An additive manufacturing system includes an energy source and a material delivery device. The energy source is configured to direct an energy beam toward a component to form a melt pool. The material delivery device is configured to feed a wire toward the melt pool to deposit material on the component. In some examples, the material delivery device is configured to discharge a current to the wire to disengage the wire from the melt pool. In some examples, the material delivery device is configured to measure an arc voltage between the wire and the component.