JP3638033B2 - Throw-away end mill - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a throw-away end mill having a corner-alloy blade mainly used for engraving a cavity of a mold.
[0002]
[Prior art]
As an example of a throw-away end mill equipped with a corner-alloy blade, a radius end mill having a circular cutting edge tip made of a cemented carbide as shown in FIG. 1 attached to a holder body is commercially available. Uses inserts as corner edges to increase cutting edge strength, prevent chipping and chipping during flat cutting, and is effective for cutting, and throw-away inserts can be used. Even if there is, there is an advantage that it can be regenerated at a small cost of only chip replacement.
[0003]
[Problems to be solved by the invention]
However, in the conventional example, it is originally intended for plane cutting, and in the case of shape transfer, there is a problem in the accuracy of processing due to the problem of the mounting angle of the cutting edge tip. However, since there is no cutting edge at the center of tool rotation, there is a problem that vertical cutting cannot be performed.
There is also a problem that the holder body differs depending on the value of the corner alarm.
[0004]
[Object of the present invention]
The present invention has been made based on the background as described above, and can be used for curved surface forming such as transfer of the round shape of the end mill or three-dimensional profile cutting, and processing accuracy even if the diameter is relatively large. And a throw-away end mill with a corner-alloy blade that balances economic efficiency.
[0005]
[Means for solving problems]
In order to achieve the above-mentioned object, the present invention provides a slit extending in the axial direction at the tip of the holder body, sandwiching a chip having a cutting edge at the leading edge protruding from the slit, and An outer peripheral blade that originates from the tip apex angle at the tip in the axial direction, a bottom blade that is positioned substantially perpendicular to the outer peripheral blade on a diagonal line including the axis center from the apex angle emitted by the outer peripheral blade, and an outer peripheral blade at the bottom blade corner A throw-away end mill characterized in that a pair of corner-shaped blades each having a substantially 1/4 arc in contact with the bottom blade are provided, and the bottom blade has a gash angle of 30 to 45 °, It is configured so as to leave an ungashed strip with a width of 0.1 to 1 mm parallel to the blade.
[0006]
[Action]
Since the tip of the holder body is provided with a V-shaped slit extending in the axial direction and sandwiching the cutting edge chip, a single cutting edge chip is provided with a two-edge cornering blade. Can do. In addition, since the outer peripheral edge originates from the 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 leading end portion where the cutting load is greatest. Furthermore, if it comprises a right-handed twisting blade with excellent machinability, the effect can be further enhanced. Further, by increasing the gash angle of the bottom blade to 30 to 45 °, it is possible to provide convenience for chip removal and further improve the machinability.
In addition, by maintaining an ungashed strip with a width of 0.1 to 1 mm parallel to the outer peripheral blade, the accuracy of the cutting blade is maintained and a uniform sharpness is ensured.
In addition, the value of the corner alarm can be changed only by exchanging with a cutting edge tip having a required value.
[0007]
【Example】
Hereinafter, the present invention will be described based on examples thereof.
FIG. 2 is a front view of a throw-away end mill according to the present invention. Reference numeral 1 denotes a holder body made of alloy steel, and a cutting edge tip 3 having a cutting edge at a tip protruding from the slit 2 at the tip. Is provided with a V-shaped slit 2 in the axial direction of the holder body 1 and a shank 4 with a diameter of 25 mm at the other end.
[0008]
As shown in FIGS. 3 to 5, the cutting edge tip 3 sandwiched between the V-shaped slits 2 has two outer peripheral blades 5 having a diameter of 20 mm created by the rotation of the tool, and the outer peripheral edge 5 is slightly different. A bottom blade 6 having a medium to low gradient but arranged almost vertically, and two corneral blades 7 having a radius of 5 mm, which are formed by an outer peripheral blade 5 and a substantially 1/4 arc in contact with the bottom blade 6, are provided. The axial length is 25 mm and the thickness is 5 mm.
[0009]
Since the outer peripheral blade 5 originates from the tip apex angle of the cutting edge tip 3 and extends in the axial direction, the tip thickness of 5 mm is responsible for the strength at the tip portion of the outer peripheral blade 5. In addition, a right twist blade with a twist angle α = 8 ° in the axial direction is formed.
The bottom blade 6 of the cutting edge tip 3 is provided with a gash angle θ at an angle of 35 °. However, since the bottom blade 6 is provided diagonally from the top vertex angle of the cutting edge tip 3, the strength due to the gash The decrease in is slight.
Moreover, the non-gash processed strip 8 is left on the outer peripheral blade 5 with a width of about 0.2 mm in parallel with the peripheral blade 5. In general, when a large gash angle θ is taken, a grinding streak remains on the outer peripheral edge during grinding with a grindstone, which impairs the cutting performance and shape accuracy of the cutting edge. Here, the accuracy could be maintained by leaving the ungashed portion as a strip.
[0010]
When the corner blade 7 having a radius of 4 mm or 6 mm is required for the cutting edge tip 2, the same tip size with only the corner value changed can be used. In comparison, it is economically advantageous.
When the throw-away end mill manufactured as described above was subjected to the contour die engraving of the die material, the intermittent cutting state was alleviated by the effect of the twisting blade, and good machinability was exhibited. Moreover, the chip could be cut with extremely high accuracy without any chipping.
[0011]
【The invention's effect】
According to the present invention, even for a relatively large diameter used for curved surface finishing such as shape transfer and three-dimensional profile cutting, the cutting edge strength and machinability are excellent, the machining accuracy is good, and the economy is excellent. A throw-away end mill equipped with a knurled ring could be obtained.
[Brief description of the drawings]
FIG. 1 is 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. 2;
FIG. 4 shows a side view of FIG.
FIG. 5 shows a top view of FIG. 3;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Holder body 2 Slit 3 Cutting edge tip 4 Shank 5 Outer peripheral edge 6 Bottom edge 7 Cornering edge 8 Ungashed strip θ Gash angle α Twist angle

Claims (2)

A slit extending in the axial direction is provided at the tip of the holder body, a tip having a cutting edge is sandwiched in the slit protruding from the slit, and an outer periphery in the axial direction is emitted from the apex angle of the tip to the cutting tip. blade and, the outer and peripheral edge peripheral cutting edge diagonally containing the axial center from the vertical angle emitted by the end cutting edge to substantially vertical position, the corner consisting of substantially quarter of a circle in contact with the peripheral cutting edge and end cutting edge in the bottom edge corner A throw-away end mill characterized by a pair of round blades.   The throwaway end mill according to claim 1, wherein the bottom blade has a gash angle of 30 to 45 °, and is configured to leave an ungashed strip in a width of 0.1 to 1 mm parallel to the outer peripheral blade. Characteristic throw-away end mill.

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