形位公差符號及含義英文縮寫

Geometric Dimensioning and Tolerancing (GD&T) is a system of symbols and abbreviations used to communicate engineering design specifications. One important aspect of GD&T is the use of symbols to indicate form, orientation, and location tolerances, known as geometric tolerances. One of the key symbols used for geometric tolerances is the position tolerance, which specifies the allowable deviation of a feature from its exact location.

The position tolerance symbol is represented by a circle with an arrow pointing to a point on the feature. The size of the circle indicates the allowable tolerance zone, while the arrow indicates the exact location of the feature. The position tolerance symbol can be modified with additional symbols to indicate specific requirements, such as a datum reference frame or a maximum material condition.

In addition to the position tolerance symbol, there are several other symbols used for geometric tolerances. These include the straightness symbol, which indicates that a feature must be straight within a specified tolerance zone, and the flatness symbol, which indicates that a surface must be flat within a specified tolerance zone. Other symbols include the circularity symbol, which indicates that a feature must be circular within a specified tolerance zone, and the cylindricity symbol, which indicates that a feature must be cylindrical within a specified tolerance zone.

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Each of these symbols is represented by a unique English abbreviation. For example, the position tolerance symbol is represented by 'P,' while the straightness symbol is represented by 'S.' The flatness symbol is represented by 'F,' the circularity symbol is represented by 'C,' and the cylindricity symbol is represented by 'CYL.'

Understanding these symbols and their meanings is crucial for engineers and designers, as they are used to communicate design specifications and ensure that manufactured parts meet the required standards. By using GD&T symbols and abbreviations, engineering drawings can convey complex tolerances and specifications in a clear and concise manner.