JPS63306806A - Throw-away chip - Google Patents

Abstract

PURPOSE:To prevent chipping due to collision of cutting chips without promoting abrasion due to lowering of sharpness by increasing bevelling amount at cutting portion of chip formed from super hard coated alloy or thermet only at a portion where cutting chips collide during cutting work. CONSTITUTION:At a portion where the distance l from a joint (a) between a curved cutter 1 at nose section and a linear cutter 2 is longer than 14% of the entire length L of the linear cutter 2, the width of bevelling C1 is made wider than the width of other bevelling C2. Under practical cutting condition, the curved cutter 1 and the portion where the distance l is shorter than 14% of the entire length L are utilized effectively for cutting, and even if cutting is made instantaneously with a portion where l exceeds over 14% of the entire length L, it causes no bad influence. When bevelling C1 has the width X wider than 0.10mm at the cutting face side 3 and the width of 0.035mm at the flank side while the bevelling C2 has the width Z at the cutting face 3 side in the range of 0.02-0.10mm, sharpness degrading and abrasion are not promoted.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an indexable insert made of coated cemented carbide or cermet used for cutting steel, castings, etc. This invention relates to a throw-away insert that prevents breakage due to chips without reducing wear resistance.

[Conventional technology and its problems]

Cemented carbide, coated cemented carbide, or cermet has advantages such as high hardness of 4 and resistance to high-speed cutting. In particular, coated cemented carbide or cermet is suitable for high-speed cutting and is already becoming the mainstream for indexable inserts.

Now, just like other cutting tools, indexable inserts made of coated cemented carbide or cermet should also be compatible with the recent remarkable increase in cutting speed (tool materials tend to become even harder). .

On the other hand, as cutting speeds increase, it has become difficult to cut chips using the well-known chip breaker, especially in the case of tough workpiece materials, and as a result, the chips produced are elongated and the cutting chips are left unused. Situations such as being hit by a knife often occur.

However, coated cemented carbide chips (hereinafter referred to as
This is called a coated chip) or a cermet chip, which has improved wear resistance for high-speed cutting and is also becoming more brittle, so collisions with chips can chip the unused blade and cause damage to the main parts. Then, I am faced with the problem.

In addition, for coated chips or cermet chips,
To ensure the strength of the cutting edge, the entire cutting edge is usually made with a width of 0.
．． A fairly uniform round honing or chamfering process is performed at a certain width ranging from 0.2 m to 0.1 m, but simply increasing the amount of chamfering on the entire cutting edge will result in damage due to collision of chips. Even if this can be prevented, there is a problem in that it is not possible to suppress a decrease in durability (wear resistance) due to a decrease in cutting quality due to chamfering.

This invention aims to eliminate such problems.

[Means for solving problems]

This invention attempts to solve the above-mentioned problems by increasing the amount of chamfering on the cutting edge only in the area where chips collide with each other during cutting.

In other words, the generated chips hardly collide with the cutting edges near the corners that are involved in cutting, as well as the effective cutting edges that are outside the cutting area, and are scattered between the nose parts that are not used for cutting. The collisions are concentrated in the middle part of the side (hereinafter referred to as the center part of the side).

Therefore, the inventors thought that chipping due to collision of chips could be prevented by increasing the chamfer width only at the center of the side, and conducted various studies.

As a result, as shown in Fig. 1, the curved cutting edge 1 of the nose part
The distance l from the contact point a of the straight cutting blade 2 is 14% of the total length (length from the contact point to the other end side contact point) L
Chamfering CI attached to the straight cutting edge in the part separated by more than
It is effective to make the width of the chamfer C8 larger than the width of the chamfer C8 attached to the other cutting edge parts. If E is less than 14% of the straight cutting edge part, cutting performance will deteriorate (cutting quality will deteriorate and wear will occur). It turns out that it becomes easier.

This means that under practical cutting conditions, the curved cutting edge 1 and the portion of the straight cutting edge 2 where the separation distance l from the contact point a is less than 14% of L are effectively used for cutting; Furthermore, even if cutting is performed in a part that momentarily exceeds 14% during copy cutting, etc., the damage to the overcut part is extremely small and is estimated to have no effect on the effective life of the cutting edge. Ru.

In addition, the chamfer width of C2 is such that the width X on the rake face 3 side is 0.1
Less than 0w, width Y on flank 4 side shown in Figure 2 is 0.035
It was also found that there is no effect at less than m.

Furthermore, if the width Z of the chamfer cl of the blade part on the side used for cutting is less than 0.02fi on the rake face 3 side, the strength of the cutting edge will be insufficient and chipping will easily occur during cutting; 0.
1 (It was found that when the length exceeds 1 m, the strength of the cutting edge increases, but the sharpness of the cutting edge decreases and wear progresses faster.

In this invention, the chamfer widths of CI and Cz are not only differentiated, but also their sizes are limited for the above reason.

[Example 1] Chips No. 1 to Na8 (only tlh8 is a product of the present invention and the others are comparative products) having the shape shown in the attached drawing and the dimensions of each part as shown in Table 1 were prepared, and were tested under the conditions shown in Table 2. , diameter 200, thickness 2
The end face of a 0 m disc-shaped work material S CM420 was machined. The results are also shown in Table 1.

The indexable tip used is model number 130.
CNMG 120408, and the material is P05.
Cemented carbide equivalent to the grade is coated with TiC of thickness I,
Furthermore, the outer periphery is coated with Al2O with a thickness of 4 μm.

Table 1 Table 2 [Example 2] The dimensions are the same as in Example 1, the chip model number is the same ISO CNMG 120408, and the material is a round 9 chip made of cermet equivalent to PIO grade.
~&16 (only lb16 is a product of the present invention and the others are comparative products) were prepared, and end face processing of a disc-shaped workpiece having the same dimensions and material as in Example 1 was performed under the conditions shown in Table 3. Table 4 shows the results.
Shown below.

Table 3 Table 4 From the results of the above examples, it can be seen that the coated tip or cermet tip of the present invention can prevent chipping due to chips without increasing the amount of wear on the flank surface (without reducing the cutting quality). I understand.

〔effect〕

As described above, this invention changes the width of the chamfer from the middle and skillfully adjusts the distance to the point of change and the chamfer width, thereby eliminating chips without accelerating wear due to deterioration of cutting quality. Since chip breakage caused by collision is prevented, it is possible to exhibit highly reliable breakage resistance that can sufficiently cope with further hardening of coated cemented carbide chips or cermet chips, and it is possible to prevent cutting. This has the effect of contributing to further speeding up.

[Brief explanation of the drawing]

FIG. 1 is a plan view of essential parts showing an example of a coated cemented carbide chip or a cermet chip according to the present invention, and FIG. 2 is a side view of the same. 1... Curved cutting edge, 2... Straight cutting edge, 3
・・・・・・Su (I side, 4... Flank side, C,,
Ct: chamfer, L: total length of the straight cutting edge, 2: separation distance of C1 from the point of contact between the curved cutting edge and the direct cutting edge. Patent applicant Sumitomo Electric Industries, Ltd. Agent Kama 1) Text 2 Figure 1 Figure 2-

Claims (1)

[Claims] An indexable insert made of coated cemented carbide or cermet, which performs straight cutting at a portion where the distance from the contact point of the straight cutting edge to the curved cutting edge of the nose section is 14% or more of the length of the straight cutting edge. The width of the chamfer C_1 attached to the blade part is larger than the width of the chamfer C_2 attached to the other cutting edge parts, and the chamfer width of the above C_1 is 0.10 mm or more on the rake face side and 0.1 mm or more on the flank side. .035mm or more,
On the other hand, the chamfer width of C_2 is 0.02mm on the rake face side.
A throw-away tip characterized in that each of the above is set within 0.10 mm.