JPH0615921U - Ball end mill and its cutting edge insert - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve fracture resistance by improving the cutting edge configuration on the arc edge 5 of the cutting edge. [Structure] The cutting edge tip 1 has a substantially triangular surface 3 having a central mounting hole 4 due to the presence of three arc side surfaces 2. A chamfered surface 7 is formed on the substantially triangular surface 3 side along the arc cutting edge 5 and at the apex angle portion where the belt-shaped surface 6 intersects. The strip surface 6 and the chamfer surface 7 are formed by the negative inclination angles α ₁ and α ₂ , but the inclination angle α ₂ of the chamfer surface 7 is stronger than the inclination angle α ₁ and thus The cutting edge 8 is formed. The cutting edge tip 1 is a tip seat 11 of the tool body 10.
A ball end mill is constructed by being screwed in. The arc-shaped side surface 2 constitutes a rake surface on cutting, and the strip-shaped surface 6 and the remaining substantially triangular surface 3 constitute a primary flank surface and a secondary flank surface on cutting, respectively.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a ball end mill and a cutting edge tip for the ball end mill, and more particularly, to enable effective utilization of the cutting edge of the cutting edge tip.

[0002]

[Prior art]

 Conventionally, as this type of ball end mill, for example, a generally triangular plate-shaped cutting edge tip having three arc side surfaces is incorporated into a tool body, and one of the arc side surfaces serves as a rake surface for cutting. Japanese Utility Model Publication No. 64-6171 is disclosed. Further, in the cutting edge tip seen in this publication, a chamfered surface forming a non-cutting edge is formed on the rake face side of the apex portion.

[0003]

[Problems to be solved by the device]

 However, the cutting edge tip forming the chamfered surface on the rake face side has a problem that the rake angle and the clearance angle make the clearance angle unnecessarily large and are likely to be chipped.

Therefore, in the present invention, the structure of the flank face and the chamfer face is improved to increase the chip strength.

[0005]

[Means for Solving the Problems]

 The present invention has been made in view of the above points, and a mounting hole is formed at the center of a substantially triangular surface formed by the existence of three arc side surfaces, and the arc side surfaces are cut rake surfaces. It is intended to improve the cutting edge tip for ball end mills used as.

That is, a strip-shaped surface having a negative inclination angle α ₁ is formed along an arc edge having a radius of curvature R on the substantially triangular surface, and the apex angle portion where the strip-shaped surfaces intersect is The chamfer surface is formed with a negative inclination angle α _{2 which} is stronger than the inclination angle α ₁ . Therefore, the intersection ridge formed by the chamfer surface and the circular arc side surface constitutes a non-cutting edge so as to prevent wear damage of the circular arc ridge of the adjacent corner during cutting.

The cutting edge tip constitutes a ball end mill by being screwed in the tip seat of the tool body.

[0008]

[Action]

Since the cutting edge tip according to the present invention is formed such that the strip surface and the chamfer surface having the negative inclination angles α ₁ and α ₂ are formed on the substantially triangular surface side, the rake angle is a regular angle. However, the edge strength can be increased. In particular, since this chamfer surface is on the flank surface side during cutting, the non-cutting edge substantially exists on the rake surface side, which is effective for maintaining strength.

[0009]

【Example】

 An embodiment of the ball end mill of the present invention and its cutting edge tip will be described below with reference to the drawings.

FIGS. 1 to 4 show a cutting blade tip 1, which has a substantially triangular surface 3 due to the presence of three arc-shaped side surfaces 2. The arcuate side surface 2 constitutes a rake surface for cutting, and has a radius of curvature R of, for example, R = 5 to 20 mm, and an inclination angle θ thereof, for example, θ = 0 ° to 20 °. It On the other hand, the above-mentioned substantially triangular surface 3 constitutes an upper cutting flank, and a mounting hole 4 is formed in the center thereof, and an inclination angle α is formed along the arc cutting edge 5 A strip 6 having ₁ is formed. Further, a chamfer surface 7 having a negative inclination angle α _{2 having} a stronger inclination than the inclination angle α ₁ is formed at the intersecting apex angle portion of the strip-shaped surface 6. In this case, the inclination angles α ₁ and α ₂ are usually set in the range of α ₁ = −3 ° to −15 ° and α ₂ = −5 ° to −20 °, and the strip surface 6 and the chamfer surface 7 are in terms of the width _{W 1, W 2, W 1} = 0.5~5mm, is set at about W ₂ = 0.5 to 5 mm. The chamfer surface 7 intersects the arc side surface 2, and the intersecting edge forms a non-cutting edge 8 with respect to the arc cutting edge 5.

Further, FIGS. 5 to 7 show a ball end mill in which the cutting edge tip 1 is incorporated in the tip seat 11 of the tool body 10. In this case, the cutting edge tip 1 is fixed in the tip seat 11 by the set screw 12, the arc side surface 2 constitutes a rake surface for cutting, and the strip surface 6 and the substantially triangular surface remaining in the center. 3 respectively form a primary flank and a secondary flank.

In the axial direction of the tool body 10, a peripheral cutting edge tip 13 that enables deep groove cutting and the like is provided. In the illustrated case, the outer peripheral cutting edge chip 13 is in the shape of a diamond plate, has a mounting hole 14 in the center thereof, and is screwed by a set screw 15.

[0013]

[Effect of device]

According to the present invention, as described above, the chamfer surface 7 has a negative inclination angle α at the flank surface of the cutting edge tip 1 on the side of the substantially triangular surface 3 and at the apex angle portion where the belt surface 6 intersects. It is formed with ₁ and α ₂ . Therefore, the cutting edge angle at the arc cutting edge 5 is increased to increase the cutting edge strength. As a result, the chipping resistance of the cutting edge tip 1 is enhanced, and it is effective when incorporated into the tool body 10 of the ball end mill and involved in cutting.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a cutting edge tip for a ball end mill of the present invention.

FIG. 2 is a side view.

FIG. 3 is a partially enlarged cross-sectional view taken along the line AA in FIG.

4 is a partially enlarged cross-sectional view taken along the line BB in FIG.

FIG. 5 is a partial front view showing an embodiment of the ball end mill of the present invention.

FIG. 6 is a bottom view.

FIG. 7 is a partial side view.

[Explanation of symbols]

 1 Cutting Edge Chip 2 Arc Side Surface 3 Approximately Triangular Surface 4 Mounting Hole 5 Arc Cutting Edge Ridge 6 Band Surface 7 Chamfer Surface 8 Non-cutting Edge 10 Tool Body 11 Tip Seat 12 Set Screw

Claims (2)

[Scope of utility model registration request] 1. A mounting hole 4 is formed in the center of a substantially triangular surface 3 formed by the presence of three arc side surfaces 2, and the arc side surface 2 constitutes a rake surface for cutting. In the cutting edge tip for a milling tool, a strip surface 6 having a negative inclination angle α ₁ is formed on the substantially triangular surface 3 along an arc cutting edge 5 having a radius of curvature R.
Moreover, a chamfer surface 7 having a negative inclination angle α _{2 having} a stronger inclination than the inclination angle α ₁ is formed at the intersecting apex angle portion of the strip-shaped surface 6, and the intersection edge formed by the chamfer surface 7 and the circular arc side surface 2 is formed. A cutting edge tip for a ball end mill, which has a non-cutting edge 8 for preventing abrasion damage of an arc edge of an adjacent corner during cutting. 2. The cutting edge tip 1 according to claim 1 is screwed in the tip seat 11 of the tool body 10 so that the arc side surface 2 constitutes a rake face during cutting and the strip shape A ball end mill in which the surface 6 constitutes the primary flank and the substantially triangular surface 3 remaining in the center constitutes the secondary flank.