Heat buildup in cutting will speed the erosion mechanisms in tools, and will cause deformations in the workpiece, which may increase scrap rates. Thermal cycling, that is, rapid heating and cooling, is a concern with interrupted cutting. This effect may cause great harm to tools, the machine tool, and the workpiece. Heat generation can also cause cutting fluids to increase their evaporation and breakdown rates, and to actually cause fires with flammable and semi-flammable cutting fluids.
The following are links to other manufacturing heat generation related sites:
Heat in Machining
Steve Batzer at firstname.lastname@example.org