We present an adaptive slicing scheme for reducing the manufacturing time for 3D printing systems. Based on a new saliencybased metric, our method optimizes the thicknesses of slicing layers to save printing time and preserve the visual quality of the printing results. We formulate the problem as a constrained 0 optimization and compute the slicing result via a two-step optimization scheme. To further reduce printing time, we develop a saliency-based segmentation scheme to partition an object into subparts and then optimize the slicing of each subpart separately. We validate our method with a large set of 3D shapes ranging from CAD models to scanned objects. Results show that our method saves printing time by 30-40% and generates 3D objects that are visually similar to the ones printed with the finest resolution possible.