JP3935450B2 - Bottom finishing end mill - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an end mill for finishing the bottom surface of a seal groove such as an O-ring.
[0002]
[Prior art]
When performing bottom finish cutting of a bottom surface, particularly a seal groove such as an O-ring of a vacuum apparatus, the bottom surface is finished by one feed in one direction.
[Patent Document 1]
Japanese Unexamined Patent Publication No. 2000-42822 (page 4, FIG. 2)
[0003]
Patent Document 1 is composed of a secondary cutting edge in which a bottom cutting edge is continuously formed from a primary cutting edge and a primary cutting edge on the outer peripheral edge corner side as an end mill for the purpose of improving the bottom surface roughness. An end mill is described in which the primary cutting edge angle α is reduced by 3 ′ to 30 ′.
[0004]
[Problems to be solved by the invention]
When finishing the bottom surface of a seal groove such as an O-ring of a vacuum device, a cutter mark that crosses the groove width may cause vacuum leakage. Therefore, use a grindstone or sandpaper to remove the cutter mark on the bottom surface of the groove. Is forced to work and spends a lot of work time. Also in the end mill described in Patent Document 1, a cutter mark is generated on the bottom surface of the groove due to a change in the end mill corner portion or a medium / low gradient, and there is a problem with the cutter mark on the bottom surface of the groove.
[0005]
[Object of the present invention]
The present invention has been made in order to solve the above-described problems. When the bottom finish cutting of a seal groove such as an O-ring is performed, a good surface roughness is obtained and a cutter mark that crosses the groove width is obtained. An object of the present invention is to provide a bottom finishing end mill that suppresses generation.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an end mill having a plurality of bottom blades, wherein the bottom blade is an equal bottom blade, a center cut blade, and the end mill is viewed from the side, and the bottom blade is straight. And it is formed in a convex shape with the end on the axial center side protruding most, the convex portion is provided with a convex shape that exceeds 0 and 0.05 mm or less , and the bottom blade is a surface in which the convex shape continues in the feed direction, Chips generated during one rotation of the end mill are bottom finishing end mills that start from the axial center side, are sequentially generated toward the outer periphery of the bottom blade, and the chips are discharged upward and outward . Next, in the side view of the end mill, the bottom blade has a convex curve shape, and the center portion of the bottom blade protrudes most, and the convex portion exceeds 0 and is 0.05 mm or less. This is an end mill for bottom finishing.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, since the cutter mark is reduced or not formed, first, by making the bottom blade an equal bottom blade and a center cut blade, the cutting state by the bottom blade is made regular, and the work surface is stabilized. Since there is a series of bottom blades from the outer peripheral end to the vicinity of the end mill axis, almost no part of the bottom blade due to the occurrence of cutter marks can be eliminated. Second, when the end mill is viewed from the side, the bottom edge is formed in a convex shape so that the surface cut at the corner is scraped off by the bottom edge on the axis side where the cutting depth is larger than that at the corner. The surface becomes convex in the direction, and scratches due to corners or the like, that is, generation of cutter marks can be almost eliminated. Thirdly, by setting the convex portion to more than 0 and 0.05 mm or less, the depth tolerance of the seal groove of the O-ring can be sufficiently cleared, and further, the entire bottom blade can be involved in cutting. And the formation of cutter marks can be reduced or eliminated. More preferably, it is 0.03 mm or less.
[0008]
Next, by providing a center-remaining portion at the shaft center portion of the end mill, the cutting edge strength at the shaft center portion can be ensured. In the case where no center-remaining portion is provided, the strength of the bottom blade is lowered, the wear of the bottom blade proceeds quickly, and the finished surface is roughened. The reason why the width of the remaining part is 0.2 mm or less is that when it exceeds 0.2 mm, the cutting resistance increases, and the cutter mark is conspicuous in the center of the groove formed by both ends of the remaining part, and the cutting surface roughness decreases. Because.
[0009]
Furthermore, in the side view of the end mill, the end mill end of the end blade is protruded most with respect to the line connecting the outer peripheral end of the bottom blade and the end mill axis, so that the end mill is generated during one rotation. The scraps start from the remaining part of the heart and are sequentially generated toward the outer periphery of the bottom blade. The scraps flow smoothly in the direction of the outer periphery and upward, and welding to the cutting blade and deep cutter marks due to the constituent cutting edges can be suppressed. Needless to say, the end mill performance is further improved by using a super-hard alloy or cermet as the end mill material, or coating with a high hardness and high lubricity film. Further, by imparting a radius to the outer peripheral end of the bottom blade, the strength of the end corner portion is obtained, and the effect of suppressing the generation of burrs at both width ends of the groove bottom surface is also obtained. Hereinafter, the present invention will be specifically described based on examples.
[0010]
Example 1
Example 1 of the present invention is a solid solid end mill with a center cut and equal bottom blade having a blade diameter of 10 mm and two linear bottom blades 1 as shown in FIGS. This is an example in which the tip protrusion amount 2 is 0.02 mm, the center portion 3 is provided in the end mill shaft center portion, and the width 4 of the center portion is 0.1 mm in the bottom view of the end mill. For comparison, as a conventional example 2, a bottom blade-shaped end mill described in Patent Document 1 was used. Using Example 1 of the present invention and Conventional example 2, a finish cutting test was performed on the bottom surface of a groove of an aluminum alloy that was roughly machined into a groove width of 10.1 mm and a depth of 7 mm. The cutting conditions were a cutting speed of 100 m / min, a feed amount per tooth of 0.05 mm, and a cutting amount in the Z direction of 0.1 mm, and the cutter mark and the surface roughness were evaluated. As a result, in Example 1 of the present invention, a surface having a processed surface roughness of 1.0 μm at the maximum surface roughness Rz and no cutter mark was obtained, and no cutter mark was generated even after 10 m of cutting. Conventional example 2 has a cutter mark corresponding to the step portion of the blade diameter and the primary and secondary cutting edges, the maximum surface roughness Rz is 2.9 μm, and welding is performed at several locations from the point where the cutting length is too much 2 m. Alternatively, a scratched cutter mark having a depth of 8.5 μm due to the constituent blade edge was generated.
[0011]
(Example 2)
With the same specifications as Example 1 of the present invention, the amount of the protrusion at the tip was 0 mm as Comparative Example 3, 0.005 mm as Invention Example 4, 0.01 mm as Invention Example 5, 0.03 mm as Invention Example 6 The end mill was changed to 0.04 mm as Invention Example 7, 0.05 mm as Invention Example 8, and 0.06 mm as Comparative Example 9, and the same tests and evaluations as in Example 1 were performed. As a result, in Examples 4 to 8 of the present invention, no cutter mark was generated, and a good surface roughness of 2.5 μm or less was obtained with a maximum surface roughness Rz, and the maximum surface roughness was achieved in a short time with a rubber grindstone in the subsequent process. The thickness Rz can be finished to 1.0 [mu] m or less. In particular, Examples 4 to 6 of the present invention were good with a maximum surface roughness Rz of 2.0 [mu] m or less. Further, in Comparative Example 3, a cutter mark is generated by the edge of the outer edge of the bottom blade, and in Comparative Examples 3 and 9, the maximum surface roughness Rz is 4.0 μm or more. In particular, Comparative Example 9 has a high O-ring groove height. The tolerance is also out of range.
[0012]
(Example 3)
The same specifications as in Example 1 of the present invention, the width of the remaining portion is 0 mm as Example 10 of the present invention, 0.05 mm as Example 11 of the present invention, 0.15 mm as Example 12 of the present invention, 0.20 mm as Example 13 of the present invention, Inventive Example 14 with a thickness of 0.25 mm was manufactured and the same test as in Example 1 was performed. As a result, in the inventive examples 11 to 13, no cutter mark is generated, and a good surface roughness with a maximum surface roughness Rz of 2.0 μm or less is obtained. In particular, the inventive example 11 is an inventive example 1 In the same manner as above, an excellent surface roughness of 1.0 μm was obtained at the maximum surface roughness Rz. In Example 10 of the present invention, the width of the remaining portion is 0 mm, that is, there is no leftover, the strength at the axial center is weak, and chipping occurs at a cutting length of 6 m. Although it does not cross, the cutting surface in the center of the groove was crumpled after the cutting length of 7 m, and the surface roughness was rough.
[0013]
Example 4
As Example 15 of the present invention, it has the same specifications as Example 1 of the present invention, has a convex curve shape in a side view of the end mill, and protrudes most at the center of the bottom blade with respect to the line segment connecting the outer peripheral end of the bottom blade and the end mill axis. The same test as in Example 1 was performed. Since Example 1 of the present invention is a straight bottom blade, the end mill side end of the bottom blade protrudes most from the line connecting the outer peripheral end of the bottom blade and the end mill axis in a side view of the end mill. ing. As a result, compared with Example 1 of the present invention, Example 15 of the present invention has poor chip flow, and welding is observed on the bottom blade near the shaft center. Some welding occurred, and the surface roughness started to deteriorate.
[0014]
【The invention's effect】
By applying the present invention, a bottom finishing end mill that can obtain a good surface roughness and suppress the generation of a cutter mark across the groove width when the bottom finishing cutting of a seal groove such as an O-ring is performed. Was able to provide.
[Brief description of the drawings]
FIG. 1 shows a side view of Example 1 of the present invention.
FIG. 2 shows a bottom view of FIG.
[Explanation of symbols]
1 Bottom blade 2 Tip protrusion 3 Heart leaving part 4 Heart leaving part width

Claims (3)

In an end mill having a plurality of bottom blades, the bottom blade is an equal bottom blade, a center cut blade, and the bottom blade is straight and has a convex shape with the end on the axial center side protruding most when viewed from the side of the end mill. The convex part is provided with a convex portion that exceeds 0 and is 0.05 mm or less , the bottom blade is a surface in which the convex shape continues in the feed direction, and chips generated during one rotation of the end mill are: A bottom finishing end mill characterized in that it starts from the axial center side and is sequentially generated toward the outer periphery of the bottom blade, and chips are discharged upward and outward .   2. The bottom finishing end mill according to claim 1, wherein the axial center portion of the end mill is provided with a center leaving portion, and the width of the center leaving portion is 0.2 mm or less. In an end mill having a plurality of bottom blades, the bottom blade is an equi-bottom blade, a center cut blade, and the bottom blade has a convex curve shape in the side view of the end mill, and protrudes most at the center of the bottom blade. The convex portion has a surface exceeding 0 and 0.05 mm or less , and the bottom blade has a surface in which the convex shape continues in the feed direction, and the chips generated during one rotation of the end mill are on the axial side. A bottom finishing end mill characterized in that it starts from the top and is sequentially generated toward the outer periphery of the bottom blade, and chips are discharged upward and outward .

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