# US 7,464,733 B2 · Pneumatic Powder Transport System

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- Number: US 7,464,733 B2
- Document ID: US7464733B2
- Status: Granted
- Kind: B2
- Application number: 11/869,782
- Filed: 2007-10-10
- Published: 2008-02-21
- Granted: 2008-12-16
- Earliest claimed: 2005-03-31
- Assignees: 3D Systems, Inc.
- Inventors: Brian D. Cox
- Web page: https://patentgrep.com/patent/US7464733B2

## CPC

- B65G 53/22: the systems comprising a reservoir, e.g. a bunker
- B22F 12/52: Hoppers
- B33Y 30/00: Apparatus for additive manufacturing; Details thereof or accessories therefor
- B33Y 40/00: Auxiliary operations or equipment, e.g. for material handling
- B22F 12/41: characterised by the type, e.g. laser or electron beam
- B22F 12/44: characterised by the configuration of the radiation means
- B22F 12/49: Scanners
- B22F 2998/00: Supplementary information concerning processes or compositions relating to powder metallurgy
- B29C 64/329: using hoppers
- Y02P 10/25: Process efficiency
- B65G: TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS (packaging B65B; handling thin or filamentary materials, e.g. paper sheets or thread, B65H; cranes B66C; portable mobile or lifting or hauling appliances, e.g. hoists, B66D; devices for lifting or lowering goods for loading or unloading purposes, e.g. fork-lift trucks, B66F9/00; emptying bottles, jars, casks, barrels or similar containers, not otherwise provided for, B67C9/00; delivering or transferring liquids B67D; filling or discharging vessels for liquefied, solidified or compressed gases F17C; pipe-line systems for fluids F17D)
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B33Y: ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

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.

## Claims

### Claim 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.

### Claim 2 (depends on 1)

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.

### Claim 3 (depends on 1)

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.

### Claim 4 (depends on 3)

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.

### Claim 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.

### Claim 6 (depends on 5)

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.

### Claim 7 (depends on 5)

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.

### Claim 8 (depends on 7)

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.

### Claim 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.

### Claim 10 (depends on 9)

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.