Wyniki wyszukiwania - BazTech

1

Two-stage optimization of oscillatory burnishing parameters

Ogiński L., Płonka S., Zyzak P.

Advances in Manufacturing Science and Technology

|

2014

|

Vol. 38, nr 4

23--38

EN

The paper presents an issue of optimal parameters selection of oscillatory burnishing operation in terms of coverage surface with microgrooves Sr and time of the operation t for the I-st type system of aftermachining marks (not intersecting each other). It has been evaluated a range of rotational speeds of a workpiece np, number of oscillations of burnishing element nosc, and values of feedrate f, for which the coverage surface with microgrooves amounts to Sr = 34 ± 0.5%. Next, it has been performed selection of such association of the above parameters for which oscillatory burnishing time t of a selected surface is the shortest. A system of microgrooves, which was verified in the test bench, has been modeled for optimal parameters of the oscillatory burnishing.

PL

W pracy przedstawiono zagadnienie doboru optymalnych wartości parametrów nagniatania oscylacyjnego z uwzględnieniem kryterium powierzchni pokrycia mikrorowkami Sr oraz w czasie obróbki t dla I. rodzaju układu śladów poobróbkowych (nieprzecinających się). Określono zakres wartości prędkości obrotowej przedmiotu np, liczby oscylacji elementu nagniatającego nosc oraz wartości posuwu f, dla których powierzchnia pokrycia mikrorowkami Sr = 34 ± 0.5%. Dokonano następnie wyboru skojarzenia wartości parametrów, dla których czas nagniatania oscylacyjnego t zadanej powierzchni jest najmniejszy. Dla ustalonych wartości parametrów nagniatania oscylacyjnego opracowano model układu mikrorowków i prowadzono jego weryfikację na stanowisku badawczym.

2

Modeling and simulation of oscillatory shot peening process

Frydel B., Płonka S., Zyzak P.

Advances in Manufacturing Science and Technology

|

2013

|

Vol. 37, nr 4

5--17

EN

The paper discusses issue of selection of oscillatory shot peening parameters in terms of layout of microgrooves and surface coverage by the microgrooves. There are presented results of modeling and simulation of such method of burnishing, aimed at optimization of processing parameters. Computer program developed on the base of calculation algorithms for relevant parameters of the oscillatory shot peening should simulate conditions of real processing, creating possibilities to change of virtual machine tool parameters, comparing intentional effect of the processing with the one obtained in practice. Thanks to this, in a relatively short period of time it is possible to make selection of optimal parameters of the oscillatory shot peening with respect to surface covered by the Sr microgrooves in such type of microgrooves system.

PL

W pracy przedstawiono zagadnienie doboru warunków procesu kulkowania oscylacyjnego z uwzględnieniem kryteriów układu mikrorowków oraz powierzchni pokrycia mikrorowkami. Przedstawiono wyniki modelowania i symulacji tego sposobu nagniatania, w celu optymalizacji parametrów obróbki. Na podstawie algorytmu obliczania odpowiednich korelacji parametrów kulkowania oscylacyjnego opracowano program, który odtwarza warunki rzeczywistej obróbki, poprzez zmiany wartości parametrów wirtualnej obrabiarki. Porównano zamierzony efekt obróbki z uzyskanym w praktyce. Umożliwia to w krótkim czasie dobór optymalnych warunków procesu nagniatania oscylacyjnego, przyjmując jako kryterium rozmiar powierzchni pokrytej mikrorowkami Sr, w tym układ mikrorowków.

3

The influence of the microgrooves on the hydrodynamic pressure distribution and load carrying capacity of the conical slide bearing

Czaban A.

Journal of KONES

|

2012

|

Vol. 19, No. 3

85-91

EN

The aim of this work is to determine the hydrodynamic pressure distribution in oil film and the load carrying capacities of conical slide micro bearings with grooved sleeves. The results for some bearings examples are presented. For the bearings taken into account, the Reynolds equation was solved by the method of Finite Differences. In the calculations, the Reynolds boundary condition was applied. The simulation was performed for the conical slide micro bearings with the groves parallel to the cone generating line. The function of lubrication gap height for the conical slide bearings with sleeves covered with microgrooves was assumed on the basis of existing papers. The results obtained for the analogous bearings without the microgrooves are also shown, therefore the influence of microgrooves on the conical slide micro bearings can be observed. On the basis of the results, one can conclude, that applying microgrooves on the bearing sleeve surface causes the increase of the value of hydrodynamic pressure and longitudinal and transverse components of the load carrying capacity of the bearing. Furthermore, the effect of the microgrooves and their impact is noticeable in graphs of hydrodynamic pressure distribution. The applied method of investigation of the impact of microgrooves on a bearing operation is simpler and less expensive than the experimental studies, however it is necessary to verify that the results obtained with this method are correct and whether in fact applying microgrooves, besides form facilitate lubrication, causes the improvement in bearing operating parameters.

4

Surface topography of operated slide journal micro - bearings used in computer fans

Miszczak A., Czaban A., Labuda W.

Journal of KONES

|

2012

|

Vol. 19, No. 4

457-463

EN

In this paper authors present results of measurements of slide journal bearings surface topography measured with a profilometer and an atomic force microscope (AFM). Surface topography of investigated bearings (i.e. journals and sleeves) was measured using the Hommeltester T8000- R60 profilometer. The results of these measurements give information about micro-grooves dimensions and location. Measurements of surface topography were made for journals and sleeves of slide journal micro-bearings from personal computers fans, with the Atomic Force Microscope NT-206 produced in MTM in Minsk, Republic of Belarus. The results of measurements of surface topography were presented in the form of surface topography maps, threedimensional graphs and some examples of selected cross-sections of investigated surfaces in the form of profile graphs. The values of profile roughness parameters Ra and Rq and the distance between maximum peak height and maximum valley depth are presented as well. The application SurfaceXplorer registered trademark was used for processing and visualization of the data obtained from AFM NT-206, which besides from generating 2D, 3D and profile diagrams, was used to calculate and draw graphs of height distribution. In this research authors used two identical sets of micro-bearings. The investigated bearings are: a) Kama Flow SP0825FDB12H fan with grooved surface of bearing sleeve, b) Xilence Case fan which sleeve surface was without grooves. First set of that micro-bearings functioned for a year at rated RPM continuously (i.e. 24 hours a day). Second set of the same micro-bearings also functioned for a year at rated RPM, but in intermittent mode (i.e. 15 minutes on, 15 minutes off). On the surfaces of studied micro-bearings some microgrooves can be found in form of herringbone, with depth about 1-2..m and width 100-150..m. Received information about microgrooves geometry will help to develop proper theory of hydrodynamic lubrication for micro-bearings with microgrooves and allows determining how the mode of operating affects on the wear of co-operating surfaces.

5

Surface topography of operated slide journal micro - bearings used in HDD

Miszczak A.

Journal of KONES

|

2012

|

Vol. 19, No. 4

449-456

EN

In this paper author present results of measurements of slide journal micro-bearings surface topography measured with an atomic force microscope (AFM). The results of measurements of surface topography were presented in the form of surface topography maps, three-dimensional graphs and some examples of selected cross-sections of investigated surface in the form of profile graphs. Measurements of surface topography were made for journals and sleeves of slide journal micro-bearings from personal computers' hard disc drives, with the Atomic Force Microscope NT-206 produced in MTM in Minsk, Republic of Belarus. In this research author used two identical sets of micro-bearings from 2.5" HDD Samsung HM160HI 5400rpm and 3.5" HDD Seagate Barracuda 7200.10 ST380815AS 7200 rpm hard disc drives. First set of those four microbearings worked for a year at rated RPM continuously (i.e. 24 hours a day). Second set of the same micro-bearings also worked for a year at rated RPM, but in intermittent mode (i.e. 15 minutes on, 15 minutes off). The values of profile roughness parameters Ra and Rq and the distance between maximum peak height and maximum valley depth are presented as well. The application SurfaceXplorer registered trademark was used for processing and visualization of the data obtained from AFM NT-206, which besides from generating 2D, 3D and profile diagrams, was used to calculate and draw graph of height distribution. Surface topography of investigated bearings sleeves was also measured using Hommeltester T8000-R60 profilometer. Those measurements give information about micro-grooves dimensions and location. On the surfaces of studied micro-bearings, some micro-grooves can be found in form of herringbone, with depth about 1.5..m and width 150..m. Received information about micro-grooves geometry will allow developing proper theory of hydrodynamic lubrication for micro-bearings with micro-grooves.

6

Surface topography of non-operated slide journal micro-bearings

Czaban A., Miszczak A.

Journal of KONES

|

2011

|

Vol. 18, No. 2

109-115

EN

In this paper authors present results of measurements of slide journal bearings surface topography measured with an atomic force microscope (AFM). The results of measurements of surface topography were presented in the form of surface topography maps, three-dimensional graphs and some examples of selected cross-sections of investigated surface in the form of profile graphs. Measurements of surface topography were made for journals and sleeves of slide journal micro-bearings from personal computers' hard drives and fans, with the Atomic Force Microscope NT-206 produced in MTM in Minsk, Republic of Belarus. The values of profile roughness parameters Ra and Rq and the distance between maximum peak height and maximum valley depth are presented as well. The application SurfaceXplorerŽ was used for processing and visualization of the data obtained from AFM NT-206, which besides from generating 2D, 3D and profile diagrams, was used to calculate and draw graph of height distribution. Surface pictures of investigated bearings sleeves were made with the optical microscope Zeiss Axiovert 25+. That measurements give information about micro-grooves dimensions and location. On the surfaces of studied micro-bearings some micro-grooves can be found in form of herringbone, with depth about 1.5mi m and width 150/mi m. Received information about micro-grooves geometry will allow to develop proper theory of hydrodynamic lubrication for micro-bearings with micro-grooves. Topography of surfaces of investigated journal micro-bearings will be reconsidered after exploiting them proper amount of time.