The authors in DMRL are engaged for last three decades in development and production of a repertoire of tungsten heavy alloy products mainly for defence applications where stringent quality control is imperative. An exhaustive knowledge-base has been built over the years with inputs from literature and in-house use R&D. This knowledge-base generally ensures continuous and smooth production of quality products. But, there was a case where this knowledge-base of sintering had been proved to be incapable of ascertaining and solving certain production problem. This particular problem was analysed and solved by Ishikawa technique. Based on the experience, the authors advocate that the knowledge of different statistical and problem solving tools is essential in the field of powder metallurgy.