SCIENCE AND TECHNOLOGY ENGLIAH FOR MECHANICAL ENGINEERING As an example, if there is a big difference between the diameters of the hole and the recess shown in Fig 6.1, the boring of the recess must be accomplished in several passes. In each pass, a layer of material is removed. However, all these passes are part of the recess machining operation element since none of the cutting tool, machined sur face, cutting speed or feed changes There are many elementary handling operations for the operator to accomplish a given operation, an operation element or a pass(for example, loading and unloading the workpiece, changing the tool, starting the machine tool advancing the tool to approach the workpiece, measuring the machined surface, etc. ) Among them, the set-up of the workpiece plays an important roleSCIENCE AND TECHNOLOGY ENGLISH FOR MECHANICAL ENGINEERING As an example, if there is a big difference between the diameters of the hole and the recess shown in Fig.6.1, the boring of the recess must be accomplished in several passes. In each pass, a layer of material is removed. However, all these passes are part of the recess machining operation element, since none of the cutting tool, machined surface, cutting speed, or feed changes. There are many elementary handling operations for the operator to accomplish a given operation, an operation element or a pass (for example, loading and unloading the workpiece, changing the tool, starting the machine tool, advancing the tool to approach the workpiece, measuring the machined surface, etc.). Among them, the set-up of the workpiece plays an important role