JPS61121811A - Assembled cutting tool - Google Patents

Abstract

PURPOSE:To reduce the weight of an assembled cutting tool and enhance the accuracy of cutting and the quality of a cut surface, by making the body of the tool from a ceramic having a larger modulus of elasticity and a smaller specific gravity than steel. CONSTITUTION:A body 2 is made of an alumina ceramic by a strip-casting process and provided with grooves 5. The width of each groove 5 increases from its top toward its bottom. A blade 1 made of a very hard alloy and a wedge 3 are inserted in the groove 5 so that the blade is press-fitted on one side of the groove by the action of the wedge. Since the modulus of elasticity of the body 2 is high, the displacement of the cutting edge of the blade 1 is small and the accuracy of processing and the quality of a processed surface are high.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an assembly-type cutting tool in which a blade is fixed to a body, among cutting tools that are attached to a machine tool such as a milling machine or a boring machine.

[Conventional technology]

Assembled cutting tools are relatively large-diameter cutting tools, and have the advantage of being economical as they are made of high-quality tool material with good performance and are molded into the desired shape as a blade, which is then fixed to the body for ease of use. and is widely used.

Assembled cutting tools are widely used with blades made of cemented carbide, ceramics, or other tool materials.

On the other hand, as a material for the body, for example, JP-A-58-104
As seen in Publication No. 17, lI! system materials are used. Although cemented carbide is rarely used for cutting tools with simple shapes, it is most advantageous to use copper-based materials in consideration of ease of machining, material cost, cutting performance as a tool, etc.

For example, in the case of the body of a tool such as the assembly type end mill shown in Fig. 1, the blade 1 is placed in the groove 5 provided in the body 2 and fixed with a wedge 3, so as shown in Fig. 3(a).
As shown in FIG. 5, a screw hole 4C is provided for screwing in the head screw 4b for pressing the wedge 3 against the bottom side of the groove 5, or when the wedge 13 is driven in and fixed as shown in FIG. It is necessary to provide serrations 6 on the side surface having the slope and on the surface of the wedge 3 that contacts this side surface.

In such a case, the material for the body 2 must have good workability so that the screw holes 4c and the serration holes 6 can be easily formed, and also from the viewpoint of material strength to maintain tool performance. It is necessary to use the copper-based material,
[Problems to be Solved by the Invention] In recent years, the general trend in cutting has been toward high-precision cutting and high-speed, high-efficiency cutting. Although the 1ilPS material has excellent workability, it has a low rigidity value, so when it is used as a body material as described above, the upward cutting edge is displaced during cutting, and accurate cutting may not be achieved.

For example, in a survey using a commercially available end mill, the diameter was 10 m.
4 μm/kgf for m, 0 for 20 am
．． A displacement of 8 μm/kgf of the cutting edge occurs, which manifests as machining errors on the cut surface and deterioration of the roughness of the finished cut surface. Therefore, the displacement of the body cannot be ignored.

From the perspective of improving the sophistication of machining, it is desirable that the weight of the tool be light, and the larger the tool made of copper-based materials, the more
This has the disadvantage that the inertia loss when stopped is large.

An object of the present invention is to solve the above-mentioned problems and provide an assembly type cutting tool suitable for high-speed, high-precision cutting.

[Means for solving problems]

The present invention utilizes the material as a ceramic body material, which has a larger Young's modulus and a smaller specific gravity than W4-based materials.

Therefore, for the body ceramic, it is necessary to use a material that is strong and light in terms of both young modulus and specific gravity to withstand cutting force.

Table 1 shows a comparison of the characteristic values of typical ceramics and steel.

Alumina-based ceramics are suitable as materials with low density, high transverse rupture strength, and high Young's modulus.

tlS1 Table 2 [Example] FIG. 1 is a front view showing an example in which the present invention is applied to a prefabricated end mill having a diameter of 20#-, and ttS2 is an enlarged sectional view taken along line AA in FIG. 1.

In Figure 1.2, the body 2 is made of alumina ceramics by slip casting, and has an axis near the right end and an appropriate helix angle, and a groove with a width larger on the bottom side than on the opening side. 5 is provided. A blade 1 made of cemented carbide (indicated by dotted diagonal lines in FIG. 1) is inserted into this groove 5 and is in contact with one side wall of the groove 5, and a cross section of the groove 5 on the other side. A wedge 3 having a cross-sectional shape corresponding to the shape is inserted.

That is, the width of the wedge 3 on the back side near the bottom of the groove 5 is larger than the width on the outer surface side. Therefore,
As it moves outward, a wedge action forces the blade 1 into the groove 5.
It is fixed by crimping it to one side wall of the. In order to move the wedge 3 outward, the set screw 4 may be inserted into the thread 4a provided in the wedge 3 and tightened toward the bottom of the groove 5.

Therefore, since there is no need to machine a screw hole in the bottom surface of the groove 5 of the body 2, the body 2 can be easily manufactured from ceramics.

The wedge 3 can be moved outward by using a set screw as described above, or by other methods.

In the above example, the tool weight could be reduced by about 50%.

Additionally, cutting tests showed that machining errors on the finished surface due to tool rigidity were improved to a negligible degree, and errors caused by spindle play and cutting edge helix angle were suppressed to slight errors.

When the present invention is applied to an assembled end mill with a diameter of 50 mm, the accuracy improvement due to improved rigidity is
Although it was not as noticeable in the case of the 0-1 tool, the weight of the tool was reduced to 2, from about 1 kg to about 50%, and
Take it to the machine! It has become extremely easy to handle when attaching coins, and the efficiency and safety of counterfeit coins have been significantly improved.

〔Effect of the invention〕

The present invention has the following numerous effects.

(1) Compared to conventional bodies, the displacement of the cutting edge during cutting can be kept low due to the improved Young's modulus, making it possible to obtain high-quality machined surfaces with good cutting accuracy and small surface roughness. .

(2) Since the density is low, the main wheel can be started, stopped, or accelerated/decelerated smoothly, making it suitable for high-speed cutting.

(3) The weight of the tool is reduced, making it easy to handle even large tools, contributing to improved work efficiency and safety.

(4) The body can be manufactured easily by applying the slip casting method.

(5) Can be widely applied not only to end mills, but also to front cutters, side cutters, drills, reamers, etc.

[Brief explanation of drawings]

FIG. 1 is a front view showing one embodiment of the present invention, and FIG. 2 is a front view showing one embodiment of the present invention.
FIG. 3(a) is an enlarged sectional view taken along the line A-A in the figure. (b) is a sectional view of a main part showing a conventional example of a fixing structure between a body and a blade. 1 Niblade, 2: Body, 3: Wedge, 4
: Set screw, 5 : Mizo agent Patent attorney Takashi Honma Figure 1 Figure 2 Figure 3

Claims (3)

[Claims] (1) An assembly type cutting tool comprising a plurality of blades fixed to the tip of a body, characterized in that the body is made of ceramics. (2) Provide a groove near the tip of the body that has an appropriate helix angle with the axis of the body and is wider on the bottom side than on the opening side, and insert the blade and wedge into this groove. 2. The assembly-type cutting tool according to claim 1, wherein the cutting tool is inserted into the groove and the blade is pressed against the side wall of the groove via a wedge. (3) The assembly type cutting tool according to claim 1 or 2, wherein the body is made of alumina ceramics.