SYSTEM AND METHODS FOR PRINTING DEFECT DETECTION
An additive manufacturing method includes depositing a first amount of metal powder onto a powder bed of a printing system, spreading the first amount of metal powder across the powder bed to form a first layer, and depositing a first amount of binder material on the first layer. The additive manufacturing method also includes exposing the first layer to a first lighting condition, imaging the first layer under the first lighting condition to generate a first image, analyzing the first image of the first layer, and determining whether to adjust at least one printing parameter based on the analyzing.
1 . A method of detecting and ameliorating defects during metal additive manufacturing, comprising the steps of:
spreading a metal powder on a powder bed of a metal additive manufacturing system and depositing a predetermined pattern of binder to the metal powder to form a layer of a green part; illuminating the layer of the green part with a first light source;
capturing via an imaging device a first image of the illuminated layer of the green part;
analyzing the first image and identifying a first defect in the layer of the green part; and
adjusting at least one printing parameter in response to identifying the first defect to ameliorate the first defect.
2 . The method of claim 1 wherein an axis of the first light source is angled with respect to the powder bed by 1 degree to 10 degrees.
3 . The method of claim 1 wherein an axis of the first light source is angled with respect to the powder bed by 70 degree to 110 degrees.
4 . The method of claim 1 wherein the defect is one of a blister, a divot, beading, a smear and a jet-out condition.
5 . The method of claim 1 wherein the step of analyzing includes identifying at least one shadow in the first image.
6 . The method of claim 1 , wherein the step of analyzing includes identifying at least one region that is brighter than an average brightness of the layer of the green part.
7 . The method of claim 1 wherein the step of analyzing includes detecting a bright spot and an associated shadow.
8 . The method of claim 1 wherein step of analyzing includes detecting at least one of a region of missing binder material, a bright region and a shadow in the first image.
9 . The method of claim 1 wherein the printing parameter is one of a vapor deposition rate, a binder deposition rate, and a negative feature pattern.
10 . The method of claim 1 , further comprising the steps of:
illuminating the layer of the green part with a second light source;
capturing via a second imaging device a second image of the illuminated layer of the green part;
analyzing the second image and identifying a second defect in the layer of the green part; and
adjusting at least one printing parameter in response to identifying the second defect to ameliorate the second defect.
11 . A method of detecting defects during metal additive manufacturing, comprising the steps of:
spreading a metal powder on a powder bed of a metal additive manufacturing system and depositing a predetermined pattern of binder to the metal powder to form a layer of a green part;
generating a first illumination condition and capturing a first image of the illuminated layer of the green part with a first imaging device;
generating a second illumination condition and capturing a second image of the illuminated layer of the green part with a second imaging device; and
comparing the first image and second image to at least one of each other, a design file and a third image and identifying a first defect in the layer of the green part.
12 . The method of claim 11 wherein an axis of the first light source is angled with respect to the powder bed by 1 degree to 10 degrees.
13 . The method of claim 12 wherein an axis of the second light source is angled with respect to the powder bed by 70 degree to 110 degrees.
14 . The method of claim 11 wherein the defect is one of a blister, a divot, a smear, beading and a jet-out condition.
15 . The method of claim 11 wherein the step of analyzing includes identifying at least one shadow in one of the first image and second image.
15 . The method of claim 11 , wherein the step of analyzing includes identifying at least one region that is brighter than an average brightness of the layer of the green part.
16 . The method of claim 11 wherein the step of analyzing includes detecting a bright spot and an associated shadow.
17 . The method of claim 11 wherein step of analyzing includes detecting at least one of a region of missing binder material, a bright region and a shadow in one of the first image and the second image.
18 . The method of claim 11 wherein the printing parameter is one of a vapor deposition rate, a binder deposition rate, and a negative feature pattern.
19 . The method of claim 11 wherein the third image is an image of a preceding layer in the green part.
20 . A method of identifying and clearing clogged jetting orifices in a binder jetting metal additive manufacturing system, comprising the steps of:
spreading from a printhead a metal powder on a powder bed of a metal additive manufacturing system and depositing a predetermined pattern of binder to the metal powder to form a layer of a green part;
illuminating the layer of the green part with a high angle light source;
capturing an image of the illuminated layer of the green part with an imaging device;
identifying areas of unbound powder according to the brightness an amount of reflected light;
comparing the areas of unbound powder to a design file and identifying a defect indicating a jet-out condition; and
subjecting the printhead to a maintenance cycle.