An apparatus for heating three-dimensional printing filaments comprising a heating chamber including an insulation lining and spool holders mounted at a base of the heating chamber, a heater fan assembly mounted above the heating chamber, wherein the heater fan assembly comprises a powered fan and heater configured to heat air and circulate the heated air to the heating chamber, and a diverter situated between the heater fan assembly and the heating chamber, wherein the diverter splits and directs the heated air to the heating chamber through a pair of channels. The apparatus further comprising a plurality of exhaust ports at top sidewall portions and bottom sidewall portions of the heating chamber, wherein the plurality of exhaust ports allowing the heated air to escape from the heating chamber, and fitting adapters comprising apertures that allow filament material to be dispensed from the heating chamber.

An apparatus for drying a coated electrode includes a perforated plate nozzle located above a transfer path for the coated electrode. A duct is provided to connect to an area of the perforated plate nozzle that does not face the coated electrode among areas of the perforated plate nozzle. The duct may supply hot air flowing outside opposite ends of the coated electrode to a lower portion of the coated electrode.

A system (27) arranged to dry a filament (5) used in additive manufacture, the system (27) comprising: a first heater (55) arranged to heat air; a tubing section (29) having a wall (31) defining an enclosed passage (33), the passage (33) arranged to convey a filament (5), the tubing section (29) having an air inlet (51) for providing heated air from the first heater (55) into the passage (33); and a second heater (59) arranged around along at least part of the tubing section (29), in order to further heat filament (5) within the passage (33).