End mill manufacturing method

Abstract

In an end mill in which three or more odd-numbered gashs are provided at the tip of the tool body to form three or more odd-numbered bottom cutting edges, when the tool body is rotated at high speed to perform cutting, chatter vibration is prevented from occurring in the tool body, thereby improving the finish of the machined surface of the workpiece and enhancing chip evacuation. [Solution] In an end mill in which three gashes 11a to 11c are provided at the tip of the tool body 10 to form three bottom cutting edges 13a to 13c, with one bottom cutting edge 13a formed to reach the rotation center o, while the other bottom cutting edges 13b and 13c are formed not to reach the rotation center, the size of the gashe provided in relation to each bottom cutting edge is adjusted to bring the center of gravity of the tool body closer to the rotation axis L.

Description

Technical Field

[0001] The present invention relates to an end mill in which a plurality of gullets are provided at the tip of a tool body to form a plurality of bottom edges. In particular, three or more odd-numbered gullets are provided at the tip of the tool body to form three or more odd-numbered bottom edges. While one of the odd-numbered bottom edges is formed to reach the rotation center, the other bottom edges are formed so as not to reach the rotation center. When the tool body is rotated at high speed for cutting, chatter vibration occurs in the tool body, which deteriorates the finish of the machined surface of the workpiece. At the same time, it is characterized in that the chip discharge property is improved.

Background Art

[0002] Conventionally, an end mill in which a plurality of gullets are provided at the tip of a tool body to form a plurality of bottom edges has been used for rotating and cutting a workpiece.

[0003] As such an end mill, in Patent Documents 1 and 2, three gullets are provided at the tip of the tool body to form three bottom edges. While one of the bottom edges is formed to reach the rotation center, the other two bottom edges are formed so as not to reach the rotation center.

[0004] Here, as shown in Patent Documents 1 and 2, when three gullets are provided at the tip of the tool body to form three bottom edges, and one of the bottom edges is formed to reach the rotation center while the other two bottom edges are formed so as not to reach the rotation center, the volume of the gullet forming the bottom edge on the rear side in the rotation direction of the bottom edge formed to reach the rotation center becomes small, causing an offset in the center of gravity of the tool body. When the tool body is rotated at high speed for cutting, chatter vibration occurs in the tool body, deteriorating the finish of the machined surface of the workpiece. At the same time, the chip discharge property of the chips cut by the bottom edge on the rear side in the rotation direction of the bottom edge formed to reach the rotation center deteriorates, resulting in problems such as chip jamming.

Prior Art Documents

[0005] [Patent Document 1] Patent No. 6246825 [Patent Document 2] Patent No. 6709788 [Disclosure of the Invention] [Problems that the invention aims to solve]

[0006] The present invention aims to solve the aforementioned problems in an end mill in which three or more odd-numbered gashs are provided at the tip of the tool body to form three or more odd-numbered bottom cutting edges, one of the odd-numbered bottom cutting edges is formed to reach the center of rotation, while the other bottom cutting edges are formed not to reach the center of rotation.

[0007] In other words, the present invention is characterized in that, in an end mill in which three or more odd-numbered gashs are provided at the tip of the tool body to form three or more odd-numbered bottom cutting edges, one of the three or more odd-numbered bottom cutting edges is formed to reach the center of rotation, while the other bottom cutting edges are formed not to reach the center of rotation, the present invention prevents the center of gravity of the tool body from shifting, suppresses chatter vibration in the tool body when the tool body is rotated at high speed for cutting, improves the finish of the machined surface of the workpiece, and improves the discharge of chips cut by the bottom cutting edge on the rear side in the direction of rotation of the bottom cutting edge formed to reach the center of rotation, thereby preventing chip clogging. [Means for solving the problem]

[0008] In the end mill according to the present invention, in order to solve the above-mentioned problems, three or more odd-numbered gashs are provided at the tip of the tool body to form three or more odd-numbered bottom cutting edges, and one of the odd-numbered bottom cutting edges is formed to reach the center of rotation, while the other bottom cutting edges are formed not to reach the center of rotation. In this end mill, the size of the gash provided in accordance with each of the bottom cutting edges is adjusted to bring the center of gravity of the tool body closer to the axis of rotation.

[0009] In an end mill in which three or more odd-numbered gashs are provided at the tip of the tool body to form three or more odd-numbered bottom cutting edges, and one of the odd-numbered bottom cutting edges is formed to reach the center of rotation, while the other bottom cutting edges are formed not to reach the center of rotation, by adjusting the size of the gash provided in accordance with each of the bottom cutting edges, the center of gravity of the tool body is brought closer to the axis of rotation, thereby suppressing chatter vibration in the tool body when cutting by rotating the tool body at high speed, and improving the finish of the machined surface of the workpiece.

[0010] Here, in adjusting the size of the gashs provided for each bottom cutting edge so that the center of gravity of the tool body is brought closer to the axis of rotation as described above, the inclination angle in the depth direction and / or the opening angle in the radial direction of the gashs provided for each bottom cutting edge can be adjusted. In this way, variations in the size and volume of the gashs provided for each bottom cutting edge can be suppressed, the chip discharge performance in the gash can be made consistent, and chip clogging can be prevented.

[0011] Furthermore, when adjusting the inclination angle in the depth direction and / or the opening angle in the radial direction of the gash provided for each bottom blade as described above, in order to bring the center of gravity of the tool body closer to the axis of rotation, the thickness of the tool body is large on the rear side in the rotational direction of the bottom blade formed to reach the center of rotation, and the volume of the chip discharge section is small. Therefore, it is preferable to increase the inclination angle in the depth direction and / or the opening angle in the radial direction of the gash that forms the bottom blade at the rear side in the rotational direction of the bottom blade formed to reach the center of rotation, thereby increasing the size of the gash that forms the bottom blade at the rear side in the rotational direction of the bottom blade formed to reach the center of rotation, and suppressing variations in the size and volume of the gash provided for each bottom blade. [Effects of the Invention]

[0012] In the present invention, an end mill is provided with three or more odd-numbered gashs at the tip of the tool body to form three or more odd-numbered bottom cutting edges, with one of the odd-numbered bottom cutting edges being formed to reach the rotation center, while the other bottom cutting edges are formed not to reach the rotation center. By adjusting the size of the gashs provided in accordance with each bottom cutting edge as described above, the center of gravity of the tool body is brought closer to the rotation axis. As a result, when the tool body is rotated at high speed for cutting, chatter vibrations in the tool body are suppressed, and the finish of the machined surface of the workpiece is improved.

[0013] Furthermore, in adjusting the size of the gashs provided for each bottom cutting edge so that the center of gravity of the tool body is closer to the axis of rotation, the angle of inclination in the depth direction and / or the opening angle of the gashs provided for each bottom cutting edge are adjusted. In particular, by increasing the angle of inclination in the depth direction and / or the opening angle of the gashs forming the bottom cutting edge behind the bottom cutting edge in the rotation direction, variations in the size and volume of the gashs provided for each bottom cutting edge are suppressed, the chip discharge performance in each gash is made more consistent, and chip clogging can be prevented. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic front view of the tip side of an end mill according to an embodiment of the present invention, showing a state in which three gases are provided at the tip of the tool body to form three bottom cutting edges. [Figure 2] This is a schematic side view of an end mill according to the same embodiment. [Figure 3] In the end mill according to the same embodiment, (A) is a schematic front view of the tip side showing the first bottom cutting edge formed by the first gash provided to reach the rotation center of the tool body with the bottom cutting edge facing downwards, and (B) is a side explanatory view showing the inclination angle in the depth direction (gash angle) of the first gash. [Figure 4] In the end mill according to the same embodiment, (A) is a schematic front view of the tip side showing the state in which the second bottom cutting edge, formed in front of the first bottom cutting edge in the rotational direction, is facing downwards so as not to reach the rotational center of the tool body, and (B) is a side explanatory view showing the inclination angle in the depth direction (gash angle) of the second gash, which is machined to provide the second bottom cutting edge. [Figure 5] In the end mill according to the same embodiment, (A) is a schematic front view of the tip side showing the third bottom cutting edge, which is formed behind the first bottom cutting edge in the rotational direction, facing downwards so as not to reach the rotational center of the tool body, and (B) is a side explanatory view showing the inclination angle in the depth direction (gash angle) of the third gash, which is machined to provide the third bottom cutting edge. [Figure 6] This is an enlarged front view of the tip side of the end mill according to the same embodiment, showing the radial opening angle (gash opening angle) of the first to third gashes provided at the tip of the tool body. [Best Mode for Carrying Out the Invention]

[0015] The end mill in one embodiment of the present invention will be described in detail below with reference to the attached drawings. Note that the end mill in the present invention is not limited to those shown in the embodiments below, and can be modified as appropriate without altering its essence.

[0016] In the end mill of this embodiment, as shown in Figures 1 to 6, a first gash 11a, a second gash 11b, and a third gash 11c are provided on the outer circumference of the tip of the tool body 10 as gashes, in succession towards the front of the tool body 10 in the direction of rotation, so as to be continuous with the corresponding helical grooves 12a, 12b, and 12c, respectively.

[0017] Furthermore, the first gash 11a provides a first bottom blade 13a so as to reach the rotation center o of the tool body 10, the second gash 11b provides a second bottom blade 13b so as not to reach the rotation center o of the tool body 10, and the second gash 11b provides a second bottom blade 13b so as not to reach the rotation center o of the tool body 10, and the third gash 11c provides a third bottom blade 13c so as not to reach the rotation center o of the tool body 10, and the third gash 11c provides a third gash 11b provides a third bottom blade 13c so as not to reach the rotation center o of the tool body 10, and the third gash 11c provides a third gash 11b provides a third gash 11c so as not to reach the rotation center o of the tool body 10.

[0018] Here, when providing the first gash 11a, the second gash 11b, and the third gash 11c, as shown in Figures 3(A), (B) to 5(A), (B), when comparing the depth-direction inclination angles (hereinafter referred to as gash angles) δa, δb, and δc of the first to third gashs 11a, 11b, and 11c with respect to the tip surface perpendicular to the rotation axis L of the tool body 10, the gash angle δc of the third gash 11c located behind the first bottom cutting edge 13a in the rotation direction, which reaches the rotation center o of the tool body 10, is greater than the gash angle δa of the first gash 11a. The gash angle δb of the second gash 11b is made to be larger than that of the first gash 11a and the second gash 11b. Furthermore, as shown in Figure 6, when comparing the radial opening angles (hereinafter referred to as gash opening angles) γa, γb, and γc of the tool body 10 in the first to third gashes 11a, 11b, and 11c, the gash opening angle γc of the third gash 11c, located behind the first bottom cutting edge 13a in the rotational direction leading to the rotation center o of the tool body 10, is made to be larger than the gash opening angle γa of the first gash 11a and the gash opening angle γb of ​​the second gash 11b.

[0019] Then, if the clearance angle δc and the clearance opening angle γc of the third clearance 11c behind the first bottom edge 13a reaching the rotation center o of the tool body 10 in the rotational direction are made larger than the clearance angle δa and the clearance opening angle γa of the first clearance 11a and the clearance angle δb and the clearance opening angle γb of the second clearance 11b, the portion of the tool body 10 where the thickness on the rear side in the rotational direction of the formed first bottom edge 13a reaching the rotation center o becomes larger is cut more by the third clearance 11c, the variations in the size and volume of the first to third clearances 11a, 11b, 11c are suppressed, the center of gravity of the tool body 10 approaches the rotation axis L, and when the tool body 10 is rotated at high speed for cutting, the occurrence of chatter vibration in the tool body 10 is suppressed, and the finish of the machined surface of the workpiece is improved.

[0020] Also, as a result of suppressing the variations in the size and volume of the first to third clearances 11a, 11b, 11c, the chip discharge performance in the first to third clearances 11a, 11b, 11c is made constant, and the chips cut by the first to third bottom edges 13a, 13b, 13c are appropriately guided through the corresponding first to third clearances 11a, 11b, 11c to the respective twist grooves 12a, 12b, 12c and discharged, preventing the chips from being clogged.

[0021] In this embodiment, an end mill provided with three clearances 11a, 11b, 11c and three bottom edges 13a, 13b, 13c is shown, but it is also possible to provide five clearances and five bottom edges.

[0022] Furthermore, although this embodiment shows an end mill with a constant helix angle and distribution of bottom cutting edges, in the case of an end mill with an unequal lead that varies the helix angle, or an end mill with an unequal division that has an unequal distribution of bottom cutting edges, the size of the gash provided in relation to each bottom cutting edge can be adjusted, similar to the embodiment described above, to suppress variations in the size and volume of each gash and bring the center of gravity of the tool body closer to the axis of rotation. [Explanation of Symbols]

[0023] 10: Tool body 11a: The first gash 11b: The second gash 11c: Third Gash 12a, 12b, 12c: Helical groove 13a: First bottom blade 13b: Second bottom blade 13c: Third bottom edge L:Rotation axis center o: Center of rotation γa: Gash opening angle of the first gash γb: Gash opening angle of the second gash γc: Gash opening angle of the third gash δa: Gash angle of the first gash δb: Gash angle of the second gash δc: Gash angle of the third gash

Claims

1. An end mill characterized in that, in an end mill having three or more odd-numbered gashs at the tip of the tool body to form three or more odd-numbered bottom cutting edges, one of the odd-numbered bottom cutting edges is formed to reach the center of rotation, while the other bottom cutting edges are formed not to reach the center of rotation, the size of the gash provided in relation to each of the bottom cutting edges is adjusted to bring the center of gravity of the tool body closer to the axis of rotation.

2. An end mill according to claim 1, characterized in that, when adjusting the size of the gash provided corresponding to each bottom cutting edge, the inclination angle in the depth direction and / or the opening angle in the radial direction of the gash provided corresponding to each bottom cutting edge are adjusted to bring the center of gravity of the tool body closer to the axis of rotation.

3. An end mill according to claim 2, characterized in that the inclination angle in the depth direction and / or the opening angle in the radial direction of the gash forming the bottom cutting edge behind the rotational direction of the bottom cutting edge formed to reach the rotational center is increased, thereby bringing the center of gravity of the tool body closer to the rotational axis.

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