Filament drying system

A system arranged to dry a filament used in additive manufacture, the system comprising:

• a first heater arranged to heat air;
• a tubing section having a wall defining an enclosed passage, the passage arranged to convey a filament, the tubing section having an air inlet for providing heated air from the first heater into the passage;
• a second heater arranged along at least part of the tubing section, in order to further heat filament within the passage;
• a drying control module arranged to control the first heater and second heater to control the amount of water removed from the filament;
• a first temperature sensor arranged to measure an air temperature at an output of the first heater;
• and
• a second temperature sensor arranged to measure an air temperature within the passage;
• wherein the drying control module controls the first heater and the second heater based on the air temperatures measured by the first and second temperature sensors, to control the amount of water removed from the filament.

An additive manufacturing machine comprising:

• a filament store;
• a deposition head including a liquefier for liquefying filament;
• a filament guide for feeding filament from the filament store to the liquefier;
• and
• a system for drying the filament, the system comprising:
• a first heater arranged to heat air;
• a tubing section having a wall defining an enclosed passage, the passage arranged to convey filament from the filament store, the tubing section having an air inlet for providing heated air from the first heater into the passage and forming at least part of the filament guide;
• and
• a second heater arranged along at least part of the tubing section, in order to further heat the filament within the passage;
• wherein the tubing section comprises:
• a filament inlet for receiving the filament to be dried;
• and a filament outlet for providing dried filament, wherein the filament inlet and filament outlet are sealable around the filament such that the passage forms a sealed space, wherein the filament inlet and/or the filament outlet comprise:
• an opening into the passage;
• and a resiliently deformable sealing member closing the opening, the sealing member having an aperture to receive the filament, the edge of the aperture arranged to engage the filament to form a seal.

An additive manufacturing machine comprising:

• a filament store;
• a deposition head including a liquefier for liquefying filament;
• a filament guide for feeding filament from the filament store to the liquefier;
• and
• a system for drying the filament, the system comprising:
• a first heater arranged to heat air;
• a tubing section having a wall defining an enclosed passage, the passage arranged to convey a filament, the tubing section having an air inlet for providing heated air from the first heater into the passage and forming at least part of the filament guide;
• and
• a second heater arranged along at least part of the tubing section, in order to further heat filament within the passage,
• wherein the system further comprises a drying control module arranged to control the first heater and second heater to control the amount of water removed from the filament;
• a first temperature sensor arranged to measure an air temperature at an output of the first heater;
• and a second temperature sensor arrange to measure an air temperature within the passage, wherein the drying control module controls the first heater and the second heater based on the air temperatures measured by the first and second temperature sensors, to control the amount of water removed from the filament.