What exactly is 3D printing and how does it work?

Jon Lawson

The origins of modern 3D printing lie in a process called stereolithography, created in the 1980s. The process starts with the computer aided design (CAD) file, which is sliced electronically into layers, each layer is then printed with a laser solidifying a photo-sensitive gel. The polymer parts made were never intended for series production, more originally for tasks like checking real world ergonomics and part fitment.

Meanwhile, other processes were taking shape. One example if this is fused deposition modelling, or FDM, as pioneered by firms like Stratasys. 

An early example of a 3D printing success

By the mid 1990s NASA was experimenting with 3D printers. 

On a training exercise an astronaut was submerged in a pool simulating zero gravity on a space walk, with a mock up of a satellite to repair.

The spanner he was using kept floating to the bottom of the pool. They tried a different milled plastic and it floated to the top. To recreate zero gravity, the spanner should float in place where it was left.

By adjusting the density of the plastic on an FDM printer, they got it to float without moving so the exercise could better replicate conditions in space.

What are the other advantages of 3D printing?

One obvious one is that shapes can be made that are impossible for conventional machining. So, forms can be made inside each other, for example. 

Also one-off intricate items can be made quickly, useful for perfecting surgical techniques for example. It also uses less material than subtractive manufacturing methods.

As time has passed the machines have got cheaper and this trend will likely continue, increasing their adoption.

Are 3D printer materials sustainable?

The company 6K has launched powders derived from sustainable sources. The process has the ability to convert machined millings, turnings and other recycled feedstock sources into premium AM-ready metal powder. 

Also there is interest in biodegradable filament materials, and bioplastics derived from natural materials such as sea weed. 

What can be made by 3D printing?

The Bloodhound world land speed record attempt car has two 3D printed components, a titanium nose tip and steering wheel. The vehicle reached a speed of 628 mph on the 12.4-mile Hakskeen Pan track in the South African desert in November. 

Ogle models recently produced an intricate 3D model of a valve train system to demonstrate the design at trade shows. The designer, Camcon Automotive, wished to have a realistic scale model of its new solenoid technology dubbed iVT (intelligent Valve Technology) system. 

It was made using selective laser sintering (SLS) with tolerances of +/- 0.12mm per 100mm. 

Comic Jay Leno uses a 3D printer to create parts for classic cars. “I’m always looking to push the boundaries of what’s possible in creation and re-creation of these vehicles – and 3D printing is integral to this process,” he says.

Looking forward, NASA has awarded a US$73.7 million contract to Made In Space, a California company, to demonstrate the ability of a small spacecraft, called Archinaut One, to manufacture and assemble spacecraft components in low-Earth orbit, with a view to using the technology on the Moon to Mars mission.


Read more about how the transport industry could benefit here.