机械专业英语1-2[81P][2.44MB](2)

Special English for Mechanical Engineering 机电教研室：张晓 扩展学生在本专业方面的英语词汇量 熟悉本领域的专业术语 了解科技英语的表达特点及掌握专业英语翻译技巧 能阅读本专业的外文资料，并具备一定的写作能力 温馨推荐 您可前往百度文库小程序 享受更优阅读体验 不去了 立即体验 机械工程专业英语的特点 1.专业英语词汇特点：专业术语多，合成新词多，前后缀出现频率高，缩略词经常出现，非限定动词（尤其是分词）使用频繁，词义单一。 2.专业英语语法特点：常用形式主语和形式宾语、名词结构和被动语态使用频繁，复杂长句多，复合句多，每句包含的信息量大。 3.专业英语的修辞特点：时态运用有限，修辞手法简单，逻辑语法使用普遍。 机械工程专业英语的特点(1) 专业性词汇较多，且词形复杂，记忆难度大。 chrome-moly steel —铬钼钢 antifriction bearing—滚动轴承 epicyclic gear—行星齿轮 (2)有些单词虽词形与基础英语相同，但词义相差很大 pig-iron —生铁 bearing —轴承（方向，生育，忍耐） bolt —螺栓（闪电，闩） (3)专业合成词较多，且与各原单词的含义有一定的不同 slide-crank mechanism —曲柄滑块机构 detail drawing —零件图 four-bar linkage —四连杆机构 机械工程专业英语的特点(1)由于机械电子工程英语主要论及一些客观存在的事物，很少 论及人，因此被动语态用的特别多，比比皆是。例如： A mechanism has been defined as ―a combination of rigid or resistant bodies so formed and connected that they move upon each other with definite relative motion.‖ 机构被定义为：―是由刚体或者有承载能力的物体联接而形成的组合体，它们在运动时彼此之间应该有确定的相对运动‖ 机械工程专业英语的特点(2)机电专业英语由于要表述较复杂的概念，因此句子结构具有 句子长、定语从句多、名词化结构多，非限定性谓语结构、倒装、省略、分隔结构随处可见，常出现句子套句子的情况，给阅读理解上带来了极大的困难。比如： It i s m uch b etter f or d esign e ngineers t o d o a c omplete j ob o f analysis,selection,and specification at the material development stage of design rather than to leave it to t he production-design s tage, w here c hanges m ay b e m ade b yothers, possibly l ess k nowledgeable a bout a ll o f t he f unction a spectsof the p roduct. 机械工程专业英语的特点It i s m uch b etter f or d esign e ngineers t o d o a c ompletejob of material analysis,selection,and specification at the development stage of design rather than to leave it to t he production-design s tage, w here c hanges m ay b e m ade b yothers, possibly l ess k nowledgeable a bout a ll o f t he f unction a spectsof the p roduct. 择和确定工作，而不是将其留到生产设计阶段，因为在生产设计阶段 材料 关于××同志的政审材料调查表环保先进个人材料国家普通话测试材料农民专业合作社注销四查四问剖析材料 的更换是由其他人员进行的，这些人对产品的所有功能的了解可能不如设计工程师。 ?We made a hole in a cork and pushed it into a narrow glass tube. Then we pushed this into the neck of a bottle which we had filled with colored water. When we did this, some of the colored water went up into the tube. We marked the level of the colored water in the tube. Then weput the bottle into a pan of hot water. ?After a hole was made in a cork,a narrow glass tube was inserted and the cork was inserted into the neck of a bottle filled with colored water.On doing this,some of the colored water rose the tube. The level of the colored water in the tube was marked. Then the bottle was placed into a pan of hot water. Ordinary English 通俗化：常用词汇用得多 多义性：一词多义，使用范围广人称化：人称丰富，形式多样多时性：描述生活，时态多样主动性：句子倾向于用主动态简单性：单句、散句用的多 口语化：口语用得多，随意灵活 Scientific English 专业化：专业术语用得多 单义性：词义相对单一，因专业而不同物称化：多用物称，以示客观 现时性：叙述事实多用现在时 被动性：句子倾向于用被动 复杂性：复杂单句用得多，复合句用得多 书 关于书的成语关于读书的排比句社区图书漂流公约怎么写关于读书的小报汉书pdf 面化：长句用得多，书卷气浓 Course Content C onventional Machining Processes N ontraditional Machining Processes T olerance and Fits L ocation and Fixtures G ear Transmission C NC Machining Centers Automatic Control T ransducers Unit5 Conventional Machining Processes Can you give me a list of machining processes? Turing Boring Milling Drilling Grinding Planning … 车削、镗削、铣削、钻削、磨削、刨削… Unit5 Conventional Machining Processes 5.1 I ntroduction Conventional m achining i s t he g roup o f m achining o perations that u se s ingle- o r m ulti-point t ools t o r emove m aterial i n t he f orm of chips.Metal cutting involves removing metal through machining operations.Machining traditionally takes place on lathes, d rill p resses, a nd m illing m achines w ith t he u se o f v arious cutting t ools. M ost m achining h as v ery l ow s et-up c ost c ompared forming,molding,and casting processes.However, with machining i s m uch m ore e xpensive f or h igh v olumes. M achining is necessary where tight tolerances on dimensions and finishes are r equired. Unit5 Conventional Machining Processes 5.1译文 传统机械加工是一组利用单刃或者多刃刀具以切屑形式去除材料的加工方式。金属切削意味着通过机械加工去除金属。传统的机械加工都是利用不同的刀具在车床、钻床和铣床上进行的。与成型加工、锻压和铸造工艺相比，大多数机械加工的生产准备成本都较低，然而如果是大批量生产，其成本要高得多。当对零件的尺寸公差和光洁度要求较高时，机械加工是很有必要的。 Unit5 Conventional Machining Processes 5.2 T urning a nd L athe Turning i s o ne o f t he m ost c ommon o f m etal c uttingoperations. In turning,a workpiece is rotated about its axis as s ingle-point cutting tools are fed into it,shearing away excess material a nd creating t he d esired c ylindrical s urface. T urning c an o ccur o nboth external a nd i nternal s urfaces t o p roduce a n axially-symmetrical contoured p art. P arts r anging f rom p ocket w atch c omponentsto large d iameter m arine p ropeller s hafts c an b e t urned o n a l athe. Apart from turning,several other operations can also be performed o n l athe. marine propeller Unit5 Conventional Machining Processes axially ['?ksi?li] adv.轴向地 symmetrical [si'metrik?l] a. 对称的 cylindrical [si'lindrikl] a.圆柱形的 contoured ['k?ntu?d] a.显示轮廓的，与某种形体轮廓相吻合的译文: 在金属切削加工操作中，车削是最常见的一种。在车削过程中，工件绕其轴线回转，单刃车刀沿工件进给，切除掉多余的材料，最后形成要求的圆柱形表面。车削可以加工外面和内表面以形成具有轴对称的成形工件。从怀表的零件到大直径的船用螺旋桨轴都可以在车床上加工。 除了车削，还有另外几种加工操作都可以在车床上进行。 5.2 Turning and Lathe Boring and internal turning.Boring and internal turning a re performed on the internal surfaces by a boring bar or s uitable internal cutting tools.If the initial workpiece is solid,a d rilling operation m ust b e p erformed f irst. T he d rilling t ool i s h eld i nthe tailstock, a nd t he latter i s t hen f ed a gainst the workpiece. W hen boring i s d one i n a l athe, t he w ork u sually i s h eld i n a c huck o ron a f ace p late. H oles m ay b e b ored s traight, t apered, o r t oirregular contours. B oring i s e ssentially i nternal t urning w hile f eeding t he tool p arallel t o t he r otation a xis o f t he w orkpiece. 5.2 Turning and Lathe tailstock ['teilst?k] n. 尾座 chuck [t??k] n.卡盘，夹头 译文: 利用镗杆或合适的内圆车刀可以进行镗削和车内圆。如果工件毛坯是实心的，首先要钻孔。钻头安装在尾架上，后者向工件进给。如果在车床上进行镗削加工，工件通常装夹在卡盘或者花盘上。镗出的孔可以是直孔、锥孔或者不规则轮廓。当将刀具沿工件的回转轴线平行进给时，镗削实际上就是车内圆。 5.2 Turning and Lathe Facing. F acing i s t he p roducing o f a f lat s urface a s t he r esult o fa tool‘s b eing f ed a cross t he e nd o f t he r otating w orkpiece. U nless the w ork i s h eld o n a m andrel, i f b oth e nds o f t he w ork a re t obe faced, i t must b e turned a round after t he f irst end i s c ompleted and t hen t he f acing o peration r epeated. T he c utting s peedshould be d etermined f rom t he l argest d iameter o f t he s urface t o b e f aced. Facing m ay b e d one e ither f rom t he o utside i nward or f romthe center o utward. I n e ither c ase, t he p oint o f the t ool must b e s et exactly a t t he h eight o f c enter o f r otation. 5.2 Turning and Lathe c lamp c arriage I n t he f acing o f c asting o rother materials t hat h ave a h ard s urface, t he d epth o f t he f irst c utshould be s ufficient t o p enetrate t he h ard material t o a void e xcessive tool wear. mandrel ['m?ndr?l] n.车床心轴 clamp [kl?mp] v. 夹紧，夹住 carriage [?k?rid?] n.大刀架，拖板 penetrate ['penitreit] v. 穿透，渗透 tool wear 刀具磨损 5.2 Turning and Lathe 译文: 车端面可以加工出一个平面，它是当车刀沿回转工件的端面横向进给的结果。除非工件固定在心轴上，如果工件两端都要车端面，必须将一端加工完成后，将工件调头，重复进行车端面加工。车削速度必须由所加工表面的最大直径来决定。车端面可以由外向内也可以由中心向外进行。无论哪种情况，刀尖必须准确地与回转中心对正。由于切削力有将车刀推离工件的趋势，通常 行车端面加工时，首次切深要足以穿透硬质材料从而避免过度的刀具磨损。 5.2 Turning and Lathe Parting.Parting is the operation by which one section of a workpiece i s s evered f rom t he r emainder b y m eans o f c utofftool. Because cutting tools a re q uite thin and m ust have c onsiderable overhang, t his p rocess i s l ess a ccurate a nd m ore d ifficult. T hetool should b e s et e xactly a t t he h eight o f a xis o f r otation, b e k eptsharp, have p roper c learance a ngles, a nd b e f ed i nto t he w orkpiece a ta proper a nd u niform f eed r ate. remainder [ri'meind?]剩余物，余数 overhang ['?uv?'h??] vt.悬于...之上n.伸出；突出 uniform ['ju:nif?:m] a.相同的，一致的n.制服；军服 clearance angles 后角 5.2 Turning and Lathe 译文: 切断是一种利用切断刀（割刀）将工件的一部分与其剩余部分脱离的加工方法。由于切断刀非常薄而且处于悬臂状态，因此这种加工方法不太精确而且加工起来常常比较困难。切断刀必须准确地对正回转轴，保持锋利，具有合适的后角，以合适、不变的进给率沿工件进给。 5.2 Turning and Lathe Threading. T hreading c an b e c onsidered a s t urning s ince t hepath to be travelled by the cutting tool is helical.However,there a re some m ajor d ifferences b etween t urning a nd t hreading. W hilein turning, t he i nterest i s i n g enerating a s mooth c ylindricalsurface, in t hreading t he i nterest i s i n c utting a h elical t hread o f a g iven form a nd d epth w hich c an b e c alculated f rom t he f ormulae. [?helik?l] a.螺旋状的 译文: 车螺纹可以看作是车削，只是车刀所形成的加工轨迹是螺旋线。但二者也存在一些不同之处。车削主要考虑能否生成光滑的圆柱形表面，而车螺纹注重的是能否切出具有按公式计算出来的 规定 关于下班后关闭电源的规定党章中关于入党时间的规定公务员考核规定下载规定办法文件下载宁波关于闷顶的规定 形状和深度的螺旋线。 5.2 Turning and Lathe There are two basic requirements for thread cutting. ?An accurately shaped and properly mounted tool is neededbecause thread cutting is a form-cutting operation.The resulting thread profile is determined by the shape of the tool and its positionrelative to the workpiece. ?The second by requirement is that the tool must move longitudinally in a specific relationship to the rotation of workpiece, becausethis determines the lead of the thread. This requirement is metthrough the use of the lead screw and the split unit, which providepositive motion of carriage relative to the rotation of spindle. form-cutting o peration 成形加工 longitudinally [l?:?d?i'tju:din?li] a dv.纵向 lead screw 丝杠 split unit 开合机构 5.2 Turning and Lathe 译文: 车螺纹有两个基本要求：首先，由于车螺纹是一种成形加工，因此车刀必须具有准确的形状而且要安装合适。所切出的螺纹外形是由车刀形状和它与工件的相对位置决定的。其次，车刀的纵向进给与工件的回转运动具有特定的关系，因此这决定了螺纹的导程。这个条件可以通过采用丝杠和开合机构得到满足，它们可以实现拖板相对于主轴回转运动的精确可靠的运动。 5.2 Turning and Lathe Lathe.Many types of lathes are used for production t urning. According t o p urposes a nd c onstruction, l athe-type m achinetools can b e c lassified a s f ollow: 1. E ngine l athes 普通车床 2. V ertical l athes 立式车床 3. T urret l athes 转塔车床 4. S ingle-or m ultiple-spindle a utomatic o r s emi-automatic l athes 5. C ontouring l athes 仿形车床 6. U niversal l athes 万能车床 7. Special-purpose lathes such as crankshaft lathes, camshaft lathes, car wheel lathes and backing-off lathes, etc. 1 6 7 11 2 10 3 9 4 8 5 5.2 Turning and Lathe Lathe b ed i s f oundation o f t he e ngine l athe, w hich i s h eavy,rugged casting m ade t o s upport t he w orking p arts o f t he l athe. T he s ize and mass of the bed gives the rigidity necessary for a ccurate engineering t olerances r equired i n m anufacturing. O n t op o f t he bed a re m achined s lideways t hat g uide a nd a lign t he c arriageand tailstock, a s t hey a re m ove f rom o ne e nd o f t he l athe t o t he o ther. ? ? ? 床身是普通车床的基础，它是由沉重而坚固的铸件制作而成的，其目的是为了支撑车床的工作部件。床身的尺寸和质量要使车床具有足够的刚性以保证制造过程中获得所需的工程公差。床身上的导轨可以引导和对准拖板和尾座，使它们可以从车床的一端移动到另一端。 5.2 Turning and Lathe ?Headstock i s c lamped a top t he b ed a t l eft-hand e nd o f t he l athe and c ontains t he m otor t hat d rives t he s pindle w hose a xis i s parallel to the guideways through a series of gears housed within t he g earbox. T he f unction o f g earbox i s t o g enerate a number o f d ifferent s pindle s peeds. ?atop a dv. 在(…)顶上 ?gearbox 齿轮箱 床头箱（主轴箱）紧固在床身上面的左端，内装有电机，它通过变速箱内的一组齿轮来驱动主轴转动，主轴的轴线平行于导轨。变速箱的功能是可以产生不同的主轴转速。 5.2 Turning and Lathe ?o n t he r ear o f change gears l ead s crew feed r od ?on the rear of 在…的尾部 ?change gears 挂轮 ?lead screw 丝杠 ?feed rod 光杠 主轴齿轮安装在主轴的尾部，通过挂轮把动力传递到进给箱，如果是车螺纹，进给箱将动力分配到丝杠上；如果是车削，就将动力分配到光杠上。 5.2 Turning and Lathe ?The spindle has a through hole extending lengthwise t hrough which b ar s tocks c an b e f ed i f c ontinuous production i s u sed. The hole can hold a plain lathe center by its tapered i nner surface a nd m ount a c huck, a f ace p late o r c ollet b y i tsthreaded outer s urface. ? ? 主轴有一个纵向通孔，如果连续加工棒料，通孔就用来实现棒料的送料。这个通孔具有一个内锥面，可以安装普通车床的中心顶尖。主轴的外表面车有螺纹，可以安装卡盘，花盘或夹头。 5.2 Turning and Lathe Carriage a ssembly i s a ctually a n H-shaped b lock t hat s its a cross the g uideways a nd i n f ront o f l athe b ed. T he f unction o f t he carriage i s t o c arry a nd m ove t he c utting t ool l ongitudinally. I t can b e m oved b y h and o r b y p ower a nd c an b e c lamped i nto position with a l ocking nut.The carriage is c omposed of the cross s lide, c ompound r est, t ool s addle, a nd a pron. 5.2 Turning and Lathe 纵向移动装夹车刀 横向移动 纵向移动 变换箱外手柄位置，在光杠或 丝杠的传动下，可使车刀按要 求方向作进给运动 5.2 Turning and Lathe ?The c ross s lide i s m ounted o n t he d ovetail g uideways o n t he t op of t he s addle a nd i t m oved b ack a nd f orth a t 90°to t he a xis o f the l athe b y t he c ross s lide l ead s crew. T he l ead s crew c an b e hand o r p ower a ctivated. ? 横拖板安装在刀架鞍板上部的燕尾槽导轨上。它利用横拖板丝杠于车床轴线成90度夹角的方向上前后移动。丝杠可以手动或者自动驱动。 5.2 Turning and Lathe ?The compound rest is mounted on the cross slide and can b e swiveled a nd c lamped a t any a ngle in a h orizontal plane. T he compound i s t ypically u sed f or c utting c hamfers o r t apers,but must a lso b e u sed w hen c utting t hread. T he c ompound r estcan only b e f ed b y h and. T here i s n o p ower t o c ompound r est.The cutting t ool a nd t ool h older a re s ecured i n t he t ool p ost w hichis mounted d irectly t o t he c ompound r est. ?swivel ['sw?v?l] v 5.2 Turning and Lathe The t ool s addle i s a n H s haped c asting m ounted o n t he t op o fthe guideways a nd h ouses t he c ross s lide a nd c ompound r est. I tmakes possible l ongitudinal, c ross a nd a ngular f eeding o f t he t ool b it. ?刀架鞍板是一个安装在导轨上部的H形铸件，容纳有横拖板和小刀架。它可以实现刀尖的纵向、横向和斜向进给。 5.2 Turning and Lathe The a pron i s a ttached t o t he f ront o f t he c arriage a nd c ontainsthe gears a nd f eed c lutches w hich t ransmit m otion f rom t he f eedrod or lead screw to carriage and cross slide.When cutting s crew threads, p ower i s p rovided t o t he g earbox o f t he a pron b y t helead screw. I n a ll o ther t urning o perations, i t i s t he f eed r od t hatdrives the c arriage. 5.2 Turning and Lathe ?Tailstock i s c omposed o f a l ow b ase a nd t he m ovable p art o f the tail-stock proper, t he transverse adjustments being made with a cross screw furnished with a square head.The two parts a re h old t ogether b y t he h olding-down b olts w hich s ecure the t ailstock t o t he b ed. ? ? ?尾座由底座和尾座体的可移动部件组成。课移动部件的横向调整有带有四方头的横向丝杠来完成。底座和可移动部分通过压紧螺栓连接在一起并将尾座固定在床身上。 5.2 Turning and Lathe ?The t ailstock i s l ocated o n t he o pposite e nd o f t he l athe f rom the headstock.It supports one end of the work when machining b etween centers,supports long p ieces held i n the chuck, a nd h olds v arious f orms o f c utting t ools, s uch a s d rills, reamers, a nd t aps. ? ? ?尾座位于机床上和主轴箱相反的另一端。当采用两端顶尖加工时，尾座支撑工件的一端，以支撑在卡盘中的长形零件。另外尾座还可以夹持各种刀具，如钻头、铰刀和丝锥等。 Milling is the process of cutting away material by feeding a workpiece past a rotating multiple tooth cutter. ?Peripheral M illing ?Face M illing ?End M illing ?vertical m illing machine ?horizontal m illing machine ?Column ?Knee ?Saddle ?Worktable ?Head ?Overarm 端铣 顺铣 铣 削 方 式 Peripheral Milling End Milling 周铣 逆铣 1. P eripheral Milling –The milled face is generated by teeth located on periphery of the cutter body. The axis of cutter rotation is generally in a plane parallel to the workpiece surface to be machined (shown in Fig.5.2a). 2. F ace Milling –The cutter is mounted on a spindle have an axis of rotation perpendicular t o the workpiece surface. 3. E nd Milling peripheral [p??rif?r?l] a.圆周的；外面的；次要的 Head Overarm ? 升降台 Worktable ? 工作台 ? 主轴头 Saddle Knee THE BASIC COMPONENTS: ? 立柱 Column ? 横梁 Base ? 床鞍 Column ?An oil reservoir and pump in the column keep the s pindle lubricated. r ests o n ?reservoir n.油箱，容器； ?lubricate vt. 使滑润 ?coolant n.冷却剂，冷却液 ?rest on 被支撑在；依赖，依据 Knee ?The feed change gearing i s enclosed within the knee. ?The levercan be raised or lowered either by hand or power feed. ? ? ?升降台里有可以改变进给量的齿轮传动机构。 ?操作杆向上或向下以实现手动或自动进给。 ?Saddle supports the table and can move transversely, w hich slides o n a h orizontal d ovetail, p arallel t o t he a xis o f t hespindle, on the knee.The swivel table(on universal machines only) i s attached to the saddle and can be swiveled approximately 45°in e ither d irection. ? ? ?Power feed mechanism is contained in the knee and controls the longitudinal, transverse (in and out) and vertical feeds. ?On s ome u niversal k nee a nd c olumn m illing m achines t hefeed is obtained by turning the speed selection handle until t he desired r ate o f f eed i s i ndicated on t he f eed d ial. ?[?dai?l] ?动力进给机构位于升降台内部，控制纵向、横向及垂直进给。?在有些升降台立式万能铣床中，通过旋转转速选择手柄直到所需的进给速率与进给刻度盘上的标记对齐，就可以获得所需的进给量。 ?The worktable can be moved longitudinally with respect to t he saddle by hand or by power.?Place the end of the directional feed control lever to the left to feed the table to the left. – – ?Head contains the spindle and cutter holder.In vertical machines t he h ead m ay b e f ixed o r v ertically a djustable. ?The front of the spindle,which is near the table,has an internal t aper m achined o n i t. T he i nternal t aper (3 ?i nches per f oot)permits mounting tapered-shank cutter holders and cutter arbor.Two keys,located on the face of the spindle, provide a p ositive d rive f or t he c utter h older, o r a rbor. ?Overarm i s t he h orizontal b eam t o w hich t he a rbor s upport i s fastened. T he o verarm m ay b e s ingle c asting t hat s lides i nthe dovetail g uideways o n t he t op o f t he c olumn. I t m ay c onsistof one or t wo cylindrical bars that slide through the hole in t he column. ?横梁是一个水平的梁，用以固定刀杆支架。横梁有可能是一个铸件，它可以沿着立柱上部的燕尾槽导轨滑动。它可能由一根或两根圆柱构成，穿过立柱上的孔进行滑动。 ?On s ome m achines t o p osition t he o verarm, f irst u nclamp t he locknuts a nd t hen e xtend t he o verarm b y t urning a c rank. O n others,the overarm is moved by merely pushing on it. To place the arbor supports on an overarm,extend one of the bars a pproximately 1-inch f arther t han t he o ther b ar. 5.4 Drilling and Drill Press ? ? –Drilling –Reaming –Tapping –Counterboring –Countersinking –Spotfacing –Boring ? –Sensitive bench type –Upright type –Radial type –Special purpose type 5.4 Drilling and Drill Press ?Definition of drill –Drill can be defined as a rotary end cutting tool having one or more cutting lips, and h aving one or more helical o r straight flutes f or passage of chips and the admission of a cutting fluid. ? ? ?钻头可以定义为具有一个或者多个切削刃的回转刀具，它的一个或多个螺旋排屑槽或直排屑槽起到作为切屑排除通道和容纳切削液的作用。 Drilling; Reaming; Tapping; Counterboring; Countersinking; Spotfacing; Boring 钻孔、铰孔、攻丝、平底锪孔、锥底锪孔、锪孔口平面、镗孔 5.4 Drilling and Drill Press Drilling ?Drilling i nvolves s electing t he p roper t wist d rill o r c utter f orthe job, p roperly i nstalling t he d rill i nto t he m achine s pindle,setting the s peed a nd f eed, d rilling a s maller p ilot h ole, a nd d rillingthe hole to specifications within the prescribed tolerance. D rilled holes are always slightly oversized,or s lightly l arger t han t he diameter o f t he d rill‘s o riginal d esignation. 5.4 Drilling and Drill Press Reaming ?It is difficult,if not impossible,to drill a hole to an e xact standard d iameter. W hen g reat a ccuracy i s r equired, t heholes are f ist d rilled s lightly u ndersized a nd t hen r eamed t o s ize. ?When y ou m ust d rill a nd r eam a h ole, i t i s b est i f t he s etup i snot changed. ?把孔钻削到准确的 标准 excel标准偏差excel标准偏差函数exl标准差函数国标检验抽样标准表免费下载红头文件格式标准下载 直径，即使并非不可能，那也是非常困难的。当精度要求很高时，可以先钻一个小孔，然后通 过铰削将孔加工到规定尺寸。 ?当你必须先钻孔再铰孔时，工件最好是一次装卡。 5.4 Drilling and Drill Press Tapping i s c utting a t hread i n a d rilled h ole. 5.4 Drilling and Drill Press Counterboring ?Counterboring i s t he p rocess o f u sing a c ounterbore t oenlarge the upper of a hole to a predetermined depth. C ountebored holes are p rimarily used t o r ecess socket head c ap s crews a nd similar b olt h eads s lightly b elow t he s urface. ? ? 5.4 Drilling and Drill Press Countersinking ?Countersinking is an operation in which a cone-shaped enlargement i s c ut a t t he t op o f a h ole t o f orm a r ecessbelow the surface.A conical cutting tool is used to produce this chamfer.When countersinking,the cutter must be p roperly aligned with the existing hole.Countersinking is useful in removing burrs from edges of the holes,as well as accommodating t he c ountersunk s crew h ead. ?cone-shaped adj.锥形的 ?conical adj.圆锥形的 ?chamfer n.斜面、倒角、凹槽 ?burr n.毛刺 ?countersunk n.沉头孔、埋头孔 5.4 Drilling and Drill Countersinking ? Countersinking is an operation in which a cone-shaped enlargement i s c ut a t t he t op o f a h ole t o f orm a r ecessbelow the surface. A conical cutting tool is used to produce this chamfer. When countersinking, the cutter must be p roperly aligned with the existing hole. Countersinking is useful in removing accommodating t he c ountersunk s crew h ead. – Press burrs from edges of the holes, as well as 5.4 Drilling and Drill Press Spotfacing ?Spotfacing is the smoothing off and squaring of a rough o r curved s urface a round a h ole t o p ermit l evel s eating o fwashers, nuts, o r b olt h eads. ?When r ough s urface, c astings, a nd c urved s urfaces a re n ot a t the r ight a ngles t o t he c utting t ool, g reat s train m ay o ccur o nthe pilot h ole a nd c ounterbore, w hich c an l ead t o b roken t ools. 5.4 Drilling and Drill Press Boring ?Boring i s c onducted w hen a s traight a nd s mooth h ole i sneeded occasionally w hich i s t oo l arge o r o dd s ized f or d rills o r r eams. ?To bore a ccurately, t he s etup m ust b e r igid, m achine m ust b e sturdy, a nd p ower f eed m ust b e u sed. ?odd s ized ?sturdy['st?:di] ?有时所加工的光滑直孔的直径太大或者不是标准系列尺寸，无法匹配钻头或铰刀时，就需要进行镗孔加工。 ?为了使镗孔加工精度高，装夹必须刚性好，机床必须牢固，而且必须采用自动进给。 5.4 Drilling and Drill ?Types of drill press –Sensitive bench type –Upright type –Radial type –Special purpose type 台钻Press 立式钻床摇臂钻床（汽车半轴）专用钻床 5.4 Drilling and Drill Press Head Base Quill assembly Chuck Table Base Table Column Column Head Chuck Quill Assembly Construction Features of Sensitive Drilling Machine Base Column Chuck Table Speeds on a stepped V pulley drive are changed by Head the head. The quill moves vertically by means of a rack and pinion. Quill Located on the lower end of the spindle is either a Morse Assembly mounted. It is heavy gray iron or ductile iron casting with slots to support and hold work that is too large for the table. The outer surface is machined to function as a precision way of aligning the spindle with table. Chuck is used to clamp and fix the drill through a cone surface locking mechanism. Most worktables have slots and holes for mounting vises and other workholding accessories. changing the position of the V-belt. Speeds on a variable- speed drive mechanism are changed by a hand wheel on taped hole or a threaded stub where the drill chuck is 英语谜语或脑筋急转弯（Riddles） Q: Why did the man throw the butter o ut the window? A: He wanted to see the butterfly. Q: A man rode into town on Tuesday. Two days later he rode home on Tuesday. How is this possible? A: His horse's name is Tuesday. 英语谜语或脑筋急转弯（Riddles）Q: W hat is black when it is clean and white when it is dirty? A: A blackboard Q: What is "four feet on four feet waiting for four feet? A: A cat on a chair waiting for a mouse Q: Which three letters can frighten a thief away? A: I C U Q: What will you break once you say it ? A: Silence Q: What always goes up and never goes down? A: Your age Q: Why did the boy make his dog sit in the sun? A: He wants to have a hot dog. Q: Which is faster, heat or cold? A: Heat, because you can catch a cold