PC (Polycarbonate): 

Polycarbonate is a high strength material with improved heat resistance over other engineering thermoplastics. PC is widely used by traditional manufacturing methods for industrial, consumer, electronics, and telecommunication applications. Due to it's increased strength and heat resistance it is used in high stress, load bearing applications.

Within the 3D printing community it is the strongest materials and it is used to directly manufacture production parts that can withstand a temperature of up to 145 °C in air.

3D printing with polycarbonate:

Like many engineering thermoplastics, polycarbonate will contract when cooled, therefore it will develop interlayer stress at the interface between a new hot layer 3D printed on top of a cold layer or bed surface. That can result in layer adhesion problems with the printing bed or in between 3D printed layers, and/or curling (upwards bending of the part corners and sides). This curling is more pronounced as the 3D printed object size is increased. The stress release behavior can be avoided by maintaining the entire 3D printed object at a temperature close to the glass transition temperature of the material and then cool it in its entirety after the 3D printing process is completed. Glass transition temperature is where the thermoplastic softens and becomes plastic (malleable, soft). Curling issues are more significant than with other materials due to higher 3D printing temperature for PC. 

3FXtrud Uno printers use a heated bed which provides consistent and uniform heating across the whole bed surface. 3FXtrud Duo series of 3D printers have a heated bed and a full enclosure around the 3D printed volume which provides a consistent, stable, uniform warm air environment around the printed objects, thus improving the whole 3D printing process by minimizing further the interlayer stress problem. The enclosed printed volume is needed for 3D printing Polycarbonate parts.

PC used for 3D printing will extrude above 285 °C. For good layer adhesion and reasonable fast printing speeds, it will print at a higher temperature of around 300 - 310 °C. A reliable 3D printing head (or extruder) needs to withstand these temperatures for an indefinitely long time. 3FXtrud printers use a whole metal hot end design which works reliably and provides consistent 3D printing polycarbonate parts. 

3D printing requirements: 

A heated bed that can operate at least 130 °C is required, along with an enclosure around the printed volume to prevent warping and a hot end that can sustain 300 °C continuously. PC is available in 1.75 mm and 3 mm.

Pyra 2 uses 3 mm filament, while the newer 3FXtrud 20 Uno, 3FXtrud 25 Uno, 3FXtrud 25 Duo, and 3FXtrud 30 Duo use 1.75 mm.