An experimental study is performed using both thermocouples and infrar
ed thermovision to monitor timewise temperature variations of the tool
and workpiece in orthogonal cutting. A semi-empirical formula is deri
ved to express the temperature-time history of the tool surface, using
a local element lumped conduction equation with experimental data-fit
ting. Infrared thermovision identifies the location of the maximum too
l temperature slightly inward from the cutting edge. An optical and el
ectronic microscope reveals the formation of micropits, the origin of
flank and rake wear that originates in the region of surrounding the m
aximum tool temperature. It is disclosed that the progression of wears
is accompanied by a consistent increase in the tool temperature which
in turn accelerates the wearing process. Chip geometry is found to af
fect local steady-state temperatures in the cutting tool. For cast iro
n and copper, chip geometry may causes a zig-zag variation in the stea
dy-state temperature with respect to the rate of material removal for
a change in the feed. The study sheds light on the causes of roughness
of surfaces cut with a hard tool and may thus serve as the first step
in the investigation of surface machining; (C) 1997 Elsevier Science
Ltd.