Technical Field
[0001] The present invention generally relates to cutting tools and a method for treating a
surface thereof, and more particularly, to a cutting tool and a method for treating a surface
thereof, in which the surface (a coating layer) of the cutting tool is primarily blasted and then
secondarily brushed so that the cutting tool has superior resistance to chipping while cutting a
workpiece, and superior durability through improvement in abrasion resistance and toughness.
Background Art
[0002] A cutting tool is used to process cast iron, carbon steel, alloy steel, etc. The cutting tool,
such as an insert, performs cutting when in contact with a workpiece. Generally, a cutting tool,
e.g. an insert, uses a cemented carbide, made by mixing cobalt (Co) with tungsten carbide
(WC) and sintering the mixture, or a Ti-group carbo-nitride cermet, as its base material which
has a hard coating layer for abrasion resistance formed on its surface. The coating layer is
formed by coating a compound such as a metallic oxide (e.g., AI203), a carbide (e.g., TiC), and
the like using a chemical vapor deposition (CVD) method or a physical vapor deposition (PVD)
method.
[0003] For example, U.S. Patent No. 6,007,909 suggests a cutting tool in which a coating layer
having a thickness of 1 ~ 20μm is formed on a Ti-group carbo-nitride cermet base material, and
U.S. Patent No. 6,183,846 suggests a cutting tool where an inner layer with a thickness of 0.1 ~5
μm, consisting of a carbide, a nitride, a carbo-nitride, a carbo-oxide, a carbonitrogen oxide or a
boronitride of Ti, an intermediate layer with a thickness of 5~50 μm consisting of Al203, and an
outer layer with a thickness of 5~100 μm, consisting of a carbide, a nitride, a carbo-nitride, a
carbo-oxide, a carbonitrogen oxide or a boronitride of Ti are formed on a surface of a cemented
carbide or cermet base material. Korean Patent Registration No. 0847715 suggests a cutting
insert including a coating layer where a single layer of a carbide, a nitride, or an oxide, a
multi-layer thereof, and/or a crossed layer thereof are injected on a cermet base material
including a Co and/or Ni binder phase. Korean Patent Publication No. 10-2004-0084760
discloses a coated cutting insert where a TiCxNyOz layer (0.7 ≤ x+y+z ≤1) and an Al203 layer
are formed on a cemented carbide base material.

[0004] The coating layer is formed by injecting crystalline particles, and some of the particles
protrude, resulting in an uneven surface. Consequently, the outermost surface of the cutting tool
becomes rough due to the formation of pointed protrusions. Such a phenomenon becomes
more severe as the thickness of the coating layer increases. The phenomenon is particularly
severe in ceramic coatings such as Al203. Moreover, this phenomenon is common in coating
layers regardless of the type of material forming the coating layers. A cutting tool having a rough
surface is subjected to non-uniform stress while cutting a workpiece, and as a result chipping is
likely to occur at the cutting portion and the coating layer or the base material may be damaged,
causing the effectiveness of the tool to be reduced.
[0005] In order to improve the rough surface of cutting tools, a technique for performing
surface treatment on the coating layer has been attempted. For example, Korean Patent
Registration No. 0187564 discloses a surface treatment method in which a surface (coating
layer) of a coated cutting tool is rubbed with an abrasive cloth or brush-honed.
[0006] However, the disclosed surface treatment methods above may provide an even surface
to some extent, but the provided surface has poor resistance to chipping, low abrasion
resistance, and low toughness because it is not sufficiently smooth and flat.
[Prior Patent Document 1] U.S. Patent No. 6,007,909
[Prior Patent Document 2] U.S. Patent No. 6,183,846
[Prior Patent Document 3] Korean Patent Registration No. 0847715
[Prior Patent Document 4] Korean Patent Publication No. 10-2004-0084760
[Prior Patent Document 5] Korean Patent Registration No. 0187564
Disclosure
Technical Problem
[0007] It is the object of the present invention to solve the foregoing problems of the prior art
and to provide a method for treating a surface of a cutting tool so it has superior resistance to
chipping while cutting a workpiece, and has superior durability through improvement of abrasion
resistance and toughness. The present invention also provides a cutting tool whose surface is
treated using the above method.

[0008] In order to achieve the foregoing object, the present invention provides a method for
treating a surface of a cutting tool, comprising blasting the surface of the cutting tool using a
granular abrasive and brushing the blasted surface of the cutting tool.
[0009] The abrasive may be comprised of one or more elements selected from a group
consisting of mineral particles, ceramic particles, and metal particles. According to a preferred
embodiment of the present invention, the blasting may be performed by injecting the abrasive
onto the surface of the cutting tool at a pressure of 1.0 ~ 2.5 bar for 5 ~ 30 seconds. The
blasting may also be performed by injecting a mixture of the granular abrasive and water onto
the surface of the cutting tool. Preferably, the abrasive has a density of 0.8 ~ 1.5 kg//.
[0010] The brushing may be performed for 50 ~ 200 seconds while either one or both a brush
and the cutting tool is being rotated at a speed of 60~ 120 rpm. Preferably, a lubricant is applied
to the brush. The lubricant may include solid particles having a size of 0.5 -10 μm.
[0011] Moreover, the present invention also provides a cutting tool whose surface is treated by
the method.
Advantageous Effects
[0012] According to the present invention, the surface condition of the cutting tool is improved
by a two-step surface treatment including blasting (primary surface treatment) and brushing
(secondary surface treatment). Therefore, the cutting tool has superior resistance to chipping
while cutting a workpiece and has excellent durability by means of improvement in abrasion
resistance and toughness. Moreover, the surface treatment time for producing equivalent
surface quality is remarkably reduced compared to other conventional surface treatment
methods.
Description of Drawings
[0013] FIG. 1 is an exemplary perspective view of a brushing device used in the present
invention.

[0014] FIGs. 2 and 3 illustrate enlarged pictures of surfaces of corner portions of cutting tool
specimens which are surface-treated according to comparison examples and an embodiment of
the present invention.
[0015] FIGs. 4 and 5 illustrate enlarged pictures of surfaces of crater portions of the cutting
tool specimens which are surface-treated according to the comparison examples and the
embodiment of the present invention.
[0016] FIGs. 6 and 7 illustrate enlarged pictures of surfaces of grinding portions of the cutting
tool specimens which are surface-treated according to the comparison examples and the
embodiment of the present invention.
[0017] FIG. 8 illustrates cross-sectional pictures of surfaces of the cutting inserts according to
comparison examples 5 and 6.
[0018] FIG. 9 illustrates pictures of surfaces of a workpiece cut by using the cutting tool
specimens which are surface-treated according to the embodiment of the present invention.
[0019] FIG. 10 illustrates measurement standards for surface roughness of the workpieces
according to the present invention.
Mode for Invention
[0020] Hereinafter, the present invention will be described in more detail.
[0021] In the present invention, a cutting tool which is subject to surface treatment is typically a
cutting insert mounted on a tool holder. A cutting tool contacts a workpiece such as cast iron,
carbon steel, alloy steel, etc., and includes a hard coating layer coated onto a base material for
abrasion resistance. The base material and the coating layer include commonly used materials.
For example, the base material may be selected from cemented carbide made by mixing cobalt
(Co) with tungsten carbide (WC) and sintering the mixture, and a cermet including a Ti-group
carbo-nitride phase, or Co, Ni, W and/or Mo. The cermet may include one or more additional
elements selected from Ta, Nb, V, Zr, Hf, Cr, and the like.
[0022] The coating layer may be coated onto a surface of the base material by means of

chemical vapor deposition (CVD) or physical vapor deposition (PVD), and may include an oxide,
a carbide, a nitride, a carbo-nitride, a nitric oxide, or a nitride carbonate including one or more
elements selected from Al, Ti, Zr, and Hf, or a mixture thereof. More specifically, for example,
the coating layer may include one or more elements selected from alpha (a)-AI203, TiN, AIOxNy
(0 ≤ x ≤ 1, 0 ≤y ≤ 1), HfN, TiCxNy (0 ≤ x ≤ 1, 0 ≤ y ≤ 1), and TiCxNyOz (0≤x≤1,0≤y≤1,0≤z
≤ 1). The coating layer may be a single layer or a multi-layer including two or more layers.
Although it is not particularly limited, in the case of a multi-layer coating layer, the coating layer
includes, for example, a TiN layer formed on the surface of the base material and the alpha
(α)-AI203 layer formed on the TiN layer, in which the α-AI2Q3 layer is the outermost layer. The
thickness of the coating layer may be 3.0~ 50 μm, but is preferably 10~ 30 μm. The coating layer
is etched by a method for treating a surface of a cutting tool (blasting and brushing) according to
the present invention as described below, preferably with an etching thickness of 0.5 - 2.0 μm.
[0023] The method for treating the surface of the cutting tool according to the present
invention includes at least a primary surface treatment step of blasting the surface of the cutting
tool, i.e., a surface of the coating layer (outermost layer), and a secondary surface treatment
step of brushing the blasted surface of the cutting tool The blasting step (primary surface
treatment) and the brushing step (secondary surface treatment) are consecutively performed.
That is, the surface (coating layer) of the cutting tool is primarily blasted, after which the blasted
surface is secondarily brushed.
[0024] In the present invention, the blasting step is performed by injecting a granular abrasive
onto the surface (coating layer) of the cutting tool at high pressure and may include a dry
method and a wet method. More specifically, the blasting step may be carried out by a dry
method in which the granular abrasive is injected onto the surface of the cutting tool by using
high-pressure air as a propellant or by a wet method in which a mixture of the granular abrasive
and water is injected onto the surface of the cutting tool at high pressure. Preferably, the
blasting step is conducted by the wet method because it is advantageous in terms of work
environment, roughness, and uniformity. The abrasive may be one species or a mixture of at
least two species selected from a group consisting of mineral particles (natural sand, silica, etc.),
ceramic particles (alumina particles, etc.), metal particles (cast iron, alloy steel particles, etc.),
and the like.
[0025] The size of the granular abrasive particles (grain size distribution) is preferably 30p ~

900 μm. If the abrasive particles are too small, e.g., their size is less than 30μm, good flatness
cannot be expected and too much time is taken to process the tool. On the other hand, if the
abrasive particles are too large, e.g., their size exceeds 900 μm, surface roughness may
become severe and the coating layer may be cracked or damaged. The cutting tool, such as an
insert, has protruding portions (comers, edge portions, and the like), which may be
disadvantageously etched if the abrasive is large in size. Moreover, the granular abrasive may
be a mixture of small-diameter particles of 30 ~75 μm and large-diameter particles of 75 - 900
μm at a ratio of 1: 0.5 - 2.
[0026] When the blasting step is performed by the wet method, the density of the abrasive is
preferably 1.0~1.5 kg// (quantity of the abrasive included in a 1 / mixture of the abrasive and
water). The abrasion efficiency may be reduced and too much time may be taken to process the
tool if the abrasive density is less than 1.0 kg//, whereas superior injection cannot be expected if
the abrasive density exceeds 1.5 kg//. The density of the abrasive is preferably 1.0 -1.2 kg//.
[0027] For the wet blasting step, the injection pressure of the abrasive is preferably 1.0 ~2.5
bar, and more preferably 1.4 ~ 2.0 bar. If the injection pressure is less than 1.0 bar, it is difficult
to perform etching. On the other hand, if the injection pressure exceeds 2.5 bar, the etch rate
increases, thereby removing the coating layer or causing damage to the coating layer. Under
such pressure conditions, the blasting step (abrasive injection at high pressure) is preferably
performed for 5 ~30 seconds. For example, in the case of a commonly used CNMG 12type
cutting insert, it is desirable to perform the blasting step for 10~15 seconds at an injection
pressure of 1.4 - 2.0 bar.
[0028] The blasting step is performed by injecting the abrasive onto a plurality of cutting tools
arranged on a conveyer, from a blasting gun installed at a predetermined angle on the conveyer,
where the conveyor moves horizontally (in an x direction on an x-y plane) and the blasting gun
repetitively moves vertically (in a y direction on the x-y plane). The conveyor speed is preferably
120-200 mm/min. The etching is too excessive for a conveyor speed less than 120 mm/min, but
the etching is insufficient for a conveyor speed exceeding 200 mm/min. The blasting gun may
repetitively move at a speed of 4500 - 5500 mm/min. In other words, the cutting tools move
horizontally (in an x direction on an x-y plane) at the conveyor speed of 120-200 mm/min, while
a blasting gun installed above the conveyor repetitively moves vertically (in a y direction on the

x-y plane) at the speed of 4500~ 5500 mm/min. By performing the blasting step under such
operating conditions, excellent flatness can be achieved. The injection may be performed with
the blasting-gun at an angle in the range of 45 ± 20 degrees. By injecting the abrasive in such a
way, a top surface and a side surface of the cutting tool can be uniformly blasted. Thereafter,
the cutting tool is turned over to blast a bottom surface of the cutting tool.
[0029] When the blasting step is performed by the dry method, the injection pressure of the air
and the abrasive is preferably 1.0 ~2.5 bar, and more preferably 1.8 ~2.0 bar. Under such
pressure conditions, the blasting step is preferably performed for 5~30 seconds. The
conveyor speed is preferably 150-500 mm/min. If the injection pressure is too low or the
conveyor moves too slowly, it is difficult to perform etching. On the other hand, if the injection
pressure is too high or the conveyor moves too fast, the etch rate becomes excessive, thereby
removing the coating layer or causing damage to the coating layer to an unacceptable extent.
[0030] The brushing step may be performed by a general brushing method (brush honing).
The brushing step may be carried out by using a brushing device as illustrated in FIG. 1.
Although the brushing step may be performed by rotating at least one of a brush and the cutting
insert by using the brushing device described below, it is desirable to perform the brushing step
by simultaneously rotating both the brush and the cutting insert.
[0031] Referring to FIG. 1, the brushing device includes a support plate 10, and a disc-shaped
carrier 20 installed on the support plate 10. A plurality of carriers 20 may be installed on the
support plate 10 and rotate clockwise (forward rotation) and/or counterclockwise (reverse
rotation). FIG. 1 illustrates a state where eight (8) carriers 20 installed on the support plate 10
rotate clockwise and counterclockwise. A plurality of cutting inserts is mounted on the carrier 20.
For example, 36 cutting inserts may be mounted on one carrier 20. The brushing device also
includes a disc-shaped brush plate 30 installed above the carrier 20. A plurality of brushes 32
are arranged under the brush plate 30. The brush plate 30 may have a diameter of 500 mm,
and the carrier 20 may have a diameter of 138 mm. The brush plate 30 is rotatably installed,
and is preferably installed so as to rotate counterclockwise (reverse rotation) as well as
clockwise (forward rotation). For example, the carrier 20 may repeat rotation clockwise (forward
rotation) and counterclockwise (reverse rotation) and the brush plate 30 installed above the
carrier 20 may rotate in one direction (e.g., clockwise), thereby improving brushing efficiency.
[0032] In a preferred embodiment, a lubricant is applied to the brush 32 for efficient brushing.

The lubricant is preferably a paste-phase composition including oil and solid particles (abrasive).
For example, the solid particles may be silica or diamond. The solid particles may have a size of
0.5~10μm. The solid particles may be included in the paste-phase lubricant by 0.2~5 weight %,
e.g., 2~50 g of solid particles are mixed with 1kg of a lubricant.
[0033] The brushing step may be performed by rotating the brush 32 at a speed of 60 ~120
rpm. In other words, the rotation speed of the brush plate 30 is 60 ~120 rpm. If the rotation
speed of the brush 32 is less than 60 rpm, too much time is taken to smooth the surface,
whereas if the rotation speed of the brush exceeds 120 rpm, the brush 32 may be prematurely
worn out. The brushing step is preferably performed for 50 ~200 seconds at the rotation speed
of the brush 32. It is difficult to obtain a smooth surface with a brushing time less than 50
seconds. On the other hand, with a brushing time exceeding 200 seconds, the surface becomes
smooth but leads to excessive abrasion of the coating layer due to brushing and too much
power may be required. It is preferable that the carrier 20 installed under the brush plate 30
repeat forward rotation and reverse rotation during rotation of the brush plate 30 where the
carrier 20 rotates forward once for 25~100 seconds and then rotates in reverse once for 25
~100 seconds. The rotation speed of the carrier 20, i.e., the rotation speed of the cutting tool is
preferably 60 -120 rpm.
[0034] According to the present invention, the surface condition of the cutting tool is improved
by the above-described two-step consecutive surface treatments (blasting and brushing). More
specifically, the flatness (roughness) of the surface of the cutting tool is improved by primary
blasting, and the blasted surface becomes smooth by secondary brushing performed after
primary blasting. If only blasting is performed, the flatness may be improved, but the surface is
not smooth. If only brushing is performed, the surface becomes smooth, but the flatness is
reduced and too much time is taken. Here, if the surface is treated for a long time to achieve an
equivalent flatness with only brushing, there is the problem of removing the outer coating layer
due to excessive etching. If brushing is performed and then blasting is performed, a smooth
surface cannot be obtained. Therefore, blasting is performed first and then brushing is
performed. By doing so, the surface condition of the cutting tool is improved, thereby
manufacturing a cutting tool having superior resistance to chipping while cutting a workpiece
and having excellent durability through improvement of abrasion resistance and toughness. In
addition, the treatment time required for an improved surface can be remarkably reduced and
the surface quality such as surface roughness is much improved. The cutting tool is generally

used while inserted into a cutting tool holder. According to the present invention, close contact
with the holder is enhanced by surface improvement, thereby preventing damage to the cutting
tool or the holder.
[0035] Hereinafter, embodiments of the present invention will be described in further detail.
The following embodiments are provided only to facilitate understanding of the present invention
and do not limit the technical scope of the present invention.
Embodiments 1-3
[0036] A commonly used CNMG 12type cutting insert, having an Al203 layer of 15 p coated
on a cemented carbide base material, was used as a target specimen on which wet sand
blasting and brushing were consecutively performed.
Wet sand blasting
[0037] By using a wet sand blasting device, a surface of the cutting insert (CNMG 12type) was
wet-sand-blasted under the conditions shown in Table 1. As an abrasive, alumina particles of a
Treibather product known as Alodur were used in the form of a mixture of alumina particles of
170 mesh (90 p) and those of 230 mesh (63 p) at a weight ratio of 1 : 1. The density of the
abrasive was 1.01 kg// (quantity of alumina included in a 1 / mixture of alumina and water).


[0038] The wet-sand-blasted specimen was brushed by using a brushing device under the
conditions shown in Table 2. The brushing device has a structure as illustrated in FIG. 1. The
diameter of the carrier 20 was 138 mm and the diameter of the brush plate 30 was 500 mm. in
Embodiment 1, the carrier 20 rotated forwards once for 50 seconds and then rotated in reverse
once for 50 seconds. The brush plate 30 rotated forwards, and the brush 32 had a depth of 0.6
mm.

Comparison Example 1
[0039] A commonly used CNMG 12type cutting insert, having an Al203 layer of 15 μm coated
on a cemented carbide base material, was used as a target specimen for Comparison Example
1, whereby a coating surface is neither blasted nor brushed (not treated).
Comparison Example 2
[0040] A commonly used CNMG 12type cutting insert, having an Al203 layer of 15 μm coated
on a cemented carbide base material, was used as a target specimen for Comparison Example
2, whereby the coating surface is brushed only (not wet-sand-blasted) in the same manner as in
Embodiment 1. Brushing time was 100 seconds with forward rotation of 50 seconds and
reverse rotation of 50 seconds.

[0041] A commonly used CNMG 12type cutting insert, having an Al203 layer of 15 μm coated
on a cemented carbide base material, was used as a target specimen for Comparison Example
3, whereby the coating surface is wet-sand-blasted only (not brushed) in the same manner as in
Embodiment 1.
Comparison Example 4
[0042] The specimen of this Comparison Example was the same as in Embodiment 1, except
that brushing was performed first, and then blasting followed.
Comparison Example 5
[0043] The specimen of this Comparison Example was the same as in Comparison Example 2,
except that brushing was performed for 300 seconds with forward rotation of 150 seconds and
reverse rotation of 150 seconds.
Comparison Example 6
[0044] The specimen of this Comparison Example was the same as in Comparison Example 2,
except that brushing was performed for 500 seconds with forward rotation of 250 seconds and
reverse rotation of 250 seconds.
[0045] Pictures of surfaces of the specimens according to Embodiment 1 and Comparison
Examples 1 6 are illustrated in FIGs. 2 through 7. FIGs. 2 and 3 illustrate enlarged pictures (x
3000) of surfaces of corner portions of the specimens, FIGs. 4 and 5 illustrate enlarged pictures
(x 3000) of surfaces of crater portions of the specimens, and FIGs. 6 and 7 illustrate enlarged
pictures (x 3000) of surfaces of grinding portions of the specimens. FIG. 8 is a cross-sectional
picture of Comparison Examples 5 and 6.
[0046] As illustrated in FIGs. 2 through 7, Embodiment 1 which received blasting and brushing
consecutively performed according to the present invention provides a smooth surface with and
superior-flatness (roughness) when compared to Comparison Example 1 where no treatment

was performed, Comparison Example 2 where only brushing was performed for 100 seconds,
Comparison Example 3 where only wet-sand blasting was performed, and Comparison Example
4 where brushing was performed first and then blasting was performed. In Comparison
Examples 5 and 6, when only brushing was performed for longer periods for the purpose of
obtaining improved surface quality, there was a problem of the coating layers being removed by
excessive etching, particularly on the edge portions, due to a longer treatment time as shown in
FIG. 8.
[0047] By using the specimens according to Embodiment 1 and Comparison Examples 1 ~6,
cutting performance was evaluated using an automobile brake drμm (HB 170) as a workpiece.
The cutting performance was evaluated by counting the number (pcs) of workpieces processed
until failure of the specimen occurred. The evaluation results, together with the cutting
conditions, are shown in Table 3. FIG. 9 illustrates pictures of the workpiece after failure.

[0048] As shown in Table 3 and FIG. 9, Embodiment 1, where blasting and brushing were
consecutively performed according to the present invention, provides improved abrasion
resistance and toughness (durability) when compared to Comparison Example 1 where no
treatment is received, Comparison Example 2 where only brushing was performed, Comparison
Example 3 where only wet-sand blasting was performed, Comparison Example 4 where
brushing was performed first and then blasting was performed, and Comparison Examples 5
and 6 where only brushing was performed for longer periods of time, thereby preventing
breakage even when more workpieces were processed. When comparing Comparison

Examples 2, 5, and 6 where only brushing was performed, as shown in FIGs. 2 through 7 and
Table 3, although the surface roughness improved as brushing time increased, when brushing
is performed for a longer period of time in excess of 200 seconds, cutting performance
measured by the number of processed workpieces deteriorated due to abrasion concentrated
on the protruded portions, thereby removing the coating layer on the cutting edges.
[0049] Table 4 below shows the measured surface roughness of the workpieces, which were
cut by insert specimens prepared in Embodiment 1 and Comparison Examples 2 through 4. FIG.
10 illustrates measurement standards for surface roughness. In Table 4, Ra indicates a center
line average roughness, Rmax indicates a maximμm height, and Rz indicates a ten-point
average roughness (see FIG. 10).

[0050] As shown in Table 4, Embodiment 1, where blasting and brushing were consecutively
performed according to the present invention, provides improved surface roughness of the
workpieces when compared to Comparison Example 1 where no treatment is received,
Comparison Example 2 where only brushing was performed, Comparison Example 3 where
only wet-sand blasting was performed, and Comparison Example 4 where brushing was
performed first and then blasting was performed. In addition, Table 4 indicates that the surface
roughness of the workpieces finished by Comparison Example 3 where only wet-sand blasting
was performed is much improved compared with that of Comparison Example 2 where only
brushing was performed. This result implies that performing sand blasting, regardless of
whether brushing is performed, is a decisive contributing factor for the cutting tool performance
evaluated by the surface roughness of the workpieces finished by the cutting tool.

CLAIMS:
1. A method for treating a surface of a cutting tool, the method comprising:
blasting the surface of the cutting tool using a granular abrasive; and
brushing the blasted surface of the cutting tool.
2. The method of claim 1, wherein the cutting tool includes a coating layer coated onto a base
material.
3. The method of claim 1, wherein the abrasive is comprised of one or more elements selected
from a group consisting of mineral particles, ceramic particles, and metal particles.
4. The method of claim 1, wherein the size of the abrasive particles are 30 - 900 μm.
5. The method of claim 1, wherein the blasting is performed by injecting the abrasive onto the
surface of the cutting tool at a pressure of 1.0 - 2.5 bar.
6. The method of claim 1, wherein the blasting is performed by injecting a mixture of the
granular abrasive and water onto the surface of the cutting tool.
7. The method of claim 6, wherein the abrasive has a density of 0.8 -1.5 kg//.
8. The method of claim 1, wherein the brushing is performed for 50 - 200 seconds while either
one or both of a brush and the cutting tool is being rotated at a speed of 60-120 rpm.
9. The method of claim 8, wherein a lubricant is applied to the brush.

10. The method of claim 9, wherein the lubricant comprises solid particles having a size of 0.5-
10 p.
11. A cutting tool whose surface is treated by the method according to any one of claims 1
through 10.

The present invention relates to cutting tools and a method for treating a surface thereof.
The present invention provides a method for treating a surface of a cutting tool, the method
including blasting the surface of the cutting tool using a granular abrasive and brushing the
blasted surface of the cutting tool. The present invention also provides a cutting tool whose
surface is treated by the method. According to the present invention, the surface condition of the
cutting tool is improved, thereby achieving superior resistance to chipping while cutting a
workpiece and excellent durability by means of improvement in abrasion resistance and
toughness.