JP2003191119A - Throwaway tip for ball end mill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent variations in a machining diameter and machining accuracy even when a worn tip is reground for reuse, to prevent chattering in machining near a wall, and to allow lift machining. <P>SOLUTION: The throwaway tip comprises a tabular body provided with a half-arced plate like tip cutting edge part 2. In the tip cutting edge part 2, a quarter-arced cutting edge is provided on a ridgeline part of a flank relief 3 and a cutting face 4 in each of a front side and back side of the tabular body partitioned by a bisector o of the tip cutting part 2. Linear short cutting edges 6 in parallel with the bisector o as seen from above are formed in respective rear sides of the quarter-arced cutting edges 5. Inclined cutting edges 8 gradually approaching the bisector o as it separates from a connection 7 with the linear short cutting edge 6 as seen from above are formed in respective rear sides of the linear short cutting edges 6. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throw-away tip for a ball end mill used for machining a mold or the like.

[0002]

2. Description of the Related Art An end mill is a type of milling tool and has a wide range of uses such as bottom cutting, contour profiling, and grooving with a cutting edge on the outer periphery. Among them, a ball end mill having a R-shaped cutting edge is a tool that can be machined in all directions including three-dimensional machining such as dies including bumping.

Conventionally, as a throw-away tip mounted on such an end mill, as shown in FIG. 4, a throw-away tip 20 having an arc plate-shaped cutting edge portion 21 that exceeds a half arc is shown in FIG. As described above, the throw-away tip 30 including the half-arc plate-shaped tip cutting edge portion 31 and the rectangular plate-shaped rear cutting edge portion 32 is used.

[0004]

However, the above-mentioned conventional techniques have the following problems.

First, the former throw-away tip 20 having an arc-plate-shaped cutting edge portion 21 that exceeds a half arc is
When the cutting edge (and its flank surface) is re-polished when the cutting edge is blunted due to wear, the result of the re-polishing of the cutting edge is shown in FIG.
As shown in, there is a problem that the machining diameter changes and the machining accuracy deteriorates.

Further, the tip cutting edge portion 31 having a half arc plate shape.
In the latter throw-away tip 30 having the rectangular plate-shaped rear cutting edge portion 32, since the rear cutting edge portion 32 is long,
There was a problem that chattering was likely to occur during processing near the wall, and a problem that pulling processing could not be performed.

The present invention has been made in view of these problems of the prior art.
Since the worn tip is reused, the processing diameter and processing accuracy do not change even if it is re-polished, and the object is to prevent chattering at the processing near the wall and to enable pulling processing.

[0008]

In order to solve the above problems, a ball end mill according to a first aspect of the present invention comprises a plate-like body having a half arc plate-shaped tip cutting edge portion, and the tip cutting edge portion has Is provided with a quarter arc cutting edge formed on the ridge of the flank and the rake face on each of the front side and the back side of the plate divided by the bisector. To form a straight short blade parallel to the bisector in plan view on the rear side of each arcuate cutting edge, and to separate from the connection point with this straight short blade on the rear side of each straight short blade. Therefore, it is characterized in that an inclined blade is formed so as to gradually approach the bisector in a plan view.

According to such a construction, when the cutting edge is re-polished by forming the straight short blade, the processing diameter does not change and the processing accuracy is high. Further, since the contact width between the standing wall and the cutting edge is small at the time of machining near the wall, the cutting resistance is small and it is difficult to chatter. Further, pulling up is also possible by providing the inclined blade on the rear side of the straight short blade.

Further, in the throw-away tip for a ball end mill according to claim 2, a rake face inclined along the quarter arc cutting edge in the direction of the bisector is formed with a negative rake angle. Is characterized by.

According to this structure, when the flank is polished when the cutting blade is re-polished, the height of the cutting edge is increased and the rake face can be polished. That is, the chip processing performance can be improved by re-polishing the cutting edge and polishing the rake face to remove the concave portion due to chip wear.

Next, the throw-away tip for a ball end mill according to claim 3 is characterized in that the length of the straight short blade parallel to the bisector is 0.5 mm to 2 mm.

With such a structure, it is possible to more reliably achieve the effect of increasing the processing accuracy without changing the processing diameter when re-polishing the cutting edge, and the effect of preventing chattering during processing on the wall.

That is, if the length of the straight short blade is less than 0.5 mm, the straight cutting edge may be removed by re-polishing and the machining diameter may change. Chattering may occur during processing.

The throw-away tip for a ball end mill according to claim 4 has a negative rake angle of 3 on the rake face.
It is characterized by being in the range of 10 ° to 10 °.

According to this structure, the cutting edge is re-polished and the rake face is ground to remove the concave portion due to chip wear, so that the action of improving chip disposal performance can be achieved more reliably. Furthermore, it is effective in suppressing chattering.

That is, when the negative rake angle of the rake face is less than 3 °, sufficient polishing margin tends not to be obtained, while when it exceeds 10 °, chattering may occur easily.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

1 to 3 show a throw-away tip for a ball end mill according to this embodiment (hereinafter, simply referred to as a tip).
1 is shown.

In these drawings, reference numeral 2 is a tip cutting edge portion,
o is a bisector of the tip cutting edge portion 2, 3 is a flank surface, 4 is a rake surface, 5 is a quarter-arc cutting edge, 6 is a short straight blade, 7 is a connecting point, and 8 is an inclined blade. Show.

The tip 1 is a plate-like body having a half-arc-shaped tip cutting edge portion 2.

The tip cutting edge portion 2 is provided with a flank 3 and a rake face 4 on each of the front side and the back side divided by the bisector o.

The flank 3 and the rake face 4 are provided on one side of the bisector o and on the other side of the bisector o.
It has a rotational symmetry of 180 ° about the rotation axis.

Further, the tip cutting edge portion 2 is formed with a quarter arc-shaped cutting edge 5 at the ridge of the flank 3 and the rake face 4.

The rake face 4 is inclined along the quarter arc cutting edge 5 in the direction of the bisector o with a negative rake angle β. The negative rake angle β is preferably 3 ° to 10 ° for the reason described below.

Inside the rake face 4, there is formed a restraining surface 9 which is a stepped surface with respect to the rake face 4.

The restraining surface 9 comes into contact with a chip holding piece formed at the tip of a ball end mill body (not shown). Then, a bolt (not shown) for penetrating the chip in the thickness direction of the chip at a predetermined position of the constraining surface 9 (not shown).
A bolt hole 10 for inserting the through hole is formed.

The tip 1 is also provided with straight short blades 6 on the rear side of each of the quarter-arc cutting edges 5. The length w of the straight short blade 6 is 0.5 to 2 mm for the reason described below.
Is preferred.

Further, the tip 1 is provided with an inclined blade 8 on the rear side of each of the linear short waves 6 which approaches the bisector o in plan view as the distance from the connection point 7 with the linear short blade 6 increases. . The inclination angle θ of the inclined blade 8 with respect to the bisector o in plan view is 3 ° to 10 ° for the reason described later.
Is preferred.

FIG. 2 is an explanatory view for explaining the advantages of this embodiment. FIG. 2 is a plan view of the chip 1 and shows only one side of the bisector o. In FIG. 2, a removed portion 11 (hatched portion) is a portion removed by re-polishing the cutting edge of the chip 1.

As is apparent from FIG. 2, since the tip 1 is provided with the straight short blade 6, the machining diameter does not change even if the portion 11 is removed by the re-polishing of the cutting edge. Therefore, the processing accuracy can be maintained even after re-polishing.

Similar to FIG. 2, FIG. 3 is an explanatory view for explaining the advantages of this embodiment. FIG. 3 is a side view of the tip 1 from the flank 3 side.

In FIG. 3A, a portion 11 (hatched portion) is a portion to be removed by re-polishing the cutting edge of the chip 1. When the portion 11 is removed by this re-polishing cutting edge, the quadrant is removed. The edge height of the arcuate cutting edge 5 is increased. This is because, as described above, the rake face 4 is inclined along the quarter arc cutting edge 5 in the direction of the bisector o with a negative rake angle β. Then, the rake face 4 can be polished by an amount corresponding to the height of the cutting edge.

FIG. 3 (b) shows a state after the re-polishing of the cutting edge,
In the figure, a portion 12 (hatching portion) is a polishing margin of the rake face 4. By repolishing the cutting edge and polishing the portion 12 of the rake face 4 to remove the recess formed by chip wear, the chip disposal performance can be improved. At the same time, the height of the cutting edge can be made equal to that before polishing.

As another action of the tip 1, the tip 1 is moved by the inclined blade 8 which approaches the bisector o in a plan view as the distance from the connection point 7 with the straight short blade 6 increases. Pulling up can also be performed.

The tip 1 has a straight cutting edge 6 parallel to the bisector which has a length of 0.5 mm to 2 mm, so that when the cutting edge is re-polished, the working diameter remains unchanged. It is possible to more reliably achieve the effect of increasing the height and the effect of reducing chattering during processing on the wall.

That is, the length of the straight short blade 6 is 0.5 mm.
If it is less than 2, the straight cutting edge 6 may be removed by re-polishing and the machining diameter may change. On the other hand, if it is longer than 2 mm, chattering may occur during machining on the wall.

Further, the chip 1 can more reliably achieve the action of improving the chip disposal performance by setting the negative rake angle β of the rake face 4 to 3 ° to 10 °. Effective in suppressing chattering.

That is, when the negative rake angle β of the rake face 4 is less than 3 °, sufficient polishing margin cannot be obtained, while when it exceeds 10 °, chattering is likely to occur.

Further, when the inclination angle θ of the inclined blade 8 with respect to the bisector o in plan view is less than 3 °, the tip 1 may be apt to chatter during cutting, while 10
If it exceeds 0, the inclined blade 8 may be easily chipped during the pulling process.

Although the embodiment of the present invention has been illustrated above, it goes without saying that the present invention is not limited to this embodiment. The present invention can have any form without departing from the object of the invention.

[0042]

As described above, according to the throw-away tip for a ball end mill of the present invention, it is made of a plate body having a half arc plate-shaped tip cutting edge portion, and the tip cutting edge portion is On each of the front side and the back side of the plate body divided by the bisector, a quarter arc cutting edge formed on the ridge of the flank and the rake face is provided, and this quarter circle A straight short blade that is parallel to the bisector in a plan view is formed on the rear side of each arcuate cutting edge, and a flat surface is formed on each rear side of the straight short blade as the distance from the connection point with this straight short blade increases. By forming the inclined blade that gradually approaches the bisector visually, the machining diameter does not change and the machining accuracy is high when the cutting blade is re-polished. Further, since the contact width between the standing wall and the cutting edge is small at the time of machining near the wall, the cutting resistance is small and it is difficult to chatter. Further, pulling up is also possible by providing the inclined blade on the rear side of the straight short blade.

When a rake face is formed along the quarter arc cutting edge with a negative rake angle in the bisector direction, the flank face is re-polished when the cutting edge is reground. By polishing, the height of the cutting edge rises, and the rake face can be polished, and by re-polishing the cutting edge, the rake face is polished to remove the concave portion due to chip wear, so that the chip processing performance can be improved.

When the length of the straight short blade parallel to the bisector is set to 0.5 mm to 2 mm, the working diameter does not change when the cutting blade is re-polished, and the working accuracy is improved. It is possible to more reliably achieve the function of preventing chattering during processing on the wall.

The negative rake angle of the rake face is 3 °.
When it is set to -10 °, the action of improving the chip processing performance can be achieved more reliably by removing the concave portion due to chip wear by polishing the rake face together with re-polishing of the cutting edge. Effective in suppressing chattering.

[Brief description of drawings]

FIG. 1 shows a throw-away tip for a ball end mill according to an embodiment of the present invention, (a) is a perspective view, (b) is a plan view,
(C) is a left side view of (b), (d) is a bottom view of (b).

FIG. 2 is an explanatory diagram of re-polishing a cutting edge of the throw-away tip for a ball end mill of FIG.

FIG. 3 is an explanatory view of re-polishing a cutting edge and polishing a rake face of the throw-away tip for a ball end mill of FIG. 1, (a) is a re-ground portion of the cutting edge, and (b) is a diagram.
The polished portion of the rake face is shown.

FIG. 4 is a plan view of a ball end mill using a conventional throw-away tip.

FIG. 5 is a plan view of a ball end mill using another conventional throw-away tip.

FIG. 6 is an explanatory diagram for showing a problem of the throw-away tip of FIG.

[Explanation of symbols]

Throw-away tip for 1-ball end mill 2 Tip cutting edge 3 flank 4 rake face 5 quarter arc cutting edge 6 straight short blade 7 connection points 8 inclined blades 9 Restraint surface 10 bolt holes 11 (removed by re-polishing the cutting edge) 12 (polishing margin of rake face) o Bisecting line w Straight short blade length β Negative rake angle of rake face θ Angle of inclination of inclined blade

Claims (4)

[Claims] 1. A plate-like body provided with a half-arc plate-like tip cutting edge portion, wherein the tip cutting edge portion has a front side and a back side of the plate-shaped body divided by its bisector. Provided on each side with a quarter-arc cutting edge formed on the ridge of the flank and rake face,
A straight short blade that is parallel to the bisector in a plan view is formed on the rear side of each of the quarter arc cutting edges, and the straight short blade is connected to the straight short blade on the rear side of each straight short blade. A throw-away tip for a ball end mill, characterized in that an inclined blade is formed so as to gradually approach the bisector in a plan view as the distance from the point increases. 2. A ball end mill for a ball end mill according to claim 1, wherein a rake face inclined along the quarter arc cutting edge in the direction of the bisector is formed with a negative rake angle. Throw-away tip. 3. The throw-away tip for a ball end mill according to claim 1, wherein the length of the straight short blade parallel to the bisector is 0.5 mm to 2 mm. 4. The negative rake angle of the rake face is 3 ° to 10 °.
The throw-away tip for a ball end mill according to claim 2, wherein