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Shaping the Topography of the Active Surface of a Ceramic Grinding Wheel with a Stationary Multi-Point Diamond Dresser

Dębkowski Ryszard, Gołąbczak Marcin

Advances in Science and Technology. Research Journal

2024

Vol. 18, no 2

266--283

The paper presents issues related to shaping the topography of the grinding wheel as a result of the impact of a stationary multipoint diamond dresser. The result of the dressing process with diamond multipoint dressers is influenced by the dressing feed, the effective width of the individual diamonds and the distance between the diamonds measured along the dressing feed direction. The paper presents simulation results the influence of these parameters on the multiplicity of contact between generatrix of the flat grinding wheel type 1 and the dressing diamonds. The results of the simulation showed that, depending on these parameters, areas with no contact with diamonds and areas with different multiplicity of contact may form on the surface of the grinding wheel. This means that the active surface roughness of the grinding wheel may not be uniform. Two indexes were proposed to enable supervision of the dressing process using stationary multi-point dressers. The first index (k1) characterizes the average multiplicity of contact between the diamonds and the grinding wheel along its generatrix, and the second (k2) the possibility of forming a spiral ridge on the grinding wheel surface due to the lack of contact between this part of the grinding wheel and the diamonds. The work analyzes the changes in the indexes values as a function of the dressing feed rate and the active width of diamonds for two basic types of diamond distribution on the working surface of the dresser, i.e. uniform and irregular spacing. The study presented the results of evaluating the topography of the flat aluminum oxide vitrified grinding wheel type 1 subjected to dressing with various values of indices k1 and k2. The assessment was carried out on the basis two-sample Kolmogorov-Smirnov test and statistical analysis of parameters for evaluating the microgeometry of the grinding wheel circumferential profile, i.e. the depth of active cutting edges and the undeformed chips thickness. The analysis confirmed the lack of homogeneity of the surface topography of the grinding wheel formed with a stationary multipoint dresser and the purposefulness of using the k1 and k2 indexes.

Wpływ stopnia wzajemnego przekrycia na zacieranie adhezyjne

Nosal S.

Tribologia

2002

nr 4

1261-1266

W referacie przedstawiono wyniki badań odporności na zacieranie adhezyjne zimne stalowego węzła ślizgowego o różnym stopniu wzajemnego przekrycia. Stopień ten określono jako stosunek powierzchni tarcia nieruchomego elementu skojarzenia ślizgowego do powierzchni tarcia elementu ruchomego. Różne wartości tego stopnia uzyskano szlifując promieniowo rowki na płaskich próbkach wykonanych ze stali 10. Z płaską próbką ślizgowo współpracowała powierzchnia czołowa tulejki, również ze stali 10. Jedna partia próbek płaskich i wszystkie tulejki zostały poddane nawęglaniu i odpuszczaniu do twardości 40š2 HRC. Druga partia próbek płaskich nie była obrabiana cieplnie. Prędkość ślizgania wynosiła 0,024 m/s. Para tarcia była smarowana zanurzeniowe olejem parafinowym. Docieranie prowadzono przez 5 minut pod obciążeniem 400 N, następnie co minutę zwiększano obciążenie aż do wystąpienia zacierania. Stwierdzono, że wraz ze zmniejszaniem stopnia wzajemnego przekrycia od Kwp = l do Kwp = 0,48 nacisk jednostkowy zacierania zwiększył się ok. 2-krotnie, natomiast zmiana obciążenia zacierania zależała od rodzaju próbki. Największe wartości obciążenia zacierania skojarzeń z miękką próbką stwierdzono dla Kwp = 0,8-0,9. Dla skojarzeń z twardą próbką parametr ten nie ulegał istotnym zmianom.

Results of the research on resistance from cold adhesive scuffing of steel sliding pair with different overlap ratios are presented in this paper. Overlap ratio was assumed as sliding pair element's passive (immobile) friction in relation to friction surface of active (mobile) elements. These different ratios had been obtained by grinding in radins the grooves on a flat specimen made of steel 10. This specimen cooperated in sliding with the front surface of sleeve, also made of steel 10. First group of flat specimens and all sleeves were carburized and tempered to hardness 40š2 HRC. Second group of specimens was not thermal processed. Sliding velocity amounted to 0.024 m/s. Sliding pair was dip-feed lubricated with paraffin oil. Trials were carried during 5 minutes under the load of 400N and afterwards load was gradually with increasing by 200N every minute until scuffing. It had been stated that change in overlap ratio from K=1 to K=0.48 resulted in twofold increase in unit pressure at scuffing, while change in scuffing load depended on specimen's type. The highest load value for scuffing in pairs with soft specimen was stated at K=0,8-0,9. For pairs with hard specimen this parameter did not change considerably.