6, Claim 7, Claim 8
According to the invention described above, as the means for setting the grinding performance in claim 1, the electrolytic dressing working condition in the grinding processing state is set uniquely corresponding to each grindstone working surface, so that each electrolytic dressing working condition is set appropriately. By setting to 1, the required processing accuracy and surface roughness can be achieved with one grindstone in a short takt time, and the waste of setup time can be reduced to improve the productivity.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration example of a grindstone according to a second aspect of the invention.

FIG. 2 is a diagram showing a processing step of a workpiece with the grindstone of FIG.

FIG. 3 is a diagram showing another configuration example of the grindstone according to the invention of claim 2.

FIG. 4 is a diagram showing a configuration example of a grindstone according to the invention of claim 3;

FIG. 5 is a diagram showing another configuration example of the grindstone according to the invention of claim 2;

FIG. 6 is a diagram showing a configuration example of a grindstone according to the invention of claim 6;

FIG. 7 is a diagram showing a configuration example of a grindstone according to the invention of claim 9;

FIG. 8 is a diagram showing a configuration example of a grindstone according to the invention of claim 10;

FIG. 9 is a principle diagram of an ELID grinding method.

FIG. 10 is a schematic diagram showing a mechanism of an ELID grinding method.

FIG. 11 is a view showing an arrangement example of abrasive grains.

FIG. 12 is a current characteristic diagram with respect to progress of ELID grinding.

[Explanation of symbols]

 10, 30, 40, 50, 60, 70, 80, 81, 82 Grindstone 11 Bond material 12, 12a, 12b Abrasive grain 21, 21A, 43 Electrode 22, 45, 53 Work piece 23, 44 Electrolyte supply part 31 , 32, 81A, 82A Grinding wheel working surface 22A, 22B, 22C, 22D, 22E, 22F Machining area 41, 42 Grinding wheel working surface 51 Grinding wheel outer periphery 52 Grinding wheel side surface 71 Base metal 72, 73 Grinding wheel layer 83 Spindle W Grinding wheel working surface Width (area of grinding wheel working surface) W1, W2 area

Claims (10)

[Claims] 1. A grindstone made of a metal-based bond material for grinding, and an electrode disposed opposite to a working surface of the grindstone with a gap, and the gap is filled with an electrolytic solution. And an in-process electrolytic dressing grinding method for grinding a workpiece while performing dressing on the working surface of the grindstone by applying a voltage between the electrodes, as the grindstone, a plurality of grindstones having different grinding performances from each other. An in-process electrolytic dressing grinding method characterized in that a grindstone having working surfaces arranged in a pick feed direction is used to perform grinding while moving each working surface of each grindstone on a workpiece. 2. The in-process electrolytic dressing grinding method according to claim 1, wherein a grindstone having different grain sizes of the abrasive grains forming the grindstone working surface is used for each grindstone working surface. 3. The in-process electrolytic dressing grinding method according to claim 1, wherein a grindstone in which the bond material forming the grindstone working surface is different for each grindstone working surface is used. 4. The in-process electrolytic dressing grinding method according to claim 1, wherein a grindstone in which the density of the abrasive grains forming the grindstone working surface is different for each grindstone working surface is used. 5. The in-process electrolytic dressing grinding according to claim 1, wherein as a means for setting the grinding performance, the electrolytic dressing working condition in the grinding processing state is set uniquely corresponding to each grinding wheel working surface. Processing method. 6. The in-process electrolytic dressing grinding according to claim 5, wherein a gap between the grindstone and the electrode is uniquely set corresponding to each grindstone working surface as means for setting the electrolytic dressing working condition. Processing method. 7. The means for setting the electrolytic dressing working condition is that the working area of the electrode for the grindstone is set uniquely corresponding to each grindstone working surface.
In-process electrolytic dressing grinding method described. 8. The in-process electrolytic dressing grinding method according to claim 5, wherein, as means for setting the electrolytic dressing working condition, the strength of the electrolytic reaction is set uniquely corresponding to each grinding stone working surface. . 9. The in-process electrolytic dressing grinding method according to claim 1, wherein a grindstone in which each grindstone working surface is integrally formed on a single grindstone base is used. 10. The in-process electrolytic dressing grinding method according to claim 1, wherein a grindstone in which a plurality of grindstones having different grinding performances are combined to form each grindstone working surface is used.