F-theta lens is an important unit for selective laser melting (SLM) manufacture and generally use a single wavelength as the light source. The dual wavelength f-theta lens has not been used in SLM manufacture. In order to improve the SLM formability, we present the design of the f-theta lens satisfied coaxial dual wavelength SLM manu-facture. Linear scanning was achieved by introducing negative distortion, and chromatic aberration correction was achieved by choosing appropriate glass material and the structural optimization. It is composed of three pieces of spheri-cal lenses. In the scan area of 120mm × 120mm, the focal spots for 532nm laser and 1080nm laser are smaller than 30μm and 60μm,respectively. The lateral color of the designed f-theta lens is less than 1μm between the two wave-lengths,which meet the high precision application requirements of dual wavelength selective laser melting.%在选区激光熔化成形设备中，F-theta镜头是其重要的组成单元，一般采用单一波长作为光源。为了改善选区激光熔化成形性能，首次设计了由三片球面透镜组成的用于共轴双波长选区激光熔化成形的f-theta镜头。通过引入负畸变实现线性扫描，并选择合适玻璃材料、结构设计来消除色差。在扫描面积为120mm×120mm范围内，适用激光波长为532nm和1080nm，对这两波长激光的聚焦光斑分别小于30μm和60μm，横向色差分离小于1μm，满足高精度双波长激光同时共轴选区熔化成形的应用需求。
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