The development of industry is determined by the use of modern materials in the production of parts and equipment. In recent years, there has been a significant increase in the use of nickel-based superalloys in the aerospace, energy and space industries. Due to their properties, these alloys belong to the group of materials hard-to-machine with conventional methods. One of the non-conventional manufacturing technologies that allow the machining of geometrically complex parts from nickel-based superalloys is electrical discharge machining. The article presents the results of experimental investigations of the impact of EDM parameters on the surfaces roughness and the material removal rate. Based on the results of empirical research, mathematical models of the EDM process were developed, which allow for the selection of the most favourable processing parameters for the expected values of the surface roughness Sa and the material removal rate.
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Przeprowadzono badania skutków modyfikacji struktury CPS w zakresie intensyfikacji wydajności procesu szlifowania, z jednoczesnym spełnieniem standardowych wymagań odnośnie do chropowatości powierzchni. Elementami modyfikacji są modelowo określone udziały 2 granulacji ziaren SiC oraz 2 granulacji ziaren CrA w ściernicach trzpieniowych ze spoiwem ceramicznym do szlifowania czołowego.
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The investigation has been carried out into the effect of modifying the active wheel surface structure in view of enhancing productivity of the grinding process. This undertaking should be consistent with standard surface roughness requirements. This modification involves the model-based shares of the two SiC grain grit sizes and two CrA grit sizes in the grinding pins with ceramic bond for the face grinding process.
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Przedstawiono dotychczas opracowane modele matematyczne procesu toczenia wzdłużnego tytanu WT3-1 w postaci wykładniczej i wielomianowej. Modele doświadczalne opracowano statystycznie za pomocą programów krokowej regresji wielokrotnej. Badania wykonano zgodnie z zasadami planowania eksperymentów.
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Mathematical models for longitudinal turning process of the titanium alloy WT3-1 were presented in this paper, both in the exponential and the polynomial form. The experimental design and the multiple stepwise regression analysis were used to develop the mathematical models.
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Stan warstwy wierzchniej jest jednym z podstawowych zagadnień adaptacji obróbki elektroerozyjnej w wytwarzaniu części maszyn. W artykule przedstawiono wyniki badań doświadczalnych zastosowania obróbki przetłoczno-ściernej (AFM) na finalny stan struktury geometrycznej powierzchni przedmiotów po obróbce elektroerozyjnej.
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Surface layer quality after electrical discharge machining is one of the basic problems in adaptation EDM in manufacturing parts. The article present experimental investigation of application abrasive flow machining in improve surface quality after EDM.
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Przedstawiono budowę doświadczalnego modelu matematycznego procesu toczenia tytanu WT3-1, optymalizację jedno i wielokryterialną wybranych cech procesu. Zacytowano wybrane pozycje literatury, w których m.in. wskazuje się na podstawowe właściwości tytanu i jego stopów oraz charakterystykę ich obróbki.
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This article presents the experiment-based mathematical model for turning of the WT3-1 titanium, single- and multi-criterion optimization of the selected process features. The references have been cited; they include indications as to the basic properties of titanium.
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Istotnym elementem procesów wytwarzania są operacje wykończeniowe, które w wielu przypadkach decydują o właściwościach produkowanych elementów. W artykule przedstawiono przykład zastosowania obróbki przetłoczno-ściernej do usuwania mikrozadziorów i wygładzania powierzchni narzędzi.
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Important elements in the manufacturing process are finishing operations, which determine the final properties of the manufacturing parts. The article presents the results of application of abrasive flow machining in the removal of micro-burrs and surface smoothing in tools.
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Przedstawiono możliwości strumieniowo ściernej obróbki wykończeniowej elementów wytwarzanych wycinaniem elektroerozyjnym (WEDM). Wykorzystano system pneumatyczny do formowania strumienia z mikrokulkami ceramicznymi, którego skuteczność obróbkową testowano przy usuwaniu warstwy tlenków z powierzchni po WEDM. Dokonano oceny wpływu parametrów obróbki na chropowatość i dokładność kształtową tych powierzchni.
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The potential of abrasive blast machining for finishing the parts after the wire electrical discharge machining (WEDM) was presented. The pneumatic system was used for forming a stream of glass micro-balls. Its effectiveness was tested when removing the oxide layer from the WEDM surface. The influence of the process parameters on surface roughness and dimensional accuracy was discussed.
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W artykule przedstawiono analizę struktury metalograficznej po obróbce elektroerozyjnej stali HTCS 150. Określono wpływ parametrów obróbki tj. natężenia prądu wyładowania I, oraz czasu impulsu Ton na wybrane składowe warstwy wierzchnie stali HTSC 150.
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This paper presents an analysis of surface layers properties after EDM steel HTCS 150. Experimental studies were conducted, determined the influence of parameters: discharge current I and the pulse time ton on selected components of the surface layers steel HTSC 150.
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W artykule scharakteryzowano procesy obróbki EDM z użyciem proszków w dielektryku. Wykonano badania z proszkami metali; Sn, Fe, Cu i opracowano modele matematyczne tych procesów. Dokonano polioptymalizacji badanych procesów z uwagi na wydajność obróbki, czas obróbki i parametr chropowatości Ra, Przedstawiono wyniki obliczeń oraz wnioski.
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The EDM process described in this paper has been carried out with the electrical conductive powder in dielectric. The powders of Sb, Fe and Cu were used. The mathematical model of this process wear has been developed. The poly-optimization method has been used in view of productivity, time of machining and parameter of surface roughness Ra.
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Stopy na bazie niklu (np. Inconel 718) są często wykorzystywane w przemyśle lotniczym ze względu na dobre właściwości mechaniczne oraz chemiczne przy pracy w podwyższonej temperaturze. Ze względu na warunki, w jakich pracują elementy wykonane z omawianego stopu, istotny jest wynikowy stan warstwy wierzchniej obrabianych przedmiotów. W artykule przestawiono wpływ parametrów procesu WEDM na konstytuowanie warstwy wierzchniej dla Inconelu 718.
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Inconel 718 C is widely used in the aerospace industry due to their good mechanical and chemical properties at high temperatures. This material is especially used as turbine disk, blades, combustors, etc. These parts are working in difficult conditions that very important is the state of the surface layer of the workpiece after WEDM process. The paper presents an analysis of the influence of cutting parameters on selected components of the surface layer after WEDM.
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Artykuł zawiera ostatnie informacje z zakresu obróbki elektrochemicznej (ECM) zebrane z doniesień naukowych ośrodków interesujących się tymi zagadnieniami oraz doniesień z zakładów produkujących obrabiarki elektrochemiczne. Główne zagadnienia poruszane z tego zakresu, to wytwarzanie monolitycznych tarcz turbin silników lotniczych (blisk) z łopatkami, a także technologia usuwania zadziorów metodą ECM.
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The paper includes recent information on the Electrochemical Machining (ECM) which was accumulated basing on the scientific newsletters issued by the research centers interested in such problems and the newsletters of electrochemical machine manufacturers. The major problems which were described are concentrated on the monolithic aircraft engine turbine wheels (blisks) with the integrated blades and on the method of the ECM deburring.
We present density functional theory (DFT) calculation results of krypton and xenon atoms interaction on the surface of uranium dioxide single crystal. A pseudo-potential approach in the generalised gradient approximation (GGA) was applied using the ABINIT program package. To compute the unit cell parameters, the 25 atom super-cell was chosen. It has been revealed that close to the surface of a potential well is formed for xenon and krypton atom due to its interaction with the atoms of oxygen and uranium. Depth and shape of the well is the subject of ab initio calculations in adiabatic approximation. The calculations were performed both for the case of oxygenic and metallic surfaces. It has been shown that the potential well for the oxygenic surface is deeper than for the metallic surface. The thermal stability of immobilising the atoms of krypton and xenon in the potential wells were evaluated. The results are shown in graphs.
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The technique of Young’s modulus variation in the finite element is not spread in biomechanics. Our future goal is to adapt this technique to bone tissue strength calculations. The aim of this paper is to present the necessary studies of the element’s integration method that takes into account changes in material properties. For research purposes, a virtual sample with the size and distribution of mechanical properties similar to these in a human femoral wall, was used. WinPython, an environment of Python programming language was used to perform simulations. Results with the proposed element were compared with ANSYS element PLANE42 (with constant Young modulus). The modeled sample was calculated with five different integration methods at five different mesh densities. Considered integration methods showed a very high correlation of results. Two-point Gauss Quadrature Rule proved to be the most advantageous. Results obtained by this method deviate only slightly from the pattern, while the computing time was significantly lower than others. Performed studies have shown that accuracy of the solution depends largely on the mesh density of the sample. Application of the simplest integration method in combination with four times coarser mesh density than in ANSYS with a standard component still allowed to obtain better results.
The methods of the grinding process efficiency evaluation have been presented in this paper basing upon the temperature in the workpiece tool contact area. The technique of determining this temperature has also been given as a combination of analytical and experimental process. These are especially useful by properties and phase transformation investigations in the metastable austenite steels.
We present quantum-mechanical evaluation of helium diffusion coefficient in the crystalline UO2 and ThO2. Parameters assignment of Schrödinger’s equation were done using the crystal field potentials which were obtained applying the density functional theory (DFT). “Ab initio” calculations were performed using the Wien2k program package. To compute the unit cell parameters the 13 atom super-cell was chosen. Applying two-site model we evaluated the time for an over-barrier jump and diffusion of interstitial He. The obtained values for diffusion coefficient are compared with the experimentally obtained values and with the theoretical values of other authors. In addition, it is simultaneously shown that helium diffusion in these materials is a quantum diffusion.
We present density functional theory (DFT) calculation results of xenon atom interaction with the surface of uranium dioxide single crystal. A pseudo-potential approach in the generalized gradient approximation (GGA) was applied using the ABINIT program package. It has been revealed that close to the surface a potential well is formed for xenon atom due to its interaction with the atoms of oxygen and uranium. Depth and shape of the well is the subject of “ab initio” calculations. The calculations were performed both for the case of oxygenic and metallic surfaces. It has been shown, that the potential well for the oxygenic surface is deeper than for the metallic surface.
Modelowanie przepływu dielektryka w szczelinie międzyelektrodowej. Dobór siatki elementów objętościowych. Analiza wpływu siatki elementów na wyniki modelowania.
The valence electron density distribution of krypton and xenon located in the oxygen vacancy and in its nearest neighbourhood was performed by application of the method “ab initio”. The results are presented on the graphs. The bonding energies of krypton and xenon in the uranium dioxide crystal lattice were calculated. It was found also that krypton and xenon cause a local increase of UO1.75Xe0.25 and UO1.75Kr0.25 unit cell and cause its deformation what is presented in tables. The force constants of krypton and xenon were also assigned what gives evidence about the strong bond of krypton and xenon with the UO1.75Xe0.25 and UO1.75Kr0.25 single crystal lattice. Obtained results are compared with the analogical studies of He atom incorporation into UO2 single crystal lattice.
Density functional theory (DFT) results of calculations of the mixed thorium and uranium dioxide Th1-xUxO2 for the following mole ratio x = 0, 0.25, 0.75 and 1 are presented and discussed. "Ab initio" calculations were performed using the Wien2k program package. To compute the unit cell parameters the 12 atom super-cell were chosen. The lattice parameters were calculated through minimization of the total energy by the change of lattice parameters and atom displacement within the unit cell. Calculations were performed for five different exchange energy approximations EXC with and without corrective orbital potential U, and obtained lattice constants are presented graphically and compared with experimental data. It is established that the initially assumed oxygen location within the unit cell plus or minus 0.25 of the mixed compounds are not their equilibrium positions. The oxygen atoms within the unit cell undergo dislocation in the (111) direction. So, the distances oxygen-uranium are smaller than the distances oxygen-thorium. The change of local structure is presented graphically and appropriate parameters values are given in Table. The bulk modulus and the cohesive properties are also counted and shown graphically.
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