JP2001334406A - Throwaway type ball end mill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem of being unable to carry out high precision finishing work as a chip moves at the time of mounting the chip or in the middle of cutting the chip, causing a loss or chattering of the chip, lowering of a manufacturing yield, etc. SOLUTION: A metal member is arranged on an inwall part of a clamp hole of a cutting chip on a throw away type ball end mill to fix the cutting chip by screwing a clamp screw on the other side of a clamp piece through the clamp hole from one side of the clamp piece by providing the two clamp pieces so that they face against each other on a head end part of a ball end mill main body and arranging the cutting chip having the clamp hole between these clamp pieces so that it makes contact with the ball end mill main body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a throw-away type ball end mill.

[0002]

2. Description of the Related Art An end mill is a kind of slicing tool and has a cutting edge on its outer periphery and has a wide range of uses such as bottom cutting, side cutting, contour copying, and groove cutting. Among these end mills, a replaceable cutting edge (a throw-away type) end mill is used by attaching a replaceable cutting edge to a tool tip, and is selected according to various shapes in die machining and component machining.

[0003] Among them, a ball end mill having an R-shaped tip cutting edge is a tool that can perform machining in all directions including thrusting by three-dimensional machining such as a die. As a ball end mill for finishing, one chip is used. The type in which the blade diameter tolerance and the R precision are fixed with being pinched and fixed at the tool tip, has become mainstream.

That is, as shown in FIGS. 4 and 5,
In such a throw-away type ball end mill, two clamp pieces 12, 1
2 are provided facing each other, a chip 13 is arranged between the two clamp pieces 12, 12 and fixed with a clamp screw 14.

[0005] In this case, in order to perform high-precision finishing, it is necessary to increase the blade diameter tolerance and the R accuracy.
For this purpose, for example, in Japanese Utility Model Laid-Open Publication No. 6-53012, the constraint surface 15 of the tip 13 in the end mill body 11 is set to V
The finishing accuracy for the workpiece is improved by increasing the accuracy when attaching the chip 13 to the shape of a letter.

[0006]

However, in this conventional throw-away type ball end mill, as shown in FIGS. 6 and 7, the inner diameter of the clamp hole 16 is considerably larger than the outer diameter of the clamp screw 14 due to a dimensional error. In the event that the tip 13
However, there is a problem that high-precision finishing cannot be performed.

Further, if the tip 13 moves during the cutting process, the tip 13 may be broken or chattered, and the cutting operation must be interrupted, resulting in a problem that the working efficiency is poor. FIG. 6 shows a normal mounting state of the chip 13, and FIG. 7 shows a state when the chip 13 is positioned.

[0008] In order to prevent the tip 13 from moving during such mounting or cutting, a clamp hole 16 is required.
In addition, the dimensional tolerance of the clamp screw 14 must be strict, which causes problems such as an increase in manufacturing cost due to a decrease in manufacturing yield.

Further, while the tip 13 is formed of a cemented carbide, cermet, ceramic or the like, the clamp screw 1
4 is made of carbon steel or alloy steel, the tip 13
When the attachment and detachment are repeatedly performed, the clamp screw 14 is worn, and there is a problem that the mounting accuracy of the tip 13 is reduced.

[0010] The present invention has been made in view of such problems of the conventional apparatus, and the chip moves during the mounting of the chip or during the cutting, so that high-precision finishing cannot be performed or the chip is damaged. It is an object of the present invention to provide a throw-away type ball end mill which solves the conventional problems of causing chipping, chattering, lowering the production yield, and lowering the chip mounting accuracy during repeated use.

[0011]

To achieve the above object, a throw-away type ball end mill according to claim 1 is provided with two clamp pieces at the tip of a ball end mill body so as to face each other. A cutting tip having a clamp hole is provided so as to abut the ball end mill body between the pieces, and a clamp screw is threaded from one side of the clamp piece through the clamp hole to the other side of the clamp piece. In a throw-away type ball end mill for fixing the cutting tip, a metal member is disposed on an inner wall portion of a clamp hole of the cutting tip.

In the above throw-away type ball end mill, it is desirable that the metal member is made of copper or aluminum or an alloy of these metals.

In the throw-away type ball end mill according to the third aspect, two clamp pieces are provided at the tip of the ball end mill body so as to face each other, and between the clamp pieces, the ball end mill body is brought into contact. A throw-away type ball in which a cutting tip having a clamp hole is provided, and the cutting tip is fixed by screwing a clamp screw through the clamp hole from one side of the clamp piece to the other side of the clamp piece. In the end mill, a cutting portion is provided in which a part of the peripheral end side of the ball end mill body with which the cutting tip comes into contact is provided, and the cutting tip is also brought into contact with this cutting portion so that a part of the cutting tip also comes into contact. The contact portion with the ball end mill main body is formed in a hook shape.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a view showing a cutting tip portion of a throw-away type ball end mill according to each claim, and FIG. 2 is a sectional view of the same.

In FIGS. 1 and 2, 1 is a ball end mill main body, 2 is a cutting tip, 3 is a clamp screw, 4 is a clamp piece, and 5 is a clamp hole.

The end mill body 1 has a circular, elliptical or polygonal cross section, and has two clamp pieces 4 on both sides of the tip.
4 are provided so as to face each other in the length direction of the main body 1.

[0017] The two clamp pieces 4, 4 are
Are formed at a predetermined interval so as to be substantially the same as or slightly wider than the thickness of the substrate. Further, the length is formed so that the cutting tip 2 slightly protrudes from the front end portion and the peripheral edge portion.

On one side of the two clamp pieces 4, 4, a screw hole 6a through which the knurl screw 3 is inserted is provided, and on the other clamp piece 4, a screw hole 6a into which the clamp screw is screwed is provided. ing.

The tip of the clamp piece 4 is provided in an arc shape such that a cutting tip 2 described later projects substantially evenly from the tip of the clamp piece 4.

The end mill body 1 has two clamp pieces 4,
The chip contact portion 1a located between the four is formed in a planar shape so as to be a constraint surface of the cutting tip 2 when the cutting tip 2 is attached.

The end mill body 1 is made of, for example, carbon steel.

A cutting edge portion 2a formed in an arc shape so that one end side of the cutting tip 2 slightly protrudes from the clamp pieces 4 and 4 of the end mill body 1, and is formed continuously with the cutting edge portion 2a. A bottom portion 2b is formed in a straight line so as to contact the flat portion 1a of the end mill body 1 in the cut lamp pieces 4, 4.

The bottom 2b is positioned in contact with the restraining surface 1a of the end mill body 1. A cutout is formed by cutting off one end of the constraint surface 1a, and a protrusion 2c is formed in the cutout so that a part of the lower end of the cutting tip 2 projects, and the lower end of the cutting tip 2 becomes hook-shaped. It is formed as follows. The cutting tip 2 can be stably fixed to the ball end mill main body by forming the cutting tip 2 in such a hook shape as the restraining surface in this way.

At a substantially central portion of the cutting tip 2, a clamp hole 4 for fixing the cutting tip 2 is provided at a clamp piece 4, 4 portion with a clamp screw 3.

The cutting tip 2 is made of, for example, a cemented carbide, a cermet, a coated cemented carbide, ceramics, or an ultra-high pressure sintered body.

A metal member 7 made of copper, aluminum, or an alloy of these metals is provided in the clamp hole 5. The metal member 7 is not limited to copper or aluminum or an alloy thereof, and may be formed of lead, nickel, zinc, or an alloy thereof. The metal member 7 is formed, for example, of a hardness of HRF90 or less.

FIGS. 3A and 3B show metal members. FIG.
FIG. 3A is a view of the metal member viewed from one end, and FIG.
(B) is the figure seen from the side. The metal member 7 has substantially the same length as the cutting tip 2, and is provided with a split 7 b on a part of the wall surface so as to reduce the outer diameter when inserted into the clamp hole 5. In addition, a screw through hole 7a whose inner diameter is substantially the same as or slightly smaller than the outer diameter of the clamp screw 3 is formed. The metal member 7 has a thickness of, for example, 0.5 to 2.
It is formed with a thickness of about 0 mm.

This metal member 7 is pressed into the clamp hole 5. That is, the outer diameter of the metal member 7 is slightly larger (about 0.01 to 0.1 mm in diameter) than the clamp hole 5 and is driven with a plastic hammer.

The clamp screw 3 is made of, for example, carbon steel or alloy steel.

In such a configuration of the end mill body 1 and the cutting tip 2, the cutting tip 2 is interposed between the two clamp pieces 4, and the clamp hole 2 a of the cutting tip 2 penetrates from one clamp piece 4 side. Then, the cutting tip 2 is fixed by screwing the clamp screw 3 into the screw hole 6 b of the other clamp piece 4. In this case, when the clamp screw 3 passes through the clamp hole 5, the light alloy made of brass, aluminum, or the like is deformed, and the clamp hole 5 and the clamp screw 3
The cutting tip 2 can be fixed by the clamp screw 3 so that there is no gap between the cutting tip 2 and the cutting tip 2.

Accordingly, when the clamp screw 3 is inserted into the clamp hole 5 of the cutting tip 2 and fixed while the hook-like portion 2c of the cutting tip 2 is in contact with the restraining surface 1a of the end mill body 1, the cutting tip 2 Is not displaced, and the positional accuracy of the mounting of the cutting tip 2 can be improved.

As described above, after the cutting tip 2 is once fixed, there is no gap between the clamp hole 5 and the clamp screw 3, so that chatter and runout do not occur during the cutting operation.

[0033]

As described above, according to the throw-away type ball end mill according to the first aspect, since the metal member is arranged and fixed on the inner wall portion of the clamp hole of the cutting tip, the clamp hole and the clamp screw are formed. , The cutting tip can be accurately positioned and fixed to the constraint surface of the end mill main body, and the accuracy of the mounting position of the cutting tip can be improved. In addition, the light alloy serves as a cushioning material, so that the movement of the chip during processing is suppressed, breakage and chatter due to the movement of the chip can be prevented, and the finishing accuracy of cutting the workpiece can be improved. Further, wear of the clamp screw can be prevented, and the mounting accuracy can be maintained for a long time.

According to the throw-away type ball end mill of the third aspect, a cut-out portion is provided by removing a part of the ball end mill body on the peripheral edge side with which the cutting tip contacts, and the cut portion is also provided with the cut-off portion. Since the contact portion of the cutting tip with the ball end mill main body is formed in a hook shape so that a part of the tip comes into contact, the cutting tip 2 can be stably fixed to the ball end mill main body.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a throw-away type ball end mill according to each claim.

FIG. 2 is a sectional view showing one embodiment of a throw-away type ball end mill according to each claim.

FIGS. 3A and 3B are views showing a metal member used in the throw-away type ball end mill according to claim 1, wherein FIG. 3A is a view from one end and FIG. 3B is a view from a side.

FIG. 4 is a view showing a conventional throw-away type ball end mill.

FIG. 5 is a view showing another conventional throw-away type ball end mill.

FIG. 6 is an enlarged view showing a cutting tip portion in a conventional throw-away type ball end mill.

FIG. 7 is a view showing a state where a cutting tip is misaligned in a conventional throw-away type ball end mill.

[Explanation of symbols]

1: ball end mill, 2: cutting tip, 3: clamp screw, 4: clamp piece, 5: clamp hole

Claims (3)

[Claims] 1. A cutting tip having a clamp hole is provided at a tip end portion of a ball end mill main body so as to face each other, and a clamp hole is provided between the clamp pieces so as to abut on the ball end mill main body. In a throw-away type ball end mill that penetrates the clamp hole from one side of the clamp piece and screws a clamp screw to the other side of the clamp piece to fix the cutting tip, an inner wall portion of the clamp hole of the cutting tip A throw-away type ball end mill, wherein a metal member is disposed on the ball end mill. 2. The indexable ball end mill according to claim 1, wherein the metal member is made of copper, aluminum, or an alloy of these metals. 3. A cutting tip having a clamp hole is provided at a tip portion of a ball end mill main body so as to face each other, and a clamp hole is provided between the clamp pieces so as to contact the ball end mill main body. In a throw-away type ball end mill for fixing a cutting tip by screwing a clamp screw to the other side of the clamp piece through the clamp hole from one side of the clamp piece, the ball end mill with which the cutting tip abuts A cut-out portion is provided in which a part of the peripheral edge side of the main body is removed, and a contact portion of the cutting tip with the ball end mill main body is formed in a hook shape so that a part of the cutting tip also contacts the cut-out portion. A throw-away type ball end mill characterized by being formed.