Composite Framework Design Method for Large 5-axis Machining Center Based on Finite Element Analysis

Abstract

The subject of this study is to find a best solution to design and manufacture a composite framework for large 5-axis machining center to meet the large dimensions in x, y and z working space, high accuracy for position of machine tool, lightweight design for good dynamic drive performance and cost effective design. A series of parameter studies and finite element analyses were carried out for this purpose. The goal of optimization design is to minimize the displacements in the milling head while a lightweight design, a reliable fabrication processes and a low material cost. A two-step approach was presented to find out the optimum structure of composite framework using finite element analysis method for a low-stiffness-case and a high-stiffness-case to analyze the maximum deformation of milling head under operational loads, including the gravity and maximum acceleration in each axis for starting and stopping. The results show that, after optimization design for composite framework, the deformations in the milling head were below 0.21 mm in high-stiffness-case and the stress inside the laminate was much lower than allowable material limits, it means that the optimal design of composite framework is feasible and successful. The prototype of 40m×6m×4m large 5-axis machining center was also manufactured and the actual verification results indicate that the composite framework can fully satisfy the design requirements of large 5-axis machining center based on the approach proposed by this work, which can provide a technical guidance for design of large structure to improve its precision.