Adequate manufacturing cost estimation and uses of optimally designed manufacturing processes are ones of the major criterii for achieving longer financial sustainability of any industry in its business particularly during this worldwide economic crisis period. Unwise manufacturing cost estimation based on un-optimised processes may either overestimate a product cost for market or underestimate different fractions of cost. These can cause either loss of saleability and competitiveness of a product in the market or the concerned company may loose the revenue this or other ways. Adequate and accurate product design as well as proper manufacturing processes design and assigning only required level of dimensional tolerances, surface finish grade, and other quality aspects are the major issues for winning the sales-compatibility of a product. The current research work concentrates on development of an innovative modelling of production cost calculation in metal machining industries based on highly analytical manufacturing processes considering optimised cutting regimes. An example of machining parameter optimisation to reduce the production cost reducing the operation time has been displayed. Implication of optimised machining processes will yield the best possible surface integrity, higher dimensional accuracy within set tolerances. It’s envisaged that the number of defect products will be substantially decreased. Manufacturing industries will be benefited applying this new method of production / manufacturing cost estimation and using results of processes optimisation.