A research team has designed a new style of 3D printing which is able to print combined materials using ultrasonic waves. The engineers, based at the University of Bristol, demonstrated the novel method in which ultrasound is used to position millions of microscopic glass fibers into a tiny reinforcement framework. The layer is then placed using a focused laser beam, which cures the epoxy resin and prints the object.

The study explains how the researchers mounted a switchable, focused laser module onto the carriage of a conventional 3D printer, above the new ultrasonic alignment equipment.

In the test, a print speed of 20mm/s was achieved – comparable to the speed of a standard 3D printer. The engineers showed the ability to build a plane of fibers into a reinforcement framework, and precisely orientate the fibers by switching the ultrasonic standing wave pattern during the printing process.

This technique allows for the creation of almost any type, size or shape of fiber, including complex fibrous architectures, such as those required in high-performing products (tennis rackets, golf clubs, aerospace components, and fishing rods etc).

​Short explaining video for the process:

​Researchers in the US have developed a ceramic resin that enables the 3D printing of higher strength, higher temperature components suitable for applications in jet engines, microelectromechanical systems and possibly hypersonic vehicles.

The resin, which has been developed at HRL Laboratories, can be 3D printed into parts of virtually any shape and size, enabling complex, curved and porous ceramic components. The printed resin can then be fired, converting it into a high strength, fully dense ceramic.

The resulting material can withstand ultrahigh temperatures in excess of 1700°C and exhibits strength ten times higher than similar materials.

Previously, The extremely high melting point of many ceramics adds challenges to additive manufacturing as compared with metals and polymers. But now, the invented preceramic monomers are cured with ultraviolet light in a stereolithography 3D printer forming 3D polymer structures that can have complex shape and cellular architecture. These polymer structures can be pyrolyzed to a ceramic with uniform shrinkage and virtually no porosity by heating. The used silicon oxycarbide microlattice and honeycomb cellular materials fabricated with this approach exhibit higher strength than ceramic foams of similar density. 

Additive manufacturing of such materials is of interest for propulsion components, thermal protection systems, porous burners, microelectromechanical systems, and other applications.

Note:
Polymer-derived ceramics were discovered in the 1960s. upon heat treatment (typically under inert atmosphere), they pyrolyze into SiC, Si3N4, BN, AlN, SiOC, SiCN, BCN, or other compositions, whereas volatile species (CH4, H2, CO2, H2O, and hydrocarbons) leave the material. By attaching thiol, vinyl, acrylate, methacrylate, or epoxy groups to an inorganic backbone such as a siloxane, silazane, or carbosilane, ultraviolet (UV)–active pre-ceramic monomers can be obtained.

Video:

Missouri University of Science and Technology researchers are developing materials not currently in existence with the aid of additive manufacturing technology.

The benefit is that these materials are stronger and lighter than conventional ones and may be less expensive and more efficient to manufacture. The researchers call their process "Cyber Manufacturing Technology", and it includes additive manufacturing process modeling, sensor network and seamless process integration.

The materials that result from this cyber manufacturing are known as Structural Amorphous Metals - SAMs. Like other powder-based additive manufacturing techniques, a laser melts blown powder metal that is deposited layer by layer to  create objects. The key is to get the cooling rate correct so that the metal is amorphous instead of its natural state of crystalline formation.

The internal structure of SAMs is random, like grains of sand on a beach. Whereas a crystalline metal will break along its orderly cellular structure, an amorphous metal has no pattern and thus will resist breaking. In addition, the smaller the grains, the stronger the metal material. Thus, SAMs are harder, stronger and have more fracture toughness than conventional metals. These materials also tend to have low corrosive properties and high strength.

Another form of materials possible through additive manufacturing are known as Functionally Gradient Materials - FGMs. These  materials combine two metals that don’t combine easily, such as stainless steel and titanium or copper and steel. 

The benefit is you can obtain properties of the individual metals, such as thermal conductivity and mechanical strength, that might be needed in specific applications, such as an aircraft or spaceship part.

To make the FGMs so that there is, for example, 100% copper on one side and 100% titanium on the other, the two sides have to be blended by using other metals to bridge the gap. When done, the new material, which doesn’t appear in nature, exhibits the traits of copper and titanium. 

But because they’re also made through laser melting, they are formed in extreme heat. In this situation, the  cooling rate is critical. It is important to fuse the materials before the microstructure formation or chemical reaction.

This terminology includes terms, definitions of terms, descriptions of terms, nomenclature, and acronyms associated with additive-manufacturing (AM) technologies in an effort to standardize terminology used by AM users, producers, researchers, educators, press/media and others.

The subcommittee responsible for this standard will review definitions on a three-year basis to determine if the definition is still accurate as stated. Revisions will be made when determined to be necessary.