Papers by Wojciech Kacalak
The article presents the scientific problems and development trends of abrasive micromachining. T... more The article presents the scientific problems and development trends of abrasive micromachining. The research problems were characterized and the results of the analysis of research directions based on programs of implemented projects in the world's scientific centers were presented. The most important features of the abrasive micromachining were described. The importance of phenomena important in micromachining were emphasized, such as discontinuity of material removal processes, the importance of friction in the treatment zone and topography of the tool. Scientific problems requiring solutions, important for increasing the efficiency of processes micromachining were indicated. New methods of the micro grinding and criteria for modeling and simulation of grinding processes were presented. Proposals for directions for further research and industrial applications of new processes and tools for abrasive micromachining were developed.
Materials
This paper presents the fundamentals of the design and applications of new worm gear drive soluti... more This paper presents the fundamentals of the design and applications of new worm gear drive solutions, which enable the minimisation of backlash and are characterised by higher kinematic accuracy. Different types of worm surfaces are briefly outlined. Technological problems concerning the principles of achieving a high degree of precision in machining are also described. Special attention is paid to the shaping of conical helical surfaces. Increasing the manufacturing precision of drive components allows one to achieve both lower backlash values and lower levels of its dispersion. However, this does not ensure that backlash can be eliminated, with its value being kept low during longer periods of operation. This is important in positioning systems and during recurrent operations. Various design solutions for drives in which it is possible to reduce backlash are presented. Results of experiments of a worm gear drive with a worm axially adaptive only locally, in its central section, ar...
Mechanik
Micro-finishing with abrasive foils is characterized by a single use of the tool, which makes it ... more Micro-finishing with abrasive foils is characterized by a single use of the tool, which makes it necessary to optimally fill the space between the grains of the processing products. Microscopy research with the use of scanning electron microscopy enables a more complete evaluation of the machining process. Based on the structure of micro-chips, the phenomena occurring in the micro-finishing zone with foils with electrocorunded abrasive grains with a nominal size of 15 μm have been described. It has been shown that the analysis of micro-chips, the bottoms of machining marks and the size of micro-chips with segmentation construction allows to estimate the frequency of process discontinuities. Different types of spherical chips, created as a result of very high temperatures, are also presented as a phenomenon unfavorable for the process.
Mechanik, 2015
W artykule przedstawiono badania mikrowiórów tworzonych w procesie mikrowygładzania foliami ścier... more W artykule przedstawiono badania mikrowiórów tworzonych w procesie mikrowygładzania foliami ściernymi. Przeanalizowano cechy geometryczne mikrowiórów i stwierdzono występowanie bardzo długich wiórów w porównaniu do ich szerokości. Zaobserwowano również, występowanie wiórów kulistych, co należy uznać za skutek występowania lokalnie bardzo wysokich temperatur w strefie obróbki. Zaobserwowano istnienie dwóch charakterystycznych struktur wiórów kulistych oraz zbadano ich skład chemiczny. Na podstawie płytkowej budowy wiórów wstęgowych wyznaczono cechy mikronieciągłości w procesie mikroskrawania. SŁOWA KLUCZOWE: mikrowióry, produkty obróbki, folie ścierne, nieciągłość procesu Studied micro-chips created in the process of micro-abrasive films. Analyzed geometrical characteristics of the microchips, are at very long chips compared to their width. It was also observed, the presence of high temperature in the treatment zone, which resulted in the formation of chip like sphere. It has been observed that there are two characteristic structures of spherical chips and examined their chemical composition. On the basis of the strip-like plate construction chip set features micro-discontinuities in the Microcutting.
Materials
The dynamic impact of a water jet with a periodically changing structure can be used in various i... more The dynamic impact of a water jet with a periodically changing structure can be used in various industries. The paper presents a design solution for a self-excited pulse head. This head can be used in mining for drilling holes and breaking rocks. The design of the head was developed based on computer simulations, which made it possible to learn the mechanism of impulse shaping inside the head. Tests of the water jet produced in the self-excited pulsation head showed the occurrence of periodic changes in its internal structure and pulsation frequency. A significant increase in the dynamic stream pressures was demonstrated for the head working in the water environment compared to the head working in the air environment For example, for nominal medium and highest pressures, this increase is up to 82%, while for the lowest pressures (10 MPa), the pressure force values increase by 46%. It was found that an increase in the nominal water pressure causes a decrease in the frequency of hydro...
Mechanik, 2016
Przedstawiono wyniki badań zużycia promieniowego nowych narzędzi ściernych-w porównaniu z konwenc... more Przedstawiono wyniki badań zużycia promieniowego nowych narzędzi ściernych-w porównaniu z konwencjonalnymi narzędziami ściernymi-w procesie szlifowania stopu tytanu Grade 5. Badano dwa rodzaje narzędzi: narzędzia ścierne zawierające agregaty zbudowane z ziaren elektrokorundu szlachetnego oraz ściernice o twardości M i L, zawierające różne kompozycje mikroagregatów z ziarnami elektrokorundu i mikroagregatów z ziarnami węglika krzemu. Zużycie promieniowe ściernic wyznaczono z wykorzystaniem skanera 3D Atos Triple Scan.
Materials
Modeling of material displacements in the microcutting zone is complex due to the number and inte... more Modeling of material displacements in the microcutting zone is complex due to the number and interdependence of factors affecting the results of the process. An important problem in the modeling process is the selection of the constitutive model and its parameters, which will correctly describe the properties of the material under the conditions of triaxial compression, which is characteristic for the areas of the contact zone of the blade and the processed material in abrasive machining processes. The aim of the work was to develop computer models (with the use of the finite element method) of the microcutting process with a single abrasive grain, which were verified with the results of experimental tests. The paper presents the methodology of modeling the processes of microcutting with abrasive grains, whose geometrical models were created based on optical scanning methods. Observations of the microcutting process were carried out with the use of a high-speed camera and an optical...
Materials
The present paper covers the possible ways to fabricate advanced porous coatings that are enriche... more The present paper covers the possible ways to fabricate advanced porous coatings that are enriched in copper on a titanium substrate through Direct Current Plasma Electrolytic Oxidation (DC-PEO) with voltage control, in electrolytes made of concentrated orthophosphoric acid with the addition of copper(II) nitrate(V) trihydrate. In these studies, solutions containing from 0 to 650 g salt per 1 dm3 of acid and anodic voltages from 450 V up to 650 V were used. The obtained coatings featuring variable porosity could be best defined by the three-dimensional (3D) parameter Sz, which lies in the range 9.72 to 45.18 μm. The use of copper(II) nitrate(V) trihydrate in the electrolyte, resulted, for all cases, in the incorporation of the two oxidation forms, i.e., Cu+ and Cu2+ into the coatings. Detailed X-Ray Photoelectron Spectroscopy (XPS) studies layers allowed for stating that the percentage of copper in the surface layer of the obtained coatings was in the range of 0.24 at% to 2.59 at%. ...
Materials
To fabricate porous copper coatings on titanium, we used the process of plasma electrolytic oxida... more To fabricate porous copper coatings on titanium, we used the process of plasma electrolytic oxidation (PEO) with voltage control. For all experiments, the three-phase step-up transformer with six-diode Graetz bridge was used. The voltage and the amount of salt used in the electrolyte were determined so as to obtain porous coatings. Within the framework of this study, the PEO process was carried out at a voltage of 450 VRMS in four electrolytes containing the salt as copper(II) nitrate(V) trihydrate. Moreover, we showed that the content of salt in the electrolyte needed to obtain a porous PEO coating was in the range 300–600 g/dm3. After exceeding this amount of salts in the electrolyte, some inclusions on the sample surface were observed. It is worth noting that this limitation of the amount of salts in the electrolyte was not connected with the maximum solubility of copper(II) nitrate(V) trihydrate in the concentrated (85%) orthophosphoric acid. To characterize the obtained coating...
Mechanik
In order to determine the micro-finishing abilities of diamond abrasive films, surface topography... more In order to determine the micro-finishing abilities of diamond abrasive films, surface topography was analyzed using confocal microscopy OLS 4000 Olympus. In the analysis of stereometric features of the abrasive surface, it was considered that during the micro-finishing process the abrasive surface is pressed against the workpiece. The procedure for determining the changes in topography of the film surface in the treatment area was developed as a result of elastic deformations of the film carrier, the grain binding binder and the pressure roller. New parameters for the activity of abrasive grains were developed and the values of grain hollows, depending on the pressure value in the machining zone and the nominal size of the grain (3, 9, 15, 30 μm) were determined.
International Journal of Applied Mechanics and Engineering
The article presents a stability assessment method of the mobile crane handling system based on t... more The article presents a stability assessment method of the mobile crane handling system based on the safety indicator values that were accepted as the trajectory optimization criterion. With the use of the mathematical model built and the model built in the integrated CAD/CAE environment, analyses were conducted of the displacements of the mass centre of the crane system, reactions of the outrigger system, stabilizing and overturning torques that act on the crane as well as the safety indicator values for the given movement trajectories of the crane working elements.
Metals
In the paper, the effect of voltage increase (from 500 V DC up to 650 V DC) on the structure and ... more In the paper, the effect of voltage increase (from 500 V DC up to 650 V DC) on the structure and chemical composition of the porous coating on titanium made by Plasma Electrolytic Oxidation is presented. Phosphates-based coatings enriched with calcium, magnesium, zinc, and copper in electrolyte based on 1 L of 85% concentrated H 3 PO 4 , with additions of Ca(NO 3) 2 •4H 2 O, and Mg(NO 3) 2 •6H 2 O, and Zn(NO 3) 2 •6H 2 O, and Cu(NO 3) 2 •3H 2 O, are described. The morphology and chemical and phase composition are evaluated using SEM, EDS, XRD, XPS, GDOES, and CLSM. Based on these analyses, it was found that PEO coatings are porous and enriched with calcium, magnesium, zinc and copper. They consist mainly of the amorphous phase, which is more visible for higher voltages; this is correlated with an increase in the total PEO coating thickness (the higher the voltage, the thicker the PEO coating). However, for 650 V DC , an amorphous phase and titanium substrate were also recorded, with a signal from Ti 2 P 2 O 7 crystalline that was not observed for lower voltages. It was also found that all obtained coatings may be divided into three sub-layers, i.e., porous, semiporous, and transitional.
Die Naturwissenschaften, 2016
Previous studies on preferences of phoretic deutonymphs of Uropodina for attachment sites have sh... more Previous studies on preferences of phoretic deutonymphs of Uropodina for attachment sites have shown that they frequently select smooth and hydrophobic surfaces. The aim of our study was to provide the detailed morphological and topographical characteristics of beetle body surfaces to which deutonymphs frequently attach and to verify how the presence of setae and surface sculpture affects deutonymph attachment. The study was conducted on Uropoda orbicularis (Müller, 1776) and its common beetle carriers: Aphodius prodromus (Brahm, 1790), Aphodius fimetarius (Linnaeus, 1758), Onthophagus nuchicornis (Linnaeus, 1758) and Margarinotus carbonarius (Hoffmann, 1803). Morphology and topography of elytra, femora, propygidia and pygidia of beetles were analysed mainly using SEM methods supported with CLSM and AFM techniques. The hypothesis that deutonymphs may attach to surfaces covered with setae, if seta density is low enough not to disturb mite movement, was tested. The study revealed that...
Metrology and Measurement Systems
Analysis of the shape and location of abrasive grain tips as well as their changes during the gri... more Analysis of the shape and location of abrasive grain tips as well as their changes during the grinding process, is the basis for forecasting the machining process results. This paper presents a methodology of using the watershed segmentation in identifying abrasive grains on the abrasive tool active surface. Some abrasive grain tips were selected to minimize the errors of detecting many tips on a single abrasive grain. The abrasive grains, singled out as a result of the watershed segmentation, were then analyzed to determine their geometric parameters. Moreover, the statistical parameters describing their locations on the abrasive tool active surface and the parameters characterizing intergranular spaces were determined.
Revue D Automatique Et De Productique Appliquees, 1995
Streszczenie: W artykule przedstawiono modelowanie procesu mikroskrawania materiałów trudnoskrawa... more Streszczenie: W artykule przedstawiono modelowanie procesu mikroskrawania materiałów trudnoskrawalnych metodą elementów skończonych w Solwerze LS-DYNA. Przedstawiono proces modelowania i dobierania zmiennych do modelu. Opracowany model numeryczny zweryfikowany doświadczalnie pozwolił analizować cząstki materiału w ruchu stycznym do powierzchni ostrza wraz z oddziaływaniem na nią cząstek sąsiednich, tych stykających się z powierzchnią ostrza jak również tych które bezpośrednio styku nie mają. Artykuł przedstawia wyniki procesu symulacji metodą elementów skończonych z uwzględnieniem zmian temperatury w strefie powstawania wióra.
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Papers by Wojciech Kacalak