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Geometric tolerances indicate the maximum allowable variations in the geometry defined by a drawing. progeCAD draws geometric tolerances using a feature control frame, which is a rectangle divided into compartments.
Each feature control frame consists of at least two compartments. The first compartment contains a geometric tolerance symbol that indicates the geometric characteristic to which the tolerance is applied, such as location, orientation, or form. For example, a form tolerance may indicate the flatness or roundness of a surface. The geometric tolerance symbols and their characteristics are shown in the following table.
Symbol | Characteristic | Type |
---|---|---|
| Position | Location |
| Concentricity or coaxiality | Location |
| Symmetry | Location |
| Parallelism | Orientation |
| Perpendicularity | Orientation |
| Angularity | Orientation |
| Cylindricity | Form |
| Flatness | Form |
| Circularity or roundness | Form |
| Straightness | Form |
| Profile of a surface | Profile |
| Profile of a line | Profile |
| Circular runout | Runout |
| Total runout | Runout |
The second compartment contains the tolerance value. When appropriate, the tolerance value is preceded by a diameter symbol and followed by a material condition symbol. The material conditions apply to features that can vary in size. The material condition symbols and their meanings are shown in the following table.
Symbol | Definition |
---|---|
| At maximum material condition (MMC), a feature contains the maximum amount of material stated in the limits. |
| At least material condition (LMC), a feature contains the minimum amount of material stated in the limits. |
| Regardless of feature size (RFS) indicates that the feature can be any size within the stated limits. |
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