Krzysztof Stępień

DEFINING THE CRITERIA TO SELECT THE WAVELET TYPE FOR THE ASSESSMENT OF SURFACE QUALITY

The paper deals with one of the most important problems in the wavelet analysis – the methodology for mother wavelet selection. In this study, the surface texture of machine parts was assessed applying a wavelet transform. The calculations involved in roughness profile evaluation were based on three selection criteria: an autocorrelation test, a cross-correlation function and an entropy-based test. All the calculations and diagrams were produced using the Wavelet toolbox of the MATLAB package.

Testing the Accuracy of Surface Roughness Measurements Carried out with a Portable Profilometer

Surface roughness is a factor that has a vital influence on overall quality of machine parts. This is the reason why proper measurements of surface roughness are a matter of great importance in modern manufacturing technology. Nowadays portable profilometers are common instruments to be used under industrial conditions. Measurements with such instruments can be affected by numerous factors, for example environmental changes, human errors of an operator, etc. This paper discusses problem of an evaluation of measurement accuracy of portable profilometers. It also describes the evaluation procedure and presents results experimental tests.

Problems of Mathematical Modelling of Rotary Elements

Rotary elements constitute a large and significant group of machine parts. Such parts are used in various branches of industry, for example in bearing, automotive, paper, shipping or power industry. Most of rotary machine parts are cylindrical ones but sometimes other types of elements are used, as spheres, cones or barrel-shaped and saddle-shaped elements. Measurements of form deviations of such elements require performing a number of mathematical operations on measurement data, including calculation of reference features. The basis for such operations is to apply an appropriate mathematical model of the surface. Scientific literature and standards refer mainly to measurements of form errors of cylindrical shapes. Apart from the cylindrical surfaces, this paper discusses also the problem of mathematical modelling of cones, spheres and barrel-shaped elements.

Assessment of an Influence of Real Values of V-Block Method Parameters on the Method Accuracy of V-Block Waviness Measurement of Rotary Machine Parts

The article deals with an application of the V-block method to waviness measurements of rotary mechanical parts. The most popular methods used to measure waviness profile are radial ones. These methods are characterized by a high measurement accuracy and they are usually used to measure waviness profile of small parts under laboratory conditions. Furthermore radial waviness measurements are time-consuming due to centering of measured object on measuring table. Since, large size cylinders are used in many branches of industry, it is necessary to develop another method that allows to determine waviness deviations under industrial conditions. For this purpose the V-block method can be applied. This article presents a design and a principle of operation of a measuring device based on the V-block method. The device was used in the experimental part of the research work to measure waviness profiles. Paper describes also the procedure of identification of real values of V-block method parameters (angles α and β) used in measuring device. For the nominal and real values of angles α and β an experimental V-block method accuracy was calculated. The research result presented in this article indicate that the identification of real values of V-block method parameters increases the method accuracy.