Shape Accuracy Improvement Obtained by μ-SPIF by Tool Path Compensation

Abstract

In this paper, the focus will be on the micro single-point incremental forming technique (μ-SPIF) consisting of forming thin sheets (less than 1mm) using a hemispherical tool. The formability limits for incremental forming are higher than for conventional plastic deformation processes. The second advantage of this technique is that it does not require specific tools (dieless process). Although the μ-SPIF process increases flexibility and reduces installation costs, it is constrained by many problems related to large decreases in thickness and significant shape defect. The purpose of this communication is to propose a technique for compensating, after the fact, for shape defects related to forming and springback. The proposed technique consists in defining parametric tool paths using B-Splines curves. The trajectory thus applied to the CAD geometry is generated. The forming of a part is then carried out using this initial trajectory. After digitizing the obtained shape, a comparison is made between the obtained geometry and the specified geometry. A compensation algorithm is then applied to generate an optimized trajectory that takes into account forming and springback defects. After applying this new path, the part is then made and the interest of this approach is demonstrated by comparing the specified, obtained and optimized geometries.