【正文】 have a quickchange gear input end of this gear box is driven from the lathe spindle by means of suitable output end of the gear box is connected to the feed rod and lead , through this gear train, leading from the spindle to the quickchange gear box, thence to the lead screw and feed rod, and then to the carriage, the cutting tool can be made to move a specific distance, either longitudinally or transversely, for each revolution of the typical lathe provides, through the feed rod, fortyeight feeds ranging from inch to inch per revolution of the spindle, and, through the lead screw, leads for cutting fortyeight different threads from to 92 per some older and some cheaper lathes, one or two gears in the gear train between the spindle and the change gear box must be changed in order to obtain a full range of threads and TOOLShape of cutting tools, particularly the angles, and tool material are very important purpose of this unit is to introduce the cutting tool geometry and tool Tool GeometryAngles determine greatly not only tool life but finish quality as principles upon which cutting tool angles are based do not depend on the particular , grinding wheel are being , however, the lathe(turning)tool, depicted in , might be easiest to visualize, its geometry is features have been identified by many technical literature is full of confusing in the attempt to clear up existing disorganized conceptions and nomenclature, the American Society of Mechanical Engineers published ASA Standard follows is based on singlepoint tool is a cutting tool having one face and one continuous cutting angles identified in are as follows:(1)Backrake angle,(2)Siderake angle,(3)Endrelief angle(4)Endrelief angle(5)Siderelief angle(6)Endcuttingedge angle,(7)Sidecuttingedge angle,(8)Nose angle,(9)Nose angle 1, on front view, is the backrake is the angle between the tool face and a line parallel to the base of the shank 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(yè) 第 4 頁(yè)┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ 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。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 w