DIMENSIONAL PRECISION OF MIM PARTS UNDER PRODUCTION CONDITIONS

Metal injection molding has a compelling capability in terms of part c onfiguration but the dimensional tolerance is usually much wider than in conventional powder metallurgy The tolerance of commercially produc ed metal injection molded parts is considered to be +/-0.3%. This arti cle discusses how the dimensional precision of metal injection molded parts is influenced by factors such as variability in raw materials, u niformity of feedstock, some aspects of molding and debinding, reactio ns occurring during sintering, and variability in sintered density. Co nsideration is also given to the accuracy of measurement of density Th e article draws on direct experience in the production of ready-to-use feedstock and data in the open literature. An attempt is made to deve lop a model to estimate analytically the influence of important variab les. A better understanding of the factors considered will enable part s producers using this technology to achieve better dimensional precis ion.