Charged particle beam steering arrangement

A method of forming a product using additive layer manufacture is provided. The method comprises forming the product as a series of layers, each layer being formed by fusing powder deposited as a powder bed by scanning the powder bed using a charged particle beam to form a desired layer shape. For each layer, the powder is fused by melting successive areas of the powder bed by scanning the charged particle beam using a combination of a relatively long-range deflector and a relatively short-range deflector, wherein the relatively long-range deflector deflects the charged particle beam over a larger deflection angle than the short-range deflector. Also provided are a corresponding charged particle optical assembly, and an additive layer manufacturing apparatus.