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Flatness and Level
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Flatness and Level

Flatness and Level ApplicationFlatness and Level

Measuring Flatness and Level


Both the same thing? Not quite! With the T430 you can measure both simultaneously. You can also measure the flatness and level of separated objects. Two of more separated tables for example.

Definition of Perpendicularity

The tolerance zone is defined by two parallel planes above and below the best fit plane through the measured data. The tolerance planes are separated by the tolerance t. As with the line above, if we have measured 20 points. The best fit plane is the plane where the sum of the errors (hills and valleys) is a minimum.
Don’t forget: The flatness of a plane makes no comment about how level (wrt gravity) a plane is.




The Tolerance Zone is here, like flatness, defined by two parallel planes above and below the data. The difference here is that the planes must be orthogonal (at right angles) to gravity. In plain English: These measured points are described as level or “in water” when they lie within a given tolerance (t) to a supposed waterline drawn through the average height of the points.

Software Screen

We must first distinguish between flatness and level. 

In mathematics, the flatness of a surface is the degree to which it approximates a mathematical plane. We call this plane level if it is on average orthogonal (at right angles) to gravity. (Sometimes called “in water”). So we only talk about something being level if it is also very flat. 

To measure flatness we require a reference plane. To measure level we require a reference to gravity. Typically we measure a matrix of points or angles and interpolate between these discrete measurements.


Spezification and mechanical Adaption

In engineering applications we measure and sometimes correct the flatness of machine components. In flatness and straightness measurements the mechanical adaptation has a dramatic effect on what we measure. It is important to consider the flatness specification in detail in order to choose an appropriate method.

A flatness can state that all points on the surface shall lie between two parallel planes separated by "X" distance, where "X" is the flatness tolerance. It can specify a tolerable wave over a specific area. Alternatively it can specify the variance of the deviation for a best fit plane. Often the specification will define explicitly or inexplicitly how the measurement must be performed.