The infancy of any emerging technology is a very exciting time and 3D printing, a relatively new technology, has emerged as an extremely promising technology with various applications. While, the benefits of traditional 3D printing are widely acclaimed, every technology in their infancy can be improved upon. One of the main disadvantages of traditional 3D printing is the medium itself. The various plastics used as printing material require support throughout the entire printing process. These supports are immediately stripped off and usually discarded when the process is completed. Lately, there has been an increase in demand for flexible electronics, such as, sensors, antennas,biomedical devices and wearable electronics, but this printing process leaves a rigid and nearly inflexible product. A new technology developed by Harvard’s Wyss Institute and the School of Engineering and Applied Sciences (SEAS) aims to fix this problem by 3D printing in mid-air, through the use of nanoparticles and lasers.
Instead of using plastic, this experimental 3D printing technology utilizes an ink comprised of silver nanoparticles. The “ink” is inserted into a nozzle that can extrude and move in the X, Y, and Z axes. Once ink is extruded from the nozzle, it is exposed to a laser’s thermal emissions and allows for solidification of the nanoparticles midair. With this technology, the team was able to design intricate objects, such as tiny silver butterflies and spirals, with nanowires that are thinner than human hair.
The team devised a heat transfer model that takes temperature distribution into account while printing. This method, according to the study’s first author, Mark Skylar-Scott, “allows [us] to modulate the printing speed and distance between the nozzle and laser to elegantly control the laser annealing process ‘on the fly’”. The advantages to this type of 3D printing include the ability to print silver wires directly onto low-cost plastic substrates, meaning that it can be used to print flexible, wearable electronics and biomedical devices. This method of metallic 3D printing also inspires many new products, as the design and physical constraints of traditional 3D printing do not apply to this technology.
Although this technology fixes issues related to traditional 3D printing, it also has its downsides. The printer has a small build volume and is complicated to maintain, due to the nozzle’s sensitivity to the laser’s heat. However, this innovative experimental technology has much promise and limitless potential applications. Its small build volume and ability to print sharp changes in direction opens up applications in creating objects that require high precision and accuracy in areas including, but not limited to, medical device design and electronics. With time and development, this technology may have a larger influence in the industry.
By Alyna Pradhan