JPH1086014A - Throwaway tip with breaker for milling cutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a throwaway tip with a breaker groove for high precision, high efficiency processing of hard-to-cut materials such as stainless steel. SOLUTION: A rake face of a throwaway tip 1 used for milling cutter or the like is formed with a breaker groove 4 along a main cutting edge 2. Rake angle α formed with the breaker groove 4 is decreased gradually or in steps from the fore-end to the center of the main cutting edge 2. The sub-cutting edge portion 3 of the throwaway tip 1 is formed with a raised portion with its apex being lower than the ridge of the sub-cutting edge 3. The tip boss surface is located higher than the apex of a projection 5 and the ridge of the sub-cutting edge 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tip for use in a face mill or a throw-away type end mill, and more particularly to a tip which has a breaker on a rake face thereof.

[0002]

2. Description of the Related Art As a throw-away insert for a face mill or a throw-away type end mill, a breaker groove is formed on a rake face along a cutting edge ridge line of a chip rake face for the purpose of chip processing and reduction of cutting resistance. Some examples are shown in FIGS. 1 to 4. In the example of FIG. 1, the rake angle α can be provided as shown in the cross-sectional view of FIG. 2 by providing the breaker groove, and the chip upper surface (boss surface) is higher than the cutting edge ridge. 3 and 4
Is an example in which a rake angle is similarly provided, but the upper surface of the chip (boss surface) is lower than the cutting edge.

Provision of a projection in the groove of the breaker is performed to further reduce the cutting resistance as disclosed in Japanese Patent Application Laid-Open No. 8-39308. These milling throw-away inserts do not have a breaker, that is, they have a rake angle compared to a flat rake face, so they have low cutting resistance and good sharpness, so they are used in small output machines. It is used for machining of work materials without mounting rigidity.

[0004]

SUMMARY OF THE INVENTION For the purpose of high-precision, high-efficiency processing of difficult-to-cut materials such as stainless steel, that is, to extend the life of the insert and improve the precision of the finished surface, processing is performed by utilizing the goodness of the insert with a breaker groove. However, high accuracy and high efficiency processing could not be achieved with the conventional type. The reason for this is that materials that are easily work hardened, such as stainless steel, have large abnormal damage at the boundary of the used cutting edge. If there is a portion extending from the boss surface to the main cutting edge as shown in FIG. 1, chips are clogged during finishing (when the cutting depth is small). In the type shown in FIG. 2, since the boss surface is lower than the main cutting edge, the chips are stretched and hit the wedge member for fixing the chip, so that stable cutting cannot be performed.

[0005]

Therefore, in a throwaway insert having a clearance angle of 15 to 30 degrees used for a face mill or the like, a breaker groove is formed on a rake face of the throwaway tip along a main cutting edge. Along with
The rake angle formed by the breaker groove is reduced continuously or stepwise from the tip of the main cutting edge toward the vicinity of the center of the main cutting edge, and the rake angle is convex on the sub cutting edge portion of the indexable insert. A tip is formed, wherein a vertex of the convex portion is lower than a minor cutting edge ridge, and a tip boss surface is higher than a height of the minor cutting edge with respect to the projecting vertex. Further, the width of the breaker groove is defined by the spread angle r toward the center of the main cutting edge, and a concave portion may be formed near the center of the cutting edge, if necessary.

[0006]

When machining easily weldable materials such as stainless steel, a sharp cutting edge is required, and a large rake angle is required.
Use a throwaway tip. Then, FIG.
As shown in FIG. 9, a breaker groove 4 is formed on the rake face of the throw-away insert 1 along the main cutting edge 2 to give a large rake angle α1, and the rake angle α1 formed by the breaker groove 4 is set. The rake angle is reduced continuously or stepwise from the tip of the main cutting edge toward the vicinity of the center of the main cutting edge to make the rake angle α2, thereby increasing the strength of the boundary portion. In other words, a large rake angle is negative in terms of strength, and it is apt to cause chipping and chipping due to its sharpness. The strength of the cutting blade can be improved, and abnormal damage to the cutting blade can be prevented.

Further, since the boss surface is made higher than the main cutting edge 2, the wall rising from the breaker groove 4 to the boss surface serves as a protective wall 6 to prevent chips from contacting the wedge member.
By reducing the rake angle and widening the width of the breaker groove toward the center of the main cutting edge 2 with the divergence angle r, the flow of the chips becomes smooth, and the phenomenon that the rake angle α decreases and the cutting resistance increases increases. It is reduced by lowering the position where the debris breaks. Therefore, there is no particular problem if the spread angle is about 2 to 6 degrees. If the spread angle is too large, the breakage of the chips will not be effective, and if the spread angle is too small, the chips will be crowded.

[0010] Next, in order to prevent chips from being clogged with small incisions, the sub cutting edge 3 is provided with a projection 5 to stabilize the outflow of chips. As shown in FIG. 6, the protrusion 5 projects from the bottom of the breaker groove by 0.05 to 0.09 mm, but is arranged lower than the height of the sub cutting edge ridge so as not to hinder chip discharge. Further, in order to more smoothly discharge the chips in the vicinity of the boundary, the width of the breaker groove is slightly widened toward the center of the main cutting edge 2 at a spread angle r, as shown in FIG. Slowly launch the protective wall,
A recess 7 is formed near the center of the main cutting edge 2. The recess 7 is formed as follows.
Forming 5 to 2.5 mm rearward improves not only the chip dischargeability but also a good outflow of chips when the feed per blade is large and the depth of cut is deep. Also,
It is a feature of the present invention that the performance can be exhibited by both hands. Hereinafter, a detailed description will be given based on embodiments.

[0009]

[Embodiment] An inscribed circle φD =
12.7, height H = 3.18, clearance angle R = 20 °, positive 4
The rake angle of the breaker groove on the square tip is α1 = 20
And a combination of α2 = 15 ° was produced. Furthermore,
The sub cutting edge 3 was provided with a projection 5 and provided a rake angle similar to α2. The protrusion 5 is made 0.07 mm higher than the bottom of the breaker groove 4 in FIG.
= 4 degrees, the protective wall 6 is gently raised as shown in FIG. 9, a concave portion 7 is formed near the center of the main cutting edge 2, and the protective wall 6 is provided 2.3 mm rearward and the present invention is different from the present invention. did.
For comparison, the throw-away tip of FIG. 1 (rake angle 20 °) was similarly tested as a conventional product.

[0010] In consideration of the stability of the cutting edge in stainless steel cutting, insert grade is coated, and the test
US304 Milling speed V = 200 m / min with a milling cutter with a cutter diameter φ160, feed per tooth fz = 0.
15 (mm / blade), axial depth of cut d = 0.5, 1,
The test was performed under four conditions of 2, 3 (mm). Cutting depth d = 0.
In the case of 5 mm, normal cutting was possible in the example of the present invention and the finished surface was good, but the finished surface was deteriorated in the conventional product because chips were involved and chipping occurred. Cutting depth d = 1
mm, the cutting state was almost the same as 0.5 mm. When the depth of cut d was 2 mm, normal cutting was possible with both the present invention example and the conventional product, and normal wear was also exhibited at the boundary. Depth of cut d =
At 3 mm, in the example of the present invention, normal cutting was performed, and the vicinity of the concave portion 7 was a boundary portion, but normal wear was exhibited without chipping. In the conventional product, chipping occurred at the boundary and was lost at the beginning.

[0011]

As described above, by setting the angle of the breaker groove of the chip with a breaker groove for milling to 20 ° at the tip of the cutting blade and 15 ° near the center of the cutting blade, it is possible to process difficult-to-cut materials such as stainless steel. This is a chip with grooved groove for milling, which is most suitable for milling.

[Brief description of the drawings]

FIG. 1 is a top view of a conventional throw-away tip.

FIG. 2 shows a cross-sectional view of FIG.

FIG. 3 is a top view of another conventional indexable insert.

FIG. 4 shows a cross-sectional view of FIG.

FIG. 5 shows a top view of the throw-away tip of the example of the present invention.

FIG. 6 is an enlarged view of a main part of FIG. 5;

FIG. 7 is a sectional view taken along the line AA of FIG. 6;

FIG. 8 is a sectional view taken along the line BB of FIG. 6;

FIG. 9 is a sectional view taken along the line CC in FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Throw-away insert 2 Main cutting edge 3 Secondary cutting edge 4 Breaker groove 5 Projection 6 Protective wall 7 Concave l Difference between boss surface and cutting edge ridge r Spread angle α Rake angle

Claims (3)

[Claims] 1. A throw-away insert having a clearance angle of 15 to 30 degrees used for milling or the like, wherein a breaker groove is formed along a main cutting edge on a rake face of the throw-away insert, and the breaker groove is formed. Reduces the rake angle α continuously or stepwise from the tip of the main cutting edge toward the vicinity of the center of the main cutting edge, and the sub cutting edge portion of the indexable insert has a convex portion. Wherein the apex of the convex portion is lower than the minor cutting edge ridge, and the tip boss surface is located at a position higher than the height of the projecting vertex, the minor cutting edge ridge. Chips. 2. The indexable insert with a milling breaker according to claim 1, wherein the width of the breaker groove is defined by a divergence angle r near the center of the main cutting edge. Indexable tip. 3. The indexable insert with a breaker for milling according to claim 1, wherein a recess is provided near the center of the cutting edge.