Patent US 5,907,488

A method of evaluating quantitatively in a design stage degrees of difficulty of works and processings to be performed on an article or parts at various stage of life thereof such as manufacturing, sale, use, maintenance/inspection/repair, recovery, dismantling, disassembling, recycling for resources, nontoxication and scrapping. Part elimination scores E.sub.i representing degrees of difficulty of the works and processings to be performed on the parts are regarded to be a function of indexes indicating the degrees of difficulty of the works and the processings for the parts and expressed by E.sub.i =f(G.sub.i), while an article evaluation score E representing the degrees of difficulty of the work and the processing for the article is regarded to be a function of a mean value of the part evaluation scores E.sub.i or an index G (=.SIGMA.G.sub.i) indicating the degrees of difficulty of the work and the processing for the article and expressed by E=f(G)=f(.SIGMA.G.sub.i). Further, work and processing costs for the article under evaluation or parts are estimated on the basis of work and processing costs required really for an article or parts bearing similarity to the article under evaluation or parts thereof.