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英语翻译
2.Either a shaft-based system or a hole-based system may be used .For any given basic size ,a range of tolerances and deviations may be specified with respect to the line of zero deviations ,called the zero line .The tolerance is a function of he basic size and an is designated by a number symbol ,called the grade―thus the tolerance grade .The position of the tolerance with respect to the zero line also a function of the basic size--is indicated by a letter symbol (or two letters ) ,a capital letter for holes and a lowercase letters for shafts .The specification forget a hole and shaft having a basic size of 45 mm might be 45 H8/g7 .
3.CAD system can created and displayed graphic information on a cathode-ray tube (CRT ),and it allows the designer to produce finished engineering drawings from single pensile sketches or from models and modify these drawings on the screen if they do not seem functional .From three-drawing ,orthographic views ,the designer can transform drawings into athree-dimensional views .This enable a designer to redesign a part on the screen ,project how the part will operate in use ,and make successive design changes in a matter of minutes .
2.Either a shaft-based system or a hole-based system may be used .For any given basic size ,a range of tolerances and deviations may be specified with respect to the line of zero deviations ,called the zero line .The tolerance is a function of he basic size and an is designated by a number symbol ,called the grade―thus the tolerance grade .The position of the tolerance with respect to the zero line also a function of the basic size--is indicated by a letter symbol (or two letters ) ,a capital letter for holes and a lowercase letters for shafts .The specification forget a hole and shaft having a basic size of 45 mm might be 45 H8/g7 .
3.CAD system can created and displayed graphic information on a cathode-ray tube (CRT ),and it allows the designer to produce finished engineering drawings from single pensile sketches or from models and modify these drawings on the screen if they do not seem functional .From three-drawing ,orthographic views ,the designer can transform drawings into athree-dimensional views .This enable a designer to redesign a part on the screen ,project how the part will operate in use ,and make successive design changes in a matter of minutes .
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