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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。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)。幸運(yùn)地,有很多途徑闡述這些問題。簡(jiǎn)明的答案是當(dāng)?shù)镀?約占典型加工零件成本的 3%時(shí),冷卻液的成本(從購買到維護(hù)、儲(chǔ)存、處理)會(huì)占零件成本的 15%。問題是納米級(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。要談及的關(guān)于刀具微型制造的第一件事是它這里還沒有;第二件要說的事是它并不遙遠(yuǎn)。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。通常可以觀察到流出的冷卻液分散切屑,但壓力超過 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。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。 TiN(氮化鈦) PVD 涂層是最早使用的并仍然是最受歡迎的。這些韌性好的材料也把費(fèi)用呈現(xiàn)在刀具上。對(duì)玻璃的切削加工常用切割、鉆孔、研磨和拋光等方法。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。 磨削速度在 45 米/秒以上的切削稱為高速磨削。有些切削加工兼有刀尖軌跡法和成形刀具法的特點(diǎn),如螺紋車削。 涂層陶瓷也表現(xiàn)出能有效加工球墨鑄鐵。 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。這種耐磨性很大程度上受珠光體含量影響。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)相同感覺作出更快、更輕、更便宜的反應(yīng)。 The shorting is processes the surface to be 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 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 pared 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 joiner39。 The formed cutting tool law abbreviation forming, is with the formed cutting tool which 3 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 7039。 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 heatresisting 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 mercial 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 bustion 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 nickelbased alloy materials C2 hard metal alloys, in the application to today39。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。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。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。 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)來獲得的。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。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。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。例如,鎳基高溫合金如幾年前多數(shù)人未聽說過的 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%。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。 近來,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。 最近,已經(jīng)出現(xiàn)了一些有關(guān)這個(gè)專題揭示速度、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。例如,壓縮空氣被證明在很多應(yīng)用里排屑成為問題的場(chǎng)合有成功的反響。 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題一樣,需要從更寬的操作、環(huán)境和商業(yè)角度來評(píng)價(jià)。 。 刀具和納米技術(shù) 12 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。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。 金屬加工從業(yè)人員能很好理解有關(guān)冷卻液使用的問題,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)之外的干加工問題。因11 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)。 PVD(物理 氣相沉積)涂層也被證明有效加工高溫合金。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。 玻璃 (包括鍺、硅等半導(dǎo)體材料 )的硬度高而脆性大。 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。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。 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,來獲得工件所要求的表面幾何形狀,如車削外圓、刨削平面、磨削外圓、用靠模車削成形面等,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?;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)。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)。但同時(shí)球墨鑄鐵非常耐磨,有快速磨壞刀具材料的