JP2003334715A - Taper end mill for machining rib groove - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a taper end mill for machining a rib groove for obtaining the excellent taper accuracy of a rib groove, for example, with straightness of 0.01 mm or less and an average taper angle of ±0.15 degrees or less relative to a reference taper angle. <P>SOLUTION: This taper end mill for machining a rib groove has two or more tapered outer blades. A first flank and a second flank are provided backward in a tool rotative direction from the edge line of the outer blade. A first clearance angel of the first flank is set to 0.5 degrees or more and 7 degrees or less, and a second clearance angle of the second flank is set to 10 degrees or more and 20 degrees or less. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a taper end mill for machining a rib groove which is used for machining a rib groove by using a machine tool such as a machining center.

[0002]

2. Description of the Related Art Rib groove machining is a machining method in which a small number of incisions in the axial direction of the tool of 0.02 mm to 0.1 mm are divided into several tens to several hundreds to reach a predetermined depth. Yes, unlike side cutting or pocket machining, the tool is machined in a state in which it is constrained on both sides, resulting in extremely poor chip discharge performance. As a tool for performing such rib groove processing, during cutting, since the end mill experiences sagging and chatter vibrations, the weaker the rigidity, the greater the vibration, which affects the surface to be cut of the machining work. If it is strong, the precision of the machined surface will deteriorate.

[Patent Document 1] Japanese Unexamined Patent Application Publication No. 2001-310211 (page 4, FIG. 1)

[Patent Document 2] JP-A-9-29531 (page 3,
(Fig. 2)

[Patent Document 3] Japanese Unexamined Patent Publication No. 2000-246532 (page 3, FIG. 3) In Patent Document 1, the core thickness with respect to the outer diameter of the tool is gradually increased from the end blade side toward the blade base side, and the rigidity of the end mill is increased. In Patent Documents 2 and 3, for flank cutting, the flank shape is devised in order to improve the processed surface roughness.

[0003]

What is important in rib groove machining is not only the surface to be cut, but also the precision with which the die is removed during molding, that is, the taper precision, which is the clearance of the rib groove. It will be the biggest factor. The present invention provides excellent rib groove taper accuracy, for example, straightness within 0.01 mm, and average taper angle ± 0.1 with respect to the reference taper angle.
An object is to provide a taper end mill for rib groove processing that can obtain within 5 degrees.

[0004]

According to the present invention, in a taper end mill for rib groove machining, the outer peripheral blade is formed of two or more blades and forms a taper shape, and from the ridgeline of the outer peripheral blade toward the rear in the tool rotation direction. The first flank and the second flank are provided, and the first flank angle of the first flank is 0.5 degrees or more and 7 degrees or less, and the second flank is
The taper end mill for machining a rib groove is characterized in that the second clearance angle of the flank is 10 degrees or more and 20 degrees or less.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION When a taper-shaped rib groove is machined, the tool is machined in a state in which it is restrained on both sides, and chip clogging occurs extremely as compared with normal side surface cutting and pocket machining. Since it is easy, biting of chips has a great influence on the taper finish surface accuracy of the rib groove. This is because the chips adhere to the flank surface, which causes biting between the tool and the work material during cutting, and this phenomenon was prevented. In the present invention, the first flank and the second flank are provided so that the first flank angle is set to be relatively gentle. Therefore, the second flank larger than the first flank angle at the rear end of the first flank face. By providing the surface, the clearance with the work material is increased, and it is possible to suppress the biting of chips. When the first clearance angle is 0.5 degrees or more and 7 degrees or less and special machining such as a rib groove is performed, if the cutting edge of the tool edge is too good, the flow of chips to the rake surface side and the flank surface side Chips flow out to. The chips that have flowed out to the flank face are welded, and the chips are bitten, which significantly deteriorates the taper accuracy. When the first clearance angle is reduced, a burnishing effect is given to the cutting surface, and chips during cutting are less likely to flow out to the clearance surface side. When the first clearance angle is smaller than 0.5 degree, the clearance between the first flank and the work material becomes too small, and the first flank is rubbed against the work material, so that the accuracy is rather deteriorated. Clearance angle is 7
If it exceeds the degree, it becomes impossible to sufficiently suppress the outflow of chips to the flank side during cutting, so the first clearance angle is set to 0.5 degrees or more and 7 degrees or less.

The reason why the second clearance angle is set to be 10 degrees or more and 20 degrees or less is that the first clearance angle is small. Therefore, in order to remove the chips that slightly flowed out to the clearance surface side, the second clearance angle is set behind the first clearance surface. In, it is necessary to increase the clearance with the work material. A second flank is provided rearward of the first flank in the tool rotation direction, and the second flank angle is set to 10 degrees or more and 20 degrees or less. If the second clearance angle is less than 10 degrees, the small chips that have flowed out to the flank surface cannot be removed sufficiently,
Biting occurs between the tool and the work material, and satisfactory taper accuracy cannot be obtained. When the second clearance angle exceeds 20 degrees,
The back metal of the cutting edge cannot be sufficiently secured, and the rigidity is reduced, which causes chattering vibration, which deteriorates the surface to be cut, and the taper accuracy cannot be obtained. Here, it is preferable to attach an eccentric blade to the second flank in order to impart rigidity to the cutting edge.

As an embodiment, the first flank may have a center line average surface roughness Ra of 0.3 μm or less. Here, the maximum height Ry is generally used as a criterion for determining whether the surface roughness is good or bad. However, it is important that the surface roughness is a stable surface. Ra, which is widely used as a criterion of stability, is evaluated. If the surface roughness Ra of the first flank exceeds 0.3 μm, some of the chips that have flowed out to the flank face will stay in the irregularities of the surface and cause welding, adversely affecting the taper accuracy. Therefore, Ra is preferably 0.2 μm or less.

The coating is made of Al, Si, B, on the first flank.
Carbides, carbonitrides of metals of groups 4a, 5a and 6a of the periodic table,
Nitride, oxide, boride and boron carbide, hard boron nitride,
One or more hard coatings selected from the group consisting of hard carbon, and solid solutions or mixtures thereof;
You may coat the film of 2-10 micrometers in thickness. By providing the film, the welding of chips to the flank can be further improved. Further, when a film is provided, since unevenness is caused by droplets or the like formed by vapor deposition after film formation, it is desirable to remove these droplets or the like by polishing. As a polishing method for removing, there are a magnetic polishing method, a shot blasting process, a honing process with a brush, a buffing process and the like.

The end shape of the end mill is a taper radius end mill having a corner R blade at the end corner and a taper ball end mill having a ball blade as the end blade to suppress local wear and chipping and to form deep rib grooves. Even in this case, stable cutting can be performed and good taper accuracy can be obtained. In the taper radius end mill, the radius of the corner R is preferably 5% to 40% of the tip diameter. Less than,
The present invention will be specifically described based on examples.

(Embodiment 1) The first embodiment of the present invention is shown in FIGS.
Tool tip material made of cemented carbide as shown in Fig. 1 has a tool tip blade diameter of 1 m
m, the taper angle 1 degree, the first flank 3 and the second flank 4 from the cutting edge ridge of the outer peripheral blade 2 toward the rear in the tool rotation direction.
The first clearance angle 5 is 5 degrees, the second clearance angle 6 is 15 degrees, the first clearance surface width 7 is 0.04 mm, and the TiAlN coating is 3 μm. For comparison, Example 1 of the present invention
3 and 4, the flanks shown in FIG. 3 and FIG. 4 are only the first flanks 3 and the second flanks are not provided, and the first flank angle 5 is 15 degrees. − 3 μm
Coated. A cutting test was performed to compare the taper accuracy and the surface roughness of the cut surface. The taper accuracy was measured by measuring the taper shape of the left side surface of the rib groove in FIG. 5 and using a contact type contour shape measuring instrument and a stylus having a radius of tip radius of 0.025 mm. As for the cutting specifications, a pre-hardon steel having a hardness of HRC38 was used as a work material, the rotation speed was 20000 min ⁻¹ , and the feed rate was 500 m
m / min, depth of cut 0.02 mm / in the axial direction of the tool
The test was carried out by a wet method using a water-soluble cutting fluid. The shape of the reciprocating rib groove cutting is, as shown in Fig. 5, the width of the bottom is 1 m.
The depth was 12 mm, the taper angle 8 of the rib groove was a blind groove of 1 degree, and machining was performed with 600 tool axis step steps. As a result, Example 1 of the present invention can perform stable machining even during machining, and as shown in FIG. 6, the measurement line 1 is substantially overlapped with the reference line 9 having a taper angle of 1 degree, which is the reference taper angle.
0 was obtained, and the taper accuracy was straightness 0.004 mm,
The average taper angle 11 is 0.95 degrees, that is, the difference in angle is −0.
The surface roughness to be cut was Ry as small as 0.8 μm. In Conventional Example 2, chatter vibration occurs during cutting, the measurement line 10 is separated from the reference line 9 and has a stepped shape, as shown in FIG. Angle 11 is 0.6 degrees, that is, -0.4 in terms of angle difference
The surface roughness to be cut in the tool axis direction was Ry of 2.5 μm.

(Embodiment 2) The first embodiment has the same specifications as the first embodiment of the present invention.
The clearance angle is 0 degree for Comparative Example 3, 0.3 degree for Comparative Example 4, 0.5 degree for Invention Example 5, 1 degree for Invention Example 6, 3 degrees for Invention Example 7, and Invention Example. 8 as 7
, 9 degrees for Comparative Example 9 and 11 degrees for Comparative Example 10, nine types of taper end mills for rib groove processing were manufactured and a cutting test was conducted. The cutting specifications are S50 of carbon steel as the work material.
C, rotation speed 20000 min ^{- 1} , feed rate 50
0mm / min, depth of cut is 0.02m in tool axial direction
Reciprocating rib groove cutting was carried out by a wet method using a water-soluble cutting fluid at m / times, and the same evaluation as in Example 1 was performed. as a result,
Inventive Examples 1 and 5 to 8 are stable processing, and the taper accuracy is a highly accurate finish in the range of straightness of 0.008 mm or less and angle difference of -0.02 degrees to -0.1 degrees. The accuracy was shown and the surface to be cut was also good. Comparative Examples 3 and 4
Since there is no clearance between the first flank and the work material, or there is very little clearance, the cutting surface is rubbed, and the taper accuracy is good because the straightness is 0.01 mm or less due to the effect. The angle difference was inferior at -0.25 degrees to -0.3 degrees. In Comparative Examples 9 and 10, welding was observed on the first flank after processing, and the taper accuracy was straightness 0.024 to 0.026.
mm, the angle difference was inferior to -0.2 degrees to -0.3 degrees.

(Embodiment 3) The second embodiment has the same specifications as the first embodiment of the present invention.
The clearance angle is 8 degrees as Comparative Example 11 and the invention example 1
2 as 10 degrees, invention example 13 as 12 degrees, invention example 14 as 14 degrees, invention example 15 as 16 degrees, invention example 16 as 18 degrees, invention example 17 as 20 degrees, and comparative example 18 as 22 degrees. 8 types of end mills were manufactured, and the same cutting test and evaluation as in Example 2 were performed. as a result,
The end mills of Inventive Examples 12 to 17 are stable in processing, have a good surface to be cut, and have a taper accuracy of 0.008 m in straightness.
High-precision finishing accuracy was shown in the range of m or less and the angle difference of −0.02 degrees to −0.1 degrees. In Comparative Example 11, after cutting, deposits were confirmed on the first flank and the second flank, and the taper accuracy was inferior with a straightness of 0.015 mm and an angle difference of −0.2 degrees. In Comparative Example 18, chattering / vibration was generated, minute chipping was observed, and the taper accuracy was a straightness of 0.018 mm and an angle difference of −0.3 degrees.

(Embodiment 4) The first embodiment has the same specifications as the first embodiment of the present invention.
By changing the grain size of the abrasive grains of the grinding wheel together with Invention Example 1 in which the flank surface has a surface roughness Ra of 0.2 μm, the surface roughness of the first flank surface is Ra and is 0.15 μm in Invention Example 19 respectively. Four types of end mills of 0.3 μm as Inventive Example 20 and 0.5 μm as Inventive Example 21 were manufactured, and the same cutting test and evaluation as in Example 2 were performed. As a result, in Inventive Example 1 and Inventive Examples 19 and 20, the taper accuracy is a straightness of 0.003 to 0.007 mm and an angle difference of −0.0.
It shows a very good result of 7 degrees to -0.03 degrees, and the surface roughness to be cut is also good, and particularly, the present invention example 1 and the present invention example 19
Has a good straightness of 0.005 mm or less. In Inventive Example 21, a slight amount of welding was found on the first flank, and the taper accuracy was slightly inferior with a straightness of 0.009 mm and an angle difference of −0.12 degrees.

(Embodiment 5) As Embodiment 22 of the present invention, an end mill similar to that of Embodiment 1 of the present invention was manufactured, and then subjected to polishing treatment by shot blasting.
The same cutting test was performed. As a result, Example 22 of the present invention
Shows no deposits on the flank surface after cutting, has a taper accuracy of 0.002 mm, an angle difference of -0.01 degrees, and has an excellent surface roughness of Ry of 0.3 μm. Even when compared with Invention Example 1, good results were obtained.

(Example 6) As Example 23 of the present invention, a taper radius end mill having the same specifications as Example 1 of the present invention shown in FIG. 8 and having a corner R blade with a radius of 0.2 mm at the end corner portion of the end of the end mill is provided. I made it. As Example 24 of the present invention,
A tapered ball end mill having the same specifications as those of Example 1 of the present invention shown in FIG. Invention Example 2
The same cutting test and evaluation as in Example 1 were performed on Nos. 3 and 24. As a result, the invention examples 23 and 24 are in a more stable cutting state as compared with the invention example 1, and the invention example 23 is
As shown in FIG. 10, the taper accuracy is a straightness of 0.002 m.
m, the angle difference was −0.02 degrees, and the surface roughness to be cut was Ry as good as 0.3 μm.

(Embodiment 7) Inventive Example 25 has the same specifications as Inventive Example 1 and a blade length of 20 mm.
No. 30, with the same specifications as Example 23 of the present invention, the blade length is 20 mm,
The radius of the corner R blade is 0.05 mm, 0.1 mm,
Manufacture 0.2mm, 0.3mm, 0.4mm,
A cutting test and evaluation were performed. The cutting data used was prehardened steel with a hardness of HRC38 as the work material, and the rotation speed was 16000.
min ^-1 , table feed speed 500 mm / min, cutting depth 0.016 mm / turn in the axial direction of the tool, and using a water-soluble cutting fluid, the depth of the rib groove is 20 mm, that is,
The reciprocating rib groove of the blind groove was cut at 1250 times in the tool axial direction. As a result, in Invention Example 25, a slight chattering was observed on the surface to be cut, and the taper accuracy was a straightness of 0.01.
mm, the angle difference was -0.14 degrees, and minute chipping and local wear were observed at the end corners after the test.
In the invention examples 26 to 30, no chattering surface was observed at all, and in the invention examples 27 to 29, the taper accuracy was 0.003 mm in straightness.
A very good taper accuracy of 0.005 mm and an angle difference of −0.04 degrees to −0.07 degrees was obtained. Inventive Example 26,
A small amount of local wear was observed in the end corner portion after the cutting test, the invention sample 30 had a slightly larger cutting resistance during the cutting test, and the taper accuracy was slightly inferior to the invention examples 27 to 29. Became.

[0017]

EFFECTS OF THE INVENTION By applying the present invention, it is possible to provide a taper end mill for rib groove machining which can obtain an excellent taper accuracy of rib groove with a straightness within 0.01 mm and within ± 0.15 degrees. Became.

[Brief description of drawings]

FIG. 1 shows a side view of Example 1 of the present invention.

FIG. 2 is a cross-sectional view of the blade of FIG.

FIG. 3 shows a side view of Conventional Example 2.

FIG. 4 shows a cross-section perpendicular to the axis of the blade of FIG.

FIG. 5 illustrates a processed shape.

FIG. 6 shows the test results of Example 1 of the present invention.

FIG. 7 shows test results of Conventional Example 2.

FIG. 8 shows a side view of Example 23 of the present invention.

FIG. 9 shows a side view of Example 24 of the present invention.

FIG. 10 shows the test results of Inventive Example 23.

[Explanation of symbols]

1: taper angle 2: Peripheral blade 3: First flank 4: Second flank 5: First clearance angle 6: Second clearance angle 7: 1st flank width 8: Rib groove taper angle 9: Reference line 10: Measurement line 11: Average taper angle

Claims (5)

[Claims] 1. A taper end mill for processing a rib groove,
The outer peripheral blade has two or more blades and forms a taper shape, and a first flank and a second flank are provided from the ridgeline of the outer peripheral blade toward the rear in the tool rotation direction, and the first flank of the first flank is provided. A taper end mill for machining a rib groove, wherein the angle is 0.5 degrees or more and 7 degrees or less, and the second clearance angle of the second flank is 10 degrees or more and 20 degrees or less. 2. The tapered end mill for rib groove machining according to claim 1, wherein the first flank has a center line average surface roughness Ra of 0.3 μm or less. 3. The tapered end mill for machining a rib groove according to claim 1, wherein the first flank has A
l, Si, B, carbides, carbonitrides, nitrides, oxides, borides and boron carbides of metals of groups 4a, 5a and 6a of the periodic table,
One or more hard coatings selected from the group consisting of hard boron nitride, hard carbon, and solid solutions or mixtures thereof, and a coating having a thickness of 0.2 to 10 μm. A characteristic taper end mill for rib groove processing. 4. The taper end mill for rib groove machining according to claim 3, wherein the irregularities on the coating surface are removed by polishing. 5. The taper end mill for rib groove machining according to claim 1, wherein the end mill is a taper radius end mill or a taper ball end mill.