Requirements. In order to be able to carry out flexibly adjustable, inclined machining even in the confined space of a rotary transfer machine, the engineering department of imoberdorf AG was commissioned with the development of a swivel axis. The core requirements were to quickly position a large mass with high accuracy and dynamics on a three-axis unit. The position of the axis should be able to be held exactly without clamping under changing cutting forces. The structure required for this should be moved with sufficient rigidity and precision, despite the rough ambient conditions of a rotary transfer machine.
Concept. It quickly became apparent that the installation space for a servo-motor adjustment via a conventional ball screw solution was very tight. Various analyses have shown that a hydraulic adjustment can best cover the requirements. A suitable concept was developed with an appropriately rigid non-locating bearing, a glass scale for the dimensional feedback of the position and the integration of an appropriate hydraulic cylinder for the function. The kinematics and the hydraulic system were simulated and analysed together with Bosch before realisation.
Solution. In order to enable simultaneous machining with the remaining geometry axes in a further step, the swivel axis is integrated into the CNC control 840D sl via an S120 hydraulic drive from Siemens. A Bosch control directional control valve is used as an actuator. The feedback of the position via a glass scale from Heidenhain leads to a dynamically controllable positioning in space. The requirements for rigidity and accuracy during the machining process are successfully met under the ambient conditions of the rotary transfer machine. The implemented development is a complete success for imoberdorf AG and opens completely new doors for the company in terms of flexibility with the expansion of the product portfolio.