NCTM Non-contact Tension Measurement


Optical fibers are obtained from a glass droplet that is drawn along a vertical drawing tower. The tension is an essential parameter to be measured and adjusted during the different phases of manufacturing and drawing of the fiber. The NCTM is a system for measuring the tension (force) applied to this few hundred-micron fiber to obtain a constant diameter and also to avoid its breakage.

Wire tension measurement device

CERSA is the first measurement system manufacturer to have developed an instrument based on the optical principle of birefringence. This principle is much more accurate and reliable for measuring the tension applied during the fiber drawing process than the commonly used vibrating string method. The NCTM is able to cover a measurement range of 0 to 400 grams with an uncertainty of +/-1 gram.

Non-contact drawing force measurement: an essential parameter

A system that has become indispensable for the perfect regulation of the fiber drawing process during the start-up, stabilization and stopping phases. A simple, accurate and robust instrument that has won over many optical fiber manufacturers worldwide for the analysis of fiber tower parameters.

Customized versions (higher tension range and larger diameters) are available on request for manufacturers of special fibers.

NCTM features:

  • Measurement of the tension of the bare optical fiber (125µm).
  • Precise measurement of the fiber position (assists with the positioning and alignment of the drawing tower)

Digital and analog inputs and outputs, RS232 output, fieldbus options, are used to connect the NCTM to the tower PLC for control loop needs and measurement analysis.