Essentium PCTG

Essentium is a company with headquarters in the USA and branches in Asia and Europe. In their product portfolio they have industrial 3D printers and technical filament. They are revolutionizing the 3D printing world with their innovative solutions and ushering many companies into Industry 4.0. Essentium has helped many manufacturers to prototype and manufacture in-house, upscale their production with excellent quality but in a quick and affordable way. Essentium has numerous high-end technical filaments in their product range, mostly polymers and blends optimized for exceptional strength, flexibility and high mechanical performance in the most challenging industrial conditions. The Essentium filaments have many applications across numerous disciplines, such as aerospace and defense, automotive, biomedical, contract manufacturing, consumer goods, and electronic manufacturing.

Innovative versatile filament

The PCTG is one of Essentium’s hightech materials and it belongs to the family of general purpose materials (variety of uses). It is composed of >99 % copolyester and <1 % additives.

PCTG is an entry-level high-performance engineering polymer. To become PCTG, PET is subjected to the process of glycosylation by adding the CHDM glycol. When more than 50 % of the ethylene glycol units of PET are replaced with CHDM, PCTG is created. The extra dose of CHDM units gives PCTG its increased mechanical properties and improved chemical resistance. PCTG is a semi-crystalline copolyester but it crystallizes very slowly. This means that most parts 3D printed with a PCTG filament will be in the amorphous state at first, which will result in excellent optical clarity and toughness. The downside is that amorphous polymers usually have lower heat deflection temperature, lower tensile strength, lower elastic modulus and decreased chemical resistance.

Those properties can be changed by annealing the amorphous PCTG to cold-crystallize it, by putting the prints in an oven at above the glass transition temperature for a few hours. A piece subjected to that crystallization process will have improved thermomechanical properties due to increased crystallinity. The ability to be both amorphous and semi-crystalline depending on the thermal conditions is unique to PCTG. It makes it a highly versatile material since it allows the user to choose the processing method to obtain an amorphous or semi-crystalline state of PCTG, depending on the application the final piece is going to have. PCTG is mostly used in the biomedical industry to print medical devices such as prosthetics, as well as in manufacturing to make jigs and fixtures.

Image 1: A prosthetic printed with Essentium PCTG. Source: Essentium.

Improved properties

The Essentium PCTG is characterized by its excellent surface finish and clear transparency (in its natural form). It is easy to print (can be printed in open air and over a big temperature range), machine and postprocess, and it is not affected by humidity.

This filament has a similar strength and stiffness as PETG but greater impact strength and chemical resistance. The excellent impact strength of PCTG is demonstrated by the result of the Izod impact test, in which the Essentium PCTG achieved the highest mark - the no-break condition. Moreover, the impact resistance of the Essentium PCTG is bigger than that of polycarbonate, the material that bulletproof glass is made of. The Essentium PCTG also boasts great thermal and chemical resistance (by annealing).

Image 2: The Essentium PCTG subjected to the Izod impact test. Source: Essentium.

All those qualities make the Essentium PCTG an easy-to-use, qualified, versatile and low-cost option for many applications. The manufacturer recommends it for the biomedical industry and rapid prototyping. Some example uses for the Essentium PCTG would be handheld tools, part trays, gauges, location fixtures, general assembly fixtures and check sockets for prosthetics.