Addressing Surface Error Problems Found when Using Multiple Axis Milling for the Manufacture of Turbine Impellers

This paper addresses the phenomenon of circular dots, which often occur on the component surface as a result of 5-axis machining. These dots occur typically at the interface of two or more patches owing to the cutter fouling adjoining surfaces whilst machining is being undertaken on a particular patch. The action described above forms a half-dot in the adjoining surface. This is made into a full dot, when, during the machin-ing of the second surface, the first surface is fouled. This paper is concerned with an industrial case study, namely the machining of a hydraulic transmission turbine impeller blade. The work does not eradicate the dot problem; however, it reduces the occurrence. To achieve a component completely free from the dot problem it was necessary to amend the milling strategy to minimise the motion of the A and B axes. RID=" ID=" Correspondence and offprint requests to: Professor D. K. Harrison, Department of Engineering, Caledonian University, City Campus, Cowcaddens Road, Glasgow, G4 0BA, UK. E-mail: dha2@gcal.ac.uk