1, introduction
In recent years, in order to reduce the weight of aircraft, auto parts, aluminum alloy using volume increased year by year. Although the processing of aluminum alloy than when cutting the cutting resistance is small, but because the aluminum alloy is relatively soft, when the cutting blade is prone to sticking phenomenon, thus affecting the workpiece surface roughness. In order to increase the strength of aluminum alloy materials, usually in the aluminum alloy added to the bulk silicon. But as a result of silicon element in the form of particles dispersed in the aluminum alloy material, and the silica particles with very high hardness ( about 1000HV), thereby cutting will lead to the blade of the cutting tool wear. Therefore, such a high silicon aluminum alloy is a kind of difficult to machining materials.
Single crystal diamond tool applied in aluminum alloy precision machining can obtain good surface quality. Diamond cutting tools in machining of high silicon aluminum alloy material, can prevent the material of silicon particles lead to tool wear, tool has a longer life. If the single crystal diamond manufacturing with spiral groove and a complicated shape milling cutter blade, then the aluminum alloy material milling processing can achieve satisfactory effect. But because the single crystal diamond is expensive, on the other hand milling cutter three-dimensional complex shape, dimension precision, if the single crystal diamond cutter blade, then the forming process is very difficult, so the single crystal diamond cutter has not been widely applied.
In recent years, many domestic and foreign research institutions and manufacturers in artificial diamond coating technology development and application of a great deal of research, has yielded many new results, artificial diamond coating technology is developing very fast, in the cemented carbide milling cutter, drill, tap, blade tool surface coating has been widely applied. Artificial diamond coating technology and the successful application of the synthetic diamond coated tools favored, market demand year after year of growth. Nevertheless, artificial diamond coated cutting tool also has disadvantages: Although the diamond is the hardest substance found in nature, but its toughness is low, so in the processing of hard cutting materials easily occur when the film brittle breakage phenomenon; moreover diamond films diamond grains is more crystals, the surface is uneven, the rough surface can influence aluminum alloy workpieces to be machined surface roughness, and in the pit of easy to produce aluminum alloy adhesive, leading to early wear of diamond thin films.
In order to solve the above problems, Japan OSG recently developed super fine crystal diamond coating technology and successfully used for milling cutting tool coating.
2, super fine crystal diamond coated cutter cutting performance
In order to study the effect of superfine crystalline diamond coated cutter cutting performance, through cutting experiment on super fine crystal diamond coated cutter with and without coating super-hard cutter in the machining surface roughness, anti adhesion and film toughness and other aspects of the advantages and disadvantages are analyzed and compared.
2.1 to be machined surface roughness
Artificial diamond coating is formed on a surface of a substrate crystal nucleus ( small diamond particles), nuclei along the columnar growth of diamond polycrystalline aggregates. Diamond coating film surface is uneven, usually the surface roughness of Ry4 ~ 10 microns. Coated with diamond film cutting tools in the processing of aluminum alloy, the uneven surface shape can affect the machined surface roughness, it is difficult to get desired smooth surface finishing. Uncoated super hard alloy cutter although can obtain relatively smooth surface, but the blade of the cutting tool in a short process produces sticking phenomenon, thus affecting the surface roughness of the workpiece edge and lead to early wear, to reach the expected service life. OSG company developed super fine crystal diamond film is not smooth, and with ordinary diamond coated cutter surface, ultra-fine crystalline diamond film coated cutter surface has good gloss.
Using super fine crystal diamond coated 10mm milling cutter for aluminum alloy material of A7075 cutting test. The cutting conditions: line speed of 200m / min, 0.05mm / edge cutting feed rate, depth of cut 0.1 * 10mm. Experimental results show is the processing of aluminum alloy workpiece surface with and without coating super-hard cutter processing of the surface have the same level of smoothness.
The 2.2 blocking resistance
Diamond cutting tools in dry cutting of aluminum alloy with excellent blocking resistance. Metal compound film ( such as TiN, TiCN, TiAlN, CrN etc.) although there are good processing properties, but in the process of cutting thin film will soon wear. The film is abraded, the surface can change shape and even exposed surface of the substrate, thereby causing the adhesion of aluminum alloy. While diamond film coated tool in the processing of aluminum alloy abrasion is very small, after being used for a long time still has good blocking resistance and maintain good cutting performance.