JPH0790411B2 - Throw-away type rolling tool - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a throwaway type rolling tool in which a plurality of throwaway chips are mounted along a plurality of grooves formed on the outer periphery of a tool body. It is a thing.

[Prior Art] FIGS. 4 to 6 show a throwaway type end mill (hereinafter abbreviated as an end mill) which is an example of a conventional throwaway rolling tool (hereinafter abbreviated as a cutting tool) of this type. .), And reference numeral 1 in the drawing denotes an end mill body (tool body).

The end mill body 1 is of a substantially cylindrical shape, and has four grooves 2 having a twist along the axial direction on the outer periphery of the tip end portion thereof.
Are formed at equal intervals in the circumferential direction. Here, the twist angles of these groove portions 2 ...
It is said that. Further, a plurality of (2 to 3 in the figure) rectangular groove-like chip mounting seats 4 are provided on the wall surface 3 of each groove portion 2 facing the rotation direction from the tip end portion to the base end portion of the end mill body 1. It is formed at a predetermined interval. Throw-away chips (hereinafter, simply referred to as "chips") 5 ... Are removably attached to the chip mounting seats 4 ... With clamp screws 6.

These chips 5 are made of cemented carbide or the like and have a rectangular plate shape whose upper and lower surfaces are parallel to each other.
Are positioned on the outer peripheral side of the end mill main body 1 as outer peripheral cutting blades, and are continuously mounted in the axis O direction of the end mill main body 1 in the rotation locus. Further, the cutting blade 7a on the tip side of the chips 5, 5 mounted on the tip portion of the end mill body 1 is a bottom blade. Here, the bottom surface of the chip mounting seat 4 is formed parallel to the wall surface 3 of the groove portion 2.
Therefore, as shown in FIG. 6, these chips 5 are mounted with an axial rake angle θ which is equal to the twist angle θ of the groove portions 2.

[Problems to be Solved by the Invention] However, in the above-described conventional end mill, a relatively small vibration is generated under constant cutting conditions such as the number of revolutions and the feed rate, and the small vibration causes the chips 5 ... The cutting edge 7 may be damaged, or especially the end mill body 1
When the bottom surface of the work piece is cut by the bottom blade, the finished surface may deteriorate, and when high surface roughness is required, heavy cutting (deep cutting), or high feed. It was difficult to say that it was sufficiently satisfactory when cutting with.

[Pursuit of Cause of Problem] Then, as a result of pursuing the cause of relatively small vibration in the rolling tool of this type, the inventor of this application obtains the presumption that the cause is as follows. Came to.

That is, in the above-mentioned conventional end mill, since the axial rake angles θ of the respective chips 5 are equal to each other and the respective groove portions 2 are formed at equal intervals in the circumferential direction, as shown in FIG. The circumferential intervals from the cutting edge 7 which is the outer peripheral cutting edge of the chip 5 mounted on the chip to the cutting edge 7 of the chip 5 mounted on the adjacent groove 2 are constant. There is. In addition, since the axial rake angle θ of each chip 5 is equal to each other, the cutting resistance generated by each chip 5 and the time during which each chip 5 participates in cutting are uniform.

Therefore, when a cutting load is applied to these chips 5, the end mill body 1 is intermittently subjected to a cutting resistance of a constant interval and a constant magnitude. That is, since the end mill main body 1 is given a constant vibration by the chips 5 ... When the frequency reaches 2 ⁿ , which is the natural frequency of the end mill main body 1, it resonates with it, resulting in a small but rough surface. We have come to the presumption that vibration is generated to the extent that it adversely affects the frequency.

[Object of the Invention] The present invention has been made based on the above estimation, and it is possible to prevent relatively small vibrations from occurring in the tool body, thereby improving the finished surface and performing heavy cutting (deep cutting). It is an object of the present invention to provide a rolling tool that enables high-feed cutting.

[Means for Solving the Problems] In the present invention, the axial rake angle of each throw-away tip mounted in a plurality of groove portions provided on the tool body is arranged adjacent to the groove portion of the same. Has proposed a throw-away type milling tool that is set to incline at different angles in the same inclination direction with respect to the axial rake angle of the indexable insert.

[Operation] Chips having different rake angles mounted along the same groove have different magnitudes of cutting resistance and different times involved in cutting. Therefore, the magnitude of the cutting force acting on the main body of the end mill by these chips and the acting time thereof vary irregularly in the axial direction of the end mill. As a result, regular vibration that resonates in the end mill body does not occur,
It is possible to prevent the occurrence of vibration that deteriorates the finished surface of the end mill body.

Furthermore, since the axial rake angles of all throw-away inserts arranged in the groove of the same line are set in the same inclination direction, the axial load that the end mill body receives from the workpiece during cutting is always in the same direction. To be taken. This makes it possible to suppress vibration of the end mill body in the axial direction due to the progress of cutting.

[Embodiment] FIGS. 1 to 3 show an end mill which is an embodiment of the rolling tool of the present invention, and the same reference numerals are given to the same parts as those shown in FIGS. 4 to 6. Is attached and its description is omitted.

1 to 3, in this end mill,
Chip mounting seats 11, 1 are installed in the groove portions 2 for mounting the three chips 5 in order from the front end side to the base end side of the end mill body 1.
Grooves 2 and 13 for mounting the two chips 5 and 5 ...
Chip mounting seats 14 and 15 are respectively formed on the.

Then, as shown in FIG.
The bottom surface of the chip mounting seat 11 on which the chip 5, which is the bottom blade, is mounted at the most distal end of the end mill main body 1 out of 15,
The inclination angle α is smaller than the twist angle θ of the groove 2 with respect to the axis. Further, the inclination angles of the bottom surfaces of the chip mounting seats 12 and 14 located on the base end side of the chip mounting seat 11 are substantially the same angle α ₁ as the twist angle θ. further,
The inclination angles of the bottom surfaces of the chip mounting seats 13 and 15 located on the base end side of the chip mounting seats 12 and 14 are set to an angle α ₂ larger than the twist angle θ.

Then, the chips 5 ... Are removably mounted on the chip mounting seats 11 to 15, respectively. As a result, the axial rake angle of the chip 5 mounted on the chip mounting seat 11 is set to α, and the axial rake angle of the chips 5 mounted on the chip mounting seats 12 and 14 as outer peripheral cutting edges is α. _1, and the axial rake angle of the tip 5, which is attached to the tip mounting seats 13 and 15 and serves as the outer peripheral cutting edge, is α ₂
It is said that.

In the end mill having the above structure, the axial rake angle of the chips 5 along each groove 2 is set to be gradually increased from the tip end side of the end mill body 1 toward the base end side. The circumferential length of the cutting blades 7, ..., In other words, the time involved in the cutting of the cutting blades 7 gradually increases toward the base end side of the end mill body 1. Further, the cutting resistance of these chips 5 becomes gradually smaller toward the base end side of the end mill body 1.

Therefore, the magnitude of the cutting resistance acting on the end mill body 1 by these chips 5 ...
Since it changes irregularly in the axial direction of the end mill,
No regular vibration is applied to the end mill body 11.
For this reason, it is possible to prevent co-vibration that causes the cutting edge 7 of the end mill body 11 from being damaged or deteriorates the finished surface roughness of the bottom surface of the workpiece.

Moreover, since the cutting resistance of the chips 5 on the base end side of the end mill main body 1 is reduced, the power required for cutting can be reduced, and in this sense, vibration and chatter of the end mill main body 1 are further reduced. It can be effectively suppressed.

In addition, in the end mill of the above embodiment, four groove portions 2 ... Are formed in the end mill main body 1, but the number of groove portions is not limited to four as long as it is plural.

Further, although the twist angles θ of the four groove portions 2 are set to be the same, the present invention is not limited to this, and one or more of the groove portions 2 may have different twist angles. Good. In this case, since the intervals in the circumferential direction of the chips are also irregular, a further excellent vibration damping effect can be obtained by the so-called unequal twist effect.

In addition, the sizes of the above-mentioned axial rake angles α, α ₁ and α ₂ are not limited to this, and various combinations of angles can be used. Furthermore, these axial rake angles α, α ₁ and α ₂ can be combined. The magnitudes of all may be set to negative angles.

Further, the present invention is not limited to only the end mill,
It can also be applied to other milling tools such as flat milling cutters and side milling cutters.

[Advantages of the Invention] As described above, according to the rolling tool of the present invention, the axial rake angle of each throw-away tip mounted along the groove of the tool body is arranged adjacent to the groove of the same line. Since it is set to have different angles in the same inclination direction with respect to the axial rake angle of other throw-away inserts, the cutting resistance and cutting time due to the chips acting on the tool body will change in the axial direction. As a result, the frequency of the vibration generated in the tool body becomes irregular, resulting in co-vibration that causes the cutting edge of the chip to break in the tool body or deteriorates the finished surface of the bottom surface of the workpiece. Can be prevented, especially heavy cutting (deep cutting)
In the above, remarkable effects can be obtained from low feed to high feed, and required power can be reduced.

Further, according to the throw-away type rolling tool of the present invention, the axial rake angles of all the throw-away tips arranged in the groove portion of the same line are provided in the same inclination direction at different angles, so that they can be rolled at the time of cutting. Since the axial load applied to the cutting tool is always in the same direction, it is possible to reduce vibration in the axial direction.

[Brief description of drawings]

1 to 3 show one embodiment of the rolling tool of the present invention. FIG. 1 is a side view, FIG. 2 is a front view, FIG. 3 is a side development view, and FIGS. FIG. 6 shows a conventional rolling tool, FIG. 4 is a side view, FIG. 5 is a front view, and FIG. 6 is a side development view. 1 ... End mill body, 2 ... groove part, 5 ... throwaway chip (chip), 11,12,13,14,15 ... Chip mounting seat, θ ... Twist angle, α, α ₁ , α ₂ ... … Axial rake.

Claims (1)

[Claims] 1. A plurality of groove portions extending in the axial direction are formed on the outer periphery of a tool body, and a plurality of throw-away tips having cutting blades along the groove portions are mounted as outer peripheral cutting blades or bottom blades, respectively. In the throw-away type turning tool, the axial rake angle of each throw-away tip is tilted in the same tilt direction and at a different angle with respect to the axial rake angle of the other throw-away tips adjacent to the groove of the same line. A throw-away type milling tool characterized by being set to