US Patent 9174388 Draw control for extrusion-based additive manufacturing systems

A method for improving part quality for a printed three-dimensional part, the method comprising moving a print head nozzle along a substantially linear segment of a tool path at a tip height above a previous layer of the three-dimensional part while extruding a flowable material, and producing an extruded road from the extruded flowable material having a road height above the previous layer, where the tip height is greater than the road height due at least in part to draw on the extruded road.