Nozzle

A nozzle 100 includes a body 101, a tip 106 insert secured within the body and a flow path 109 described by the body and insert, the flow path includes a filament passageway with an inlet 112 at an upstream body, for receiving a solid or semi-solid filament of build material and narrowing toward an outlet 193 through which molten build material exits the nozzle and is deposited on a build bed in use, and one or more heat transfer elements 10 projecting into the flow path upstream of the outlet, wherein the tip insert is press-fit into a downstream end of the nozzle body and describes an outlet portion including the narrowing and the outlet. The heat transfer insert maybe captivated between the tip insert and a shoulder of the body, and may divide the flow path, describing a meandering or helical portion 80, 83 of the flow path. Each heat transfer element comprises a plurality of fins (62, figure 16) spaced evenly about the periphery of the flow path. A liquefier assembly may comprise a heater and a nozzle and an additive manufacturing system may comprise a nozzle or a liquefier assembly.