Optical Fibre Spinning Measurement at the Top of the Draw Tower

摘要

Measuring the spinning frequency at the top of the tower is really a challenge that CERSA-MCI has overcome due to the performance of its Laser Interferometric Sensor (LIS) for Glass. Even a slight non-circularity (NC) of the fiber as it spins generates a repetitive diameter fluctuation (One Turn Signature: OTS) that the very fine diameter repeatability (5 nm) and fast frequency measurement (50 kHz) capabilities of the LIS-G instrument can measure in real time at two main conditions: The drawing process is stable enough (LIS priority target). The fiber is not perfectly round (more than 0.05um NC). In this way, we can recognize and track the spinning period evolution. Then, non-circularity, spinning frequency profile and spinning direction change frequency, can be measured (and certified) at the top of the tower. Since early 2008, more than 20 draw towers are benefiting permanently in production from this advanced feature.