Rotary cutting tool

Abstract

It is an object of the present invention to provide a rotary cutting tool that can divide chips at an appropriate size, suppress the incidence of edge chipping and damage attributed to chips to the cutting tool and a workpiece, extend the tool service life with regard to the machining of hard, brittle materials, and improve machining efficiency. The rotary cutting tool includes a hard coat film 3 coated onto a tip end section of a tool body 1 having a chip discharge groove 2. A rake face 6 is concavely provided in a cutting edge-side chip discharge groove formation surface 4 constituting the chip discharge groove 2 of the tool body 1, from a cutting edge 5 and along the cutting edge 5.

Description

technical field [0001] The invention relates to a rotary cutting tool, in particular to a rotary cutting tool suitable for cutting hard and brittle materials. Background technique [0002] For hard and brittle materials such as ceramics, glass, and superhard alloys, extremely fine chips are generated during cutting due to their material characteristics. Since the fine chips have high hardness, they act like abrasives, and cause not only defects of the cutting edge or accelerated wear, but also defects at the edge of the workpiece (so-called edge defects). [0003] Therefore, conventionally, various cutting tools for the purpose of suppressing the occurrence of edge defects during cutting of hard and brittle materials have been proposed (for example, Patent Document 1). [0004] Patent Document 1: Japanese Patent Laid-Open No. 2018-8363 [0005] However, in order to eliminate the above-mentioned problems in the cutting of hard and brittle materials, it can be considered to ...

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Problems solved by technology

[0005] However, in order to eliminate the above-mentioned problems in the cutting of hard and brittle materials, it can be considered to increase the feed rate of each blade to increase the discharged chips, but hard and brittle materials are not easy to increase chips due to the following reasons: it is easy The property of causing brittle fracture; in the case where a hard film with a certain thickness is formed on the surface of the tool used to process hard and brittle materials, the tip of the tool is given a rounded corner, which is useful for cutting The impact on performance cannot be ignored, the sharpness decreases and the cutting resistance increases; and in order to withstand the increased cutting resistance, the biting into the material to be cut has to be sacrificed and the tool shape that emphasizes the rigidity of the edge is formed, etc.

[0006] In addition, in the cutting of hard and brittle materials, if only the chip is increased, it may cause damage to the cutting tool or the material to be cut due to the biting of the chip during cutting.

As mentioned above, since the chip hardness of hard and brittle materials is high, damage caused by biting of chips is easy to occur. In addition, especially when the material to be cut is cemented carbide, the chips themselves are heavy, so sometimes It is also easy to cause poor discharge, even if the chip is too large, it will cause problems

[0007] In addition, as mentioned above, in the cutting of hard and brittle materials, the feed rate per edge of the cutting tool cannot be increased. In addition, under the condition of increasing the rotational speed (cutting speed) of the cutting tool, it is easy to promote the sharpness of the cutting edge. Wear, so it has to be processed with low processing efficiency, and there is also a problem that the processing time becomes longer

[0008] Furthermore, in conventional cutting tools, since the life is short, it is necessary to replace the tool judged to have reached the end of its life many times before the machining is completed, and it takes a lot of time (preparation, etc.) other than the actual machining. Moreover, when the cutting tool reaches the end of its life in the middle of processing, the cutting tool must be replaced at this time, and the sudden quality change of the processed surface may occur due to the replacement of the cutting tool. In the cutting of hard and brittle materials, there are currently many problems

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