JPS6334069A - Grindstone - Google Patents

Abstract

PURPOSE:To obtain the superior cutting performance and discharge performance by forming an abrasive grain layer by dispersing the composite abrasive grains which are formed by fixing a lubricating particle onto a superfine abrasive grain through metal covering, into a bonding agent phase. CONSTITUTION:A metal layer 8a is formed onto the surface of a superfine abrasive grain 6 by the thin film formation method through plating, sputtering, etc., and magnetized. Also a metal layer 8b is formed onto the surface of the lubricating particle 7 having an average particle diameter in 1/100-2/3 of the average diameter of the superfine abrasive grain. Then, the superfine abrasive grains 6 and the lubricating particles 7 are sufficiently mixed, and the metal layer 8 is adsorbed by the magnetic force of the metal layer 8a, and after the lubricating particle 7 is allowed to adhere onto the periphery of the superfine abrasive grain, a composite abrasive grain 3 having a joint layer 8c is manufactured through the electroless plating method. The composite abrasive grains 3 are added into the plating liquid into which the ions such as Ni and Co are dissolved, and a grindstone base metal 1 is immersed, and an abrasive grain layer 4 is formed. Therefore, the grinding resistance can be reduced, and the cutting performance can be improved, and the performance in discharging chips can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention is applicable to metal bond grindstones, resinoid bond grindstones,
It relates to grindstones such as electroplated grindstones and electroformed grindstones.

"Conventional technology" This type of grindstone uses super abrasive grains such as diamond and CBS.
It has a layer of abrasive particles dispersed in a binder phase made of thermosetting resin (in the case of resinoid bonded grindstones) or metal (in the case of metal bonded grindstones, electroplated grindstones, and electroformed grindstones).

``Problems to be Solved by the Invention'' By the way, in such a grindstone, since the bonding agent is densely formed, the coefficient of friction between the rough surface of the bonding agent and the material to be ground is large, which reduces the grinding resistance. is large. For this reason, there is a problem in that a large driving force is required during grinding, and the grindstone is likely to overheat due to frictional heat generated during grinding.

In addition, in such grinding wheels, the superabrasive grains are firmly held by the dense binder, so the superabrasive grains do not fall off.
, the protrusion of the superabrasive grains that are newly involved in grinding is slow, and the so-called self-generating full-edge action of the superabrasive grains is insufficient. At the same time, chip pockets are difficult to form on the grinding wheel surface, resulting in poor chip evacuation and There was also the problem that the cooling performance of the cooling water was poor.

On the other hand, as a means to reduce the grinding resistance, lubricating particles such as fluororesin are added to the binder phase, and these lubricating particles are exposed from the rough surface of the binder, thereby forming a bond between the rough surface of the binder and the material to be ground. It is thought that it reduces frictional resistance, but
In reality, it is difficult to uniformly disperse lubricating particles, which have a relatively small specific gravity, and superabrasive particles, which have a large specific gravity, in a binder, and the lubricating particles tend to be unevenly distributed in the abrasive layer. New drawbacks arise, such as a decrease in the sharpness of the grindstone, abnormal local wear, and a decrease in the strength of the abrasive fi layer.

"Objective of the Present Invention" An object of the present invention is to provide a grindstone with low grinding resistance, good sharpness, and good chip evacuation.

"Means for Solving the Problems" The grinding wheel of the present invention has superabrasive grains with a diameter of 1/100 of the average particle diameter of the superabrasive grains.
It is characterized by growing an abrasive grain layer in which lubricating particles having an average particle diameter of ~2/3 are fixed by a metal coating and dispersed in a binder.

"Example" Embodiments of the present invention will be described in detail below 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.

The symbol l in the figure is a grinding wheel base metal, and on this grinding wheel alloy 1,
An abrasive grain layer 4 is formed by dispersing abrasive grains 3 in a metal plating phase (binder phase) 2.

Furthermore, pores 5 are partially formed inside this abrasive grain layer 4.

As shown in FIG. 2, the abrasive grains 3 have a large number of lubricating particles 7 on the surface of superabrasive grains 6 such as diamond or CBN.
... are fixed through a metal coating 8.

Suitable materials for the lubricating particles 7 include hexagonal boron nitride, molybdenum disulfide, graphite fluoride, and fluororesins such as tetrafluoroethylene. In addition, the average particle size of the lubricating particles 7 is 1/100 to 2/2 of the average particle size of ultra-low #i6.
3 is desirable. If this average grain size is less than 1/100 of the average grain size of the superabrasive grains, a sufficient grinding resistance reduction effect cannot be obtained, while on the other hand, if it is larger than 2/3 of the average grain size of the superabrasive grains, There is a risk that the superabrasive grains 6 may become less likely to bite into the surface. The proportion of the lubricating particles 7 in the entire abrasive layer 4 is desirably 2 to 30 vol%;
If the vo is less than 1%, a sufficient grinding resistance reduction effect cannot be obtained,
On the other hand, if the proportion of the lubricating particles 7 is greater than 30vol%, the sharpness and strength of the grindstone may be reduced.

The metal coating 8 includes a metal layer 8a having hard magnetic properties formed directly on the surface of the superabrasive grains 6, and a metal layer 8b having hard magnetic properties formed directly on the surface of the lubricant particles 7.
and a bonding layer 8 that bonds these metal layers 8a and 8b.
It is composed of c. The metal layers 8a, 8b
Suitable materials include Ni, Co, Fe, etc. Further, the material of the bonding layer 8c includes Ni, Fe,
Cu, Cr, Co, Zn, Sn, etc. are preferable from the viewpoint of cost. The thickness of the metal coating 8 that combines these is 0.
, 5 μm or more is desirable. If the particle size 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 grains 3 become easily broken.

The proportion of the pores 5 in the abrasive grain layer 4 is 5 to 60.
It is desirable that it be vo1%. The proportion of stomata 5.
If it is less than 1%, the chip pocket formation effect will be small, and if it is more than 60 vo1%, the metal plating layer 2
The force holding the abrasive grains 3 becomes weaker.

Next, a method for manufacturing such an electrodeposited grindstone will be explained step by step.

First, a metal layer 8a is formed on the surface of the superabrasive grains 6 using a thin film forming method such as an electroless plating method or a sputtering method to have a thickness that is a fraction of the thickness of the metal coating 8.

Then, the plated superabrasive grains 6 are applied to a magnetizing device to magnetize the metal layer 8a.

On the other hand, a metal layer 8b is also formed on the surface of the lubricant particles 7 using the same method as described above (without magnetization).

Next, the superabrasive grains 6 and the lubricant particles 7 are sufficiently mixed, and the metal layer 8 of the lubricant particles 7 is mixed with the magnetic force of the metal layer 8a of the superabrasive grains 6.
b, and the lubricating particles 7 are attached around the superabrasive grains 6. Then, this mixed powder is added to the electroless plating solution again to form a bonding layer 8c that envelops these particles 6.7, thereby producing composite abrasive grains 3.

Next, the composite paper fL3 made in this way was coated with Ni and C.

ion is added to the plating solution containing dissolved ions. Then, the grinding wheel base metal 1 is immersed in this plating solution, and this grinding wheel base metal 1 is connected to the cathode of the power source, and an anode is placed in the plating solution to form a metal plating phase 2 on the grinding wheel base metal l. At the same time, composite abrasive grains 3 are dispersed in this metal plating phase 2 to form an 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 plated with metal, so that the gaps between the composite abrasive grains 3 are partially The pores remain unfilled and pores 5 are formed.

In this manner, when the abrasive grain layer 4 reaches a predetermined thickness, the electricity supply is stopped and the abrasive grain layer is subjected to a treatment such as dressing to obtain an electrodeposited grindstone.

In an electrodeposited grindstone having such a structure, lubricating particles 7 are fixed around each superabrasive grain 6 to form a grinding wheel #i.
After forming the composite abrasive grains 3, the composite abrasive grains 3 are dispersed in the metal plating phase 2, so that the lubricating particles 7 are not unevenly distributed in the abrasive grain layer 4, and the abrasive grain layer is always maintained at an appropriate density. It is possible to expose the lubricating particles 7 from the surface of 4. Therefore, with such an electrodeposited grindstone, the coefficient of friction with the material to be ground can be reduced without causing the lubricant particles 7 to protrude beyond the surface of the abrasive grain layer 4 more than necessary, thereby reducing the sharpness of the grindstone. It is possible to reduce the grinding resistance, reduce the frictional heat generated during grinding, and prevent abnormalities such as overheating.

In addition, in this electrodeposited grindstone, a metal coating 8 is provided around the superabrasive grains 6.
Since the lubricating particles 7 have a relatively low bonding strength with the superabrasive particles 6, if a large force is applied to the superabrasive particles 6, the metal coating 8 will peel off from the interface between the lubricating particles 7 and the metal coating 8. The superabrasive grains 6 fall off. Therefore, with this electrodeposited grindstone, compared to conventional electrodeposition grindstones, it is possible to moderately reduce the superabrasive grain retention force, promote the self-generating full-edge action of the superabrasive grains 6, and improve the sharpness of the grindstone. At the same time, it is possible to reduce machining damage caused to the material to be ground. At the same time, since chip pockets can be easily formed, chip discharge performance can be improved, and the effect of retaining cooling water on the surface of the abrasive grain layer 4 can be increased, so that the cooling efficiency of the grindstone can be improved. moreover,
In this electrodeposited grindstone, there are pores 5 partially in the abrasive grain layer 4.
... is formed, and the abrasive grain layer 4 is made to have a porous structure, so that the above-mentioned effect becomes even more remarkable.

In addition, in the above embodiment, the abrasive grain layer 4 is made of composite abrasive grains 3.
However, the present invention is not limited to this, and composite abrasive ri3 and superabrasive grains that are not composite abrasive grains may be mixed and dispersed in the abrasive grain layer.

"Experimental Examples" Next, experimental examples of the present invention will be given to demonstrate the effects of the present invention.

(Experiment Example 1) ■Diamond super abrasive powder (200-240 mesh)
was soaked in a palladium salt aqueous solution to impart catalytic activity to the surface of the superabrasive grains.

■This super abrasive powder is mixed with an electroless cobalt plating solution (cobalt sulfate: 259/12, sodium succinate/259/
e1 Sodium sulfate: 15g/12, dimethylamine borane 29#SPH, 5.0, tL temperature (0°C) was dispersed to form a cobalt coating layer of approximately 3 μm on the surface of the superabrasive grain.

(2) The cobalt-coated superabrasive powder was sealed in a plastic bottle and magnetized by exposing it to a 5 kOe magnetic field.

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

■Super abrasive grain 1009 and hBN powder 20 treated as above
9 were sealed in a plastic bottle and thoroughly mixed, and a plurality of hBN particles were attached around the superabrasive grains by the magnetic force of the cobalt coating on the surface of the superabrasive grains.

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

■Next, this mixed powder was mixed with an electroless copper plating solution (OPC Copper S1 manufactured by Okuno Pharmaceutical Co., Ltd. Liquid temperature: 50°C)
Composite abrasive grains were obtained in which a 5μ thick copper coating was formed on the surface.

■Add 30vol 1% of the composite abrasive grains (average particle size) manufactured in this way to binder powder (phenolic resin), mix thoroughly, mold and fix on the grindstone base metal, then hot press. Then, it was fired and shaped into a grindstone shape to obtain a disc-shaped resinoid bond grinding wheel.

(Comparative Example 1) Diamond superabrasive grains (200 to 240 mesh) were added at 20vo1% to the same resin binder powder as in Experimental Example 1,
After thoroughly mixing, molding and fixing on the grindstone base,
Hot press and sinter, shape into a grindstone,
A resinoid bonded grindstone having the same shape as the experimental example was obtained.

Next, grinding was performed using the two resin 1' bonded grindstones under the following grinding conditions (wet type).

Grinding conditions Material to be ground: 96% alumina Grinding wheel peripheral speed:
1500x/win.

Feed rate: 　1　Ox/　min.

Cross feed: 2xm Depth of cut: 0.01zz Table 1 shows the grinding results of the two resinoid bond grindstones.

Table 1 As is clear from the above table, the grinding resistance was reduced in the renonoid bonded grindstone of the experimental example.

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

FIG. 3 is a longitudinal sectional view of the manufacturing equipment used at that time. Reference numeral IO designates a plating tank, and the plating tank 10 is filled with a plating solution M containing Ni ions. Further, a stirrer such as an ultrasonic stirrer (not shown) is provided in the plating tank IO. A non-conductive pedestal 11 is horizontally arranged in the plating tank IO, and a stainless steel flat substrate 12 is placed on the pedestal 11.

The upper surface of this flat substrate 12 is masked, leaving a portion forming the prototype shape of the grindstone to be manufactured. Further, above the flat substrate 12, an anode plate 13 is arranged parallel to the flat substrate I2, and is connected to an anode of a power source (not shown).

When manufacturing an electroformed thin blade grindstone, first, the plating tank 10
25μ of the plating liquid M in
A predetermined amount of composite abrasive grains having 2 μl of hBN particles arranged on the surface of the shoulder diamond superabrasive grains was added and uniformly dispersed in the plating liquid using a stirrer.

Next, the flat substrate 12 is connected to the cathode of the power source, and the anode plate 13 is connected to the cathode of the power source.
, and the Ni plating phase 1 is applied to the surface of the flat substrate 12.
4, composite abrasive grains were uniformly dispersed and incorporated into this Ni plating phase I4.

Eventually, when the metal plating layer 14 reached a predetermined thickness, the electricity supply was stopped, and the flat substrate 12 was taken out from the plating tank IO and washed with water. Then, the metal plating layer 14 was peeled off from the flat substrate 12, and the substrate was lapped and polished to form a predetermined shape, thereby obtaining an electroformed thin blade grindstone.

(Comparative Example 2) An electroformed thin-blade grindstone of Comparative Example 2 was created in the same manner as in Experimental Example 2, using superabrasive grains instead of composite abrasive grains.

Next, using the grindstones of Experimental Example 2 and Comparative Example 2,
Grinding and cutting were performed under the following grinding conditions.

Grinding conditions Material to be ground: Ferrite Grinding wheel peripheral speed: l 500 z/min Feed speed 100 zttt/min.

Depth of cut: 2.0xx Table 2 shows the results of grinding using these electroformed thin-blade grindstones.

(Hereinafter, blank spaces) Table 2 As shown in Table 2, the electroformed thin-blade grindstone of Experimental Example 2 was able to reduce grinding resistance and chipping compared to 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.

■After forming composite abrasive grains by fixing lubricating particles around individual superabrasive grains, the composite abrasive grains are dispersed in the metal plating phase to form an abrasive grain layer, so that It is possible to always expose the lubricant particles from the surface of the abrasive layer at an appropriate density without causing the lubricant particles to be unevenly distributed. therefore,
According to such an electroplated grindstone, the coefficient of friction with the material to be ground is lowered and the grinding resistance is reduced without causing lubricant particles to protrude from the surface of the abrasive grain layer more than necessary and reducing the sharpness of the grindstone. At the same time, it is possible to reduce the frictional heat generated during grinding and prevent the grindstone from overheating.

■Lubricating particles with relatively low bonding strength with the metal coating are placed around the superabrasive grains, so when a large force is applied to the superabrasive particles, the interface between the lubricating particles and the metal coating The metal coating peels off and the superabrasive grains fall off. Therefore, with this electrodeposited grindstone, the superabrasive retention force can be moderately reduced compared to conventional electrodeposited grindstones, and by promoting the self-generating full-edge action of the superabrasives, it is possible to improve the sharpness of the grindstone. ,
It is possible to reduce machining damage caused to the material to be ground. At the same time, since the formation of chip pockets becomes easier, it is possible to improve the evacuation of chips, and the effect of retaining cooling water on the surface of the abrasive grain layer is increased, thereby improving the cooling efficiency of the grindstone.

[Brief explanation of the drawing]

Fig. 1 is a partially enlarged cross-sectional view of an electrodeposited grindstone according to an embodiment of the present invention, Fig. 2 is a cross-sectional view of composite abrasive grains of the same grindstone, and Fig. 3 is a cross-sectional view of a grindstone according to an experimental example of the present invention. FIG. 2 is a longitudinal cross-sectional view of the manufacturing device.

Claims (1)

[Claims] Composite abrasive grains, which are made by adhering lubricating particles having an average particle diameter of 1/100 to 2/3 of the average particle diameter of the superabrasive grains with a metal coating, are dispersed in a binder phase. A whetstone characterized by having an abrasive grain layer.