JP2511330B2 - How to dress and dress diamond whetstones - Google Patents

Description

Detailed Description of the Invention

[0001]

This invention relates to a method for truing and / or dressing diamond wheels with high efficiency.

[0002]

2. Description of the Related Art A conventional grindstone using alumina or silicon carbide abrasive grains can be easily and highly accurately trued and / or dressed on a grinder by a diamond dresser. When using a rotary dresser, truing and dressing of a CBN grindstone are also possible. Processing using these whetstones achieves stable whetstone performance and a long dresser life, enabling mass production by grinding and forming.

On the other hand, when a diamond grindstone having diamond abrasive grains bonded thereto is trued or dressed with a diamond dresser, the cutting edge is made of a material having the same hardness, so that the dresser is greatly worn and the two contact with each other. There is a problem in that a severe rubbing occurs in the portion, and the amount of cut that is substantially obtained is extremely small.

FIG. 3A shows the amount of processing with respect to the cutting rate when a diamond grindstone using a resin bond is dressed with a diamond rotary dresser. The wear amount of the dresser is the dressing amount of the grindstone. The same amount has occurred. Further, about 90% of the uncut portion due to elastic deformation occurs with respect to the entire cut amount, and the actually obtained dressing amount is extremely small.

For this reason, conventional truing and dressing operations for diamond grindstones include a method in which a non-diamond grindstone is contacted and only the bonding layer is scraped off without using a diamond dresser, or a method utilizing electric discharge machining or electrolytic action. It is taken. But in this way,
There are problems that the work takes a considerably long time, dressing on the grinder is difficult, and the surface shape and runout of the diamond grindstone cannot be formed accurately.

Thus, in the conventional diamond grindstone,
It is difficult to form a highly accurate grindstone surface by truing, and it is necessary to finely adjust the grain size of the diamond grindstone in order to obtain the surface quality of the workpiece such as surface roughness. That is, in order to obtain good surface quality, it is necessary to use diamond abrasive grains having a fine grain size.

However, such a reduction in the diameter of the abrasive grains inevitably leads to a reduction in processing efficiency and a reduction in the life of the grindstone, which makes it difficult to apply the diamond grindstone to mass production by grinding.

Further, the poor precision of the grindstone surface due to truing and dressing makes it difficult to use the diamond grindstone in the form grinding in which high shape accuracy and runout accuracy are required.
There is also a problem that it is difficult to perform efficient form grinding with a diamond grindstone.

The present invention has been made in view of the above-mentioned problems, and it is possible to perform truing and dressing of a diamond grindstone with high efficiency and high accuracy, and it is possible to apply the diamond grindstone to mass production processing and form grinding. The aim is to provide a way to.

[0010]

In order to solve the above-mentioned problems, the present invention is designed to bring two diamond grindstones having different breaking strength against the compressive force of the abrasive grain bonding layer into contact with each other in a state of relative rotation. It has a small breaking strength
Use one diamond grindstone for the other
The method of truing and dressing with an earmond grindstone was adopted.

In the diamond dresser, since the diamond abrasive grains are firmly bonded by metal bonding, electroplating, etc., considering the processing state of the grindstone, the abrasive particles fall off from the bonding layer like the normal grinding process of the grindstone. There is almost no phenomenon of processing while doing so, and by applying compressive force from the dresser to the grindstone, the bonding layer of the grindstone is destroyed by the compressive force, or the bonding layer and the abrasive grains are separated it is conceivable that.

That is, the reason why the conventional diamond grindstone using a resin bond or a metal bond could hardly be trued by the diamond dresser is that the abrasive grain bonding layer by the resin bond or the metal bond is
It is considered that the structure is such that when a compressive force is applied, it is elastically deformed and is not broken or separated, and it cannot be processed by the compressive force from the dresser.

On the other hand, the fracture strength of the bonding layer against the compressive force is made different between the two diamond grindstones,
By contacting both of the whetstones and applying a compressive force, it is possible to break the bonding layer of one of the whetstones and separate it from the abrasive grains due to the difference in breaking strength. In this case, by replacing the diamond whetstone having a high breaking strength with a diamond dresser and the whetstone having a low breaking strength with a diamond whetstone to be processed, the diamond whetstone can be trued with high efficiency by a mechanical contact method by the dresser.

In the above method, the breaking strength of the bonding layer against the compressive force is determined by the hardness between the bonding layers and the transverse rupture force. That is, the bonding layer of a diamond grindstone having a low fracture strength (hereinafter simply referred to as a diamond grindstone) has a higher hardness and a higher bending strength than a bonding layer of a diamond grindstone having a high fracture strength acting as a blade (hereinafter referred to as a diamond dresser). When the force is set low, the strength at which the bonding layer of the diamond grindstone is plastically broken with respect to the compressive force can be made significantly smaller than that of the bonding layer of the dresser, and high working efficiency can be obtained.

In addition to the above characteristics, if the bonding layers of the diamond grindstone and the diamond dresser are both made of a material having a high Young's modulus, elastic deformation of both bonding layers when a compressive force is applied is reduced. be able to. Therefore, the uncut portion due to elastic deformation as shown in FIG. 3A can be greatly reduced, and highly efficient and highly accurate machining can be performed.

In order to obtain the above characteristics of the bonding layer most effectively, the bonding layer of the diamond grindstone is made of glass and the bonding layer of the diamond dresser is mainly composed of metal bond or electroplating. It is preferable to use a metallic material such as. That is, both the vitreous and metallic bonding layers have a high Young's modulus, and the difference in breaking strength as described above can be easily imparted between them. On the other hand, conventional resin bond layers such as resin bond have a large Young's modulus and thus have large elastic deformation, and in addition, it is difficult to adjust the breaking strength against compressive force. A treatment such as a treatment that can greatly change the breaking strength and Young's modulus is required.

Further, in the conventional bonding layer formed by a resin bond or a metal bond, as shown in FIG. 1B, all the spaces between the abrasive grains 1 are filled with the bond 2, and the surface is trued as shown by the line y. Even in this case, the abrasive grain 1 and the bond 2 are flush with each other, and the diamond abrasive grain 1 cannot act as a cutting edge. Therefore, it was necessary to perform dressing again after the truing so that the abrasive grains 1 were projected from the bond 2. On the other hand, as shown in FIG. 1a, when a large number of pores 3 are uniformly contained in the bonding layer, the diamond abrasive grains 1 are bonded to the bond 2 only by truing the surface of the grindstone like the line x. A rake face is projected from the rake face, and a cutting edge can be formed. That is, the structure allows dressing.

In order to uniformly form the pores in the bonding layer as described above, it is preferable that the main component of the bond is glass. That is, when diamond abrasive grains are mixed with a bond containing glass powder or the like as a main component, and the bond is melted to bond the abrasive grains, the vitreous bond 2 is bonded to the abrasive grains 1 by the surface tension as shown in FIG. 1a. A large number of pores 3 are formed inside by vitrifying in contact with each other and on the surface of the abrasive grains.

As a specific example thereof, the bond is a mixture of glass powder or silicate mineral powder, SiC or Al ₂ O ₃ powder as a filler, and a pore-forming material made of a wax or a thermal sublimation material. After the diamond abrasive grains are mixed in the bond, the bond layer is formed by firing to a temperature at which the bond is melted and vitrified or higher. In this case, the filler is 7 to 85% by weight and the pore-forming material is 0 to the weight of the entire bond.
It is preferable to blend in the range of -40% by weight. This allows
The bonding layer can contain pores in a volume ratio of 5 to 45%, and high dressing processability can be obtained.

On the other hand, the processing conditions for carrying out truing and dressing using a diamond grindstone and a diamond dresser having a bonding layer having the above structure must be limited in consideration of the wear of the dresser and the effect of processing heat. There is a need to do this under certain conditions. The following is
The recommended conditions for processing a grindstone using a diamond rotary dresser are shown below.

The dressing direction is such that the diamond grindstone and the rotary dresser are in the same direction at the contact point.

The peripheral velocities of the grindstone and the dresser are in the range of 0 <a <10 when the peripheral velocities of the grindstone and the peripheral velocities of the dresser are taken as the numerator and the peripheral velocities (a) of the both are taken. Set.

When the rotary dresser is traversed (moved laterally with respect to the surface of the grindstone) for truing and dressing as shown in FIG. 2a, the cutting depth per pass of the dresser is 1 to 10 .mu.m, and per revolution of the grindstone. The traverse amount (F) of the dresser is F = (0.01 to 0. 0 , where the contact width of the dresser to the grindstone is (b) .
2 ) xb mm / rev.

When truing and dressing the rotary dresser by plunge cutting as shown in FIG. 2b, the cutting speed is 0.005 to 0.5 μ per rotation of the grindstone.
Set in the range of m / rev.

[0025]

【Example】

<Experiment 1> Four types of diamond whetstone test products (A,
B, C, and D) were manufactured, and the dressing property by the diamond rotary dresser was compared with the conventionally used resin-bonded diamond grindstone.

The test products (A, B, C, D) were prepared by blending glass powder and silicic acid mineral powder as a binder raw material with a thermal sublimation material as a pore-forming material in an amount of 0 to 40% by weight of the binder raw material.
The formulation contains SiC as filler (particle size # 500)
Powder was mixed in a weight ratio as shown in Table 1 with respect to the weight of the binder raw material, and the mixture was mixed with diamond abrasive grains, and baked at a temperature not lower than the melting temperature of the binder raw material.

[0027]

[Table 1]

Each of the prepared test products (A to D) had a diamond grain size of # 400 and a diamond concentration of 100, and the mechanical properties of each test product are as shown in Table 1.
On the other hand, the resin-bonded diamond grindstone used for comparison had a diamond grain size of # 325 and a diamond concentration of 100.

On the other hand, the diamond rotary dresser uses a metal bond type and has a diamond grain size of #
40 and a diamond concentration of 100 were used. The mechanical properties of the tie layer of this dresser are as shown in Table 1.

The comparison results are shown in FIG. As shown in this figure, while the conventional resin-bonded diamond grindstone cannot perform truing / dressing at all with the diamond rotary dresser, each test product (A, B, C, D)
Showed an extremely large dressing rate, although there was a slight difference depending on the composition.

<Experiment 2> FIG. 4 shows a processing result when a cemented carbide is surface-ground by the above-mentioned test product A which is trued by a diamond rotary dresser and a resin bond diamond grindstone which is trued and dressed by a conventional method. . In FIG. 4, Fn is a normal direction grinding resistance, and Ft is a tangential direction grinding resistance.

As shown in the figure, the test product A has a slightly larger grinding resistance than the resin-bonded diamond grindstone, but has a large grinding ratio and shows excellent grinding performance.
It can be seen that dressing is performed well.

<Experiment 3> FIGS. 5 and 6 show the results of dressing the diamond grindstone of the test sample B using two types of diamond rotary dressers of the metal bond type and the electroplating type. Here, FIG. 5 shows the dressing ratio with respect to the cutting ratio, and FIG. 6 shows a diamond grindstone immediately after dressing with ceramics (Si ₃ N ₄ ).
Shows the grinding resistance in the case of grinding.

As shown in the figure, both types of dressers showed great truing / dressing properties. From this point of view, the specification of the dresser is preferably such that the bonding layer of the abrasive grains is made of metal by metal bonding or electroplating, and the diamond grain size is in the range of # 18-80 and the diamond concentration is in the range of 75-220. It is desirable to have.

<Experiment 4> FIGS. 7 to 14 show an appropriate truing test using the diamond grindstone of the test product B and the metal bond type diamond rotary dresser.
The test result which examined the processing conditions of dressing is shown.

FIGS. 7 and 8 examine the influence of the dressing direction. As shown in the figure, good results were obtained when the dresser direction was the same at the contact position between the grindstone and the dresser.

FIGS. 9 and 10 examine the effect of the peripheral speed ratio between the diamond grindstone and the diamond rotary dresser. Good results were obtained when the peripheral speed ratio a (dresser peripheral speed / grinding wheel peripheral speed) was in the range of 0 <a <10.

11 and 12 show the results of examining the influence of the cutting depth of the dresser. Good results were obtained in the range of the cut depth of 1 to 10 μm.

13 and 14 are for examining the influence of the dresser feed speed. From the results in the figure, when traversing the dresser, the traverse amount F =
In the case of (0.01 to 0.2 ) × b mm / rev, on the other hand, when plunging the dresser, the feeding speed is in the range of 0.005 to 0.5 μm / rev per one rotation of the grindstone. Good results are obtained.

[0040]

As described above, according to the method of the present invention, since truing and dressing can be performed only by bringing two diamond grindstones into contact with each other in a rotated state, it is easy and highly efficient on a grinding machine. It is possible to perform the polishing work of a diamond grindstone.

Therefore, if the present invention is utilized, the diamond grindstone can be applied to mass production processing by grinding, and there is an effect that the specification field of the diamond grindstone can be greatly expanded.

[Brief description of drawings]

1A is a diagram schematically showing an internal structure of a bonding layer, and FIG. 1B is a diagram showing another structural example.

2A is a diagram showing a processing example of a grindstone and a dresser, and FIG. 2B is a diagram showing another processing example.

FIG. 3 is a comparison diagram of dressing rates of diamond grindstones with different bonding layers.

FIG. 4 is a comparison diagram of grinding performance according to the difference in bonding layers.

FIG. 5 is a comparison diagram of dressing rates according to different rotary dressers.

FIG. 6 is a comparison diagram of grinding resistance immediately after dressing due to difference in rotary dresser.

FIG. 7 is a comparison diagram of dressing rates depending on the dressing direction.

FIG. 8 is a comparison diagram of grinding resistance immediately after dressing due to a difference in dressing direction.

FIG. 9 is a comparison diagram of dressing rates according to the same speed ratio.

FIG. 10 is a comparison diagram of grinding resistance immediately after dressing due to a difference in speed ratio.

FIG. 11 is a comparison diagram of dressing rates depending on the depth of cut.

FIG. 12 is a comparison diagram of grinding resistance immediately after dressing depending on the depth of cut.

FIG. 13 is a comparison diagram of dressing rates according to the difference in feed rate.

FIG. 14 is a comparison diagram of grinding resistance immediately after dressing due to difference in feed rate.

[Explanation of symbols]

 1 Abrasive grain 2 Bond 3 Pore

Claims (4)

(57) [Claims] 1. A diamond- bonding layer having a small breaking strength , which is brought into contact with two diamond grindstones having different breaking strengths against the compressive force of the abrasive-bonding layer in a state of being relatively rotated.
One of the diamond whetstones
Truing dressing a diamond grinding wheel, characterized in that the truing-dressing Yamondo grindstone. 2. A set abrasive grains bonded easily crush high hardness relative to layer characteristics of the other diamond grindstone of abrasive grains bonded layer of said one diamond wheel, pressure of the abrasive grain bonding layer
Two diamonds with different breaking strength against contraction
2. The truing / dressing method for a diamond whetstone according to claim 1, wherein the whetstone is formed, and the abrasive grain bonding layers of both of the diamond whetstones are both made of a material having a high Young's modulus. Wherein the major component of abrasive grain bonded layer of said one diamond wheel and vitreous, of the other diamond grindstone
And the main component of the abrasive bond layer to the metal, said one diamond
And the abrasive grain of the other diamond wheel
The truing / dressing method for a diamond grindstone according to claim 2, wherein the bonding layer is set to have a high hardness and is easily crushed . 4. A abrasive bond layer of said one diamond wheel, truing dressing a diamond grinding wheel according to claim 2 or 3, characterized in that uniformly in the presence of a large number of pores.