US research institution Lawrence Livermore National Laboratory (LLNL) has managed to be the first to 3D-print a high-quality aerospace grade carbon (carbon fibre).
The breakthrough, according to the researchers, opens the door to better control and optimisation of the lightweight but rock-solid material. Carbon is typically stronger than steel.
"The mantra is: 'If you could make anything out of carbon, you would,'" said lead researcher Jim Lewicki on LLNL's website. "Potentially, carbon is the ultimate material. It has been waiting behind the scenes for years because it is difficult to make carbon into complex shapes. But with 3D printing, you can basically make anything out of carbon."
Complex structures
Carbon is a lightweight yet rigid and strong material that resists temperature well. This makes the composite particularly suitable for aerospace, defence, automotive and sports (e.g. surfing and motorbike racing).
Carbon composites are normally manufactured in two ways: by physically wrapping the filaments around a spindle or by weaving the fibres together like a wicker basket, resulting in a final product that is either flat or cylindrical.
LLNL researchers have now succeeded in printing complex 3D structures from carbon using a technique called Direct Ink Writing (DIW). Among other things, the institute printed a part of a racket nose from carbon.
Lewicki and his team have also additionally developed a new chemical compound that allows material to be repaired in seconds, where it normally takes hours.
Simulation
Simulation formed a key part of the technology. Engineers simulated thousands of carbon fibres to check how they came off the nozzle to determine how best to align them.
"We developed a numerical code that simulates a non-Newtonian fluid polymer resin with a dispersion of carbon fibres. This code allows us to simulate the evolution of fibre orientations in 3D under different prints," says analyst liquid Yuliya Kanarska." We were able to find the optimal fibre length and performance, but it is still a work in progress. Ongoing efforts relate to achieving even better alignment of the fibres by applying magnetic forces to stabilise them."
This technology allows them to start developing specific carbon fibre materials for specific applications. Direct Ink Writing also makes it possible to print parts where all carbon fibres are in the same direction. According to the researchers, this means two-thirds less carbon fibre is needed but with the same properties as traditional carbon.
The researchers will now optimise the process and see what are the best places to deposit the carbon fibre. Talks have already been held with aviation companies, among others.
You can read a detailed (in English) account of the creation of the 3D-printed carbon at http://www.nature.com/articles/srep43401.
Also watch the video about the technique here: https: //youtu.be/jfFpd4ZQ0Ic
Source: Lawrence Livermore National Laboratory (LLNL)
By: Kelly Bakker
