FTT Fiber Tenacity & Elongation Tester

Tenacity is the breaking force of a fibre expressed per unit linear density (typically cN/dtex or cN/tex). It allows meaningful comparisons of fibre strength independent of the fibre's fineness. The FTT measures breaking force directly in cN, N, Kgf, or lb as the crosshead stretches the clamped single fibre at a constant rate until it breaks. The instrument records the peak force (breaking force) and the crosshead displacement at break (elongation). Tenacity is then calculated by dividing breaking force by the fibre's linear density, which can be entered by the operator or obtained from a separate linear density test.

The FTT is available in two load-cell configurations: 500cN and 1000cN. The 500cN model is suited for delicate fibres such as fine silk, ultra-fine polypropylene, and low-denier synthetics, where high measurement resolution is critical. The 1000cN model handles heavier fibres such as coarse wool, glass fibre, and metallic thread where higher breaking forces are expected. Both models share the same 0.01 cN resolution and 0.02% (F.S) accuracy specification. Please specify the required capacity when ordering.

The FTT can display breaking force in cN (centinewtons), N (newtons), Kgf (kilogram-force), or lb (pound-force), selectable from the touch screen. This flexibility allows the instrument to be used directly with any international standard without requiring manual unit conversion: ISO and BS standards typically express results in cN or mN/tex, while older or non-metric standards may use gf or lb. Maximum, minimum, and average breaking force values are automatically computed and displayed after each batch of tests.

The FTT complies with ISO 5079 (Textile fibres — determination of breaking force and elongation at break of individual fibres), ISO 11566 (Carbon fibre — determination of the tensile properties of single filament specimens), ASTM D 3822 (Standard test method for tensile properties of single textile fibres), BS 4079, IS 17266, and IS 235. These standards collectively cover natural fibres, synthetic fibres, carbon fibres, and specialty filaments, ensuring the instrument is accepted for quality control and certification testing across Indian and international supply chains.

The FTT is supplied with two sets of fibre-holding grips. While one fibre specimen is being tested in the instrument, the operator can prepare and mount the next specimen in the spare set of grips. Once the test is complete and the result is recorded, the grips are exchanged rapidly — minimising the dead time between consecutive tests. This design is particularly valuable when testing large batches of single fibres, as required by ISO 5079, which specifies a minimum of 20 replicate measurements per sample for reliable statistical results.

Test speed is adjustable from 1mm/min to 200mm/min. The correct speed for each test is specified by the applicable standard and fibre type: ISO 5079 specifies a rate of extension such that the time to break is 20 ± 3 seconds, while ASTM D 3822 specifies a crosshead speed of 12mm/min for the standard 20mm gauge length. Incorrect speed introduces a systematic error into breaking force and elongation results. The FTT's wide speed range ensures full compliance with all major methods, and the servo drive maintains the set speed precisely without hunting or overshoot.

The FTT requires a standard 220V, 50Hz single-phase power supply. It weighs 55 kg and has a compact bench-top footprint of 400 × 450 × 600mm (L×W×H), making it suitable for placement on a standard laboratory bench without structural modification. No special environmental conditioning is required beyond the standard laboratory atmosphere specified by the test method (typically 20°C ± 2°C and 65% ± 4% RH per ISO 139). The instrument is supplied by Apple Electroniks, Vadodara, with installation guidance and after-sales support.