JPH08318419A - End mill - Google Patents

Abstract

PURPOSE: To efficiently cool a cutting face of which temperature rises high at the time of cutting by providing an opening which supplies cutting oil on a bottom of a groove on the cutting face side of a blade at a tip of an end mill. CONSTITUTION: A blade 3 of an end mill is moved in the arrow B direction to cut an object to be cut 4. In particular, a cutting face 6 in the blade 3 is a part of which temperature becomes the highest due to friction between the object to be cut 4 and chips 9. A bottom of a groove on the cutting face 6 side is called end gash 7. An opening 2a of a cutting oil supply passage 2 is provided in the end gash 7. Cutting oil passes the supply passage 2 and is supplied to a cutting point (arrow A) from the opening 2a. Since cutting oil is directly jetted on the cutting face 6, it is possible to cool the cutting face 6 efficiently.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an end mill having a cutting oil supply hole at its tip.

[0002]

2. Description of the Related Art Cutting tools such as end mills and drills change their shapes due to damage to their cutting edges due to thermal / mechanical wear of the work and chips when cutting the work. . Such a change in the shape of the cutting edge affects the processing shape of the work piece, and the cutting itself may be impossible depending on the degree, so that the shape of the cutting edge is not changed is desired.

Therefore, when cutting, various cutting oils are supplied to the vicinity of the cutting edge of the cutting tool to reduce frictional resistance and cool the cutting portion to improve the tool life of the cutting tool. Further, the cutting oil has effects such as reducing the roughness of the finish processing surface and improving the chip discharge property due to its slipperiness.

As a method of supplying the cutting oil to the cutting portion,
There are a method of supplying from a cutting oil supply path provided in the cutting tool body (hereinafter referred to as a method) and a method of supplying from a nozzle or the like provided outside (hereinafter referred to as a method).

As an example of the above method, Japanese Patent Publication No. 5-32164
There is a twist drill as shown in. The twist drill has two spiral cutting oil supply passages inside the drill body, and opens in the flank of the cutting edge of the drill tip. In Japanese Utility Model Publication No. 4-53851, there is shown an end mill in which a supply path branched in the middle of the end mill body is provided, and the supply path is open to the flank of the cutting edge at the tip.

Since the drill of the cutting tools is an environment in which the cutting portion of the work is closed, the entire cutting portion becomes hot. When cooling in the case of drill cutting, the method of using an external nozzle cannot be applied because it is closed, but the cutting oil is supplied by the method of having a supply hole in the drill body to improve the effect.

On the other hand, in the case of the end mill, since the cutting portion is open, the entire cutting portion does not have a high temperature, but only the vicinity of the cutting point has a high temperature. Both methods and methods can be adopted in the end mill.

FIG. 5 is an enlarged cross-sectional view of the blade at the tip of the end mill adopting the method, and the blade 3 of the end mill is indicated by an arrow B.
The figure shows a state of moving in the direction, cutting the workpiece 4, and discharging the chips 9. FIG. 6 is a view of the bottom blade of this end mill as seen from the tip side. The first flank 5 is a portion near the cutting edge on the back side of the blade 3 in the rotation direction (the direction of arrow B), and the second flank 10 is the back portion following the flank.
An opening 12a of the supply path 12 is provided in the. Cutting oil is sprayed from the opening 12a through the supply path 12 (see arrow A in FIG. 5) and is supplied to the cutting point.

[0009]

Although the tool life is relatively extended by the supply of cutting oil by the above-mentioned method, the increase in the number of high-speed rotating machine tools makes it possible to increase the cutting speed and increase the cutting of hard materials such as hardened steel. Therefore, further extension of tool life is desired. Therefore, it is an object of the present invention to provide an end mill capable of further exhibiting the effect of cutting oil and further extending the tool life.

[0010]

The gist of the end mill according to the present invention is that an opening for supplying cutting oil is provided at the groove bottom of the blade at the tip end on the rake face side. Further, it is preferable that the opening is provided at a position deeper than the groove bottom forming the outer peripheral blade. Further, it is desirable that the lead of the cutting oil supply passage provided in the main body of the end mill is different from the lead of the outer peripheral blade of the end mill. Furthermore, it is preferable that the end mill is a ball end mill.

[0011]

When the action mechanism of the cutting oil is studied in detail, an opening for supplying the cutting oil is provided at the groove bottom on the rake face side of the blade at the tip end to directly rake the cutting oil as in the present invention. This time, we have found that the effect of cutting oil can be further enhanced by applying it to the surface.

When the temperature distribution of the cutting edge of the end mill is measured in detail, the part where the temperature becomes the highest by cutting is the rake face of the cutting edge. Therefore, by directly applying the cutting oil to the vicinity of the rake face, the rake face can be cooled more efficiently and damage to the blade can be reduced.

In supplying the cutting oil according to the above-mentioned conventional method, the supply hole is formed in the flank of the blade at the tip. Since the end mill cuts by rotation, no matter which part has an opening, it is applied to the entire cutting surface by the rotation of the blade, which helps reduce the frictional resistance of the cutting part. In this way, in the point that the cutting oil is applied to the cutting surface, the conventional method of supplying holes on the flank and the conventional method of the external nozzle are the same, and even when actually cutting, There was no difference in the effect expression of the cutting oil, and there was no advantage particularly by providing the supply passage in the end mill body.

However, as described above, by providing the supply hole in the groove on the rake face side, the cooling effect by the cutting oil can be more exerted than in the above conventional method, and
Since the cutting oil is supplied to the rotational movement direction side of the blade, the blade is immediately supplied to the cutting site corresponding to the work piece, and the lubricating effect can be further enhanced. In the case of a drill,
Since the cutting oil will fill the cut holes,
Even if the opening exists at any position, the whole is cooled and the effect is high.

Further, in the present invention, since the opening is provided at a position deeper than the groove bottom forming the outer peripheral blade, the direction of the opening can be arbitrarily set without being influenced by the twist angle of the outer peripheral blade. You can

That is, when the outer peripheral blade has an opening at a shallow position, the supply path from the rear end to the tip of the end mill body is provided along the twist of the outer peripheral blade. Then, the opening opened at the tip opens at the twist angle of the outer peripheral blade. For example, in a ball end mill, the tip of the blade draws a circular arc according to the helix angle of the outer peripheral blade, but in this case, the blade end opens perpendicularly to the blade surface (see (a) of FIG. 4), that is, the opening. Turns to the outside.

However, when the opening is provided at a deep position, it is not necessary to lay the supply passage along the outer peripheral blade, and the supply passage that passes at an arbitrary angle can be provided in the end mill main body. The direction of the opening can be set according to the angle, that is, the jetting direction of the cutting oil can be optimized (see (b) of FIG. 4). In the case of such a shallow position, it is also possible to direct the direction of the opening inward, that is, toward the rake face side, and by directing the opening inward, injection onto the rake face can be performed better and more efficiently. Can be cooled.

[0018]

FIG. 1 is an enlarged cross-sectional view of a blade at the tip of an end mill according to an embodiment of the present invention. As with FIG. 5, the blade 3 of the end mill moves in the direction of arrow B and the work 4 It shows the state of cutting. Of the blades 3, the rake face 6 is the part that reaches the highest temperature due to friction with the work piece 4 and the chips 9. The groove bottom on the rake face side is generally called a gash 7, and the gash 7 is provided with an opening 2a of the cutting oil supply passage 2. The same components as those in FIG. 5 are designated by the same reference numerals to avoid redundant description.

The cutting oil is supplied to the cutting point from the opening 2a through the supply passage 2 (arrow A). As described above, since the cutting oil is directly sprayed on the rake face 6, the rake face 6 can be efficiently cooled.

FIG. 2 is a view of the bottom blade of the ball end mill adopting the embodiment of FIG. 1 as seen from the tip side. The same components as those in FIG. 1 are designated by the same reference numerals to avoid redundant description. The end mill according to the present invention is not limited to the ball end mill, and may be a square end mill having a flat tip.

FIG. 3 is a side view of an end mill body 1 according to another embodiment of the present invention. On the outer wall of the end mill main body 1, the outer peripheral blade 14 is left toward the tip portion while leaving the handle 19 portion.
Are formed. The outer peripheral blade 14 is provided in a spiral shape with a helix angle r. Further, inside the end mill body 1, two spiral supply paths 2 are provided from the rear end toward the front end. The supply path 2 is at a position deeper than the groove bottom of the outer peripheral blade,
The outer peripheral blade 14 is formed of a lead different from the lead. The supply path 2 is not limited to the spiral shape as shown in FIG. 3, and may be straight. In addition, the supply and the helix angle of 2 are the outer peripheral blade 1
The direction different from 4 may be used.

Next, a cutting test conducted by using various end mills will be described. As Example No. 1, material: ultra-fine particle cemented carbide, diameter: 10 mm, shape of blade at tip: approximately 1/4 arc shape in side view of rotation locus, radius of blade at tip
Size: 5 mm, Number of blades: 2, Blade length: 18 mm, Total length: 1
00 mm, handle diameter: 10 mm, twist angle: 30 ° (peripheral blade lead: 54.4 mm), maximum peripheral groove depth: 1.5 mm,
Cutting oil supply channel numerical aperture: 2, supply channel diameter: 1.2 mm, supply channel position: 0.8 mm deeper than the deepest part of the groove of the outer peripheral blade, cutting oil supply channel lead: 54.4 mm. Then, a ball end mill was prepared in which the opening of the cutting oil supply path was provided in the gash of the blade at the tip. Further, as Example No. 2, a ball end mill similar to that of Example No. 1 above was prepared except that the lead of the cutting oil supply passage was 117.2 mm.

As Comparative Example No. 1, a ball end mill similar to that of Example No. 1 was prepared, in which the end mill main body does not have a cutting oil supply passage and the cutting oil is supplied from an external nozzle. did. Further, as Comparative Example No. 2, the opening of the cutting oil supply passage is provided in the second flank of the blade at the tip,
A ball end mill similar to that of Example No. 1 above was manufactured except for the above.

These Example Nos. 1 and 2 and Comparative Example No.
A cutting test was carried out on Nos. 1 and 2. The cutting conditions of the cutting test are as follows, and the results are shown in FIG. <Cutting conditions> Revolution: 6000 rpm Cutting speed: Maximum 113 m / mim. Feed rate: 1190 mm / min. (0.099 mm / blade) Depth of cut: 1 mm Pick feed: 0.2 mm Work material: SKD61 (JIS G 4404 ) Work material hardness: HRC52 Cutting oil: Water soluble Machine used: Vertical machining center

FIG. 7 is a graph showing the relationship between the cutting length (m) of the work piece and the flank wear width (μm) of the end mill.
As can be seen from FIG. 7, Comparative Example No. in which the opening is provided on the flank.
2 is a comparative example N of the method of supplying the cutting oil from the external nozzle.
Compared with o.1, it can be seen that there is little difference in wear width and there is no great difference in tool life. On the other hand, Example No. 1 is a comparative example N
Compared to o.1 and Comparative Example No. 2, the wear width is reduced by about 30% and the tool life is improved.

Further, the wear width of Example No. 2 is smaller than that of Example No. 1. This is because the lead of the supply path is different from the lead of the outer peripheral blade so that the ejection direction from the opening is directed closer to the cutting point. Example N
In the o.2 end mill, when re-grinding the tip blade, the position of the opening of the supply path shifts with respect to the tip blade. The effect of suppressing tool wear may be reduced. The above example N
o. In 1 and 2, the cutting oil supply passage has two openings, but it is not limited to this.

[0027]

Since the end mill according to the present invention is provided at the groove bottom on the rake face side of the blade at the tip, the effect of cutting oil can be further exerted, and the tool life can be further extended. Particularly, it is effective for shallow groove cutting, and is extremely effective for cutting where the end portion of the end mill is frequently used.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view showing a blade at a tip portion of an end mill according to an embodiment of the present invention.

2 is a view of the bottom blade of the ball end mill adopting the embodiment of FIG. 1 as seen from the tip side.

FIG. 3 is a side view showing an end mill according to another embodiment of the present invention.

FIG. 4 is a sectional view for explaining a direction of an opening of a supply path.

FIG. 5 is an enlarged cross-sectional view showing a blade at the tip of a conventional end mill.

FIG. 6 is a view of a bottom blade of a conventional ball end mill viewed from the tip side.

FIG. 7 is a graph showing the results of a cutting test.

[Explanation of symbols]

 2 Supply path 2a Opening 3 Blade 4 Workpiece 5 First flank 6 Rake face 7 Gash 9 Chips 10 Second flank 14 Outer peripheral blade

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasutaka Okazaki 179-1, Kanegasaki Nishioike, Uozumi-cho, Akashi-shi, Hyogo Kobe Steel Works Akashi Plant

Claims (4)

[Claims] 1. An end mill characterized in that an opening for supplying cutting oil is provided in a groove bottom on a rake face side of a blade at a tip portion of the end mill. 2. The end mill according to claim 1, wherein the opening is provided at a position deeper than a groove bottom forming the outer peripheral blade. 3. The end mill according to claim 2, wherein the lead of the cutting oil supply passage provided in the main body of the end mill is different from the lead of the outer peripheral blade of the end mill. 4. The end mill according to claim 1, wherein the end mill is a ball end mill.