JP2009202283A - Cutware and method of making wavy shape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce friction between a tool and a material to be cut in cutting to lengthen a service life of a cutware, reduce cutting power and improve a nature of a finished surface. <P>SOLUTION: The cutware is used to form a fine wavy with a width of 1-20 μm and a depth of 0.1-10 μm on a surface of the cutware. By providing the fine wavy, waviness facilitates a behavior as an oil reservoir or reduces a contact area, thereby reducing the friction between the tool and a material to be cut. Thus cutting resistance and wear of the tool can be reduced. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cutting tool having a fine waviness shape on the rake face of the tool.

  In the cutting process, a great amount of cutting heat and frictional resistance are generated on the rake face of the tool due to the friction between the work material and the tool, causing a decrease in tool life and machined surface properties. As a method of improving this, a method of supplying oil during processing to produce an oil film between the tool and the material to be processed and performing processing while improving lubricity is generally performed. It is difficult to enter and its effect is not sufficient.

  In recent years, processing methods that use less oil, such as semi-dry processing and dry processing, have attracted attention from the viewpoint of reducing environmental burdens and processing costs. In these methods, the shortage of oil supply tends to become more prominent, and the above problem tends to appear due to the friction between the tool and the amount of work material.

In addition, in Patent Document 1 below, there is an example in which an oil sump is produced by grinding in the margin portion of the rotary tool, but since the width is large and it is difficult to arbitrarily set the shape, the effect is Not enough. Moreover, the tool is limited to a rotary tool. In Non-Patent Document 1, an oil sump is produced by making the surface of a milling tool into a segment shape, but its width is as large as 100 μm or more, and a sufficient effect cannot be obtained. In Non-Patent Document 2, a periodic structure or groove structure having a pitch of 800 nm and a depth of 150 nm is produced on the surface of a turning tool by utilizing interference and ablation by a femtosecond laser. On the other hand, due to problems such as the groove depth being too large, cutting does not work effectively.
JP 2005-319544 A Toshiyuki Enomoto, Keishi Watabe, Junichi Aoki, Naoto Otake, Development of Cutting Tools with Fine Surface Shape, Transactions of the Japan Society of Mechanical Engineers (C), 73, 729 (2007) 1560. Noritaka Kawashiki, Hideki Morimoto, Hiroshi Sugimori, Research and Development of Cutting Tools with Fine Periodic Structure, Toyama Prefectural Industrial Technology Center Research Report (2007) II-36.

  An object of the present invention is to reduce the friction between a tool and a material to be processed in cutting work, to extend the life of the cutting tool, to reduce cutting power, and to improve finished surface properties.

  In order to solve the above problems, in the present invention, a fine waviness shape is produced on the surface of the tool.

  The waviness is preferably 1 to 20 μm in width and 0.1 to 10 μm in depth, and the waviness is regularly arranged on the rake face of the cutting tool at intervals of 5 to 100 μm. The interval may be arranged not only when the interval is constant but also while changing the interval. These waviness shapes can be produced by the following method.

  In this method, a femtosecond laser having a beam diameter of several μm to several tens of μm is used, and scanning is performed at an arbitrary interval under a condition of energy density slightly larger than the processing threshold. As a result, a wavy shape can be produced on the surface of the tool with an accuracy of about 0.1 μm. At the same time, periodic structures having a width of 0.1 to 1.0 μm are produced by laser interference, but these structures do not act to improve friction in the present invention. The depth and width of the swell can be changed according to the energy density and the number of scans.

  Examples of the cutting tool to which the present invention is applied include cemented carbide, diamond, cBN, and high-speed tool steel. The tool shape does not depend on the presence or absence of a chip breaker for cutting chips.

  The present invention can also be applied to a coated tool.

  When a fine waviness is provided on the rake face of the tool, it comes into contact with the workpiece only at the waviness peak. This reduces the contact area between the tool and the work material. Further, the undulation valley portion acts as an oil reservoir, so that oil enters between the tool and the work material, and the oil film is easily maintained. Furthermore, pressure is generated when the oil flows from the undulating valley portion to the ridge portion, and the effect of increasing the oil film thickness is produced. By these actions, friction between the tool and the work material is reduced, and cutting resistance and tool wear can be suppressed.

  Moreover, since the cutting depth in cutting is usually several tens of μm to several mm, the shape corresponding to this processing unit is obtained by miniaturizing the undulation shape. For this reason, it becomes possible to acquire said effect efficiently. In addition, the above-described effect can be easily realized by making the swell shape finer, and a stronger effect can be obtained. Furthermore, by miniaturizing the swell, it becomes possible to avoid stress concentration caused by the shape of the surface, and the occurrence of cracks and the like can be suppressed.

  Hereinafter, the present invention will be specifically described with reference to examples. FIG. 1 shows a schematic view of a tool when the present invention is applied to a turning tool. The tool body includes a holder 4 and a tip 3 attached thereto. The tip end is composed of a rake face 2 on which the undulation 6 is produced and a flank face 5 on the side face thereof, and the intersecting portion becomes the cutting edge 1 for processing the material.

  FIG. 2 shows the waviness shape of the produced tool surface. Cemented carbide is used for the tool grade. By the above processing method, a wavy shape having a regular arrangement is produced.

In order to compare the present invention with a conventional tool, a cutting experiment was performed under the following conditions.
Work material ... Aluminum alloy tool material ... Cemented carbide cutting conditions ... Cutting speed: 600 m / min
... Feed amount: 0.1 mm / rev
... Cutting depth: 0.2 mm
FIG. 3 shows the cutting resistance when machining is performed with the inventive tool arranged in a direction perpendicular to and parallel to the direction of chip discharge. FIG. 4 shows the rake surface friction coefficient and the shear angle at that time. It can be seen that the cutting resistance is reduced by arranging the waviness in the vertical direction using the tool according to the present invention. This reduces the load on the tool and can extend the tool life. In addition, when the undulation is arranged in the vertical direction, the friction coefficient is small, and it can be seen that the reduction in cutting resistance is caused by the change in the lubricity of the rake face.

  FIG. 5 shows the cutting resistance when the undulation depth is changed. FIG. 6 shows the cutting resistance when the waviness interval is changed. It can be seen that the cutting force varies depending on the depth and interval of the swell. Under this experimental condition, the cutting resistance was the smallest when the depth was 2.9 μm and the interval was 15 μm. From this, the effect of the present invention can be controlled by the depth and interval of the undulation, and an optimal undulation shape can be arbitrarily produced according to the processing conditions and processing material.

  FIG. 7 shows the cutting resistance when the width of the undulation is changed. It can be seen that the cutting force varies depending on the width of the waviness. Under this experimental condition, the cutting resistance was the smallest when the width was 14 μm. Thus, the effect of the present invention can be controlled by the width of the undulation, and an optimal undulation shape can be arbitrarily produced according to the processing conditions, processing material, and the like.

  FIG. 8 shows the cutting force when machining using the inventive tool with DLC coating. By performing DLC coating, the lubricity of the tool is improved and the cutting resistance is reduced. Furthermore, the cutting resistance is further reduced by using the inventive tool with DLC coating. From this, it can be seen that the cutting resistance and wear resistance can be further improved by combining the present invention and the coating.

(A) Schematic top view of a turning tool to which the present invention is applied, (b) Schematic side view of a turning tool to which the present invention is applied, (c) Enlarged view of part A (A) Top view of tool, (b) Enlarged view of tool upper surface, (c) Enlarged view of tool side The figure which compared the cutting resistance of the tool which concerns on this invention, and the conventional tool The figure which compared the friction coefficient of the tool which concerns on this invention, and the conventional tool The figure which controlled cutting resistance by the depth of waviness using the tool concerning the present invention. The figure which controlled cutting resistance by the space | interval of waviness using the tool which concerns on this invention. The figure which controlled cutting resistance by the width of waviness using the tool concerning the present invention The figure which compared the cutting resistance of the coated tool which concerns on this invention, and the conventional tool

Explanation of symbols

1 Cutting Edge 2 Rake Face 3 Tip 4 Holder 5 Flank 6 Waviness

Claims (6)

  A cutting tool having a cutting edge at a tip thereof, wherein the rake face is provided with undulations.   2. The cutting tool according to claim 1, wherein the swell has a width of 1 [mu] m to 20 [mu] m and a depth of 0.1 [mu] m to 10 [mu] m.   The cutting tool according to claim 1 or 2, wherein the waviness is regularly arranged at intervals of 5 to 100 µm.   4. The cutting tool according to claim 1, wherein the coefficient of friction can be controlled by the direction of undulation, the width of undulation, the depth of undulation, and the interval of undulation.   The cutting tool according to any one of claims 1 to 4, wherein the surface of the cutting tool is coated with carbon-based DLC.   The fine waviness according to any one of claims 1 to 6, wherein at least the rake face of the cutting tool is scanned with a femtosecond laser having a beam diameter of several μm to several tens of μm under a condition of an energy density slightly larger than a processing threshold. A method for producing a swell on a cutting tool, which is characterized by being produced.