There is a reason 3D printing isn’t often used in manufacturing: it’s slow. Despite the use of the term “rapid prototyping,” it can still take several hours to 3D-print even a small part. That’s worthwhile if you just need to make a one-off prototype, but it’s generally far too inefficient to be acceptable for manufacturing. If, however, printing speeds could be improved, 3D printing could replace traditional manufacturing processes and remove the logistical headaches associated with them. That’s what Northwestern University researchers are hoping to achieve with their new HARP 3D printer.
HARP stands for “high-area rapid printing,” which is exactly what it achieves. HARP is an 13-foot-tall SLA (stereolithography) 3D printer, which works by hardening liquid resin with ultraviolet light. SLA 3D printers are already fairly popular, as they usually produce higher quality parts than FFF (Fused-Filament Fabrication) 3D printers. While many SLA 3D printers can cure all of the geometry in a single layer at the same time, that still takes a little bit of time. When you have thousands of layers to print, tall parts can take a very long time to complete.
This new 3D printer is able to significantly decrease the amount of time it takes to cure a layer, and does so by keeping cool. While other 3D printers could print more quickly, they generate too much heat when they do. That weakens the part and creates hazardous conditions. HARP uses a “liquid Teflon” coolant that washes over the projection window to cool things down. That cooling is enough to let HARP run very quickly—up to 18 inches per hour over the entire 2.5 square-foot build area. This technology has the potential to print quickly enough to be practical for manufacturing. Amazon could, for instance, 3D-print your product as soon as you order it, and then have a driver deliver it, eliminating the need for stocked warehouses and traditional shipping costs.