All You Need to Know About ULTEM/PEI for 3D Printing

In recent years, the use of high-performance thermoplastics has become increasingly important in the 3D printing industry, as the technology moves away from rapid prototyping to the production of finished parts. As a result, the requirements for 3D printing materials have increased and high performance thermoplastics are becoming more and more common. Their properties make them an economical alternative to certain metals and are valued by many sectors such as aerospace and medical. Within this family are Polyaryletherketone (PAEK) which can withstand high temperatures and which you may be familiar with from PEEK and PEKK. There is a much cheaper alternative, Polyetherimide (PEI), an amorphous material better known by its trade name ULTEM®. Available as a filament for FDM 3D printers, it is compatible with certain machines, including those of Stratasys. Let’s go back over the main characteristics of ULTEM.

PEI was developed in the 1980s by Joseph G. Wirth and was marketed by General Electric’s Plastics Division under the name ULTEM. In 2007, the company sold its plastics business to Saudi Basic Industries Corporation (SABIC), which thus recovered the associated patent. Although ULTEM® was embraced by many industrialists thanks to its mechanical properties, it only became suitable for mass production with the development of high-performance FDM/FFF printers; the extruder of the machine must be heated up to 350°C in order to melt the thermoplastic.

Photo credits : GEWO3D

Production and Characteristics of ULTEM/PEI

ULTEM® is a group of thermoplastic materials derived from Polyetherimide (PEI). Notably, ULTEM exhibits exceptional flame retardancy, characterized by high resistance to flames, minimal smoke generation, and low toxicity. These properties are validated by excellent performance in Flame, Smoke, Toxicity (FST) tests. Additionally, ULTEM demonstrates remarkable resistance to elevated temperatures, boasting a relative thermal index (RTI) of up to 180°C. The material is distinguished by its superior strength, rigidity, dimensional stability, creep resistance, and chemical resistance. Its various formulations offer a high weight-to-strength ratio, allowing them to potentially replace certain metals while maintaining excellent machinability.