SYSTEMS AND METHODS FOR MODELLING ADDITIVELY MANUFACTURED BODIES

摘要

Methods for creating three-dimensional volume quality models of additively manufactured metal bodies are disclosed. In one embodiment, a method comprises additively manufacturing each metal layer of a metal body. One or more images of the first metal layer are obtained. The image(s) are processed to detect and map potential manufacturing defects in the first metal layer. A two-dimensional contour of the first metal layer is generated from the three-dimensional CAD model. The mapped defects are integrated into the two-dimensional contour. A first layer of a three-dimensional volume quality model of the metal body is created based on the integrated two-dimensional contour.

主权项

1. A method comprising:
(A) spreading a first layer of metal powder on a powder bed; (B) selectively melting at least a portion of the first layer of metal powder, thereby forming a melt pool comprising molten metal of the metal powder; (C) solidifying the molten metal into a first metal layer of a metal body; (D) spreading a second layer of metal powder on the powder bed; (E) obtaining a first digital image of at least a portion of the powder bed;
wherein the first digital image has a plurality of pixels;wherein each pixel of the plurality of pixels has a specific intensity value; (F) translating the first digital image into a first binary image, wherein the translating comprises:
(i) determining a global average intensity value of the plurality of pixels;(ii) resetting any specific intensity value that exceeds a threshold value to be equal to the global average intensity value;(iii) determining a local average intensity value for each pixel of the plurality of pixels;(iv) subtracting the specific intensity value of each pixel of the plurality of pixels from the local average intensity value, thereby determining a background-corrected intensity value for each pixel of the plurality of pixels;(v) replacing the specific intensity value of each pixel with its determined background-corrected intensity value; and(vi) performing a thresholding operation on the digital image, thereby creating the first binary image;wherein the first binary image has a plurality of binary pixels;wherein the plurality of binary pixels comprises a plurality of particles; (G) filtering non-drag particles from the first binary image, wherein the filtering comprises:
(i) performing an x-axis close operation on each binary pixel of the plurality of binary pixels;(ii) removing from the first binary image all particles having a particle width below a threshold width;(iii) removing from the first binary image all particles having a particle elongation ratio below a threshold ratio;(iv) performing a dilation operation on the first binary image;(v) determining the number of on-pixels in each row of the first binary image;(vi) determining the number of particles in each row of the first binary image(vii) switching any on-pixels to off-pixels for any pixels in a row of the first binary image where the row has either a number of on-pixels less than a threshold on-pixel number, or a number of particles greater than a threshold particle number; (H) identifying all remaining particles in the first binary image as drag particles associated with the spreading a second layer step (D); (I) mapping the drag associated with the spreading a second layer step (D), wherein the mapping comprises:
(i) determining a location of each drag particle in the first binary image,(ii) determining a size of each drag particle, wherein a total number of pixels comprising each drag particle is representative of the size of each respective drag particle;(iii) mapping the location and size of each drag particle to a respective location in the powder bed; (J) creating a first layer of a three dimensional volume quality model of the metal body based at least in part on the location and size of each drag particle associated with the spreading a second layer step (D).