[h=1]3D-Printed Wonder Ceramics Are Flawless And Super-Strong[/h]"You're left with a virtually flawless ceramic."
By William Herkewitz
Dec 31, 2015
There's a reason they're used in everything from jet engines to Formula 1 race car brakes: Ceramics are tough. They can withstand an absurd amount of heat and pressure without warping or breaking, all while brushing off many of the physical and chemical assaults that would rust metals and wear away plastics.
"The problem is that ceramics are just notoriously difficult to process," says Zak Eckel, an engineer at HRL Laboratories in Malibu, California.
Heat-resistant ceramics require crazy-high temperatures to melt, so it's been a struggle to develop methods to 3D-print them. Today, there are just a few 3D printing techniques on the market that use any ceramics (developed by companies like 3DCERAM and Lithoz), but the approaches are severely limited in the types of ceramics they can print, as well as the end quality of their materials. Eckel and his team have just developed an altogether new way to 3D print practically flawless ceramics—including fantastically heat-resistant varieties that've so far been beyond our reach. Their research is announced today in the journal Science.
To understand why Eckel's new printing process creates such interesting ceramics, it helps to understand why today's 3D printing approaches are so limited. To put it simply, they use clever techniques that basically print consecutive layers of ceramic particles that are suspended with a glue-like binding resin. (Imagine sand particles suspended in glue and you've got the idea). Once you're done printing a part this way, you can heat it up in a furnace to fuze the individual ceramic particles together into one big ceramic piece, and dissolve away the binding glue.
So what's the problem? With this approach, "you're limited by the ceramics you can use" says Tobias Schaedler, a materials engineer with Eckel's team. Because you're fusing together individual particles of ceramics in a furnace, you can only use ceramics that melt at lower temperatures. According to Richard Gaignon, the president of 3DCERAM, today's printers can only work with a class of ceramics called "oxide ceramic materials." The second issue is that such ceramics can contain pores and other tiny flaws that are inherent byproducts of the messy process of creating one material by fusing millions of various small grains together.
Eckel's approach is different in a crucial way, and avoids both these issues. Instead of fusing together particles, his team creates ceramics by printing materials that look a lot like plastics—but transform into ceramics when heated in a furnace. "It's actually a pretty simple, straightforward idea," Eckel says.
The team uses a $3,000 printer to print 100 micron thick layers of a plastic-like material out of a resin. That resin contains all the molecules you need to form a tough ceramic. The printing process is done by carefully etching layers of the resin with a UV light, which fuses small molecular clumps (called monomers) into long plastic-like chains (called polymers). Once the plastic-like pre-ceramic part is printed, it's forged in an oven, where it's slowly cooked to 1,000 degrees Celsius in the presence of argon gas. That heating basically tears away all the unnecessary chemical groups attached to the plastic-like material, leaving nothing behind but the strong ceramic framework underneath.
In their first tests, Eckle's group formed silicon carbide ceramics, which have never before been 3D printed. The team also believes the same approach could be used to print a menagerie of various different ceramics, by adjusting the makeup of the ceramic-plastic resin. And because you're forming a ceramic from the ground up, rather than fuzing together individuals grains "you're left with a virtually flawless ceramic," says Schaedler, one with no pores and is remarkably uniform across the entire material.
Source:http://www.popularmechanics.com/science/a18801/3d-printed-wonder-ceramics-wont-shatter/
By William Herkewitz
Dec 31, 2015
There's a reason they're used in everything from jet engines to Formula 1 race car brakes: Ceramics are tough. They can withstand an absurd amount of heat and pressure without warping or breaking, all while brushing off many of the physical and chemical assaults that would rust metals and wear away plastics.
"The problem is that ceramics are just notoriously difficult to process," says Zak Eckel, an engineer at HRL Laboratories in Malibu, California.
Heat-resistant ceramics require crazy-high temperatures to melt, so it's been a struggle to develop methods to 3D-print them. Today, there are just a few 3D printing techniques on the market that use any ceramics (developed by companies like 3DCERAM and Lithoz), but the approaches are severely limited in the types of ceramics they can print, as well as the end quality of their materials. Eckel and his team have just developed an altogether new way to 3D print practically flawless ceramics—including fantastically heat-resistant varieties that've so far been beyond our reach. Their research is announced today in the journal Science.
To understand why Eckel's new printing process creates such interesting ceramics, it helps to understand why today's 3D printing approaches are so limited. To put it simply, they use clever techniques that basically print consecutive layers of ceramic particles that are suspended with a glue-like binding resin. (Imagine sand particles suspended in glue and you've got the idea). Once you're done printing a part this way, you can heat it up in a furnace to fuze the individual ceramic particles together into one big ceramic piece, and dissolve away the binding glue.
So what's the problem? With this approach, "you're limited by the ceramics you can use" says Tobias Schaedler, a materials engineer with Eckel's team. Because you're fusing together individual particles of ceramics in a furnace, you can only use ceramics that melt at lower temperatures. According to Richard Gaignon, the president of 3DCERAM, today's printers can only work with a class of ceramics called "oxide ceramic materials." The second issue is that such ceramics can contain pores and other tiny flaws that are inherent byproducts of the messy process of creating one material by fusing millions of various small grains together.
Eckel's approach is different in a crucial way, and avoids both these issues. Instead of fusing together particles, his team creates ceramics by printing materials that look a lot like plastics—but transform into ceramics when heated in a furnace. "It's actually a pretty simple, straightforward idea," Eckel says.
The team uses a $3,000 printer to print 100 micron thick layers of a plastic-like material out of a resin. That resin contains all the molecules you need to form a tough ceramic. The printing process is done by carefully etching layers of the resin with a UV light, which fuses small molecular clumps (called monomers) into long plastic-like chains (called polymers). Once the plastic-like pre-ceramic part is printed, it's forged in an oven, where it's slowly cooked to 1,000 degrees Celsius in the presence of argon gas. That heating basically tears away all the unnecessary chemical groups attached to the plastic-like material, leaving nothing behind but the strong ceramic framework underneath.
In their first tests, Eckle's group formed silicon carbide ceramics, which have never before been 3D printed. The team also believes the same approach could be used to print a menagerie of various different ceramics, by adjusting the makeup of the ceramic-plastic resin. And because you're forming a ceramic from the ground up, rather than fuzing together individuals grains "you're left with a virtually flawless ceramic," says Schaedler, one with no pores and is remarkably uniform across the entire material.
Source:http://www.popularmechanics.com/science/a18801/3d-printed-wonder-ceramics-wont-shatter/
