Orthogonal cutting of polyurethane foam

This study describes orthogonal cutting experiments performed on rigid polyurethane foams of various densities and cell sizes, to investigate chip formation and surface finish. An optical arrangement was used to visually record the cutting process, while horizontal and vertical cutting forces were measured. A total of 239 measurements were performed with tool rake angles of 23∘, 45∘ and 60∘, and depths of cut in the range of 0.1-3 mm. Continuous and various modes of discontinuous chip formation were identified. While continuous chip formation resulted in smooth surfaces, discontinuous chip formation was often associated with surface damage in the form of cratering, as a result of crack propagation. Results from experiments and modelling suggest that the transition between chip types was dependent on depth of cut, rake angle and cell size. It is concluded, that surface finish is primarily dependent on cell size and depth of cut. Continuous chip formation developed with a depth of cut between one and two times the cell diameter resulted in the lowest surface roughness.