• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.5
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• pp.45-52
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• 2002

In an end milling process, the undeformed chip section area and cutting forces vary periodically with the phase change of the tool. However, the real undeformed chip section area deviates from the geometrically ideal one owing to the cutter runout and tool shape error. In the current study, a method of estimating the real undeformed chip section area which reflects the cutter runout and tool shape error is presented during up-end milling processes of Inconel 718. The specific cutting forces, $K_r$ and $K_t$ are defined as the radial and tangential cutting forces divided by the modified chip section area, respectively. Both of the $K_{r}$ and $K_t$ values become smaller as the helix angle increases from $30^{\circ}$ to $40^{\circ}$. Whereas they become larger as the helix angle increases from $40^{\circ}$ to $50^{\circ}$. The $K_r$ and $K_t$ values show a tendency to decrease with increase of the modified chip section area.a.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.02a
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• pp.231-238
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• 2002

미세 절삭에 의한 마이크로 형상가공 및 이를 이용한 미세금형 가공기술개발을 위하여 절삭 공구를 이용한 기계적 미세 가공법에 대한 고찰과 더불어 shaping, end-milling, drilling 등의 가공이 가능한 기계적 미세 가공시스템을 구성하고 이를 이용한 미세 치형 그루브와 미세 격벽 등 미세 형상 구조의 금형 개발을 위한 가공실험을 수행하였다. 본 실험에서는 먼저 shaping 방식으로 세 종류의 다이아몬드 바이트를 사용하여 알루미늄, PMMA, Nickel, 황동 등의 소재에 pitch $150{\mu}m$, 높이 $8{\mu}m$ 내외의 미세 치형의 금형 코어를 가공하였고, 다음으로 Z축에 air spindle을 설치하여 $\phi0.2mm$의 end-mill(WC)을 사용하여 황동 소재에 깊이 $200{\mu}m$, 폭 $200{\mu}m,\;100{\mu}m,\;50{\mu}m,\;30{\mu}m$의 두께 변화를 주어 미세 격벽에 대한 가공실험을 하였다. 미세 구멍가공실험으로는 drilling 전용장비를 구성하여 $\phi0.6\~0.15mm$의 drill공구로 SM45C와 세라믹$(Si_3N_4-BN)$ 소재에 스텝이송방식에 의한 미세 구멍 가공 실험을 실시하였다.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.2
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• pp.79-86
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• 2002

In end milling process the undeformed chip thickness and the cutting force components vary periodically with phase change of the tool. In this study, up end milling process is transformed to the equivalent oblique cutting. The varying undeformed chip thickness and the cutting force components in end milling process are replaced with the equivalent average ones. Then it can be possible to analyze the chip-tool friction and shear process in the shear plane of the end milling process by the equivalent oblique cutting system. According to this analysis, when cutting Inconel 718, 61, 64 and 55% of the total energy is consumed in the shear process with the helix angle 30$^{\circ}$, 40$^{\circ}$ and 50$^{\circ}$ respectively, and the balance is consumed in the friction process. With the helix angle of 40$^{\circ}$ the specific cutting energy consumed is smaller than with the helix angle 30$^{\circ}$ and 50$^{\circ}$.