本文主要是實驗探討使用端銑刀進行沉頭孔銑削之銑削條件,透過各種切削條件的切削力量測及銑製的孔徑、表面粗糙度及真圓度檢測以探討理想沉頭孔銑削法。本文實驗所使用的機台為三軸CNC銑床,主軸裝置銑削之端銑刀,在CNC床台上將鋁合金板材固定在動力計上後,運用CAD/CAM 軟體擬定之各項不同切削條件,及產生的三種刀具路徑(步階式側直進、中心直進及螺旋式)及其NC程式來進行切削實驗。各種切削條件包括端銑刀直徑、每刃進給、每步階間隔、切削速度以及步階式與螺旋式進給模式等。結果顯示,螺旋式相較於步階式,可使刀具承受之切削力較穩定以及可降低刀具之側向合力,並改善沉頭孔加工精度。以及沉頭孔銑削適當的端銑刀直徑約在沉頭孔孔徑的70%~80%之間。
In this paper, an investigation of counterbore milling conditions by using end mill cutters was performed. Using the measured milling forces and the machined counterbore quality (diameter accuracy and its roundness) to predict the ideal milling conditions for counterbore machining. A variety of milling conditions including the used end mill diameter, the interval of step type feeding method, the helical angle or pitch of helical type feeding method and the feed per tooth were planned. In contrast to the step type method, the experimental results show that the helical type feeding method can stabilize the cutting forces and reduce the lateral cutting force during milling process and improve the machined counterbore accuracy. As well as the appropriate end mill diameter of counterbore milling is between about 70% to 80% of the counterbore hole diameter.