KR100919002B1 - End mill - Google Patents

Abstract

This invention provides the end mill which can aim at prevention of environmental pollution.

The end mill 1 according to the present invention has an opening 5a which is opened along the spiral groove 4, and the opening 5a is the opening of the rear end face of the shank 2 through the intake passage 5. As a result of the configuration in communication with the air intake, the intake air is blown through the intake air passage 5 to forcibly attract the cutting chips generated during the cutting process to the opening portion 5a, and the sucked cutting chips are sucked into the rear end surface of the shank 2. It is possible to discharge to the outside from the opening of the. As a result, it is possible to suppress (or not require) the use of cutting fluid for discharging the cutting chips, as compared with the conventional one, and to prevent environmental pollution.

Description

End Mill {END MILL}

The present invention relates to an end mill, and more particularly, to an end mill capable of preventing environmental pollution.

In general, it is important to extend the life of the tool or to secure the machining accuracy by supplying cutting fluid during cutting process using the end mill.

As a method of supplying cutting fluid, an external supply method for supplying cutting fluid from the outside to the cutting edge side is common. In this method, the cutting fluid is scattered by centrifugal force during high-speed rotation, so that the supply of cutting fluid is not sufficiently supplied to the cutting edge. have. Accordingly, a technique related to the internal oil supply method for supplying cutting fluid through the oil supply hole penetrated into the end mill as a method excellent in effect compared to the conventional external oil supply method has been proposed (Patent Documents 1 to 4).

Patent Document 1: Japanese Patent Laid-Open No. 5-253727

Patent Document 2: Japanese Patent Laid-Open No. 6-31321

Patent Document 3: Japanese Patent Laid-Open No. 6-335815

Patent Document 4: Japanese Patent Application Laid-Open No. 2003-285220

In Figure 1 (a) is a front view of the end mill according to an embodiment of the present invention, (b) is a side view of the end mill seen in the direction of the arrow Ib of Figure 1 (a), (c) is Figure 1 (a) This is a partial enlargement of the end mill in which X is enlarged.

2 is a front view of the end mill supported by the holder.

In Fig. 3, (a) is an explanatory diagram for explaining a test method for cutting test, and (b) shows a test result for cutting test.

((Description of the sign))

End mill

2. Shank

3. Main body

3a. Outsourcing Day

3b. Lower blade

4. Spiral groove

5. With intake

5a. Opening

Lower groove diameter of Dg helix

Dh. Diameter to intake air

Dk. Diameter of outer edge

0. Axis

[Achievement to solve]

However, since cutting fluids generally contain harmful substances such as chlorine or phosphorus, there is a problem of causing environmental pollution when cutting fluids are used. As a result, it is necessary to recover the cutting fluid completely and the manufacturing cost is increased accordingly. Therefore, in recent years, development of a technology capable of suppressing the use of the cutting fluid has been desired.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an end mill capable of preventing environmental pollution by suppressing the use of cutting fluid.

[Solution Solution]

In order to solve the above object, the end mill of claim 1 is formed along a shank, a main body portion connected to the shank, a spiral groove recessed in a spiral shape around an axis of the main body portion, and a spiral groove formed therein. And a lower blade connected to the outer circumferential blade and formed on the outer circumferential blade, the lower blade being formed below the main body portion. And an intake path formed therein, the diameter of the intake path being smaller than the diameter of the blade of the outer circumferential edge and being larger than the lower diameter of the groove bottom of the spiral groove. And intake air through the intake air, and sucks the cutting chip generated at the time of cutting from the opening. It is comprised so that it may discharge | emit from the opening part of a shank rear end surface.

In the end mill of Claim 2, in the end mill of Claim 1, the diameter to the said intake air is set to the magnitude | size of 65% or less of the said outer blade diameter.

In the end mill of Claim 3, the end mill of Claim 2 is set to the magnitude | size of 110% or more and 135% or less of the groove lower diameter of the said spiral groove.

The end mill according to claim 4 is the end mill according to any one of claims 1 to 3, wherein the extended tip to the intake air becomes a position spaced apart from the lower portion of the main body, and the extended tip to the intake air The separation distance between the lower parts of the main body is set to a size of 50% or more and 85% or less of the outer blade diameter.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. First, an end mill 1 according to one embodiment of the present invention will be described with reference to FIG. In Figure 1 (a) is a front view of the end mill according to an embodiment of the present invention, (b) is a side view of the end mill seen in the direction of the arrow Ib of Figure 1 (a), (c) is Figure 1 (a) This is a partial enlargement of the end mill in which X is enlarged.

The end mill 1 is a tool for cutting a workpiece (not shown) by the rotational force transmitted from a processing machine (not shown), and press-sinters tungsten carbide (WC) or the like as shown in FIG. In addition to being composed of a solid type square end mill made of a cemented carbide, the main structure includes a shank 2 and a main body 3 connected to the shank 2. At this time, the end mill 1 is not limited to cemented carbide and may be composed of a high-speed coated oral.

The shank 2 is formed in a circumferential shape having an axis O as shown in FIG. 1 as a portion supported by the processing machine through the holder 10 (shown in FIG. 2). And the shank 2 is formed in the taper shape from which the outer diameter becomes small toward the front end side (right side of FIG. 1 (a)) of the shank 2, as shown in FIG.

The main body 3 is a part for performing cutting while rotating by the rotational force transmitted from the processing machine by using the shank 2, as shown in Figure 1 is less than the diameter of the shank (2) The outer peripheral edge 3a and the lower edge 3b are comprised as a main structure. Four spiral grooves 4 are each formed in a spiral shape on the outer circumference of the main body 3.

The outer circumferential edge 3a is a portion for cutting the workpiece, as shown in FIGS. 1A and 1C, along the spiral groove 4 described below by the four outer circumferential edges 3a. It is formed in the outer periphery of the main body 3. That is, in the present Example, the blade diameter Dk used as the diameter of the outer peripheral blade 3a is comprised by 3 mm.

Like the outer edge 3a, the lower blade 3b is a portion for cutting the workpiece, and as shown in FIG. 1, the four lower blades 3b are connected to the four outer edges 3a, respectively. And the lower part (the right part of Fig. 1 (a)) of the main body 3, respectively. In addition, the lower blade 3b is provided with the gash 3c (gashes), and each gash 3c constitutes the cutting surface of the lower blade 3b.

The spiral groove 4 constitutes a cutting surface of the outer circumferential edge 3a, and is a portion for accommodating the cutting chips generated in the outer circumferential edge 3a and the lower edge 3b during cutting. Similarly, it extends from the lower part of the main body 3 to the rear end of the main body 3 (the left side of FIG. 1 (a)). In this embodiment, the screw angle of the spiral groove 4 is comprised by 30 degrees.

The spiral groove 4 is formed by moving in the axial center O direction of the shank 2 from the lower part of the main body part 3 toward the rear end side of the main body part 3 in the state of rotating the disk-shaped abrasive stone. Accordingly, the spiral groove 4 is formed at the lower side (right side of FIG. 1 (a)) of the main body 3 with the lower groove formed substantially parallel to the shaft center O of the shank 2, and the main body ( At the rear end side of 3), the lower groove portion is cut and formed corresponding to the shape of the abrasive stone, and the lower groove diameter toward the rear end side of the main body portion 3 is formed to have a large diameter. On the other hand, in the present embodiment, the lower diameter Dg of the spiral groove 4 at the lower side of the main body portion 3 formed substantially parallel to the shaft center O of the shank 2 is composed of 1.5 mm.

1 (a) and 1 (c), inside the end mill 1, the shaft center O is formed from the rear end face of the shank 2 (left side of FIG. 1 (a)) to approximately the center. Therefore, the intake air passage 5 extends linearly. Specifically, the extension tip of the intake passage 5 is spaced apart from the lower part of the main body 3, and the separation distance between the extension tip and the lower part of the main body 3 is about 2 mm.

The air intake passage 5 is formed in a circular cross section by performing discharge machining on the shank 2 and the main body portion 3 as a site where air intake is performed during cutting, as described later, and having a diameter Dh of the outer edge 3a. It is formed with a diameter smaller than the blade diameter Dk of), and is formed larger than the groove lower diameter Dg of the spiral groove 4. On the other hand, in the present embodiment, the diameter Dh of the intake air passage 5 is composed of 2 mm.

Here, in the present embodiment, although the intake air passage 5 is formed by electric discharge machining, it may be formed by drilling. However, as in the end mill 1 according to the present embodiment, it is preferable to form the intake air 5 by discharge machining in an end mill having a small diameter composed of a blade diameter Dk of the outer circumferential edge 3a of about 3 mm. Do. That is, in the case of forming the intake airway 5 by drilling in an end mill of a small diameter, the thickness of the outer circumferential edge 3a becomes thin due to the vibration of the drill during the processing of the intake airway 5, resulting in a decrease in rigidity. In addition, the processing accuracy of the intake air passage 5 deteriorates and the shape of the opening portion 5a is not stabilized. The intake air passage 5 is formed by electric discharge machining to secure the rigidity of the outer edge. Can be formed into a stable shape. As a result, the tool life can be improved and the suction performance can be improved.

Since the diameter Dh of the intake passage 5 is smaller than the diameter Dk of the outer circumferential edge 3a and larger than the groove lower diameter Dg of the spiral groove 4, the intake passage 5 The opening 5a as in 1 (c) is formed.

The opening 5a is an intake air through the intake air 5 during cutting, and is a portion for sucking the cutting chips generated at the outer circumferential blade 3a and the lower blade 3b. As shown in Fig. 1 (c), the opening is formed along the spiral groove 4.

Next, a recovery method of the cutting chip using the end mill 1 configured as described above will be described with reference to FIG. 2 is a front view of the end mill 1 supported by the holder 10. In FIG. 2, a part of the end mill 1 is shown in cross section, and a part of the holder 10 is omitted. 2, the moving direction of the cutting chip is shown by the arrows A and B. In FIG.

2, the shank 2 is supported by the holder 10 and coupled to a processing machine (not shown), as shown in FIG. At the time of cutting, the intake of the internal space 11 formed inside the holder 10 from the processing machine side is achieved by using a pump (not shown). As a result, the end mill 1 is provided with intake air through the intake passage 5.

At this time, since the opening 5a is formed in the intake passage 5 as described above, the cutting is generated by the outer circumferential blade 3a and the lower blade 3b as indicated by the arrow A during cutting. It is possible to forcibly suck the chip from the opening portion 5a.

If the intake using the pump is made continuously, the cutting chips sucked from the opening 5a are drawn from the rear end surface of the shank 2 (upper side in Fig. 2) through the intake passage 5 as indicated by the arrow B. It is possible to discharge to the outside.

Next, the cutting test performed using the end mill 1 will be described with reference to FIG. Fig. 3 (a) is an explanatory diagram illustrating a test method of a cutting test, and Fig. 3 (b) shows a test result of a cutting test.

In the cutting test, as shown in Fig. 3 (a), the end mill 1 is perpendicularly opposed to the machining surface Cf of the workpiece C, and the end mill 1 is moved around the axis O. It is a test for investigating the dischargeability of the cutting chip produced at the time of cutting when moving in the direction intersecting the axis center O under the predetermined cutting conditions in the rotated state. In the cutting test, on the other hand, whether or not the discharge property is determined by the suction rate of the cutting chip (ratio of the generated cutting chip and the sucked cutting chip) is determined.

Detailed specifications of the cutting test are: workpiece: JIS-ADC12, machine used: vertical machining center, spindle speed: 12500rpm, table feedrate: 900mm / mim, depth of cut (a) [see Fig. 3 (a)]]: 3mm , Cutting amount b (see Fig. 3 (a)): 0.3 mm, working length c (see Fig. 3 (a)): 100 mm.

In addition, the cutting test is carried out by setting the diameter Dh of the end mill 1 (hereinafter referred to as "the present invention") and the intake air passage 5 described in this embodiment within a predetermined range (range of 1 mm to 2.2 mm). Various modified end mills were used.

According to the test result of the cutting test, it is understood that when the present invention is used as shown in Fig. 3 (b), the suction rate of the cutting chip is 100%, so that all the cutting chips generated at the time of cutting can be sucked. Therefore, the ejection property of the cutting chip was found to be good.

Similarly, even when the diameter Dh of the intake air passage 5 is set to 1.7 mm, it is understood that the suction rate of the cutting chip is 100%, so that all the cutting chips generated at the time of cutting can be sucked. Therefore, it was found that the dischargeability of the cutting chip was good.

In addition, when the diameter Dh of the intake hole 5 is set to 1 mm and 1.5 mm, it can be understood that the suction rate of the cutting chip is 0%, so that the cutting chip generated at the time of cutting cannot be sucked at all. Therefore, the chip chip discharge was found to be poor.

Since the diameter Dh of the intake hole 5 is smaller than or equal to the groove lower diameter Dg (= 1.5 mm) of the groove 4, the opening 5a is not formed in the intake hole 5 and is cut. It seems that the cause is that the chip cannot be sucked.

On the other hand, when the diameter Dh of the intake air passage 5 was 2.2 mm, the end mill broke. This is because the diameter Dh of the intake air passage 5 is large with respect to the blade diameter Dk (= 3 mm) of the outer circumferential edge 3a, which causes the thickness of the main body portion 3 to be thin and the tool strength decreases. It is considered to be present.

It is preferable to set the diameter Dh of the intake air passage 5 to 65% or less of the diameter Dk of the outer peripheral edge 3a through the above result. That is, when the diameter Dh of the intake passage 5 is larger than 65% of the blade diameter Dk of the outer circumferential blade 3a, the thickness of the main body portion 3 becomes thin, resulting in a decrease in rigidity. On the contrary, by setting the diameter Dh of the intake air passage 5 to 65% or less of the blade diameter Dk of the outer circumferential blade 3a, the thickness of the main body portion 3 can be ensured and its rigidity can be ensured. As a result, tool life can be improved.

The diameter Dh of the intake passage 5 is preferably set to a size of 110% or more and 135% or less of the groove lower diameter Dg of the spiral groove 4. That is, when the diameter Dh of the intake passage 5 is less than 110% of the groove lower diameter Dg of the spiral groove 4, the opening width of the opening 5a opened along the spiral groove 4 is Since it becomes narrower, it is difficult to sufficiently suck the cutting chips accommodated in the spiral groove 4 (for example, cutting chips at a position away from the opening 5a or relatively large cutting chips), resulting in a decrease in the suction performance. By setting the diameter Dh of the intake air passage 5 to the above size with respect to the groove lower diameter Dg of the spiral groove 4, the opening width of the opening portion 5a can be sufficiently secured. The cutting chips accommodated in the furnace spiral groove 4 can be sucked more reliably.

On the other hand, when the diameter Dh of the intake passage 5 exceeds 135% of the groove lower diameter Dg of the spiral groove 4, the opening width of the opening 5a opened along the spiral groove 4 is formed. Since the suction performance is increased, the suction performance is improved, but the rigidity of the main body 3 is reduced by the opening portion. The diameter Dh_ of the intake passage 5 is the lower groove diameter Dg of the spiral groove 4. By setting the size to the above size, it is possible to prevent the opening width of the opening portion 5a from being excessively wide and to secure the rigidity of the main body portion 3. As a result, the tool life can be extended in a state where the intake performance is secured.

As described above, according to the end mill 1 according to the present embodiment, the opening 5a is formed along the spiral groove 4, and the opening 5a passes through the intake passage 5. Since it consists of the structure which communicates with the opening of the rear end surface of the shank 2, it cuts intake through the air intake path 5, forcibly sucks the cutting chip produced | generated at the time of cutting from the opening part 5a, and sucks the cutting chip. Can be discharged from the opening of the rear end face of the shank 2 to the outside.

As a result, the use of cutting fluid for discharging the cutting chips can be suppressed (or not required) as compared with the conventional products, and the environmental pollution can be prevented. In addition, the use of cutting fluid can be suppressed (or not required), so that the cutting cost of cutting fluid can be reduced, so that the processing cost can be reduced.

Since the cutting chips sucked from the openings 5a can be discharged to the outside from the opening of the rear end of the shank 2 through the intake passage 5, the cutting chips are prevented from splashing onto the workpieces, thereby simplifying the cleaning operation. In addition, it is possible to reduce the processing accuracy due to the cutting chips spattered into the workpiece.

In addition, according to the end mill 1 according to the present embodiment, since the opening 5a is formed along the spiral groove 4 to suck the cutting chips from the opening 5a, the spiral groove 4 is as much as that. It is possible to set the storage capacity of the cutting chip by the low. That is, even if the volume of the spiral groove 4 (i.e., the width or depth of the spiral groove, etc.) is reduced, the entanglement of the cutting chips can be suppressed, so that the volume of the spiral groove 4 can be reduced. It is possible to increase the tool cross section as much as possible. As a result, the rigidity of the main body 3 can be secured and the tool life can be improved.

In addition, according to the end mill 1 according to the present embodiment, since one end of the intake passage 5 is opened to the rear end surface of the shank 2, cutting is performed compared to the case of opening to the side of the shank 2, for example. The structure of the holder 10 for discharging the chip can be simplified.

On the other hand, in the end mill 1 according to the present embodiment, the extension tip of the intake passage 5 is spaced apart from the lower part of the main body part 3 so that the separation distance between the extension tip and the lower part of the main body part 3 is approximately 2 mm. It has been described that the case consisting of (see Fig. 1 (a) and Fig. 1 (c)) the separation distance between the extension end and the lower part of the main body portion 3 is 50% of the blade diameter Dk of the outer edge (3a) It is desirable to set the size to 85% or more.

That is, when the separation distance is less than 50% of the blade diameter Dk of the outer edge 3a, the separation distance between the extension tip of the intake passage 5 and the lower portion of the main body portion 3 is excessively shortened. Due to the thinning of the thickness of the lower part of the main body 3, the rigidity of the main body 3 (lower part) is lowered, resulting in a decrease in tool life. The separation distance is defined by the blade diameter of the outer edge 3a. By setting the size with respect to Dk), the separation distance can be sufficiently secured to increase the thickness at the lower part of the main body 3, thereby securing the rigidity at the lower part and improving the tool life.

On the other hand, when the separation distance is greater than 85% of the blade diameter Dk of the outer edge 3a, the thickness of the lower portion can be thickened to ensure rigidity, but the end portion of the opening 5a is lowered from the lower edge 3b. Because of the separation, the cutting chips generated by the cutting action of the lower blade 3b (and the outer edge 3a near the lower blade 3b) cannot be sufficiently sucked, resulting in a decrease in the suction performance. By setting the distance to the size with respect to the blade diameter Dk of the outer circumferential blade 3a, it is possible to suppress the end of the opening 5a from being excessively far from the lower blade 3b. As a result, it is possible to improve suction performance while securing tool life.

As described above, the present invention has been described based on the embodiments, and the present invention is not limited to the above embodiments, but it can be easily estimated that various modifications and modifications can be made without departing from the spirit of the present invention.

For example, in the above embodiment, the case in which the end mill 1 is formed of a square end mill has been described. However, the present invention is not necessarily limited thereto, and may be a radial end mill or a ball end mill.

In addition, in the above embodiment, the four outer peripheral edges 3a are provided, and the four spiral grooves 4 forming the cutting surfaces of the four outer edges 3a are described. However, the present invention is not limited thereto, and for example, one, two or three spiral grooves 4 may be provided, or five or more spiral grooves 4 may be provided. On the other hand, when the one or two spiral grooves 4 are provided, the rigidity of the tool is lowered, so it is preferable that the spiral grooves of three or four spiral grooves are provided.

In the above embodiment, the outer edge 3a and the lower blade 3b have been described in the case where the main body 3 is formed. However, the present invention is not limited thereto, and the outer edge 3a and the lower blade 3b may be detachable. It is also possible to configure the end mill 1 as a detachable end mill by forming a (throw away chip) to be detachable to the main body portion 3. In this case, tool life can be improved by replacing chips.

In addition, in the above-described embodiment, the case where the extension front end of the intake passage 5 is configured to be spaced apart from the lower portion of the main body portion 3 is described, but is not necessarily limited thereto. It may be configured to extend through the lower portion to penetrate the intake passage 5. In this case, it is preferable to set the blade diameter Dk of the outer circumferential edge 3a to 5 mm or less in order to prevent a sufficient negative pressure from the opening portion 5a at the time of suction, so that the suction force is lowered. It is advantageous to set Dk) to 3 mm or less. More preferably, the blade diameter Dk is set to 2 mm or less.

According to the end mill according to claim 1, the opening is formed along the spiral groove, and the opening is in communication with the opening of the rear end face of the shank. There is an effect that it is possible to forcibly suck the cutting chip generated from the opening from the opening and discharge the sucked cutting chip from the opening of the shank rear end face to the outside.

As a result, since the use of cutting fluid for discharging the cutting chips can be suppressed (or not required), the environmental pollution can be prevented. In addition, since the use of the cutting liquid can be suppressed (or not required), the recovery cost of the cutting liquid can be reduced, and the machining cost can be reduced accordingly.

In addition, the cutting chips sucked from the openings can be discharged to the outside from the openings at the rear end of the shank through the intake air, so that the cutting chips can be prevented from splashing onto the workpieces, thereby simplifying the work to be cleaned. There is an effect that it is possible to prevent the processing precision from being lowered due to the chip cutting.

According to the present invention, since the opening is formed along the spiral groove to suck the cutting chip from the opening, the storage capacity of the cutting chip by the spiral groove can be set as low as that. That is, even if the volume of the spiral grooves (for example, the width and depth of the spiral grooves) is reduced, the entanglement of the cutting chips can be suppressed, so that the tool cross-sectional area can be increased by reducing the volume of the spiral grooves. Thereby, there is an effect that the rigidity of the main body can be secured and the tool life can be improved by that much.

In addition, according to the present invention, since one end of the intake air is opened to the rear surface of the shank, the structure of the holder for discharging the cutting chip can be simplified as compared with the case of opening to the shank side.

According to the end mill of Claim 2, in addition to the effect exhibited by the end mill of Claim 1, since the diameter to the intake air is set to the size of 65% or less of the outer blade diameter, it is possible to ensure the rigidity of the main body part. It is effective.

That is, when the diameter of the intake air is larger than 65% of the outer diameter of the outer blade, the thickness of the main body becomes thin, resulting in a decrease in rigidity. On the other hand, according to the present invention, since the diameter of the intake air is set to 65% or less of the outer blade diameter, it is possible to secure the thickness of the main body and to ensure sufficient rigidity, thereby improving tool life.

According to the end mill of claim 3, in addition to the effects of the end mill of claim 2, the diameter of the intake air is set to a size of 110% or more and 135% or less of the groove lower diameter of the spiral groove, thereby ensuring intake performance and tool life. It is effective that the improvement can be simultaneously planned.

That is, when the diameter of the intake path is less than 110% of the lower diameter of the groove of the spiral groove, the opening width of the opening formed along the spiral groove is narrowed so that the cutting chip accommodated in the spiral groove (for example, It is difficult to sufficiently suck the cutting chip in a distant position or a relatively large cutting chip), resulting in a decrease in suction performance, but according to the present invention, the diameter of the intake path is set to the size with respect to the lower diameter of the spiral groove groove. Therefore, the opening width of the opening can be sufficiently secured, so that the cutting chips accommodated in the spiral groove can be sucked more reliably.

On the other hand, when the diameter of the intake path is larger than 135% of the lower diameter of the groove of the spiral groove, the opening width of the opening formed along the spiral groove becomes wider, so that the suction performance is improved, but the rigidity decrease of the body portion by the opening width. In consequence, according to the present invention, since the diameter of the intake path is set to the size with respect to the lower diameter of the spiral groove groove, the opening width of the opening can be suppressed from being excessively wide to secure the rigidity of the main body. As a result, the tool life can be improved while the suction performance is secured.

According to the end mill of Claim 4, in addition to the effect by the end mill of any one of Claims 1-3, the front end to an intake path is arrange | positioned at the position spaced apart from the lower part of a main body part, and Since the distance between the lower part and the lower part is set to a size of 50% or more and 85% or less of the blade diameter of the outer edge, it is effective to secure suction performance and improve tool life.

That is, when the separation distance is less than 50% of the blade diameter of the outer edge, the separation distance between the tip of the intake air and the lower part of the main body becomes excessively short, and the thickness of the lower part of the main body becomes thinner, thereby causing the main body part ( The rigidity of the lower part) is lowered, resulting in a decrease in tool life. According to the present invention, the separation distance can be set to the size with respect to the blade diameter of the outer edge so that the rigidity in the lower part can be secured. It is possible to improve the life.

On the other hand, when the separation distance is larger than 85% of the outer edge of the blade, the thickness of the lower part can be thickened to ensure rigidity, but the end of the opening portion is separated from the lower part so that the lower part (and the outer edge of the lower part) is removed. The cutting chip generated by the cutting action cannot be sufficiently sucked, resulting in a decrease in the suction performance. According to the present invention, the end of the opening portion is formed because the separation distance is set to the size with respect to the blade diameter of the outer edge. Away from the bottom can be suppressed. As a result, the suction performance can be improved while the tool life is secured.

Claims (4)

A shank, a main body portion extending from the shank, a spiral groove recessed in a spiral shape around the center of the main body portion, an outer edge formed along the spiral groove, and an outer edge formed from the outer edge to form a lower portion of the main body portion. In the end mill provided with a lower blade, An intake path extending in a straight line along the axis from the rear end surface of the shank to the main body portion and formed in a circular cross section; The diameter of the intake passage is smaller than the diameter of the blade of the outer circumference and is larger than the lower diameter of the groove bottom of the spiral groove, and the intake passage has an opening formed along the spiral groove, The end mill is configured to suck the cutting chips generated during the cutting process by the intake air through the intake air from the openings and to discharge them from the openings of the shank rear end face. The end mill according to claim 1, wherein the diameter of the intake passage is set to a size of 65% or less of the outer blade diameter. 3. The end mill according to claim 2, wherein the diameter of the intake passage is set to a size of 110% or more and 135% or less of the groove lower diameter of the spiral groove. The extension tip to the intake air is at a position spaced apart from a lower portion of the main body portion, An end mill, wherein the separation distance between the extension leading to the intake air and the lower part of the main body is set to a size of 50% or more and 85% or less of the outer blade diameter.