JPH0634892Y2 - End mill - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an end mill capable of preventing chattering of an end mill body.

[Prior Art] Generally, when performing cutting using an end mill,
Since each cutting edge is an intermittent cut that repeats cutting and non-cutting every one revolution of the end mill body, impact force is applied to the end mill body. Moreover, since the end mill has a cutting edge at the tip of the elongated columnar end mill body, the end mill body resonates due to the impact force during cutting, causing chattering.

For this reason, the cutting edge tip is likely to be damaged or the finished surface accuracy of the work material is likely to be deteriorated. Therefore, there has been a demand for an end mill that does not cause chattering in the end mill body.

Conventionally, as such an end mill, a so-called unequal division type end mill has been provided. In this end mill, a plurality of cutting blade tips are arranged such that the radial rake angle and the axial rake angle of their outer peripheral blades are constant, and they are arranged at the tip of the end mill body at different intervals in the circumferential direction. . In such an end mill, the cutting depth is different for each outer peripheral blade, so the cutting resistance is different, and therefore the magnitude of the impact force transmitted to the end mill body is different for each cutting edge tip, preventing resonance of the end mill body. It has the advantage of being idle to prevent chatter.

[Problems to be Solved by the Invention] However, in the above end mill, there is a problem that it is not possible to sufficiently meet the demand for preventing the end mill body from chattering and preventing the cutting edge tip from being damaged. It was That is, in the above end mill,
Since the radial rake angle and the axial rake angle of the outer peripheral edge of the cutting edge tip are all the same, the magnitude of the impact force received by the outer peripheral edge of each cutting edge tip varies slightly depending on the cutting depth, but the impact force The action direction of is the same for each outer peripheral blade. For this reason, an impact force directed in the same direction is always applied to the outer peripheral edge of each cutting edge tip, and this impact force is transmitted to the end mill body. Since the direction of the impact force transmitted to the end mill body is the same for each cutting edge tip, the end mill body easily resonates.

[Object of the Invention] The present invention has been made in view of the above circumstances, and it is possible to prevent resonance of the end mill body, and thus reliably prevent chattering of the end mill body, resulting in a cutting edge tip loss or the like. It is an object of the present invention to provide an end mill capable of preventing the above.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a throw-away tip of the same shape and size to each of a plurality of tip mounting seats provided on an end mill body that is rotated about an axis. The throw-away tip has a quadrangular plate shape, the lower surface of the quadrangular shape is brought into contact with the seat surface of the tip mounting seat, and the upper surface of the quadrangular shape is directed forward in the rotation direction of the end mill body. A cutting blade provided on the intersection line between the upper surface and one side surface is directed toward the outer peripheral side, and a cutting edge provided on the intersection line between the other side surface adjacent to the one side surface and the upper surface. In an end mill that is installed with the blade facing the tip side, the seat surface of the tip mounting seat that supports a part of the throw-away tip is different from that of the end mill in order to change the axial rake angle. In a side view in a plane including the axis line of the tool body, the tip surface of the tool body is inclined at a different angle from the seat surface of the tip mounting seat that supports the other throw-away tip, and is inclined away from the axis line from the tip end to the base end. In addition, in order to make the radial rake angle different, in the axial view from the tip side of the end mill main body, it is parallel to the straight line extending in the radial direction of the end mill main body, and the distance between this straight line is It is characterized in that it is different from the spacing on the seat surface of the mounting seat to be supported.

[Operation] In the end mill configured as described above, since the seat surface of the mounting seat to which one throw-away tip is mounted is inclined, the axial rake angle of the linear cutting edge changes in the axial direction of the tool body. Also, since the distance between the mounting seat of some throwaway tips and the straight line to the radius of the end mill body is different from other throwaway tips, the radial rake angle is different for each throwaway tip. Therefore, the impact directions applied to the end mill body are dispersed in various ways. In addition, the throw-away tips with straight cutting edges are attached at different angles, so the axial rake angle is relatively large for some cutting edges and relatively large for other cutting edges. Get smaller.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 5. FIG. 1 is a side view showing an end mill of an embodiment.

In FIG. 1, reference numeral 1 is an end mill body. The end mill main body 1 has a columnar shape, and two indexable inserts (cutting blades) A and B are attached to the tip thereof. As shown in FIG. 2, the throw-away tips A and B have the same shape and the same size and have a parallelogram shape in which the upper and lower surfaces are parallel to each other, and the upper surface 3 serving as a rake surface and the lower surface 3 serving as a seating surface. ′ Are all parallelogram shapes. Side surfaces 4 intersect with the long sides of the upper surface 3 and the lower surface 3 ′, and side surfaces 4 ′ intersect with the shorter side. The line of intersection between the upper surface 3 and the side surface 4 is the outer peripheral blade 5a, 5b.
And the line of intersection between the upper surface 3'and the side surface 4'is the tip blade.
It is used as 5c and 5d. The throw-away tips A and B are removably attached to the end mill body 1 by a clamp screw 6 with the lower surface 3'contacting the seat surface 1a at the tip of the tool body 1. By such attachment, the cutting edge of the throw-away tips A and B
5a and 5b are directed to the outer peripheral side, and the cutting edges 5c and 5d are directed to the tip side.

Here, the throw-away tip A separates its outer peripheral blade 5a from the plane S passing through the axis O of the end mill body 1 over the dimension indicated by X in FIG. The front end P ₁ and the rear end P ₂ of the outer peripheral blade 5a are arranged so as to be inclined from the axis O by the same dimension (see fourth), while being inclined in the positive direction at an angle indicated by α ₁ . With such an arrangement, the outer peripheral blade 5a of the throw-away tip A is provided with a positive radial rake angle indicated by an angle β ₁ formed by the radial line l ₁ and the plane S at the tip P ₁ thereof, as shown in FIG. positive axial rake angle indicated by θ ₁ to are assigned. Note that FIG. 5 is a view in which the throw-away tips A and B are unfolded along the rotational direction and sequentially expressed. Θ1 and θ2 in the figure correspond to α1 and α2 in FIG. 1, respectively, and The axis O corresponds to the axis S.

On the other hand, in the throw-away tip B, the outer peripheral blade 5b is separated from the plane S toward the rear in the rotational direction over the dimension indicated by Y (where Y> X) in FIG. 3, and the plane S in FIG. The front end P ₁ and the rear end P ₂ of the outer peripheral blade 5b are arranged so as to be inclined from the axis O by the same dimension and inclined in the positive direction at an angle indicated by α ₂ (here α ₂ <α ₁ ). There is. With such an arrangement, the outer peripheral blade 5b of the throw-away tip B has a radius line l ₂ and a plane S at the tip P ₁ thereof.
A radial rake angle indicated by an angle β ₂ formed by and is added, and a positive axial rake angle indicated by θ ₂ in FIG. 5 is added, and θ ₁ > θ ₂ . In addition, FIG.
FIG. 6 is a development view of an end mill for comparing and explaining the axial rake angles of 5a and 5b, and throw-away tips A and B rotate in the directions of arrows in the figure.

In such an end mill, one throw-away tip A is attached to the axial rake angle θ ₁ of the outer peripheral blade 5a.
Is arranged so as to be larger than the axial rake angle θ ₂ of the outer peripheral blade 5b of the other throw-away tip B, the direction of the impact force received by the outer peripheral blades 5a, 5b is the axial rake angle θ ₁ , θ _2. The direction of the impact force transmitted to the end mill body 1 depends on the throw-away tip A,
It depends on B. Therefore, the end mill body 1 does not resonate, and the occurrence of cracks can be reliably prevented. Further, in the above end mill, outer peripheral cutting edge 5a, 5b radial rake angle β1 of, beta ₂ also because they constitute different from each other, the direction of impact force transmitted to the end mill body 1 I above action coupled with becomes disordered, It is possible to more reliably prevent chattering. Therefore, not only the throw-away tip can be prevented from being damaged, but also the finishing surface accuracy can be greatly improved.

In the above embodiment, the axial rake angles θ ₁ and θ ₂ of the outer peripheral blades 5a and 5b are both set to a regular angle, but as shown in FIG. 6, which is developed and expressed similarly to FIG. Alternatively, the axial rake angle θ ₁ of _one outer peripheral blade 5a may be a positive angle, and the axial rake angle θ ₂ of the other outer peripheral blade b may be a negative angle. Further, as shown in FIG. 7, the axial rake angle θ
Both ₁ and θ ₂ may be negative angles. Also, the radial rake .beta.1, beta ₂ but is configured differently from each other, it may be the same.

[Effects of the Invention] As described above, the end mill of the present invention has the insert inserts of the same shape and the same size attached to each of a plurality of insert attachment seats provided on the end mill body that can be rotated about the axis. The throw-away tip is in the shape of a polygonal plate, and the lower surface of the square shape is brought into contact with the seating surface of the tip mounting seat, and the upper surface of the polygonal shape is attached so as to face forward in the rotation direction of the end mill body. The cutting edge provided on the intersection line between the upper surface and the one side surface toward the outer peripheral side, and the cutting edge provided on the intersection line between the upper surface and the other side surface adjacent to the one side surface. In the end mill that is mounted toward the tip side, the seat surface of the tip mounting seat that supports a part of the throw-away tip, the axial line of the end mill body in order to make the axial rake angle different. In a side view in a plane including, tilts away from the axis from the tip end to the base end of the tool body at a different angle from the seating surface of the tip mounting seat that supports the other throw-away tip, and , In order to make the radial rake angle different, in the axial view from the tip side of the end mill main body, it is parallel to the straight line extending in the radial direction of the end mill main body, and the distance between this straight line supports the other throw-away tip. Since it is characterized in that it is different from the spacing on the seat surface of the mounting seat, the following effects are achieved.

I. It is economical because a simple polygonal throw-away tip can be used and more than one corner can be used for cutting.

B. The throwaway tip of the insert seat of some throwaway tips is inclined with respect to the tool axis, and the distance from the tool radius is different from other throwaway tips in the axial view. The degree of change in the axial rake angle and radial rake is different for each. Therefore, the impact directions applied to the end mill body are dispersed in various ways, and the occurrence of cracks can be prevented.

C. Since the throw-away inserts with straight cutting edges are installed at different axial rake angles, the cutting edge with a relatively large axial rake angle achieves good sharpness and the axial rake angle is relatively large. When the cutting edge is set to be relatively small, the loci of the leading edge and the trailing edge of the cutting edge are similar to each other, so that good flatness of the work surface can be obtained.

[Brief description of drawings]

1 to 5 are views showing an embodiment of the present invention. FIG. 1 is a side view showing an end mill, FIG. 2 is a view taken in the direction of arrow II in FIG. 1, and FIG. 2 is a view in the direction of arrow III in FIG. 2, FIG. 4 is a bottom view for explaining the arrangement of the outer peripheral blade of the cutting blade tip, and FIG. 5 is a development view of the end mill in the rotational direction for explaining the axial rake angle of each outer peripheral blade. , FIG. 6 and FIG. 6 and FIG. 7 are views showing modified examples of the above embodiment, respectively, and are development views in the rotational direction of the end mill for explaining the axial rake angle. 1 ... End mill body, 3 ... top surface, 3 '... bottom surface, 4
・ 4 '... Side, 5a ... Outer peripheral blade (cutting edge), 5b ... Outer peripheral blade (cutting edge), 5c ... Tip blade (cutting edge), 5d ... Tip blade (cutting edge), O ... Axis, θ ₁ …… Axial rake angle, θ 2
...... Axial rake angle.

Claims (1)

[Scope of utility model registration request] 1. A throw-away tip of the same shape and size is attached to each of a plurality of tip mounting seats provided on an end mill body that is rotated about an axis, and the throw-away tip has a rectangular plate shape. None, contact the bottom surface of the square shape with the seat surface of the chip mounting seat,
Also, the rectangular upper surface is attached to the front in the rotation direction of the end mill main body, and the cutting edge provided at the line of intersection between the upper surface and one side surface is directed to the outer peripheral side and adjacent to the one side surface. In an end mill in which the cutting edge provided on the line of intersection between the other side surface and the top surface is attached toward the tip side, the seat surface of the tip mounting seat that supports a part of the throw-away tip has an axial rake angle. In a side view in a plane including the axis of the end mill main body, in order to make the difference different from the seat surface of the tip mounting seat that supports the other throw-away tip, the head is moved from the tip of the tool body toward the base end. In order to incline away from the axis and to make the radial rake angle different, in the axial view from the tip side of the end mill body, in the radial direction of the end mill body An end mill which is parallel to a straight line directed toward the end mill and has a distance between the straight line and the straight line which is different from the distance on the seat surface of a mounting seat which supports another throw-away tip.