A Study on Generation Mechanism of Work Hardened Surface Layer in Orthogonal Non-ferrous Metal Cutting

これまで，仕上げ加工は研削で行われてきたが，最近では切削加工機械の加工精度の向上に伴い，切取り厚さを非常に薄くした超精密切削加工に置き換わりつつある．したがって，切削条件や複雑な因子が切削加工面品位に及ぼす影響が問題となる．本研究では，加工面品位の一つとして加工硬化層を取り上げ，それに影響を及ぼす力学的因子について非鉄金属の二次元切削で実験的に検討した．その結果，加工硬化層の深さを支配するのは，せん断角や背分力のみならず，背分力の作用点，背分力の係数，母材硬さに相当する圧縮応力などであることが明らかになった．さらに，それらの力学的因子を用いた加工硬化層の深さの予測式についても検討した．Finish machining used to be carried out in grinding, but it is being replaced by cutting with very small undeformed chip thickness. In ultra precision process, the effect of the cutting conditions and the complicated factors on the machined surface integrity is a serious problem. In this research, work hardened surface layer was dealt with as an evaluation of the machined surface integrity and the effect of the mechanical factors on work hardening was investigated experimentally in orthogonal non-ferrous metal cutting. As a result, it was found that work hardened surface layer was affected not only by the shear angle varied under the cutting conditions and the thrust force of cutting resistance, but also by the thrust force action point and the stress-hardness diagram