Árpád Czifra

Sensitivity of Power Spectral Density (PSD) Analysis for Measuring Conditions

Nowadays power spectral density (PSD) analysis is one of the leading characterisation techniques of surface topography. Fractal dimension obtained from PSD plays a significant role in recent friction, adhesion and wear models.

Measurement uncertainty and gauge capability of surface roughness measurements in the automotive industry: a case study

The calculation methods of the capability of measurement processes in the automotive industry differ from each other. There are three main calculation methods: MSA, VDA 5 and the international standard, ISO 22514–7. During this research our aim was to compare the capability calculation methods in a case study. Two types of automotive parts (ten pieces of each) are chosen to examine the behaviour of the manufacturing process and to measure the required characteristics of the measurement process being evaluated. The measurement uncertainty of the measuring process is calculated according to the VDA 5 and ISO 22514–7, and MSA guidelines. In this study the conformance of a measurement process in an automotive manufacturing process is determined, and the similarities and the differences between the methods used are shown.

Tribological Aspects for Reliable Operation of Engineering Surfaces

Reliable operation of machine elements depends on the tribological properties of contacting elements, such as, the quality of the surface. Microgeometrical characterization of engineering surfaces has standard and non-standard methods, but in many cases of worn surfaces the results of these techniques become unusable. After examining worn surfaces—differential of military land vehicle, cylinder liner of engines and ferrodo-steel sliding couple—a new concept of surface characterization was developed: the feature based concept of surface characterization focusing to the properties of microtopography which determine the operation.