BUILT-UP EDGE FORMATION IN MACHINING.

The work described aims to predict conditions under which buil-up edge (BUE) will occur when machining any material, given its stress-strain and thermal properties. BUE forms when there is a newgative stress gradient from the tool rake face into the chip, giving a relatively weak plane within the chip where shear becomes concentrated and fracture occurs. Such gradients can occur in machining low-carbon steel and commercial purity aluminum, under machining conditions corresponding to BUE formation. This mechanism can be used for predictions, but it is necessary to be aware of exceptions arising from metallurgical characteristics which may alter stress gradients, e. g. by localized cracking.