Method and apparatus for digital fabrication of objects using actuated micropixelation and dynamic density control

Abstract

A fabrication device includes a build surface to receive layers of material for production of a 3-dimensional solid representation of a digital model and an imaging component to bind respective portions of the build material into cross sections representative of portions of data contained in the digital model. The imaging component may be a programmable planar light source utilizing a micropixelation system and refractive pixel shifting mechanism, or other imaging system. The device may include a system for controlling the density of the printed part. The object may be a powder composite component using any of a variety of powder materials or a plastic component. The object may be further post-processed to produce a high precision metal or ceramic component.

1 - 15 . (canceled) 
     
     
         16 . An imaging system comprising:
 an array of selectively activated illumination sources, wherein each of the array of illumination sources is configured to produce an image within a respective pixel area of a target surface, wherein an illuminated area covered by the image produced by each of the array of illumination sources is at least 20% smaller than a total size of the respective pixel area; and   an image shifting device for shifting the position of each image within the respective pixel area.   
     
     
         17 . The imaging system of  claim 16 , wherein the image shifting device comprises at least one rotatable refractive element. 
     
     
         18 . The imaging system of  claim 17 , wherein the image shifting device comprises two rotatable refractive elements that can shift the image along different axes. 
     
     
         19 . The imaging system of  claim 17 , wherein the image shifting device comprises at least two rotatable refractive elements with different indices of refraction that are calibrated to reduce chromatic aberration in each image. 
     
     
         20 . The imaging system of  claim 19 , wherein the image shifting device comprises four rotatable refractive elements configured for achromatic shifting along 2 axes. 
     
     
         21 . The imaging system of  claim 16 , wherein the array of illumination sources comprises:
 a DMD chip configured to reflect radiation from an incident light source; and   a microlens array configured to direct radiation from the DMD chip towards the target surface.   
     
     
         22 . The imaging system of  claim 16 , wherein array of illumination sources comprises a microLED array. 
     
     
         23 . The imaging system of  claim 16 , wherein the array of illumination sources comprises a combination of a large source and a LCD mask. 
     
     
         24 . The imaging system of  claim 17 , wherein the image shifting device is configured to shift the position of each image by a minimum shifting amount that is smaller than a largest dimension of the respective pixel area. 
     
     
         25 - 54 . (canceled) 
     
     
         55 . A method for fabricating a 3d object comprising:
 delivering a build material to a build surface;   selectively irradiating the build material to form a layer of the object, wherein irradiating the build material comprises the use of an array of illumination sources that produce an array of images in a plurality of rows at a surface of each layer, wherein a center-to-center distance between the array of images is larger than a width of each image, wherein each of the plurality of rows of images is offset from an adjacent row by a distance no greater than the width of each image, and wherein the plurality of rows comprise a number of rows sufficient to be linearly translated across a target area to completely image the target area.   
     
     
         56 . The method of  claim 55 , wherein:
 the build material comprises a blended composition of a powder material and a binder material; and   said selectively irradiating the build material comprises binding together at least a portion of the powder material into the layer.   
     
     
         57 . The method of  claim 56 , wherein said delivering the build material comprises:
 depositing the powder material on the build surface; and   infusing the binder material into the powder material.   
     
     
         58 . The method of  claim 56 , wherein said delivering the build material comprises depositing a slurry containing the blended composition of the powder material and the binder material on the build surface. 
     
     
         59 - 92 . (canceled) 
     
     
         93 . A system for fabricating a three-dimensional (3d) object, comprising:
 the imaging system of  claim 16 ; and   a material delivery system configured to deliver a build material to a build surface, wherein the build material comprises a blended composition of a powder material and a binder material, and wherein the imaging system is configured to selectively irradiate the build material to bind together at least a portion of the powder material into the layer.   
     
     
         94 . The system of  claim 93 , wherein said material delivery system is configured to:
 deposit the powder material on the build surface; and   infuse the binder material into the powder material.   
     
     
         95 . The system of  claim 93 , wherein said material delivery system is configured to deposit a slurry containing the blended composition of the powder material and the binder material on the build surface. 
     
     
         96 . The system of  claim 93 , wherein:
 the build material comprises a solid blend of a powder material and a binder material;   the material delivery system is configured to change a phase of the binder material; and   the imaging system is configured to selectively irradiate the build material to alter a physical state of a portion of the build material.   
     
     
         97 . The system of  claim 96 , wherein the solid blend comprises a film containing the powder material and the binder material. 
     
     
         98 . The system of  claim 97 , wherein the film comprises multiple layers, wherein one layer comprises a non-reactive, translucent imaging window. 
     
     
         99 . The system of  claim 97 , wherein changing a phase of the binder material comprises forming a melt pool from the film on the build surface, wherein the melt pool is conditioned into a uniform layer.