Manufacturers Recommended Settings
Personal preferred Settings
220 - 235 °C
Cooling Fan Speed
Max Flow Rate
mm3/s at °C
7 mm3/s at 230 °C
mm @ mm/s
1.17 - 1.24 g/cm3
Diameter & Tolerance
2.85 ± 0.05mm
2.81 – 2.9
Shore Hardness (A)
Glass Transition Temp °C
Blue Tape, Kapton Tape, BuildTak.
1cm3 test piece, 10.20 x 10.15 x 9.90 (mm) (XYZ), weight 1.12g. Density = 1.09g/cm3
PolyMakers’s PolyFlexTM is described as a flexible elastic material, no detail of its chemical makeup is available.
Prints well between 235 -210°C, although stringing is noticeable, Bridging and stringing was best at 230°C.
45-50mm/s is ideal but will print at quicker speeds, I tested up to 105mm/s but I noticed that the bonding between skins deteriorated above 65mm/s.
7mm3/s at 230°C. good bonding between layers, began to fail at 8mm3/s.
0.4mm Nozzle, 230°C, Bed at 40°C with hairspray, speed 50mm/s and fans at 20% I use a set of standard sliced files that I use with all filaments to allow me to compare them against each other.
- Ultimaker Robot: Using 200um layers (0.2mm) produced a well-defined print, good definition to the ear-cups and antenna, as well as the overhangs and bridging, a little stringing to be seen.
- Tree Frog: Again printed at 200um layers, a nice print good definition all round, stringing noticeable around travel points so a little post print clean up required to remove these.
- 3DBenchy: A decent print produced at 200um layers, slight bowing to the bridging of the front window and fine stringing visible but acceptable and would clean up quickly.
- Aztec Chief: A well-defined model built at 100um, good definition all-round with only a little stringing, slightly lost definition with the finishing on the very top feather, but acceptable.
Measurement and % difference
*As the vertical height can be effected by the distance of the bed-levelling to the nozzle the height of the “Top of the Chimney
to the top of the box” should be more accurate for the comparisons.
Conclusion: As with all flexible filaments the flexibility depends on the number of skins and the percentage and structure of the infill, I would class this as not as ‘soft’ as filaments such as ‘Ninjaflex’, and although described as elastic, it is not as elastic as ‘Ninjaflex’. But it prints well with a single wall thickness, if printing flexible hinges this would be a filament to try them with as by increasing the thickness will affect the flexibility and strength, Do store correctly in a sealedbag with a desiccant pack when not in use as PolyFlex tends to slowly absorb atmospheric moisture.
Colours available: Only four colours available, Black, White, Orange & Yellow.
Testing performed on an Ultimaker2, With a BondTec Feeder, an Olsson Block running a 35W heater and using a 0.4mm nozzle