JPH0771788B2 - Whetstone - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial field of application" The present invention relates to a metal bond grindstone, a resinoid bond grindstone,
The present invention relates to a whetstone such as an electrodeposition whetstone and an electroformed whetstone.

"Prior art" This type of grindstone uses super-abrasive grains such as diamond and CBN with thermosetting resin (in the case of resinoid bond grindstone) or metal (in the case of metal bond grindstone, electrodeposition grindstone, electrocast grindstone) It has an abrasive grain layer dispersed in the formed binder phase.

[Problems to be Solved by the Invention] In such a grindstone, since the binder phase is densely formed, the friction coefficient between the surface of the binder phase and the material to be ground is large and the grinding resistance is large. Is big. Therefore, there is a problem that a large driving force is required during grinding and the grindstone is easily overheated due to frictional heat generated during grinding.

Further, in such a grindstone, since the superabrasive grains are firmly held by the dense binder phase, it is difficult for the superabrasive grains to fall off, and the protrusion of the superabrasive grains that should be newly involved in grinding is slow, so-called There is also a problem that the self-sharpening action of superabrasive grains is insufficient, and at the same time, chip pockets are hard to form on the surface of the grindstone, resulting in poor chip discharge and cooling performance with cooling water.

On the other hand, as a means for reducing the grinding resistance, lubricating particles such as fluororesin are added to the binder phase, and these lubricating particles are exposed from the surface of the binder phase to form a binder phase surface and a material to be ground. Although it is considered to reduce the friction resistance of, in practice, it is difficult to uniformly disperse the lubricating particles having a relatively small specific gravity and the superabrasive grains having a large specific gravity in the binder, Lubricating particles are likely to be unevenly distributed in the abrasive grain layer, which causes new defects such as deterioration in sharpness of the grindstone, local abnormal wear, and reduction in strength of the abrasive grain layer.

"Object of the Present Invention" An object of the present invention is to provide a grindstone having a small grinding resistance, a good sharpness, and a good chip discharge property.

"Means for solving the problem" The grindstone according to the present invention, a plurality of lubricating particles having an average particle diameter of 1/100 to 2/3 of the average particle diameter of the superabrasive particles are arranged around the superabrasive particles. Then, the complex abrasive grains having a complicated shape in which a plurality of protrusions are formed on the outer periphery of the superabrasive grains and the lubricative particles are adhered to each other by a metal coating that surrounds the outer periphery of the abrasive grains in the binder phase. A grindstone having an abrasive grain layer dispersed therein, wherein the metal coating is a first metal layer formed directly on the outer periphery of the superabrasive grain, and a second metal layer formed directly on the outer periphery of the lubricating particle. , And the first metal layer and the second metal layer
It is characterized in that it is formed of a third metal layer for joining the metal layers.

[Examples] Examples of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is an enlarged sectional view showing a grindstone (electroplated grindstone) according to an embodiment of the present invention.

In the figure, reference numeral 1 is a whetstone base metal, and on the whetstone base metal 1,
An abrasive grain layer 4 formed by dispersing composite abrasive grains 3 in a metal plating phase (binder phase) 2 is formed. Further, pores 5 are partially formed inside the abrasive grain layer 4.

As shown in FIG. 2, the composite abrasive grain 3 is formed by fixing a large number of lubricating particles 7 ... To the surface of a superabrasive grain 6 such as diamond or CBN via a metal coating 8.

As the material of the lubricating particles 7, hexagonal boron nitride, molybdenum disulfide, graphite fluoride, fluororesin such as tetrafluoroethylene, etc. are suitable. The average particle size of the lubricating particles 7 is preferably 1/100 to 2/3 of the average particle size of the superabrasive particles 6. This average grain size is 1/100 of the average grain size of superabrasive grains
If it is less than the above range, a sufficient grinding resistance lowering effect cannot be obtained. On the other hand, if it is more than 2/3 of the average particle size of the superabrasive grains, the biting of the superabrasive grains 6 into the material to be ground may be deteriorated. The ratio of the lubricious particles 7 to the entire abrasive grain layer 4 is 2 to 30 vol.
% Is desirable, and if it is less than 2 vol%, a sufficient grinding resistance lowering effect cannot be obtained, and conversely, the proportion of the lubricating particles 7 ...
If it is more than 30 vol%, the sharpness and strength of the grindstone may decrease.

The metal coating 8 has a metal layer (first metal layer) 8a having a hard magnetic property directly formed on the surface of the superabrasive grain 6 and a hard magnetic property directly formed on the surface of the lubricating particles 7. It comprises a metal layer (second metal layer) 8b that it has, and a bonding layer (third metal layer) 8c that bonds these metal layers 8a, 8b.
As a material for the metal layers 8a and 8b, Ni, Co, Fe or the like is suitable. The material of the bonding layer 8c is Ni, Fe, Cu, Cr, C.
O, Zn, Sn and the like are preferable in terms of cost. The thickness of the metal coating 8 including them together is preferably 0.5 μm or more. If the thickness is less than 0.5 μm, the force for adhering the lubricating particles 7 to the surface of the superabrasive grains 6 becomes weak and the composite abrasive Grain 3 becomes fragile.

The proportion of the pores 5 in the abrasive grain layer 4 is 5 to 60 vol.
% Is desirable. If the proportion of pores 5 is less than 5 vol%, the chip pocket formation effect will be reduced, resulting in 60 vol.
If it is larger than%, the force of the metal plating layer 2 holding the composite abrasive grains 3 becomes weak.

Next, a method for manufacturing such an electrodeposition grindstone will be described in the order of steps.

First, a metal layer 8a is formed on the surface of the superabrasive grains 6 by a thin film forming method such as electroless plating or sputtering.
It is formed with a thickness of about a few times. Then, the plated superabrasive grains 6 are applied to a magnetizing device to magnetize the metal layer 8a.

On the other hand, the metal layer 8b is also formed on the surface of the lubricating particles 7 by the same method as described above (not magnetized).

Then, the superabrasive particles 6 and the lubricating particles 7 are sufficiently mixed, the metal layer 8b of the lubricating particles 7 is attracted by the magnetic force of the metal layer 8a of the superabrasive particles 6, and the lubricating particles are provided around the superabrasive particles 6. 7 is attached. Then, this mixed powder is again added to the electroless plating solution to form the bonding layer 8c that encloses these particles 6 and 7, thereby manufacturing the composite abrasive grain 3.

Next, the composite abrasive grain 3 thus formed is added to a plating solution in which ions such as Ni and Co are dissolved. Then, the whetstone base metal 1 is dipped in this plating solution, the whetstone base metal 1 is connected to the cathode of the power source, and the anode is arranged in the plating liquid to form the metal plating phase 2 on the whetstone base metal 1. At the same time, the composite abrasive grains 3 ... Are dispersed in the metal plating phase 2 to form the abrasive grain layer 4. At this time, the metal coating 8 of the composite abrasive grains 3 attached to the metal plating phase 2 is also sequentially metal-plated, so that the gaps between the composite abrasive grains 3 and the composite abrasive grains 3 are partially formed. It remains unfilled, forming pores 5.

In this way, when the abrasive grain layer 4 reaches a predetermined thickness, the energization is stopped and the abrasive grain layer is subjected to a treatment such as dressing to obtain an electrodeposition grindstone.

In the electrodeposition grindstone having such a structure, the lubricating particles 7 are fixed around the individual superabrasive grains 6 to form the composite abrasive grains 3, and then the composite abrasive grains 3 are coated with the metal plating layer. Since the lubricant particles 7 are dispersed in the abrasive grain layer 4, the lubricant particles 7 are not unevenly distributed in the abrasive grain layer 4, and the lubricant particles 7 can always be exposed from the surface of the abrasive grain layer 4 at an appropriate density. Therefore, according to such an electrodeposition grindstone, it is possible to lower the friction coefficient with the material to be ground without causing the lubricating particles 7 ... To protrude from the surface of the abrasive grain layer 4 more than necessary to reduce the sharpness of the grindstone. It is possible to reduce the grinding resistance, reduce frictional heat generated during grinding, and prevent abnormalities such as overheating.

Further, in this electrodeposition grindstone, the metal coating 8 is formed around the superabrasive grains 6.
Since the lubricating particles 7 having a relatively small bonding strength with the are arranged, the metal coating 8 is separated from the interface between the lubricating particles 7 and the metal coating 8 when a large force is applied to the superabrasive grains 6. Then, the superabrasive grains 6 fall off. Therefore, in this electrodeposited grindstone, compared with the conventional electrodeposited grindstone, the superabrasive grain holding force can be appropriately reduced, the self-developing blade action of the superabrasive grains 6 can be promoted, and the sharpness of the grindstone can be improved. In addition to being able to achieve, it is possible to reduce the processing damage that occurs in the material to be ground. At the same time, since the chip pockets are easily formed, the chip discharge performance can be improved, and the effect of retaining the cooling water on the surface of the abrasive grain layer 4 can be enhanced to improve the cooling efficiency of the grindstone. Further, in this electrodeposited grindstone, the pores 5 are partially formed in the abrasive grain layer 4 and the abrasive grain layer 4 has a porous structure, so that the above-mentioned effects are more remarkable. .

Furthermore, in the composite abrasive grain 3 used in this grindstone, the super-abrasive grain 6 covered with the metal layer 8a is provided with the lubricating particles 7 coated with the metal layer 8b, and the two are bonded together. Since the structure is fixed by the layer 8c, the surface of the composite abrasive grain 3 becomes a metal surface over the entire surface. In addition, since a large number of protrusions made of the metal coating 8 wrapping the lubricating particles 7 are formed on the outer peripheral surface of the composite abrasive grain 3, not only can a large bonding area with the binder phase 2 be secured, but also these protrusions can be formed. A strong anchoring effect can be obtained by deeply digging into the binder phase 2. As described above, the entire outer peripheral surface of the composite abrasive grain 3 is a metal surface, the surface area per volume is large, and the anchor effect is obtained, whereby the holding force of the composite abrasive grain 3 by the binder phase 2 is increased. Since it becomes extremely large, when the composite abrasive grain 3 is exposed on the polishing surface, the whole composite abrasive grain 3 does not fall off from the binder phase 2, and the superabrasive grain 6 is wastefully lost before being used for grinding. It also has the advantage of being rarely exposed.

In the above-mentioned embodiment, the abrasive grain layer 4 is the composite abrasive grain 3
However, the present invention is not limited to this, and the composite abrasive grains 3 and superabrasive grains that are not composite abrasive grains may be mixed and dispersed in the abrasive grain layer. .

"Experimental Example" Next, the effect of the present invention will be demonstrated by giving an experimental example of the present invention.

(Example 1) Diamond superabrasive grain powder (200 to 240 mesh) was immersed in an aqueous palladium salt solution to impart catalytic activity to the surface of the superabrasive grains.

This super-abrasive powder is electroless cobalt plating solution (cobalt sulfate: 25 g /, sodium succinate: 25 g /, sodium sulfate: 15 g /, dimethylamine borane: 2 g /, PH: 5.
(0, liquid temperature: 70 ° C.) to form a cobalt coating layer of about 3 μm on the surface of the superabrasive grains.

The cobalt-coated superabrasive powder was enclosed in a plastic bottle and exposed to a magnetic field of 5 kilo Oersted for magnetization.

Separately, hexagonal boron nitride (hBN) powder (average particle size 1 to 5 μm) was subjected to the same treatment as described above to form a cobalt coating of about 2 μm on the surface.

Superabrasive grains 100g and hBN powder 20g that have been subjected to the above treatment are sealed in a plastic bottle, mixed sufficiently, and by the magnetic force of the cobalt coating on the surface of the superabrasive grains, a plurality of hBN particles are provided around the superabrasive grains. Attached.

This mixed powder was again immersed in the aqueous solution of palladium salt to impart catalytic activity to the surface of the mixed powder.

Next, this mixed powder was dispersed in an electroless copper plating solution (OPC Copper S manufactured by Okuno Chemical Industries Co., Ltd., liquid temperature: 50 ° C.) to obtain composite abrasive grains having a copper coating of 5 μm formed on the surface.

The composite abrasive grains (average particle size) produced in this way were added to the resin binder powder (phenol resin) at 30 vol%, mixed well, fixed in the mold and fixed on the whetstone base, then hot pressed and fired. Then, the disc was shaped into a grindstone to obtain a discoid resinoid bond grinding wheel.

(Comparative Example 1) Diamond superabrasive grains (200 to 240 mesh) were used in Experimental Example 1
After adding 20vol% to the same resin binder powder as above, mixing well, fixing it on the grinding stone base metal, hot pressing and sintering, shaping into a grinding stone shape, the same shape as the experimental example I got a resinoid bond grindstone.

Then, the two resinoid bond grindstones were used to perform grinding under the following grinding conditions (wet).

Grinding conditions Grinding material: 96% alumina material Grinding wheel peripheral speed: 1500 m / min. Feed rate: 10 m / min. Cross feed: 2 mm Depth of cut: 0.01 mm Table 1 shows the grinding results of the two resinoid bond grinding wheels. is there.

As is clear from the above table, the grinding resistance was reduced in the resinoid bond grindstone of the experimental example.

(Experimental Example 2) Next, an electroformed thin blade grindstone to which the present invention was applied was prepared and compared with a conventional electroformed thin blade grindstone.

FIG. 3 is a vertical sectional view of the manufacturing apparatus used at that time. Reference numeral 10 is a plating tank, and in the plating tank 10,
The plating solution M containing Ni ions is filled. Further, the plating tank 10 is provided with a stirrer such as an ultrasonic stirrer not shown. The plating tank 10 has a non-conductive base.
11 are arranged horizontally, and a flat substrate 12 made of stainless steel is placed on the pedestal 11. This flat board 12
Is masked on the upper surface of the whetstone, leaving a portion forming the prototype shape of the grindstone to be manufactured. Further, an anode plate 13 is arranged above the plane substrate 12 in parallel with the plane substrate 12 and connected to an anode of a power source (not shown).

In manufacturing the electroformed thin blade grindstone, first, in the plating solution M in the plating tank 10, a composite abrasive grain in which 2 μm hBN particles were arranged on the surface of 25 μm diamond superabrasive grains was prepared in the same manner as in Experimental Example 1. A fixed amount was added and uniformly dispersed in the plating solution M by a stirrer. Next, the flat substrate 12 is connected to the cathode of the power source, and an electric current is applied between the flat substrate 12 and the anode plate 13 to form the Ni plating phase 14 on the surface of the flat substrate 12 and uniformly mix the composite abrasive grains in the Ni plating phase 14. It was dispersed and incorporated.

Then, when the metal plating phase 14 reached a predetermined thickness, the power supply was stopped, the flat substrate 12 was taken out of the plating tank 10 and washed with water. Then, the metal plating phase 14 was peeled from the flat substrate 12, subjected to lapping and peripheral polishing, and shaped into a predetermined shape to obtain an electroformed thin blade grindstone.

(Comparative Example 2) By the same method as in Experimental Example 2, an electroformed thin blade grindstone of Comparative Example 2 was prepared by using superabrasive grains instead of the composite abrasive grains.

Then, using the grinding stones of Experimental Example 2 and Comparative Example 2,
Grinding was performed under the following grinding conditions.

Grinding conditions Grinding material: Ferrite Grinding wheel peripheral speed: 1500 m / min. Feed rate: 100 mm / min. Depth of cut: 2.0 mm Table 2 shows the results of grinding by these electroformed thin blade grindstones.

As shown in Table 2, the electroformed thin blade grindstone of Experimental Example 2 was able to reduce the grinding resistance and chipping as compared with the grindstone of Comparative Example 2.

"Effects of the Invention" According to the grindstone of the present invention, the following excellent effects can be obtained.

Lubrication is performed in the abrasive grain layer because lubricant particles are fixed around each superabrasive grain to form a composite abrasive grain, and then this composite abrasive grain is dispersed in the metal plating phase to form an abrasive grain layer. It is possible to always expose the lubricating particles from the surface of the abrasive grain layer at an appropriate density without uneven distribution of the functional particles. Therefore,
According to such an electrodeposition grindstone, without lowering the sharpness of the grindstone by protruding the lubricating particles from the surface of the abrasive grain layer more than necessary, the friction coefficient with the material to be ground is reduced, and the grinding resistance is reduced. At the same time, the frictional heat generated during grinding can be reduced to prevent the grindstone from overheating.

Lubricating particles with relatively low bonding strength with the metal coating are placed around the superabrasive particles, so if a large force is applied to the superabrasive particles, the metal from the interface between the lubricating particles and the metal comparison will be used. The coating peels off and the superabrasive grains fall off. Therefore, in this electrodeposited grindstone, compared to the conventional electrodeposited grindstone, it is possible to moderately reduce the superabrasive grain holding force, and by promoting the spontaneous blade action of the superabrasive grains, it is possible to improve the sharpness of the grindstone. ,
It is possible to reduce processing damage that occurs in the material to be ground. At the same time, since the chip pockets are easily formed, the chip discharge performance can be improved, and the effect of retaining the cooling water on the surface of the abrasive grain layer can be enhanced to improve the cooling efficiency of the grindstone.

The composite abrasive grains used in the grindstone of the present invention is such that the superabrasive grains covered with the first metal layer are provided with lubricious particles coated with the second metal layer, and both are treated with the third metal. Since the structure is fixed in layers, the surface of the composite abrasive grain becomes a metal surface over the entire surface. In addition, since a large number of protrusions made of a metal coating that wraps the lubricating particles are formed on the outer peripheral surface of the composite abrasive grain, not only can a wide bonding area with the binder phase be secured, but these protrusions can also form a binder phase. A strong anchor effect can be obtained by cutting deeply. In this way, the entire outer peripheral surface of the composite abrasive grain is a metal surface, the surface area per volume is large,
Also, since the anchoring effect of the composite abrasive grains by the binder phase is increased by obtaining the anchor effect, the entire composite abrasive grains do not fall out of the binder phase when the composite abrasive grains are exposed on the polishing surface. . Therefore, not only is the superabrasive grain rarely lost in vain before being used for grinding, but also the heat dissipation effect of dispersing the heat generated by the superabrasive grain due to the metal coating, the effect of promoting spontaneous blade generation, and the polishing It is possible to ensure the lubricating effect of reducing the frictional resistance between the surface and the work material.

[Brief description of drawings]

FIG. 1 is a partially enlarged cross-sectional view of an electrodeposition grindstone according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of a composite abrasive grain of the grindstone, and FIG. 3 is for manufacturing a grindstone of an experimental example of the present invention. It is a longitudinal cross-sectional view of a manufacturing apparatus. 1 ... Whetstone base metal, 2 ... Metal plating phase (binder phase) 3 ... Composite abrasive grains, 4 ... Abrasive grain layer, 5 ... Porosity, 6 ... Super abrasive grain, 7 ... Lubricating particles , 8 ... metal coating, 8a ... first metal layer, 8b ... second metal layer, 8c ... joining layer (third metal layer).

Claims (3)

[Claims] 1. Around 1/10 of the average grain size of the superabrasive grains around the superabrasive grains.
A plurality of lubricating particles having an average particle size of 0 to 2/3 are arranged, and the superabrasive particles and a plurality of lubricating particles are adhered to each other by a metal coating surrounding the entire outer circumference of the lubricating particles. Complex shaped abrasive grains with protrusions formed,
A grindstone having an abrasive grain layer dispersed in a binder phase,
The metal coating is a first metal layer formed directly on the outer periphery of the superabrasive grains, and a second metal layer formed directly on the outer periphery of the lubricating particles.
A grindstone formed of a metal layer and a third metal layer for joining the first metal layer and the second metal layer. 2. The grindstone according to claim 1, wherein the content of the lubricating particles in the abrasive grain layer is 2 to 30 vol%. 3. The grindstone according to claim 1 or 2, wherein the abrasive grain layer has pores of 5 to 60 vol%.