高速銑削與放電加工對模具鋼加工特性之探討

杜嘉祥(Jia-Xiang Du)

指導教授 ： 簡文通

國立屏東科技大學/工學院/機械工程系所/碩士(2010年)

https://doi.org/10.6346/NPUST.2010.00062

摘要

本研究以高速銑削與放電加工對模具鋼進行曲面加工，探討在達成相同加工形狀及拋光精度為基準時，比較高速銑削與放電加工對模具鋼加工特性之差異性。首先比較單一曲面理論加工表面粗糙度與實驗所得表面粗糙度的誤差量。接著使用田口法L9(34)直交表規劃實驗。分別求得表面平均粗糙度(Ra)及最大粗糙度(Rmax)為最小值時之最佳參數組合，並以其為基準調整路徑間距及每刃進給參數，探討其對表面粗糙度和加工時間的影響。最後以相同加工形狀及達到拋光精度為目標，進行高速銑削與放電加工對模具鋼加工特性之比較。研究結果顯示在比較理論與實驗印證粗糙度之誤差太大，主要原因為銑削曲面問題太複雜，不適用於理論公式推導。因此，本論文使用實驗切削為研究方法。由實驗得知高速銑削曲面，以最小表面粗糙度Ra及Rmax為目標時之最佳銑削參數組合，為切削間隙0.02mm(A1)、每刃進給0.04mm/tooth(B1) 、切削速度400mm/min(C1) 及切削深度0.1mm(D3)，可得到加工表面粗糙度Ra為0.102μm及Rmax為0.536μm，加工品質都達到拋光標準。在高速銑削與放電加工後再拋光的比較結果顯示，以相同加工形狀及達到拋光精度標準為目標，放電加工所需的加工時間是高速銑削加工時間的3.2倍，證明高速銑削的加工效率遠優於放電加工。

關鍵字

高速切削 ； SKD61模具鋼 ； 表面粗糙度 ； 放電加工

並列摘要

In this study the differences of mold steel curve surface machining characteristics by conducting with high-speed milling and electrical discharge processes have been investigated based on the same explored shape and polishing standard. Firstly, the error for surface roughness between the single curve surface theory and experimental work is performed. Then an orthogonal array of L9(34) is used to arrange experimental work. The combination of optimal parameters for searching minimum values of average surface roughness (Ra) and maximum surface roughness (Rmax) has been preformed, based on the conditions an investigation on the surface roughness and the working time by adjusting the baseline cutting gap and feed per tooth is also conducted. Finally, a comparison for the machined characteristics obtained form high-speed milling and electrical discharge processes is performed based on the same explore shape and polishing standard. It is shown that the theoretical method can not be used in this study due to the complex relations for milling a curved surface. Therefore, experimental work is applied in this study. A achievement in polishing standard for Ra is 0.102 μm and Rmax is 0.536μm has been found with the optimal parameters combination with the baseline cutting gap as 0.02 mm(A1), feed per tooth as 0.04 mm/tooth(B1), cutting speed as 400 mm/min(C1), and the depth of cut as 0.1 mm(D3). When conducting the comparison for processing time, a 3.2 times working time for electrical discharge with polished processes than for high-speed milling has been found. It is proved that the working efficiency for high-speed milling is much greater electrical discharge process.

並列關鍵字

High-Speed Cutting ； Mold Steel SKD61 ； Surface Roughness ； Electrical Discharge Processes

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