| 摘要 |
PURPOSE: To prevent a cutter from breaking by forming a tool by selecting a cubic system boron nitride material having a specific characteristic according to a work material and by specifying a lathe cutting speed and a tool feeding speed, when very small grooves are turned in a hardened steel workpiece using a precision lathe. CONSTITUTION: When very small grooves are formed on the periphery of a workpiece such as an emboss roller used in a heat exchanger tube manufacturing line, a precision lathe or an ultraprecision lathe is used, and as a cutting tool 40, a cutting portion adhered with a layer of a cubic system boron nitride material 42 through an ultra hard alloy material 43 layer and a silver blazed material 44 layer is used. As the used cubic system boron nitride material 42, a material having high failure resistance is used when a hardened steel work piece contains relatively large carbide molecules (about 25-50μ), and a material having high hardness and abrasion resistance is used when it contains relatively small carbide molecules (less than 25μ). A turning machining is provided it a rotation speed of 80-200 m/min. and at a feeding speed of 5-20μper every rotation. |
