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PL
Bezspoiwowy węglik wolframu (WC) jest kluczowym materiałem na formy i matryce, ponieważ ma zbliżone do diamentu właściwości pod względem twardości i współczynnika rozszerzalności. Te same właściwości są jednak odpowiedzialne za złą szlifowalność WC. W artykule przedstawiono niskotemperaturową metodę nanosmarowania z wykorzystaniem rurki wirowej, która zapewnia zwiększenie wymiany ciepła.
2
Content available remote Docierarki do płaszczyzn. Cz. II. Docierarki dwutarczowe
PL
Współcześnie docieranie można zaliczyć do podstawowych sposobów bardzo dokładnej obróbki ściernej. Nie występują ograniczenia w zakresie rodzaju, a także twardości obrabianego materiału.
3
Content available remote Jakość warstwy wierzchniej przy szybkościowym szlifowaniu stopu Al6061T6
PL
Materiały o wysokiej ciągliwości często stwarzają problemy podczas szlifowania szybkościowego. Wysoka prędkość odkształcenia powoduje nie tylko kruchość materiału, ale także uszkodzenia warstwy wierzchniej. Tu przedstawiono wyniki badania integralności warstwy wierzchniej i mechanizmów usuwania materiału przy szlifowaniu kutego stopu Al6061T6 z prędkością w zakresie: 30,4÷307,0 m/s.
EN
Machined subsurface and burr of nickel-based single-crystal superalloys (SXs) were identified as a key factor to the aero-engine industrial requirements concerning high service performance and the precision of edge geometry, in particular the finishing operations as grinding. To clarify subsurface deformation behaviors and the mechanisms of burr formation when grinding SXs, first, the present investigation predicted slip stresses acting on slip systems in workpiece subsurface under grinding based on the theory of resolved shear stress in single crystal, and correlated theoretical possible slip traces with experimental observed slip band systems. Second, grinding experiments on nickel-based SXs with [00-1]/[010], [11-3]/[332], [-110]/[111] and [-1-1-1]/[-110] orientations were performed to determine the anisotropy deformational behaviors of workpiece subsurface. Lastly, the unreported free surface of burr was adopted to investigate the formation mechanisms for side burrs and exit burrs during grinding. Results show that subsurface deformation patterns present anisotropy and resolved shear stress contribute to slip in nickel-based SXs. High shear density layers/zones consisting of interacted slip bands are found in grinding-induced sub-surfaces. Slip induced plasticity is the dominant deformation mechanism in the formation process of side burrs and exit burrs in grinding of nickel-based SXs.
PL
W artykule przedstawiono dalsze rezultaty badań eksperymentalnych dotyczących wpływu wybranych czynników procesu szlifowania na stan powierzchni elementów obrotowych. Opis pierwszej części zawarty jest w numerze 3/2022. W tej części analizowano wpływ granulacji ziaren ścierniwa na chropowatość obrabianych powierzchni, a także związek między parametrami obciągania ściernicy a stanem powierzchni po obróbce. Stwierdzono zróżnicowaną istotność tych czynności.
EN
In the paper, further carried out experimental studies on the effects of selected grinding process factors on surface properties were presented. The description of the first part is given in No 3/2022. This section investigations the effects of granulation of abrasive grains on the surface roughness of the treated surfaces were contained. The relationship between the parameters of the grinding wheel dressing and the condition of the surface after machining were presented too. Different relevance of these factors was found.
PL
W artykule przedstawiono analizę czynników determinujących rezultaty obróbki szlifowaniem powierzchni elementów maszyn. Przedstawiono także rezultaty badań eksperymentalnych dotyczących wpływu wybranych czynników tego procesu na stan powierzchni szlifowanych elementów obrotowych.
EN
In this paper the factors that determine the results of the grinding of machine elements were analyzed. Experimental research on the effects of selected process factors on the surface properties (its roughness) of rotating components were also presented.
EN
A properly implemented strategy regarding the planer knife regeneration process, may not only restore the original cutting ability of the tool, but even increase its operational quality, including its durability for industrial woodworking processes. This article presents experimental results and discussion in respect of sharpening planer knives with cubic boron nitride grinding wheels. Both the grinding conditions and machining surface quality were analyzed. Application of improper size or loads of abrasive grains may lead to the appearance of grinding burns on a machined surface, or result in a surface with cracks and grooves. The results of the measurements carried out indicate that surfaces with reduced values of roughness and waviness parameters can be obtained, even up to 22% (as in the case of the reduced peak height parameter, Spk) in relation to new knives, prepared at a factory. The value of St and Sds parameters are almost the same as reference knife (deviation up to 3%). Due to machining marks, the total waviness exceeds 33%. Our research also shows that due to the technological quality of the knife surfaces, it is beneficial to use CBN grains with a low depth of cut (ae no more than 0.02 mm), but a moderate or high feed rate (the best choice is about 470 mm/min for vft). Presented results constitute an important know-how for the grinding process with the use of grinders used by operators (like WEINIG Rondamat 980) during the sharpening of planer cutter heads in the wood industry.
EN
In this work, four types of surfaces were prepared as follows: untreated one, dry grinding (DG), wet grinding (WG) and minimum quantity lubrication grinding (MQLG) for Ni-based single crystal superalloy. The effects of grinding conditions on the surface roughness and microstructure evolution were studied. Dry sliding tests of ground surfaces were carried out at room temperature. Through the quantitative characterization of the wear rate, the area, width and depth of the worn profiles, the friction and wear mechanism of superalloy prepared by different grinding conditions were analyzed. The results show that the MQLG surface with low surface roughness and work hardening behavior has the best wear resistance. The element transfer behavior from the GCr15 ball to the worn surface was detected by EDS analysis. The wear type is mainly abrasive wear, accompanied by slight adhesive wear and oxidation wear. It is shown that high-quality surface with nanocrystalline and high density dislocation structure produced by MQLG improves the tribological properties of superalloy, which provide theoretical guidance for the surface machining of single crystal blade to reduce fretting wear.
EN
This article proposes a method for grinding coal based on the use of the energy of a pulsed shock wave resulting from a spark electric discharge in a liquid. The main purpose of the scientific work is the development of an electric pulse device for producing coal powder, the main component of coal-water fuel. The diameter of the initial coal fraction averaged 3 mm, and the size of the resulting product was 250 μm. To achieve this goal, the dependence of the length of a metal rod electrode (positive electrode) on the length and diameter of its insulation is investigated. Various variants of the shape of the base (bottom) of the device acting as a negative electrode are considered, and an effective variant based on the results of coal grinding is proposed. An experimental electric pulse installation is described, the degree of coal grinding is determined depending on the geometric parameters. The optimal characteristics of the obtained coal powder have been established.
10
PL
W celu redukcji negatywnego oddziaływania na środowisko i zwiększenia wydajności wielu producentów zastępuje się ciecze obróbkowe do szlifowania na bazie oleju cieczami opartymi na wodzie. Nadal jednak do dogładzania oscylacyjnego używa się cieczy olejowych. Tu przedstawiono badanie możliwości ich zastąpienia przez nową, wodną ciecz obróbkową.
EN
The comprehensive knowledge of the applications of nano-fluids for hybrid machining processes assisted by liquid media, which, in general, are applied in MQL systems is presented. In the first part of the article properties of nano-additives, which are added to base cutting fluids (such as vegetable and mineral oils and emulsion), and their influence on the performance of machining processes were outlined. The tribological mechanisms including rolling and plowing of the nano-particles in the contact zones, as well as resulting thermal influences were characterized. In the second part of the article, some practical examples of the possible influences of different nano-fluids on the cutting temperature, tool wear and tool life, surface roughness and surface quality are provided and discussed. It was concluded that nano-fluids with graphene and carbon nanotubes additives are very effective in improving process behaviour.
PL
Przedstawiono zwięzłe informacje na temat zastosowania nanocieczy do wspomagania hybrydowych procesów skrawania mediami ciekłymi, które zasadniczo znalazły zastosowanie w minimalnym smarowaniu/chłodzeniu MQL. W pierwszej części artykułu omówiono właściwości dodawanych do cieczy bazowych (olejów roślinnych i mineralnych oraz emulsji) nanocząstek i ich wpływ na przebieg procesu skrawania. Scharakteryzowano mechanizmy tribologiczne w strefie kontaktu i pochodne oddziaływania termiczne. W drugiej części artykułu zostaną opisane praktyczne przykłady wpływu nanocieczy na temperaturę skrawania, przebieg zużycia i trwałość ostrza oraz chropowatość i jakość powierzchni. Wykazano dużą efektywność zastosowania nanocieczy z dodatkami grafenu i nanorurek.
EN
The comprehensive knowledge of the applications of nanofluids for hybrid machining processes assisted by liquid media, which, in general, are applied in MQL systems is presented. In the first part of the article properties of nano-additives, which are added to base cutting fluids (such as vegetable and mineral oils and emulsion), and their influence on the performance of machining processes are outlined. The tribological mechanisms including rolling and plowing of the nano-particles in the contact zones, as well as resulting thermal influences are characterized. In the second part of the article, some practical examples of the possible influences of different nano-fluids on the cutting temperature, tool wear and tool life, surface roughness and surface quality will be provided and discussed. It was concluded that nano-fluids with graphene and carbon nanotubes additives are very effective in improving process behaviour.
PL
Przedstawiono zwięzłe informacje na temat zastosowania nanocieczy do wspomagania hybrydowych procesów skrawania mediami ciekłymi, które zasadniczo znalazły zastosowanie w minimalnym smarowaniu/chłodzeniu MQL. W pierwszej części artykułu omówiono właściwości dodawanych do cieczy bazowych (olejów roślinnych i mineralnych oraz emulsji) nanocząstek i ich wpływ na przebieg procesu skrawania. Scharakteryzowano mechanizmy tribologiczne w strefie kontaktu i pochodne oddziaływania termiczne. W drugiej części artykułu zostaną opisane praktyczne przykłady wpływu nanocieczy na temperaturę skrawania, przebieg zużycia i trwałość ostrza oraz chropowatość i jakość powierzchni. Wykazano dużą efektywność zastosowania nanocieczy z dodatkami grafenu i nanorurek.
EN
Nickel-based single-crystal superalloys (SXs) are used as materials for aero- and industrial gas turbine blades due to their superior high-temperature strength. However, SXs have low thermal conductivity, high hardness, and high working hardening, which significantly increase the machining difficulty. Improving machining performance has been a critical aspect that influences functional performance, including the fatigue life of the blades. In this study, preliminary comparative tests were performed for abrasive belt grinding of SXs to obtain better performance in terms of surface roughness (Ra), material removal rate (MRR) and abrasive belt wear rate (Bw). Two empirical models of the process parameters of abrasive belt grinding were established using response surface methodology (RSM), and the influences of belt speed (Vs), feed speed (Vw), and normal grinding force (Fn) on Ra and MRR were analysed. The Ra and MRR were optimized with multiple responses to balance the grinding quality and efficiency based on the desirability function method. Both the percentage error of the experiments and model prediction error are within a reasonable range of 5%. In particular, three typical crystal planes ((001), (110), and (111)) were prepared and used to study the grinding performance from the perspective of anisotropy sensitivity.
EN
In the present study, the grinding experiment of second-generation nickel-based single-crystal superalloy DD5 was carried out under different grinding parameters. The grinding force was recorded during the grinding process, and it was found that it decreased with increasing grinding speed and increased with feed speed. The microstructure evolution of ground subsurface was obtained by optical microscope (OM) and scanning electron microscope (SEM), and the elemental distribution of γ/γ' phases was investigated by energy dispersion spectrum (EDS). The results show that there are two layers different from the bulk material beneath the ground surface: (i) a white layer (WL) with no obvious structural features under limited observation scale and (ii) a severe deformed layer (SDL) with the elongated and rotated γ' phase and the narrowed γ channel. Elements segregation behavior exists in both the white layer and severe deformed layer. The grinding parameters have a great influence on the thickness of the white layer, which is due to the elemental diffusion behavior caused by intensive thermo-mechanical load. There is work hardening in the white layer, and the hardening degree aggravates with the increase in cutting speed and feed speed.
EN
The article presents the study results of electropulse grinding of amber in aqueous and alcoholic media at different amounts of supplied energy. Description of the electropulse grinding laboratory installation, the mechanism of the destruction process of amber particles and methods of statistical processing of experimental data are given. It was established that alcohol medium has a greater impact on the efficiency of crushing than water. Thus, under the same conditions of energy supply, in the aqueous medium the weighted average particle size of amber was 601:6±688:9 μm, and in an alcohol medium – 368:0±269:6 μm. In an aqueous medium, the particle size decreased to 1/13.6 of raw sample, and in an alcoholic medium to 1/22.3 of raw sample compared to the initial size of raw amber. We found that in the aqueous medium the ratio of large to small fractions is mainly the same with the coefficient of alignment of particles with a size of 1.09. In an alcoholic medium, this ratio significantly differs, with the coefficient of alignment of amber particles of a size of 1.67 with the amount of supplied energy of 125 kJ.
EN
The article presents the results of experimental research on the grinding of corundum ceramics in the pre-sintered state, with spherical diamond heads. The aim of the experiment was to determine the effect of grain size and feed rate on selected aspects of the grinding process of corundum ceramics with the use of spherical diamond heads. In the experiment, grinding wheels with a ball diameter of 3 mm and different grain sizes were used; the grain numbers were D64, D91, D126 and D181. The tests were carried out on the Ultrasonic 20 Linear machining center at a constant rotational rate of the grinding wheel n = 38,000 rpm and a grinding depth of 30 µm. The feed rate was set on 3 values: 200, 400 and 600 mm / min. During the research, the process temperature was recorded with a thermal imaging camera. The topography of grinding wheels before and after the grinding process and the topography of the ground surface were also measured. The parameters Sa and Ŝz (Ŝz= Spk+Sk+Svk) were used to characterize the grinding heads. The conducted analyses showed the dependence of the parameters Sa and Ŝz of new grinding heads on the grain size described by the quadratic function (R^(2 )≥0.94). Statistically significant changes in the parameters Sa and Ŝz on the cutting surface of the grinding wheel, which occurred as a result of its wear, were observed. There was no significant relationship between the feed rate and the wear of grinding heads, probably due to the relatively small volume of the material removed. A positive correlation between the Sa and Ŝz parameters of the ground object and the grain size was observed. The research also showed an increase in the process temperature with an increase in the feed rate and an increase in the grain size.
EN
The article concerns an investigation of 100Cr6 steel surface peripheral grinding process with glass-crystalline bonded grinding wheels. More precisely the investigation of surface roughness parameters and grinding force components in relation to different dressing overlap ratio, feed rate and grinding depths values. Seven different values of dressing overlap ratio have been used to determine influence of dressing overlap ratio to grinding force and surface roughness. After determining the stable range of dressing overlap ratio, other tests were conducted with eleven different values of feed rate and two values of grinding depth to determine how they shape the grinding force components and surface roughness parameters. The machining has been performed using a CNC surface grinding machine, together with a surface grinding wheel and up grinding strategy. Additional NI equipment was used for grinding force data acquisition. The surface roughness was assessed using two parameters (Ra, Rz). The contact measurements of surface roughness were carried out using the MarSurf PS 10 profilometer. The dresser effective width was measured with the use of AM7515MZT Dino-Lite microscope to ensure consistent values of dressing overlap ratio throughout the entire experiment. Significant impact of the dressing overlap ratios, feed rate and grinding depths on the grinding force components Fn and Ft as well as the roughness parameters Ra and Rz were obtained.
PL
Artykuł dotyczy badań procesu szlifowania obwodowego stali 100Cr6 za pomocą ściernic o spoiwie szklanokrystalicznym. Dokładniej dotyczy badań parametrów chropowatości powierzchni i składowych sity szlifowania w odniesieniu do różnych wartości wskaźnika pokrycia przy obciąganiu, posuwu i głębokości szlifowania. Siedem różnych wartości wskaźnika pokrycia przy obciąganiu zostało wykorzystanych do określenia wpływu wskaźnika pokrycia na siłę szlifowania i chropowatość powierzchni. Po określeniu stabilnego zakresu wskaźnika pokrycia przy obciąganiu przeprowadzono kolejne badania z jedenastoma różnymi wartościami posuwu i dwiema wartościami głębokości szlifowania, aby określić ich wpływ na składowe sity szlifowania i parametry chropowatości powierzchni. Obróbka została wykonana przy użyciu szlifierki CNC do płaszczyzn wraz ze ściernicą obwodową i strategią szlifowania przeciwbieżnego. Dodatkowo do pomiarów sity szlifowania zostało wykorzystano oprzyrządowanie NI. Chropowatość powierzchni została oceniona za pomocą dwóch parametrów (Ra, Rz). Pomiary stykowe chropowatości powierzchni przeprowadzono przy użyciu profilometru MarSurf PS 10. Czynna szerokość obciągacza byle mierzona przy utyciu mikroskopu Dino-Lite AM7515MZT, aby zapewnić stale wartości wskaźnika pokrycia przy obciąganiu w trakcie wszystkich wykonywanych badań. W efekcie uzyskano istotny wpływ wskaźnika pokrycia przy obciąganiu, posuwu i głębokości szlifowania na składowe sity szlifowania Fn i F Ft oraz na parametry chropowatości Ra i Fz.
PL
W artykule przedstawiono krótko wybrane proekologiczne metody chłodzenia i smarowania strefy szlifowania (metodę zminimalizowanego smarowania MQL oraz chłodzenie strumieniem schłodzonego sprężonego powietrza). Opisano istotę hybrydowej metody chłodzenia i smarowania strefy szlifowania otworów, integrującej odśrodkowe podawanie aerozolu powietrzno-olejowego (MQL) przy jednoczesnym podawaniu schłodzonego sprężonego powietrza (SSP).
EN
The article presents briefly selected pro-ecological methods of cooling and lubrication of the grinding zone (minimum quantity lubrication and cooling with a stream of cooled compressed air). The essence of the hybrid method of cooling and lubrication of the grinding zone of internal cylindrical grinding process has been described, which integrates the centrifugal supply of air-oil aerosol (MQL) with a simultaneous supply of cooled compressed air. A numerical simulation model has been characterized. It was used to carry out simulation studies on the flow of cooling and lubricating agents in the grinding zone for conditions corresponding to the assumptions of the proposed hybrid method. The final part of the article presents the results of simulation tests and specifies the most favourable conditions for the application of the hybrid method of cooling and lubricating the grinding zone.
19
Content available remote Obróbka spoin spawalniczych – przegląd dostępnych rozwiązań
PL
Obróbka spoiny to wieloetapowy i wymagający proces. Zespawanie ze sobą dwóch kawałków metalu to tylko część pracy profesjonalisty. Łączone elementy i gotowe połączenie powinny być odpowiednio obrobione – dobór produktów i technika będą zależały od tego, z jakim materiałem pracujemy, na jakim efekcie nam zależy i jakich narzędzi używamy.
PL
W artykule przedstawiono wyniki badań dotyczące porównania parametrów struktury geometrycznej powierzchni (SGP) próbek ze stopu magnezu AZ31 po polerowaniu oraz po wytworzeniu na ich powierzchniach różnego typu biokompatybilnych powłok ochronnych. Zakres prezentowanych badań obejmował proces przygotowania próbek do ich cięcia metodą WEDM, polerowania krążkami ściernymi, chemicznego trawienia oraz modyfikację ich powierzchni poprzez wytworzenie biopolimerowych powłok ochronnych metodą chemicznego osadzania z fazy gazowej CVD.
EN
In this paper the results of investigations concerning the comparison of surface geometric structure parameters of samples made of magnesium alloy AZ31 were presented. The samples were polish and coated of various types of biocompatible protective coatings. The scope of presented studies included the process of sample preparation by WEDM cutting, abrasive disc polishing, chemical pickling and modification of their surface by producing biopolymer protective coating by chemical deposition from gas phase (CVD).
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