【正文】 s fit properly. 它讓機械工程師的能力放大甚至最小的組件來確定如果組裝組件配合得當。 Designers have even more freedom with the advent of 3D parts and manipulate them in endless variations to achieve the desired results. 設計師有更多自由隨著3 d部分和操縱他們無窮無盡的變化來獲得期望的結果。 In addition to the design’s geometric and dimensional featuresother information such as a list of
materialsspecification and manufacturing instructionsis stored in the CAD database. Using such
information ,the designer can then analyze the economics of alternative designs. 除了設計的幾何和空間特性,其他信息(如材料的清單,規(guī)范,和生產(chǎn)指令)存儲在CAD數(shù)據(jù)庫。 Computeraided manufacturing(CAM) involves the uses of puters and puter technology to assist
in all the phases of manufacturing a productincluding process and production planningmachining
schedulingmanagement and quality control. Computeraided design and puteraided
manufacturing are often bined into CAD/CAM systems. 計算機輔助制造(CAM)涉及計算機和計算機技術的使用,協(xié)助生產(chǎn)一個產(chǎn)品的所有階段,包括
過程和生產(chǎn)計劃、加工、調度、管理和質量控制。 This bination allow the transfer of information from the design stage into the stage of of planning for
the manufacture of a productwithout the need to reenter the data on part geometry manually. 這種組合允許轉讓信息從設計階段的階段,規(guī)劃產(chǎn)品的生產(chǎn),而不需要手動重新輸入數(shù)據(jù)部
分幾何。然后進一步處理,通過凸輪,到所需的數(shù)據(jù)和指令操作和控制生產(chǎn)
機械、設備來源,自動化測試和檢驗產(chǎn)品質量。 The instructions programsare puter generatedand they can be modified by the programmer to
optimize the tool path . 計算機生成的指令(程序),他們可以由程序員修改優(yōu)化刀具軌跡。工具路
徑隨時可以修改,以適應其他部分形狀加工。(b)設計的工具和夾具
和EDM electodes。(d)工藝規(guī)
劃和調度。 The emergence of CAD/CAM has had a major impact on manufacturingby standardizing product
development and by reducing design efforttryoutand prototype workit has made possible significantly
reduced costs and improved productivity. CAD / CAM的出現(xiàn)已經(jīng)對生產(chǎn)產(chǎn)生重大影響,通過標準化產(chǎn)品開發(fā)和減少設計工作,調試,和
原型工作。 The twoengine Boeing 777 passenger airplanefor example, was designed pleted by puter
paperless design . The plane is constructed directly from the CAD/CAM software developedan
enhanced CATIA systemand no prototypes or mockups were built such as were required for previous
models. 雙引擎的波音777客機,例如,設計完成的計算機(無紙化設計)。50課 Today, puter numerical control machine tools are widely used in manufacturing enterprises.
Computer numerical control is the automated control of machine tools by a puter and puter
program. 今天,計算機數(shù)控機床廣泛應用于制造企業(yè)。 The CNC machines still perform essentially the same functions as manually operated machine toolsbut
movements of the machine tool are controlled electronically rather than by hand. CNC machine tools can
produce the same parts over and over again with very little variation. They can run day and nightweek
after weekwithout getting tired. These are obvious advantages over manually operated machine tools
which need a great deal of human interaction in order to do anything. 數(shù)控機器仍執(zhí)行相同的函數(shù)作為手動機床,但機床控制電子的運動,而不是用手。他們可以日夜不停地運轉,一周又一周,沒有累了。 A CNC machine tool differs from a manually operated machine tool only in respect to the specialized
ponents that make up the CNC system. The CNC system can be further divided into three
subsystemscontroldriveand feedback. All of these subsystems must work together to form a plete
CNC system. 數(shù)控機床不同于一個手動機床只有在尊重專業(yè)的組件構成的數(shù)控系統(tǒng)。所有這些子系統(tǒng)必須共同努力,形成一個完整的數(shù)控系
統(tǒng)?？刂葡到y(tǒng) The centerpiece of the CNC system is the control. Technically the control is called the machine control
unitMCUbut the most mon names used in recent years are controllercontrol unitor just plain
control. This is the puter that stores and reads the program and tells the other ponents what to
do. 數(shù)控系統(tǒng)控制的核心。這是計算機存儲和讀取程序,告訴其他組件該做什么。驅動系統(tǒng)。第一個組件的典型的驅動系統(tǒng)是一
種高精度絲杠稱為滾珠絲桿()。首先,
不能實現(xiàn)高精度定位如果表是免費的移動略當它應該是固定的。爬上切割通常是最可取的方法在數(shù)控加工機器。電動機的轉動將滾珠螺桿直接導致加工表。 The simplest type of electric motor used in CNC positioning systems is the stepper motorsometimes
called a stepping motor. A stepper motors rotates a fixed number of degrees when it receives an
electrical pulse and then stops until another pulse is received. The stepping characteristic makes stepper
motors easy to control. 最簡單的類型的電動機用于數(shù)控定位系統(tǒng)是步進電機(有時稱為步進電機)。步進特性使步進電機容易
控制。伺服電機運行在一個光滑、連續(xù)的活動,如
離散運動的步進電機。需要專
門的硬件控制和反饋系統(tǒng)控制和驅動這些汽車。 3. Feedback System 3。 The control can pare the desired condition to the actual condition and make corrections. The most obvious information to be fed back to the control on a CNC machine 控制可以比較所需的條件的實際條件和改正。其他信息也可以反饋,不是直接關系到運動控制,如電動機的溫
度和負載spindlethis信息保護機器免受損壞。All the control knows is that it delivered the instructions.
Openloop control is not used for critical systemsbut it is a good choice for inexpensive motion control
systems in which accuracy and reliability are not critical. 主要有兩種類型的控制系統(tǒng):開環(huán)和閉環(huán)。例
如,在一個開環(huán)系統(tǒng),控制可以給指令將電動機10革命。開環(huán)控制不用于關鍵系統(tǒng),但這是一個不
錯的選擇廉價的運動控制系統(tǒng)的精度和可靠性并不是最關鍵的。當然,位置和速度反饋是最重要的一個精
確的數(shù)控系統(tǒng)