The surface geometrical structure research of ceramic friction elements of hip joint endoprosthesis

W referacie przedstawiono zasady kształtowania struktury geometrycznej powierzchni elementów endoprotez (głów) wykonanych z mono- i polikrystalicznych materiałów ceramicznych. Przytoczono wymagania odnoszące się do biomateriałów, elementów endoprotezy stawu biodrowego oraz przeprowadzania badań struktury geometrycznej ich powierzchni (błąd kształtu i chropowatość). Uzyskane wyniki pomiarów błędów kształtu (odchyłki okrągłości) oraz chropowatości poddano analizie, na podstawie której wysunięto wnioski dotyczące kształtowania głów endoprotez stawu biodrowego.The paper presents the rules of forming the surface geometrical structure for endoprosthesis elements (femoral head) made of mono and polycrystalline ceramic materials. The requirements for biomaterials and elements of hip joint endoprosthesis were described. The surface geometrical structure research (shape deviations and roughness) was discussed. The results of shape deviations (departure from roundness) and surface roughness measurements were analysed. On the basis of the analysis, conclusions on the manufacturing process of the head of hip joint endoprosthesis were drawn

Koincydencja technologii i topografii powierzchni elementów sferycznych kształtowanych w procesie obróbki precyzyjnej

The paper presents issues concerning the surface layer and the changes in surface topography with respect to spherical elements at the subsequent stages of manufacturing process. Special attention was paid to the forming of surface topography in precision machining processes (preliminary grinding, precision grinding, lapping with polishing). The subjects of research and analysis were spherical elements made of a biomaterial, i.e. titanium alloy (Ti-6.5Al-l.3Si-2Zr). The surfaces of the studied components shaped during the subsequent operations of abrasive machining processes were measured using a coordinate measurement machine (CMM) and a white light interferometer (WLI). Based on the obtained results, the changes in the surface topography of metallic spherical elements brought about during the subsequent operations of precision machining processes were assessed. In addition to this, functional properties of these surfaces were identified.W pracy przedstawiono zagadnienia dotyczące warstwy wierzchniej oraz zmian topografii powierzchni elementów sferycznych podczas kolejnych etapów procesu wytwarzania. Szczególną uwagę zwrócono na kształtowanie topografii powierzchni w obróbce precyzyjnej (szlifowanie wstępne, szlifowanie precyzyjne, docieranie z polerowaniem). Przedmiotem badań oraz analiz były elementy o zarysie sferycznym wykonane z biomateriału – stopu tytanu (Ti-6.5Al-1.3Si-2Zr). Powierzchnie elementów ukształtowane w kolejnych etapach procesu obróbki ściernej zostały zbadane z wykorzystaniem współrzędnościowej maszyny pomiarowej (Coordinate Measurement Machine – CMM) oraz interferometru optycznego (White Light Intereferometry – WLI). Na podstawie otrzymanych wyników oceniono proces zmian topografii powierzchni metalowych elementów sferycznych podczas kolejnych etapów procesu obróbki precyzyjnej oraz określono potencjalne właściwości użytkowe tych powierzchni

Surface geometric structure created by the electrical discharge machining process

Obróbka elektroerozyjna, należąca do tzw. niekonwencjonalnych metod obróbki materiałów, znalazła szerokie zastosowanie w kształtowaniu elementów wykonanych z materiałów trudnoskrawalnych oraz o złożonej geometrii. W pracy przedstawiono ogólną charakterystykę obróbki elektroerozyjnej. Analizie (ilościowej i jakościowej) poddano wyniki badań (mikroskop optyczny, elektronowy mikroskop skaningowy, profilometr) struktury geometrycznej powierzchni ukonstytuowanej w procesie obróbki elektroerozyjnej. Stwierdzono istotny wpływ parametrów obróbki na ukształtowanie powierzchni oraz jej jakość technologiczną.Electrical discharge machining, which belongs to the non-conventional group of machining methods is widely used for manufacturing elements made of hard materials and those having a complicated geometry. The paper gives an overview of electrical discharge machining. The author has conducted research (quantitative and qualitative) into the results of the surface geometric structure created by the electrical discharge machining process. For analysis purposes, an optical microscope, a scanning electron microscope, and a profilometer were used. It has been found that machining parameters have a significant influence on the shape and technological quality of a surface

The influence of the chosen parameters of electric discharge machining on the surface features

Tematyka obejmuje zagadnienia z zakresu niekonwencjonalnych metod kształtowania materiałów trudnoskrawalnych – obróbki elektroerozyjnej EDM. W pracy przedstawiono wyniki badań, na podstawie których określono wpływ wybranych parametrów obróbki (energii pojedynczego impulsu Ei) na strukturę geometryczną powierzchni obrobionej, w tym na kształt i rozmiary jej cech (kratery, wgłębienia, nadtopienia, wypływki, pęknięcia, sferoidy).The paper covers the issues concerning Electric Discharge Machining (EDM), a non-conventional method employed to machine hard materials. The research results are presented, on the basis of which the influence of the chosen EDM parameters (single discharge energy Ei) on the surface geometric structure, including the shape and the size of its features (crater, cavity, remelted area, flash, crack, spheroid), are then discussed

Assessment of Free-Form Surfaces’ Reconstruction Accuracy

The paper presents the problem of assessing the accuracy of reconstructing free-form surfaces in the CMM/CAD/CAM/CNC systems. The system structure comprises a coordinate measuring machine (CMM) PMM 12106 equipped with a contact scanning probe, a 3-axis Arrow 500 Vertical Machining Center, QUINDOS software and Catia software. For the purpose of surface digitalization, a radius correction algorithm was developed. The surface reconstructing errors for the presented system were assessed and analysed with respect to offset points. The accuracy assessment exhibit error values in the reconstruction of a free-form surface in a range of ± 0.02 mm, which, as it is shown by the analysis, result from a systematic error

The analysis of the tribological processes occurring in the socket-and-ball friction pair of a hip joint endoprosthesis

W pracy przedstawiono staw biodrowy jako idealne biołożysko. Omówiono przyczyny uszkodzenia naturalnego stawu biodrowego człowieka oraz sposoby przywrócenia utraconych funkcji, w tym alloplastykę stawów. W części badawczo- -analitycznej pracy omówiono przyczyny obniżenia trwałości endoprotez stawu biodrowego w oparciu obadania własne in vitro. Przedmiotem badań było skojarzenie panewka–główka endoprotezy stawu biodrowego. Powierzchnie badanych elementów zostały przygotowane zgodnie z wytycznymi norm. Badania tribologiczne przeprowadzono w otoczeniu płynu Ringera. Badania stanu powierzchni przed i po eksploatacji przeprowadzono na trzech urządzeniach: współrzędnościowej maszynie pomiarowej, mikroskopie interferometrycznym oraz skaningowym mikroskopie elektronowym. Wyniki przeanalizowano pod kątem procesów tribologicznych (mechanizmów zużycia) występujących w skojarzeniu polimerowa panewka–metalowa główka endoprotezy stawu biodrowego.The paper presents a hip joint as an ideal system. The causes of the damage to a natural human hip joint and the ways of restoring its lost functions along with hip joint alloplasty are discussed. In the research part of this paper, based on in vitro study, the reasons for the loss of artificial hip joint durability are described. The subject of the research was the socket-andball friction pair, making the elements of a hip joint endoprosthesis. The surfaces of the analysed samples were prepared in accordance with the guidelines of the standards. The tribological tests were conducted in the environment of Ringer's solution. The examination of the surface topography before and after tribological tests was carried out with three units: a coordinate measurement machine, white light interferometry, and a scanning electron microscope. The results were analysed in terms of tribological processes (wear mechanisms) occurring in the friction pair consisting of the polymer socket and the metal head of a hip joint endoprosthesis

Product Quality Assessment – Measurement and Analysis of Surface Topography

This paper concerns the issues of measurement techniques, analysis and assessment of the machined surface geometric structure. The aim of this work was to show the application of surface analysis in diagnosing the causes of discrepancies occurring in the manufacturing process, which may result from ill-matched (poorly fitting) process parameters. An appropriate system of control and interpretation of results may allow early reaction to unfavorable trends (for example blunting of the tool) and prevention of undesirable defects. The subject of research was a waste basket used in the construction of retaining sewer systems. In this paper, the quality of the waste basket as well as its manufacturing process were analyzed and assessed. The research was carried out with the use of three measurement stands, i.e. optical microscopy (OM), scanning electron microscopy (SEM) and white light interferometer (WLI). The surface analysis proved to be important from the viewpoint of outlining the production process as well as improving the product quality. The software used for topographical analysis appeared to be significant for the success of the analysis, providing notable economic effects, namely the lack of defects

Measurement techniques used for analysis of the geometric structure of machined surfaces

The quality of machined surfaces, resulting from the manufacturing process and conditioning their functionality, is determined by the surface geometric structure (SGS). There is a close relationship between surface properties, shape, qualitative imagining of the surface topography, technique and technology employed for machining purposes [1, 2]. If a given surface is to have practical applications in engineering, the correct technological process needs to be chosen. In the paper, various techniques used for measuring the surface geometric structure were described. The results of the study, which were obtained from different measuring devices like Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and Optical Interferometer (WLI), were presented. Optical Microscopy (OM) was shown as a helpful device to analyse some aspects of surface topography. Each measuring technique provided different, yet complementary data on the topography of the machined surfaces. Owing to this, a full characterization of the geometric surface structure of the machined surfaces was enabled, including surface properties resulting from the applied technological process. Based on the measurements made, the characteristics of chosen devices (measurement techniques) were defined with an indication of how they can be applied to the analysis of the surface geometric structure (SGS). The devices which are considered to give the best view of examined surfaces and allow a thorough analysis of their irregularities were then indicated

Product quality assessment – measurement and analysis of surface topography

This paper concerns the issues of measurement techniques, analysis and assessment of the machined surface geometric structure. The aim of this work was to show the application of surface analysis in diagnosing the causes of discrepancies occurring in the manufacturing process, which may result from ill-matched (poorly fitting) process parameters. An appropriate system of control and interpretation of results may allow early reaction to unfavorable trends (for example blunting of the tool) and prevention of undesirable defects. The subject of research was a waste basket used in the construction of retaining sewer systems. In this paper, the quality of the waste basket as well as its manufacturing process were analyzed and assessed. The research was carried out with the use of three measurement stands, i.e. optical microscopy (OM), scanning electron microscopy (SEM) and white light interferometer (WLI). The surface analysis proved to be important from the viewpoint of outlining the production process as well as improving the product quality. The software used for topographical analysis appeared to be significant for the success of the analysis, providing notable economic effects, namely the lack of defects

The tribological research of materials for use in a medical technique

W pracy przedstawiono procedurę przeprowadzania badań technologicznych nowych materiałów przeznaczanych do zastosowania w technice medycznej, w szczególności na implanty stawów. Przedmiotem badań oraz analiz było przykładowe skojarzenie materiałowe: metal–polimer, w węzłach tarcia: trzpień–płytka oraz panewka–główka. Powierzchnie badanych elementów zostały ukształtowane oraz przygotowane zgodnie z wytycznymi norm. Modelowe i symulacyjne badania tribologiczne przeprowadzono w otoczeniu płynu Ringera. Wyznaczono charakterystyki tribologiczne oraz przeprowadzono analizę korelacji pomiędzy czynnikami technologicznymi (cechami geometrycznymi) ukonstytuowanymi w procesie wytwarzania a charakterystykami tribologicznymi (współczynnik tarcia/moment tarcia) oraz ukonstytuowaną w trakcie eksploatacji powierzchnią (produkty zużycia).The paper presents the procedure for technological research of new materials to be applied in a medical technique, especially for hip joint implants. The subject of the research and analysis was the metal-polymer combination in the plate-on-pin and ball-and-socket friction pairs. The surfaces of the tested components were shaped and prepared in accordance with the relevant guidelines of the standards. Tribological tests (modelling and simulating) were carried out using Ringer’s fluid. Tribological characteristics were determined. The correlation between technology factors (geometric features) constituted in the manufacturing process and tribological characteristics (friction coefficient, friction torque) as well as the surface shaped during operation (wear products) were established