JPH0810482Y2 - Ball end mill structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The disclosed technology belongs to the technical field of the structure of a ball end mill used for molding of a die made of a difficult-to-process material.

<Summary of summary> Thus, the present invention is a device relating to the structure of a ball end mill used for molding of a die made of a difficult-to-process material having CBN or diamond as a main component and a cutting edge formed on the shank tip. , In particular, the cutting edge portion integrally formed on the tip portion of the shank portion is formed into a linear cutting edge portion similar to the round portion of the shank tip portion in a front view, and is integrated with the cutting edge portion. To continuously form an outer peripheral cutting edge having a diameter larger than that of the rounded portion, and a neck cutting edge is continuously formed integrally with the outer peripheral cutting edge in a shank portion and a portion having a diameter smaller than the outer diameter of the rounded portion. The ball in the conventional form is formed in a steep slope on the ring-shaped step portion, and the cutting edge length of the rounded cutting edge and the outer peripheral cutting edge is substantially the same as the radius of the outer cutting edge in the vertical length in side view. Formed shorter than the cutting edge length of the end mill The invention is related to the ball end mill structure.

<Prior Art> As is well known to those skilled in the art, a ball end mill is widely used for forming a mold having a complicated curved surface in the automobile manufacturing industry, the electrical equipment manufacturing industry, and the like.

As such a ball end mill, a ball end mill 1 made of high speed steel or cemented carbide as shown in FIG. 5 is used, and a rounded cutting edge 2 and an outer peripheral cutting edge 3 integrally continuous with the rounded cutting edge 2 are provided on the outer peripheral cutting edge 3 part. It was used by being formed into a cutting edge significantly longer than the diameter of the.

As a result, the number of dies used as the target work is increased by carburizing and nitriding as a measure to improve the life of the dies, and those made of difficult-to-process materials such as graphite are used.
Therefore, the ball end mill 1'having a rounded cutting edge 2'and a peripheral cutting edge 3'made of a hard sintered body containing diamond or CBN as a main component as shown in FIG. , The reduction of machining efficiency by the ball end mill 1 made of high speed steel or cemented carbide has been covered.

<Problems to be solved by the invention> However, a ball end mill 1'having cutting edges 2 ', 3 made of a hard sintered body containing diamond or CBN as a main component is extremely expensive in terms of the material used. As shown in FIGS. 6 and 7, the cutting edge length H of the round end cutting edge 2'of the ball end mill 1'and the outer peripheral cutting edge 3'with respect to the cutting direction f is the cutting allowance d. Compared to this, the machining cost is high, and it is difficult to secure precision due to difficult cutting. On the other hand, shortening the cutting edge limits the field of use. was there.

Thus, in the mold forming process, the draft α is generally
However, even though the cutting allowance d is short, the ball end mill 1'has the disadvantage that the manufacturing cost of the ball end mill 1'is extremely high because of the long peripheral cutting edge 3 '.

<Purpose of the Invention> The purpose of the present invention is to solve the problems of the ball end mill having a long cutting edge used in the molding and the like of the mold based on the above-mentioned conventional technique, and to solve the problem, a hard sintered body used for the cutting edge. The ball end mill structure that reduces the cost by reducing the amount of metal, improves the tool rigidity, has many uses, and has good re-polishing, and is useful in the field of machining technology application in the machine manufacturing industry. It is intended to be provided.

<Means and Actions for Solving the Problem> In order to solve the above-mentioned problems, the structure of the present invention, which is based on the above-mentioned purpose, is summarized as follows. When performing a die cutting process or the like with a ball end mill, to integrally form a cutting edge made of a hard sintered body containing diamond or CBN as a main component in the rounded portion of the tip portion of the shank portion of the ball end mill, A rounded cutting edge that is linear in a front view is formed in a similar manner to the rounded portion, and an outer peripheral cutting edge is continuously formed on the outer diameter portion of the rounded cutting edge in a side view vertical length with the rounded cutting edge. Is formed to have substantially the same length as the radius, and therefore, the ring-shaped step portion of the shank portion and the rounded portion is continuously steeply continuous with the outer peripheral cutting edge and is steeply integrated with the outer peripheral cutting edge stepwise. The neck cutting edge of the is formed with a steep inclination, and the side view of the cutting edge The length is remarkably shorter than that of the conventional one, so the amount of hard sintered body used is small, the cost can be reduced, the rigidity of the tool is improved, and the re-polishing property of the outer peripheral cutting edge is also improved. However, the cutting uses such as finishing have increased, and the technical measures have been taken so that a sufficient cutting allowance can be obtained.

<Embodiment> Next, one embodiment of the present invention will be described below with reference to FIGS.

It should be noted that parts that are the same as those in FIG. 5 and subsequent figures will be described using the same symbols.

1 "is a ball end mill that forms the center of the invention, and a shank portion 4 has a tip end portion made of a hard sintered body having a CBN or diamond as a main component, and a round portion cutting edge 2".
Is integrally formed in a straight line when viewed from the front, and an outer peripheral cutting edge 3 ″ is formed integrally with the base of the rounded edge cutting edge 2 ″ so as to be continuous with the outer diameter of the cutting edge 2 ″. The ring-shaped step portion 5 between the outer peripheral cutting edge 3 ″ and the shank portion 4 has a diameter of 0.5 to 1 mm smaller than the radius of the radius cutting edge 2 ″, and the neck cutting edge 6 is steeply inclined. It is formed integrally and continuously.

The vertical lengths of the rounded cutting edge 2 "and the outer peripheral cutting edge 3" are H'when viewed from the side, and as shown in FIG. 4, they are approximately the same length as the radius of the outer peripheral cutting edge 3 ". It is made sufficiently shorter than that of the conventional mode shown in FIG. 7, and the cutting allowance d'is about 0.5 mm, as compared with the conventional cutting allowance d for the mold as the work of the ball end mill 1 ', and , The draft α'can be taken sufficiently.

The outer peripheral cutting edge 3 "is designed to be sufficiently re-polished.

In the above configuration, when the side surface grinding of the mold as the work is performed by the ball end mill 1 ″, even if the sufficient draft angle α ′ is provided as usual, the rounded edge 2 ″ and the outer edge 3 ″ are provided. With this, the side surface can be sufficiently grounded, and the cutting allowance d'is sufficiently 0.5 mm.

During this time, the vertical length H ′ of the cutting edges 2 ″, 3 ″ in the side view is considerably shorter than H of the conventional embodiment of FIG. 7, so that sufficient tool rigidity is obtained and vibrations etc. do not occur. Further, the durability is sufficiently ensured, and a variety of applications such as finish processing can be sufficiently obtained.

The embodiment of the present invention is not limited to the above-mentioned embodiment, and various embodiments such as freely setting the twist angle can be adopted.

<Effect of the Invention> As described above, according to the present invention, in a ball end mill used for forming a surface of a workpiece such as a die made of a difficult-to-machine material having a complicated side surface, the cutting edge is made of CBN or diamond. It is formed of a hard sintered body as a main component, and further, the front end portion of the shank portion has a linear rounded cutting edge and a peripheral cutting edge continuous with the rounded cutting edge, which is approximately the diameter of the peripheral cutting edge. By shortening the length to the same length and forming the neck cutting edge integrally with the ring-shaped step portion between the shank and the shank portion, not only the function of the outer peripheral cutting edge can be substantially retained, but also extremely expensive. It has an excellent effect that the amount of hard sintered body containing CBN or diamond as a main component is small and the cost reduction can be promoted.

Also, since the outer peripheral cutting edge is shorter than the conventional length in a side view together with the rounded cutting edge due to the formation of the neck cutting edge,
Even when the tool has increased rigidity and the work is drafted, the cutting edge can be long enough to withstand a small amount of cutting allowance, and it is used for many finishing applications. This has the effect of increasing the degree of freedom.

Further, since the outer peripheral cutting edge is short, there is also an advantage that re-polishing can be freely performed.

[Brief description of drawings]

1 to 4 are explanatory views of an embodiment of the present invention. FIG. 1 is an overall schematic side view, FIG. 2 is an enlarged side view of a cross section of a tip portion thereof, FIG. 3 is a front view, and FIG. Is a side view of a partial cross section of a grinding process, FIG. 5 is a side view of a ball end mill based on the prior art, FIG. 6 is an enlarged side view of a cross section of the tip part, and FIG. 2 ″, 3 ″, 6 …… Cutting edge, 2 ′ …… Rounded edge cutting edge 3 ′ …… Outer peripheral cutting edge, 6 …… Neck cutting edge 1 ′ …… Ball end mill, 4 …… Shank part 5… Step Department

Claims (1)

[Scope of utility model registration request] 1. In a ball end mill structure in which a shank tip cutting edge is formed of a hard sintered body containing CBN or diamond as a main component, a straight rounded cutting edge in front view is provided at the tip. And the outer peripheral cutting edge has a vertical length which is substantially the same as the radius in a side view and has an outer peripheral cutting edge that is continuous with the rounded cutting edge in the outer shape portion that follows this, and a neck that is continuous with the rear portion of the outer peripheral cutting edge. A ball end mill structure characterized in that a cutting edge is formed steeply on a ring-shaped step portion formed on a shank portion and a portion having a diameter smaller than the outer diameter of the round portion.