The asynchronous linear hotwire cutting (ALHC) system of expandable polystyrene (EPS) foam is a new rapid prototyping (RP) technology, which uses the asynchronous linear hotwire cutter and EPS foam to fabricate the part. The efficiency and capacity of ALHC system depends significantly on the pre-process of STL model. This paper presents an original algorithm for adaptively decomposing a STL model into a set of variable slices, which can be efficiently fabricated by ALHC system. A large complex model is first partitioned into several smaller and simpler sub-models by using the curvature-based partitioning. Then, these sub-models are sliced into layers with different thickness based on feature facets. Several experimental results demonstrate the reliability and efficiency of the slicing algorithm.