SPC is discussed with a view to indicating its implications not only to manufacturing and quality but to research and product development as well.
In the manufacturing/quality area, the efforts and methods attending full scale implementation of SPC are briefly reviewed with special reference to the differences inherent in powder making versus manufacturing of parts. SPC charting techniques suitable for powder making are described and discussed.
In the product development area, it is shown how SPC influenced a major research program. The objective of the program was to improve premixed products with a view to reducing variability in parts manufacturing.
ANOVA studies of production mixes generally showed that the main sources of premix variability were mix to mix differences and within mix differences arising from demixing subsequent to premix manufacture. It was recognized that SPC is especially applicable to dealing with the first of these and subsequent efforts to implement it to premixes are described. In the case of demixing, the development of a new premixing process is reported in which the alloy admix ingredients are bonded to the iron.
The general findings of extensive studies which show the benefits of the new process in terms of reduced variability in parts manufacturing are reviewed and the results of a study of an FC-0208 premix are presented as an example. SPC theory and concepts are used to indicate the significance of the results and their potential applicability to the production of parts.