【正文】 hank in a longitudinal plane perpendicular to the tool this angle is downward from front to rear of the cutting edge, the rake id positive。when upward共 14 頁 第 4 頁┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ 裝 ┊ ┊ ┊ ┊ ┊ 訂 ┊ ┊ ┊ ┊ ┊ 線 ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊畢業(yè)設(shè)計(jì)（論文）報(bào)告紙from front to back, the rake is angle is most significant in the machining process, because it directly affects the cutting force, finish, and tool siderake angle, numbered 2, measures the slope of the face in a cross plane perpendicular to the tool , also, is an important angle, because it directs chip flow to the side of the tool post and permits the tool to feed more easily into the endrelief angle is measured between a line perpendicular to the base and the end flank immediately below the end cutting edge。it is numbered 3 in the provides clearance between work and tool so that its cut surface can flow by with minimum rubbing against the save time, a portion of the end flank of the tool may sometimes be left unground, having been previously forged to such case, this endclearance angle, numbered 4, measured to the end flank surface below the ground portion, would be larger than the relief the end cutting edge is oblique to the relief angle is then best measured in a plane normal to the end cutting edge perpendicular to the base of the clearance permits the tool to advance more smoothly into the siderelief angle, indicated as 5, is measured between the side flank, just below the cutting edge, and a line through the cutting edge perpendicular to the base of the clearance permits the tool to advance more smoothly into the 6 is the endcuttingedge angle measured between the end cutting edge and a line perpendicular to the side of the tool angle prevents rubbing of the cut surface and permits longer tool sidecuttingedge angle, numbered 7, is the angle between the side cutting edge and the side of the tool true length of cut is along this the angle determines the distribution of the cutting greater the angle, the longer the tool life。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 第 5 頁┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ 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 第 6 頁┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ 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 g