Cryogenically Applied Support and Damping Structures for Chatter Suppression in the Machining of Thin-Walled Components

Abstract

Lightweight components with low wall thickness continue to gain technological and economic importance in aerospace and other industries. Thereby, the low wall thickness and thus high compliance of such workpieces may cause the occurrence of undesired vibrations under the characteristic load of machining operations. The suppression of dynamic effects such as regenerative chatter represents a central requirement for milling operations with regard to the achievable component qualities and process efficiency. Certain approaches base on the application of support structures or damping elements, which are attached to the workpiece. After processing the thin-walled components, however, the added structures have to be removed in elaborate processes. In this paper, a new approach is presented which is focusing on an optimised process stabilisation method using cryogenic solidified coolant. By injecting coolant emulsion into the CO2 snow jet and applying it specifically to thin-walled workpieces, stiffening support structures were generated and damping elements attached. The ice layer melts off after machining and returns into the lubricant circuit with no need for conditioning or additional filtering. Modal tests and machining experiments demonstrated the applicability of the presented approach and a significant decrease of the dynamic compliance and deflection of the workpiece during milling operations.