【正文】 owered movement to the carriage and cross slide, a rotating feed rod is feed rod, which contains a keyway throughout most of its length, passes through the two reversing bevel pinions and is keyed to pinion can be brought into mesh with a mating bevel gear by means of the reversing lever on the front of the apron and thus provide “forward” or “reverse” power to the clutches connect either the rack pinion or the crossslide screw to provide longitudinal motion of the carriage or transverse motion of cross cutting threads, a second means of longitudinal drive is provided by a lead motion of the carriage when driven by the feedrod mechanism takes place through a friction clutch in which slippage is possible, motion through the lead screw is by a direct, mechanical connection between the apron and the lead is achieved by a split means of a clamping lever on the front of the apron, the split nut can be closed around the lead the split nut closed, the carriage is moved along the lead screw by direct drive without possibility of 14 頁(yè) 第 3 頁(yè)┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ 裝 ┊ ┊ ┊ ┊ ┊ 訂 ┊ ┊ ┊ ┊ ┊ 線(xiàn) ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊畢業(yè)設(shè)計(jì)（論文）報(bào)告紙Modern lathes 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(xiàn) ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊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(yè) 第 5 頁(yè)┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ 裝 ┊ ┊ ┊ ┊ ┊ 訂 ┊ ┊ ┊ ┊ ┊ 線(xiàn) ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊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 abou