Where once plastics ruled the roost in the 3D printing arsenal, metals are fast gaining ground among additive manufacturers – and soon among consumers.
Once prohibitively expensive – titanium powders currently clock in at around $400 - $800 per pound and above – university researchers and Metalysis have developed a novel approach to producing low-cost titanium powder.
At the Mercury Centre, a branch of the Department of Materials at Sheffield University, a team of materials engineers have developed a low-cost titanium powder made from rutile sand.
Rutile sand is a titanium ore found in beach sands. Until this most recent discovery, rutile sand was most often used as a pigment in the manufacture of refractory ceramics, and it's often found in paints, plastics, paper, foods, and other applications calling for a bright white color.
Until now, manufacturing titanium powder involved a little something called the Kroll process to create billets which were melted into bar form and then rendered into a powder form. It's an expensive and labor-intensive process of four distinct steps. The creation of a porous metallic titanium 'sponge' is followed by leaching or heated vacuum distillation, the 'sponge' is jack hammered out, crushed, and pressed before it is melted in a vacuum arc furnace. It's the repeated melting steps which add significantly to the cost of the final product, and it made the resultant titanium product some six times as expensive as stainless steel.
The Sheffield and Metalysis method use the rutile sand and transform it directly into a powdered titanium using electrolysis. This new low-cost titanium powder can be then be applied to a variety of production processes.
Sir Keith Burnett, Vice-Chancellor Professor at The University of Sheffield, says it's a breakthrough discovery.
"Most people associate 3D printing with plastic parts, but with Metalysis' titanium powder, we have for the first time demonstrated its potential in the manufacturing of metal parts," he said. "This is potentially a significant breakthrough for the many sectors which can benefit from its low-cost production."
And the process will also drive down the cost of producing titanium parts, at least according to Dion Vaughan, the CEO of Metalysis.
"The Metalysis process could reduce the price of titanium by as much as 75%, making titanium almost as cheap as specialty steels," Vaughn said. "We believe that titanium made by the Metalysis process could replace the current use of aluminum and steel in many products."
Titanium is usually considered too expensive for use in automotive manufacturing but a novel process for producing titanium powder from sand has opened the way for 3D printing parts cheaply enough for low-to-medium volume production, according to engineers from Sheffield University.
Professor Iain Todd, a director of the Mercury Centre, thinks the new process paves a path for titanium to be uses in additive manufacturing processes where the cost of materials once made it impractical. The Sheffield team has already created impellers and turbocharger parts using laser additive manufacturing machines which fit nicely into the new material's thermal characteristics.
"I think you're looking at an interesting competitor to standard automotive material," Todd said.