This block contains specific information about how a tolerance applies to a feature. The profile of a surface symbol is an inverted semicircle with a horizontal diameter connecting its two ends. This block defines the geometrical tolerance applied to a feature by housing its symbol. Like any other FCFs in GD&T, the profile of a surface FCF can be divided into three distinct blocks. Profile of a Surface Feature Control FrameĪ leader arrow connects the feature control frame (further referred to as FCF) of the profile of a surface tolerance to the part feature. This is done to achieve greater control at critical cross-sections while the profile of a surface maintains a looser overall control over the full surface. In such a case the line profile’s tolerance is tighter than the profile of a surface. There are times when both profile controls may be applied together. While the profile of a line controls a specific cross-section on the part, the profile of a surface controls every cross-section across the entire length of the surface. The profile of a surface tolerance is the 3D equivalent of the line profile tolerance. Profile of a surface vs line profile tolerance By specifying a datum in the profile of a surface’s feature control frame, we can replicate the function of all orientation controls to maintain a surface in a particular position. In order to orient a part feature in GD&T, we need a reference point such as a datum plane, line, or axis. When used with a datum callout, the profile of a surface can replace all the orientation controls. Profile of a surface vs orientation controls These planes can be either flat or cylindrical. These form controls constrain the form of a part by creating a tolerance zone between two parallel surfaces. When used without a datum, the profile of a surface can replace all the form controls. Let’s see a few examples: Profile of a surface vs form controls ![]() Surface Profile Relation to Other GD&T SymbolsĪs mentioned above, the profile of a surface can effectively replace almost all of the GD&T Callouts whether they are curved or flat. The points on the part’s entire surface must lie within the specified tolerance zone for it to be accepted. A smaller tolerance limit gives tighter control but may be difficult to manufacture. Both planes follow the shape of the ideal surface and the distance between them is the tolerance limit for the callout. The surface profile tolerance zone consists of two parallel planes, bilaterally disposed on each side of the ideal curved surface (aka the true profile). The required surface’s specification must also be within the capabilities of the fabrication process to be used. Thus, it is possible to create highly intricate surface profiles as long as they can be created as a CAD model. The profile of a surface generates a virtual surface that acts as the baseline to measure the actual surface. The profile of a surface callout can help us manufacture these parts by controlling the surface profile during manufacturing and measuring results after production. These surfaces need to be manufactured to great detail for functional reasons. Many engineering parts such as turbine blades, car BiWs and airplane wings have highly complex surfaces. Tip: To avoid clutter and improve performance, when using the Quick Measure tool, it’s best to zoom into complicated areas of your drawing.Profile of a surface controls a part’s surface profile in accordance with the CAD model or the drawing. Watch the Quick Measure Command in ActionĬlick the learn tab on the start-up screen to view the new features video for a summary of the new features in AutoCAD 2020, including the new Quick Measure option. The small yellow square in the corner indicates that the lines are at a right angle. The distance between two objects is measured only if the objects are parallel. ![]() When this option is active the command displays dimensions, distances and angles within a 2D drawing dynamically as you move your mouse over and between objects. Measuring distance in your drawing has become much faster with the new Quick Option of the measure geometry command. The New Quick Option Of The Measure Geometry Command In AutoCAD 2020, measuring distances is faster than ever with the new Quick option of the MEASUREGEOM command, which measures 2D drawings simply by hovering your mouse.
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