Optical assembly for additive manufacturing

Abstract

An additive manufacturing apparatus includes a platform, a dispenser to deliver a layers of feed material onto the platform, one or more light sources to generate a first light beam and a plurality of second light beams, a galvo mirror scanner to scan the first light beam on a layer of feed material on the platform, and a plurality of polygon mirror scanners. The galvo mirror scanner has a first field of view that spans a width of a build area of the platform, whereas, each of the plurality of polygon mirror scanners having a second field of view with the plurality of polygon mirror scanners providing a plurality of second fields of view. Each second field of view is a portion of the first field of view, and the plurality of polygon mirror scanners are positioned such that the plurality of second fields of view span the width of the build area of the platform.

What is claimed is: 
     
         1 . An additive manufacturing apparatus comprising:
 a platform;   a dispenser configured to deliver a plurality of successive layers of feed material onto the platform;   one or more light sources to generate a first light beam and a plurality of second light beams;   a galvo mirror scanner to scan the first light beam on a layer of feed material on the platform, the galvo mirror scanner having a first field of view that spans a width of a build area of the platform; and   a plurality of polygon mirror scanners, each of the plurality of polygon mirror scanners having a second field of view with the plurality of polygon mirror scanners providing a plurality of second fields of view, wherein each polygon mirror scanner is configured to scan a respective second light beam in a scanning direction across the layer of feed material on the platform, wherein each second field of view is a portion of the first field of view, and wherein the plurality of polygon mirror scanners are positioned such that the plurality of second fields of view are positioned end-to-end along the scanning direction and span the width of the build area of the platform.   
     
     
         2 . The apparatus of  claim 1 , comprising an actuator to move an assembly including the galvo mirror scanner the plurality of polygon mirror scanners in a first direction across the platform. 
     
     
         3 . The apparatus of  claim 2 , wherein the plurality of polygon mirror scanners are configured to scan the plurality of second light beams along a linear path in the scanning direction perpendicular to the first direction. 
     
     
         4 . The apparatus of  claim 2 , wherein the first direction is perpendicular to the width of the build area. 
     
     
         5 . The apparatus of  claim 1 , comprising a frame supporting the galvo mirror scanner and the plurality of polygon mirror scanners such that the galvo mirror scanner and the plurality of polygon mirror scanner move with the frame. 
     
     
         6 . The apparatus of  claim 1 , wherein the galvo mirror scanner is configured to move the first light beam in two perpendicular directions across the build area and wherein the plurality of polygon mirror scanners are configured to scan the plurality of second light beams along linear paths. 
     
     
         7 . The apparatus of  claim 1 , wherein two adjacent second fields from the plurality of second fields partially overlap. 
     
     
         8 . The apparatus of  claim 7 , wherein two adjacent second fields from the plurality of second fields overlap by no more than about 25%. 
     
     
         9 . The apparatus of  claim 1 , comprising a controller configured to cause the galvo mirror scanner to scan the first light beams across the layer of feed material to fuse the feed material. 
     
     
         10 . The apparatus of  claim 9 , wherein the controller is configured to cause the plurality of polygon mirror scanners to scan the plurality of second light beams across the layer of feed material to pre-heat the layer of feed material before the layer of feed material is fused. 
     
     
         11 . The apparatus of  claim 9 , wherein the controller is configured to cause the plurality of polygon mirror scanners to scan the plurality of second light beams across the layer of feed material to heat-treat the layer of feed material after the layer of feed material is fused. 
     
     
         12 . The apparatus of  claim 1 , comprising a first housing positioned above the build plate and surrounding the first field of view and the plurality of second fields of view. 
     
     
         13 . The apparatus of  claim 12 , comprising a second housing surrounding the build plate and the first housing. 
     
     
         14 . The apparatus of  claim 13 , wherein the second housing forms a vacuum chamber.