High-Area Rapid Printing (HARP) enables a record-breaking throughput that can manufacture products on demand. The prototype HARP system is 13 feet tall with a 2.5-square-foot print bed and can print about half a yard in an hour. It can print single, large parts or many different small parts at once.

HARP uses a new, patent-pending version of stereolithography, a type of 3D printing that converts liquid plastic into solid objects. HARP prints vertically and uses projected ultraviolet light to cure the liquid resins into hardened plastic. This process can print pieces that are hard, elastic, or even ceramic. These continually printed parts are mechanically robust as opposed to the laminated structures common to other 3D printing technologies. They can be used as parts for cars, airplanes, dentistry, orthotics, fashion, and much more.

HARP can print soft, flexible parts in addition to hard, durable objects. (Credit: Northwestern University)

A major limiting factor for current 3D printers is heat. Every resin-based 3D printer generates heat when running at fast speeds — sometimes exceeding 180 °C. Not only does this lead to dangerously hot surface temperatures, it also can cause printed parts to crack and deform. The faster it is, the more heat the printer generates. And if it’s big and fast, the heat is incredibly intense.

The new technology bypasses this problem with a nonstick liquid that behaves like liquid Teflon. HARP projects light through a window to solidify resin on top of a vertically moving plate. The liquid Teflon flows over the window to remove heat and then circulates it through a cooling unit. The interface is also nonstick, which keeps the resin from adhering to the printer itself, increasing the printer’s speed by a hundredfold because the parts do not have to be repeatedly cleaved from the bottom of the print vat.

Current manufacturing methods can be cumbersome processes. They often require filling pre-designed molds, which are expensive, static, and take up valuable storage space. Using molds, manufacturers print parts in advance — often guessing how many they might need — and store them in giant ware-houses. Although 3D printing is transitioning from prototyping to manufacturing, current 3D printers’ size and speed have limited them to small-batch production. HARP can handle large batches and large parts in addition to small parts.

Printers on the scale of HARP often produce parts that must be sanded or machined down to their final geometry. This adds a large labor cost to the production process. HARP is in a class of 3D printers that uses high-resolution light-patterning to achieve ready-to-use parts without extensive post-processing.

Watch a demo of HARP on Tech Briefs TV here. For more information, contact Amanda Morris at This email address is being protected from spambots. You need JavaScript enabled to view it.; 847-467-6790.

Tech Briefs Magazine

This article first appeared in the April, 2020 issue of Tech Briefs Magazine.

Read more articles from this issue here.

Read more articles from the archives here.