JPH08281513A - Throw away type end mill - Google Patents

Abstract

PURPOSE: To facilitate the attaching of a suitable corner R (round) edge to a cutting edge tip by providing a V-shaped slit extending in the axial direction of a holder body in its tip part, and sandwichedly holding a tip having a cutting edge at a tip edge protruding from the slit in the V-shaped slit. CONSTITUTION: A cutting edge tip 3 sanclwichedly held in a V-shaped slit 2 is equipped with two sheets of outer peripheral edges 5 generated by the rotation of a tool; an end cutting edge 6 which has a slight concave grade with the outer peripheral edge 5 but is about vertically arranged; and two sheets of corner R (round) edges 7 composed of an about quarter circular arc which comes into contact with the outer peripheral edge 5 and the end cutting edge 6 and is about 5mm in radius. Since the outer peripheral edge 5 starts from the tip apex corner of the cutting edge tip 3 and extends in an axial direction, in the tip part of the outer peripheral edge 5, the thickness of the tip wholly has charge of strength. In the case where the corner R edge 7 being about 4 mm or 6mm in a radius is necessary for the cutting edge tip 2, the corner R edge which has the same size and varies only in the value of corner R can be utilized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throw-away type end mill equipped with a corner edge, which is mainly used for engraving a cavity of a mold.

[0002]

2. Description of the Related Art As an example of a throw-away type end mill having a corner edge, a radius end mill having a circular cutting edge tip made of cemented carbide as shown in FIG. This is a corner blade using a circular tip, which enhances the cutting edge strength to prevent chipping and chipping during flat surface cutting and is effective in cutting, and a throw-away tip can be used. Even if the cutting edge tip is damaged, there is an advantage that the cutting edge tip can be regenerated at a small cost only by exchanging the tip.

[0003]

However, in the conventional example, since it is originally intended for plane cutting, in the case of shape transfer, the accuracy of the machined arm is affected by the problem of the mounting angle of the cutting edge tip. There is a problem, and in the case of three-dimensional copying cutting, there is a problem that vertical feed cutting cannot be performed because there is no cutting edge at the tool rotation center. There is also a problem that the holder main body differs depending on the corner value.

[0004]

SUMMARY OF THE INVENTION The present invention has been made based on the above background, and can be used for the transfer of the round shape of an end mill or the molding of a curved surface by three-dimensional contour cutting and has a relatively large diameter. Even in this case, the present invention provides a throw-away type end mill with a corner edge, in which machining accuracy and economic efficiency are paralleled.

[0005]

In order to achieve the above object, the present invention provides a V-shaped slit extending in the axial direction of the holder body at the tip of the holder body, and the slit is provided in the slit. A tip having a cutting edge is sandwiched between the tip edges protruding from the cutting edge, and an outer peripheral blade is emitted in the axial direction from the tip apex angle of the cutting edge tip, and a peripheral edge is formed on a diagonal line including the axial center from the apex angle emitted from the outer peripheral blade And a cutting edge tip having a bottom blade positioned substantially perpendicular to the bottom blade, and a bottom blade corner having an outer peripheral edge and a corner edge having an approximately 1/4 circular arc in contact with the bottom edge. The blade has a gash angle of 30 to 45 °, and is configured such that an ungashed strip is left in a width of 0.1 to 1 mm parallel to the outer peripheral blade.

[0006]

The V-shaped slit extending in the axial direction is provided at the tip of the holder body to sandwich the cutting edge chip, so that one cutting edge chip has two corner corner blades. Can be provided. Further, since the outer peripheral edge extends from the tip apex angle of the cutting edge tip and extends in the axial direction, the entire tip thickness contributes to the enhancement of the cutting edge strength at the outer peripheral edge tip portion having the largest cutting load. Further, the above effect can be further enhanced by using a right-handed helix blade having excellent machinability. Further, by increasing the gash angle of the bottom blade to 30 to 45 °, it becomes possible to expedite the elimination of chips and further improve the machinability. In addition, by leaving a non-gashed strip with a width of 0.1 to 1 mm parallel to the outer peripheral blade, the precision of the cutting edge is maintained and a uniform sharpness is secured. Further, the corner value can be changed only by replacing it with a cutting edge tip having a required value.

[0007]

The present invention will be described below based on its embodiments. FIG. 2 is a front view of a throw-away type end mill according to the present invention, in which 1 is a holder main body made of alloy steel, and a cutting edge tip 3 having a cutting edge at a tip portion protruding from a slit 2 at a tip portion thereof. V-shaped slit 2 in the axial direction of the holder main body 1 so that it can be clamped, and the other end has a diameter of 2
A 5 mm shank 4 is provided.

As shown in FIGS. 3 to 5, the cutting edge chip 3 sandwiched between the V-shaped slits 2 has two outer peripheral blades 5 with a diameter of 20 mm created by the rotation of the tool, and the outer peripheral blade 5. Is a bottom blade 6 which has a slight middle slope and is arranged almost vertically
And two corner edge blades 7 having a radius of 5 mm, which are in contact with the outer peripheral blade 5 and the bottom blade 6, and which are substantially 1/4 arcs.
The axial length is 25 mm and the thickness is 5 mm.

Since the outer peripheral blade 5 extends from the tip apex angle of the cutting edge tip 3 and extends in the axial direction, the tip thickness of 5 mm at the tip portion of the outer peripheral blade 5 bears all the strength.
Further, a right-hand helix blade having a helix angle α = 8 ° is formed in the axial direction. The bottom blade 6 of the cutting edge tip 3 is provided with a gash angle θ at an angle of 35 °, but since the bottom blade 6 is provided diagonally from the tip apex angle of the cutting edge tip 3, strength due to gash The decrease in is slight. Also, the outer peripheral blade 5
In parallel with this, a non-gashed strip 8 having a width of about 0.2 mm is left. Generally, when a large Gash angle θ is taken, grinding streaks are left even on the outer peripheral blade during grinding with a grindstone, which impairs the cutting property and shape accuracy of the cutting edge. Here, the precision could be maintained by leaving the non-gashed portion as a strip.

When the cutting edge tip 2 requires a corner edge 7 having a radius of 4 mm or 6 mm, the same tip size with only the corner value changed can be used, and the entire tool can be replaced. It is also economically advantageous as compared with the case of doing.
When the throw-away end mill manufactured as described above was subjected to contour engraving of the mold material, the intermittent cutting state was relaxed due to the effect of the helical blade, and good machinability was exhibited. In addition, it was possible to perform cutting with extremely high precision without recognizing chipping of the chip.

[0011]

EFFECTS OF THE INVENTION According to the present invention, even if it has a relatively large diameter used for finishing of curved surface machining such as shape transfer and three-dimensional contour cutting, the cutting edge strength and the machinability are excellent, the machining accuracy is good, and the economy is high. It was possible to obtain a throw-away type end mill equipped with a corner with good performance.

[Brief description of drawings]

FIG. 1 shows a front view of a conventional example.

FIG. 2 shows a front view of one embodiment of the present invention.

FIG. 3 shows a front view of the cutting edge tip of FIG.

FIG. 4 shows a side view of FIG.

FIG. 5 shows a top view of FIG.

[Explanation of symbols]

 1 Holder body 2 Slit 3 Cutting edge tip 4 Shank 5 Peripheral edge 6 Bottom edge 7 Corner edge 8 Un-gashed line θ Gash angle α Twist angle

Claims (2)

[Claims] 1. A V-shaped slit extending in the axial direction of the holder body is provided at a tip portion of the holder body, and a chip having a cutting edge at a tip edge protruding from the slit is sandwiched in the slit to cut the holder body. To the outer peripheral blade in the axial direction from the tip apex angle of the blade tip, to the bottom blade corner and the bottom blade positioned substantially perpendicular to the outer peripheral blade on the diagonal line including the axis center from the tip apex angle emitted from the outer peripheral blade. A throw-away type end mill provided with a cutting edge tip equipped with a peripheral edge and a corner arc edge which is formed of an approximately 1/4 circular arc in contact with the bottom edge. 2. The throw-away type end mill according to claim 1, wherein the bottom blade has a gash angle of 30 to 45 °, and a non-gashed strip is left in a width of 0.1 to 1 mm parallel to the outer peripheral blade. Throw-away type end mill characterized by being configured as follows.