Multiple image projection method for additive manufacturing
An additive manufacturing system, and associated methods, comprise an image projection system comprising a plurality of image projectors that project a composite image onto a build area within a resin pool. The composite image comprises a plurality of sub-images arranged in an array. The properties of each sub-image and the alignment of the position of each sub image within the composite image can be adjusted using a stack of filters comprising: 1) an irradiance mask that normalizes irradiance, 2) a gamma adjustment mask that adjusts sub-image energy based on a reactivity of the resin, 3) a warp correction filter that provides geometric correction, and 4) an edge blending bar at one or more sub-image edges.
1. A method comprising:
a. providing an additive manufacturing system, comprising:
an image projection system comprising a plurality of image projectors; and
an image display subsystem;
b. projecting a composite image onto a build area within a resin pool using the image projection system, wherein:
the image projection system is controlled by the image display subsystem;
the composite image comprises a plurality of sub-images arranged in an array;
two or more adjacent sub-images in the array overlap at two or more sub-image edges; and
each sub-image is projected onto a portion of the build area using one of the plurality of image projectors; and
c. adjusting properties and aligning a position of each sub-image in the array using a set of filters comprising:
an irradiance mask that normalizes irradiance;
a gamma adjustment mask that adjusts sub-image energy based on a reactivity of resin in the resin pool;
a warp correction filter that provides geometric correction; and
an edge blending bar at one or more sub-image edges.
2. The method of claim 1 , wherein the image display subsystem controls the image projection system and each of the image projectors using digital light processing.
3. The method of claim 1 , wherein the irradiance mask additionally adjusts the energy across the build area to compensate for non-uniformities in optics of the plurality of image projectors.
4. The method of claim 1 , wherein the gamma adjustment mask comprises a logarithmic relationship between a cure depth of the resin and energy per unit area in the build area.
5. The method of claim 1 , wherein the resin is selected from the group consisting of acrylates, epoxies, methacrylates, urethanes, silicone, vinyls, and combinations thereof.
6. The method of claim 1 , wherein the edge blending bar comprises a blending distance and a function selected from the group consisting of: linear, sigmoid and geometric.
7. The method of claim 1 , wherein the edge blending bar adjusts the one or more sub-image edges based on at least one layer boundary location within an object being manufactured.
8. The method of claim 1 , further comprising a system controller that synchronizes exposure control of the plurality of image projectors with each other.
9. The method of claim 1 , wherein the projecting the composite image further comprises moving the plurality of sub-images during an exposure of a layer of an object being manufactured.
10. The method of claim 9 , wherein the movement of the sub-images is either a step-expose-step type movement or a continuous movement.
11. The method of claim 9 , wherein:
the plurality of sub-images comprises a 1D array of sub-images oriented in a first direction; and
the movement of the sub-images is in a second direction perpendicular to the first direction.
12. The method of claim 9 , wherein:
the plurality of sub-images comprises a 2D array of sub-images with rows oriented along a first direction and columns oriented along a second direction; and
the movement of the sub-images is in either one of the first or second directions, or both the first and second directions.
13. The method of claim 9 , wherein:
the plurality of sub-images arranged in the array comprises one or more rows oriented along a first direction and one or more columns oriented along a second direction; and
the movement of the sub-images is in a third direction that is different from both the first and second directions.
14. The method of claim 1 , wherein the adjusting properties and aligning the position of each sub-image in the array further comprises applying the irradiance mask to each sub-image such that the composite image has a uniform irradiance range across the composite image.
15. The method of claim 1 , wherein the adjusting properties and aligning the position of each sub-image in the array further comprises applying the irradiance mask to each sub-image to normalize irradiance non-uniformities within the image projection system arising from a projector-based spatial energy non-uniformity.