Studying curve interpolator for CNC system

Abstract EN

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.