Method and apparatus for forming layers of particles for use in additive manufacturing

An apparatus for forming a particle layer, the apparatus comprising:

• a vessel for receiving a carrier liquid such that, when the carrier liquid is present in the vessel, the carrier liquid defines a gas-liquid interface with an ambient gas;
• an injection assembly configured to inject particles in an injection zone defined at the gas-liquid interface;
• a flow control assembly disposed in the vessel such that, when the carrier liquid is present in the vessel, the flow control assembly is submerged at least partly in the carrier liquid and configured to control a flow of the carrier liquid along the gas-liquid interface, the flow of the carrier liquid carrying the particles downstream along a particle flow path from the injection zone to a layer formation zone where the particles accumulate and gradually form the particle layer on the gas-liquid interface;
• and
• a transfer assembly configured to withdraw the formed particle layer from the layer formation zone
• wherein the flow control assembly is configured to control a flow of an up per portion of the carrier liquid extending from the gas-liquid interface down to an operating depth below the gas-liquid interface,
• wherein the flow control assembly comprises at least one flow control device, each flow control device being located at the operating depth and being operated at an operating speed parallel to the gas-liquid interface, and
• wherein the at least one flow control device comprises at least one belt conveyor.

A method for forming a particle layer, the method comprising the steps of:

• providing an apparatus for forming a particle layer, the apparatus comprising:
• a vessel for receiving a carrier liquid;
• an injection assembly;
• a flow control assembly disposed in the vessel such that, when the carrier liquid is present in the vessel, the flow control assembly is submerged at least partly in the carrier liquid;
• a transfer assembly;
• and
• a movable barrier;
• injecting, using the injection assembly, particles in an injection zone defined at a gas-liquid interface between the carrier liquid received in the vessel and an ambient gas;
• controlling, using the flow control assembly, a flow of the carrier liquid along the gas-liquid interface to carry the particles downstream along a particle flow path from the injection zone to a layer formation zone;
• accumulating the particles in the layer formation zone to gradually form the particle layer on the gas-liquid interface;
• moving, from a location at least partly upstream of the injection zone, the movable barrier downstream along the particle flow path to promote the flow of the particles downstream along the particle flow path and push the particle layer toward and onto the transfer assembly for withdrawal of the same;
• and
• withdrawing, using the transfer assembly, the particle layer from the layer formation zone.

An apparatus for forming a particle layer, the apparatus comprising:

• a vessel for receiving a carrier liquid such that, when the carrier liquid is present in the vessel, the carrier liquid defines a gas-liquid interface with an ambient gas;
• an injection assembly configured to inject particles in an injection zone defined at the gas-liquid interface;
• a flow control assembly disposed in the vessel such that, when the carrier liquid is present in the vessel, the flow control assembly is submerged at least partly in the carrier liquid and configured to control a flow of the carrier liquid along the gas-liquid interface, the flow of the carrier liquid carrying the particles downstream along a particle flow path from the injection zone to a layer formation zone where the particles accumulate and gradually form the particle layer on the gas-liquid interface;
• a transfer assembly configured to withdraw the formed particle layer from the layer formation zone;
• and
• a barrier located at least partly upstream of the injection zone and configured to promote the flow of the particles downstream along the particle flow path, wherein the barrier is movable and configured to move downstream along the particle flow path to push the particle layer toward and onto the transfer assembly for withdrawal of the same.