Development of Algorithms to Represent Intermediate Layers for Machining Sculptured Surfaces

Abstract

The objective aim of this research is to develop an algorithm for design and manufacture sculptured surfaces that are common in a wide variety of products such as dies, automobile, and aircrafts components. In the design stage Bezier technique has been used to represent the desire surface. In rough-machining stage, the number of intermediate layers depend on the geometry of the desired surface and on the maximum allowable depth of cut, an algorithm has been proposed to represent these layers, whereas another efficient algorithm has been proposed to represent the semifinished layer depends on the tangents and normal vectors along all the points of the desired surface to create the offset surface. The desired surface generated points using Bezier technique are used as cutter location points for the finish machining tool path. Flat end mill (φ 12mm) has been used for the intermediate stages machining (roughing), while (φ 12mm) ball end mill have been used for both semi-finish and finish machining. The developed algorithm have been tested by several designed sculptured surfaces, its proved good flexibility and efficiently in all of its stages, the results have been implemented for machining one of these surfaces [fifteen intermediate layers, semi-finished layer, and finished] using 3-axis vertical CNC machine. The proposed rough machining algorithm reduces the machining time as compared with contour tool path by 15% for case study two and reduces the NC file size 52% for case study three.

Keywords

• sculptured surfaces
• offset surfaces
• bezier techniques
• intermediate layers
• rough machining
• semi finishing and finishing