JP2000176833A - Diamond grindstone for ultrasonic machine truer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform truing in high efficiency and in high precision by restraining abrasion and deformation of a truing grinding wheel at the time of truing a machining tool while adding an ultrasonic wave to the machining tool of an ultrasonic machine. SOLUTION: An abrasive material layer of a diamond grinding wheel is made into an abrasive material layer made of 40-50 volume% of frit consisting of a mixture of SiO2: 25-35 weight%, Al2O3: 20-30 weight%, ZnO: 20-30 weight%, B2O3: 5-35 weight%, 0.5-18 volume% of SiC, 0.5-5 volume% of BN, 57-75 volume% of vitrified bond containing 0.5-2 volume% of Sn and 25-43 volume% of diamond abrasive grains.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diamond grindstone for truing a processing grindstone in a state where ultrasonic waves are applied to a processing grindstone of an ultrasonic processing machine.

[0002]

2. Description of the Related Art In recent years, as a high-efficiency and high-precision machining method for hard-to-cut materials and high-hardness brittle materials, ultrasonic machining for applying machining to a machining tool while applying ultrasonic waves has been adopted. Ultrasonic machining is a process in which a tool that ultrasonically vibrates in the axial direction at a frequency of about 20 to 60 kHz and an amplitude of about 1 to 20 μm is pressed against a workpiece with a constant pressure, and machining is performed while supplying a grinding fluid to the gap. is there.

[0003] A diamond wheel is most frequently used as a machining tool for this ultrasonic machining. As is well known, diamond wheels are classified into resin bond wheels, metal bond wheels, and vitrified bond wheels according to the type of bonding agent (bond). In the case of ultrasonic processing, diamond wheels are generally used to withstand ultrasonic vibration loads. Metal bond wheels are applied.

[0004]

By the way, in order to achieve high-precision and high-quality machining, truing (run-out and reshaping) of a diamond wheel is important. In particular, immediately after the diamond wheel is mounted on the main shaft of the machine, the run-out due to the mounting often occurs, and proper processing does not proceed. Therefore, truing of the diamond wheel is performed using a truing grindstone.

Regarding the truing of the diamond wheel, the present inventors have been studying truing while applying ultrasonic waves while attaching the diamond wheel to an ultrasonic machine. Metal bond has the best wear resistance among various types of bonds, so truing is difficult.However, it was confirmed that efficient truing is possible by performing truing while applying ultrasonic waves to the diamond wheel. did.

On the other hand, when truing is performed while applying ultrasonic waves to a diamond wheel using a vitrified bond grindstone which has been generally used as a truing grindstone, the truing grindstone is significantly worn and deformed. It turned out that there was a problem in achieving high-precision truing.

A vitrified bond grinding wheel conventionally used as a truing grindstone is SiC, Al ₂ O.
A grindstone that uses ₃ abrasive grains and has about 40% to 50% pores. However, in such a truing grindstone, the abrasive grains and the bond are greatly destroyed by the ultrasonic vibration load, and the wear increases. It is considered that the collapse becomes large.

The problem to be solved by the present invention is that when truing a machining tool while applying ultrasonic waves to the machining tool of the ultrasonic machining machine, the truing grindstone is prevented from being worn out and the shape thereof being deformed, and the efficiency and the efficiency are improved. It is an object of the present invention to achieve truing with high accuracy.

[0009]

SUMMARY OF THE INVENTION A diamond grindstone for an ultrasonic processing machine truer according to the present invention is a grindstone for performing truing of a processing tool while applying ultrasonic waves to the processing tool of the ultrasonic processing machine. ₂ : 25 to 35% by weight, Al
₂ O _3: 20 to 30 wt%, ZnO: 20 to 30 wt%, B ₂ O _3: 5~35 wt% mixture frit 40-50% by volume consisting of the SiC 0.5 to 18% by volume,
It is a diamond grindstone provided with an abrasive layer comprising 57 to 75% by volume of a vitrified bond containing 0.5 to 5% by volume of BN and 0.5 to 2% by volume of Sn and 25 to 43% by volume of diamond abrasive grains. .

The diamond grindstone for an ultrasonic processing machine truer of the present invention (hereinafter referred to as a truing grindstone) is characterized in that the bond is a vitrified bond having the above component range and the diamond grindstone is used as the abrasive grain. There is no increase in wear due to the large destruction of the abrasive grains, and there is no increase in shape collapse due to this.

Here, SiO ₂ in the bond acts to lower the expansion coefficient and increase the holding power of the abrasive material. If the content is less than 25% by weight, the flow of the bond becomes large and the formability is impaired. However, if it exceeds 35% by weight, the bond cannot be melted and the moldability becomes insufficient. Al ₂ O ₃ acts to increase the strength of the bond. If the content is less than 20% by weight, the strength decreases, and if it exceeds 30% by weight, molding becomes insufficient. ZnO acts to increase the coefficient of expansion and has a content of less than 20% by weight and 30%.
If the content is more than% by weight, the control becomes difficult. B ₂
O ₃ has the effect of lowering the expansion coefficient and increasing the heat resistance. If the content is less than 5% by weight, the effect will not be obtained, and if it exceeds 35% by weight, the effect will be lost.

Further, 0.5 to 18% by volume of SiC improves the strength, 0.5 to 5% by volume of BN enables adjustment of the bonding degree, and 0.5 to 2% by volume of Sn improves the formability.
Exceeding this range may cause molding hindrance.

By using a vitrified bond having the above component range, the bond matrix is strengthened. By combining this bond with diamond abrasive grains, the holding power of the abrasive grains is improved, and the shape retention and processing efficiency are excellent. A truing whetstone is obtained.

Further, by selecting a specific range from the above component ranges so that the three-point bending strength of the vitrified bond is 100 to 150 MPa, bond destruction is reduced, and abrasion and shape collapse are reduced. Can be done. Since the switching is continued by the minute destruction, the effect of maintaining the sharpness is obtained. When the three-point bending strength is lower than 100 MPa, bond breakage becomes large, so that abrasion and shape collapse are promoted.
When the pressure exceeds 0 MPa, the breaking of the bond becomes extremely small,
This is not preferable because the switching does not continue and the persistence of sharpness is reduced.

The three-point bending strength of the vitrified bond is 1
In order to adjust the pressure to 00 to 150 MPa, in the above-mentioned component range, 10 to 18% of SiC and 2 to 5% of BN are added.
% And Sn may be limited to the range of 0.5 to 2%. In the case of a resin bond, the three-point bending strength is about 50 to 70 MPa, and in the case of a metal bond, it is about 450 to 500 MPa. It is not suitable for

Further, by selecting a specific range from the above-mentioned component ranges so that the porosity of the abrasive layer is 3% or less, the abrasive layer is not largely destroyed, and the abrasive grain holding power is reduced. A grinding stone with excellent shape retention and stable sharpness can be obtained. If the porosity is more than 3%, the abrasive layer will be broken, resulting in inferior abrasive holding power, shape retention and sharpness, which is not preferable. In order to reduce the porosity of the abrasive layer to 3% or less, the SiC should be further added within the above-mentioned component range.
What is necessary is just to limit 18%, BN to 2-5%, and Sn to 1.5-2%.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on experimental examples. FIG. 1 is a diagram showing the configuration of a truing device used in the experiment.

In FIG. 1, S is the rotating spindle of the ultrasonic machine, D is a machining tool (diamond wheel), T is a truing grindstone, arrow A is the rotating direction of the rotating spindle S,
Arrow B indicates the rotation direction of the truing grindstone T, and arrow C indicates the cutting direction of the truing grindstone T. The processing tool D and the truing whetstone T rotate in the same direction, but the rotational peripheral speed of the processing tool D is 11 m / min, and the truing whetstone T
Is 40 m / min, and truing is performed by the difference in the rotational peripheral speed.

The truing whetstones used in the experiment were diamond whetstones using vitrified bonds within the composition range of the present invention (Invention products 1 to 3), and diamond whetstones having vitrified bond compositions outside the composition range of the invention (comparative products). 1
To 3), the bond composition is within the composition range of the present invention, but a grindstone using SiC as abrasive grains (Comparative Product 4), a grindstone using diamond but using a metal bond as a bond (Comparative Product 5) Similarly, nine abrasives (comparative product 6) using diamond as a bond but using a resin bond as a bond. Table 1 shows the bond composition and grinding wheel characteristics of the truing whetstone used in the experiment.

[0020]

[Table 1]

As shown in Table 1, the grindstones of the invention products 1 to 3 are excellent in all of the properties of the three-point bending strength of the bond, the porosity of the abrasive layer, the formability of the abrasive, and the abrasive holding power. The tool run-out after truing was good at 2 μm or less. The grindstones of the comparative products 1 to 3 in which the composition of the vitrified bond was out of the composition range of the present invention had a good tool runout after truing of 2 μm or less, but the moldability of the abrasive material was slightly poor, and In some cases, the three-point bending strength and the porosity of the abrasive layer were out of the preferred ranges. The grindstone of the comparative product 4 using the vitrified bond and the SiC abrasive grains within the composition range of the present invention has the three-point bending strength of the bond and the porosity of the abrasive layer out of the preferable ranges, and the tool runout after truing. Was as large as 15 μm. The grindstone of the comparative product 6 using a metal bond as a bond and the grindstone of a comparative product 7 using a resin bond as a bond have a three-point bending strength of a bond and a porosity of an abrasive material layer greatly deviating from preferable ranges. The later tool runout exceeded 100 μm and was defective.

The truing conditions are as follows.・ Ultrasonic frequency: 40 kHz ・ Amplitude: 10 μm ・ Machining tool specifications: SD140-100M, 7D × 5T ・ Machining tool peripheral speed: 11 m / min ・ Trueing whetstone specifications: Invention products 1-3 SD100V, 75D × 10T Comparison products 1 3 SD100V, 75D × 10T Comparative Product 4 GC100V, 75D × 10T Comparative Product 5 SD100M, 75D × 10T Comparative Product 6 SD100B, 75D × 10T ・ Trueing wheel peripheral speed: 40 m / min ・ Cutting amount: 20 μm / pass ・ Grinding fluid: Soluble × 50

FIG. 2 shows the results of truing. In FIG. 2, the horizontal axis indicates the number of cuts, and the vertical axis indicates the runout amount of the processing tool after truing. As can be seen from the figure, when truing with the grindstone of the comparative product 5 using a metal bond as the bond or the comparative product 6 using a resin bond as the bond, the convergence value of the run-out amount of the processing tool is 100 μm.
m or 120 μm, and truing was insufficient. When truing was performed with the grindstone of the comparative product 4 using the vitrified bond and SiC abrasive grains within the composition range of the present invention, the convergence value of the run-out amount was 1 at 9 cuts.
Although the shape was reduced to 5 μm, the shape of the processing tool after truing was such that the tip portion was tapered, and the accuracy could not be maintained. On the other hand, when the truing is performed with the grindstones of the invention products 1 to 3, the convergence value of the run-out amount is reduced to 2 μm at the number of cuts of 7 (FIG. 2 shows an average value of three pieces), and the processing tool after truing is performed. Was also maintained in a good state. When the composition of the vitrified bond was trued with the grindstones of the comparative products 1 to 3 out of the composition range of the present invention, the tool runout was almost the same as that of the grindstones of the invention products 1 to 3, but the abrasive material layer Wear and shape collapse were large, and truing accuracy was insufficient.

[0024]

By using a vitrified bond having a specific component range and using diamond abrasive grains as abrasive grains, when truing is performed with ultrasonic waves applied to the working tool, the wear of the grinding stone is small, and the shape collapse occurs. A truing whetstone that is difficult to perform can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a truing device used in an experiment.

FIG. 2 is a graph showing a truing result.

[Explanation of symbols]

 S Rotating spindle of ultrasonic processing machine D Processing tool (diamond wheel) T Truing whetstone

Claims (1)

[Claims] 1. A grinding wheel for carrying out the truing machining tool while applying ultrasonic waves to the machining tool of the ultrasonic processing machine, SiO _2: 25 to 35 wt%, Al ₂ O _3: 20
30 wt%, ZnO: 20 to 30 wt%, B ₂ O _3:
A frit consisting of a mixture of 5 to 35% by weight is 40 to 50%.
Volume%, SiC 0.5-18 volume%, BN 0.5-
Vitrified bond containing 5% by volume and 0.5 to 2% by volume of Sn, 57 to 75% by volume, and diamond abrasive grains 25 to 4
A diamond grindstone for an ultrasonic processing machine truer provided with an abrasive layer of 3% by volume.