【正文】 共 14 頁(yè) 第 14 頁(yè)第二篇：計(jì)算機(jī)英語(yǔ)論文翻譯畢業(yè)設(shè)計(jì)DATA WAREHOUSEData warehousing provides architectures and tools for business executives to systematically organize, understand, and use their data to make strategic large number of organizations have found that data warehouse systems are valuable tools in today39。陶瓷刀具特別脆，盡管目前已能進(jìn)行銑削，陶瓷刀具主要還是限于連續(xù)切削。因此，不降低刀具壽命就可得到較高的金屬切削率，或不改變金屬切削率而延長(zhǎng)刀具壽命。實(shí)驗(yàn)表明：高速鋼切削低碳鋼時(shí)，(350ft/min),就會(huì)很快失效，(150ft/min)時(shí)，就不能成功切削低碳鋼。下面討論最重要的幾種材料和它們對(duì)刀具設(shè)計(jì)的影響。角度7為側(cè)切削刃角，它是測(cè)切削刃和刀柄側(cè)面之間的夾角。為了節(jié)省磨刀時(shí)間，刀具段后刀面的一部分有時(shí)可以直接鍛造成形，而不需要進(jìn)行磨削。單尖刀具是指只有一個(gè)前刀面和一條連續(xù)切削刃的刀具。金屬切削刀具刀具的形狀（特別是其角度）和材料是刀具的兩個(gè)非常重要的因素。而絲杠產(chǎn)生的運(yùn)動(dòng)是通過(guò)滑板箱與絲杠之間的直接機(jī)械連接來(lái)實(shí)現(xiàn)的，對(duì)于螺母可以實(shí)現(xiàn)這種連接。通過(guò)轉(zhuǎn)動(dòng)溜板箱前的手輪，可以手動(dòng)操作拖板沿床身移動(dòng)。鎖定裝置可以使套筒在所需的位置上夾緊。大多數(shù)現(xiàn)代車(chē)床都裝置有5～15馬力的電動(dòng)機(jī)，為硬質(zhì)合金和金屬陶瓷合金刀具提供足夠的動(dòng)力，進(jìn)行高速切削。由于車(chē)床的精度在很大程度上取決于主軸，因此主軸的結(jié)構(gòu)尺寸較大，通常安裝在緊密配合的重型圓錐滾子軸承或球軸承中。導(dǎo)軌上的任何誤差，常常會(huì)使整個(gè)機(jī)床的精度遭到破壞。這位聰明的英國(guó)人還發(fā)明了一種把主軸和絲杠相連的變速裝置，這樣就可以切削螺紋。but the possibility of chatter promise must, as usual, be nose angle, number 8, is the angle between the two ponent cutting the corner is rounded off, the arc size is defined by the nose radius radius size influences finish and Tool MaterialsA large number of cutting tool materials have been developed to meet the demands of high共 14 頁(yè) 第 5 頁(yè)┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ 裝 ┊ ┊ ┊ ┊ ┊ 訂 ┊ ┊ ┊ ┊ ┊ 線 ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊畢業(yè)設(shè)計(jì)（論文）報(bào)告紙metalremoval most important of these materials and their influence on cutter design, are described Carbon , high carbon steel was the earliest cutting material used industrially, but it has now been almost entirely superseded since it starts to temper at about 220℃ and this irreversible softening process continues as temperature speeds with carbon steel tools are therefore limited to about (30ft/min)when cutting mild steel, and even at these speeds a copious supply of coolant is overe the low cutting speed restriction imposed by plain carbon steels, a range of alloy steels, known as highspeed steels, began to be introduced during the early years of this chemical position of these steels varies greatly, but they basically contain about % carbon and 4% chromium, with addition of tungsten, vanadium, molybdenum and cobalt in varying maintain their hardness at temperatures up to about 600℃, but soften rapidly at cutting speeds in excess of (350ft/min), and many cannot successfully cut mild steel faster than (150ft/min).Sintered cutting tools, which were developed in Germany in the late 1920s, usually consist of tungsten carbide or mixtures of tungsten carbide and titanium or tantalum carbide in powder form, sintered in a matrix of cobalt or of the paratively high cost of this tool material and its low rupture strength, it is normally produced in the form of tips which are either brazed to a steel shank or mechanically clamped in a specially designed clamped tool tips are frequently made as throwaway all the cutting edges have been used the inserts are discarded, ad regrinding would cost more than a new high hardness of carbide tools at elevated temperatures enables them to be used at much faster cutting speeds than highspeed steel(of 34m/s（600800ft/min）when cutting mild steel).They are manufactured in several grades, enabling them to be used for most machining earlier brittleness has been largely overe by the introduction of tougher grades, which are frequently used for interrupted cuts including many arduous facemilling , improvements have been claimed by using tungsten carbide tools coated with共 14 頁(yè) 第 6 頁(yè)┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ 裝 ┊ ┊ ┊ ┊ ┊ 訂 ┊ ┊ ┊ ┊ ┊ 線 ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊畢業(yè)設(shè)計(jì)（論文）報(bào)告紙titanium carbide or titanium nitride(about coating thickness).These tools are more resistant to wear than conventional tungsten carbide tools, and the reduction in interface friction using titanium nitride results in a reduction in cutting forces and in tool , higher metal removal rates are possible without detriment to tool life or alternatively longer tool lives could be achieved at unchanged metal removal uses of other forms of coating with aluminum oxide and polycrystalline cubic boron nitride are still in an experimental stage, but it is likely that they will have important applications when machining cast iron, hardened steels and high melting point socalled ceramic group of cutting tools represents the most recent development in cutting tool consist mainly of sintered oxides, usually aluminum oxide, and are almost invariably in the form of clamped of the parative cheapness of ceramic tips and the difficulty of grinding them without causing thermal cracking, they are made as throwaway tools are a postwar introduction and are mot yet in general factory most likely application is in cutting metal at very high speeds, beyond the limits possible with carbide resist the formation of a builtup edge and in consequence produce good surface the present generation of machine tools is designed with only sufficient power to exploit carbide tooling, it is likely that, for the time being, ceramics will be restricted to highspeed finish machining where is sufficient power available for the light cuts extreme brittleness of ceramic tools has largely limited their use to continuous cuts, although their use in milling is now they are poorer conductors of heat than carbides, temperatures at the rake face are higher than in carbide tools, although the friction force is usually strengthen the cutting edge, and consequently improve the life of the ceramic tool, a small chamfer or radius is often stoned on the cutting edge, although this increases the power producing very fine finishes of （23um)on nonferrous metals such as copper and aluminum, diamond tools are often diamond is brazed to a steel turning and boring are essentially finishing operations, as the forces imposed by any but the smallest cuts cause the diamond to fracture or be torn from its 共 14 頁(yè) 第 7 頁(yè)┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ 裝 ┊ ┊ ┊ ┊ ┊ 訂 ┊ ┊ ┊ ┊ ┊ 線 ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊畢業(yè)設(shè)計(jì)（論文）報(bào)告紙suitable conditions diamonds have exceptiona