Manufacturers Recommended Settings

Personal preferred Settings

Nozzle temperature

220 - 235 °C


Bed Temperature

Not required


Speed (mm/s)

30-90 mm/s

50 mm/s

Cooling Fan Speed


20 %

Max Flow Rate

mm3/s at °C

7 mm3/s at 230 °C


mm @ mm/s

2mm @45mm/s

Other specifications


1.17 - 1.24 g/cm3


Diameter & Tolerance

2.85 ± 0.05mm

2.81 – 2.9

Shore Hardness (A)

~ 95

Glass Transition Temp °C

Bed Adhesive

Blue Tape, Kapton Tape, BuildTak.

Hair spray

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.

TemperaturePrints well between 235 -210°C, although stringing is noticeable, Bridging and stringing was best at 230°C.

Speed45-50mm/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.

Volumetric Flow 7mm3/s at 230°C. good bonding between layers, began to fail at 8mm3/s.

Preferred settings0.4mm 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.

Polymaker Polyflex















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

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3D printing Polymaker Polyflex filament test review