JPH08323527A - Throwaway end mill - Google Patents

Abstract

(57) [Summary] [Structure] A throw-away end mill E in which inserts A to D are detachably mounted by two or more blade rows, and a short side cutting edge is a bottom blade 4 at the tip of the end mill E and A cutting insert B having a long side cutting edge as a side edge 5 and a cutting insert A having a long side cutting edge as a bottom edge 4 and a short side cutting edge as a side edge 5 are mounted, and inserts in the same row [A, C and B, D] are arranged with a space S in the axial direction,
The indexable end mill E is arranged so that the machining of the gap portion is performed by the insert of another blade row. [Effect] The cutting efficiency is good, and the cutting edges of the inserts A to D are involved in the cutting without waste, so that the stress is sufficiently dispersed, and thus the rigidity of the inserts A to D and the tool body is also increased. Is.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throw-away end mill in which a cutting insert is removably attached to the outer periphery of a tool body, and in particular, the bottom of a hole is simultaneously cut by a bottom blade, and the arrangement of cutting inserts is devised. The present invention relates to a throw-away end mill with improved cutting efficiency.

[0002]

2. Description of the Related Art In throw-away end mills,
A plate-shaped cutting insert having a cutting edge portion is detachably attached to the outer periphery of the tip of a tool body that rotates around an axis.

FIG. 2 shows a conventional throw away end mill 20 according to another embodiment, which is configured to mount parallelogrammatic plate-shaped cutting inserts 21 to 23 having a short side and a long side, and a short side cutting edge on the tip side. Cutting insert 21
The cutting insert 22 with the long side cutting edge facing the tip side is attached to the tip of the tool.

Further, such a tool usually does not have a bottom blade, but a cubic or equilateral parallelogram cutting insert is mounted as in the invention of Japanese Utility Model Laid-Open No. 60-53420, and the bottom blade is dedicated. In some cases, the cutting insert of was attached to the tool tip.

[0005]

However, the above-mentioned conventional technique has the following problems.

That is, as shown in FIG. 2, a cutting insert 21 having a cutting insert 21 having a short side cutting edge directed to the tip side and a cutting insert 22 having a long side cutting edge directed to the tip side is attached to a tool tip (hereinafter, End mill)
In No. 0, the cutting edges of these cutting inserts 21 and 22 are not installed so as to be bottom blades, and in a protective sense that the tip of the tool body is not damaged at the bottom surface such as a hole. , Cutting insert 2 with the cutting edge facing the tip side
1 and 22 are installed.

Further, in this conventional end mill 20, two cutting inserts (hereinafter abbreviated as inserts) 21 and 23 each having a long side cutting edge installed along the axial direction almost do not overlap each other and are located at the front and rear positions. They were arranged in a relationship, so that the two inserts acted as if they were one insert.

Therefore, the three inserts 21-23
Although the cutting efficiency was low, the cutting edge per unit length received a large stress and the cutting edge was liable to be damaged, and the stress was insufficiently distributed to a specific part of the tool body. There is a problem that excessive stress is applied and the rigidity of the tool body is not so great.

Next, in the conventional end mill in which the insert for the bottom blade is attached to the tip of the tool, it is necessary to separately form a pocket for installing the insert for the bottom blade.
For this reason, the rigidity of the tip portion is lowered, and the space for forming the pocket is limited, so that there is a problem that the axial rake and the radial rake of the insert dedicated to the bottom blade cannot be freely set.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems of the prior art, and therefore improves the cutting efficiency in an end mill having a bottom blade for cutting the bottom of a hole. The purpose is to reduce the stress applied to the cutting edge of the insert per unit length, increase the strength of the tool body, and obtain an end mill with reliable machining.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems of the prior art, the present invention is a throw-away end mill in which inserts are detachably mounted by two or more rows of blades, and a short side is provided at the tip of the end mill. The cutting insert with the cutting edge as the bottom blade and the cutting insert with the long side cutting edge as the bottom edge are installed, and the inserts are arranged at intervals in the axial direction in one of the blade rows and the other of the blade rows. Then, there is provided a throw-away end mill in which inserts are arranged at positions corresponding to the above intervals.

[0012]

The end mill of the present invention having such a structure has
Of the two inserts mounted at the end of the end mill, the long side edge of one insert is the bottom edge and the short side edge is the side edge, and the short edge edge of the other insert is the bottom edge and the long edge edge is By using the blade as a side cutting edge, a bottom blade for cutting the bottom of a hole was formed without using a dedicated insert for the bottom blade. Therefore, the rigidity of the tip of the end mill is large, and the occurrence of chattering can be suppressed.

Further, since the inserts of the same row are mounted at intervals in the axial direction, and the processing of this interval portion is arranged so as to be overlapped by the inserts of the other blade rows, most of the work surface of the workpiece is cut. This means that the part of 2 is cut by two or more cutting edges, which improves the cutting efficiency.

That is, in the end mill of the present invention, since the cutting edge of the insert participates in the cutting without waste, the stress is sufficiently dispersed to the insert and the tool body, and the rigidity of the insert and the tool body is also increased.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an end mill E of the present embodiment, in which the plate-shaped inserts A to D are removably attached to the outer periphery of the tip end portion of a tool body that rotates around an axis.

The inserts A to D mounted on the end mill E have a parallelogram shape in plan view having short sides and long sides, and a cutting edge is formed on the ridge portion of the upper surface 1.
In addition, a seating surface is formed on the lower surface 2 so as to be fixed in a chip pocket 3 provided on the outer periphery of the tool body. These are one of the two blade rows formed on the end mill E. Two inserts A and C on the blade row 90
The two inserts B and D are arranged in a positional relationship of .degree., And the two insert rows B and D are arranged in substantially the same direction in the other blade row.

Among these inserts A to D, two inserts A and B are fixed to the tip of the end mill E, but one insert B has a short side cutting edge and a bottom edge 4
And the long side cutting edge is the side edge blade 5, and the other insert A
Has a long side cutting edge as a bottom blade 4 and a short side cutting edge as a side edge 5. Further, when the remaining inserts B and D whose long side cutting blades are the side surface blades 5 are fixed with an interval S in the axial direction behind the inserts A and B on the front end side, this interval portion Processing is arranged to be performed by inserts in other blade rows.

In the end mill E thus constructed, the long side cutting blade of the insert A fixed to the tip is the bottom blade 4, so that the hole bottom can be cut without using the insert dedicated to the bottom blade. Therefore, it is not necessary to make such a pocket in the past where a separate insert pocket had to be made to install a dedicated insert for the bottom blade, so the rigidity of the tip is secured and chattering etc. occurs. hard.

The two inserts A and B fixed to the tip respectively use both one of the long side cutting edge and one of the short side cutting edge for cutting, and further inserts [A, C and B, D in the same row]. ] Are mounted at intervals S in the axial direction, and the processing of this interval is arranged to be performed by the insert of another blade row, so many parts of the work surface of the workpiece are cut with two cutting edges. As a result, the cutting efficiency is improved, and the stress applied to the cutting edge per unit length is small and the stress is dispersed, so the rigidity of the insert and the tool body is also large.

Further, according to this embodiment, the bottoms of the holes can be cut by the inserts A to D having the same shape, and it is not necessary to use different types of inserts, which is convenient for use.

Although the end mill E having two blade rows has been described in the above embodiment, the present invention is not limited to such an end mill E, and an end mill having three or more blade rows. May be.

[0022]

As described above, the end mill of the present invention has the bottom blade for cutting the hole bottom without using the insert dedicated to the bottom blade. Therefore, the rigidity of the tip of the end mill is large, and the occurrence of chattering can be suppressed.

Further, since the inserts of the same row are mounted at intervals in the axial direction, and the processing of this interval portion is arranged so as to be overlapped by the inserts of other blade rows, many of the work surfaces of the workpiece are to be cut. This means that the part of 2 is cut by two or more cutting edges, which improves the cutting efficiency.

That is, in the end mill of the present invention, since the cutting edge of the insert participates in the cutting without waste, the stress is sufficiently dispersed to the insert and the tool main body, so that the rigidity of the insert and the tool main body is increased. It plays.

[Brief description of drawings]

FIG. 1 is a side view of a throw-away end mill according to an embodiment of the present invention.

FIG. 2 is a side view of a conventional throw away end mill.

[Explanation of symbols]

 A to D Cutting insert E Slow away end mill S Spacing 1 Upper surface 2 Lower surface 3 Chip pocket 4 Bottom blade 5 Side blade

Claims (1)

[Claims] 1. A throw-away end mill in which a parallelogrammatic plate-shaped cutting insert having a short side and a long side on the outer circumference of a tool body is detachably mounted by two or more rows of blades, and at the tip of the end mill, While installing the cutting insert with the short side cutting edge as the bottom blade and the long side cutting edge as the side edge, and the cutting insert with the long side cutting edge as the bottom edge and the short side cutting edge as the side edge, A throw-away end mill in which each cutting insert is arranged at intervals in the axial direction in the blade row, and the cutting inserts are arranged at positions corresponding to the above intervals in the other blade row.