The importance of surface waviness; Problems with 3-D measuring and evaluation techniques

The analysis of surface waviness is simultaneous with the measurement of roughness. Today, however, they are rather ignored. Waviness parameters can only sparsely be found in technical practices while waviness and roughness are both relevant characteristics of the surface. It is especially true to process engineering which is optimised to functioning behaviour.
3D surface measuring, which has gained ground in the past decade, also comprises the -D filtering techniques and involves the same problem areas (the separation of roughness/waviness, evaluation length, cut-off), moreover the analysis of microtypographies raises new issues in this field.
In our study we shall discuss the importance of surface waviness and point out what important role 3D measuring and evaluation techniques play in surface microgeometry and microtopography analyses, furthermore those problems are focused on which may cause difficulties in the 3D interpretation and evaluation of waviness, moreover it they may lead to distorted results.
The following conclusions have been drawn regarding the evaluation of waviness during the 2D and 3D analyses of various cut surfaces: the 3D interpretation of waviness is necessary and indespensable for the comprehensive analysis of surface microtopography. However, the reexamination of filtering technique is also needed; it is important to decide in each case what size of surface should be analysed, what cut-off application is the most suitable, and to what extent the sample-taking distance can be extended without losing information. Furthermore, the standardisation of 3D filtering and evaluation technique is also necessary for the sake of comparisons.