针对薄壁叶片不等宽的结构特征，提出基于光内送粉方式采用变光斑一次扫描而非多道搭接直接成形出不等宽熔覆层的方法，逐层堆积直接制造薄壁叶片。研究了变斑过程中等高度单道及“阶梯型”单道对薄壁件成形质量的影响规律。实验结果表明：在保证送粉量足够的条件下，变光斑过程中通过实时变扫描速度及激光功率，能够直接熔覆出高度相等、宽度逐渐变化的单道熔覆层；基于等高度单道的变斑堆积过程中熔覆层增长高度并不一致，宽高比大的部位生长高度要大于宽高比小的部位的问题，建立了熔覆层提升量、单层生长高度和熔覆层截面曲线阶数的理论模型，提出了“阶梯型”单道变斑直接成形方法，解决了熔覆层高度生长不一致的问题，获得了熔覆层宽度从1 mm 到3 mm 连续变化的薄壁叶片，为光内送粉激光直接成形薄壁变壁厚类零件提供新方法。

With unequal width structure characteristics of thin-walled blades, single track by variable laser spot based on coaxial inside-laser powder feeding rather than multi-track overlapping is adopted, and the thin-walled blade can be fabricated layer by layer directly. The forming quality of thin-walled blades is investigated by variable laser spot based uniform height and stepped single track. The experimental results show that a uniform height cladding layer with different widths can be got by controlling scanning speed and laser power under the condition with sufficient powder mass flow rate. The growth rate of cladding layers isn′t consistent based on uniform height single-trace cladding layer, and the large ratio of width to height position increases quickly. The theoretical model among layer thickness of Z axis, height of single-trace cladding layer and the section curve order of cladding layer is established, and the stepped single track method is put forward to solve the problem of inconsistent growing height. The thin-walled blade with good forming quality can be achieved. This new method can be provided for forming unequal width blade by laser direct forming with coaxial inside-laser powder feeding.