Additive Manufacturing

Sometimes referred to as 3D printing, additive manufacturing is more properly understood as encompassing a variety of manufacturing processes. In AM, objects are created by precisely adding layer-upon-layer of material according to a specific design, whether the material is plastic, metal, ceramic, or something else. AM has rapidly become widely utilized tool because of its ability to create geometries and features that are difficult or impossible to achieve through traditional methods such as machining, especially when creating very small objects.

General Atomics’ Inertial Fusion Technologies division employs a specific AM method known as two-photon-polymerization (2PP), among other techniques, in its target manufacturing activities. In 2PP, focused, ultrashort laser pulses are directed into a volume of photosensitive material, or photoresist. The laser pulses cause polymerization in the photoresist, and by illuminating a specific three-dimensional region, solid structures can be created and remain behind when the unilluminated material is washed out. The name comes from the specific chemical reaction, which involves polymerization through absorption of two photons at time. 2PP is capable of creating ultra-high resolution features on the order of ≤1 µm. GA has developed 2PP technology that can produce faster results with fewer defects over larger regions than competing methods.

am-2PP_video.mov

This video shows GA’s advanced 2PP printing technology using multifocal parallel processing.

GA also employs a similar, low-temperature technique for 3D printing at high resolution (sub-micron) scale of pure metal features directly onto substrates. Even a delicate substrate such as few-micron-thick polypropylene films may be written upon. We can write using such elements as gold and silver.

GA 3D-printed metal grids in silver (L, C) and gold (R)
GA 3D-printed metal grids in silver (L, C) and gold (R). The individual strands are approximately 2 µm thick.

GA is currently developing technology to print pure carbon-hydrogen elements at sub-micron scale. This will be applied to advance GA IFT’s world-leading target fabrication capabilities among other efforts.