Computer aided design and numerically controlled manufacture of a split mould for a composite model ship propeller

摘要

A method is described of converting a standard table of offsets for a propeller design into a numerical description of the blade surface. This numerical surface description can then be used as a computer-aided design tool and also as a basis for producing data to drive a 3-axis numerically controlled (N.C.) machine tool for the manufacture of the blade or blade mould.The report is divided into two main sections. The first section details the definition of the propeller numerical surface using quadratic parametric splines, and the elementary stress analysis and graphical output used in the development of a propeller design. The modified design was based on the Wageningen B4.40 propeller and was to be used for an investigation into ship propeller/rudder interactions. The second section covers the method by which the split female mould was N.C. machined for this modified propeller design.