1、制造技術基礎復習基本概念、基本原理英語表達參考Review the Basic Concepts and Principles of Fundamentals of Manufacturing Technology in EnglishCHAPTER ONE DESIGN FOR MECHANICAL PROCESS PLANNINGSection 1 Basic concepts Production procedure of mechanical products Process procedure of machiningElements of Process procedure of

2、machining 1 sequence 工序；2 installation 安裝；3 station 工位；4 step工步； 5 pass走刀 Sequence: process procedure that consists of several sequences during which workers operate on the works continuously in the same place;(操作者、加工地、工作對象人為劃分，相對可變) Installation: in a sequence if the work is required to put into po

3、sition and clamp several times,the part of sequence done in one positioning and clamping is called an installation;(確定） Station: In an installation, by using the indexing or moving device the work is changed its position relatively to the cutting tool. All the tasks done for the work in one machinin

4、g position in an installation is termed as the station;(確定） 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、進給量任一改變均為另一工步） Pass: When the surface of the work is cut for any one time ,such task

5、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 the proper position, cutting tool that machines the work directly, and machine tool that gives the power and provide the movements to accomplish the proc

6、essing. In recent years the gauging and measuring is added to the system.Relationship between the batch and the pattern of productionN-program of production, Q-annual turnout of the productn-number of the components a year, -share rate, -waste rate, F -annual working days, A- number of days for inve

7、ntory, -number of components in a lotA Program of production In a period of planning, the turnout of product and schedule to be fulfilled is called program. (計劃期的產量加進度=生產綱領）The turnout in one year planning is named the annual program .B Batch of production At a time, the number of identical products

8、 to be put into production or to be produced is termed as batch of production.(一次投入生產的同一產品的數(shù)量=生產批量）Process planning for machining operations :stipulated document for technological process (機械加工工藝規(guī)程：以工藝文件形式規(guī)定的機械加工工藝過程)Patterns of the process planning for machining Generally speaking, the process plan

9、ning for machining appears in the form of sheet or card with the same basic content in three patterns:Pattern A: sheet of process procedures(工藝過程卡), a very simple and concise document, usually for single/small batch productionPattern B: sheet of process operation (機械加工工藝卡), often for batch productio

10、nPattern C: sheet of process sequence (機械加工工序卡), with detailed and complete contents, frequently for massive productionSection 2 Location and Datum of the work in machiningInstallation and clamping(裝夾）: concerning about the ways in which the work is installed and clamped in the fixture or on the mac

11、hine tool, including two aspects, locating(定位) and clamping(夾緊).Locating: the procedure during which the work gains its proper position in the fixture or on the machine tool.Clamping: when the workpiece has gained its correct position in the fixture, it will be subject to the external forces while b

12、eing 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 are three linear movements along the three coordinate axe

13、s, respectively, and three rotations around these coordinate axes In 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 locator(支撐釘);Plug(檔銷); Supporting plate（支撐板）; Pin/pin locator （

14、長銷）Button; Cut pin/rhombus pin（削邊銷/菱形銷）; Mandrel（心軸）; V block（形塊）Short V block （短形塊）; Positioning sleeve（定位套）; Fixed/floating conic pin（固定/浮動錐銷）; Center(頂尖（固定/浮動）)Complete positioning :locating with constraint for all six degrees of freedom.Incomplete positioning: locating with constraint for less t

15、han 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 constrained by two or even more constraining points, such situation is called over p

16、ositioning, which will be allowed occasionally.Datum(基準) 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 important that is may be used for any aspect of production, from design, through

17、 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 position of the work after being machined is named Sequential datum. The three asp

18、ects are supposed to be taken into consideration: the priority of sequential datum is paid to the design datum, that is use the design datum as sequential datum, the selected datum is favorable for the location and the gauging of the work, and if the above requirements are hardly met, the datum used

19、 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 ,according to the assembly relationship of the component and the relative relationship

20、 of the structural elements of the component itself, the dimensioning is done. These original positions are called design datums .(設計圖紙上零件標注的起始位置)II technological datum: datum used in the process operations is termed technological datum, which can be even classified as:Locating datum: datum used for

21、 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 locating datum, in other word, any locating datum used in the first sequence of operatio

22、n 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 mechanical process operations.Gauging datum: during and after machining, datum used for

23、measuring and checking the form, 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 3 Design of the routes of machining processes（工藝路線的制定）Consideration must be taken with

24、 the locating datum of the workpiece(定位基準）, the process methods（加工方法）, the order of the processes（加工順序）, heat treatment（熱處理）, testing（檢驗）， and the related operations（其他工序）. A selection of locating datums(定位基準的選擇)B selection of economic accuracy and process methods of machining（機加的經濟精度與方法）C machining

25、 routes for the typical surfaces（典型表面的加工路線外圓、孔和平面）D order of sequences（工序順序安排）Selecting rules of rough machining datum:I guarantee the proper relative positions .II guarantee reasonable allocation of the allowance for the surface being machined .III facilitate the locating and clamping of the workpi

26、ece. 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 only for one time (without repetition)Selecting rules of finishing machining datum:I o

27、verlapping principle(基準重合）-datum used as the same as design datumII unifying principle（基準統(tǒng)一）-use the same datum as early and as frequently as possibleIII inter-reference principle（互為基準）-especially used for the high accuracy of relative positions of the surfacesIV self-reference principle（自為基準)- for

28、sequence of small roughness, small and even allowance V clamping-facilitating/convenient principle（便于裝夾）-for proper and secure (reliable) locating, simple structure of the clamping device with easy operationEconomic accuracy in machining (經濟加工精度)Under the common machining conditions , that is , with

29、 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 accuracy and roughness is called the economic accuracy in machining Order of sequences（工序順序安排）a datum firs

30、t 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 rough machining II semi-finishing machiningIII finishing machining IV precision, ultra-precision ,and

31、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 component design on drawing the total allowance is equal to the sum of material thickness to be removed for eve

32、ry step in the process operation.Sequential allowance: the thickness of metal removal of the cut layer in every sequenceThe relationship between the total allowance and Sequential allowance will be expressed in terms of Zo=Z1+Z2+Zn=CHAPTER TWO DESIGN PRINCIPLES OF MACHINE TOOL JIGS AND FIXTURESSecti

33、on 1 introduction to the machine tool jigs and fixturesFunction, constituents, and classification（夾具的功用，組成和分類）Function: the machine tool jig or fixture is a device used in machine tool by which the workpiece obtains and keeps the proper position relative to the machine tool before and during the wor

34、kpiece 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 tool guide: for guiding the tool or adjusting relative position of the tool to the fixture, such as ,tool settin

35、g 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 connecting the fixture with the machine tool ,such as the locating key, and the base.V body: for connecting all

36、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-avoiding and the like, such as the stop pin.Classification of the fixture:According to the range of usage, fixt

37、ures 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 fixture is utilized, fixtures can also be classified into lathe, milling machine, drill, borer, grinder, au

38、tomatic machine tool, and NC 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, pneumonic, hydraulic, electric-magnetic , and vacuum, fixtures Section 2 Workpiece-location in the fixture * the ana

39、lysis 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-adapted/auxiliary support(固定/可調/自位/輔助支承)Section 3 Workpiece-clamping in the fixtureRequirements of the clampi

40、ng forcesDetermination of the clamping forcesCommonly used clamping mechanismsRequirements of the clamping forcesI sustain, during the whole period of clamping, the proper position of the workpiece when it locates II be reliable and proper. The clamping mechanisms are, usually, supposed to have the

41、function of self-locking, guaranteeing the clamping device being free from relief and vibration. On the other hand, preventing ought to promise from being unwanted deformation and the damage of the surfaces.III It is taken for grant that the clamping device is convenient, not energy-consuming, and s

42、afe, to operate.IV be consistent ,for the complexity and level of automation of the clamping device, with the batch production and the pattern of productionA Direction The following rules should be ensured: favorable for the workpiece locatingParallel to the direction of the most rigid of the workPr

43、eferable to parallel to the direction of the cutting forces, or the gravity of the work to reduce the clamping forceB Exerting pointunder the given force, to select the point at which the clamping force actuates and the number of the exerting pointsI the exerting point coincides with the supports of

44、 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 of the work possible to occur.III It is preferable to exert the clamping force at the as near place of th

45、e 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 machine fixtures; Lathe fixtures; Group fixtures; Composite fixtures;Transferring fixturesCHAPTER THREE ME

46、CHANICAL PROCESS ACCURACY1 Concept of the machining accuracy and the influencing factors2 Geometric accuracy influencing the machining accuracy3 Deformation of the processing system from external forces 4 Deformation of the processing system caused by heat5 Statistics and analysis, and ways of guara

47、nteeing and enhancing the machining accuracySection 1 Brief introduction to Machining AccuracyThe quality of a component by machining contains two-fold, one is Mechanical Process Accuracy ,and another is the Integrity of Machined Surfaces .Here we discuss the first aspect of the quality of the compo

48、nent .Mechanical process accuracy is the degree of the real geometry (including the size, form, and relative position between surfaces) of a workpiece imparted by machining that approaches the perfect geometry. Influencing factors of machining accuracy1) Installation of the workpiece(工件的裝夾)installin

49、g error of the workpiece（工件裝夾誤差）2) Adjustment of the processing system（機床、刀具和夾具的調整）geometric error of the processing system（工藝系統(tǒng)幾何誤差）3) Machining operation （加工過程）dynamic error(動誤差)Sensible direction of the error: on the workpiece the initial errors vary both in magnitude and in direction, when the d

50、irection 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 direction Sensible direction of the error. Section 2 The influence of geometric accuracy of the processing system on the machining accuracyA error of

51、 principle in machining(加工原理誤差)B error of adjustment (調整誤差)C error of machine tools(機床誤差)Guiding error of the guide-way, For a linear guide-way, the guiding accuracy includeslinearity on the horizontal plane, y, linearity on the vertical plane, z, parallelism between the two guide-ways ( warp，扭曲), a

52、nd the parallelism between the guide-way and the axis of the spindle Rotating error of the spindle Notion：rotating accuracy of the spindle is one of the main aspects of accuracy. Rotating accuracy of the spindle influences mainly the accuracy of geometric form, position, and roughness, of the machin

53、ed 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 floatation/drift of the rotating axis from the perfect rotating axis of the spindle, including radial-round flounce, faci

54、al-round flounce, and inclined-angular swing.and transmitting error of the transmission linkageD error of the fixture in its own production and wear（夾具制造誤差與磨損）E error of the tool in its own production and wear（刀具制造誤差與磨損）Section 3 Deformation of the processing system from external forcesBasic concept

55、: 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 errorsThe ability to resist the deformation is often expressed in terms of rigidity k (剛度) of the system，which means

56、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 forceSection 4 Deformation of the processing system caused by heata) Notion of the deformation from heat, and the heat balance and temperature distributionb)

57、 Influence of the deformation of the work from heat on machining accuracyc) Influence of the deformation of the tool from heat on machining accuracyd) Influence of the deformation of the machine tool from heat on machining accuracye) Ways of reducing the influence of the deformation from heat on the

58、 machining accuracyOrigin of the heat:Internal heat source :mainly the cutting force and friction forces with the conductivityExternal heat source: mainly the environmental temperature with circulation, as well as heat-radiating sourcesThe cutting force is the main and important source of heatThe heat balance and the temperatu