33 KB483 KB29 KB199920252008Dašić, PredragNatsis, AthanassiosPetropoulos, G.številka:2letnik:549 stranistr. 122-130ISSN:0039-2480COBISSID:10499867URN:URN:NBN:SI:doc-8HSJ23EVenAssociation of Mechanical Engineers and Technicians of Slovenia et al.Zveza strojnih inženirjev in tehnikov Slovenije et al.Strojniški vestnikkmetijski strojiobdelovalni sistemiobrabarezalna orodjazanesljivostModels of reliability for cutting tools| examples in manufacturing and agricultural engineering|Reliability of machining systems depends to a great extent on the reliability of cutting tool performance with the latter being the weak link due to wear. Soil processing systems have many in common with machining systems and a major problem related to use of tillage equipment is ploughshare wear, as it markedly affects tillage quality and agricultural production economy. In the present study a machining and a soil processing example will be given for the determination and modelling of the reliability function R(T)Č for turning of 20CrMo5 steel alloy using Cubic Boron Nitride (CBN) and mixed ceramic cutting tools, and in a tillage operation using a straight toothed harrow. In the machining case, through comparative analysis of theoretical distribution models, which fit closer the experimental data, the Gaussian model is selected to represent the reliability function for both tool materials considered. In the tillage example, by carrying out an optimization procedure based upon the reliability function R(T) of the tillage system, a particular tool tooth geometry was found that establishes the maximum tooth working time possible for a reliable performanceZanesljivost obdelovalnih sistemov je v veliki meri odvisna od zanesljivosti značilk rezalnih orodij kot najšibkejših členov zaradi njihove obrabe. Sistemi za obdelavo zemlje imajo precej skupnega z sistemi za obdelavo kovin - pomemben problem, ki se nanaša na uporabo obdelovalne opreme je obraba lemeža,ki značilno vpliva na kakovost obdelave zemlje in gospodarnost agrotehnične proizvodnosti. V prispevku sta za določanje in modeliranje zanesljivosti R(T) podana primera obdelave kovin in obdelave zemlje: struženje legiranega jekla 20CrMo5 z orodji iz kubičnega borovega nitrida (CBN)in mešane rezalne keramike ter obdelava zemlje z uporabo preprosto nazobčane brane. V primeru obdelave kovin, skozi primerjalno analizo teoretičnih modelov porazdelitve, ki se dobro prilegajo eksperimentalnim podatkom, je tehtno izbran Gausov model za ponazoritev funkcije zanesljivosti obeh rezalnih materialov. V primeru obdelave zemlje je, z izvedenim postopkom optimizacije, ki temelji na zanesljivosti R(T) sistema za obdelavo, dobljena natančna oblika zoba orodja, ki omogoča najdaljši čas delovanja zoba zaradi zanesljive značilkeTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaUniverza v Ljubljani, Fakulteta za strojništvo