JPH0760530A - Mirror surface cutting method and device by multi-edge cutter - Google Patents

Abstract

PURPOSE:To provide a mirror surface cutting method and device by a multi-edge cutter with which high precision mirror surface work can be achieved at a high efficiency using a cutter having plural cutting edges, with which specific surface roughness produced by feed of the cutter can be avoided, with which cutting resistance is small, and with which deterioration of surface roughness is small. CONSTITUTION:A device comprises a cutter 4 having plural cutting edges 2, and a grinding wheel 6 to grind the cutting edges at least periodically for correcting their tips, and each cutting edge comprises a tip part of worse machining performance and a back up part of better machining performance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mirror surface cutting method and apparatus, and more particularly to a mirror surface cutting method and apparatus using a multi-blade cutter having a plurality of blades.

[0002]

2. Description of the Related Art In recent years, with the development of processing technology and the demand for high efficiency and high accuracy, the realization of mirror surface processing by cutting (hereinafter referred to as mirror surface cutting) drastically improves efficiency and accuracy. Has been done. In such conventional mirror-cutting, usually, one blade, for example, one single-crystal diamond cutting tool is used, and a special precision processing machine is used to reduce the processed surface roughness with a minute feed amount to perform mirror-cutting. Was there. Further, since the machining efficiency is low in such cutting with a single blade, mirror surface cutting with a cutter having a plurality of blades (hereinafter referred to as a multi-blade cutter) has been required.

However, the tip of such a conventional tool for mirror cutting has a V or R shape, and the machined surface cannot avoid the surface roughness inherent to the feed of the blade. That is, in the case of mirror cutting with a single blade, as shown in FIG. 6 (A), the cutting edge has a constant locus during cutting, and a high precision dedicated machining machine table capable of minute feed is required. Therefore, the single blade has a low processing efficiency, and a general-purpose machine cannot be used.

On the other hand, in mirror cutting using a multi-blade cutter,
Although the machining efficiency is high, there is a positional unevenness (blade run-out) of each cutting edge with respect to the machining surface, and as shown in Fig. 6 (B), the cutting edge varies, and the roughness of the machining surface is a single blade. There was a drawback that it deteriorated compared to the processing by. Therefore, it has been conventionally desired to realize mirror cutting using a multi-blade cutter, for example, a well-known milling cutter and a general-purpose machine.

In order to solve such a problem, the same inventors as the present invention have provided a cutter having a plurality of cutting blades and grinding the cutting blades at least periodically during use of the cutter. A mirror surface cutting device composed of a grindstone for aligning blade edges was invented and filed (Japanese Patent Laid-Open No. 5-16014). By this invention, that is, "on-machine blade edge grinding", as shown in FIG. 7, it is possible to achieve highly efficient and highly accurate mirror surface machining using a cutter having a plurality of blades with uniform blade edges, and It was possible to avoid the surface roughness peculiar to the feed.

[0006]

However, in such a mirror surface cutting means, there is a problem that a flat portion having no clearance angle is formed at the cutting edge, and the flat portion causes an increase in cutting resistance.
Further, there is a problem that the surface roughness of the cut surface is deteriorated by the contact and friction of the flat portion with the work material. That is, the flat portion formed by cutting edge grinding in Japanese Patent Laid-Open No. 5-16014 is similar to the state in which the flank surface of a normal cutting edge is worn away and is in contact with the work material, which adversely affects the work surface. I understood it.

The present invention was devised to solve such problems. That is, the object of the present invention, it is possible to achieve a highly efficient and highly accurate mirror surface processing using a cutter having a plurality of blades, it is possible to avoid the surface roughness inherent from the feed of the cutter, It is an object of the present invention to provide a mirror surface cutting method and device using a multi-blade cutter, which has a small cutting resistance and little deterioration in surface roughness.

[0008]

According to the present invention, a cutting edge grinding step of grinding each cutting blade of a cutter having a plurality of cutting blades to align the cutting edges, and a flank face on each cutting blade A mirror surface cutting method using a multi-blade cutter is provided, which comprises a relief forming step for forming a slab and a cutting step of a work material by the cutter, and each step is performed on the same machine. .

According to a preferred embodiment of the present invention, each of the cutting blades is composed of a cutting edge portion having poor workability and a backup portion having good workability, and the cutting edge grinding step and the relief forming step include the cutting edge portion. And the simultaneous grinding process by the same surface of the grinding wheel of the backup part. Further, each of the cutting blades consists of a workable poor blade tip portion and a workable backup portion, and the blade tip grinding step consists of simultaneous grinding by the same surface of the grinding stones of the blade tip portion and the backup portion, It is preferable that the relief forming step includes simultaneous electric discharge electrolytic machining of the cutting edge portion and the backup portion.

Further, according to the present invention, there is provided a cutter having a plurality of cutting blades, and a grindstone for grinding the cutting blades at least periodically during use of the cutter to align the cutting edges thereof. There is provided a mirror-cutting device using a multi-blade cutter, wherein the plurality of cutting blades are composed of a cutting edge portion having poor workability and a backup portion having good workability. According to a preferred embodiment of the present invention, the poorly machinable cutting edge portion comprises a thin layer of diamond or CBN. Also,
The thin layer of diamond or CBN has a thickness of 0.25.
It is preferably mm or less. Further, it is preferable that the cutter is a milling cutter.

[0011]

The inventors of the present invention can simultaneously process a cutting blade composed of a blade portion having poor workability and a backup portion having good workability, so that the backup portion has a difference in grindability between the blade portion and the backup portion. It has been newly found that a slight flank can be formed in. The present invention has been established by confirming this through a test based on such new findings.

That is, according to the method of the present invention, a cutting edge grinding step of aligning the cutting edges of the respective cutting blades of a cutter having a plurality of cutting blades, and a flank forming step of forming a flank on each cutting blade, Since it consists of the cutting process of the work material with the cutter, and each process is performed on the same machine, it is necessary to achieve highly efficient and highly accurate mirror finishing using a cutter with multiple blades with the same cutting edge. In addition, it is possible to avoid the inherent surface roughness caused by the feed of the cutter. In addition, since the flank is formed on each cutting blade by the flank forming step,
It is possible to prevent an increase in cutting resistance and a deterioration in surface roughness.

Further, according to the apparatus of the present invention, each cutting blade of the cutter having a plurality of cutting blades is ground at least periodically to align the cutting edges, and each cutting blade is
Since the blade portion has poor workability and the backup portion has good workability, a slight flank is formed in the backup portion due to the difference in the grindability between the blade portion and the backup portion during this grinding process. As a result, it is possible to achieve highly efficient and highly accurate mirror surface processing using a cutter having a plurality of blades with the same cutting edge, avoiding the surface roughness peculiar to the cutter feeding, and escaping. The surface can prevent an increase in cutting resistance and a deterioration in surface roughness.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram of a mirror surface cutting device using a multi-blade cutter of the present invention. In this figure, a mirror surface cutting device with a multi-blade cutter according to the present invention includes a plurality of cutting blades 2.
And a grindstone 6 for grinding the cutting blade 2 at least periodically during use of the cutter 4 to align the cutting edges. In this figure, the cutter 4 is a milling cutter, and is attached below a spindle head (not shown) so as to be rotatable about a vertical axis. The cutter 4 has a plurality of chips, that is, cutting blades 2, which are fixed to the outer periphery of the lower surface of the cutter 4 at equal intervals.

A machine table 8 is placed below the cutter 4, and the cutter 4 and the machine table 8 can move up and down, left and right, and front and back relative to each other. Thereby, the cut d can be provided in the work material 1. The spindle head (not shown) to which the cutter 4 is attached and the machine table 8 are conventional general-purpose machines. The load table 10 is fixed to the upper surface of the machine table 8, and the work material 1 is further fixed to the upper surface thereof. Thereby, the cutting resistance acting on the work material 1 can be measured. Further, a drive device 12 for rotating the grindstone 6 is fixed to the upper surface of the machine table 8, and the grindstone 6 is fixed to the upper surface thereof. The upper surface of the grindstone 6 is a horizontal plane, the grindstone 6 is rotated around a vertical axis, and the cutter 4 having a plurality of cutting blades 2 is cut into the grindstone 6 (cutting δ), and the plurality of cutters 4 are cut. It is possible to bring the blade 2 into contact with the upper surface of the grindstone 6 and grind the cutting blade 2 at least periodically to align the cutting edges.

FIG. 2 is a diagram schematically showing a cross section of the cutting blade 2 according to the present invention. In the left diagram of the drawing, the plurality of cutting blades 2 according to the present invention include a cutting edge portion A having poor workability and a backup portion B having good workability. The difference in workability is due to, for example, difference in hardness, difference in material, or the like. In particular,
The cutting edge portion A having poor workability is preferably made of a thin layer of diamond or CBN (cubic boron nitride). Furthermore, the thickness of this thin layer of diamond or CBN is 0.25 mm.
The following is preferable.

It has been found that by simultaneously processing the cutting blade 2 having such a structure, a slight flank can be formed in the backup portion B due to the difference in workability between the blade tip portion A and the backup portion B. For example, by simultaneously grinding the cutting edge portion A and the backup portion B with the same surface of the grindstone, it is possible to form a flank surface on the backup portion B as shown in the right diagram of FIG. 2 (Example 1). Further, by the simultaneous electric discharge electrolytic machining of the cutting edge portion A and the backup portion B, it is possible to form a flank on the backup portion B as shown in (Example 2) and (Example 3) due to the difference in conditions. This flank can prevent an increase in cutting resistance and a deterioration in surface roughness.

With the apparatus having the above-described structure, it is possible to achieve highly efficient and highly accurate mirror surface machining by using the cutter 4 having a plurality of blades 2 having the same blade edge, and the unique surface roughness generated from the feeding of the cutter 4 is achieved. It is possible to avoid the roughness, and it is possible to prevent the increase of the cutting resistance and the deterioration of the surface roughness due to the flanks.

Next, a mirror surface cutting method using the multi-blade cutter of the present invention will be described. A mirror surface cutting method using a multi-blade cutter according to the present invention is provided for each cutting blade 2 of a cutter 4 having a plurality of cutting blades 2.
Edge cutting step of grinding the blades to align the cutting edges, a flank forming step of forming a flank on each cutting blade 2, and a cutter 4.
And a step of cutting the work material 1 by the above, and each of the steps is carried out on the same machine. Each cutting blade 2 used in this method is preferably composed of a cutting edge portion A having poor workability and a backup portion B having good workability shown in FIG.

The cutting edge grinding step is a simultaneous grinding process by the same surface of the grindstones of the cutting edge portion A and the backup portion B as shown in the right diagram of FIG. 1, and as a relief forming step, a cutting edge portion A and a backup are not separately shown. It is preferable to perform the simultaneous electric discharge electrolytic machining of the part B. As shown in the right diagram (example 1) of FIG. 2 and FIG. 3, the flank is formed in the backup part B by simultaneously grinding the cutting edge part A and the backup part B with the same surface of the grindstone. Therefore, the relief forming step may not be separately provided, and may be performed simultaneously in the blade edge grinding step.

According to the above-described method of the present invention, it is possible to achieve highly efficient and highly accurate mirror surface machining by using a cutter 4 having a plurality of blades 2 having a uniform cutting edge, and a unique characteristic resulting from the feeding of the cutter 4. The surface roughness can be avoided. Further, since the flanks are formed on the respective cutting blades 2 by the relief forming step, it is possible to prevent an increase in cutting resistance and a deterioration in surface roughness.

Next, the test results of the method and apparatus of the present invention will be described. FIG. 4 is a diagram showing the relationship between the degree to which the cutting blade 2 is ground to align the cutting edges (cutting edge cutting depth δ μm) and the roughness of the cutting surface by this blade 2 (RZ μm), FIG. 5 is a diagram showing the relationship between the cutting amount δ μm of the cutting edge and the cutting resistance (tangential force Ft, normal force Fn). 4 and 5, black circles (●) indicate the case where the entire cutting blade 2 is a cemented carbide tip made of cemented carbide, and in other cases, the cutting blade 2 has a cutting edge portion A made of a thin diamond layer. This is a case of a thin-layer diamond tip composed of a backup portion B made of a cemented carbide layer. The thickness of the diamond layer of the thin diamond tip is 0.1 mm (○),
Three types of 0.15 mm (∇) and 0.25 mm (∘) were tested.

From FIG. 4, the cutting surface roughness RZ μm is rapidly improved as the cutting edge grinding depth δ μm increases, and the cutting surface roughness when the cutting edge grinding depth is zero is about 2.0 μm. On the other hand, it can be seen that the cutting amount of the cutting edge is 20 μm or more and the cutting surface roughness is about 0.5 to 0.7 μm. Especially, it can be seen that the surface roughness of the thin-layer diamond tip (○, ▽, ◇) is smaller than that of the carbide tip (●). Further, from FIG. 5, as compared with the carbide tip (●), the thin-layer diamond tip (○, ▽, ◇) has a cutting resistance (tangential force Ft,
It can be seen that the normal force Fn) is low.

As described above, according to the method and apparatus of the present invention, it is possible to achieve highly efficient and highly accurate mirror finishing by using a cutter having a plurality of blades with a uniform cutting edge, and The inherent surface roughness resulting from the feed can be avoided. Further, since the flank is formed on each cutting blade, it is possible to prevent an increase in cutting resistance and a deterioration in surface roughness.

[0025]

Therefore, the method and apparatus of the present invention can achieve highly efficient and highly accurate mirror finishing by using a cutter having a plurality of blades, and the inherent surface roughness caused by the feed of the cutter can be achieved. It can be avoided, and the cutting resistance is small,
It has excellent effects such as less deterioration of surface roughness.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a mirror surface cutting device using a multi-blade cutter according to the present invention.

FIG. 2 is a diagram schematically showing a cross section of a cutting blade according to the present invention.

FIG. 3 is a diagram schematically showing the action of the present invention.

FIG. 4 is a view showing a relationship between a cutting amount of a cutting edge and roughness of a cutting surface.

FIG. 5 is a diagram showing a relationship between a cutting amount of cutting edge and cutting resistance.

FIG. 6 is a diagram schematically showing a cutting surface by a conventional device.

FIG. 7 is a diagram schematically showing smoothing of a machined surface by a conventional on-machine cutting edge grinding method.

[Explanation of symbols]

 1 Work Material 2 Cutting Blade 4 Cutter 6 Grinding Stone 8 Machine Table 10 Load Cell 12 Drive Device A Blade Edge B Backup Section

Claims (7)

[Claims] 1. A cutting edge grinding step of grinding each cutting blade of a cutter having a plurality of cutting blades to align the cutting edges,
A multi-blade cutter, comprising a flank forming step of forming a flank on each of the cutting blades, and a step of cutting a workpiece with the cutter, wherein each step is carried out on the same machine. Mirror surface cutting method. 2. Each of the cutting blades comprises a cutting edge portion having poor workability and a backup portion having good workability, and the cutting edge grinding step and the relief forming step are performed on the same surface of the grindstone of the cutting edge portion and the backup portion. The method of mirror cutting with a multi-blade cutter according to claim 1, wherein the method comprises simultaneous grinding. 3. Each of the cutting blades is composed of a blade portion having poor workability and a backup portion having good workability, and the blade edge grinding step is a simultaneous grinding process using the same surface of a grindstone of the blade portion and the backup portion. 2. The mirror cutting method with a multi-blade cutter according to claim 1, wherein the relief forming step comprises simultaneous electric discharge electrolytic machining of the blade tip portion and the backup portion. 4. A cutter having a plurality of cutting blades, and a grindstone that grinds the cutting blades at least periodically during use of the cutters to align the cutting edges of the cutters. A mirror surface cutting device with a multi-blade cutter, characterized by comprising a cutting edge portion having poor workability and a backup portion having good workability. 5. The mirror cutting device with a multi-blade cutter according to claim 4, wherein the cutting edge portion having poor workability is made of a thin layer of diamond or CBN. 6. The mirror cutting device with a multi-blade cutter according to claim 5, wherein the thickness of the thin layer of diamond or CBN is 0.25 mm or less. 7. The cutter is a milling cutter,
The mirror surface cutting device with a multi-blade cutter according to claim 4, wherein