Scanner - for quasi-simultaneous process
The scanner optics is a combination of optics and motion system.
Two mirrors in the scanner head can be turned quickly, so that a fast deflection of the laser beam in x- and y-direction occurs. The deflection units are so-called galvanometers, which tilt depending on the electrical current - accordingly, the term galvo scanner is sometimes used.
Since only little mass has to be moved with the mirrors, speeds of several meters per second can be achieved. A welding contour can thus be traced several times per second and a quasi-simultaneous process is possible.
The large lens below the scanner head determines the size of the working field. In addition, this so-called f-theta lens also ensures that the focus lies in one flat plane and that the rotation speed of the mirrors is proportionally translated into a translation speed.
With f-theta lenses covering a larger working field, the working distance and also the spot size of the laser increase:
|Working field||Working distance||Spot diameter|
|100 x 100 mm||~ 190 mm||~ 0.75 mm|
|240 x 240 mm||~ 490 mm||~ 2.0 mm|
|350 x 350 mm||~ 550 mm||~ 3.0 mm|