Pneumatic Powder Transport System
View Patent ↗A method and apparatus for pneumatic powder transfer from a powder supply container to applications such as laser sintering systems. The method and apparatus use both constant and cyclic flows of a pressurized gas to fluidize and convey powders without the need for any tilting unloading stands, vibration or other mechanical working of the powder.
1. A method for producing a bed of powder in a process chamber of a laser sintering machine in which a three-dimensional article is formed in layerwise fashion comprising the steps of:
(a) pneumatically feeding a virgin powder from a virgin powder container into a powder processing unit;
(b) pneumatically feeding powder from the powder processing unit into a feed hopper in the laser sintering machine;
(c) depositing a first portion of powder from the feed hopper into the process chamber and across a target area; and wherein the step of pneumatically feeding a virgin powder from a virgin powder container into a powder processing unit comprises the steps of:
i. fluidizing the virgin powder in the virgin powder container with a first flow rate of a first supply of compressed gas;
ii. intermittently pressurizing the virgin powder container with a second higher flow rate of the first supply of compressed gas; and
iii. removing a fluidized stream of the powder from a bottom outlet of the virgin powder container.
2. The method for producing a bed of powder in the process chamber of a laser sintering machine of claim 1 further comprising the step of augmenting the fluidized stream of the powder with a second supply of compressed gas.
3. The method for producing a bed of powder in the process chamber of a laser sintering machine of claim 1 further comprising depositing a first portion of powder across the target area in the process chamber from a first side to an opposing second side of the process chamber.
4. The method for producing a bed of powder in the process chamber of a laser sintering machine of claim 3 further comprising depositing a second portion of powder across the target area in the process chamber from the opposing second side to the first side.
5. A method for producing a bed of powder in a process chamber of a laser sintering machine in which a three-dimensional article is formed in layerwise fashion comprising the steps of:
(a) pneumatically feeding a virgin powder from a virgin powder container into a feed hopper in the laser sintering machine;
(b) depositing a first portion of powder from the feed hopper into the process chamber and across a target area; and
wherein the step of pneumatically feeding a virgin powder from a virgin powder container into a feed hopper in the laser sintering machine comprises the steps of:
i. fluidizing the virgin powder in the virgin powder container with a first flow rate of a first supply of compressed gas;
ii. intermittently pressurizing the virgin powder container with a second higher flow rate of the first supply of compressed gas; and
iii. removing a fluidized stream of the powder from a bottom outlet of the virgin powder container.
6. The method for producing a bed of powder in the process chamber of a laser sintering machine of claim 5 further comprising the step of augmenting the fluidized stream of the powder with a second supply of compressed gas.
7. The method for producing a bed of powder in the process chamber of a laser sintering machine of claim 5 further comprising depositing a first portion of powder across the target area in the process chamber from a first side to an opposing second side of the process chamber.
8. The method for producing a bed of powder in the process chamber of a laser sintering machine of claim 7 further comprising depositing a second portion of powder across the target area in the process chamber from the opposing second side to the first side.
9. A method for transferring a powder from a pneumatic powder transfer system comprising the steps of:
(a) connecting a container to supply powder to the pneumatic powder transfer system;
(b) fluidizing the powder in the pneumatic powder transfer system with a first flow rate of a first supply of compressed gas;
(c) intermittently pressurizing the container with a second higher flow rate of the first supply of compressed gas; and
(d) removing a fluidized stream of the powder from a bottom outlet of the container.
10. The method for transferring a powder from a pneumatic powder transfer system of claim 9 further comprising the step of augmenting the fluidized stream of the powder with a second supply of compressed gas.