Every spec number on a filament datasheet comes from a test. Knowing the test tells you how much to trust the number.

The standard tests

  • Tensile strength (ISO 527 / ASTM D638): pulls a printed dogbone until it breaks — MPa. Print orientation matters: X/Y parts are stronger than Z.
  • Flexural modulus (ISO 178): bends a bar to measure stiffness — GPa. PA-CF's 6.2 GPa shows here.
  • Impact (Izod/Charpy): strikes a notched sample — J/m. Measures toughness, not just strength.
  • HDT (ISO 75): heats a loaded bar until it deflects — °C. Predicts hot-car performance.
  • Moisture content: a moisture analyzer dries a sample and weighs the loss — %.
  • Color ΔE: a spectrophotometer compares the sample to the master color.

How to read a spec sheet

Check the test standard (ISO/ASTM), the test conditions (drying, speed), and whether numbers are from printed samples or pellets. Printed-sample numbers are what you'll actually experience.

VOXFIL measures every material in-house with standardized methods and publishes the data on each material page — plus batch reports with bulk orders.