In-Process Quality Assessment for Additive Manufacturing

An apparatus comprising:

• an eddy current sensor array with a linear drive winding and a linear array of sensing elements;
• a powder bed holding a plurality of additive manufacturing (AM) layers including a most recently deposited layer and a previously deposited layer;
• a scanner to which the sensor array is attached configured to scan the sensor array across the powder bed;
• an impedance instrument having fully parallel sensing hardware electrically connected to the eddy current sensory array to simultaneously measure a response of the eddy current sensor array on each sensing element while the scanner scans the sensor array across the powder bed;
• a processor;
• and
• a non-transient computer-readable storage medium having computer code modules executable by the processor, the computer code modules including
• a property estimation module having computer-executable code to perform a multivariate inverse method that utilizes a precomputed database to convert the response of each sensing element into a value of a material property for the most recently deposited layer.

An apparatus comprising:

• an eddy current sensor array with a linear drive winding and a linear array of sensing elements;
• a powder bed holding a plurality of additive manufacturing (AM) layers including a most recently deposited layer and a previously deposited layer;
• a scanner, to which the sensor array is attached, configured to scan the sensor array across the powder bed;
• an impedance instrument having fully parallel sensing hardware electrically connected to the eddy current sensory array to simultaneously measure responses of the eddy current sensor array on each sensing element at each of a plurality of frequencies while the scanner scans the sensor array across the powder bed;
• a processor;
• and
• a non-transient computer-readable storage medium having
• a precomputed database of sensor responses for a plurality of unknown quantities generated from a model of the eddy current sensor array and the AM layers, the plurality of unknown quantities including a material property for the most recently deposited layer and a lift-off of the eddy current sensor array from the most recently deposited layer, and
• computer code modules executable by the processor, the computer code modules including a property estimation module having computer-executable code to perform a multivariate inverse method that utilizes the precomputed database to convert the responses of each sensing element into estimated values of the material property for the most recently deposited layer, a material property of the previously deposited layer, and the lift-off.

A method comprising:

• first moving an eddy current sensor array relative to a powder bed holding a plurality of additive manufacturing (AM) layers including a first top layer, the eddy current sensor array having at least one linear array of sensing elements;
• during the first moving, measuring first responses of the sensing elements while the eddy current sensor array moves relative to the powder bed over the first top layer;
• after measuring the first responses, adding to the plurality of AM layers by depositing a most recently deposited layer on top of the first top layer;
• after depositing the most recently deposited layer, second moving the eddy current sensor array relative to the powder bed;
• during the second moving, measuring second responses of the sensing elements while the eddy current sensor array moves relative to the powder bed over the most recently deposited layer;
• storing on a non-tranient computer-readable storage medium a precomputed database of sensor responses for a plurality of unknown quantities of the AM layers, the plurality of unknown quantities including a material property for the most recently deposited layer;
• and
• operating a processor to estimate values of a material property of the most recently deposited layer using at least the precomputed database, the first response, and at least one of the second response and a change between the first response and second response.