The existing high-efficiency machining range proposed by Gilbert although widely used has its disadvantages. It does not take into account factors such as the power capacity of the machine tool, the surface finish of the product, tool geometry, the maximum allowable forces and wear. In addition it recommends a machining range instead of a discrete machining point and the production cost is independent of the production time. This paper discusses the use of design of experiments and optimization techniques to account for these factors. The results can be used in computerized machinability data bank systems, an important part of computer integrated manufacturing for automatically selecting the optimal cutting conditions. Two worked examples based on the turning process are used to illustrate the approach. The graphical results show that the optimal cutting speeds obtained by this method fall in the high efficiency zone.