【正文】
ues of dimensioning and some monly used structures so that the dimensions will not only meet the design requirements but also other requirements to facilitate machining, measurement and inspection. 使所標注的尺寸既能滿足設(shè)計要求 ,又符合生產(chǎn)實際 , 便于加工、測量和檢驗。 Design datum This class includes datum planes or datum lines used to locate a given part inside other parts. 設(shè)計基準 是用于確定零件 在部件中工作位置的基準面或線。Dimensioning 零件圖的尺寸標注 Datum features 尺寸基準的選擇 Direct specifications of important dimensions 重要的尺寸直接注出 Avoiding close dimension chains 避免出現(xiàn)封閉的尺寸鏈 Producing dimensions in accordance with machining sequence 標注尺寸應(yīng)符合加工順序 Only one link allowed between machined and nonmachined surfaces 同一個方向只能有一個非加工面與加工面聯(lián)系 Exercises 練習(xí)題 請點擊相應(yīng)標題顯示其內(nèi)容 請點擊鼠標左鍵顯示后面內(nèi)容 Datum features 尺寸基準的選擇 When selecting a datum, one must consider the part position, function, assembling, position setting and measurement. Therefore, datum features should be determined according to the design’s requirements, machining conditions, and measurements. 在選擇尺寸基準時 , 必須考慮零件在機器或部件中位置 、 作用 、 零件之間的 裝配關(guān)系以及零件在加工過程中的定位和測量等要求。因此 , 基準應(yīng)根據(jù)設(shè)計要求 、 加工情況和測量方法確定。 Process datum This class includes datum plane or datum line used to machin