Pavol Hreha

Potential use of vibration for metrology and detection of surface topography created by abrasive waterjet

This paper deals with an experiment with the material of AISI 309 with thickness of 15 mm, to carry out the research into material vibration phenomena as the tool of the online controlling of surface texture created by abrasive waterjet. Vibrations of the material were collected by accelerometers of PCB IMI 607 A11. The generated topography on material was measured with optical profilometer MicroProf FRT and the data were confronted with the resultant vibration parameters. A new parameter VRa [g] is proposed to detect the surface texture by vibration. New equations for detecting the surface quality were derived.

Rationalization of manufacturing of plastic injection moulds by abrasive waterjet

The article deals with a proposal and a theoretical solution for the rationalization of manufacturing of parts of plastic injection moulds by abrasive waterjet cutting. On the basis of experimental tests and by the application of advanced abrasive waterjet technology to the process of manufacturing of plastic injection moulds, it has been found that there is a possibility of considerable time saving, i.e. a marked shortage in time period from product ordering to dispatching. In such a way it is possible to increase the competitiveness of a company and to ensure its stable position on the market even in the time of global crisis.

INFLUENCE OF FOCUSING TUBE WEAR ON VIBRATIONS AND SURFACE ROUGHNESS

Original scientific article The paper deals with the study of the focusing tube wear influence on surface quality and vibrations produced by abrasive waterjet by means of experiments design. The experiments deal with evaluation of the influence of focusing tube wear on surface quality and parameters of vibration generated by abrasive waterjet cutting. The main task of the first experiment was to study the significance of four selected factors of independent variables (focusing tube wear, traverse rate, abrasive mass flow rate and pressure) by full factorial analysis at two levels. The aim of the second experiment was to study the influence of focusing tube wear on the vibration parameters. It has been observed that focusing tube wear has a significant negative influence on surface quality and parameters of vibration.