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Design of alterable laser thread length scan system

In the rapid prototyping technology with laser as an energy source, the method of laser spot scan is used usually. The laser beam is focused to a spot on the working plane through a lens. The scanners work in two ways, one is rotating mirror scan, other is guideway scan. Based on the position of the scanners, the rotating mirror scan can work in pre and behind- objective scan respectively. In this paper, a new laser scan method of alterable thread length is proposed, after analyzing the inherent weak points of the laser spot scan. The design principles of beam deformation unit (changing the laser beam into a thread of light) and the altering length unit are introduced.