Engineering and Technology Journal

Abstract

This thesis focuses on developing algorithm to calculate best length line
segments in (u) and (w) directions. By of tool paths for free form surfaces based
on the required accuracy of the manufactured part, which is represented by
mathematical curves and surfaces. Bezier method was used to apply the proposed
algorithms. The proposed algorithms consist of two parts; the first part is to
calculate the better length line segment in (u) direction between cutter contact
points (CC), the second part is to calculate the better line segment in (w) direction
depending on the type of surface, cutter radius, tolerance and height scallop being
given. The algorithms are applied in production field such as design of extrusion
dies using three types of curve interpolation such as approximation cubic Bezier,
interpolator Bezier and compound-CRHS profile die. In this paper, the
manufactured parts are machined using a 3-axis CNC milling machine. The
machining operations are simulated using SURFCAM software depending on the
different interpolation techniques mentioned. An evaluation test is applied to the
three interpolation methods based on Finite Element Method (FEM) using
ANSYS 9.0 software to expect the strain and force required to extrude billet
through the dies which are designed using the three mentioned interpolation
methods. The G-code programs have been implemented on 5-axis CNC machine
(Okuma VH-40-HS dynamic machine), the sample material is (cibatool) and the
machining process is achieved without a lubricant at the Protoshop Oy in
Helsinki/Finland.