Syntactic foam is a mixture of microscopic hollow glass or ceramic spheres in plastic resin or epoxy. It is widely used in submarines and because it has a high level of strength and buoyancy.
A group of scientist at NYU Tandon School of Engineering have found a way to 3D print components made of syntactic foam. This is a game changer for the deep sea exploration community because it allows them a way to 3D print complex shapes that are capable of surviving pressures at great depth.
Currently, syntactic foam parts are made by injection molding and the parts must be joined by adhesives. This can cause weak points in the design. 3D printing can eliminate the use of adhesives making the parts stronger. The researchers developed filaments of high-density polyethylene plastic (HDPE), a material used to manufacture industrial-grade components, and microspheres made of recycled fly ash.
The difficult part was finding a way to mix the large abount of microspheres without crushing them. The process required the team to minimize crushing of the fragile hollow particles during mixing with the HDPE resin so that the resulting filament could have low density.
Now, the focus is on optimizing the material for various applications like underwater vehicles capable of functioning at specific depths.