裝配圖機(jī)床刀架座加工工藝工裝設(shè)計(jì)
裝配圖機(jī)床刀架座加工工藝工裝設(shè)計(jì),裝配,機(jī)床,刀架,加工,工藝,工裝,設(shè)計(jì)
南昌航空大學(xué)科技學(xué)院學(xué)士學(xué)位論文
中文部分
切削加工新概念
現(xiàn)今的刀具公司再也不能只是制造和銷(xiāo)售刀具，為了成功，他們必須與全球化制造趨勢(shì)保持一致，通過(guò)提高效率、同客戶(hù)合作來(lái)降低成本。在這個(gè)近乎瞬間的全球競(jìng)爭(zhēng)的后NAFTA、后WTO時(shí)代，全世界的公司正對(duì)相同感覺(jué)作出更快、更輕、更便宜的反應(yīng)。換句話說(shuō)，他們制造的產(chǎn)品和零件包含能在高速下運(yùn)轉(zhuǎn)，由于成本的壓力，最好、更輕而且要制造更便宜。取得這些目標(biāo)的一個(gè)最佳途徑是通過(guò)發(fā)展和應(yīng)用新材料，但這些新的和改進(jìn)的材料通常都難以加工。這種商業(yè)上的動(dòng)力和技術(shù)上的困難的組合在汽車(chē)和航空工業(yè)尤其突出，并已成為有見(jiàn)識(shí)的刀具公司研發(fā)部門(mén)的首要驅(qū)動(dòng)力。
例如，拿球墨鑄鐵來(lái)說(shuō)，它已成為發(fā)動(dòng)機(jī)零件和其它汽車(chē)、農(nóng)用設(shè)備和機(jī)床工業(yè)上的零件的日益見(jiàn)的材料。這種合金提供較低的生產(chǎn)成本和良好的機(jī)械性能的組合。他們比鋼材便宜，而比鑄鐵有更高的強(qiáng)度和韌性。但同時(shí)球墨鑄鐵非常耐磨，有快速磨壞刀具材料的傾向。這種耐磨性很大程度上受珠光體含量影響。某一已知球墨鑄鐵的珠光體含量越高，它的耐磨性越好，而且它的可加工性越差。另外，球墨鑄鐵的多孔性導(dǎo)致斷續(xù)切削，這更加降低壽命。
可以預(yù)計(jì)，高硬度和高耐磨的切削材質(zhì)需考慮球墨鑄鐵的高耐磨性。并且事實(shí)上材質(zhì)包含極硬的TiC（碳化鈦）或TiCN（碳氮化鈦）的厚涂層在切削速度每分鐘300米時(shí)加工球墨鑄鐵被證明通常是有效的。但是隨著切削速度的增加，切屑/刀具結(jié)合面的溫度也在增加。當(dāng)發(fā)生這樣的情況，TiC涂層傾向于和鐵發(fā)生化學(xué)反應(yīng)并軟化，更多的壓力作用在抗月牙洼磨損的涂層上。在這些條件下，希望有一種化學(xué)穩(wěn)定性更好的涂層，如Al2O3（雖然在較低的速度下不如TiC硬或耐磨）。
化學(xué)穩(wěn)定性比耐磨性更成為一個(gè)重要的表現(xiàn)性能分界的因素，速度和溫度取決于被加工球墨鑄鐵的晶粒結(jié)構(gòu)和性能。但是通常厚涂層的TiC或TiCN和僅有氧化物的較薄涂層是針對(duì)球墨鑄鐵應(yīng)用的，因?yàn)榻裉齑蟛糠诌@類(lèi)被加工材料的切削速度在每分鐘150到335米之間。對(duì)于速度高于每分鐘300米的應(yīng)用，人們對(duì)這種材料是滿(mǎn)意的。
為了使這個(gè)范圍性能最優(yōu)，山高研發(fā)和推出了針對(duì)球墨鑄鐵加工的材質(zhì)TX150。這種材質(zhì)有一個(gè)硬且抗變形的基體，對(duì)于加工球墨鑄鐵很理想。它的涂層由一層較厚的很耐磨的碳氮化鈦和一層較薄的抗月牙洼磨損的氧化物涂層，頂面是一薄層TiN。這種涂層運(yùn)用目前工藝水平的產(chǎn)生耐磨性和抗月牙洼磨損需要的CVD涂層的全部硬度而且韌性平滑性增加的中溫化學(xué)氣相沉積（MTCVD）工藝?；w/涂層的組合性能給予很高的抗塑性變形和刃口微崩能力，使之成為正常速度下加工球墨鑄鐵的理想材質(zhì)。
涂層陶瓷也表現(xiàn)出能有效加工球墨鑄鐵。在過(guò)去，未涂層的韌性較好的諸如氮化硅和碳化硅纖維強(qiáng)化的氧化鋁陶瓷應(yīng)用受工件材料化學(xué)親和性的限制。但是今天通過(guò)使用能抵抗切屑變形過(guò)程產(chǎn)生高熱量的涂層刀具壽命已經(jīng)顯著增加。而某些早期這個(gè)領(lǐng)域的工件加工使用氧化鋁涂層晶須強(qiáng)化陶瓷，今天的多數(shù)研究活動(dòng)集中于TiN涂層氮化硅。這種涂層能顯著拓寬韌性較好的陶瓷的應(yīng)用范圍。
切削加工時(shí)，工件的已加工表面是依靠切削工具和工件作相對(duì)運(yùn)動(dòng)來(lái)獲得的。按表面形成方法，切削加工可分為刀尖軌跡法、成形刀具法、展成法三類(lèi)。
刀尖軌跡法是依靠刀尖相對(duì)于工件表面的運(yùn)動(dòng)軌跡，來(lái)獲得工件所要求的表面幾何形狀，如車(chē)削外圓、刨削平面、磨削外圓、用靠模車(chē)削成形面等，刀尖的運(yùn)動(dòng)軌跡取決于機(jī)床所提供的切削工具與工件的相對(duì)運(yùn)動(dòng)；
成形刀具法簡(jiǎn)稱(chēng)成形法，是用與工件的最終表面輪廓相匹配的成形刀具，或成形砂輪等加工出成形面，如成形車(chē)削、成形銑削和成形磨削等，由于成形刀具的制造比較困難，因此一般只用于加工短的成形面；
展成法又稱(chēng)滾切法，是加工時(shí)切削工具與工件作相對(duì)展成運(yùn)動(dòng)，刀具和工件的瞬心線相互作純滾動(dòng)，兩者之間保持確定的速比關(guān)系，所獲得加工表面就是刀刃在這種運(yùn)動(dòng)中的包絡(luò)面，齒輪加工中的滾齒、插齒、剃齒、珩齒和磨齒等均屬展成法加工。有些切削加工兼有刀尖軌跡法和成形刀具法的特點(diǎn)，如螺紋車(chē)削。
切削加工質(zhì)量主要是指工件的加工精度和表面質(zhì)量(包括表面粗糙度、殘余應(yīng)力和表面硬化)。隨著技術(shù)的進(jìn)步，切削加工的質(zhì)量不斷提高。18世紀(jì)后期，切削加工精度以毫米計(jì)；20世紀(jì)初，切削加工的精度最高已達(dá)0.01毫米；至50年代，切削加工精度已達(dá)微米級(jí)；70年代，切削加工精度又提高到0.1微米。
影響切削加工質(zhì)量的主要因素有機(jī)床、刀具、夾具、工件毛坯、工藝方法和加工環(huán)境等方面。要提高切削加工質(zhì)量，必須對(duì)上述各方面采取適當(dāng)措施，如減小機(jī)床工作誤差、正確選用切削工具、提高毛坯質(zhì)量、合理安排工藝、改善環(huán)境條件等。
提高切削用量以提高材料切除率，是提高切削加工效率的基本途徑。常用的高效切削加工方法有高速切削、強(qiáng)力切削、等離子弧加熱切削和振動(dòng)切削等。
磨削速度在45米／秒以上的切削稱(chēng)為高速磨削。采用高速切削(或磨削)既可提高效率，又可減小表面粗糙度。高速切削(或磨削)要求機(jī)床具有高轉(zhuǎn)速、高剛度、大功率和抗振性好的工藝系統(tǒng)；要求刀具有合理的幾何參數(shù)和方便的緊固方式，還需考慮安全可靠的斷屑方法。
強(qiáng)力切削指大進(jìn)給或大切深的切削加工，一般用于車(chē)削和磨削。強(qiáng)力車(chē)削的主要特點(diǎn)是車(chē)刀除主切削刃外，還有一個(gè)平行于工件已加工表面的副切削刃同時(shí)參與切削，故可把進(jìn)給量比一般車(chē)削提高幾倍甚至十幾倍。與高速切削比較，強(qiáng)力切削的切削溫度較低，刀具壽命較長(zhǎng)，切削效率較高；缺點(diǎn)是加工表面較粗糙。強(qiáng)力切削時(shí)，徑向切削力很大故不適于加工細(xì)長(zhǎng)工件。
振動(dòng)切削是沿刀具進(jìn)給方向，附加低頻或高頻振動(dòng)的切削加工，可以提高切削效率。低頻振動(dòng)切削具有很好的斷屑效果，可不用斷屑裝置，使刀刃強(qiáng)度增加，切削時(shí)的總功率消耗比帶有斷屑裝置的普通切削降低40％左右。高頻振動(dòng)切削也稱(chēng)超聲波振動(dòng)切削，有助于減小刀具與工件之間的摩擦，降低切削溫度，減小刀具的粘著磨損，從而提高切削效率和加工表面質(zhì)量，刀具壽命約可提高40％。
對(duì)木材、塑料、橡膠、玻璃、大理石、花崗石等非金屬材料的切削加工，雖與金屬材料的切削類(lèi)似，但所用刀具、設(shè)備和切削用量等各有特點(diǎn)。
木材制品的切削加工主要在各種木工機(jī)床上進(jìn)行，其方法主要有：鋸切、刨切、車(chē)削、銑削、鉆削和砂光等。
塑料的剛度比金屬差，易彎曲變形，尤其是熱塑性塑料導(dǎo)熱性差，易升溫軟化。故切削塑料時(shí)，宜用高速鋼或硬質(zhì)合金刀具，選用小的進(jìn)給量和高的切削速度，并用壓縮空氣冷卻。若刀具鋒利，角度合適，可產(chǎn)生帶狀切屑，易于帶走熱量。
玻璃(包括鍺、硅等半導(dǎo)體材料)的硬度高而脆性大。對(duì)玻璃的切削加工常用切割、鉆孔、研磨和拋光等方法。對(duì)厚度在三毫米以下的玻璃板，最簡(jiǎn)單的切割方法是用金剛石或其他堅(jiān)硬物質(zhì)，在玻璃表面手工刻劃，利用刻痕處的應(yīng)力集中，即可用手折斷。
對(duì)大理石、花崗石和混凝土等堅(jiān)硬材料的加工，主要用切割、車(chē)削、鉆孔、刨削、研磨和拋光等方法。切割時(shí)可用圓鋸片加磨料和水；外圓和端面可采用負(fù)前角的硬質(zhì)合金車(chē)刀，以10～30米／分的切削速度車(chē)削；鉆孔可用硬質(zhì)合金鉆頭；大的石料平面可用硬質(zhì)合金刨刀或滾切刨刀刨削；精密平滑的表面，可用三塊互為基準(zhǔn)對(duì)研的方法，或磨削和拋光的方法獲得。
刀具在熱強(qiáng)合金中的應(yīng)用
航空加工也變化迅速。例如，鎳基高溫合金如幾年前多數(shù)人未聽(tīng)說(shuō)過(guò)的Rene88現(xiàn)在占到航空發(fā)動(dòng)機(jī)制造使用總金屬量的10~25%。對(duì)于這個(gè)有很好的表現(xiàn)和商業(yè)理由。例如，這些熱強(qiáng)合金能增加發(fā)動(dòng)機(jī)壽命而且允許較小的發(fā)動(dòng)機(jī)工作在大飛機(jī)上，那將提高燃燒效率并降低運(yùn)營(yíng)成本。這些韌性好的材料也把費(fèi)用呈現(xiàn)在刀具上。它們的耐熱性導(dǎo)致刀尖上的溫度更高，從而降低了刀具壽命。相似地，這些合金里的碳化物顆粒顯著增加了摩擦，從而縮短刀具壽命。
作為這些條件改變的結(jié)果，曾經(jīng)能很滿(mǎn)意地加工很多鈦合金和鎳基合金的硬質(zhì)合金材質(zhì)C-2在應(yīng)用到當(dāng)今的合金時(shí)遭受切削刃的壓碎和切削深度線處嚴(yán)重的溝槽磨損。但是用最新的細(xì)顆粒硬質(zhì)合金能有效加工高溫合金，刀具壽命得到提高，更重要的是提高在高溫合金應(yīng)用時(shí)的可靠性。細(xì)顆粒硬質(zhì)合金有比傳統(tǒng)硬質(zhì)合金材質(zhì)更高的壓縮強(qiáng)度和硬度，只是在韌性方面增加少量的成本。而結(jié)果是在高溫合金加工上比傳統(tǒng)硬質(zhì)合金抵抗常見(jiàn)失效模式更有效。
PVD（物理氣相沉積）涂層也被證明有效加工高溫合金。TiN（氮化鈦）PVD涂層是最早使用的并仍然是最受歡迎的。最近，TiAlN（氮鋁化鈦）和TiCN（碳氮化鈦）涂層也能很好使用。過(guò)去TiAlN涂層應(yīng)用范圍和TiN相比限制更多。但是當(dāng)切削速度提高后它們是一個(gè)很好的選擇，在那些應(yīng)用提高生產(chǎn)率達(dá)40%。另一方面，在較低的切削速度下取決于涂層的表面工況TiAlN會(huì)導(dǎo)致積屑瘤、隨后的微崩和溝槽磨損。
近來(lái)，用于高溫合金應(yīng)用的材質(zhì)已經(jīng)發(fā)展了，這些涂層由幾層組合而成。大量的實(shí)驗(yàn)室和現(xiàn)場(chǎng)測(cè)試已經(jīng)論證了這種組合和其它任何一種單一涂層相比在很寬范圍的應(yīng)用時(shí)很有效。因此針對(duì)高溫合金應(yīng)用的PVD復(fù)合涂層可能成為硬質(zhì)合金新材質(zhì)研發(fā)持續(xù)的焦點(diǎn)。和MTCVD涂層、涂層陶瓷集合在一起，它們有望成為更有效加工正在研發(fā)的新的更難加工工件材料的主要沖擊力量。
干切削，包括冷卻液在內(nèi)的問(wèn)題是刀具制造的科技和商業(yè)擴(kuò)大產(chǎn)業(yè)化趨勢(shì)的另一個(gè)領(lǐng)域。北美和歐洲嚴(yán)格冷卻液管理的要求和最大的三家汽車(chē)制造商強(qiáng)制它們的核心供應(yīng)商取得ISO14000認(rèn)證（ISO9000的環(huán)境管理版本），這使得冷卻液處理成本上升。對(duì)汽車(chē)公司和他們核心供應(yīng)商來(lái)說(shuō)明顯受歡迎的反應(yīng)之一是在特定的加工應(yīng)用里完全免除冷卻液的使用。這種干加工的新世界給刀具供應(yīng)商提出了一系列挑戰(zhàn)。
最近，已經(jīng)出現(xiàn)了一些有關(guān)這個(gè)專(zhuān)題揭示速度、進(jìn)給、涂層化學(xué)成分和其它參數(shù)的很充實(shí)的綜合性很強(qiáng)的有用的技術(shù)文章。在這里我想集中論述在操作和商業(yè)含義上的汽車(chē)制造商的新“干加工觀點(diǎn)”。
金屬加工從業(yè)人員能很好理解有關(guān)冷卻液使用的問(wèn)題，但大多數(shù)不能理解有關(guān)除在刀具-工件接觸面間技術(shù)挑戰(zhàn)（例如排屑）之外的干加工問(wèn)題。通常可以觀察到流出的冷卻液分散切屑，但壓力超過(guò)3000磅/英寸2的高速冷卻液也能幫助斷屑，特別是軟且連續(xù)的切屑會(huì)引起刀具-工件接觸面上的麻煩。
采用干切削工藝的零件的結(jié)果是機(jī)床比采用濕式加工零件的更熱。你是否允許它們測(cè)量前在露天自然冷卻？如果新加工的熱零件經(jīng)常放到周轉(zhuǎn)箱，升高周?chē)h(huán)境溫度，是否零件充分冷卻并正好足夠允許精度檢測(cè)？還有處置身邊幾十上百的零件會(huì)對(duì)操作工人增加額外負(fù)擔(dān)。
同許多刀具/工件的技術(shù)問(wèn)題一起，這些潛在的問(wèn)題需要陳述是否干加工能行。幸運(yùn)地，有很多途徑闡述這些問(wèn)題。例如，壓縮空氣被證明在很多應(yīng)用里排屑成為問(wèn)題的場(chǎng)合有成功的反響。
另一個(gè)方案是叫做MQL（最小量潤(rùn)滑）的技術(shù)，它由應(yīng)用代替?zhèn)鹘y(tǒng)冷卻液的相當(dāng)少量油霧構(gòu)成。這是一個(gè)公認(rèn)的折中方案，這種最小量技術(shù)會(huì)大幅度減少冷卻液的頭疼事，而且在許多應(yīng)用里加工出的光潔度也很好。這個(gè)領(lǐng)域仍然有很多研究在做，而且刀具公司積極參與這樣的研究是絕對(duì)必要的。如果他們不做將落后于競(jìng)爭(zhēng)對(duì)手，處于不利的地位。
根據(jù)世界上工廠內(nèi)具體情況設(shè)計(jì)出別的也許更好的方案。制造業(yè)從業(yè)人員可能仍然會(huì)問(wèn)為什么他們要努力使用新發(fā)展的技術(shù)代替?zhèn)鹘y(tǒng)的已經(jīng)經(jīng)歷數(shù)代人改進(jìn)提高的冷卻液方法，尤其因?yàn)閷?shí)施干加工或半干加工產(chǎn)生的試驗(yàn)和失敗可能引起更高的短期刀具成本。簡(jiǎn)明的答案是當(dāng)?shù)镀蠹s占典型加工零件成本的3%時(shí)，冷卻液的成本（從購(gòu)買(mǎi)到維護(hù)、儲(chǔ)存、處理）會(huì)占零件成本的15%。
干加工也許不是對(duì)每個(gè)應(yīng)用都適合，但象上面討論的其它加工問(wèn)題一樣，需要從更寬的操作、環(huán)境和商業(yè)角度來(lái)評(píng)價(jià)。能幫助客戶(hù)這樣做的刀具公司將有競(jìng)爭(zhēng)優(yōu)勢(shì)，而那些不能提供的將不斷處于被動(dòng)地位。
刀具和納米技術(shù)
一個(gè)能劇烈改變刀具工業(yè)的迷人的新領(lǐng)域是微型制造，或處理微小粒子形成所需的產(chǎn)品。要談及的關(guān)于刀具微型制造的第一件事是它這里還沒(méi)有；第二件要說(shuō)的事是它并不遙遠(yuǎn)。
為什么微型制造和刀具相關(guān)。因?yàn)樽钪饕氖穷w粒尺寸越小，硬質(zhì)合金材料韌性越好且更耐磨。用納米級(jí)顆粒（一些專(zhuān)家定義為小于0.2μm，而其他人堅(jiān)持納米顆粒要小于0.1μm）制造的硬質(zhì)合金刀具原型已經(jīng)做好并測(cè)試,據(jù)稱(chēng)耐磨性戲劇性地增加。問(wèn)題是納米級(jí)的硬質(zhì)合金顆粒不能靠粉碎較大的材料形成，它們一定得通過(guò)更小的材料構(gòu)成，而處理分子級(jí)粒子還不是一件容易和經(jīng)濟(jì)的事情。
英文部分
The new concept of cutting processing
The nowadays cutting tool company cannot only be again the manufacture and the sales cutting tool, in order to succeed, they must be consistent with the globalization manufacture tendency maintenance, through enhances the efficiency, cooperates with the customer reduces the cost. Approaches the instantaneous global competition after this after NAFTA, the WTO time, the world company is making quickly to the same feeling, is lighter, a cheaper response. In other words, they make the product and the components contain can in high speed under revolve, as a result of the cost pressure, best, is lighter moreover must make cheaply. Obtains these goals a best way is through develops and applies the new material, but these is new and the improvement material usually all with difficulty processes. In in this kind of commercial power and the technical difficulty combination is especially prominent in the automobile and the aviation industry, and has become has the experience the cutting tool company to research and develop the department the most important driving influence.
For example, takes the modular cast iron to say that, it has become the engine part and other automobiles, the agriculture the material which see day by day with the equipment and in the machine tool industry components. This kind of alloy provides the low production cost and the good machine capability combination. They are cheaper than the steel products, but has a higher intensity and toughness compared to the cast iron. But at the same time the modular cast iron is extremely wear-resisting, has fast breaks by rubbing the cutting tool material the tendency. In this wear resistant very great degree bead luminous body content influence. Some known modular cast iron bead luminous body content higher, its resistance to wear better, moreover its machinability is worse. Moreover, the modular cast iron porosity causes off and on to cut, this even more reduces the life.
May estimate that, the high degree of hardness and the high wear-resisting cutting material quality must consider the modular cast iron the high resistance to wear. And the material quality contains extremely hard TiC in fact (carbonized titanium) or TiCN (carbon titanium nitrides) thick coating when cutting speed each minute 300 meters processes the modular cast iron to prove usually is effective. But along with cutting speed increase, scrap/The cutting tool junction plane temperature also is increasing. When has such situation, the TiC coating favors in has the chemical reaction with the iron and softens, more pressures function in anti- crescent moon hollow attrition coating. Under these conditions, hoped has one chemical stability better coating, like Al2O3 (although under low speed was inferior to TiC hard or is wear-resisting).
The chemical stability becomes an important performance performance dividing line compared to the resistance to wear the factor, the speed and the temperature is decided in is processed the modular cast iron the crystal grain structure and the performance. But usually thick coating of TiCN and TiC or only ductile iron oxides in the soil coating is applied to, because the today majority of this kinds are processed the material the cutting speed in each minute 150 to 335 meters between. Is higher than each minute 300 meter applications regarding the speed, the people to this kind of material are satisfied.
In order to cause this scope performance to be most superior, the mountain high researched and developed and has promoted in view of modular cast iron processing material quality TX150. This kind of material quality has hard also the anti- distortion substrate, is very ideal regarding the processing modular cast iron. Its coating the oxide compound coating which hollowly wears by thick very wear-resisting carbon titanium nitrides and a thin anti- crescent moon, the top is thin layer TiN. This kind of coating which needs the center warm chemistry gas phase deposition using the state of the art production resistance to wear and the anti- crescent moon hollow attrition which the CVD coating complete degree of hardness moreover the tough smoothness increases (MTCVD) the craft. Substrate/The coating combination performance gives the very high anti- plastic deformation and the cutting edge micro collapses the ability, causes it to become under the normal speed to process the modular cast iron the ideal material quality.
The coating ceramics also display can effectively process the modular cast iron. In the past, the aluminum oxide ceramics application which not the coating tough good such as nitriding silicon and the silicon carbide textile fiber strengthened the work piece material chemistry paralysis limit. Today but could resist the scrap distortion process through the use to have the high thermal coating cutting tool life already remarkably to increase. But certain early this domains work piece processing use aluminum oxides spread the layer crystals to have to strengthen the ceramics, today most research concentrate in the TiN coating nitriding silicon. This kind of coating can remarkably open up the tough good ceramics the application scope.
When machining, the work piece has processed the surface is depends upon the cutting tool and the work piece makes the relative motion to obtain.According to the surface method of formation, the machining may divide into the knife point path law, the formed cutting tool law, the generating process three kinds.
The knife point path law is depends upon the knife point to be opposite in the work piece surface path, obtains the superficial geometry shape which the work piece requests, like the turning outer annulus, the shaping plane, the grinding outer annulus, with the profile turning forming surface and so on, the knife point path are decided the cutting tool and the work piece relative motion which provides in the engine bed;
The formed cutting tool law abbreviation forming, is with the formed cutting tool which matches with the work piece final superficial outline, or the formed grinding wheel and so on processes the formed surface, like formed turning, formed milling and form grinding and so on, because forms the cutting tool the manufacture quite to be difficult, therefore only uses in processing the short formed surface generally;
The generating process name rolls cuts method, is when the processing the cutting tool and the work piece do unfold the movement relatively, the cutting tool and the work piece centrode make the pure trundle mutually, between both maintains the definite transmission ratio relations, obtains the processing surface is the knife edge in this kind of movement envelope, in the gear processing rolls the tooth, the gear shaping, the shaving, the top horizontal jade piece tooth and rubs the tooth and so on to be the generating process processing.Some machining has at the same time the knife point path law and the formed cutting tool method characteristic, like thread turning.
The machining quality mainly is refers to the work piece the processing precision and the surface quality (including surface roughness, residual stress and superficial hardening).Along with the technical progress, the machining quality enhances unceasingly.The 18th century later periods, the machining precision counts by the millimeter; At the beginning of 20th century, machining precision Gao Yida 0.01 millimeter; To the 50's, the machining precision has reached a micron level; The 70's, the machining precision enhances to 0.1 micron.
The influence machining quality primary factor has aspects and so on engine bed, cutting tool, jig, work piece semifinished materials, technique and processing environment.Must improve the machining quality, must take the suitable measure to the above various aspects, like reduces the engine bed work error, selects the cutting tool correctly, improves the semifinished materials quality, the reasonable arrangement craft, the improvement environmental condition and so on.
Enhances the cutting specifications to enhance the material excision rate, is enhances the machining efficiency the essential way.The commonly used highly effective machining method has the high-speed cutting, the force cutting, the plasma arc heating cuts and vibrates the cutting and so on.
The grinding speed is called the high-speed grinding in 45 meters/second above cuttings.Uses the high-speed cutting (or grinding) both may enhance the efficiency, and may reduce the surface roughness.The high-speed cutting (or grinding) requests the engine bed to have the high speed, the high rigidity, the high efficiency and the vibration-proof good craft system; Requests the cutting tool to have the reasonable geometry parameter and the convenience tight way, but also must consider the safe reliable chip breaking method.
The force cutting refers to the roughing feed or cuts the deep machining greatly, uses in the turning and the grinding generally.The force turning main characteristic is the lathe tool besides the main cutting edge, but also some is parallel in the work piece has processed superficial the vice-cutting edge simultaneously to participate in the cutting, therefore may enhance to feed quantity compared to the general turning several times of even several times.Compares with the high-speed cutting, the force cutting cutting temperature is low, the cutting tool life is long, the cutting efficiency is high; The shortcoming is processes the surface to be rough.When force cutting, the radial direction cutting force death of a parent is not suitable for to process the tall and slender work piece very much.
The vibration cutting is along the cutting tool direction of feed, the attachment low frequency or the high frequency vibration machining, may enhance the cutting efficiency.The low frequency vibration cutting has the very good chip breaking effect, but does not use the chip breaking equipment, makes the knife edge intensity to increase, time the cutting total power dissipation compared to has the chip breaking installment ordinary cutting to reduce about 40%.The high frequency vibration cutting also called the ultrasonic wave vibration cutting, is helpful in reduces between the cutting tool and the work piece friction, reduces the cutting temperature, reduces the cutting tool the coherence attrition, thus the enhancement cutting efficiency and the processing surface quality, the cutting tool life may enhance 40% approximately.
To lumber, plastic, rubber, glass, marble, granite and so on nonmetallic material machining, although is similar with the metal material cutting, but uses the cutting tool, the equipment and the cutting specifications and so on has the characteristic respectively.
The lumber product machining mainly carries in each kind of joiner's bench, its method mainly has: The saw cuts, digs cuts, the turning, the milling, drills truncates with the polishing and so on.
The plastic rigidity is worse than the metal, the easy bending strain, the thermoplastic thermal conductivity to be in particular bad, easy to elevate temperature the conditioning.When cutting plastic, suitably with the high-speed steel or the hard alloy tools, selects the small to feed quantity and the high cutting speed, and uses compressed air cooling.If the cutting tool is sharp, the angle is appropriate, may produce the belt-shaped scrap, easy to carry off the quantity of heat.
Glass (including semiconducting material and so on germanium, silicon) but degree of hardness high brittleness is big.To methods and so on glass machining commonly used cutting, drill hole, attrition and polishing.To thickness in three millimeters following glass plates, the simple cutting method is with the diamond or other hard materials, in glass surface manual scoring, the use scratch place stress concentration, then uses the hand to break off.
To the marble, the granite and the concrete and so on the hard material processing, mainly uses methods and so on cutting, turning, drill hole, shaping, attrition and polishing.When cutting the available circular saw blade adds the grinding compound and the water; The outer annulus and the end surface may use the negative rake the hard alloy lathe tool, by 10~30 meter/minute cutting speed turning; Drills a hole the available hard alloy drill bit; The big stone material plane available hard alloy planing tool or rolls cuts planing tool shaping; The precise smooth surface, available three mutually for the datum to the method which grinds, or the grinding and the polishing method obtains.
Cutting tool in hot strong alloy application
The aviation processing also changes rapidly. For example, nickel base heat-resisting alloy like several years ago the most people had not heard Rene88 now occupies to the aircraft engine manufacture uses the total metal quantity 10~25%. Has very good showing and the commercial reason regarding this. For example, these heat strong alloy will be able to increase the engine endurance moreover to permit the small engine work on the big airplane, that will enhance the combustion efficiency and reduces the operation cost. These tough good materials also present the expense on the cutting tool. Their thermal stability causes on the knife point the temperature to be higher, thus reduced the cutting tool life. Similarly, in these alloy carbide pellet remarkably increased the friction, thus reduces the cutting tool life.
As a result of changes in these conditions, can be very pleased to have processed many titanium alloys and nickel-based alloy materials C-2 hard metal alloys, in the application to today's cutting edge of blade to the crushing and cutting depth of the trench lines badly worn. But using the latest high-temperature processing of small particles hard metal alloys to be effective, cutlery life improved, but more importantly to enhance the reliability of applications in high-temperature alloys. Small particles hard metal than traditional hard metal materials higher compression strength and hardness, only a small increase in the resilience of the cost. And resulted in high temperature alloy processing than traditional hard metal resistance common failure mode more effective.
PVD (physical gas phase deposition) coating also by certificate effective processing heat-resisting alloy. TiN (titanium nitrides) the PVD coating was uses and still was most early most receives welcome. Recently, TiAlN (nitrogen calorization titanium) and TiCN (carbon titanium nitrides) the coating also could very good use. In the past the TiAlN coating application scope and TiN compared the limit to be more. But after the cutting speed enhances them is a very good choice, enhances the productivity in these applicati
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