Rotating relative recoater and part orientation

Abstract

A system for additive manufacturing includes a build chamber including a sidewall and a build plate cooperating to define a build volume, wherein the build chamber is configured to house a part and unfused feedstock powder during a build. An energy source is mounted for movement relative to the build chamber, wherein the energy source is configured to selectively sinter the feedstock powder. A recoater is mounted for movement relative to the build chamber, wherein the recoater is configured to deposit successive layers of the feedstock powder for sintering to the part. A rotational actuator is in operable communication with the build chamber and the recoater configured to rotate the build chamber relative to the recoater.

What is claimed is: 
     
         1 . A system for additive manufacturing comprising:
 a build chamber including a sidewall and a build plate cooperating to define a build volume, wherein the build chamber is configured to house a part and unfused feedstock powder during a build;   an energy source mounted for movement relative to the build chamber, wherein the energy source is configured to selectively sinter the feedstock powder;   a recoater mounted for movement relative to the build chamber, wherein the recoater is configured to deposit successive layers of the feedstock powder for sintering to the part; and   a rotational actuator in operable communication with the build chamber and the recoater configured to rotate the build chamber relative to the recoater.   
     
     
         2 . The system as recited in  claim 1 , further comprising a gas flow manifold operatively connected to a machine body for controlling gas composition in the build chamber, wherein the rotational actuator is configured to rotate the build chamber relative to the gas flow manifold and relative to the machine body. 
     
     
         3 . The system as recited in  claim 1 , further comprising a linear actuator configured to move the build plate relative to the sidewall of the build chamber, wherein the linear actuator and the rotary actuator each include a respective encoder, wherein the encoders are operatively connected to index part location and rotation to provide clearance between the part and the recoater for rotation of the build chamber. 
     
     
         4 . The system as recited in  claim 1 , wherein the rotational actuator includes an encoder configured to index rotational part position, wherein an index value from the encoder is used to confirm approach angle of the recoater. 
     
     
         5 . The system as recited in  claim 1 , further comprising a controller operatively connected to the energy source, to the recoater, and to the rotational actuator for controlling additive manufacturing of a part in the build chamber, wherein the controller is configured to select an approach angle on a layer by layer basis for the recoater relative to a build in the build chamber, wherein the approach angle for each layer is selected based on which approach angles provide a predetermined build quality. 
     
     
         6 . The system as recited in  claim 5 , wherein the recoater is a soft recoater which is configured to not make contact with a part in the build chamber during a build, wherein the controller is configured to select an approach angle on a layer by layer basis to reduce or eliminate ripples forming in the part due to interactions between the recoater and a melt pool formed in the part as the energy source sinters feedstock powder to the part. 
     
     
         7 . The system as recited in  claim 5 , wherein the recoater is a soft recoater which is configured to not make contact with a part in the build chamber during a build, wherein the controller is configured to select an approach angle on a layer by layer basis to reduce or eliminate cumulative build errors forming in the part due to interactions between the recoater and a melt pool formed in the part as the energy source sinters feedstock powder to the part. 
     
     
         8 . The system as recited in  claim 1 , wherein the build plate and the sidewall of the build chamber are configured to rotate together with a part during a build in the build chamber, and to rotate the part and unfused feedstock powder together in the build chamber to avoid relative rotation of the part and unfused feedstock powder. 
     
     
         9 . The system as recited in  claim 1 , wherein the rotational actuator is configured to rotate the build chamber clockwise and counter-clockwise. 
     
     
         10 . The system as recited in  claim 1 , wherein the build plate has a non-circular shape, and wherein the sidewall of the build chamber conforms to the non-circular shape. 
     
     
         11 . A method of additive manufacturing comprising:
 depositing feedstock powder with a recoater in a build chamber;   selectively sintering a portion of the feedstock powder deposited by the recoater to a part in the build chamber;   rotating the part, the build chamber, and unsintered feedstock powder in the build chamber together relative to the recoater; and   repeating the depositing, the selectively sintering, and the rotating to form an additively manufactured part layer by layer in the build chamber.   
     
     
         12 . The method as recited in  claim 11 , further comprising controlling gas composition in the build chamber using a gas flow manifold, wherein the rotational actuator is configured to rotate the build chamber relative to the gas flow manifold. 
     
     
         13 . The method as recited in  claim 11 , further comprising indexing part location and rotation to provide clearance between the recoater and the part for rotation of the build chamber. 
     
     
         14 . The method as recited in  claim 11 , using an index value from an encoder to confirm approach angle of the recoater. 
     
     
         15 . The method as recited in  claim 11 , further comprising selecting an approach angle on a layer by layer basis for the recoater relative to a build in the build chamber, wherein the approach angle for each layer is selected based on which approach angles provide a predetermined build quality. 
     
     
         16 . The method as recited in  claim 15 , wherein the recoater is a soft recoater and further comprising avoiding contact between the soft recoater with a part in the build chamber during a build, wherein avoiding contact includes selecting an approach angle on a layer by layer basis to reduce or eliminate ripples forming in the part due to interactions between the recoater and a melt pool formed in sintering feedstock powder to the part. 
     
     
         17 . The method as recited in  claim 15 , wherein the recoater is a soft recoater and further comprising avoiding contact between the soft recoater with a part in the build chamber during a build, wherein avoiding contact includes selecting an approach angle on a layer by layer basis to reduce or eliminate cumulative build errors forming in the part due to interactions between the recoater and a melt pool formed in the part in sintering feedstock powder to the part. 
     
     
         18 . The method as recited in  claim 11 , wherein rotating the part, the build chamber, and unsintered feedstock includes rotating the part and unsintered feedstock together to avoid relative rotation of the part and unfused feedstock powder. 
     
     
         19 . The method as recited in  claim 11 , wherein rotating the part, the build chamber, and unsintered feedstock includes rotating the build chamber clockwise and counter-clockwise. 
     
     
         20 . The method as recited in  claim 11 , wherein the build plate has a non-circular shape, and wherein the sidewall of the build chamber conforms to the non-circular shape.