Lead characterisation by an objective evaluation method

A new algorithm for characterising macro-lead is introduced. The algorithm is based on a two-dimensional discrete Fourier transformation of the data set measured by a standard roughness system or a form-tester with a surface texture probe. A data pre-processing ensures the elimination of an eventually radial run out of the work piece. The lead parameters which are relevant to leak-tightness are derived from the position of the most significant peak in the frequency domain and a reconstructed deterministic surface.