Integrated control of galvo and x-y stage improves laser-scribing accuracy

The new process allows simultaneous control and movement of the galvanometer scanner and the x-y stage.

Galvanometer (galvo) scanners offer high-speed laser scribing, but are inherently limited by their field of view, which is often no more than 100 × 100 mm. Consequently, there is growing interest in combining high-speed laser galvanometer scanners with larger motion platforms to enable flexible laser machining processes.

The galvanometer scanner is typically isolated from the controls for the machine stage, and the two platforms must work together in a stepwise manner. The stage moves the scribing surface to an appropriate position under the galvanometer scanner, and signals that scanning can begin. Once this operation is completed, the process is repeated until the entire design has been scanned. This process—often called “step and scan”—has a number of drawbacks. The start-and-stop nature of the process, as well as the difficulty in controlling two systems founded on different principles, is inefficient. Close examination of laser-scribed lines also reveals breaks or stitching errors at junctions where the scanning has had to be carried out in two separate steps.

A collaboration between Physik Instrumente (PI; Auburn, MA), ACS Motion Control (Migdal HaEmek, Israel), and Scanlab (Munich, Germany) has developed a novel solution called XLSCAN (eXtra Large Scan). The new process combines the operation of the two instruments into an integrated platform, allowing simultaneous control and movement of the galvanometer scanner and the x-y stage. This effectively overlays the small field of view of the scanner with the longer travel of the stage, enabling continuous scanning without stitching errors. Throughput is also increased (up to 41% in some instances) and the zero-following error of the galvanometer scanner delivers what PI calls “the highest accuracy in the market for such a system.” Contact Katy Evans at k.evans@pi.ws.

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