【正文】 圖 3. 13球頭銑刀切削時(shí)的微元法分析 0n — 刀具處于前一位置時(shí)的曲面法向矢量； 1n — 刀具處于后一位置時(shí)的曲面法向矢量 pa — 刀頭沿 Z方向的縱向切深； 0pa — 曲面上 CC 點(diǎn)處的法向切深； h — 法向切深達(dá)到刀頭半徑邊緣時(shí)的法向切削深度； zd — 球頭銑刀刀頭進(jìn)行微分處理后的微元厚度； r — 切削微元的半徑； zf — 球頭銑刀的每齒進(jìn)給量。如圖 (a)及圖 (b)所示。是指刀具表面與曲面相切接觸的點(diǎn)。環(huán)切法加工刀具既可以由內(nèi)向外環(huán)切也可以由外向內(nèi)環(huán)切。即將刀具中心由工件輪廓線向待加工零件輪廓指定的一側(cè)偏移一個(gè)刀具半徑值。 為了對零件加工工藝參數(shù)的進(jìn)行合理選擇，必須考慮刀具軌跡的影響 。 (d)刀具的切削角度。 數(shù)控鉆削刀具優(yōu)選 鉆頭的設(shè)計(jì)歷史經(jīng)歷了 1800 年單刃鉆頭 → 1820 年麻花鉆頭 → 1900 年高速鋼麻花鉆頭 → 1930 年硬質(zhì)合金鉆頭 → 1970 年可轉(zhuǎn)位硬質(zhì)合金鑲片鉆頭 → 今天高性能硬質(zhì)合金鉆頭。如果刀具安裝低于中心高，將影響刀具的 加工性能。 刀具轉(zhuǎn)動 和車床加工不同，加工中心加工時(shí)由于刀具轉(zhuǎn)動，便不可能在加工中及時(shí)掌握刀尖的情況來調(diào)節(jié)進(jìn)刀量等。普通鋼刀桿作內(nèi)孔車削刀桿最大懸伸為4 倍桿徑，做內(nèi)螺紋車削刀桿為 3倍桿徑，做內(nèi)槽與仿形加工為 2倍桿徑，超出會有振動發(fā)生 。試調(diào)整徑向銑削寬度，確定銑刀直徑與徑向銑削寬度之比的工作，最好在高精度機(jī)床上進(jìn)行，以便在調(diào)整比率的同時(shí)，觀察其工件表面粗糙度的變化。 順銑和逆 銑的選擇 在進(jìn)行逆銑時(shí)，刀片從零切削厚度處開始切削，這會產(chǎn)生很高的切削力，從而推動銑刀和工件彼此遠(yuǎn)離。如果刀片出現(xiàn)裂紋，并且在切削時(shí)從刀片座中落下，刀體還將會受到嚴(yán)重的損壞。每個(gè)銑刀生產(chǎn)廠 家都有它自己的粗齒、密齒銑刀系列。壓制刀片的尺寸精度及刃口鋒利程度比磨制刀片差，但是壓制刀片的刃口強(qiáng)度較好，粗加工時(shí)耐沖擊并能承受較大的切深和進(jìn)給量。 數(shù)控銑削刀具優(yōu)選 現(xiàn)代銑削是種非常普遍的加工方式。目前，變參數(shù)優(yōu)化研究內(nèi)容主要是以最短加工時(shí)間為目標(biāo)、以切削力為約束的進(jìn)給量的優(yōu)化。只有這樣，數(shù)控仿真系統(tǒng)才會發(fā)揮更大的作用，才能成為完善的、真正意義上的仿真系統(tǒng)。 1983 年北京航空航天大學(xué)研制出銑床的微機(jī)自適應(yīng)數(shù)控系統(tǒng)，該系統(tǒng)可根據(jù)實(shí)測的主軸電機(jī)電樞電流來確定主軸力矩。 D. C. H. Yang, Z. Han 結(jié)合干涉檢查和刀具優(yōu)選提出了適合于自由曲面三軸數(shù) 控加工的刀具運(yùn)動軌跡生成方法 。隨著各種新型加工材料的不斷涌現(xiàn)，以及數(shù)控加工機(jī)床、加工中心和柔性 制造系統(tǒng)的廣泛運(yùn)用，僅依靠個(gè)人經(jīng)驗(yàn)來確定切削參數(shù) 陜西科技大學(xué)畢業(yè)論文 2 己遠(yuǎn)不能適應(yīng)時(shí)代的發(fā)展。 關(guān)鍵詞 :數(shù)控，優(yōu)化，工藝參數(shù)，切削用 量 II CNC machining parameter optimization analysis ABSTRACT In recent years, digital technology is toward highefficiency, high precision and high intelligent direction rapidly. Therefore, in order to improve the degree of automation of CNC machine tools, precision and efficiency as the goal to optimize a variety of CNC machining parameters and the optimized parameters were optimized, is both urgent and very practical significance. CNC machining tool is to determine the trajectory of an important part of CNC machining process. Tool trajectory design quality is good or bad, will directly affect the quality of the machining and processing costs. Since ball mill is the main plex surface machining tool, ball milling cutting force is to select tools, tools, fixtures and the milling process parameters optimization. Therefore, this paper trajectory ball mill is preferably carried out a theoretical study. As the CNC machining process, especially in plex surface machining process, the cutting conditions is not static, but in the current NC machining mostly artificial selection conservative cutting parameters, and in the process of cutting parameters remain unchanged, thus greatly reduced the productivity of CNC machine tools. In CNC machining, cutting parameters correctly reasonable choice to ensure the product quality, increase productivity, reduce production costs plays a very important role. In recent years, with the NC ((NC) technology, widely used, and a variety of advanced manufacturing technology is developing rapidly, production assistant time greatly reduced, and accordingly, the proportion of cutting time is greatly improved. Therefore shorten machining time, to improve production efficiency plays a very important role. Currently, most of the factories in the production of cutting experience or reference manual to select cutting, which often reach the most preferred cutting parameters. The use of modern cutting theory, mathematical modeling and model analysis approach seeks optimal bination of cutting parameters, cutting parameter selection is an important direction. Here mainly discussed the machining on CNC machine tools, the strike cutting optimization methods. Given in detail to strike the optimal cutting diagram and practical examples. Canada presents a cutting process parameters optimization method, obtained by this method can effectively cutting parameters improve processing efficiency, the craft workers from a lot of manual labor freed duplication and achieve cutting parameters selected scientific rationalization, standardization for enterprises to create a good economic benefits. III KEY WORDS： NC, optimization, process parameters, cuttiing IV 目 錄 摘 要 .................................................................... I ABSTRACT ................................................................ II 1 緒論 ................................................................... 1 本文選題目的及意義 ................................................ 1 數(shù)控加工刀具運(yùn)動軌跡的研究 ........................................ 2 工藝參數(shù)優(yōu)化的研究 ................................................ 2 數(shù)控加工在線參數(shù)優(yōu)化的國內(nèi)外發(fā)展?fàn)顩r ........................ 3 數(shù)控加工離線參數(shù)優(yōu)化的國內(nèi)外發(fā)展?fàn)顩r ........................ 4 本文研究的主要內(nèi)容 ................................................ 5 2 基于加工工藝參數(shù)的刀具優(yōu)選 ............................................. 6 數(shù)控銑削刀具優(yōu)選 .................................................. 6 銑刀刀片的選擇 .............................................. 6 銑刀刀體的選擇 .............................................. 7 切削時(shí)冷卻和涂層的選擇 ...................................... 7 順銑和逆銑的選擇 ............................................ 8 數(shù)控車削刀具優(yōu)選 .................................................. 9 車刀 的選用步驟 .............................................. 9 刀片材料和切削線速度 ........................................ 9 內(nèi)孔車刀桿的選擇基本原則 ................................... 10 數(shù)控膛削刀具優(yōu)選 ................................................. 10 刀具轉(zhuǎn)動 ................................................... 10 刀具的顛振 ................................................. 11 刀具的裝夾 ................................................. 11 切屑的排出 ................................................. 12 數(shù)控鉆削刀具優(yōu)選 ................................................. 12