5 - Large-chip Metal Removal

Abstract

This chapter discusses metal chip formation and its cutting parameters. All the large-chip processes use cutting tools of defined geometry that are applied in a controlled manner to remove metal at a predetermined rate. The shaping group of machine tools produces chips by a relative linear motion between the cutting tool and the work. This group includes shaping machines, planing machines, and slotting machines, all of which are used mainly for tool manufacture or maintenance work and have little application in modern production. They operate on a reciprocating principle, cutting on the forward stroke, and idling on the return stroke. Increased metal-removal rates, made possible by the development of new cutting materials, have forced machine-tool manufacturers to design new machines capable of large ranges of spindle speeds and feeds. This has necessitated more powerful motors and structures having high rigidity to resist the increased cutting forces and to reduce the likelihood of self-induced vibrations, giving rise to chatter. With increased rates of metal removal, the problem of swarf disposal has become more acute.