Characterizing liquid reflective surfaces in 3D liquid metal printing

A three-dimensional (3D) printer configured to print a 3D object, the 3D printer comprising:

• a nozzle;
• a camera configured to capture a plurality of real images of a plurality of drops of liquid metal while the drops are positioned at least partially within the nozzle, wherein each drop comprises a meniscus;
• and
• a computing system configured to:
• generate a parametric model of motion of the menisci of the drops positioned at least partially within the nozzle based at least partially upon the real images;
• generate a plurality of simulated images of the drops positioned at least partially within the nozzle based at least partially upon the parametric model;
• generate a labeled dataset that comprises the simulated images and a first set of parameters;
• inverse map the real images to a second set of parameters, based at least partially upon the labeled dataset;
• reconstruct the menisci of the drops in the real images based at least partially upon the second set of parameters;
• extract one or more metrics from the reconstructed menisci of the drops, wherein the metrics comprise a carrier oscillation frequency, a pulse-to-pulse covariance, a waveform decay rate, or a combination thereof;
• and
• adjust one or more parameters of the 3D printer based at least partially upon the one or more metrics to adjust the menisci of the drops positioned at least partially within the nozzle.

A three-dimensional (3D) printer configured to print a 3D object by jetting a plurality of drops of liquid metal of onto a substrate, the 3D printer comprising:

• an ejector comprising a nozzle;
• a heating element configured to heat a solid metal within the ejector, thereby converting the solid metal to the liquid metal;
• a coil wrapped at least partially around the ejector;
• a power source configured to transmit voltage pulses to the coil, wherein the coil causes the plurality of drops of the liquid metal to be jetted through the nozzle in response to the voltage pulses;
• a camera configured to capture a plurality of real images of the drops while the drops are positioned at least partially within the nozzle, wherein each drop comprises a meniscus;
• a light source configured to illuminate the nozzle and the drops as the real images are captured;
• and
• a computing system configured to:
• generate a parametric model of dynamic motion of the menisci of the drops positioned at least partially within the nozzle based at least partially upon the real images;
• generate a plurality of simulated images of the drops positioned at least partially within the nozzle based at least partially upon the parametric model;
• generate a labeled dataset that comprises the simulated images and a first set of parameters, wherein the first set of parameters comprises:
• a first relative weight of a first Bessel function that describes an oscillation of the liquid;
• a second relative weight of a second Bessel function that describes the oscillation of the liquid;
• a constant offset;
• and
• a constant representing a steady state shape of the meniscus at rest;
• inverse map the real images to a second set of parameters, based at least partially upon the labeled dataset, wherein inverse mapping comprises:
• training an artificial neural network using the labeled dataset to predict the second set of parameters in the real images;
• or
• selecting an entry in the labeled dataset that is most similar, in mean-square error, to the real images using direct nearest-neighbor matching;
• reconstruct the menisci of the drops in the real images based at least partially upon the second set of parameters;
• extract one or more metrics from the reconstructed menisci of the drops, wherein the metrics comprise a carrier oscillation frequency, a pulse-to-pulse covariance, and a waveform decay rate;
• and
• adjust one or more parameters of the 3D printer based at least partially upon the one or more metrics to adjust a shape, an amplitude, or both of the menisci of the drops positioned at least partially within the nozzle.