机械制造工艺学双语课件

1、精品 料推荐制造技术基础复习基本概念、基本原理英语表达参考review the basic concepts and principles of fundamentals of manufacturing technologyin englishchapter one design for mechanical process planning section 1 basic concepts? production procedure of mechanical products? process procedure of machiningelements of process proce

2、dure of machining1 sequence 工序； 2 installation 安装； 3 station 工位； 4 step 工步； 5 pass走刀? sequence: process procedure that consists of several sequencesduring which workers operate on the works continuously in the same place; (操作者、加工地、工作对象 人为划分，相对可变 )? installation: in a sequence if the work is required

3、 to put into position and clamp several times,the part of sequence done in one positioning and clamping is called an installation; (确定）? station: in an installation, by using the indexing or moving device the work is changed itsposition relatively to the cutting tool. all the tasks done for the work

4、 in one machining position in an installation is termed as the station; (确定）? step： in one station if the surface cut, cutting tool, velocity, and feed remain unchanged, these working contents are thought of as the step. (加工表面、刀具、切削速度、进给量任一改变均为另一工步）? pass: when the surface of the work is cut for any

5、 one time ,such task carried out is named as the pass? (刀具在加工表面的每一次切削）? processing system:? a system that contains the work to be machined, fixture that holds the work in theproper position, cutting tool that machines the work directly, and machine tool that gives the power and provide the movements

6、 to accomplish the processing. in recent years the gauging and measuring is added to the system.relationship between the batch and the pattern of productionn = qn (1%)n-program of production, q-annual turnout of the product n-number of the components a year,n =na-share rate,bf-annualworking days,-wa

7、sterate, fa- number of days for inventory,-number of components in a lota program of productionin a period of planning, the turnout of product and schedule to be fulfilled is called program. (计划期的产量加进度 =生产纲领）the turnout in one year planning is named the annualprogram .b batch of productionat a time,

8、 the number of identical products to be put into production or to be produced is termed as batch of production.1x, y, and z精品 料推荐(一次投入生产的同一产品的数量=生产批量）process planning for machining operations:stipulated document for technological process (机械加工工艺规程：以工艺文件形式规定的机械加工工艺过程 )patterns of the process planning

9、 for machininggenerally speaking, the process planning for machining appears in the form of sheet or card with the same basic content in three patterns:pattern a: sheet of process procedures(工艺过程卡 ), a very simple and concise document, usually for single/small batch productionpattern b: sheet of pro

10、cess operation (机械加工工艺卡 ), often for batch productionpattern c: sheet of process sequence ( 机械加工工序卡 ), with detailed and complete contents, frequently for massive productionsection 2 location and datum of the work in machininginstallation and clamping(装夹） : concerning about the ways in which the wor

11、k is installed and clamped in the fixture or on the machine tool, including two aspects, locating( 定位 ) andclamping( 夹紧 ).locating: the procedure during which the work gains its proper position in the fixtureor onthe machine tool.clamping: when the workpiece has gained its correct position in the fi

12、xture, it will be subject tothe external forces while being machined. so, to hold or keep the workpiece in the correct position is definitely required, which is called clamping.six-point locating principles：a cuboid is in cartesian coordinate with six degrees of freedom the six degrees of freedom ar

13、e three linear movements along the three coordinate axes,respectively, and three rotations around these coordinate axes x,y,and zin theory, the locating point is the geometric point; in reality, it is something different with its three dimensions. the following are commonly used in workshops.button

14、locator(支撑钉 );plug(档销 ); supporting plate（支撑板） ; pin/pin locator （长销）button; cut pin/rhombus pin（削边销 /菱形销） ; mandrel（心轴） ; v block （形块）short v block （短形块） ; positioning sleeve（定位套） ; fixed/floating conic pin （固定 /浮动锥销） ; center(顶尖（固定 /浮动） )complete positioning :locating with constraint for all six d

15、egrees of freedom.incomplete positioning : locating with constraint for less than six degrees of freedom.under/over-positioning : the number of constraints of degree of freedom is less than that required. under-positioning ought to be avoided and,over-positioning: the same degree of freedom is const

16、rained by two or even more constraining points, such situation is called over positioning, which will be allowedoccasionally.datum( 基准 ) is the point, line or surface based on which the geometric relation-ships among geometric elements of the object to be worked at are determined. the concept is so

17、important that is may be used for any aspect of production, from design, through manufacturing including sequences of operation, to the gauging and assemblytechnological/process datumssequential datum: on the sequential drawing ,datum that is used in this sequence to determine the size, form, and po

18、sition of the work after being machined is named sequential datum. the three aspects are supposed to be taken into consideration: the priority of sequential datum is2精品 料推荐paid to the design datum, that is use the design datum as sequential datum, the selected datum is favorable for the location and

19、 the gauging of the work, and if the above requirements are hardly met, the datum used to guarantee the technical conditions.datum may be classified into two categories,design datum and technological datum, according to their functions .i design datum: in design of components, the origin from which

20、,according to the assembly relationship of the component and the relative relationship of the structural elements of the component itself, the dimensioning is done. these original positions are called design datums .( 设计图纸上零件标注的起始位置 )ii technological datum: datum used in the process operations is te

21、rmed technological datum, which can be even classified as:locating datum: datum used for the workpiece to gain its proper position in machining, it directly influences the effectiveness of machining. locating datum covers rough datum and finishing datum.a) rough datum /finishing datum : un-machined

22、locating datum, in other word, any locating datum used in the first sequence of operation in the manufacturing process planning is the rough datum; finishing datum: machined locating datum.b) additional/auxiliary datum: the specially designed datum in the workpiece because of the requirement of the

23、mechanical process operations.gauging datum: during and after machining, datum used for measuring and checking theform, position, and error of size , of the workpiece.assembling datum: in assembling datum adopted to determine the relative positions of the work or the component in the product.section

24、 3 design of theroutes of machining processes （工艺路线的制定）consideration must be taken with thelocating datum of the workpiece(定位基准） , the process methods（加工方法）, the order of the processes（加工顺序）, heat treatment（热处理）, testing （检验）， and the related operations（其他工序） .a selection of locating datums(定位基准的选择

25、)b selection of economic accuracy and process methods of machining（机加的经济精度与方法）c machining routes for the typical surfaces（典型表面的加工路线 外圆、孔和平面）d order of sequences（工序顺序安排）selecting rules of rough machining datum:iguarantee the proper relative positions .iiguarantee reasonable allocation of the allowanc

26、e for the surface being machined .iii facilitate the locating and clamping of the workpiece. for this reason, the selected surfaces as the datums must be to some extent smooth, enough-sized, flasher-free , without other defects such as reservoir and riser or the like.iv the rough locating datum used

27、 only for one time (without repetition)selecting rules of finishing machining datum:ioverlapping principle( 基准重合） -datum used as the same as design datumii unifying principle （基准统一） -use the same datum as early and as frequently as possible iii inter-reference principle （互为基准） -especially used for t

28、he high accuracy of relative positions of the surfacesiv self-reference principle （自为基准 )- for sequence of small roughness, small and even allowancev clamping-facilitating/convenient principle （便于装夹） -for proper and secure (reliable)3精品 料推荐locating, simple structure of the clamping device with easy

29、operation economic accuracy in machining ( 加工精度 )under the common machining conditions , that is , with facilities and tooling in standard quality, the operators with typical skills, and in rated time ,the machining is done with the relevant accuracy and roughness imparted to the component. such acc

30、uracy and roughness is called the economic accuracy in machiningorder of sequences（工序 序安排）a datum first then others; b flat first then others, generally; c the main surfaces first; d rough machining first, followed by finishing machiningcentralized, decentralizes sequences and the machining stages i

31、 rough machiningii semi-finishing machining iii finishing machiningiv precision, ultra-precision ,and smooth machiningsection 4 determination of machining allowance, dimensions between sequences, and tolerancemachining allowance : the difference between the size of the blank and that of the componen

32、t design on drawingthe total allowance is equal to the sum of material thickness to be removed for every step in the process operation.sequential allowance : the thickness of metal removal of the cut layer in every sequence the relationship between the total allowance and sequential allowance will b

33、e expressed interms ofnzo=z1+z2+ +zn=i=1 zichapter two design principles of machine tool jigs andfixturessection 1 introduction to the machine tool jigs and fixturesfunction, constituents, and classification （ 具的功用， 成和分 ）function: the machine tool jig or fixtureis a device used in machine toolby whi

34、ch theworkpiece obtains and keeps the proper position relative to the machine tool before and during the workpiece being machined.constituents of the fixture : six elements or units of a jig or fixturei locating elements: for locating the work, such as button locator, base (body), and rhombus. ii to

35、ol guide: for guiding the tool or adjusting relative position of the tool to the fixture, such as ,tool setting block.iii clamping device: for holding the work firmly,such as the bolt, screw, and the heel.iv connecting elements: for determining the position of the fixture on the machine tool and con

36、necting the fixture with the machine tool ,such as the locating key, and the base.v body: for connecting all the elements and devices as a whole, and through the body the fixture being fixed to the machine tool, such as the base.vi additions: for other purposes ,like indexing, safeguarding, error-av

37、oiding and the like, such asthe stop pin.classification of the fixture:accordingto the range of usage, fixtures can generally be classified into six categories :all-purpose, special, all-purpose adjustable and group, composite, transferring fixtures.in accordance with the machine tool on which the f

38、ixture is utilized, fixtures can also be classified into lathe, milling machine, drill, borer, grinder, automatic machine tool, and nc4精品 料推荐machine tool, fixtures.based on the power which drives the clamping devices to hold the work firmly in place, fixtures can even be classified into manual, pneu

39、monic, hydraulic, electric-magnetic , and vacuum, fixturessection 2 workpiece-location in the fixture* the analysis and calculation of locating errorcommonly used methods of locating and the locating elements（the surfaces of the workpiece) a locating by flat/plane/surface（平面定位）fixed/adjustable/self-

40、adapted/auxiliary support(固定 /可调 /自位 /辅助支承 )section 3 workpiece-clamping in the fixturerequirements of the clamping forcesdetermination of the clamping forcescommonly used clamping mechanismsrequirements of the clamping forcesisustain, during the whole period of clamping, the proper position of the

41、workpiece when it locatesii be reliable and proper. the clamping mechanisms are, usually, supposed to have the function of self-locking, guaranteeing the clamping device being free from relief and vibration. onthe other hand, preventing ought to promise from being unwanted deformation and the damage

42、 of the surfaces.iii it is taken for grant that the clamping device is convenient, not energy-consuming, and safe, to operate.ivbe consistent ,for the complexity and level of automation of the clamping device, with thebatch production and the pattern of productionadirectionthe following rules should

43、 be ensured:favorable for the workpiece locatingparallel to the direction of the most rigid of the workpreferable to parallel to the direction of the cutting forces, or the gravity of the work to reducethe clamping forceb exerting pointunder the given force, to select the point at which the clamping

44、 force actuates and the number of the exerting pointsi the exerting point coincides with the supports of the fixture or is on the supporting area backed by the supports.ii the exerting point ought to be so set that the touched area has great rigidity of the work, in order to reduce the deformation o

45、f the work possible to occur.iii it is preferable to exert the clamping force at the as near place of the being cut surface as possible to eliminate the turn-over moment by the cutting forces.c magnitude of the clamping forcessection 4 types of machine tool mixturesdrill jigs; borer jigs; milling ma

46、chine fixtures; lathe fixtures; group fixtures; composite fixtures;transferring fixtureschapter three mechanical process accuracy1 concept of the machining accuracy and the influencing factors2 geometric accuracy influencing the machining accuracy5精品 料推荐3 deformation of the processing system from ex

47、ternal forces4 deformation of the processing system caused by heat5 statistics and analysis, and ways of guaranteeing and enhancing the machining accuracysection 1 brief introduction to machining accuracythe qualityof a component by machining contains two-fold,one is mechanical processaccuracy ,and

48、another is the integrity of machined surfaces .here we discuss the first aspect of the quality of the component .mechanical process accurac y is the degree of the real geometry (including the size, form, and relative position between surfaces ) of a workpiece imparted by machining that approaches th

49、e perfect geometry.influencing factors of machining accuracy1) installation of the workpiece(工件的装夹 ) installing error of the workpiece （工件装夹误差）2) adjustment of the processing system（机床、刀具和夹具的调整） geometric error of the processing system（工艺系统几何误差）3) machining operation （加工过程） dynamic error(动误差 )sensib

50、le direction of the error: on the workpiece the initial errors vary both in magnitude and in direction, when the direction of initial error is parallel to that of the sequential size, such error has the greatest influence on the machining accuracy. so we call this directionsensible direction of the

51、error.section 2 the influence of geometric accuracy of the processing system on the machining accuracya error of principle in machining( 加工原理误差 )b error of adjustment(调整误差 )c error of machine tools(机床误差 )guiding error of the guide-way,for a linear guide-way, the guiding accuracy includeslinearity on

52、 the horizontal plane, y, linearity on the vertical plane, z, parallelism between the two guide-ways ( warp，扭曲 ), and the parallelism between the guide-way and the axis of the spindlerotating error of the spindlenotion ：rotating accuracy of the spindle is one of the main aspects of accuracy. rotatin

53、g accuracy of the spindle influences mainly the accuracy of geometric form, position, and roughness, of the machined surfaces because of its function of installing and clamping the work or tool, and providing the primary power and machining movement.rotating error of the spindle is the real floatati

54、on/drift of the rotating axis from the perfect rotating axis of the spindle, including radial-round flounce, facial-round flounce, and inclined-angular swing.and transmitting error of the transmission linkaged error of the fixture in its own production and wear（夹具制造误差与磨损）e error of the tool in its o

55、wn production and wear（刀具制造误差与磨损）section 3 deformation of the processing system from external forcesbasic concept: in machining, any element or all the elements of the processing system may be subjected to cutting force, clamping force, and weight, leading to deform, and further cause machining erro

56、rsthe ability to resist the deformation is often expressed in terms of rigidity k ( 刚度 ) of the6精品 料推荐system，which means the ratio of the normal component of the cutting force to the displacement of the work in the direction of the normal component of the cutting force section 4 deformation of the processing system caused by heata) notion of the deformation from heat, and the heat