JPH081065U - Tool holder - Google Patents

Abstract

(57) [Summary] [Objective] The present invention absorbs vibrations by using toughness spheroidal graphite cast iron for parts of the holder body, supporters, etc., improves vibration damping action, and enables highly efficient cutting. The purpose is to provide a tool. [Structure] The holder of the present invention absorbs vibration in the part where spheroidal graphite cast iron is applied, and makes the ratio of logarithmic attenuation rate 2 to 4%, which enables smooth and quiet cutting, and reduces vibration and chipping. , A better cutting surface can be obtained and the chip life can be extended. In addition, it can be used under cutting conditions equivalent to or better than conventional ones, improving efficiency.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention relates to improvement of a holder used for cutting of a lathe, and is characterized in that the holder has both vibration absorption and high rigidity.

[0002]

[Prior art]

 In the past, various methods have been pointed out for processing vibration, noise, and cut chips in the cutting work using a lathe. In particular, vibration is an important factor in the performance of the tool, maintenance of the machine body, etc., so measures against vibration are made by adjusting the rigidity of the machine body, tool attachment, tool body, etc., and the specifications such as cutting speed. I've been told. Although various measures can be considered to reduce these vibrations and noises, the symptoms are extremely diverse and complicated.

Further, when performing heavy cutting / intermittent cutting, both vibration and noise are increased, the machine body is also large, and the present situation is that the cutting specifications are loose. Moreover, dimensional accuracy is required to some extent even in rough machining. This tendency is remarkable especially when a coated tool is used. Although the surface roughness of coating tools is not very good, heavy interrupted cutting can be performed at high speeds, so it is necessary to devise a method that ensures intermediate finishing accuracy.

[0004]

[Problems to be solved by the device]

 The present invention has been made in view of such circumstances, and uses a vibration-damping material that absorbs vibration in the cutting tool body and maintains the rigidity of the cutting tool body. It is clear that it is not preferable from the viewpoint of rigidity when the entire bite holder is made of a material that is excellent in vibration absorption, and a throw-away bite holder that improves the above-mentioned drawbacks of the conventional bite holder is provided. The purpose is to do.

[0005]

[Means and Actions for Solving the Problems]

After the holder is forcibly vibrated by an external force and the external force is suddenly cut off, the logarithmic attenuation rate is calculated from the following formula from the time change of the amplitude magnitude when the vibration of the sample piece attenuates. Logarithmic decay rate = 1 na _i / a _{i + 1} a _i : magnitude of i-th amplitude The result is schematically shown in FIG. In FIG. 1, the vertical axis represents the magnitude of the function of damping the vibration by an amount called logarithmic damping rate, and the horizontal axis represents the Young's modulus, which is the rigidity of the material. This represents the magnitude of the stress required to cause a unit amount of relative strain. FIG. 1 is based on numerical values for the bending primary vibration of the holder for both parameters. Next, Fig. 2 shows a simple representation of logarithmic decrement-stiffness. From the figure, the material shows a rough distribution from the upper left to the lower right. Those having a low vibration damping capacity, on the other hand, those having a large damping rate such as rubber have a low rigidity and are soft.

As shown in FIG. 1, it is preferable that the holder has a high Young's modulus and a large logarithmic damping rate. For example, if cemented carbide is used for the holder, the rigidity is improved, but the damping is increased. It can be said that the rate is close to 0 and is not suitable for cutting with severe vibration. In addition, the vibration-isolating material that is a combination of steel and resin, which is generally used, has low rigidity, indicating that it is difficult to apply it to the holder by itself. Hereinafter, detailed description will be given based on examples.

[0007]

【Example】

 FIG. 3 shows a bite holder, and FIG. 4 shows a front milling cutter. As the material for the main body 1 or 2, the supporter 3, and the wedge portion 4, conventional Cr-Mo steel is applied instead of tough spheroidal graphite cast iron. Further, the present invention product and the conventional product were compared in the cutting of carbon steel by the throw away tool shown in FIG. The results are shown in FIG. 5. While the surface roughness of the conventional product deteriorated due to chipping, the product of the present invention showed no chipping and a good cutting surface was obtained. Furthermore, by applying the spheroidal graphite cast iron, there is an effect that the use of the spheroidal graphite cast iron can be easily molded and the material and the processing cost can be reduced.

[0008]

[Effect of device]

 As described above, according to the present invention, even in a machine having low rigidity, vibration can be absorbed in a portion to which spheroidal graphite cast iron having a logarithmic damping ratio of 2 to 4% is applied, and smooth and quiet cutting can be performed. Reduced vibration and chipping results in better cutting surfaces and longer tip life. In addition, it can be used under cutting conditions equivalent to or better than conventional ones, improving efficiency. Furthermore, the reduction of vibration due to cutting leads to stable machine precision and does not adversely affect other machines around.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a logarithmic decay rate.

FIG. 2 is a diagram for explaining the relationship between logarithmic decrement and rigidity.

FIG. 3 is a side view of an application example of the present invention.

FIG. 4 is a side view of another application example of the present invention.

FIG. 5 is an explanatory diagram showing a comparison result between a throw-away type cutting tool to which the present invention is applied and a conventional throw-away type cutting tool.

[Explanation of symbols]

 1 Bit holder 2 Front milling cutter 3 Supporter 4 Wedge part 5 Throw-away tip

Claims (2)

[Scope of utility model registration request] 1. A logarithmic decay rate is calculated from the following equation from the time change of the amplitude magnitude when the vibration of the bite holder is damped, and the logarithmic decay rate = 1 na _i / a _{i + 1} a _i : i Tool holder characterized in that the ratio of the second amplitude to the logarithmic decay rate is 2 to 4%. 2. The cutting tool according to claim 1, wherein the holder is made mainly of cast iron and is composed of another material.