Abstract: A method for detecting defects includes steps of: (1) calculating an average value for intensity of CT image voxels in a neighborhood; (2) calculating a difference value for the intensity of the voxels in the neighborhood; (3) calculating a standard deviation for the intensity of the voxels in the neighborhood; (4) calculating a z-score for each one of the voxels; (5) identifying a cluster of neighboring ones of the voxels; (6) determining a cluster-boundary parameter of the cluster; and (7) classifying the cluster as a defect when the cluster-boundary parameter of the cluster is above a parameter threshold.

Abstract: An apparatus includes a wall that defines a shaft, a powder platform configured to support a powder bed within the shaft and configured to move through the shaft, and a sealing device that is in a compressed state from an outer perimeter of the sealing device to an inner perimeter of the sealing device such that the outer perimeter contacts the wall and the inner perimeter contacts the powder platform to form a seal between the powder platform and the wall. Another apparatus includes a wall that defines a shaft, a powder platform configured to support a powder bed within the shaft and configured to move through the shaft, and a sealing device comprising a non-fibrous material that is affixed to the powder platform and extends away from the powder platform, the sealing device contacting the wall to form a seal between the powder platform and the wall.

Abstract: An apparatus includes a wall that defines a shaft, a powder platform configured to support a powder bed within the shaft and configured to move through the shaft, and a sealing device that is in a compressed state from an outer perimeter of the sealing device to an inner perimeter of the sealing device such that the outer perimeter contacts the wall and the inner perimeter contacts the powder platform to form a seal between the powder platform and the wall. Another apparatus includes a wall that defines a shaft, a powder platform configured to support a powder bed within the shaft and configured to move through the shaft, and a sealing device comprising a non-fibrous material that is affixed to the powder platform and extends away from the powder platform, the sealing device contacting the wall to form a seal between the powder platform and the wall.