A team from Binghamton University has discovered some bottlenecks in 3-D printers that could speed up the entire printing process if they were improved.
This image shows a Z Corp 3-D Printer-Spectrum 2 at Binghamton University's Innovative Technologies Complex. (Binghamton University)
John Hart, a professor from the Department of Mechanical Engineering and Laboratory for Manufacturing and Productivity at the Massachusetts Institute of Technology (MIT) has been working alongside Scott Schiffres, an Assistant Professor of Mechanical Engineering to discover that many conventional desktops and professional AM systems 3-D print at 10 to 20 cubic centimeters per hour when printing at a .2 millimeter thickness. A limitation of the system is a pinch wheel mechanism that is used to feed the building material. The wheel mechanism is limited in the amount of force it can use (about 60 newtons) and the feed rate (about nine millimeters per second) before it can fully melt the building material.
"We found that the rate at which a polymer melts is limiting in many implementations," said Schiffres. "The pressure required to push the polymer through the nozzle is a sharp function of temperature. If the core is not hot enough, the printer will not be able to squeeze the polymer through the nozzle."
"The work has implications for how to scale up additive manufacturing and the trade-off between higher-resolution printing and speed. We hope it will inspire future work to investigate pre-heating of the polymer and printing with multiple extruders," he added.
Paper co-authors include MIT graduate students Jamison Go and Adam Stevens.
The title of the paper is “Rate Limits of Additive Manufacturing by Fused Filament Fabrication and Guidelines for High-Throughput System Design” and is currently available online in Additive Manufacturing.
