Engineers at Northwestern University in Illinois developed a method of 3D printing that uses light to improve the speed and precision of the process.

Most 3D printing is done by slicing a digital model into layers and programming a machine to build a product by depositing material in the right spots, layer by layer. The Northwestern process allows real-time manipulation of the digital model to quickly pivot the printing direction and manipulate the original design at each layer.

• Northwestern’s engineers used a robotic arm and a light-activated liquid polymer, as opposed to the solid materials usually used in additive manufacturing. Shining a light onto the polymer makes it harden into a solid object. The photopolymer’s properties allow it to be more easily manipulated during manufacturing.
• “The 3D printing process is no longer a way to merely make a replica of the designed model,” Cheng Sun, associate professor of mechanical engineering, said in a news release. “Now we have a dynamic process that uses light to assemble all the layers but with a high degree of freedom to move each layer along the way.” 
• This process works well with soft or flexible objects. Traditional 3D printing works for rigid objects, but flexible objects tend to be of lesser quality or fall apart. The Northwestern researchers made a vascular stent and a pneumatic gripper from their photopolymer.

The process is much more efficient, precise, and faster than traditional 3D printing. It can print a product in seconds or minutes, compared with the hours it often takes with existing methods. The efficiency gains and precision could result in less energy consumption and less manufacturing waste.

“This is a very fast process, and there is no interruption between layers,” Sun said. “We hope the manufacturing industry will find benefit in it. The general printing method is compatible with a wide range of materials.”