Examination of average surface roughness in waterjet cutting

Waterjet cutting is a non-conventional cutting technology. Important criteria of the cut surface are geometric accuracy and surface roughness. The aim of this paper is to provide predictive models to estimate average surface roughness (Ra), taking into account significant effects. Full factorial design of experiments were used in the waterjet cutting tests. The input parameters were plate thickness (mm), grain mass (g/min), and feed rate (mm/min). The quality of the waterjet cut surface depends on the thickness of the cut plate to a great extent (due to the bending of the waterjet or the pressure decrease, etc.), therefore surface roughness was measured in three places along the thickness of the plate and so three predictive models were constructed.