The high potential of using group technology in manufacturing has attracted the interest of both practitioners and researchers.
Group technology is based on clustering parts which have similar features.
Very often it is very hard to quantify successfully data regarding these features. This is because in many real applications features are fuzzy. The paper presents a methodology for quantifying the data that refer to the fuzzy features. The proposed methodology deals with crisp and fuzzy data in a unified manner. Finally, some clustering approaches which process the quantified features are also discussed.