Combine innovations in materials science with additive manufacturing and the outcome is likely to be new products or limitless variations on existing ones. An example is a process for using cellulose in 3D printing developed by a team of researchers at the Massachusetts Institute of Technology (MIT).
John Hart, Associate Professor of Mechanical Engineering, MIT, is one of the researchers. Hart will give a talk at the Crossroads 2017 conference, April 4th, 2017, at MIT, Cambridge, US, about new developments in additive manufacturing. Another Crossroads 2017 speaker, Markus J. Buehler, Professor and Head of Department, Civil and Environmental Engineering, MIT, will talk about materials science innovations.
An abundant polymer, cellulose is inexpensive, biorenewable, and biodegradable. It’s also highly versatile; the material and its derivatives are used in many products including pharmaceuticals, medical devices, foods, building materials and clothing.
By using the natural polymer as a raw material for 3D printers, it is possible to create new, customized products, and extend the range of the additive manufacturing process. Up until now, however, researchers have not been able to adapt the material to 3D printing. It tends to decompose when heated, and cellulose solutions are too viscous to easily extrude.
The MIT team addressed these issues by working with cellulose acetate, a material that is easily made from cellulose and is already in common use. In addition, the researchers have developed an optional treatment applied at the end of the printing process that increases the strength of manufactured parts.
To demonstrate the versatility of the production process, the team added a small amount of antimicrobial dye to the cellulose acetate ink, and 3D printed a pair of surgical tweezers. The custom-made product kills bacteria when bathed in fluorescent light, and could be used in surgical operations in remote regions where it is difficult to maintain a sterile environment.
The new process also offers an important operational benefit where polymers are used as a feedstock. 3D printing production speed is limited by the amount of heat that can be delivered to a polymer without damaging it. But this is less of a problem in the room-temperature cellulose process, which means that production speeds could be faster. Moreover, the team has devised other ways to speed up the process even further.
In bulk, cellulose acetate is comparable in price to that of thermoplastics used in injection molding. Also, the commodity is much less expensive than the typical filament materials used for 3D printing, the researchers say. This, combined with the ability to functionalize cellulose in a variety of ways, could make it commercially attractive.
This post is based on a recent article published in MIT News.