An Evaluation Method of a Machined Shape with Free-form Surfaces Based on the Detection of Positional Vectors and Unit Normal Vectors

This paper proposes an evaluation method of a mechined shape with free-form surfaces and describes the basic way of thinking for the evaluation in which free-form surfaces are classified into a style surface and a function surface according to the application purpose. The evaluation items of a style surface and a function surface are determined as a unit normal vector and a positional vector respectively. The transformation from a designed shape to a machined shape is assumed as a model of a coordinate transformation, and the permitted transformations in the evaluations of a style surface and a function surface are clarified. The evaluation procedure based on the detection of positional vectors and unit normal vectors at sixteen arbitrary points on a patch of a machined surface is described in detail. In addition, the validity of the proposed evaluation method is examined by a computer simulation.