THE EFFECT OF OIL POCKET ARRAYS ON FRICTION COEFFICIENT

Tribologia ◽  
2017 ◽  
pp. 97-105 ◽  
Author(s):  
Sławomir WOŚ ◽  
Waldemar KOSZELA ◽  
Paweł PAWLUS
Keyword(s):  
Surface Texturing ◽  
Area Ratio ◽  
Contact Conditions ◽  
Disc Surface ◽  
Abrasive Jet Machining ◽  
Random Arrangement ◽  
Before And After ◽  
Pin On Disc ◽  
Oil Pockets ◽  
Input Variables

Experiments were carried out using pin-on-disc tester in conformal lubricated contact conditions for different normal loads. Surface texturing was done using abrasive jet machining with the application of laser cut mask. In order to eliminate the effect of different input variables in all the experiments, pit-area ratio and sizes of oil pockets were very similar. Five types of oil pocket arrays were tested: radial, concentric, spiral, of a square arrangement, and of a random arrangement for 5% and 17% of pit-area ratio. Different dimple diameters caused various oil pocket densities. The experiments were also made for untextured polished discs. During tests, the friction force was monitored as a function of time. Before and after tests, disc surface topography was measured using a white light interferometer Talysurf CCI Lite. The beneficial effect of surface texturing was obtained for spiral arrays of dimples on disc surface. The presence of a radial array of oil pockets resulted in the worst tribological properties of tribological assemblies containing textured discs.

Effect of triangular oil pockets on friction reduction

2021 ◽  
pp. 135065012110446
Author(s):  
Slawomir Wos ◽  
Waldemar Koszela ◽  
Andrzej Dzierwa ◽  
Pawel Pawlus
Keyword(s):  
Coefficient Of Friction ◽  
Normal Load ◽  
Area Ratio ◽  
Apex Angle ◽  
Friction Reduction ◽  
Textured Surfaces ◽  
Disc Surface ◽  
Pin On Disc ◽  
Oil Pockets ◽  
Spiral Array

The effect of the apex angle of triangular oil pockets created on a disc surface on friction was studied. Experiments were carried out using an Optimol SRV5 tribotester equipped with a pin-on-disc module under unidirectional lubricated sliding. Both the sample and counter sample was made of steel of 45 Hardness Rockwell C (HRC) hardness. Only 1 ml of oil was put to the inlet side of the contact area at the beginning of each test. All textured surfaces had the same pit-area ratio and an average depth of dimples. Oil pockets were positioned in the spiral array. It was found that the effect of the apex angle of triangular dimples on friction reduction was important. When the normal load was lower, the smallest coefficient of friction was achieved for the sliding pair with a disc apex angle of 60°. Under a larger normal load, a higher apex angle corresponded to a higher coefficient of friction.

scholarly journals The Effect of Surface Texturing on Dry Gross Fretting

Lubricants ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 92 ◽  
Author(s):  
Agnieszka Lenart ◽  
Pawel Pawlus ◽  
Slawomir Wos ◽  
Andrzej Dzierwa
Keyword(s):  
Friction And Wear ◽  
Surface Texturing ◽  
Tribological Performance ◽  
Disc Surface ◽  
Abrasive Jet Machining ◽  
Wear And Friction ◽  
Steel Disc ◽  
Disc Configuration ◽  
Effect Of Surface ◽  
Ball On Disc

The effect of steel disc surface texturing on dry gross fretting in a ball-on-disc configuration was studied. Dimples were created with abrasive jet machining. The tribological performance of sliding pairs, steel–steel and steel–ceramics, was experimentally studied. The character of surface texturing effect was related to the dominant wear type. During steel–steel contact, the presence of dimples on disc surfaces could lead to increases in wear and friction. However, the escape of wear debris into dimples could result in reductions of friction and wear in the steel–ceramics configuration.

Modeling of Surface Topography for Reduced Friction

2008 ◽  
Author(s):  
Marko Sedlacˇek ◽  
Bojan Podgornik ◽  
Jozˇe Vizˇintin
Keyword(s):  
Surface Roughness ◽  
Surface Topography ◽  
Surface Texturing ◽  
Test Results ◽  
Textured Surfaces ◽  
Roughness Parameters ◽  
Contact Conditions ◽  
Surface Roughness Parameters ◽  
Pin On Disc ◽  
Texture Size

The aim of the present research was to investigate surface topography in terms of different surface roughness parameters and to correlate surface topography change to friction of contact surfaces. For this purpose, different 100Cr6 plate samples with different surface topography were prepared. Using different grades and combinations of grinding and polishing samples with similar Ra values, but different Rku and Rsk values were obtained. To evaluate influence of roughness parameters on friction and wear, dry and lubricated pin-on-disc tests were carried out under different contact conditions. Test results indicate that high Rku and negative Rsk values lead to decrease in friction. To investigate the effect of surface texturing on surface roughness parameters, real roughness profiles were virtually altered to achieve virtually textured surfaces. Using NIST SMATS softgauge for calculation of surface roughness parameters, virtually altered roughness profiles were investigated in terms of texture size, shape and spacing, and their influence on surface roughness parameters, especially on skewness and kurtosis. Lower diameter, higher spacing and wedge-shaped dimples reflect in higher Rku and more negative Rsk parameters.

Influence of Steel Surface Preparation Method on Topography and Tribological Behaviour in Dry Sliding Conditions

2016 ◽  
Vol 674 ◽  
pp. 265-270 ◽  
Author(s):  
Andrzej Dzierwa
Keyword(s):  
Wear Debris ◽  
Steel Surface ◽  
Preparation Method ◽  
Tribological Behavior ◽  
Surface Preparation ◽  
Tribological Behaviour ◽  
Contact Conditions ◽  
Disc Surface ◽  
Pin On Disc ◽  
Steel Disc

Tribological tests were conducted using a pin-on-disc tester. In the experiment, a steel disc of hardness 40 HRC was put in contact with a steel ball of hardness 62 HRC. Disc samples were prepared in order to obtain very similar values of the Sa parameter, smaller than 0.5 μm. Different methods of preparing smooth surfaces were used. Dry tests using similar contact conditions were carried out. During tests, the friction force was monitored as a function of time. Wear of discs and balls was measured after the test using white light interferometer. In order to decrease variation of the experimental results, during tests the wear debris was continuously removed from the disc surface. It was shown that type of treatment play a role on tribological behavior of sliding pairs.

THE EFFECTS OF SURFACE ROUGHNESS ON FRICTION REDUCTION AS THE RESULT OF SURFACE TEXTURING BY ABRASIVE JET MACHINING

Tribologia ◽  
2016 ◽  
Vol 267 (3) ◽  
pp. 195-204
Author(s):  
Sławomir WOŚ ◽  
Waldemar KOSZELA ◽  
Paweł PAWLUS
Keyword(s):  
Surface Roughness ◽  
Friction Force ◽  
Surface Texturing ◽  
Frictional Resistance ◽  
Friction Reduction ◽  
Textured Surfaces ◽  
Sliding Surfaces ◽  
Abrasive Jet Machining ◽  
Oil Pockets

Various machining methods are currently used to obtain the best co-action of sliding surfaces. Application of two-process surfaces led to a decrease of frictional resistance. Textured surfaces after abrasive jest machining are practical examples of two-process topographies. The results of the application of textured discs with the same array of oil pockets of similar sizes, but with different roughness in areas free of dimples, are presented in this paper. It was determined that after this type of machining, the effect of the friction force decrease was caused by surface texturing.

scholarly journals Friction Reduction in Unidirectional Lubricated Sliding Due to Disc Surface Texturing

Coatings ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 221 ◽  
Author(s):  
Slawomir Wos ◽  
Waldemar Koszela ◽  
Andrzej Dzierwa ◽  
Pawel Pawlus
Keyword(s):  
High Performance ◽  
Surface Engineering ◽  
Combustion Engine ◽  
Surface Texturing ◽  
Friction Reduction ◽  
Spiral Groove ◽  
Disc Surface ◽  
Pin On Disc ◽  
42Crmo4 Steel ◽  
Better Than

Surface texturing is an option of surface engineering resulting in reduction of friction due to the creation of isolated dimples or grooves on sliding surfaces. The purpose of this work is to find the effect of the groove bottom profiles on the reduction of the friction force. Investigations were conducted using an Optimol SRV5 tribotester equipped with a pin-on-disc module. A disc made of 42CrMo4 steel, with a 100 mm diameter acted as a sample. A counter-sample was made of the same material, however, its diameter was 20 mm. The sliding conditions were selected to be similar to those of a sliding crankpin bearing pad operating in a high-performance internal combustion engine. Surface texturing was found to be beneficial for a reduction in the friction coefficient up to 55% in comparison to the untextured disc. Tribological performances of discs with spiral groove patterns were better than those with a radial layout. In most cases the convergent profile of the groove bottom was superior to the dam shape.

Effect of Carbon Pre-Treatment on Pd Dispersion in Synthesis of Pd/C Catalyst

2014 ◽  
Vol 804 ◽  
pp. 149-152 ◽  
Author(s):  
Ji Sun Kim ◽  
Jae Ho Baek ◽  
Myung Hwan Kim ◽  
Seong Soo Hong ◽  
Man Sig Lee
Keyword(s):  
Surface Area ◽  
Nitrogen Adsorption ◽  
Area Ratio ◽  
High Dispersion ◽  
Co Chemisorption ◽  
Pd Dispersion ◽  
Before And After ◽  
Pre Treatment ◽  
Treated Carbon ◽  
Adsorption Desorption

In this study, we confirmed effect of carbon pre-treatment on Pd dispersion in synthesis of Pd/C catalyst. Physical characteristics on the surface of before and after pre-treated carbon were analyzed by nitrogen adsorption-desorption analysis. The dispersion and size of Pd particles were analyzed by XRD, FE-TEM and CO-chemisorption. After pre-treatment, surface area of carbon were decreased. And mesopore area ratio were increased with decreasing micropore area ratio. In the case of pre-treated carbon, we confirmed high dispersion of Pd particles.

Friction Characteristics with Pin-on-Disc Friction Test on Microstructured Surface Using Whirling Electrical Discharge Texturing

2014 ◽  
Vol 1017 ◽  
pp. 417-422
Author(s):  
Vitchuda Lertphokanont ◽  
Takayuki Sato ◽  
Masahiro Oi ◽  
Minoru Ota ◽  
Keishi Yamaguchi ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Electrical Discharge ◽  
Area Ratio ◽  
Mixed Lubrication ◽  
Optimal Conditions ◽  
Friction Test ◽  
Crater Diameter ◽  
Microstructured Surface ◽  
Pin On Disc ◽  
Lubrication Condition

A microstructured surface was created on a steel surface by whirling electrical discharge texturing (WEDT) since it was considered that the microstructures could act as lubricant reservoirs to assist the formation of a lubricating film, resulting in reduced friction. In this study, friction tests under engine oil were carried out over a range of loads and sliding speeds. In addition, the surface characteristics of the microstructured surface were also investigated to optimize the friction characteristics of the textured surface through pin-on-disc friction tests. It was found that under the mixed lubrication condition near the boundary condition, textured surfaces with texture-area ratio of approximately 6% and a mean crater diameter of 35 μm were considered as the optimal conditions for reducing the friction coefficient. However, a texture-area ratio of approximately 4% and a mean crater diameter of 35 μm were considered as the optimal conditions for reducing the friction coefficient under the mixed lubrication condition near the elastohydrodynamic lubrication condition. It was considered that when the normal load decreased, the lubrication region changed from the mixed lubrication condition to the hydrodynamic lubrication condition, which meant that the actual contact surface area decreased. The decrease in the actual contact surface area with decreasing texture-area ratio led to a reduction in the friction coefficient. Finally, it was clarified that the friction coefficient was reduced under the optimized conditions of the microstructured surface through a pin-on-disc friction test.

scholarly journals Effect of Temperature on the Tribological Properties of Selected Thermoplastic Materials Cooperating with Aluminium Alloy

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7318
Author(s):  
Anita Ptak ◽  
Paula Taciak ◽  
Wojciech Wieleba
Keyword(s):  
Aluminium Alloy ◽  
Contact Pressure ◽  
Tribological Properties ◽  
Polymer Materials ◽  
Effect Of Temperature ◽  
Test Results ◽  
Friction Process ◽  
Before And After ◽  
Pin On Disc ◽  
Two Parameters

This article concerns the tribological properties of three selected polymer materials: polyamide PA6, polyethylene PE-HD and polyetheretherketone composite PEEK/BG during sliding against aluminium alloy EN AW-2017A in the presence of hydraulic oil HLP 68. The tests were carried out under contact pressure p of 3.5–11 MPa at ambient temperature T ranging from −20 °C to +20 °C. The dependence of kinetic friction coefficient μk on the two parameters was determined through tribological tests carried out using a pin-on-disc tribometer. A five-level central composite rotatable design (CCRD) was adopted for the experiment. All the test results were statistically analysed. The microhardness of the surface of the polymeric material was measured before and after the friction process. The surface was also examined under SEM. Temperature and contact pressure have been found to have a significant effect on the tribological properties of the tested sliding pairs. Relative to the applied friction conditions, the surfaces after friction showed rather heavy signs of wear.

EVALUATION ON THE TRIBOLOGICAL PROPERTIES OF DOUBLE FRACTIONATED PALM OLEIN AT DIFFERENT LOADS USING PIN-ON-DISC MACHINE

2015 ◽  
Vol 75 (11) ◽  
Author(s):  
N. Nuraliza ◽  
S. Syahrullail ◽  
M.N. Musa
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Tribological Properties ◽  
Palm Olein ◽  
Pure Aluminum ◽  
Engine Oil ◽  
Lubricating Oil ◽  
Hydraulic Oil ◽  
Before And After ◽  
Pin On Disc

The use of vegetable oil-based lubricant as a lubricant in various applications has increased and it is eyed by the industry due to its superior tribological properties, besides possessing the potential to replace petroleum-based lubricants. Palm olein is one of alternative lubricants that could be suitable and attractive as a lubricant to be studied due to its advantages and large production in the country. Thus, in this study, the behavior of palm olein characteristics was investigated by using pin-on-disc experiment, in which a hemispherical pin was loaded against the rotating grooved disc. The experiments via sliding were performed with pin-on-disc tester using pure aluminum as the material for hemispherical pin and SKD11 for disc. The test was implemented by dropping continuous flow of palm olein as lubricating oil on sliding surface at different loads applied, which were 10N, 50N, and 100N. The wear rate of the pin and the friction coefficient were also investigated. Moreover, the surface roughness before and after the experiment was analyzed as well. All the results obtained were compared to hydraulic oil and engine oil-SAE 40. From the analysis, the friction coefficient acquired from lubricated with palm olein was the lowest for both conditions. The wear rate obtained for the three lubricants increased from 10N to 100N load for palm oil, but decreased for hydraulic and engine oil-SAE 40. Meanwhile, the wear rate obtained for lubrication with hydraulic oil showed the lowest value compared to Engine oil-SAE 40 and double fractionated palm olein. 

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