What type of geometric tolerances control attributes like flatness and straightness?

Form tolerances are specifically designed to control the shape or geometry of a part, addressing attributes like flatness and straightness. When a drawing specifies a flatness tolerance, it establishes limits to ensure that a surface does not deviate from being perfectly flat. Similarly, straightness tolerances ensure that a line or edge does not curve or deviate from a straight path. These tolerances are crucial in welding and manufacturing processes where the accuracy of the shape affects assembly, function, and overall quality of the final product.

Location tolerances typically deal with the position of features relative to each other, orientation tolerances control the angle of features in relation to a reference, and profile tolerances define a shape’s contour but do not specifically address flatness or straightness in the same direct way form tolerances do. Thus, form tolerances are the appropriate choice for regulating such attributes.