JP2526707Y2 - Rotary cutting tool - Google Patents

Description

[Detailed description of the invention]

[0001]

INVENTION The present invention relates to a mill which coordinated the helical teeth of the hard sintered body mainly composed of diamond and cubic boron nitride (CBN) and the like, relates to a rotary cutting tool of the reamer or the like.

[0002]

2. Description of the Related Art Hard sintered bodies such as diamond and CBN have very high hardness and are therefore frequently used as cutting edges for processing non-ferrous metals such as aluminum alloys and for processing hardened steel and cast iron.

Conventionally, a hard sintered body for a cutting blade is made of a flat material by a hard sintered body layer of diamond, CBN or the like and a cemented carbide base material layer integrally formed by simultaneous sintering. Carbide is formed on the bearing surface provided on the tool body.
The base layer of the alloy is fixed by brazing.

[0004] However, such a flat hard sintered body is attached as it is along the axis of the tool body,
When used as a cutting edge of a rotary tool such as an end mill or a reamer, the shape of the hard sintered body restricts the shape of the cutting edge, making it difficult to design a sharp tool.

That is, in the case of a rotary tool such as an end mill or a reamer , it is required that a cutting edge be twisted to have a large rake angle in order to enhance sharpness. Mounting along the axis,
Alternatively, in a structure in which the cutting blade is mounted with a slight inclination, a large rake angle cannot be formed on the cutting blade, and the sharpness cannot be significantly improved.

For this reason, a conventional rotary tool using a hard sintered body as a cutting blade has a large cutting resistance and tends to generate chatter. Further, since the rake angle is small, it is difficult to discharge chips. Not good.

Accordingly, the present applicant has proposed a tool effective for solving the above-mentioned problem in Japanese Utility Model Application No. 2-102789. In this tool, as shown in FIGS. 3 and 4, a flat bearing surface 13 inclined at an angle close to the lead angle of the torsion blade is provided on the outer periphery of the tool body 1, and a hard sintered body layer is provided on the bearing surface. 5
In which the cutting edge tip 4 a cemented carbide substrate layer 6 made of cemented carbide alloy substrate layer 6 which for supporting brazing so as to be positioned in the rotational direction behind the twisted blades 7 and.

[0008]

In the above-mentioned rotary cutting tool proposed by the present applicant, the design of the twisting blade is regulated by the thickness of the hard sintered body layer 5, and in addition, the starting edge A to the ending B of the cutting edge.
Toward the, drops retention of the chip brazing area of carbide alloy substrate layer 6 is decreased, therefore, the rotation angle (effective helix angle) of the cutting edge in the front view of figure 4 alpha a too large Therefore, in the case of a tool having a long blade length, the lead angle of the torsion blade that determines the axial rake must be reduced, and the effect of improving sharpness and preventing chatter becomes insufficient. was there.

It is an object of the present invention to solve this problem and to make it possible to increase the lead angle of the twist blade while keeping the radial rake constant.

[0010]

According to the present invention, in order to solve the above-mentioned problems, a straight seat groove is provided on the outer periphery of a tool body, which is inclined at an angle approximating a required lead angle of a torsion blade. , the brazed a cutting blade tip where the hard sintered body layers <br/> integrally laminated on one surface of the cemented carbide base material layer, the cutting blade chip
Rotary cutting machine in which the twisted blade is formed by a hard sintered body layer
Tool, the cemented carbide base material layer of the cutting edge
The sintered layer has a harder sintered body layer than the cemented carbide base material layer.
It is arranged to be located in the rear in the rotation direction, and the twist blade is
It can be formed over the entire width of the hard sintered body layer thickness
It is.

[0011]

Since the seat groove is inclined at an angle approximating the lead angle of the cutting edge and the cutting edge tip is fixed thereto, a twisted blade can be formed by using a flat-shaped tip having a regulated size. .

Further, since the arranged hard sintered layer of the chip in the rotational direction behind the tool than cemented carbide base <br/> material layer, the helical teeth over the entire width of the thickness of the hard sintered body layers can be formed Tona
You. Further, without even soldering area of carbide alloy substrate layer is extremely reduced toward the starting end side of the cutting edge on the end side, which
Thus, the effective twist angle α can be increased to increase the lead angle.

Hereinafter, the design restrictions of the twist blade will be described in more detail. If the radial rake of the torsion blade is made to be substantially constant at each part of the cutting blade, the direction of the rake face 8 gradually rotates by the same angle as the angle α from point A to point B in FIG. However, Figure 3, if it is 4 configuration, gradually carbide position twisted blade 7 by the rotation
Since it is biased toward the alloy base material layer 6 side, the end B must be determined before the twist blade 7 reaches the cemented carbide base material layer 6 in order to form a cutting edge of a hard sintered body, and it can be set. The lead angle (axial rake) becomes smaller. In contrast,
The configuration of the present invention, the cemented carbide substrate layer and the hard sintered layer
Since the positional relationship is opposite to that of FIGS.
As shown in FIGS. 1 and 2, a twist blade provided on the hard sintered body layer 5
7 is arranged near the boundary with the cemented carbide base material layer 6,
From there, move the cutting edge to the end of the hard sintered body.
Transition from the tool radial outer surface of layer 5 to the tool rotating direction rear surface
Can be done. In addition, with this shift, twisted blade
At the end side of 7, the cutting load is mainly applied to the cutting edge tip 4.
To be added in the width direction of the chip.
It is possible to secure the required strength of the cutting edge by reducing the width of layer 5
become. Thereby, the effective torsion angle α is increased until the radial lake is substantially constant and the width W ₁ (see FIG. 2) of the hard sintered body layer 5 is reduced to the minimum necessary size .
Yet, can it to be sufficient brazing area.

[0014]

1 and 2 show an example of a rotary cutting tool according to the present invention. As shown in the figure, the engineering tool main body 1, and Zamizo 3 extending linearly inclined toward the axial direction, this Zamizo 3
Is formed along the chip pocket 2 . The inclination angle of the seat groove 3, along the helical teeth 7 cutting inserts 4, which is secured thereto, is set to an angle that approximates the lead angle of the helical teeth.

The cutting tip 4 is made of diamond or CBN.
A hard sintered body layer 5 made of cemented carbide alloy substrate layer for supporting lifting 6
It is formed by integral molding by co-sintering the hard ware
It housed in the seat grooves 3 in the direction in which sintered body layer 5 is located towards after rotation direction of the tool than the cemented carbide base material layer 6, brazing a cemented carbide substrate layer 6 in the groove surface of Zamizo 3 And attached to the main body 1 . The cutting blade tip 4, used as the prismatic elongated objects or outer surface is curved in a form close to the final shape, the main body 1
After the brazing to the blade, unnecessary portions are removed by performing a cutting process, and a twisting blade 7 having a constant lead angle and a rake face 8 are provided. The rake face 8 extends from the starting end A of the twisting blade 7 to the end B
From the front of the hard sintered body layer 5 in the tool rotation direction
The position shifts to the radially outer surface, and during that time, the rotation is substantially α, so that the radial rake is substantially constant at each part of the cutting blade. The rake face 8 is usually the chip pocket 2
Processed at the same time, but before brazing the cutting tip 4
The processed switching chips pockets 2, the cutting edge after the chip brazing
There is also a method of processing only.

With such a structure, the effective twist angle α
The cutting edge can be attached to the hard sintered body layer 5 even if the diameter is increased, and the radial rake at each part of the twisted blade 7 can be made uniform as in the embodiment.

According to the calculation results, in the conventional structure shown in FIGS. 3 and 4, in the case of a tool having a blade length of 2.5D (D = tool diameter), the effective torsion angle α that can be employed is the rigidity of the tool body 1, the cutting edge tip. 50 ° is the limit in view of the holding power of the cutting edge, the strength of the cutting blade at the end of the twisting blade, the life, and the like. Therefore, the upper limit of the lead angle of the twisting blade is 10 °.

On the other hand, in the structure of the present invention, in the case of tools having the same blade length, the effective torsion angle α can be increased to 100 °, and the upper limit of the lead angle is doubled to 20 °.

The results of the cutting performance test using the prototype tool are described below. 1mm thick on end mill with outer diameter D = 13mm
A cutting edge having a hard sintered body (CBN) was brazed, and a twisted blade having a blade length of 35 mm was formed on the tip with a lead angle of 15 ° to complete the tool of the present invention. The cutting performance was compared with this and an end mill with a lead angle of 8 ° according to the conventional structure shown in FIGS.

The gray cast iron FC25 is rotated at a rotational speed of 5000 rpm.
m, axial cut 30 mm, radial cut 0.1 mm
When the finished surface roughness when the side surface was machined under the conditions of the above was examined, Rmax 1.6 μm was obtained with the tool of the present invention,
In the case of the conventional tool, Rmax was 4.1 μm. From this result, it can be clearly understood that the tool of the present invention performed stable cutting with small vibration.

[0021]

As described above, the cutting tool according to the present invention has a simple method in which the mounting direction of the cutting tip in the straight seat groove is reversed from that proposed in Japanese Utility Model Application No. 2-102789. In this way, it is possible to increase the lead angle of the twist blade by keeping the radial rake constant, so the sharpness and chip discharge performance are further improved,
The effect of being more advantageous in terms of high precision processing and high efficiency processing can be obtained.

[Brief description of the drawings]

FIG. 1 is a side view of an embodiment of the present invention.

FIG. 2 is an enlarged front view of the tool of FIG. 1;

FIG. 3 is a side view of a conventional tool.

FIG. 4 is an enlarged front view of the tool of FIG. 3;

[Explanation of symbols]

1 tool body 2 chip pocket 3 Zamizo 4 cutting inserts 5 hard sintered layer 6 terminating α effective helix angle 13 seating surface of the leading end B helical teeth carbide alloy substrate layer 7 twisted blade 8 rake face A twisted blade

Claims (1)

(57) [Scope of request for utility model registration] 1. A provided a straight Zamizo inclined at an angle approximating the lead angle of the required helical teeth on the outer periphery of the tool body, its seating groove, a hard sintered body layers on one surface of the cemented carbide base material layer <br/> The brazing of the cutting edge chip which was laminated and integrated into a flat plate
In a rotary cutting tool having the twisted blade formed of a hard sintered body layer of a cutting edge tip, a cemented carbide base material layer of the cutting edge tip is provided.
And the hard sintered body layer, and the hard sintered body layer is
Also, position it so that it is located in the rear of the tool rotation direction.
Knurled blades can be formed over the entire width of the hard sintered body layer
Rotary cutting tool, characterized in that the the.