Estimation of Machining Time in Turning

There was an interesting Study by E. Merchant, an advocate and spokesman for the machine tool industry for several years. He observed that materials in a typical metal machining batch factory or job shop spend more time waiting or being moved than in processing. Approx 95% of a part's time is spent either moving or waiting (temporary storage). Only 5% of its time is spent on the machine tool. Of this 5%, less than 30% of the time on the machine (1.5% of the total time of the part) is time during which actual cutting is taking place.

The remaining 70% (3.5% of the total) is needed for loading and unloading, part handling and positioning, tool positioning, gaging, and other elements of non-processing time. These time proportions provide proof of the importance of material handling and storage in a typical factory.