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CIRP Annals - Manufacturing Technology 59 (2010) 597–600

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CIRP Annals - Manufacturing Technology
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Improving anti-adhesive properties of cutting tool surfaces by nano-/micro-textures
T. Enomoto *, T. Sugihara
Department of Mechanical Engineering, Graduate School ofEngineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan Submitted by T. Matsuo (1), Osaka, Japan.

A R T I C L E I N F O

A B S T R A C T

Keywords: Cutting tool Surface Texture

Demand for aluminum alloy composites has rapidly increased, especially in the transport industry. This demand is due to such key advantages as a high strength to mass ratio and high corrosionresistance. However, aluminum chips readily adhere to the cutting edge of the tool used, often leading to tool breakage. To address this problem, we have developed cutting tools with nano-/micro-textured surfaces formed using femtosecond laser technology. Face-milling experiments on aluminum alloys showed that the textured surface significantly improves the lubricity and anti-adhesive properties at thetool–chip interface. ß 2010 CIRP.

1. Introduction Aluminum alloys provide several advantages, including a high strength to mass ratio and high corrosion resistance. Hence, the demand for aluminum alloys has rapidly increased, especially in the transport industry. Compared to steel, aluminum alloys are easy to cut because of their low hardness, but this advantage is sometimes countered in certainapplications by their low melting point and high ductility, which cause aluminum chips to adhere to the cutting edges of tools, leading to tool failure [1]. Many different parameters of cutting tools have been improved, such as geometry, surface coating [2], and finishing. For example, diamond-like carbon (DLC) coated tools with extremely low friction are being applied in the dry or near drycutting of aluminum alloys [3], but a flooded cutting fluid is required in practical use to avoid adherence of aluminum chips to DLC-coated tools [4]. Further, tool breakage occurs frequently in cutting processes such as deep hole drilling, milling, and tapping, in which it is difficult to directly supply cutting fluid to the cutting point. To solve the problems described above, we adopted a surfaceengineering approach, namely, a functionalization of tool surfaces by textures [5,6]. We developed a micro-textured cutting tool to determine the role of the textured tool rake face in retaining cutting fluid [7], revealing that the surface significantly improved lubricity as indicated by the evaluation of the shear angle, the cutting forces, and the coefficient of friction of the tool rake face. Thetool–chip adhesion has not yet been investigated. In this study, we evaluated the anti-adhesive effect of the micro-textured surface and developed techniques to improve the effect using more refined surface textures. On the basis of our findings, we developed a cutting tool with a nano-/micro-textured

surface to improve the desired anti-adhesive effect. We also evaluated the corresponding cuttingperformance. 2. Micro-textured cutting tool surfaces 2.1. Cutting tools with micro-textured surfaces Fig. 1 shows both a schematic illustration and a scanning electron microscope (SEM) (Hitachi High-Technologies Corp., S3400NX) image of a cutting tool with a micro-textured segmented DLC coating [7]. We prepared the tool based on [8]. First, DLC film was uniformly coated on the rake face of a cementedcarbide tool (Sumitomo Electric Hardmetal Corp., SEKN42M) by the plasma-enhanced chemical vapor deposition (CVD) method. Next, a tungsten mesh wire was set above the coated tool face to serve as a mask to create a grid. A second layer of DLC was then coated by the CVD method, resulting in a DLC film with segment size 150 mm  150 mm and 0.8 mm deep grid grooves spaced at 80 mm. 2.2. Cutting...