Options
2008
Conference Paper
Titel
Control of advanced alignment systems in high precision micro-machining of complex shapes
Abstract
The work presented in this paper shows how work piece measurement data (i.e. reference data) can be put in relation to the machine coordinate system using an automated active alignment system. A complete automation of the procedure appears very promising for a reliable referencing sub micrometric accuracy. This automation process has been estimated to strongly improve present state of the art because the largest influence on the accuracy derives from the manual or semi-automated referencing routines. Compared to state of the art manual work piece referencing where a typical accuracy of about 10 micrometer is obtained, the referencing accuracy could be increased by a factor 100 by the semi-automated referencing process. A complete automation of the procedure appears very promising for a reliable referencing accuracy below 0.1 micrometer. The essential input raising from this research work increase the possibility of integration into control system of measurement data. Moreover the experiences done, suggest that, with the use of the vision system described, further possible applications can be explored and achieved in the future, like the complex monitoring of work piece. In fact concepts behind the control of the active alignment system (capability of compensating offsets of the pallet and then of the work piece in machine tool) could be extended. The CCD cameras could also be used for the control of the active alignment chuck by permanently measuring the reference mark positions, realizing a closed-loop control during the alignment process and also during machining. This can be done directly retrieving markers positions from CCD cameras and providing them into CNC. In fact a direct communication with the acquisition and data elaboration software of the CCD system can improve the positioning control for instance implementing an iterative process of markers reading.