等間距螺旋刀具路徑建構於曲面切削之研究

Study of Constant-Interval Spiral Tool Paths Generation for Surface Machining

林智偉(Chih-Wei Lin)

指導教授 ： 蔡哲雄

國立臺北科技大學/機電學院/製造科技研究所/碩士(2012年)

摘要

切削曲面刀具路徑使用螺旋模式，可節省製程時間，並可使加工表面的切削痕跡流暢一致。許多螺旋刀具路徑規劃研究，並未考量殘留於加工曲面上的扇形餘料是否均勻。針對曲面以球形端銑刀精切削製程，本文提出一套螺旋刀具路徑的建構方法，能保持螺旋於曲面上等間距(或等節距)因而此螺旋路徑模式能兼顧殘留於加工曲面上的扇形餘料為等高，使加工面保有均勻的表面粗糙度，有利於加工面品質或後續的表面處理。本文建構螺旋刀具路徑切削模式，係由曲面中心點開始連續切削往外螺旋到曲面外圍，可以順時針或逆時針螺旋。以欲加工之曲面參數方程式為基礎，以及球端銑刀半徑資料與所要求之容許扇形餘料高之條件等，透過編寫的程式進行分析及疊代運算，可找到曲面上等間距螺旋刀具路徑各切削點資料，經轉換成刀端中心的移動座標軌跡即能進行切削模擬及輸出電腦數值控制(CNC)銑削加工程式實際於機台切削實驗。本文以三次方的Bézier曲面切削為例子，建構螺旋刀具路徑，經於CAD/CAM軟體實體切削模擬及CNC銑削結果顯示本文之螺旋切削路徑產生法確能滿足曲面加工殘留均勻扇形餘料的要求。

關鍵字

曲面切削 ； 等間距螺旋路徑 ； 等扇形高 ； Bézier曲面

並列摘要

Surface machining by using the spiral tool paths can save the cutting time and make the cutting traces of the machined surface smoothlier and more consistently. Most of spiral tool path planning studies did not consider whether the scallop residual on the machining surface is uniform or not. In this study, we proposed a new tool path planning method for spiral tool paths generation. This method can maintain the same spacing (constant-interval) of the spiral on the surface, so that the spiral tool paths can let the height of residual scallop material uniformly (uniform surface roughness) on the machined surface at the same time. This paper constructed a spiral tool path from the surface parametric center forward continously to the surface peripheral. Based on the information of the surface parametric equation, ball end mill radius, and the tolerance of scallop height, we can compute all the cutter contact points on the constant-interval spiral tool paths. Finally, for demonstration and verification, a cubic Bezier surface machining example was performed including spiral tool paths simulation in CAD/CAM system and practical machining on a CNC milling machine. The experimental results show that the spiral cutting path generated by present method can maintain the residual scallop material uniformly on the machined surface.

並列關鍵字

Surface machining ； Constant-interval spiral paths ； Iso-scallop height ； Bézier surface

參考文獻

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