: The tolerance class for shape and position (straightness, flatness, and parallelism). Typical Applications
If you are a design engineer, using this standard correctly will save your workshop hours of confusion.
The keyword is a specific shorthand found on engineering drawings. Let us break it down: en iso 13920-bf
The measurement method must be appropriate for the precision required. For Class B tolerances, reliable squares, calipers, and straightedges are generally adequate. In contrast, Class A tolerances often necessitate more expensive instruments like laser measurement systems or coordinate measuring machines (CMMs). Testing methods are defined in the standard, including:
While Class B is versatile, it is not always the right choice. : The tolerance class for shape and position
The actual permissible deviation (in millimeters or degrees) depends on the of the part. For example, a 1,000 mm beam in Class B will have a specific allowed variation, whereas a 10,000 mm beam will have a larger allowable margin. Type of Measurement Class for "BF" Key Focus Areas Linear Dimensions B (Medium) Length, width, and height of parts. Angular Dimensions B (Medium) Deviations in angles and slopes. Shape & Position F (Medium) Straightness, flatness, and parallelism . Testing and Verification
To truly understand "EN ISO 13920-BF," you must know the numbers. Below are the key tolerance ranges for (Medium). Let us break it down: The measurement method
If that same beam has a flatness requirement: