A team of engineers at Trinity College, Dublin are spearheading a project for the European Space Agency (ESA) aimed a fine-tuning a revolutionary 'Cold Spray' 3D printing technology.

The four-year-long project is tasked with refining the production and coating of mechanical structures with different materials using Cold Spray (CS) technology. They say the technique will find applications for household goods, in vehicle design and even on spacecraft.

This CS technology uses powders of various materials which are accelerated to supersonic speeds and then fired onto structures via a nozzle system. At this point, the technology is used to build simple geometrical components. The process allows for the use of materials including metals, polymers and composites, but the true appeal of the technique when compared to other 3D printing or additive manufacturing technologies is speed.

The Trinity College team says CS technology could well be 1,000 times faster in production than standard 3D printing techniques.

As it doesn't require heat which can result in micro-structural changes and distortions to the finished objects, the process also offers significant advantages over heat-dependent additive manufacturing methods.

The technique covers a wide variety of coating processes that can be used to apply metals, polymers, ceramics or cermets onto metallic, polymeric, composite or ceramic substrates.

Cold Spray is accomplished as feedstock material is propelled against a substrate with sufficient kinetic energy to produce a dense coating or create a free-form object, and it happens at relatively low temperatures.

The deposits produced by the method are oxide-free and fully dense in that they exhibit strong mechanical properties. A pressurized carrier gas like nitrogen or air is passed through what's known as a "DeLaval" convergent-divergent nozzle resulting in a supersonic gas jet from carrier gas expanding toward the exit of the nozzle.

The powdered spray material is then injected into the gas jet – either upstream or downstream – near the nozzle throat. Depending on the process temperature, each material requires a specific particle velocity to bond and deposit correctly.

At this point, the team says that the CS process is both inefficient and expensive. The $570,000 grant the Trinity College team received will be used to study ways to reduce the costs involved.

They add that CS technology will be used on aerospace projects such as ExoMars, the Solar Orbiter missions, the International Space Station, the James Webb Space Telescope and the Euclid mission.

One intriguing element of the technology is the ability it presents to designers to create novel, multi-material objects with enhanced surface properties.

Shaun McFadden, Rocco Lupoi, and Anthony Robinson

The project will be led by Dr. Rocco Lupoi, an Assistant Professor in Mechanical and Manufacturing Engineering at the Trinity College School of Engineering.

Lupoi says that once the pressing issues are addressed, this new form of cold spray manufacturing may well be the key to unlocking a range of capabilities in coated materials and multi-material combinations which are not possible with current methods.

"Engineering components usually start with a large piece of metal and this is reduced to the size and shape you need," says Lupoi. "Cold spray works like a painting machine, applying layer after layer to build up a shape, but done in a matter of seconds. You accelerate the gasses to supersonic velocity, and if you inject particles into the gas, they will also reach supersonic speeds. The particles are moving fast enough to penetrate into the surface and bond in a quick way so you can build up, say, five millimeters of material in a matter of seconds.”

Along with Lupoi, the project will be directed by Dr. Shaun McFadden and Dr. Anthony Robinson of Trinity, and the trio will collaborate with Professor David Jarvis, Andrea Amaldi and Dr. Wayne Voice from the technical staff at the ESA.

A team of engineers at General Electric are also working on similar 'cold spray' technology, and you can read about their work here.