JP2003231006A - Holder for cutting tool, cutter main body for cutting tool, and cutting tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a holder having high machining precision, a cutter main body, and a cutting tool to solve a problem of uneven machining precision in cutting off, although the holder is made thick and short and a material having high strength is adopted to increase mechanical strength and improve machining precision, in the cutting tool in which a cutting chip is attached to the holder. <P>SOLUTION: This invention relates to the holder 2 for cutting tool in which a degree of face coarseness of a chip bearing surface 4 for fixing the cutting chip 3 is set in such a way that arithmetic average coarseness (Ra)=0.8 μm or less, the cutter main body for cutting tool, and the cutting tool 1 constituted by attaching the cutting chip to the holder 2 for cutting tool or the cutter main body for cutting tool. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting tool holder (hereinafter simply referred to as a holder), a cutting tool cutter body (hereinafter simply referred to as a cutter body), and a cutting tool.

[0002]

2. Description of the Related Art A cutting tool 1 shown in FIG.
The cutting tip 3 is attached to the tip of the
Used by mounting on machine tools such as automatic lathes or cam type lathes. The cutting tool 1 is of a throw-away type, and the cutting tip 3 is clamped on the tip seat surface 4 of the holder 2 with a screw 5, and can be replaced if necessary.

In the conventional method of manufacturing the holder 2, however, the raw material is cut and hardened, and then colored by, for example, a caustic soda solution (so-called black dyeing), etc., and then rust-proofed. It is common.

[0004]

As the technology becomes more sophisticated and complicated, the cutting tool 1 is also required to have high machining accuracy. Therefore, in the past, the holder 2 was made thicker and shorter, and a high-strength material was used to increase the mechanical strength, thereby improving the processing accuracy.
As shown in the graph, there was a problem that the machining accuracy varied during parting. In the graph of FIG. 5, the horizontal axis represents the number of processed workpieces, and the vertical axis represents the processed length of the workpieces.
The machining of the work for acquiring the data is performed by rotating the work W at a high speed around the center line Z as shown in FIG. 6, while moving the cutting tool 1 straight in the direction of the arrow Y to machine the work length. The turning conditions were input so that the length L was 20.94 mm. Then, the processing length L of the work after processing was measured to obtain data. In some cases, the cut portion of the work W after processing is inflated, as exaggerated in FIG. 6 and drawn by a chain double-dashed line. From the graph of FIG. 5, it is possible to confirm the magnitude of variation in the machining accuracy of the conventional cutting tool 1.

As a result of the applicant's search for the cause of variations in the machining accuracy of conventional cutting tools, a phenomenon in which the cutting tip 3 swings on the tip seat surface 4 has occurred, and such variations in the machining accuracy occur. It was found to be due to the shake of No. 3. Further, it has been found that the cause of the runout of the cutting tip 3 on the tip seat surface 4 is the fine unevenness of the tip seat surface 4. Normally, the surface roughness of the chip seat surface 4 is the arithmetic mean roughness (Ra) = 1.60 according to the drawing standard.
μm (* “Arithmetic mean roughness” will be described later.), which was considered sufficient, but
Surprisingly, such a surface state of the tip seat surface 4 has become an invisible factor that hinders the improvement of the machining accuracy of the cutting tool. Incidentally, the holder 2 of the cutting tool 1 used when creating the graph of FIG. 5 also follows the instruction that the surface roughness of the tip seat surface 4 is the arithmetic mean roughness (Ra) = 1.60 μm in the drawing standard. For reference, based on the conventional drawing standard, the surface roughness of the chip seat surface 4 is calculated as the arithmetic mean roughness (Ra) =
When five holders 2 were manufactured with the setting of 1.60 μm and the surface roughness of the chip seat surface 4 was measured, the arithmetic mean roughness (R
a) = 1.31 μm, 1.60 μm, 1.56 μm, 1.5
The results were 1 μm and 1.43 μm.

The present invention has been made in view of the above, and an object thereof is to provide a holder, a cutter body, and a cutting tool with high processing accuracy.

[0007]

[Means for Solving the Problems] The surface roughness of a tip seat surface for fixing a cutting tip is calculated as arithmetic mean roughness (Ra) = 0.8 μm.
Provided is a holder for a cutting tool, a cutter body for a cutting tool, and a cutting tool in which a cutting tip is attached to such a holder for a cutting tool or a cutter body for a cutting tool set as follows.

The surface roughness used in this application is
It is based on the surface roughness specified in JIS B0601 (Surface Roughness: Definition and Display). According to JIS B0601 (Surface Roughness: Definition and Display), the arithmetic mean roughness (R
The method of obtaining a) is as follows. * * * * How to obtain Ra Ra is obtained by extracting a reference length from the roughness curve in the direction of its average line, taking the X axis in the direction of the average line of this extracted portion, and taking the Y axis in the direction of vertical magnification. The roughness curve is y =
When expressed by f (x), it means that the value obtained by the following formula is expressed in micrometers (μm).

[0009]

[Equation 1]

However, when the surface roughness of the tip seat surface is set to arithmetic mean roughness (Ra) = 0.8 μm or less, the swing of the cutting tip with respect to the tip seat surface is suppressed, and the machining accuracy is improved. Further, the effect is more remarkable when the surface roughness of the tip seat surface is arithmetic average roughness (Ra) = 0.4 μm or less.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 is an exploded perspective view of the cutting tool, and FIG. 2 is a cross-sectional view of a main part.

The cutting tool 1 is of a so-called screw clamp type and has a holder 2 as shown in FIG.
And a cutting tip 3 and a screw 5 for clamping. The holder 2 is made of alloy steel, for example, and has a tip recessed in a stepped manner to form a chip seat surface 4, and a female screw hole 6 for screwing the cutting chip 3 to the chip seat surface 4 is formed.
Is formed. The cutting tip 3 is made of cermet or cemented carbide, and has a through hole 7 through which the screw 5 passes in the center. The cutting tip 3 is a so-called throw-away tip, which is clamped to the tip seating surface 4 of the holder 2 with a screw 5 and can be replaced if necessary.

The holder 2 is manufactured by molding (cutting) a raw material, quenching it, and then coloring it with, for example, a caustic soda solution (so-called black dyeing) to perform rust-preventing treatment, and then, the chip seat surface. 4, at least the hatched portion in FIG. 1 is machine-finished with an end mill.
The surface roughness of the chip seat surface 4 is arithmetic average roughness (Ra) = 0.8.
Set to less than μm. Five holders 2 were manufactured with this setting, and the surface roughness of the chip seat surface 4 was measured.
μm, 0.51 μm, 0.48 μm, 0.54 μm, 0.5
It was 8 μm. Further, the setting of the surface roughness of the tip seat surface 4 is changed to arithmetic average roughness (Ra) = 0.4 μm or less (specifically, the feed speed of the end mill is reduced) and the holder 2 is changed.
5 pieces were manufactured and the surface roughness of the chip seat surface 4 was measured. As a result, 0.27 μm, 0.21 μm, 0.27 μm, 0.18 μm
μm and 0.16 μm.

In the conventional method of manufacturing the holder 2, the raw material is molded (cut), the chip seat surface 4 is mechanically finished with an end mill, and then quenched to be rust-proofed. In this conventional method, since the surface roughness of the chip seat surface 4 is deteriorated by quenching, in order to realize the surface roughness of the chip seat surface 4 satisfying the conditions of the present invention, the surface roughness is finished to be higher than that. There is a need. One possible method is to reduce the feed rate of the end mill, but doing so lowers productivity and increases costs. On the other hand, in the method for manufacturing the holder 2 (the same applies to the cutter body 20 shown in FIG. 3) of the present invention, the surface modification of the chip seat surface 4 is performed after quenching. Can be avoided. Not only that, when a raw material and a material whose hardness has been increased by quenching are machine-finished under the same conditions, it has been confirmed that the latter improves the surface roughness. The method of manufacturing the cutter body is most suitable for implementing the holder 2 or the cutter body 20 of the present invention.

As is apparent from the above description, the present invention includes the following technical ideas. “A method of manufacturing a cutting tip mounting member such as a cutting tool holder 2 or a cutting tool cutter body 20 for mounting a cutting tip 3, which includes at least the following steps (a) and (b): (A) Forming a raw material and quenching it before modifying the surface of the tip seat surface for mounting the cutting tip (b) After quenching, the arithmetic mean roughness of the tip seat surface (Ra) = Surface modification to a surface roughness of 0.8 μm or less. ”Further, the arithmetic mean roughness (Ra) of the above technical idea is 0.4.
It is more effective if the thickness is less than μm. Furthermore, the chip seating surface may be subjected to anticorrosion treatment between the steps (a) and (b).

[0016]

[Processing accuracy variation confirmation test] The holder 2 is manufactured with the surface roughness of the chip seat surface 4 set to arithmetic mean roughness (Ra) = 0.4 μm or less, and the same procedure as described in the section of the prior art is used. Then, the graph of FIG. 4 was created. The turning conditions were input so that the processing length L of the work W would be 5.42 mm. From this result, it was confirmed that the machining tool 1 of the present invention has a small variation in machining accuracy. Although the data is omitted, the surface roughness of the tip seat surface 4 is calculated as the arithmetic mean roughness (Ra) =
Even when the thickness is set to 0.8 μm or less, the variation in processing accuracy becomes smaller than in the conventional case.

Although the present invention has been described with reference to the embodiments, the present invention is of course not limited to the above embodiments. For example, according to the present invention, as shown in FIGS. 3A and 3B, a cutting tool 1 (milling cutter) in which a plurality of cutting tips 3 are mounted on a tip seat surface 4 of a cylindrical cutter body 20, Although not shown, it can also be applied to an end mill. A wedge member 8 is used to attach the cutting tip 3 to the cutter body 20, and the button screw 9
Cutting tip 3 by the wedge principle by tightening
Is pressed against the chip seat surface 4 and fixed.

[0018]

EFFECT OF THE INVENTION The surface roughness of the tip seat surface is calculated as the arithmetic mean roughness (R
When a) = 0.8 μm or less, the deflection of the cutting tip with respect to the tip seat surface is suppressed, and the machining accuracy of the cutting tool is improved in comparison with the conventional product. The effect is that the surface roughness of the chip seat surface is arithmetic mean roughness (Ra) = 0.4 μm.
It is more remarkable in the following cases.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a cutting tool.

FIG. 2 is a sectional view of a main part.

FIG. 3 shows a cutting tool showing another embodiment (a)
Is a front view and (b) is a bottom view with half omitted.

FIG. 4 is a graph showing variations in machining accuracy of cutting tools.

FIG. 5 is a graph showing variations in machining accuracy of conventional cutting tools.

FIG. 6 is an explanatory view showing a turning state of a work.

FIG. 7 is a perspective view showing a conventional cutting tool.

[Explanation of symbols]

1… Cutting tool 2… Cutting tool holder 20 ... Cutter body for cutting tools 3… Cutting tip 4… Chip seating surface 5 ... screw

Claims (10)

[Claims] 1. A holder for a cutting tool, characterized in that a surface roughness of a chip seat surface for fixing a cutting chip is set to an arithmetic mean roughness (Ra) = 0.8 μm or less. 2. The cutting tool holder according to claim 1, wherein the arithmetic mean roughness (Ra) of the surface roughness is set to 0.4 μm or less. 3. The cutting tool holder according to claim 1 or 2, wherein at least the tip seat surface is subjected to rust-proofing treatment. 4. The holder for a cutting tool according to claim 1, wherein the clamping means of the cutting tip is a screw. 5. A cutter main body for a cutting tool, characterized in that the surface roughness of a tip seat surface for fixing a cutting tip is set to arithmetic average roughness (Ra) = 0.8 μm or less. 6. The cutter body for a cutting tool according to claim 5, wherein the arithmetic average roughness (Ra) of the surface roughness is set to 0.4 μm or less. 7. The cutter body for a cutting tool according to claim 5, wherein at least the tip seat surface is subjected to rust prevention treatment. 8. The cutting tool cutter body according to claim 5, wherein the cutting tip clamping means is a screw. 9. A cutting tool comprising a cutting tool holder or a cutting tool cutter body according to any one of claims 1 to 8 and a cutting tip attached thereto. 10. The cutting tool according to claim 9, wherein the cutting tip is made of cermet or cemented carbide.