Thursday, 22 November 2012

The Big Friendly Giant (BFG) of 3D Printing - Glassy (Amorphous) Metals

If anyone questions whether the term "3D Printing" is slightly ridiculous, referring as it does to so many utterly different processes, add in the orthogonal dimension of materials science and you'll see why.

A small research company in Sweden has announced a unique breakthrough in bulk "metallic glass" manufacturing.
For those of us outside the field of materials sciences, BFG stands for The Big Friendly Giant, a character in a children's book of the same name by Roald Dahl. To a materials scientist it is Bulk Metallic Glasses or glassy alloys.

To a scientist, the technical term 'glass' means far more than window-glass. It refers to amorphous (non-crystalline) materials and their transition states, e.g. from hard and brittle to soft and rubbery. It turns out that a wide range of materials can exhibit an amorphous state, including metal alloys and polymers.

Transparency is associated with the amorphous state. But whereas ordinary glass is an insulator, a glassy metal can be an electrical conductor.

Exmet's breakthough is that they have demonstrated how the additive manufacturing process called Electron Beam Melting can be used to make products from Glassy Metals. The material is extremely strong (2 to 15 times that of a normal crystalline metal), extremely plastic, non-corrosive and potentially highly resistant against metal fatigue. Thus, just as using polymer rather than ordinary glass for eye lenses results in a much lighter pair of reading glasses, glassy metals could bring similar benefits to a range of industrial product areas, including biomedical implant manufacturing. Imagine for example, a titanium amorphous state.

Previously, production of glassy metals was limited by  inadequate manufacturing methods set by traditional approaches such as casting, melt spinning and thermoplastic forming.

More info here

Take away: This story illustrates why the impact of additive manufacturing on global manufacturing supply chain cannot be judged by adopting a broad term such as "3D Printing".

When working with clients, AM consultants look to the details and intersection of materials science and additive processes. They contextualize the possibilities within the design process of existing products or for the potential of new products needed in the world. It's a constantly changing maze.

Each 3D Printer maker is always trying to extend the range of materials available for their process. This applies whether you are MakerBot (Fused Deposition Modelling) at the 'enthusiast engineer' end of the market with PLA, ABS and PVA filament or Objet (advanced 'Inkjet' 3D Printing) for the production of professional prototype or 'end use' parts with a range of over one hundred photo-curable polymers.

At the same time, materials suppliers are constantly improving and adapting existing materials or are developing new materials for use within existing AM processes. This applies whether you are faberdashery at the 'maker' end of the market creating unique filament for your RepRap spool, or Exmet at the extremes of materials R&D conjuring up 'glassy metals' for use on Arcam Electron Beam Melting (EBM) machines.

No comments:

Post a comment