Researchers at the University of Massachusetts Lowell say they have pioneered a new technology that combines elements of 3D printing and injection molding.
Called injection printing, the technique uses material extrusion to print shells, which form cavities that are filled like injection molding.
The marriage of the two processes increases the production rate of 3D printing while improving the strength and properties of the resulting products, according to David Kazmer, a plastics engineering professor who led the research project and has filed a patent on the technology.
More durable prosthetics and medical devices as well as stronger parts for airplanes and automobiles are some of the products that could be created through injection printing, Kazmer said in a news release.
The innovation typically produces objects about three times faster than conventional 3D printing, which means jobs that once took about nine hours now only take three, Kazmer added.
"The invention greatly improves the quality of the parts produced, making them fully dense with few cracks or voids, so they are much stronger. For technical applications, this is game-changing," Kazmer said. "The new process is also cost-effective because it can be used in existing 3D printers, with only new software to program the machine needed."
The global market for 3D plastics printers is estimated at $4 billion and growing, Kazmer said, but challenges remain in ensuring the printers create objects that are produced quickly, retain their strength and accurately reflect the shape desired.
An abstract posted on ScienceDirect says injection printing addresses these issues "by combining material extrusion of the outer surfaces of the part at fine resolution with injection molding of larger interior cavities at high flow rates. Injection printing thus aims to utilize the full melting capacity of material extrusion printers to mitigate the curse of dimensionality that plagues additive manufacturing."
Kazmer, who teaches courses in product design, prototyping and process control, said his patent-pending process took about 18 months to develop. Austin Colon, a UMass Lowell doctoral candidate in plastics engineering, helped validate the technology.
The validation process involved printing impact specimens and tensile bars of ABS.
The results show injection printing promises to be a broadly applicable and readily accessible process for increasing part strength and production rate while enabling improved feature resolution without greatly extended print times, the abstract says.